Question-Answer Assignment

Relationship Between a Stimulus and the Resulting Movement

In the use of assistive technologies, there are many situations in which a device generates an output that requires a response by the user. This output can be thought of as a stimulus and the user’s resulting movement as a response. For example, most computers now use a GUI that displays a set of small

pictures (icons) depicting the action to be taken. There are icons for loading a file, running a program, erasing a file, and many others. An icon is selected by moving an on-screen pointer by using a mouse—an aimed movement to a target. The relationship between the stimulus (in this example, an icon) and the response (movement of the cursor with the mouse) is important. Fitts and Deininger (1954) used the term stimulus-response (S-R) compatibility to describe improvements in motor performance that resulted from a close relationship between the stimulus and the response. Fitts and Deininger used the task of a radial movement from the center of a circle to one of eight targets located around the circle to study S-R compatibility. The subject was asked to move to one of the eight locations as quickly as possible after a stimulus that represented one of the eight locations. Four stimulus sets were used in this experiment: (1) eight lights arranged in a pattern around a circle, corresponding to one of the eight target locations (spatial two-dimensional set); (2) numbers corresponding to locations around a clock face (1:30, 9:00, etc.) (symbolic two-dimensional set); (3) a horizontal string of eight lights (one-dimensional stim- ulus set); and (4) eight three-letter first names, each assigned to one of the eight locations (symbolic nonspatial set). Fitts and Deininger recorded reaction time and number of errors for each stimulus set to determine whether any of them led to increased performance (faster times and fewer errors). The fastest response times and fewest errors were obtained with the spatial two-dimensional stimulus set (clock face). This set was familiar to the subjects. The symbolic two- dimensional set (common three-letter names) was second best, followed by the one-dimensional and symbolic nonspatial sets. Therefore, the sets with the least similarity to the task were the slowest and least accurate.

The implication for the design and use of assistive tech- nologies is that motor performance can be improved if the correspondence between the stimulus and required response is high. For example, in a GUI a stored file can have a picture of a file folder and the data file system can be portrayed as a filing cabinet. Because of the limited motor experiences of many disabled persons, S-R compat- ibility may be considerably different from that of subjects without motor impairments (e.g., manipulation of objects may have been limited and file folders may be meaningless). As motor experience increases, the number of available motor responses may increase, and this creates more options for stimuli that match desired responses.

EFFECTOR FUNCTION AS RELATED TO ASSISTIVE TECHNOLOGY USE

The human operator controls the assistive technology through the various effectors, and the effectors enable manip- ulation of the environment in a variety of ways. The presence

P A R T I Introduction and Framework 81

CASE STUDY

DOUG

At the time of assessment, Doug was a very proficient user of the HandiVoice 120 (Phonic Ear, Inc., Mill Valley, California). His overall communication rate, determined during an interview, was 26 words per minute. He used whole words and phrases (selected with a single three- digit code) approximately 65% of the time and individual phonemes 35% of the time. Because of his cerebral palsy, he had some difficulty in hitting the keys, and our initial naive assumption was that by providing the equivalent of the three-digit codes on individual keys and therefore reducing the number of keystrokes, his overall rate would increase dramatically. This solution was addressed by placing the individual phoneme and word or phrase labels on the keys of a computer, with the corresponding words or phrases of the phonemes being spoken on key activation. To our surprise, he was unable to use these labels; they were no longer meaningful to him. We then substituted the three-digit codes for the word or phoneme labels. Once again, Doug was unable to access the vocabulary with which he had demonstrated such facility when using the HandiVoice directly. At Doug’s suggestion, we placed the HandiVoice next to the com- puter keyboard, and he looked at the keyboard, visual- ized the movement required, and then entered the correct word or phoneme codes to generate his message. He had, in fact, developed a set of motor patterns or engrams that he used with the HandiVoice, and he no longer made use of either the phoneme or word labels or their corresponding codes; his motor learning associ- ated with the use of the HandiVoice had progressed to the stage of maximizing motor performance in the absence of cognitive attention to target locations. This skill had developed over long periods of practice with a carefully designed training program using the HandiVoice. This outcome, in retrospect, was predictable on the basis of the concepts of aimed movements and reduction in hand path variability with practice described by Georgopoulos, Kalaska, and Massey (1981) and Flash and Hogan (1985). It is also consistent with the common experience of not being able to recall a phone number but being able to dial it once the motor pattern is begun.

of disability dramatically alters the use of effectors. Several factors are important to keep in mind when effector use is considered for the purpose of controlling assistive technolo- gies. First, there are a variety of ways of accomplishing the same task. For example, people type using fingers, toes, head wands, mouthsticks, and many other methods. This diver- sity in accomplishing tasks opens up many options that would not be considered if we were restricted to the com- mon ways of doing things. Second, effector function cannot be interpreted from the point of view of a nondisabled person. We must attempt to obtain the perspective of the person with a disability; this underscores the importance of includ- ing this person in the process of service delivery.

Description of Effectors

Effectors provide the motor outputs that underlie both stabilization and control. The large muscles of the trunk and pelvis provide strength for stabilization of the body. This stabilization is required for manipulation, or control. Control effectors include hand or finger, arm, head, eye (oculomotor control), leg, foot, and respiration and phonation. These effectors are described in this section, and the processes by which an individual person’s capabil- ities in the use of these effectors are assessed are discussed in Chapter 4.

Figure 3-10 shows the body sites that can be used to con- trol a device. These are referred to as control sites. Each con- trol site is capable of performing a variety of movements. The mouth can be used in a number of ways, depending on the individual’s capabilities. The flow of air can be used as a control signal. This regulation of air flow requires chest muscles and diaphragm control; to use air flow as a control signal, the individual must be able to control his or her respiration. Respiratory flow can be detected by sip (inhaling) or puff (exhaling) switches. Air flow that also includes sound production by the vocal folds is referred to as phonation. Phonation may produce sounds (including whistling) or speech. Sounds can also be detected by various control inter- faces. If the individual is able to use speech, we can use speech recognition as a control interface. Tongue movements can also be used for control.

For many persons with severe disabilities, eye gaze tech- niques are the first that are used as control signals in aug- mentative communication systems, and this method of communicative output can be developed to a high degree of competence (Goossens and Crain, 1987; Nolan, 1987). Often the first communication after a major injury (such as a traumatic brain injury) is yes/no questions answered by eye blinks or eye movement. The eyes can also be used in the control of assistive devices by use of control interfaces that detect eye movements. For these reasons, oculomotor func- tion is included with other effectors. Erhardt (1987) uses the following terms, which emphasize the role of the oculomotor

system as an effector: visual approach (localization), visual grasp (fixation), visual manipulation (ocular pursuit), and visual release (gaze shift). When the role of the oculomotor system is considered in these terms, its role as a control site is clear. For example, identification, selection, and indication of vocabulary elements in augmentative communication sys- tems involve all these oculomotor tasks. For eye movements to be used to access an assistive device, the eye movement must be detected and it must be used as a signal for commu- nication or control. Often eye movements are observed by another person, and the control or communication is carried out by that person (see Goossens and Crain, 1987, for example). However, there are also electronic systems that can measure eye position and use it as a control signal. Control interfaces for all these effectors are described in Chapter 7.

The head can be used as a control site in a number of ways. Movements of the head include tilting side to side, vertical movement, horizontal rotation, and linear forward and backward movement. Very few functional movements are purely horizontal or vertical or purely rotational with no tilt; most movements of the head are combinations of these components. Upper extremity sites include the movements of the shoulder, elbow, forearm, and hand and finger. Shoulder movements include elevation, flexion, extension, abduction

82 C H A P T E R 3 Disabled Human User of Assistive Technologies

H Knee/Leg

I Foot

D Mouth

C Eye

B Forehead

A Head

E Chin

F Elbow/Arm

G Hand

Figure 3-10 Anatomical sites commonly used for control of assistive technologies. (From Webster JW, Cook AM, Tompkins WJ, Vanderheiden GC: Electronic devices for rehabilitation, New York, 1985, John Wiley and Sons, p. 207.)

(away from the body), and adduction (toward the body). The movements of the elbow are flexion and extension. The movements of the forearm consist of pronation (turning the palm down) and supination (turning the palm up). The wrist can flex or extend or move from side to side (radial deviation or ulnar deviation). The fingers can individually flex and extend or, together, perform a grasp and release movement. The thumb can flex and extend, abduct and adduct, and oppose each of the fingers. Control movements used in the lower extremities include raising and lowering of the leg at the hip (e.g., hip flexion and extension), knee flexion and extension or knee abduction and adduction, foot plantar flexion (toes point down) or dorsiflexion (toes point up), and foot inversion or eversion (side to side).

When the interaction between a person with a disability and an assistive device involves relatively fine control, the hand and fingers are the preferred control site because they are typically used for manipulative tasks. Even if hand con- trol is limited, it may still be possible to enhance the exist- ing function by using assistive technologies, which makes it possible to use hand movements for control. If the hand is not controllable, then the use of the head as an interface site is preferred. With pointers of various types as control enhancers (e.g., a head pointer), it is possible to obtain rela- tively precise control with the head. Oculomotor control is most often used for indicating choices in augmentative communication when no other control site is available for pointing. Eye-controlled switches can be used for gross con- trol by using the eyes. Voice allows for relatively fine control with many possible control signals. Simple air flow with no speech is generally more gross and restricted to a few signals. For some individuals, fine control of the foot is possible. For fine manipulative tasks, the foot is less desirable than the hand or head because visual monitoring can be difficult and the foot is generally not as finely controlled as the hand. The use of the arm or leg is less desirable for precise tasks because these represent naturally gross movements controlled by large muscle groups. For this reason, they are the least desir- able for manipulative functions.

Although generally an individual’s “best” available con- trol site is used, in some cases more than one control site must be identified. This situation most often occurs when one person uses several types of assistive technologies. For example, head control may be used for augmentative com- munication and foot control for a powered wheelchair. In other cases, such as with some neuromuscular disabil- ities (e.g., amyotrophic lateral sclerosis), multiple sites need to be identified because of progressive paralysis. The course of this progression can vary from months to years. The variation in ability to use effectors over the course of the disease makes it necessary to find flexible control inter- faces that can be used with multiple control sites or to find separate control interfaces for several sites initially (see Chapters 4 and 7).

Factors Underlying the Use of Effectors

Two primary factors underlying the use of effectors are automatic movements and muscle tone. The former consists of primitive reflexes, righting reactions, and equilibrium reactions (Hopkins and Smith, 1993).

Primitive reflexes are characterized by immediate and automatic movement performed at a subconscious level (Hopkins and Smith, 1993). They are usually initiated by sensory stimulation. Present at birth or shortly thereafter, these reflexes are inhibited or (more often) integrated into volitional movements to control posture and perform basic movement patterns as the infant develops. Neurological damage before or at birth may affect the degree to which the infant is able to integrate or inhibit these reflex patterns, resulting in delayed motor development and impaired motor control (Fiorentino, 1978). Neurological damage later in life can also reduce the individual’s ability to inhibit some of these primitive reflexes, resulting in impaired postural control and movement patterns.

Hopkins and Smith (1993) tabulate 17 primitive reflexes, including their initiation, stimulus, response, and adaptation in later life. The primitive reflexes that most commonly influence effector use are the asymmetrical tonic neck reflex and the tonic labyrinthine reflex (Trefler, 1984). The asym- metrical tonic neck reflex occurs when the head is turned to one side, the arm on that side is extended, and the opposite arm is flexed. This reflex makes it difficult for the person to hold his trunk and head in midline, prevents use of both hands together, and contributes to scoliosis (Trefler, 1984). The tonic labyrinthine reflex is displayed by increased exten- sor tone in the supine position and increased flexor tone in the prone position. When sitting, the result is increased extensor tone in the lower limbs, trunk, and neck, causing the person to slide forward in the chair (Davies, 1985).

Righting reactions and equilibrium reactions respond to more global stimuli, and they persist throughout life (Hopkins and Smith, 1993). Righting reactions support the vertical position of the head, alignment of the head and trunk, and alignment of the trunk and pelvis. These reac- tions are essential for the effective control of assistive tech- nologies. Hopkins and Smith also list nine righting reactions. One reaction that can interfere with assistive tech- nology use is the positive supporting reaction, which is elicited by pressure on the toe pads or ball of the foot. The pressure from the footrest of a wheelchair, for example, can elicit this reaction. Increased extensor tone of the lower extremities follows simultaneously with contraction of the flexor muscles. The result is strong extension of the legs, which affects upright posture.

Equilibrium reactions provide balance when the center of gravity is disturbed, such as by leaning to one side. As the nervous system matures, equilibrium reactions serve to regain balance. These reactions include the counterrotation

P A R T I Introduction and Framework 83

of the head and trunk away from the direction of a displace- ment of gravity (e.g., by leaning) and the use of the extrem- ities to gain balance by abduction. Hopkins and Smith (1993) describe 12 equilibrium reactions.

Muscle tone is defined as the resistance to stretch pro- vided by neural activity, viscoelastic properties of muscle and joints, and sensory feedback to the CNS (Brooks, 1986). Normal muscle tone is high enough so that the individual can resist gravity and low enough to allow for movement (Bobath, 1978). Tone varies with age, level of activity, stress, and other factors. Muscle tone in infants is generally decreased, or hypotonic, and infants begin to develop more normal tone as the nervous system develops. As people age, the amount of tone generally decreases for many reasons, including changes in muscle fibers, sensory receptors, and CNS function (Farber, 1991).

Disabilities can also lead to changes in muscle tone. Depending on the level of damage to the nervous system, impaired muscle tone can include flaccidity, spasticity, and rigidity. A reduction in normal muscle tone is referred to as flaccidity or hypotonicity. When muscle tone is increased, it is referred to as hypertonicity or spasticity. Several types of disorders can result in spasticity. Increased muscle tone is often accompanied by exaggerated reflexes and imbalances between the antagonistic muscle pairs controlling joints. With rigidity there is an increase of muscle tone in both the antagonist and agonist muscles at the same time, resulting in resistance to passive range of motion throughout the range and in any direction (Undzis, Zoltan, and Pedretti, 1996). It is possible for a person to exhibit a mixture of types of mus- cle tone and for the tone to fluctuate throughout the course of a day. This fluctuation has a direct consequence on effec- tor use and therefore on the control of assistive technologies.

Trauma to or disease of the CNS that results in abnormal muscle tone, the presence of primitive reflexes, or abnormal righting or equilibrium reactions affect the individual’s abil- ity to maintain a stable upright posture and perform smooth, coordinated movements. When an individual does not have the ability to stabilize the body, assistive technolo- gies can be used externally to obtain balance and functional positioning (discussed in Chapter 6). Lack of coordinated volitional movements may dictate the use of specialized con- trols that are enlarged or positioned in locations of maximal control (see Chapter 7).

Characterization of Effector Movements

The movements of effectors can be characterized in several ways, as listed in Table 3-7. By defining the resolution, range, strength, and flexibility for an anatomical site, we can relate these to the skills required for the use of control interfaces.

Resolution. Resolution is used to define the degree of fine control, and it describes the smallest separation between

two objects that the effector can reliably control. For exam- ple, the spacing of individual keys on a keyboard requires relatively fine motor control and an effector with good reso- lution. Alternatively, a 6-inch diameter single switch used to turn on a toy requires much lower resolution on the part of the effector. All the components of effector use that we have described contribute to the generation of high-resolution fine movements.

Range. The maximal extent of movement possible is range. Some tasks require large range and others require small range. For example, the use of push rims on a manual wheelchair requires a relatively large range of movement, whereas the use of a computer mouse requires a relatively small range. The combination of resolution and range allows us to define the workspace of the effectors. These are both affected by disease or injury. For example, contractures, a shortening of the muscles and tendons that limits joint range of motion, may occur as a result of increased tone.

Strength. Another measure of effector performance is strength of movement. Designers of assistive technology systems must take into account the strength of the effector that is being considered for control of the system. In gen- eral, the upper extremities function best when precision and control are required, and the lower extremities are best suited for power and strength. Control of assistive technol- ogy systems may require that a minimal level of strength, as reflected by the force required to activate a control inter- face, be available. Even if the necessary resolution and range are available, there may be insufficient strength to activate the control.

In some disabilities, strength is significantly reduced (or absent). For example, paralysis resulting from a spinal cord injury prevents the use of certain effectors, depending on the level of the injury (Table 3-8). In this case the major goal is to find an effector that is not paralyzed; head or chin control may be required, rather than a control interface activated by hand function. Partial paralysis or paresis is a muscle weakness that makes it difficult to move but does not pre- vent movement as paralysis does. In this case the assistive

84 C H A P T E R 3 Disabled Human User of Assistive Technologies

Effector Characteristics

Effector Resolution Range Strength Versatility

Fingers High Small Low Very high Hand Moderate Moderate Moderate Moderate Arm Low Large Large Low Head Moderate Moderate Moderate High Leg Low Moderate High Low Foot Moderate Large High Low Eyes High Small NA Moderate

NA, Not applicable.

TABLE 3-7

technology control interfaces must be modified to accom- modate for reduced effector capabilities. For example, an adapted door handle could be used to require less force to be applied to turn the doorknob. In diseases such as muscular dystrophy, fine control is often available but muscle weak- ness results in very low levels of strength, which may lead to restricted movement over large distances, but fine move- ments such as those required for a contracted keyboard or a short-throw joystick may be possible.

It is also possible that strength is too great for adequate control. This situation often occurs when the foot is used for fine control such as typing on a keyboard. However, exces- sive strength is not restricted to the lower extremities. Spastic movements are poorly controlled, and they often lead to force in excess of that required for control. Because many control interfaces, such as joysticks, are designed for normal upper extremity levels of force, the excessive forces generated by spastic movements can result in damage to the assistive technology system, as well as to poor performance.

Endurance. ATPs are also interested in the ability of an individual to sustain a force. In contrast to strength, which is an indicator of the maximal force that can be exerted by an effector, endurance refers to the ability to sustain a force

and to repeat the application of a force over time. In other neuromuscular disabilities, such as myasthenia gravis, the problem is one of fatigue, and initial strength may be within a normal range. However, as the individual repeats a move- ment, there is a continual decrease in performance until total fatigue occurs. Aspects of the assistive technology sys- tem design can minimize the effect of fatigue in several ways. First, the interface between the human and the device can be designed to minimize the amount of fatigue by requiring low energy expenditure. The device can also be designed so that it is flexible and reduces the amount of effort as the person tires. An example of the first approach is a joystick for a wheelchair, which requires very little travel and small force. An example of adaptation to fatigue is a variable scanning rate so that when the user is fresh, the scanning is rapid (and selections can be made quickly), but when the person tires, the scan rate slows down to accom- modate. The slowdown could be automatically triggered by erroneous entries or manually selected by the user or an attendant. These approaches may be necessary to allow continued functional performance in the presence of fatigue. The careful consideration of the strength and endurance available to move an effector is crucial to the successful application of assistive technology systems.

P A R T I Introduction and Framework 85

Motions and Functions Available at Different Levels of Spinal Cord Injury

Level of Injury Active Motion Available* Possible Functions

C3 Neck motion Unable to perform personal care Chin control Directs others in transfers, personal care

Uses mouth or chin control for assistive technologies, ventilator on wheelchair C4 Neck motion Same as C3 except:

Shrugs shoulder No ventilator Shoulder switch available

C5 Some shoulder motions Assistance for bathing/dressing, bladder/bowel care, transfer Flex elbow, no extension Uses mobile arm support for feeding, hygiene, grooming, writing, telephone

(must be set up by attendant) Uses chin or mouth control for assistive technologies Can propel manual wheelchair short distances with hand rim projections

C6 Wrist extension Independent transfer, dressing, personal hygiene Forearm pronation Manual wheelchair possible with adapted rims, hand splints for writing, Full shoulder motions feeding, hygiene, grooming, telephone, typing

C7 Wrist, elbow, shoulder motions; Independent sitting no finger grasp Drive with adapted controls; uses hand splints for manipulation

C8 No intrinsic hand muscles; limited Limited hand grasp with splints sensation in the fingers

T1 Paralysis of intrinsic hand muscles; Weak unaided grasp limited flexibility of hand

T2-T12 Full use of upper extremities; Manual wheelchair; may use reachers; trunk supports required for higher levels increasing lower extremity function at lower levels; increasing trunk control at lower levels

Modified from Adler C: Spinal cord injury. In Pendleton HM, Schultz-Krohn W, editors: Pedretti’s occupational therapy: practice skills for physical dysfunction, ed 6, St Louis, 2006, Mosby. *At each lower level, all the functions of higher levels are available plus those listed for the given level.

TABLE 3-8

Versatility. Some effectors are capable of being used for a variety of tasks and in a variety of different ways for the same task. This characteristic is called versatility. For example, both the hand (fingers) and foot (toes) can be used to press a key or switch. However, the hand can also be used to grasp a handle (e.g., a joystick). Thus the hand is more versatile than the foot. The higher the versatility, the more options provided for the use of the effector to control an assistive device, which is directly reflected in our choice of control interfaces (see Chapter 7) and in the overall design of the human-technology interface.

SUMMARY

The emphasis of this chapter has been on the human oper- ator of assistive technologies. The use of the basic informa- tion processing model shown in Figure 3-1 allows us to describe the many components that underlie human per- formance. This model is also used in succeeding chapters as we discuss specific assistive technology systems. The next chapter explores the assessment of these areas of perform- ance for the purpose of matching assistive technologies to the skills and needs of persons with disabilities.

86 C H A P T E R 3 Disabled Human User of Assistive Technologies

Study Questions

1. Distinguish between sensation and perception. 2. Assume that you determine the total reaction time for an

upper-arm reaching task. Referring to Table 3-6, how would you expect the various components of this total to change (i.e., increase or decrease) given the following conditions: (a) muscular dystrophy, (b) spinal cord injury at the T2 level, (c) traumatic brain injury, (d) cerebral palsy, (e) Hansen’s disease (loss of peripheral sensation)?

3. What is the difference between visual tracking and visual scanning? How do the oculomotor mechanisms that underlie them differ?

4. What is visual accommodation, and how can it affect assistive technology use?

5. What are the three major characteristics that can be changed to increase visual input?

6. If you knew that a person with whom you were work- ing had a severe peripheral visual loss, what color of stimulus would you use to try to maximize visibility (refer to Figure 3-3)?

7. If a person is reported as having a 40-dB hearing loss at 2000 Hz, what was the actual intensity of sound applied to the ear (refer to Figure 3-6)?

8. How is the degree of self-produced locomotion related to integration of visual and vestibular sensory function? Relate this to dependent and independent wheeled mobility.

9. Explain why prism glasses experiments produce the results they do, including the effects on kinesthetic perception.

10. Assume that you are trying to develop a word process- ing program for use as an augmentative writing system. How would your design differ for a preoperational, con- crete operational, and formal operations person? Focus on the user interface (screen commands, loading files, etc.) to the system and special features that you would or would not include. Also include the method you would use to introduce the program to each group.

11. Is motor capability necessary for the development of cognitive skills? If yes, how much capability is required? Explain and justify your answer.

12. What are the major notions involved in self-concept? 13. How is self-concept related to the physical abilities and

attributes of the assistive technology user? 14. List and describe the stages of loss typically experienced

by a person who has sustained an injury or disease that results in permanent disability.

15. How is the concept of self-protection related to the acquisition and use of assistive technologies?

16. How can difficulties in self-concept or self-protection lead to abandonment of assistive technologies?

17. What are the six factors that affect motivation? How can each of these be incorporated into an assistive tech- nology system? Give an example for each factor.

18. What are the three types of memory distinguished on the basis of time?

19. What is the difference between recognition and recall? How does each apply to assistive technology device use?

20. What are the five basic elements of language? Distinguish between speech and language.

21. What is the difference between problem solving and decision making?

22. Design a flow chart similar to Figure 3-7 for a program of your choice. Assume that the user has short-term memory deficits that make it difficult to follow a sequence of steps.

23. Explain the meaning of the solid and dashed curves in Figure 3-9. What type of curves would you expect if the individual lacked good trunk support to each side?

24. What are the implications of a decrease in motor path variability on assistive technology use?

25. Distinguish between range and resolution for an effector system.

26. How does the age at which an individual is introduced to assistive technology influence acceptance and suc- cessful use of assistive technologies?

27. How does the age at which an individual is introduced to assistive technologies relate to the possibility of abandonment of those technologies?

P A R T I Introduction and Framework 87

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88 C H A P T E R 3 Disabled Human User of Assistive Technologies

PA R T 2

Service Delivery in Assistive Technologies

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Delivering Assistive Technology Services to the Consumer

Chapter Out l ine

PRINCIPLES OF ASSISTIVE TECHNOLOGY ASSESSMENT AND INTERVENTION

Assistive Technology Assessment and Intervention Should Consider All Components of the HAAT Model: Human, Activity, Assistive Technology, and Context

Assistive Technology Intervention Is Enabling Assistive Technology Assessment Is Continuous

and Deliberate Assistive Technology Assessment and Intervention Require Collaboration and a Consumer-Centered Approach

Assistive Technology Assessment and Intervention Require an Understanding of How to Gather and Interpret Data

Quantitative and Qualitative Measurement Norm-Referenced and Criterion-Referenced Measurements Methods for Gathering and Interpreting Information

OVERVIEW OF SERVICE DELIVERY IN ASSISTIVE TECHNOLOGY

Referral and Intake Initial Evaluation Needs Identification Skills Evaluation: Sensory Evaluation of Functional Vision Evaluation of Visual Perception Evaluation of Tactile Function Evaluation of Auditory Function Skills Evaluation: Physical Identifying Potential Anatomical Sites for Control Selecting Candidate Control Interfaces Comparative Testing of Candidate Control Interfaces Skills Evaluation: Cognitive Skills Evaluation: Language Matching Electronic Device Characteristics to the User’s Needs and Skills

Human/Technology Interface

The Processor Environmental Interface Activity Output Physical Construction Evaluating the Match Between Characteristics and

the Consumer’s Skills and Needs Effects of Errors in Assistive Technology Systems Decision Making Recommendations and Report

IMPLEMENTATION Ordering and Setup Delivery and Fitting Facilitating Assistive Technology System Performance Training Performance Aids Written Instructions

FOLLOW-UP AND FOLLOW-ALONG

EVALUATING THE EFFECTIVENESS OF ASSISTIVE TECHNOLOGY SERVICES AND SYSTEMS

Overview Measuring Clinical and Functional Outcomes Functional Independence Measure User Satisfaction as an Outcome Measure Canadian Occupational Performance Measure Quebec User Evaluation of Satisfaction With Assistive

Technology Assistive Technology Abandonment Quality of Life as an Assistive Technology Outcome Measure Health-Related Quality of Life Psychosocial Impact of Assistive Devices Scale Matching Person and Technology Model Relationship of Outcome Measures to the Human Activity Assistive Technology Model

91

C H A P T E R 4

Service delivery is the provision of hard and soft assis-tive technologies to the consumer. Chapter 1 delin-eated the components of the assistive technology industry, which has at its core the consumer and service delivery programs. This chapter describes the process by which the consumer obtains assistive technology devices and services. Chapter 2 described a model that is used as the basis for assistive technology assessment and intervention (human activity assistive technology [HAAT] model) and discussed the principles of assistive technology system design. This chapter builds on the HAAT model by delin- eating systematic methods of assessment and intervention that help the assistive technology provider (ATP) define the components of the model and integrate them into an effective

assistive technology system for each individual consumer. The intrinsic enablers of the human and his or her relation- ship to the use of assistive technologies, as discussed in Chapter 3, provide the foundation for the discussion of eval- uation of consumer skills in this chapter.

To effectively provide these services to the consumer, the ATP should be knowledgeable in the following areas:

1. The principles related to assessment and interven- tion and methods of gathering and interpreting information

2. The service delivery practices used to determine the consumer’s needs, evaluate his or her skills, recom- mend a system, and implement the system

92 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

Conclusions

SUMMARY

APPENDIX 4-1A: SAMPLE OF A WRITTEN QUESTIONNAIRE

APPENDIX 4-1B: ASSESSMENT FORMS

Key Terms

Assessment Client-Centered Practice Criteria for Service Criterion-Referenced Measurement Device Characteristics Expert Systems Functional Performance Measures Follow-Along

Follow-Up Health-Related Quality of Life Implementation Phase Needs Identification Norm-Referenced Measurements Operational Competence Outcome Measures Performance Aid

Qualitative Measurement Quality-of-Life Measures Quantitative Measurement Referral and Intake Strategic Competence Technology Abandonment User Satisfaction User Satisfaction Measures

Learning Objectives

On completing this chapter, you will be able to do the following:

1. Describe principles related to assessment and intervention in assistive technology service delivery 2. Describe the methods used to gather and analyze information during assistive technology assessment and

intervention 3. Understand the relationship between the consumer’s life roles and performance areas and his or her needs for

assistive technology 4. Identify and describe each of the steps in assistive technology service delivery 5. Discuss the matching of device characteristics to consumer needs and skills 6. Understand the need for training and how to develop effective programs 7. Define outcomes as related to assistive technology 8. Understand why outcomes in assistive technology need to be measured 9. Discuss the principles of outcome measurement and their relationship to service delivery and system effectiveness

10. Understand how measurement of outcomes in related disciplines can contribute to knowledge and development of assistive technology outcome measurements

11. Understand the unique outcomes measurement needs of the field of assistive technology 12. Describe the primary outcome measurement tools developed for outcome assessment in assistive technology service

delivery programs

3. The measurement of outcomes of the assistive tech- nology system that indicate whether the identified goals have been achieved

4. The identification and attainment of funding for services and equipment

In this chapter and in Chapter 5 general principles and practices related to each of these areas are presented.

PRINCIPLES OF ASSISTIVE TECHNOLOGY ASSESSMENT AND INTERVENTION

The assistive technology intervention begins with an assessment of the consumer. Through this assessment, information about the consumer is gathered and analyzed so that appropriate assistive technologies (hard and soft) can be recommended and a plan for intervention developed. Information is gathered regarding the skills and abilities of the individual, what activities he or she would like to per- form, and the contexts in which these activities will be per- formed. The assessment also yields information regarding the consumer’s ability to use assistive technologies. On the basis of the assessment results, a plan for intervention is developed. This plan includes implementation of the sys- tem, follow-up, and follow-along. Basic principles that underlie assessment and intervention in assistive technology service delivery are listed in Box 4-1.

Assistive Technology Assessment and Intervention Should Consider All Components of the HAAT Model: Human, Activity, Assistive Technology, and Context

Often assistive technology assessment focuses on the assis- tive technology only, which can lead to later rejection or

abandonment of the technology. One way to reduce the probability of abandonment or misuse is to consider system- atically all four parts of the HAAT model. Needs and goals are often defined by a careful consideration of the activities to be performed by the individual. However, it is rare that the activity will be performed in only one context, so it is important to identify the influence of the physical, sociocul- tural, and institutional elements in the contexts in which the activities will be performed (see Chapter 2). Thus the care- ful evaluation of the activities to be performed and the con- textual factors under which that performance will occur are key to success. Once the goals have been identified, an assessment of the skills and abilities of the human operator (the consumer) must be identified. Only after consideration of these three components (activity, context, and human) can a clear picture emerge of the assistive technology requirements and characteristics. The assessment process must also include an assessment of the degree to which these characteristics match the consumer’s needs. Chances of suc- cess in implementation of an assistive technology system are enhanced by attention to all four parts of the HAAT model during the service delivery process.

Assistive Technology Intervention Is Enabling

The primary purpose of assistive technology intervention is not remediation or rehabilitation of an impairment but pro- vision of hard and soft technologies that enable an individ- ual with a disability to be functional in activities of daily living. This principle places the focus on functional out- comes. Through the application of the HAAT model we can develop goals for the assistive technology intervention, and these goals ultimately are used to measure the functional outcomes of the intervention. Approaching intervention from this perspective requires that the ATP determine the individual’s strengths and capitalize on them instead of focusing on deficits or impairments. For example, in func- tional activity of typing, in a rehabilitation approach the goal would be to improve hand and finger control sufficiently to allow for typing, with the intervention focusing on exercises and activities for the fingers and hands. From an assistive technology perspective, however, the objective becomes enabling the person to perform the functional activity of typing regardless of how it is done. The impairment in the hands and fingers that causes the disability is not necessar- ily addressed. The disability of being unable to type is what is addressed in the assistive technology approach. Through the use of assistive technology, alternative approaches to using the fingers for typing are considered, such as using a mouthstick, head pointer, or a speech recognition system instead of the hands.

This focus on function does not mean an individual’s potential for improvement is ignored.The parallel interventions model (Angelo and Smith, 1989; Smith, 1991) demonstrates

P A R T II Service Delivery in Assistive Technologies 93

BOX 4-1 Principles of Assessment and Intervention in Assistive Technology

● Assistive technology assessment and intervention should consider all components of the HAAT model: the human, the activity, the assistive technology and the context.

● The purpose of assistive technology intervention is not to rehabilitate an individual or remediate impairment but to provide assistive technologies that enable an individual to perform functional activities.

● Assistive technology assessment is continuous and deliberate. ● Assistive technology assessment and intervention require

collaboration. ● Assistive technology assessment and intervention require

an understanding of how to gather and interpret data.

94 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

how technology can be used to promote the dual objectives of enabling function and improving an individual’s skill level. In one track, assistive technologies are provided that are based on the consumer’s current skills and needs and that maximize function. Simultaneously, a second track provides intervention that focuses on improving skill level to mini- mize the reliance on technology. Some individuals who have a severe physical disability may never have had the opportu- nity to develop their motor skills, and training to develop these skills can take months or years (Cook, 1991). A com- mon example is an individual whose evaluation shows that he or she is able to use the head to activate a single switch to make simple choices on a computer. With training and a period of experience in using this switch, head control may improve to the point where the individual can use a light beam positioned on the head to make direct choices with a dedicated communication device. The latter means of con- trol would more quickly provide access to choices on a device and would be much less demanding cognitively.

Assistive Technology Assessment Is Continuous and Deliberate

Although assessment is typically considered a discrete event in the direct service delivery process, it is actually a continu- ous process. Assistive technology assessment entails a series of activities linked together and undertaken over time. The activities that occur and the decisions that are made during the intervention are deliberate rather than haphazard. Information is gathered and decisions are made from the moment of the initial intake referral through follow-along.

The ATP re-evaluates progress toward the goals of the intervention plan and makes necessary revisions. For example, during training, observation may reveal that the consumer can access the control interface more effectively if it is positioned at an angle instead of flat. As decisions are implemented, their influence is continuously assessed and revisions are made to the intervention. The ideas of client-centered practice (Canadian Association of Occupational Therapists, 2002) highlight the importance of involving the client at all stages of assessment, from the initial framing of the activities in which the client wishes to engage to the recommendation of an assistive technology system. The client refers to the individual and others in the environment such as family and caregivers (Canadian Association of Occupational Therapists, 2002). Assessment continues not only while the consumer is actively involved in the service delivery process but also potentially throughout the consumer’s life. Because many individuals have life-long disabilities, they will be in need of assistive technology throughout their lives. It is important not only to recommend assistive technology that enables the individual today but also to predict the technol- ogy that will be necessary to enable the individual in the future. The components of the HAAT model change over

each individual’s lifetime. Changes may occur in the individ- ual’s skills and abilities, life roles, and goals; the capabilities of technology; and the context in which the assistive tech- nologies are used. By using the HAAT model as a frame- work, the ATP can predict some of these changes and plan for the consumer’s future technology needs.

Assistive Technology Assessment and Intervention Require Collaboration and a Consumer-Centered Approach

Given the nature of assistive technology and its influence on the consumer’s activities of daily living, it is essential that the assessment and intervention be a collaborative process. McNaughton (1993) defines a collaborator as “one who works with another toward a common goal” (p. 8). Furthermore, she states that collaboration requires that (1) all participants be equal partners, (2) a problem-solving attitude be shared by all participants, (3) there be mutual respect for each other’s knowledge and the contributions each person can make as opposed to the titles he or she holds, and (4) each partici- pant have available the information necessary to carry out his or her role (McNaughton, 1993).

Frequently, assistive technology services are provided through consultation, in which the ATP is called into a sit- uation on a limited basis to specifically address the assistive technology needs of the consumer. There may be several people already involved with the consumer, including family members, teachers, vocational counselors, employers, thera- pists, and representatives from the funding source. The assistive technology assessment and intervention is more successful when these significant others are identified and involved at the beginning of the process.

There is a delicate balance between the opinion and “expert- ise” of the ATP (based on technical knowledge and experience with a variety of people) and the opinion and “expertise” of the consumer and family relating to the specific needs and goals of the person. The role of the ATP is to educate the con- sumer of the choices available so that the consumer can make decisions related to the assistive technology in an informed manner. The challenge for the ATP is to do this without unduly influencing the client’s choice. The value of this approach is that the consumer and the ATP inform each other throughout the process and develop a shared respon- sibility for the outcome. This approach has been referred to as the “educational model” of intervention (as opposed to the “expert” and “consumer-driven” models, which take one extreme position or the other). Lysack and Kaufert (1999) describe this process and its benefits.

The ATP should initiate the collaborative process by identifying significant others as a part of the intake referral phase. For example, Jerry, who has a developmental disabil- ity, lives in a small group home. During the intake, the ATP discovers there are several key people who need to be

P A R T II Service Delivery in Assistive Technologies 95

involved in the assistive technology intervention for Jerry: staff at his home, staff at the day program he attends, an occupational therapist who consults with his residential program, his caseworker at the department of developmen- tal services, and his parents, who live out of town. Each of these individuals is invited to participate in the initial assessment and decision-making process. Different partic- ipants will be working with the consumer to accomplish different goals. Communication among the collaborators regarding their respective goals for the consumer is critical. It is important to identify the ways in which the goals of the assistive technology intervention can be accomplished without interfering with other goals. Sometimes compro- mises need to be reached. For example, two professionals working with the consumer may be focusing on different goals, and compromises may need to be made by all parties in working toward these interdependent goals. One thera- pist may be working with a child on improving the strength in his or her neck muscles to improve head con- trol, whereas the ATP’s goal may be to support and posi- tion the head in an upright position to prevent deformity and allow optimal position for functional activities. The success of the assistive technology system depends on coordination and teamwork among all the individuals involved with the consumer.

Beukleman and Mirenda (1998) discuss the importance of building consensus among the user, family members, and other team members. Negative consequences, such as a lack of vital information for intervention, lack of “ownership” of the intervention resulting in poor follow-through with the recommendations, and distrust of the service provider, may result if the process of consensus building is not begun dur- ing the initial assessment. Initiating this process early helps to avoid problems in the future with regard to the accept- ance and use of a device.

Assistive Technology Assessment and Intervention Require an Understanding of How to Gather and Interpret Data

It is both possible and desirable to measure human perform- ance, and much of what is described in this chapter is directed toward that end. In assistive technology service delivery we need to be careful that we know what we are measuring. In some cases, as in determining the effective- ness of our service delivery process and outcomes, we want to measure the performance of the entire assistive technology system. Because this system has been defined to be the four components of the HAAT model (human, activity, context, and assistive technology), measurements and outcomes that apply to the entire system must be devel- oped. In other cases (e.g., during an initial assessment) human performance rather than system performance needs to be measured. Measuring human performance can be

general or task specific (Sprigle and Abdelhamied, 1998). An individual’s general abilities are measured when separate components of the sensory, perceptual, physical, and cogni- tive systems, such as range of motion, sensation, strength, tone, or memory, are evaluated. Task-specific measurement involves the evaluation of the individual’s functional skills. The ability of the person to complete a functional task, such as entering text into a computer document, requires a level of skill that combines physical, sensory, and cognitive abili- ties. In this case clear objectives must be established for each task, a clinical standard to be applied must be devel- oped, and then measures that evaluate the performance must be developed.

In this section we focus on the principles associated with measurement in assistive technology service delivery. These include the purposes, types, standards, and methods of measurement.

Quantitative and Qualitative Measurement. Information gathered by the ATP throughout the assistive technology intervention can be by either quantitative measurement or qualitative measurement. The philosophies of qualitative measures and quantitative meas- ures are quite different. Quantitative measures assign a number to an attribute, trait, or characteristic (Nunnally and Bernstein, 1994). The assumption of quantitative meas- ures is that the construct of interest can be measured in some meaningful way. For example, a test can be constructed that measures the joint range of motion (the construct) that an individual has available to control a computer access device. Joint range is expressed as degrees of motion and a common understanding exists regarding what is meant when a spe- cific joint range of motion is described. Here the construct can be assigned a number that is meaningful to individuals using and interpreting the test. Alternatively, a test can be constructed that intends to measure boredom. It is pos- sible to develop a scale and have individuals rate their bore- dom on a four-point scale (for example). But what does a score of 4 mean on such a scale? We can assign a number on a scale but it is difficult to interpret the meaning of that number.

Qualitative assessments assume that each individual has a different experience and that it is important to provide the opportunity to capture that experience. There is no attempt to measure a particular construct. Rather, the purpose is to describe and understand the user’s experience with the tech- nology. Qualitative assessments may include observation, either directly or by videotape or interview with the client and others. Qualitative assessments often capture those experiences that cannot be directly quantified or for which quantification holds little meaning. They provide the client with the opportunity to identify issues, experiences, or goals that may not be previously identified on a quantitative measure.

Both qualitative and quantitative assessment formats are important in the AT assessment process and for evaluation of the outcomes of AT use. Quantitative measures allow comparison of experiences of a large number of individuals and a well-constructed instrument is essential in building evidence to support the efficacy of AT use. Qualitative methods provide a rich description of the experiences of AT use, which may not be readily apparent from the use of quantitative instruments alone. Together these methods can provide strong support for AT use, both on an individual and collective basis.

Norm-Referenced and Criterion-Referenced Measurements. Two commonly used standards are avail- able for measuring performance (for both the human and the total system): norm referenced and criterion referenced. In norm-referenced measurements the performance of the individual or system is ranked according to a sample of scores others have achieved on the task. Norm-referenced measures usually produce a percentile rank, a standardized score, or a grade equivalent that indicates where the individ- ual stands relative to others in the representative sample (Witt and Cavell, 1986). When selecting a norm-referenced test for use, it is important to review how the norms were developed. Norms need to be relevant to the population for which the instrument is being used. They need to be recent and representative (Wiersma and Jurs, 1990). In other words, the characteristics of the sample used to develop the norms must be similar to those of the client group for which

the assessment is being used. The items that form the instrument need to be relevant to the client group. For example, assessing visual-perceptual skills by using blocks is not relevant for most adults. Similarly, use of outdated ques- tions or materials will not give an accurate picture of the client’s abilities. For example, testing keyboarding skills on a typewriter will give some information on keyboarding skills but does not cover the full range of skills required to use a computer (Miller Polgar, 2003). An alternative way to assess human or system performance is to rate the perform- ance according to a specified criterion or level of mastery, which is referred to as criterion-referenced measure- ment, and the person’s own skill level in using the system is used as the standard. As an example of this approach, Jagacinski and Monk (1985) evaluated joystick and head pointer use by young adult nondisabled subjects. They found that skill in using these devices is acquired with some difficulty over many trials.The criterion used was whether the individual’s performance (time to move to target) did not change by more than 3% over a period of 4 consecutive days (Figure 4-1). In Figure 4-1, the horizontal axis represents the elapsed practice time and the vertical axis represents how quickly the person has been able to use the joystick or head pointer to move to a target. The horizontal dotted line is the final level of performance and serves as the criterion of performance. Using this criterion, they found that joy- stick use required 6 to 18 days and head pointer use required 7 to 29 days of practice to reach the criterion level of performance.

96 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

Asymptote

5 10 15 20

S pe

ed o

f R es

po ns

e

Time (days)

Figure 4-1 Speed of response to reach a target as a function of days of training. The horizontal axis is days of training. The vertical axis represents the speed to reach the target. The dotted horizontal line is the speed as performance levels off. This is used as the criterion for performance.

When the criterion-referenced approach to measurement is used, two desirable goals are accomplished. First, the assessment of progress is based on the person’s unique set of skills and there is no attempt to relate this performance to a normalized standard. In this example, the two alternative ways of accomplishing the same task (joystick and head pointer) are compared to determine which method is likely to result in a higher skill level. The second goal is accom- plished by using the person’s own performance as a standard for measuring progress. Goal attainment scaling (King et al, 1999) is one standardized process of developing criteria that are specific to the client and task that are then applied to evaluate outcomes.

Methods for Gathering and Interpreting Information. There are several methods used to gather and interpret quantitative and qualitative information about the con- sumer: (1) collection of the initial database, (2) interview procedures, (3) clinical assessment, and (4) formal assessment procedures (Dunn, 1991). Often, more than one method is used to gather information about the same aspect of a con- sumer’s skills, the context, the activity, or the use of assistive technology. For example, information on an individual’s hand function can be collected through each of these methods. The use of multiple sources of information is illustrated by Sam, a 22-year-old man with quadriplegia secondary to a complete C6 lesion of the spinal cord, who is being evalu- ated for his ability to access a computer.

Information collected for the initial database may include the reason for referral, medical diagnosis, and educational and vocational background information. This information is collected during the referral and intake phase of the service delivery process; its purpose is to provide preliminary data for planning the assessment. Sam’s medical diagnosis is complete quadriplegia at the C6 level. If we refer to a text describing the effects of spinal cord injury at the C6 level on arm function (see Table 3-8), we expect Sam to have scapu- lar movements, shoulder flexion, elbow flexion, and wrist extension but to lack finger flexion and extension. Most medical histories do not provide information on the con- sumer’s assets and functional abilities. In some cases we may unintentionally limit the consumer’s potential if we fail to look beyond the expectations we have acquired on the basis of the medical diagnosis. As Christiansen (1991) points out, a medical diagnosis may provide guidelines for the assess- ment and expectations regarding the nature of the con- sumer’s impairments, but it is inadequate for planning intervention.

The interview, another way to collect information, can occur at different points in the service delivery process. Typically, an initial interview takes place during the needs identification phase as a means of gathering information regarding the consumer and his or her needs. It is important that the consumer, family members, rehabilitation or education

professionals, and other care providers be interviewed. In Sam’s case, during the initial interview his goals and his particular needs related to using a computer are determined. The tasks with which he has difficulty performing are identified. Finding out whether Sam currently uses any adap- tive equipment, or has in the past, to complete functional tasks also provides valuable information about his hand function. For example, Sam is able to sign his name by using an adapted splint to assist with grasping the pen, but it is difficult for him to write and he tires quickly. This difficulty has led him to pursue the use of a computer to facilitate tak- ing notes at school and completing homework assignments. Another stage in which the interview is important is follow- up. At this stage, interviewing the consumer or caregivers provides valuable information on whether the device is being used and how. It is important that the ATP develop the ability to conduct interviews so that useful information is gathered.

Formal assessment procedures are administered in a pre- scribed way and have set methods of scoring and interpreta- tion. Therefore, they can be duplicated and analyzed. Through formal assessment procedures, Sam’s arm and hand abilities can be quantified. For example, Sam’s muscle strength in his upper extremities can be evaluated by per- forming a manual muscle test (Daniels and Worthingham, 1986). Formal assessments should use standardized tests whenever possible. The ATP who uses such tests should evaluate the instrument development and psychometric properties to determine whether they are applicable to the client population and that the interpretation of the scores will be meaningful. Frameworks exist that guide a clinician’s critique of an evaluation (e.g., Miller Polgar and Barlow, 2002). These frameworks identify aspects of test construc- tion, psychometrics, and clinical utility that are important considerations of an instrument’s usefulness in a given situation. Clinical assessment techniques involve skilled obser- vation of the consumer and are used throughout the assess- ment and intervention process. The ATP may structure these techniques so that a series of steps is followed to determine specific skills or they may be intentionally left unstructured to see what takes place. Observation can be done during a simulated task in a clinic setting or in a con- text familiar to the consumer (e.g., classroom or work- place). Through skilled observation during the structured task of a series of typing tests, it may be observed that Sam’s typing speed and accuracy improve when he stabi- lizes himself with his left forearm and types with his right hand. Observation complements information obtained from standardized tests.

All these considerations lead to one very important con- clusion: In the application of assistive technology systems, success is largely the result of the combined efforts of knowl- edgeable and competent clinicians who, in collaboration with informed consumers and caregivers, make decisions on the

P A R T II Service Delivery in Assistive Technologies 97

basis of both specific knowledge and experience. The com- plexity of the total system, including the diversity of the individual and of disabilities, technologies, and contexts of use, dictates that, when an assistive technology device is designed, best practice is often a matter of using clinical rea- soning combined with results of established assessments.

OVERVIEW OF SERVICE DELIVERY IN ASSISTIVE TECHNOLOGY

Regardless of the type of service delivery model (see Chapter 1), there is a basic process by which delivery of services to the consumer occurs. Figure 4-2 illustrates the steps involved in this intervention process. The first step is referral and intake. At this point, the consumer, or someone close to him or her, has identified a need for which assistive technology intervention may be indicated and contacts an ATP to make a referral. The service provider gathers basic information and determines whether there is a match between the type of services he or she provides and the identified needs of the consumer. Funding for the services to be provided is also identified and secured at this stage. Once the criteria for intake have been met, the evaluation phase begins. A more detailed specification of the consumer’s assistive technology needs is the first step in this phase, which is referred to as needs identification. After a thorough identification of the con- sumer’s needs, the consumer’s sensory, physical, and cogni- tive skills are evaluated. Technologies that match the needs and skills of the consumer are identified, and a trial evalu- ation of these technologies takes place. The evaluation results are summarized and recommendations for technolo- gies are made on the basis of consensus among those involved. These findings are summarized in a written report, which is used to justify funding for the purchase of the assistive technology system.

When funding is secured, the consumer proceeds with the intervention in the implementation phase. At this phase, the equipment that has been recommended is ordered, modified, and fabricated as necessary, set up, and delivered to the consumer. Initial training on the basic oper- ation of the device and continuing training of strategies for using the device also take place during this phase.

Once the device has been delivered and training has been completed, whether the system as a whole is functioning effectively must be determined. This step normally occurs during the follow-up phase, in which it is determined whether the consumer is satisfied with the system and whether the goals that have been identified are being met. The follow-up phase actually closes the loop by putting in place a mechanism by which regular contact is made with the consumer to see whether further assistive technology services are indicated. When further AT services are required,

the referral, intake, and implementation phases are repeated. Building this final phase into the service delivery process ensures that the consumer’s needs are considered throughout the life span. A more in-depth look at each of these steps follows.

98 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

Referral and Intake

Initial Evaluation

Recommendations and Report

Implementation

Order and Setup Delivery and Fitting Training

Follow-up

Maintenance Repair As Needed

Follow-along

Reevaluate Maintenance Repair As Needed

Indicates that at this point in the process, funding typically needs to be requested in order to continue.

Needs Identification Skills Evaluation Sensory Physical Cognitive Language Device Characteristics

F

F

F

F

F

Figure 4-2 Steps in the service delivery process.

Referral and Intake

The purpose of the referral and intake phase is to (1) gather preliminary information on the consumer, (2) determine whether there is a match between the needs of the consumer and the services that can be provided by the ATP, and (3) ten- tatively identify services to be provided (Gaster, 1992).

The consumer, or the person making the referral on the consumer’s behalf, recognizes a need for assistive technol- ogy services or devices, which triggers the referral to the ATP. These identified needs are called criteria for service, and they define the objectives for the intervention. A third party involved in the referral, such as a state vocational rehabilitation agency, will have a set of policies and proce- dures that governs who is eligible to seek assistive technol- ogy intervention and what devices and services they cover. Langton and Hughes (1992) describe a framework called “tech points” for inclusion of assistive technology in the vocational rehabilitation case management process. They identify key points during the consumer’s vocational reha- bilitation at which technology should be considered. This approach is valuable because it includes a mechanism through which the vocational case manager can monitor whether a criterion for assistive technology services exists for individuals in his or her caseload. Depending on the policies of the ATP, referrals are accepted from a variety of sources. These sources include the consumer, a family member or care provider, a rehabilitation or educational professional, or a physician. At this time, information regarding the consumer’s background and perceived assis- tive technology needs is gathered for the initial database. This information includes personal data (e.g., age, place of residence), medical diagnosis and health information, and educational or vocational background. Information related to the individual’s medical diagnosis and health informa- tion that may guide the assessment includes whether the condition is expected to remain stable, improve, or decline. The appropriateness of the referral is viewed from the per- spective of both the ATP and the referral or funding source. When exchanging information about the con- sumer’s needs and the services provided by the ATP, each party can determine whether there is a match. One out- come is that the needs of the consumer do not match the services provided by the ATP. For the consumer’s benefit, this mismatch should be acknowledged and the consumer referred to another source that can more appropriately address his or her needs. The assistive technology provider should have, within the organiza- tion’s mission statement, a policy that establishes what services are provided and who is eligible to receive services. For example, some assistive technology service providers specialize in certain disabilities (e.g., visual impairment), and others focus on specific technologies (e.g., seating technologies). Professional codes of ethics and standards of practice (see Chapter 1) require that ATPs practice

within their specialization and not try to provide services outside of this realm.

The other outcome is that there is a match between the needs of the consumer and the services provided by the ATP. In this case, funding is sought and plans are made to move forward with the initial evaluation, starting with a thorough identification of the consumer’s needs. From the informa- tion provided, the ATP also determines the level of service that would be most beneficial to the consumer. There are a number of scenarios. First is the individual who has never used or been evaluated for assistive technologies, which could be an individual who is newly disabled or someone with a long-standing disability. An individual with a long- standing disability who may not have previously been a can- didate for assistive technology services may now be able to access assistive devices because of recent advances in tech- nologies. In this situation an in-depth assessment is war- ranted. Referrals may also be received from consumers who have used technology for some time and would like to eval- uate current commercially available technologies. If this per- son’s functional status has remained stable, it may not be necessary to conduct a complete evaluation. In some cases the assistive technology is not working or has been aban- doned by the consumer and he is seeking a referral to see if modifications to the system can aid in making it more func- tional. Sometimes the consumer may only require further training or re-evaluation of how he or she is using the cur- rent system to see whether training in new strategies would be beneficial. Similarly, there may be a new care provider who needs training or technical assistance.

Initial Evaluation

Through a systematic evaluation, the ATP gathers informa- tion and facilitates decisions related to eventual device use. Because of the cost of the assistive technology to the con- sumer (or third-party funding source), it is essential that the ATP be able to assist the consumer in making informed decisions in the selection of a device. Current knowledge of the available technology and use of a systematic process facilitate the ATP’s ability to make such decisions. This sec- tion focuses on the type of information gathered and the procedures used during the evaluation. Examples of assess- ment forms that capture most of the data discussed here are included in Appendices 4-1A and 4-1B.

Needs Identification

Through the needs identification process, the individ- ual’s needs and goals, which provide the basis for the assis- tive technology intervention, are determined. Identifying the needs of the consumer is the most critical component of the service delivery process and it is completed at the onset of evaluation. The information collected during needs

P A R T II Service Delivery in Assistive Technologies 99

identification is the cornerstone for measuring the effective- ness of the final outcome. Therefore, it is important to take this step seriously and ensure that there is a consensus among those involved as to the nature and scope of the problem to be addressed by the assistive technology intervention and the goals identified to target these problem areas.

Information gathered during needs identification is also used by the ATP to justify purchase of services and equip- ment. Third-party payers who fund services and equipment want to know what the problem or need is and how the equipment is going to address the need. Finally, the needs identification process results in the development of a plan for completing the remainder of the evaluation, which includes composition of the evaluation team, determination of needed evaluation tools and devices, and identification of further information required (either through evaluation of the con- sumer or by request from outside sources).

Figure 4-3 provides a model for gathering and analyzing information regarding the person’s life roles, performance areas, related activities, and tasks. The consumer’s life role at the time influences his or her needs and goals. Is the indi- vidual a child or an adult? What are his or her life roles? Life roles include student, parent, employee, volunteer, and so on. It is important to note that, as the individual’s life roles change over time, so may the technology that is needed.

Changing life roles, and therefore technology needs, is one of the reasons that consumers may return after a time to be re-evaluated.

In relation to the consumer’s life roles, there are perform- ance areas (self-care, work, school, play, leisure) in which activities are accomplished. Identifying these performance areas helps the ATP to define the activities for which the consumer needs assistance. For example, play (performance area) is very important for a young child (life role), and a child with a disability may be precluded from manipulating toys (activity). Identifying the context in which the consumer will perform these activities is also critical. In Figure 4-3 we show needs identification for a student who is attending college. A major activity for this student is reading the mate- rial assigned from the textbook. The major part of this activ- ity will take place at home for him, but he will also need to do some reading at school.

A task analysis of the skills required to complete the activity is conducted. The consumer and others identify to the best of their ability which tasks the consumer can likely perform himself or herself and which tasks may need to be assisted with technology. This information may be unknown in some cases, and the evaluation can determine which tasks the individual needs assistance with. In our example the activity of reading is broken down further into small tasks.

100 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

Life Roles/ Performance

Areas Activities ContextsDifficult Tasksto Perform

Prior Technology

History

Intervention Goals: Directions:

1. College student education

1. Evaluate alternatives for holding reading material and turning pages in order to increase Joe’s independence in reading.

1. Reading class assignments in textbook

1a. Holding the book

1b. Turning the pages

1a. Home 1b. Library

1. Has used mouthstick and bookholders in the past; encountered problems positioning book and mouth becoming tired from holding mouthstick

1. Identify consumer’s life roles and performance areas. 2. Identify activities consumer is interested in performing. 3. Identify the specific tasks the individual has difficulty performing. 4. Identify the contexts in which these activities are carried out. 5. Determine if consumer has used technology in the past for the activity and what the outcomes were.

Figure 4-3 Identifying consumer needs with the HAAT model.

If the student has a physical inability to hold the book and turn the pages, resulting in the need for manipulation of reading material, we identify this inability as a need in the third column. Another student who may have difficulty with the activity of reading because of a visual impairment will require different technologies to meet this need.

The consumer’s prior history with technology should also be discussed as part of the needs identification. Useful information can be gathered from the consumer’s previous success or failure with using assistive technology. Has he or she had experience in using technology before, and if so, what technology was used and was the experience success- ful? If not, why? In our example the student had attempted to turn the pages of different books with the use of a mouthstick, which turned out to be unsuccessful. It is important to identify and discuss reasons why the mouth- stick did not work for the individual. Perhaps the mouth- stick was cumbersome and uncomfortable to use for any extended period, or perhaps the individual could physically perform the task with the mouthstick but did not like the esthetics of it.

Beukelman and Mirenda (1998) discuss the need to identify actual or potential “opportunity barriers” and “access barriers” for the consumer. Although their model specifically targets consumers with augmentative communication needs, it also holds true for other areas of assistive technology. Opportunity barriers are imposed by individuals or situations that are not under the consumer’s control. Generally the provision of assistive technology does not result in the elim- ination of these barriers. Beukelman and Mirenda (1998) identify five types of opportunity barriers: policy barriers, practice barriers, attitude barriers, knowledge barriers, and skill barriers. Policy barriers are legislative, regulative, or agency policies that govern situations in which consumers find themselves. For example, there are regulations in some school districts that restrict the use of school-purchased assistive technology to use in the school, preventing it from being taken home. Practice barriers refer to routine activities that are not dictated by policy but that constrain the use of assistive technologies. If the school’s policy does not require that the device stay in the school, but the local teacher or principal has the practice of keeping the devices in the school, the result is the same as if it were a policy. Attitude, knowledge, and skill barriers all apply to those individuals with whom the consumer interacts and on whom the effec- tive use of the device depends. If the consumer’s job super- visor has a negative attitude regarding the use of automatic speech recognition because it is distracting to other workers, it is an attitude barrier that prevents the consumer’s partici- pation in that job. Alternatively, the supervisor may have insufficient knowledge or skill regarding automatic speech recognition to ensure that it is effectively installed and made available to the consumer. The approach taken by the ATP to overcome opportunity barriers is very different depending

on the type of barrier. It may involve training (for skills or knowledge), lobbying (for policy, attitude, or practice barri- ers), or a combination of the two.

Access barriers are barriers related to the abilities, atti- tudes, and resource limitations of the consumer or his or her support system (Beukelmen and Mirenda, 1998). During the needs assessment before an augmentative communica- tion evaluation, for example, all the consumer’s current ways of communicating can be identified. Known constraints related to user and family preferences and the attitudes of communication partners are other access barriers that should be identified. A potential barrier to accessing tech- nology, one commonly seen during augmentative communi- cation assessments, is resistance on the part of parents to pursue an augmentative communication device because they are worried that the use of such a device will inhibit the child’s development of natural speech. As discussed later in this chapter, the ability to find funding for assistive technol- ogy systems and services may also pose a barrier. Identifying potential and actual barriers (both opportunity and access) during needs assessment will help the ATP formulate strate- gies for assessment and intervention.

The information for the needs assessment can be derived from an interview or through a written questionnaire completed by the consumer or his representative. In Appendix 4-1A we provide one example of a questionnaire. Instruments such as the Matching Person and Technology Assessments (Scherer, 1998) can also be used by the ATP to identify the areas of the individual’s needs and his or her predisposition to use assistive technology. If the information is gathered through a written questionnaire before the ATP actually meets the consumer, it should be reviewed at the time of the first meeting with the consumer. The purpose of reviewing this material at the first meeting is to ensure that all the neces- sary information has been provided and to analyze the infor- mation to develop the goals. The total team should also be present at this meeting, and everyone’s input regarding the needs and goals of the consumer can be discussed and a con- sensus reached.

Skills Evaluation: Sensory

As discussed in Chapter 3, auditory, tactile, and visual senses all play a role in the use of assistive technology. In recom- mending assistive technologies, the ATP needs to be aware of the consumer’s sensory abilities and limitations. The ATP is not expected to diagnose sensory impairments such as hearing loss or visual impairments. Consumers who have sensory impairments have usually undergone evaluation by a specialist (e.g., audiologist, ophthalmologist, or optometrist) and are able to provide the ATP with a report that details the degree of impairment. If this testing has not occurred, the ATP should make a referral to an appropriate source before proceeding.

P A R T II Service Delivery in Assistive Technologies 101

The ATP needs to be able to identify sensory functions that are available. If the primary disability is sensory, an alternative sensory pathway may need to be used, so the ATP needs to know what the consumer’s sensory capabili- ties are. For example, in the case of a consumer who is blind and who needs to read, the ATP must evaluate tactile and auditory skills that can substitute for vision during reading (see Chapter 8). In other cases a consumer may have a sen- sory disability resulting from either a physical or a cognitive limitation. For example, if a consumer is hard of hearing, the ATP needs to know how this will affect interaction with technology. This includes everything from hearing warning beeps when a computer error is made to understanding voice synthesis on a communication device.

Evaluation of Functional Vision. The most critical visual skills needed for assistive technology use are sufficient acuity to see the symbols used in the system of choice or to iden- tify small objects in the environment; adequate visual field to allow input of information from a display (e.g., the keyboard or the monitor) or the environment; and sufficient visual tracking ability (e.g., for reading or tracking a moving cursor). During the initial interview, known visual problems should have been iden- tified, but a visual screening may also identify previously unde- tected deficits. The ATP can evaluate the effect of these deficits related to the use of technologies.

Identifying any visual field deficits a consumer may have is extremely important in the application of assistive technol- ogy. Visual field is commonly assessed by having the con- sumer look straight ahead and then indicate when he or she first sees a moving stimulus appear in the peripheral visual field. The stimulus is held approximately 18 inches away and moved in an arc toward the consumer’s midline. This testing is typically done for the right and left peripheral fields and the upper and lower fields. Peripheral field vision is consid- ered intact if the stimulus is seen when it is parallel to the person’s cheek and impaired if the individual does not indi- cate that he or she sees the object as it approaches the cen- ter of his or her face (Dunn, 1991).

In some cases it is difficult to identify the effects of visual field limitations on assistive technology use. For example, individuals with a visual field deficit may make errors in typ- ing because they do not see the whole keyboard. If the ATP is not careful, this performance may be interpreted as a physical limitation instead of a visual field deficit. If motor limitations were assumed, the keys may have been made larger so that the consumer could hit them more easily, an expensive and unnecessary step.

Visual tracking is the ability to follow a moving object. This skill is necessary for many assistive technology tasks, such as following a moving cursor on a screen, following the rotation of a plate with food in a feeder, or following objects in the environment while driving a wheelchair. Visual tracking is usually tested by having the consumer follow a moving

object with the eyes. The object is held approximately 18 inches in front of the consumer and moved horizontally, vertically, and diagonally. The ATP notes whether the two eyes track together, whether the eye pursuits are smooth or jerky, whether there is a delay in the tracking, and whether the eyes can track without head movement.

Limitations in visual tracking ability may significantly reduce the options for specifying and designing an assistive technology system. In particular, these results have implica- tions for the use of scanning augmentative communication systems in which the cursor moves left, right, up, and down (four-way directional scanning). It may be that an individual with a disability is able to track more easily to the right and down than to the left and up. In this case, two-way direc- tional scanning, right and down, is preferable to using all four directions. When the cursor gets to the extreme right of the display, it automatically wraps around and begins from the left side again. Similarly, when it gets to the bottom, it wraps around to the top.

Visual scanning differs from visual tracking in that the object does not move; instead the eyes are moved to view different parts of a scene to find a desired object or location. This skill is used, for example, to locate obstacles during mobility and to scan a keyboard to find a specific key. The eye movements used in visual scanning are the same as those used in tracking. We often assess this capability by presenting arrays of pictures, symbols, words, or letters and asking the consumer to choose one item from the array. In Chapter 3 we described visual accommodation as the ability of the eyes to adjust to objects near and far. This component is impaired in many persons with disabilities, and it is important to be aware of possible accommodative insufficiency during the assessment process. A visual accommodation impairment may be observed by changing the visual focus between a monitor and keyboard. If the monitor and keyboard are far apart, the person may have more difficulty than if these objects are visually close. An individual’s ability to see objects (visual acuity) is affected by (1) the size of the object, (2) the contrast between the object and the background, and (3) the spacing between the object and surrounding back- ground objects. These three considerations apply to symbols as well as to objects. For testing of visual acuity, actual objects, photographs, line drawings, orthographic symbols, letters, and words are used. It is helpful to have a set of materials that includes objects of 3 to 4 inches high; large letters, pictures, and symbols 1 to 2 inches high; and letters and words down to the size of standard typewritten letters (an eighth of an inch) (Cook, 1988). Information gathered from the initial interview can guide the ATP as to the type and size of symbol to start with. The goal is to find the smallest size of symbol that can be seen well by the con- sumer and that results in accurate selections, which are tested by presenting two items of the selected size and sym- bol type at a time to the consumer. The individual is asked

102 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

to identify one of the two items using the manner in which he or she usually indicates a choice (e.g., eye gaze, pointing, yes/no). Three trials of each size and symbol are completed before proceeding to the next smaller size, until the individ- ual is no longer able to identify the item successfully. It is desirable for the consumer to be able to see a small size for a number of reasons. First, the smaller the size, the larger a given array of symbols can be. Second, this allows greater options in hardware and software, including standard key- boards and software that have been developed for the nondisabled population.

If the consumer is able to read but appears to have difficulty seeing words, the effects of various foreground-background combinations (to improve contrast) and letter spacing can be assessed by using computer displays and software designed for this purpose (see Chapter 7). For example, most word process- ing software allows alteration in the background and fore- ground (letters) colors. Special software designed for persons with visual impairments also adds size variation to these capa- bilities. For computer applications, these features can improve performance.

We can improve visual performance by using enlarged graphics or text and by designing control panels with dark backgrounds and light lettering or controls. Identifying switches or keys with colors more distinguishable to the individual may be helpful. Switches can be light colored and placed on a dark background to improve recognition, and language board arrays can have bold dark letters or pictures on a white background, or vice versa. Likewise, video screens and the input array need to be carefully planned so that the amount of information presented is not cluttered.

Evaluation of Visual Perception. As discussed in Chapter 3, visual perception is the process of giving mean- ing to visual information. Visual perceptual skills that need to be considered during assessment include depth percep- tion, spatial relationships, form recognition or constancy, and figure-ground discrimination. Visual perception is an important consideration when considering the client’s abil- ity to interpret information presented in a visual display or to safely navigate a mobility device in the environment. Formal testing of the consumer’s visual perception may have been completed before the assistive technology assessment, and results of this evaluation can be gathered during the ini- tial interview. It is necessary to observe the consumer during functional tasks and note any apparent perceptual problems. If there is still some concern regarding the exact nature of the problems, a formal evaluation such as the Motor Free Visual Perception Test (Colarusso and Hammill, 1972) can be used.

Evaluation of Tactile Function. There are three par- ticular circumstances in which attention needs to be paid to the evaluation of tactile sensation. These occur during

seating and positioning assessments, when evaluating tactile input for the use of control interfaces, and when considering the use of tactile alternatives to vision or hearing.

Somatosensory input is necessary for detecting forces or pressures exerted on the surface of the skin. Individuals who lack sensation may sit for prolonged periods without shift- ing position, which can result in skin breakdown. The ATP needs to be aware of an individual’s sensory status in these situations and be able to evaluate pressure on the sitting sur- face. Dunn (1991) presents a specific testing protocol for tactile response. Additionally, observation and monitoring of the skin surface is necessary. Tactile functions that are included in a somatosensory protocol include one-two point discrimination, perception of light touch versus deep pres- sure, perception of temperature, joint position sense, and localization of tactile stimulation. Somatosensory function is responsible for providing information regarding the location of a control interface, the movements required to activate it, and whether it is successfully activated. Lack of ability to receive appropriate sensory input (e.g., because of Hansen’s disease, nerve injuries, or sensory loss from aging) can severely limit the effective use of control interfaces. The ini- tial interview generally reveals whether somatosensory deficits are present. During functional tasks, the ATP’s skilled observation can identify limitations caused by sen- sory deficits. Dunn’s (1991) sensory testing protocol can also be applied in this situation. In the case of decreased tactile sensation, the control interface needs to provide adequate feedback so that it compensates for the loss of sensory func- tion (see Chapter 7). When visual or auditory function is inadequate for the input of information, we often use tactile substitutes (see Chapters 8 and 9). To determine whether this alternative sensory input is viable for an individual, tac- tile function must be evaluated. In particular, the skin response on one or more fingers is evaluated by using two- point discrimination and similar tests. This evaluation is necessary because certain diseases (e.g., diabetes) that result in loss of vision also cause reduced tactile sensation.

Evaluation of Auditory Function. The ATP, through the initial interview and observation during functional tasks, should be aware of any significant auditory impairments that may affect device use. In cases of suspected hearing loss, a formal evaluation by an audiologist should be requested. Basic information sought by the ATP should include whether the individual responds to auditory stimuli, is dis- tracted by some or all sounds, recognizes specific auditory stimuli (e.g., someone calling his or her name), and responds appropriately to auditory stimuli (Dunn, 1991). For example, many augmentative communication devices emit a beep when a selection is made. For some individuals, this cueing is helpful; however, for others the beep may produce a startle reflex that interferes with the succeeding motor movement. The individual may eventually habituate to the beep, but it is

P A R T II Service Delivery in Assistive Technologies 103

important to consider a device that has the option of dis- abling it.

Skills Evaluation: Physical

The overall goal of the physical skills evaluation is to deter- mine the most functional position for the individual and evaluate his or her ability to access a device physically. At a very basic level, physical skills include range of motion, mus- cle strength, muscle tone and the presence of obligatory movements. Many protocols exist for evaluation of range of motion. Both passive and active ranges of motion are assessed. Range of motion is important in consideration of position- ing needs for function and the amount of movement avail- able to access a device or perform a task. Related to range of motion is muscle strength. Again, many protocols are avail- able for testing muscle strength. Muscle strength is graded in a range from unable to move independently, moves with gravity eliminated, able to move against gravity, and moves against different degrees of resistance. It is important to note that the presence of a neurological disorder such as cerebral palsy, stroke, or traumatic brain injury will affect both range of motion and muscle strength. Typical protocols for testing these components are not generally useful for these popula- tions because the position of the individual affects muscle tone and subsequently range of motion and muscle strength. For example, a child with cerebral palsy may seem to have limited flexion range of motion in the lower extremities when lying in supine. However, when turned on the side, the ability to flex the legs is much easier. In supine, the influence of the tonic labyrinthine reflex increases extensor tone. This influ- ence is not present in side lying, making flexion much easier.

Muscle tone and the presence of obligatory movements are important considerations for individuals with neurolog- ical disorders. As described above, the position of the indi- vidual affects the available movement. Muscle tone is assessed in various functional positions, particularly prone, supine, sitting, and standing. Obligatory movements, or reflexes, are assessed to determine how they might affect function. Key reflexes or obligatory movements include the asymmetrical and symmetrical tonic neck reflexes, tonic labyrinthine, extensor thrust, bite, and grasp reflexes. The ability to right the head when moved out of a vertical align- ment, either lateral or in the anterior-posterior plane is another component. Postural control is a related component that refers to the ability to maintain the trunk in a vertical alignment. When completing an assessment to determine function in various positions, it is important to handle the client and to challenge his or her balance and postural con- trol to determine the degree of support he or she will need to work in a given position and the movement available in that position.

Sitting and standing balance are additional considerations. The ability to maintain balance in these positions is determined

through observation of the ability to maintain the position independently and the response to challenges to balance in these positions. Sitting balance is described as hands free, where the individual can maintain balance and function without using hands to support himself or herself; hands dependent, where he or she needs to support himself or her- self with one or both hands to maintain sitting; and propped or dependent sitting, where he or she cannot sit without external support. Sitting balance is an important component of a seating and mobility assessment (Chapters 6 and 12).

Gross and fine motor assessments generally test higher- level motor skills. Gross motor skills include balance on one foot, performing symmetrical and asymmetrical movements of the upper and lower extremities, coordinating one side of the body, lifting and carrying objects, rapidly alternating movements, and running, skipping, and hopping. Fine motor assessment includes rapidly alternating finger move- ments, performance of isolated finger movements, manipu- lation of objects of different sizes, and performance of specific fine motor tasks. The Bruinicks-Oseretsky Test of Motor Proficiency (Bruininks, 1978) and the Movement ABC (Henderson and Sugden, 1992) are two examples of comprehensive motor evaluations appropriate for children. The Gross Motor Function Test (Russell et al, 2002) is designed specifically for children with neurological impair- ments. Once again, if a neurological condition is present, it is important to remember that function is dependent on the client’s position.

Identifying Potential Anatomical Sites for Control. In Chapter 3 we identify the control sites that can poten- tially be used by the consumer to operate a device (see Figure 3-10) and describe the various movements that each control site is capable of performing.

When individuals with physical disabilities are evaluated, it helps to keep in mind the movement capabilities of each of these anatomical sites and the hierarchy in which these sites are considered. The hands and the fingers are the pre- ferred control sites because they are naturally used during manipulation tasks and finer resolution can be achieved. If the hands are not an option for control, the head and mouth are considered next. With the use of mouthsticks, head pointers, or light beams, it is possible to achieve the fine resolution and range needed to control a device. The next option to consider is the foot. Some individuals are able to develop fine control of the foot for typing (Figure 4-4); however, problems with positioning the device so that the user can see it make this site less desirable than the hands or the head. The least desirable sites are the legs or the arms because they are controlled by larger muscle groups, so the movements of these sites are gross in nature compared with the fine movements of smaller muscles (Cook, 1988).

Simulation of functional tasks is used to evaluate the types and quality of movement an individual possesses.

104 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

Functional tasks are chosen for evaluation because they are often more meaningful to the consumer than physical per- formance components such as strength and joint range of motion. They also provide the ATP with an opportunity to gather qualitative information regarding the consumer’s movements, and results of such tasks are more likely to reflect the consumer’s true abilities.

We present a model based on clinical experience to deter- mine the best anatomical site for accessing a control inter- face. The hands, being the control site of choice, are the first to be assessed. Basic hand function can be observed and rated by using a “grasp module” (Figure 4-5), which includes

a total of seven functional grasp patterns. The consumer’s ability to complete each grasp pattern is rated (unable, poor, fair, or good). Notations are also made regarding how the consumer completed the movement and the factors that made it successful or not. For example, did the object need to be positioned in a particular way for the consumer to grasp it? Was there a delay in initiating the movement? Did the consumer have difficulty releasing the object? Was the movement pattern isolated or synergistic in nature? Did the consumer appear to have problems with depth perception when reaching for the object?

If the consumer has the potential for hand use, it is then necessary to determine the minimal and maximal arm range within a workspace and the resolution in hitting a target. A range and resolution board, as shown in Figure 4-6, can be used to measure both of these. If possible, the consumer is asked to use the thumb or a finger to point to each corner of each numbered square. If the consumer is unable to point to the corners, he or she is asked to touch each square with the whole hand. This provides information regarding the approximate size of the workspace and the best locations for a control interface and a rough measure of accuracy of movement. Both arms are evaluated as appropriate.

If the hands are eliminated as a control site, other anatomical sites must be considered. For example, we can also measure range and resolution for the foot and head. With a range and resolution board of smaller dimensions, the same task can be used to evaluate foot range and target- ing skills and the consumer’s range and resolution with a mouthstick, light pointer, or head pointer. Appendix 4-1B shows a sample assessment form for documenting the infor- mation gathered during the physical skills evaluation. After completion of this component of the skills evaluation, the ATP

P A R T II Service Delivery in Assistive Technologies 105

Figure 4-4 Child using her foot to control an expanded keyboard.

Palmar Spherical grasp Lateral

Hook or snap

Tip Cylindrical grasp

Figure 4-5 Functional grasp patterns for evaluating hand use.

should have a good idea of the user’s physical skills and the anatomical sites that can best be used to control an interface.

Selecting Candidate Control Interfaces. Once the ATP has identified anatomical sites that the consumer can potentially use, the next step in the process is to select con- trol interfaces that have potential to be used successfully by the consumer. In Chapter 7 we present a set of control interface characteristics that are useful in selecting inter- faces that most closely match the consumer’s available anatomical sites.

Comparative Testing of Candidate Control Interfaces. Once potential anatomical sites and candidate control inter- faces have been chosen, next the consumer’s ability to use these interfaces is measured. Comparative testing provides the ATP with data on the consumer’s speed and accuracy in using particular control interfaces. These data can be used to compare different interfaces operated with a given site. If a control enhancer (e.g., mouthstick, head pointer) or modifi- cation (e.g., keyguard) is being considered, its use should also be evaluated (Chapter 7). This is one area where gathering

quantitative information on the person’s ability to use the control interface is extremely valuable and can assist the ATP in making decisions regarding the selection of a control site and interface. It is also important to note the consumer’s preferences during this process.

During the assessment process, speed of response is often used to compare control interfaces. Speed of response is a tem- poral (time-based) measurement that can be quantified. Because these measurements are typically made in the con- trolled setting of the clinic, they must be carefully applied to contexts outside the clinic. Another measure used to com- pare control interfaces is accuracy of response. This is often based on moving to the correct position, and it is therefore a spatial measurement, rather than a temporal (time-based) measure. Measurement of accuracy requires a standard of performance. This is usually the number of correct responses out of the total number of trials. Speed of response and accuracy are generally inversely proportional to each other for novice users.

When these two basic parameters are defined, methods for measuring them can be described. The selected control interface is first placed in a position where the consumer can

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activate it. It may be necessary to try different locations for the control interface before finding the position at which the consumer has the greatest control. The consumer’s time to move from a rest position to target the control interface can be measured with a stopwatch.

Computer-assisted assessment provides several useful features. First, data collection and analysis can be auto- mated, relieving the clinician of tedious record keeping. Performance measures for each possible control site/inter- face pair can be obtained. The effects of different positions for the control interface or the use of control enhancers and modifications can also be measured. Because several differ- ent control site/interface combinations can be evaluated, this data collection process can facilitate the choice of interfaces on the basis of measured results. Second, the computer can provide a variety of contingent results (including graphics, sound, and speech) when the control interface is activated. This variety of results not only makes the task more inter- esting, but it also can allow assessment of visual and auditory capabilities.

Skills Evaluation: Cognitive

Chapter 3 describes the major cognitive skills associated with assistive technology use. Although there are standard- ized test batteries that are used for cognitive assessment (Duchek, 1991), in general we do not use them for evaluat- ing consumer’s cognitive skills related to assistive technolo- gies. Instead, clinical observation is the major strategy used for the collection of information regarding a consumer’s cognitive function. Clinical observation yields information that is often not provided by standard tests. For example, by observing a consumer using a switch-activated program on the computer, the ATP can obtain an indication of the con- sumer’s level of attention, understanding of cause and effect, degree of motivation, and ability to follow directions. Assessment of cognitive skills is important when determin- ing whether the client will be able to learn how to use the technology and whether he or she has the capacity to use it effectively in the long term.

All three types of memory discussed in Chapter 3 (sen- sory, short-term, and long-term) are important for the use of assistive technologies. Memory tasks related to assistive technology can be evaluated by structured clinical observa- tions. For example, the ATP can have the consumer memo- rize a group of codes and then note the consumer’s ability to remember these codes during an encoding task.

Problem solving can also be measured during functional tasks. For example, when an electric feeder is used, it is nec- essary to rotate the plate to position the food so that the spoon can pick it up. Proper use of this technology requires a high degree of problem-solving skills. If the person lacks these skills, use of the device becomes frustrating and an alternative should be considered. The value of this type of

cognitive assessment is that it occurs during completion of a functional task, which may be predictive of assistive technology system use.

Skills Evaluation: Language

The evaluation of language skills required for the use of assis- tive technology devices focuses on both expressive and recep- tive abilities. In addition, the ability to sequence items, use symbol systems, combine language elements into complex thoughts, and use codes is important in operating various types of assistive technologies. Although the most extensive language evaluation is carried out for augmentative commu- nication system recommendations (see Chapter 11), lan- guage skills and use are also important in using other assistive devices such as mobility systems (see Chapter 12) or systems for manipulation (see Chapter 14). Also, language and hear- ing are closely coupled, and assistive technologies intended for persons with hearing impairments must address language and auditory skills (see Chapter 9).

Specific areas that are evaluated include categorization, sequencing, matching, social communicative skills (e.g., degree of interaction), receptive language skills (e.g., recognition of words or symbols, understanding of simple commands), motor speech skills, and pragmatic language skills. Advanced language capabilities (e.g., syntax and semantics) are also evaluated when possible. The evaluation of these skills for augmentative communication device use is discussed in Chapter 11.

Matching Electronic Device Characteristics to the User’s Needs and Skills

The assessment process to this point provides the basis by which the ATP and the rest of the assistive technology serv- ice delivery team carefully define the goals to be accom- plished and determine the skills the consumer has available for assistive technology system use. It is necessary to system- atically transform these goals and skills into characteristics of assistive technology devices. In this section those aspects that are specific to the characteristics of electronic devices are considered. The term device characteristics refers to general properties of the technology. A feature is a particular implementation of a characteristic. Characteristics of auto- mobiles include, for example, engine, color, size, perform- ance (acceleration, gas mileage), and doors. Features for these same characteristics might include four-cylinder engine, blue color, compact size, 35 miles per gallon, and two doors. Consumers have certain needs, and they match those needs to general characteristics to select specific features of interest. They also have skills that apply to the selection. For example, a consumer may not be able to use a standard manual transmission and chooses only automatic transmission cars for consideration. Life roles also play a part in the selection decision.

P A R T II Service Delivery in Assistive Technologies 107

For instance, parents with small children may choose a minivan rather than a compact car.

In assistive technology service delivery, a similar match- ing process can be used to choose features that match the consumer’s needs and skills. This systematic approach is superior to using trial and error with all the possible devices that may work and then trying to pick one. To use this approach, however, a set of characteristics to be considered must be defined. A generic set of assistive technology device characteristics is listed in Box 4-2. The categories in this box parallel those used in Figure 2-5 to describe the components of the assistive technology portion of the HAAT model. In the following chapters more specific characteristics are con- sidered for certain areas of assistive technologies: seating systems, control interfaces, computer adaptations, augmen- tative communication systems, mobility devices, manipula- tion devices, and sensory aids.

Human/Technology Interface. The human/ technology interface is the portion of the device with which the consumer directly interacts. The most general human/ technology characteristics, which apply to all devices, are the physical properties. These include the force exerted by the human/technology interface on the person and the force exerted by the person on the interface, the size and weight of the interface, and its texture and hardness. A seating sys- tem may be too hard or soft to be effective, and this feature

can be related to the needs of the individual consumer. All human/technology interfaces must be attached either to the person, to a wheelchair, or to a stable work surface. Consideration of this “mountablilty” characteristic can often mean the difference between success and failure of the human/technology interface. For example, if a consumer has very limited range of arm movement, a switch must be posi- tioned within this range.

Just as the human user exerts forces on the human/ technology interface, the human/technology interface provides feedback to the user. This may be as a direct consequence of the interface. For example, a seat cushion exerts a certain force, depending on its materials, design, and construction. In other cases the user feedback is a separate component, such as a flashing light indicator on a television control or a tactile display on a reading device for a person with total visual impairment. Human/technology user feedback sources can be described in terms of the characteristics of magnitude, type, and origin. These characteristics can be matched to the con- sumer’s needs. For example, the magnitude of a visual display is the brightness of the light. The types of human/technology interface feedback are other characteristics and include visual, auditory, and tactile varieties. Each of these can be matched to the corresponding user skill. The origin refers to the source of the feedback, such as that provided by a seat cushion or the voice output provided from the screen reader.

The next three characteristics listed in Box 4-2 apply to human/technology interfaces used with electronic assistive devices (including power mobility). The number of inputs required to operate any device is a characteristic. This char- acteristic is referred to as the size of the input domain (see Chapter 7). There are many types of control interfaces avail- able, with varying numbers of inputs and requiring different physical skills for activation. The most appropriate control interface for any given consumer is largely determined by the physical and interface assessments that are described here and in Chapter 7.

Depending on the size of the input domain related to the consumer’s needs and skills, a selection method can be chosen. In Chapter 7 two basic selection methods are described: direct and indirect. In direct selection, all the choices are presented to the user at one time and the user has the phys- ical ability to choose any one element directly. With indirect selection, there are intermediate steps required for the user to make a selection. If the number of input signals required (on the basis of needs) is greater than the number the con- sumer can control (on the basis of physical skills), then some form of indirect selection must be used. Individual devices may have both these methods or they may be restricted to only one method. Direct selection requires greater physical skill than indirect selection; however, indirect selection requires greater cognitive, visual, perceptual, and possibly auditory abilities. The consumer’s skills must be taken into account when specific device features are chosen.

108 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

BOX 4-2 Assistive Device Characteristics

HUMAN/TECHNOLOGY INTERFACE Physical properties Mountability User feedback Number of inputs Selection methods Selection set

PROCESSOR Commands Control parameters Data or information processing

ACTIVITY OUTPUT Magnitude Precision Flexibility

ENVIRONMENTAL INTERFACE Range Threshold

PHYSICAL CONSTRUCTION Mountability Portability Packaging

Selections are made from a selection set consisting of the choices available to the consumer. Features of this set include size, number of choices, format (e.g., print, tactile), and type of symbol (real objects, pictures, computer icons, line drawings, traditional orthography, or symbols used to represent an idea). The type of symbol system that is most appropriate to a given individual is determined during the language assessment. The question of symbol system type is obviously essential for augmentative communication devices, but it is also important in other applications. For example, in electronic aids to daily living (EADL), the devices to be controlled must be labeled, and often symbols are used rather than words to make the systems available to persons who have difficulty in reading. Speech labels, generated by synthetic speech, are also used in the selection set for individ- uals who have either visual or cognitive limitations. Along with determining the type of symbols used in the selection set, the size of the selection set is also determined. The num- ber of choices required is often dictated by the consumer’s needs and by other factors such as how many will fit on a display given the consumer’s visual acuity. The choice of these features for a consumer is based on his or her skills in several areas, including sensory, cognitive, and language.

The Processor. Recall that the processor is the element of the assistive technology device that relates the human/ technology interface to the other components. Sometimes this is simply a mechanical linkage (e.g., in a reacher), and in such cases there are not many choices in characteristics. However, processors for electronic devices have several char- acteristics that must be carefully matched to the consumer’s needs and skills. The first of these is the basic set of commands that are necessary to operate the device. It is important to ensure that the consumer can use these so that the system will be functional for the consumer. For example, in a powered wheelchair system the basic commands are forward, back- ward, left, and right. In a communication device, some basic commands include printing a document and speaking. In an EADL the commands may include lights on and off, TV channel selection, and telephone dialing. These are essential for operation. The greater the number of commands, the more flexible the system is to the user. For example, an EADL that can control the television with three functions (power, volume, and channel), turn three appliances on and off (lights, drapes, and door lock), dial a telephone (three commands), and access an emergency message machine has 10 functions. The more commands included, the more confusing the sys- tem can become. The consumer, family, care providers, and ATP need to evaluate the effect of a specific command size during the assessment.

A second characteristic of the processor is the control parameters. In contrast to commands, control parameters allow adjustments to be made to the system; they are nice to have but not always essential. Control parameters include

such things as variable speed for forward and reverse or indoor and outdoor speed levels in a powered wheelchair. In an augmentative communication device, control parame- ters adjust the voice synthesizer pitch, voice type, and rate to affect the way the speech output sounds. A control parameter also provides the ability to switch between different applica- tions for multiple activity outputs. For example, it is possible to operate an EADL, communication device, and computer access system from a powered wheelchair controller. Individual control parameters need to be presented to the consumer for the systems being considered, and both the consumer and the ATP need to evaluate their effectiveness.

The final general processor characteristic is data or infor- mation processing. In this case the device is internally pro- cessing information rather than dealing with commands or control signals. One example, used in augmentative commu- nication systems and screen readers for the blind, is the gen- eration of spoken output from text using software programs. By listening to several speech systems, the consumer can determine the intelligibility of each and identify which one is preferred.

Another type of information processing is word predic- tion, in which the software program guesses at the desired word on the basis of the entries the consumer makes. This type of application can also adapt to the user by learning his or her most frequently used words. Encoding involves the use of a symbol (e.g., number, letter, mnemonic, color) to represent a vocabulary item or a command (e.g., TV ON in an EADL). The user selects the code instead of directly selecting the element, which can increase the user’s rate of data entry. Encoding schemes can be cognitively difficult, and the consumer should try them during the assessment. The consumer may indicate a preference of one encoding method over another after having a chance to try several.

Information processing is also used in sensory systems to convert the input from the environmental sensor to a form that can be presented to the user. For example, a hearing aid uses a microphone to detect voices, amplifies them (data processing), and presents the amplified signal to the ear (see Chapter 9). Different hearing aids have different data pro- cessing, and the consumer can evaluate this characteristic.

Environmental Interface. As discussed in Chapters 2, 8, and 9, the environmental interface is that portion of the assistive technology system that is used to take in information from the external world for use in a sensory substitution sys- tem. For example, when the person has a visual limitation, we use a camera, and when a person has an auditory impair- ment, we use a microphone. Characteristics that apply to this element include the range of the input signal (i.e., how big or small the signal can be and still be detected). The smallest signal that can be discerned from background noise is the threshold. As an example of how these character- istics can be applied, consider the two problems of reading

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and mobility for persons with severe visual impairments. For reading, the device needs very little range because only one letter or line of text needs to be viewed at a time. However, for mobility the environmental sensor needs to take in a variety of sizes (e.g., from a dish to a tree). For reading, the threshold is low (a letter in fine print), but for mobility the threshold can be much higher.

Activity Output. The activity output is what the system accomplishes for the consumer (e.g., communication, mobility, manipulation). The first characteristic that describes the activity output is its magnitude. This includes the volume for a speech synthesis system, the force or torque generated by a powered wheelchair, and the brightness of a video screen display. Precision is a measure of how accurately the system performs the functions and how exactly it accom- plishes its task. For example, a reacher may be able to pick up a cup but not a button. If the consumer needs to pick up the button, then this particular reacher has insufficient pre- cision to accomplish the task. If an output can be used in different contexts or can be used to accomplish different goals for the consumer, we would say that it is flexible. Flexibility can be an important factor when the consumer has many tasks to perform. Careful consideration of context must also be included in choosing specific activity output features.

Physical Construction. The final category of charac- teristics is physical construction. No matter how well a sys- tem works in an assessment session, it will not be effective in everyday use unless the person has access to it at all times. This is determined primarily by the mountability of the sys- tem. Special consideration must be given to both the mounting of the system (or placement on a desk) and the attachment of any components to a wheelchair. For example, mounting of a communication system to a wheelchair must be considered during the assessment to ensure that the cho- sen system is compatible with the consumer’s wheelchair.

Portability is a measure of the degree to which the device can be moved from place to place. This characteristic includes a consideration of size, weight, and power source. For electronic devices, portability often requires that the device be battery operated and that it be small and light- weight enough to be carried or attached to a wheelchair. If the person is ambulatory, his or her ability to carry the device needs to be assessed. There are differences in batter- ies (e.g., life may be a few hours or a few days between charges) and size and weight. For mobility devices, the abil- ity to transport the wheelchair in the trunk of a car may need to be considered. Some wheelchairs fold so that they can be transported in a car trunk, whereas others, such as powered wheelchairs, do not typically fold.

Generally consideration of the characteristics of color, shape, and overall design are done last when a recommendation for

assistive technologies is developed for a consumer. We refer to these as packaging characteristics. Consideration of the consumer’s preferences in this area can contribute to moti- vation to use the system and to overall user satisfaction. However, the consumer’s packaging preferences cannot always be integrated into the system (e.g., the wheelchair may not come in bright orange). All these features should be discussed with the consumer and others to ensure that the device selected will meet the consumer’s needs.

Evaluating the Match Between Characteristics and the Consumer’s Skills and Needs. It is our premise that a large part of the assessment up to this point is best completed without the introduction of specific devices. The focus of the assessment remains on the functional results to be achieved by the technology instead of on the secondary features of technology, such as color, size, and design. Once the basic functional characteristics have been determined, differences in the secondary factors of size, weight, color, and overall design become important, and they may be the basis for a final decision. After the assessment phases described earlier, one or more devices that have the potential to meet the consumer’s skills and needs are identified for the consumer to evaluate. There are two primary ways in which the ATP can evaluate specific technologies for use by the consumer: (1) trial using the actual device and (2) simulation of device characteristics.

Ideally the consumer will have the opportunity to try the devices being considered and evaluate their usefulness before a recommendation is made. However, because of the expense, it is not always possible for the ATP to have access to every available device, nor is it a prerequisite for conduct- ing a skilled assessment. It is desirable that the ATP have available a set of devices that represents a broad range of characteristics. A service delivery program can carefully choose equipment to be used for evaluations, making it possible to address the major characteristics of devices during consumer assessment. Sometimes a short trial during a one-time assessment is not adequate and it is necessary to have the consumer use the device for an extended period. In some cases a local manufacturer’s representative might loan a device to the ATP for a consumer trial. Other manufacturers and service delivery programs lease devices for this purpose. If these devices are available, it is helpful to demonstrate the various features to the consumer and have the consumer try them. There may be two or three devices being considered, and, if possible, each device should be tried and evaluated by the consumer. In lieu of having the actual device available, the ATP can simulate device characteristics. Simulation requires that the ATP be knowledgeable about the character- istics and features available for specific assistive technologies. For computer-based products, the assistive technology adaptations are often software based, and demonstration disks can be obtained from manufacturers or downloaded

110 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

from a manufacturer’s Web site. These demonstration pro- grams illustrate the essential features of the software, but they are not fully functional and their use is time limited.

To position a control interface for simulation during assessment, universal mounting systems that can be adjusted and placed in various positions can be used. This step is important to ensure that the control interface is in a func- tional position for the consumer and that it remains stable during the assessment.

Effects of Errors in Assistive Technology Systems. An important operational characteristic of assistive technol- ogy systems is the way in which they deal with errors. Two types of errors are of concern. Random errors are infrequent and are generally chance occurrences. An example of a ran- dom error is the consumer’s inability to understand a voice synthesizer because of high amounts of ambient noise. If the noise is not present, there is no error, and even if there is noise it may not lead to an error in interpretation. It is only the random co-occurrence of the need to use the voice syn- thesizer, the presence of noise, and a listener who does not understand the output that creates the error. Random errors may recur, but they are not consistently present in the sys- tem. We can do very little to avoid this type of error in the assistive technology system design process.

Of greater concern are periodic, or regular, errors, which occur under predictable conditions. These errors may also be infrequent, but they are foreseeable. As an example, many letter-to-speech software programs make mistakes in pro- nunciation when used with voice synthesizers. The mispro- nunciation always occurs whenever the particular word is entered. This type of error can be dealt with in the design process. For our example of mispronunciation, exception tables are typically used so that the utterance sounds correct although the letter-to-speech rule makes an error. There are several effects of errors on assistive technology system per- formance, including loss of information, injury, and embar- rassment. All three of these can occur in the same system, and they may be due to the human, the activity, the context, the assistive technology, or the interaction of all of these components. For example, a power wheelchair will not func- tion if the user does not regularly charge the batteries. The user must somehow cause the action that results in the bat- teries maintaining a charge, and the power wheelchair system must provide accurate information about the degree to which the batteries are charged. Error-free function here relies on the successful integration of the human with the technology. Loss of information is a common effect associated with aug- mentative communication systems (see Chapter 11) and sen- sory aids (see Chapters 8 and 9). Loss of information refers to an interruption in the output of the system, whether it is auditory or visual, as in a voice output communication aid, or physical, as in the power to propel an electrically powered wheelchair. It can occur because the human operator makes

an error in motor, sensory, or cognitive performance or as a result of a device error. Although the net effect on system performance of either of these errors (human or device) may be the same, it is important to distinguish between them to correct the problem.

When the human operator makes the errors, the distinc- tion needs to be made as to whether the cause is lack of capacity (e.g., inability to control excessive tremor resulting in erroneous selections or visual limitations in reading a dis- play) or lack of skill (inadequate experience or practice in using the device). If the problem is the capacity of the user, then modifications must be made in the system (e.g., using a keyguard to prevent erroneous entries or an enlarged dis- play screen to improve visibility). If the problem is one of skill, training may help reduce the number of errors.

Physical injury is a more serious effect of a system error. This type of error can occur in a mobility system (see Chapter 12) if, for example, a braking system fails or a motor fails to turn off. Consideration of this type of error leads us to the concept of “fail-safe” design. This approach attempts to anticipate the types of errors (termed failures when caused by the device) and to ensure that, if they do occur, the prob- ability of injury is minimized. For example, if a power wheelchair controller fails, it should fail in the off state. If it fails in the on state, the user may be injured because the chair cannot be controlled. Similar to loss of information, the capacity or the skill of the user can cause physical injury. A final general effect of assistive technology system errors is embarrassment. This effect is somewhat unique to assistive technologies, and it is a direct result of the role that assistive technology systems play in the daily life of the user who has a disability. Because the tasks being performed cannot be accomplished without the system, its use is continuous throughout the day. Over a long period, system errors lead- ing to embarrassment are inevitable. The embarrassment may be relatively minor, such as a manipulation system dropping a spoonful of food. In other contexts, it may be much more significant. For example, an augmentative com- munication device may fail and produce the wrong utter- ance. If the context is a presentation in an important meeting and the mistaken utterance is an obscenity, the con- sequences are potentially very negative. To place the impor- tance of this type of error in perspective, recall that the device is often perceived by both the user and other people as being a part of the user. Thus, the user is held responsible for an inappropriate utterance just as if he or she had used his or her own voice to produce it.

The errors and their resulting effects may arise from any of the components of the assistive technology system or their interaction. The human error may be related to capac- ity or skill. The device may malfunction, in which case the error is related to the design. The context may cause an error. For example, the pressure relief properties of a wheelchair cushion may be impaired if the cushion is exposed to

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extremely cold environments for a prolonged time and the cushion materials freeze. An example of an error that is caused by the interaction of the components of the HAAT model relates to devices that have many functions, with com- plex commands required for successful activation. In part, the error is caused by the capacity of the user to learn how to operate the device. It is also caused by the design of the device that requires complex actions for successful opera- tion. Some of the concepts related to human factors that were discussed in Chapter 2 are relevant here.

It is clear from this discussion that identification and reduction of errors can occur at several points in the assistive technology process. Initially, incorporating a design and accompanying soft technologies that are congruent with universal design principles can minimize errors. Errors can be identified and possibly corrected through use of a thor- ough evaluation that leads to a suitable device recommenda- tion, coupled with a trial period. Finally, errors in the assistive technology system are identified and reduced through follow-up with individual users and after market research into the effectiveness of the system.

Decision Making. To propose a set of candidate assistive technology devices for a consumer, it is necessary to choose characteristics of these systems that will meet the needs and be consistent with the skills possessed by the consumer. The most important principle in this process is the relationship between the tasks the assistive technology device must accomplish for a person (embodied in the consumer’s goals) and the characteristics that must be contained in the device for those tasks to be accomplished. Each goal may be accom- plished only if a set of essential characteristics is included in the assistive technology system. For example, the goal may be mobility, and the characteristics of the type of cushion, wheelchair type, and color all contribute to the accomplish- ment of this goal.

Many characteristic-goal relationships are subtler, how- ever, and generic characteristics of devices are not always equivalent to specific features of commercially available assistive technologies. For example, a generic characteristic of all EADLs is turning lights on and off. However, differ- ent manufacturers of EADLs may accomplish this func- tion in different ways. Developing recommendations and a plan for implementation should be based on the consider- ation of device characteristics that have been evaluated by the consumer.

Computer-based expert systems that assist in the decision-making process for assistive technologies are being developed. Depending on the expert system, collection and interpretation of data are incorporated. Expert systems use artificial intelligence to guide the ATP through the assess- ment and decision-making process. Expert systems attempt to mimic the skills of an ATP by using software programs that are capable of making decisions much like humans do.

In assistive technologies, several preliminary systems have been developed. Garrett et al (1990) have developed an expert system called VOCAselect for use in selecting aug- mentative communication systems for specific consumers. Their system is based on 17 features that are determined dur- ing the assessment process. In addition to features related to consumer performance (e.g., input method, vocabulary size), they include physical construction (e.g., portability) and information regarding available support services (e.g., accept- able price range, training availability). These factors are then related to specific features of each available communication device. The expert system matches the specific requirements of the user, on the basis of goals and needs and on assessment of skills, to appropriate devices. By including the weight of factors (e.g., characteristic A is twice as important as charac- teristic B) and a scale of responses (e.g., priority for speech output is nine out of 10), this type of expert system can focus on specific options even more closely. Garrett et al report that preliminary trials indicate exact agreement in device selection between the expert system and a speech-language pathologist.

Stapelton and Garrett (1995) carried out an evaluation of this system. Respondents to a survey indicated strongly (greater than 79%) that this system would be of value in making recommendations for augmentative communication systems. They also present an example of the use of this pro- gram for a specific case. Stapelton et al (1995) extended the VOCAselect concept to the selection of computer adapta- tions (see Chapter 7). This computer program is similar to VOCAselect, but it is built on characteristics of devices and software used to make computers accessible to individuals who cannot use a keyboard or mouse for entry or the stan- dard screen for output. In operation this software is func- tionally identical to VOCAselect. Stapelton et al (1995) present an example of the use of this system.

Regardless of whether an expert system is used, the process we have described is highly effective in defining the features of a recommended system. It is important to recognize that the features that are most limiting must be considered first, followed by those that are less restrictive. For example, in an augmentative communication system, the type of symbol sys- tem is often the most limiting characteristic. If a consumer requires pictures as a symbol, many devices are eliminated immediately. In contrast, spoken output as a characteristic is not as limiting because most devices use similar speech synthesizers. For each type of assistive technology, it is important for the ATP to identify a set of general character- istics that fit within the categories of Box 4-2. These are pre- sented in later chapters. If the characteristics are generic, then specific features can be selected in sequence to define the final assistive technology system. The major advantage of the assessment methods described here is that they are based first on a consideration of the consumer’s goals and skills and second on a consideration of assistive technology

112 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

system characteristics. Thus the system is matched to the consumer (within the limits of current technology) rather than the consumer being forced to adapt to the system. Without a structured approach such as the one presented here, however, it is very difficult to meet consumer’s goals.

It is clear that many characteristics of devices should be considered, and the features (and their costs) will differ from one system to the next. In addition to specific features of the device, other important factors include the contexts of use, the amount of training required before the device can be used effectively, cost, availability of a family member or caregiver to support and facilitate the training and implementation of the device, and ease of use of the device.

Recommendations and Report

The recommendations summarize the information gathered during the evaluation and suggest a design for the assistive technology system. At the conclusion of the assessment, everyone involved should sit down to review it and come to a consensus regarding the final recommendation. A written report is prepared that details the assessment and recom- mendations for an assistive technology system. The written report synthesizes the assessment process, and it starts out by defining the needs and goals that have been addressed. A summary of the consumer’s skills applicable to device use is provided, with a description of generic characteristics to be incorporated into a device. This summary is followed by spe- cific recommendations for equipment, including descriptions, part numbers if applicable, manufacturer’s name, any modifi- cations that need to be made, and cost. Recommendations for soft technologies are also included in the written report. These may include recommendations for developing skills that are necessary before purchase of a device, training once the device has been purchased, and strategies for incorporat- ing the technology into the individual’s context. Finally, a plan for implementation of the recommendations is pro- vided. This includes logistics such as seeking funding from the appropriate sources and who will take responsibility for implementing the recommendations.

Often the written report is aimed at various individuals, thus presenting a unique challenge for the ATP writing it. The report, first of all, needs to be geared toward the con- sumer, who may not be familiar with medical or technical jargon. Rehabilitation or educational professionals working with the consumer may also be receiving the report and its recommendations. These professionals typically need infor- mation on what the consumer’s skills have been in using the technology and what skill areas they may need to address to facilitate the use of the device. Some of these professionals may be very knowledgeable in assistive technology, but for others this may be their first experience with it. The contact person for the funding source will also be reading the report, and his or her interest is typically in the “bottom line,” or

what it is going to cost. This person wants evidence that the system recommended is going to meet the consumer’s needs at the lowest possible cost. In the section on funding in this chapter, we describe how to write a report to a third-party payer to justify the purchase of an assistive technology system.

IMPLEMENTATION

Once the recommendations have been made and funding is obtained, the implementation phase begins. This aspect of the delivery process consists of ordering specified equip- ment, obtaining commercially available equipment or fabri- cating custom equipment, making needed modifications, assembling or setting up equipment, thoroughly checking it as a system, fitting the device to the consumer, and training the consumer and caregivers in its use.

Ordering and Setup

Many recommended interventions have components from several manufacturers, and these must be integrated into a total system. Some of these may be standard commercially available components and others may be commercial assis- tive technologies. These devices are ordered from the man- ufacturer or equipment supplier and may take up to 6 weeks to be received after ordering. The recommendation may have also included a custom device or devices that require an adaptation. Examples of custom modifications include mounting a switch to a wheelchair or table, making a cable for connecting two devices together (e.g., a communication device and an EADL), programming a device for unique vocabulary, and adapting a battery-powered toy so that it can be controlled with one switch. The design and fabrica- tion of these system components can occur during the wait- ing time for the delivery of the commercially available technologies. Once all the individual devices and adapta- tions are available, it is necessary to assemble them into a total package. For example, a wheelchair obtained from one source and a seating system from another will need to be interfaced to each other. The complexity of this assembly process varies widely, and some systems require much more effort than others.

Delivery and Fitting

Once the equipment is obtained, modified, or adapted as necessary and integrated into a system, the system is ready to be delivered to the consumer. This may occur in a clinic setting, in a school or at a job site, or in the consumer’s liv- ing setting. The choice of locations depends on the nature of the equipment, the ease of transport of the consumer, and the complexity of the system (i.e., what support services of technicians and tools are required). We refer to all system

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deliveries as a “fitting” because we are interfacing the human (consumer) with the rest of the system. In some cases, such as custom seating systems, the process resembles a fitting for an orthotic or prosthetic device. In other cases the fitting focuses on installation of the system, mounting the control interface and the device to a wheelchair, and interconnection of the various components. The fitting phase may also include some amount of assessment as adjustments are made to optimize the consumer’s ability to use the system. An example of this is the use of head switches to control a power wheelchair. The head switches must be attached to the wheelchair and wired into the con- troller unit. This is done before the fitting, and during the fitting, the location of the head switches (e.g., how close they are to the consumer’s head) is adjusted to maximize performance.

The complexity of many assistive technology systems may require more than one session to obtain all the proper adjustments, mountings, and fittings. The ATP must be pre- pared to continue making adjustments and adaptations in the system until the consumer’s goals and needs are met. This phase of the delivery process often involves some reassess- ment, but its success is directly related to the quality of the initial assessment and recommendations, and difficulties experienced at this time can often be traced to incomplete or inaccurate assessments.

Facilitating Assistive Technology System Performance

A major concern of everyone involved in the delivery of assistive technology services is whether the device recom- mended is going to meet the stated goals. It cannot be assumed that intervention ends with the delivery of the device. Most users of technology, even those with previous technology experience, require assistance in facilitating their performance with the device. The ATP, as the designer of the system, is responsible for providing the means to facili- tate human performance. The soft technology described in Chapter 1 is relevant here.

Bailey (1989) identifies three methods that facilitate human performance: written instructions, performance aids, and training. He describes the major difference among each of these facilitators as “the time that elapses between when information is presented and when the performance takes place” (Bailey, 1989, p. 325). A performance aid is used immediately and written instructions are read and also used fairly quickly, but information presented during a training session may not be used until months later. In designing performance facilitators for individual users, the ATP should keep this difference in mind. The ATP also needs to know how to provide a balance among these facilitators. For example, many manufacturers of augmentative communica- tion devices develop an abundance of written instructions.

Even if the user were to read all this information, most of it would be forgotten. It has been found that when workers on a job site need information that can be found in similar documents, they either take a guess at the solution or ask someone else (Bailey, 1989). The same thing happens with assistive technology users. An example of this is a person who is hard of hearing and obtains a hearing aid. It may work fine for a relatively long period; then the batteries are discharged and need to be replaced. Often the user merely puts the hearing aid in a drawer because it “doesn’t work anymore” instead of replacing the batteries. If the user does replace the batteries, it is generally because he asked some- one else what to do or was instructed in the process when the aid was sold to him, not because he looked it up in the user’s manual. Bailey admits that there are few guidelines to help the ATP determine when to use performance aids, written instructions, or training but emphasizes that “the best decisions are made when as much as possible is known about the potential users, the activity to be performed, and the context in which the performance will take place” (p. 326). As applicable, each of the following chapters has a section on specific training ideas.

Training. Bailey (1989) defines training as “the acquisi- tion of skills, knowledge, and attitudes that will lead to an acceptable level of human performance on a specific activ- ity in a given context” (p. 387), which is referred to as per- formance-based training. In the field of assistive technology, prior authorization from the funding source to conduct training is usually required. For a funding source to author- ize training, an estimate of the amount of time that will be needed is typically required, with the result that training becomes time based rather than performance based. Time- based training is completed within a specified period, regardless of whether the user achieves a level of skill. Without adequate training, there is an increased likelihood that the device will be abandoned. The training process is facilitated if the ATP starts out by developing a set of well- defined, measurable objectives for training. These objectives help focus the training sessions and serve as an indicator for termination of training. It is also important that there be one person affiliated with the consumer who takes on the role of the facilitator and learns the operation of the device and basic concepts so that he or she can assist with the use of the device as needed.

Training oriented toward establishing operational competence is initiated at the delivery and fitting (Pallin, 1991). This phase of training is intended to make it possible for the user of the technology, his or her care providers and family, and any other support person to begin using the assistive technology system. Examples of considerations included in training for operational compe- tency for the consumer are (1) how to turn an electronic device on and off, (2) making adjustments in operational

114 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

parameters (e.g., adjusting a scanning rate), (3) loading an initial vocabulary in an augmentative communication system, (4) explaining basic maintenance (e.g., battery charging, cleaning), (5) introducing basic functions and how they work (e.g., choosing what to say on a communica- tion device, using an adapted telephone dialer), and (6) basic troubleshooting so that the consumer and others have some strategies to use if problems develop with the sys- tem. It is important to present information in small doses to avoid overwhelming the consumer and others, particularly for a complex system. At the initial fitting session it is only necessary to present enough information so that the con- sumer can begin to use the system. Subsequent training

addresses the acquisition of the necessary skills for more advanced operations.

In addition to basic operational competence, it is necessary for the consumer to develop strategies that maximize the effectiveness of the system. To facilitate this, the ATP provides training for strategic competence. The training focuses on the application of the system rather than on basic operation. As this phase of training progresses, the consumer begins to develop his or her own set of strategies. For example, the per- son using a manual wheelchair will develop strategies for nav- igating curbs or inclines and the user of an augmentative and alternative communication (AAC) device will develop strate- gies for communicating in a noisy restaurant.

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CASE STUDY

TRAINING

Marilyn is a 45-year-old woman who sustained a brain- stem stroke. Her only available control site is very slight movement of her right thumb. She will use this movement to control a computer that provides both verbal and writ- ten augmentative communication (see Chapter 9) and EADL (see Chapter 14). She resides in a skilled nursing facility where she has daily visits from family and church members. One session a week for 4 weeks will be carried out. Her training program will include the following:

Session One Basic operational competence: Instruction in how to connect the switch to the AAC system and to mount the switch for independent access; discussion of setup of software parameters for scanning; presentation of an overview of system features; instruction in charging of batteries and the use of the swing-away mounting systems for the computer and the switches. Basic linguistic competence: Instruction in how to use commands in the word processor to load, save, edit, print, use pictures and use different fonts; instruction in how to retrieve and use vocabulary; and selection of preliminary vocabulary. Basic strategic competence: Discussion of when to use features to maximize effectiveness of the AAC device. Basic social competence: Discussion of how augmented communication differs from speech.

Session Two Intermediate operational competence: Instruction in storage and retrieval of vocabulary in the electronic AAC device. Intermediate linguistic competence: Instruction in how to use advanced features of the word processor and how to add vocabulary to the system.

Intermediate social competence: Discussion of how to be a good communicator.

Session Three Advanced operational competence: Instruction in how to load and use new vocabulary files and how to print. Instruction in how to use the AAC menu to select and con- trol the EADL; demonstration of how to connect devices to remote control receivers and how to make phone calls by using the AAC device. Intermediate strategic competence: Discussion of how to use strategies for conversations with visitors. Development of strategies for conversations with nursing staff.

Session Four Advanced linguistic competence: Practice with word processor for writing. Instruction in how to use special fea- tures to enhance speech output. Advanced strategic competence: Discussion of when to use different system features. Development and use of conversational repair strategies, and effective use of com- menting (see Chapter 11). Advanced social competence: Instruction in how to vary conversational vocabulary and moods for differing cate- gories of interaction and partners, and how to select vocabulary and modes for differing social situations.

Marilyn, her husband, and the staff of the long-term care facility in which she is currently living will devote the period between the sessions to practice. Before the start of each session, information from the prior session will be reviewed to see whether Marilyn has any questions. At the fourth session Marilyn will be evaluated to see how she is doing in using the device and to determine whether she has further training needs.

Performance Aids. A document or device containing information that an individual uses to assist in the comple- tion of an activity is called a performance aid. By decreas- ing the amount of information to be remembered, the performance aid reduces the amount of cognitive processing required to complete an activity. With a performance aid, the user does not have to rely as much on long-term memory, which results in reduced errors, increased speed for certain tasks, and a reduced amount of training required. Performance aids do not necessarily have to be written; picture symbols can also be effective for individuals who cannot read. Bailey (1989) describes five quality standards for performance aids: (1) accessibility, (2) accuracy, (3) clarity, (4) completeness and conciseness, and (5) legibility.

Performance aids are commonly used with individuals who have memory deficits as a result of damage to the brain. One type of performance aid is simple step-by-step instruc- tions that assist the user in carrying out a sequence of tasks. For example, Tim is a young man who has sustained a head injury. He uses a computer to complete school assignments but has problems remembering the sequence of steps to get into his computer word processing program. The steps to do this have been simply written and are posted next to his computer. Because Tim also has visual acuity problems, the instructions are printed in large, bold letters. For Tim, this simple performance aid has meant the difference between success and failure in using his computer.

Another type of performance aid assists in remembering several items of information. An example of this type of aid is a printed list of codes with their meanings, which an indi- vidual may have stored in his or her augmentative commu- nication system. Often such a list such is attached to the side of the device so the user can view it easily as needed. Sometimes codes and their meanings are built into software programs and presented on the screen each time the user selects a letter.

Written Instructions. Written instructions should be considered an integral part of the system and be available to the user at the time of the system delivery. Instructions are helpful when step-by-step directions with detailed informa- tion are required or when graphic information needs to be presented. Written instructions may be compiled and pre- sented in the form of user manuals, handbooks, or computer software. The ATP must not assume that the instructions provided by the manufacturer are going to be adequate. Written instructions provided by the manufacturer of the system may include too little or too much information or they may be difficult to follow by the user. It is recommended that instructions from the manufacturer be reviewed and supplemented as needed. When the manufacturer’s docu- mentation is overwhelming, the ATP can review the docu- mentation and condense it into a quick reference sheet that provides simplified and frequently used information.

Bailey (1989) provides detailed guidelines for developing the various types of written documents, including software documentation. It is important to remember to keep the audience in mind and to write the instructions for the peo- ple who will use them. For example, if the primary person facilitating the performance is the parent, the instructions may be different from those generated if the facilitator is a teacher. In the field of assistive technology, this may mean a new or revised set of instructions for each individual con- sumer, even for use of the same device.

FOLLOW-UP AND FOLLOW-ALONG

Once the system has been implemented, it is tempting to think that the intervention has been completed. This per- ception, however, is totally false; the delivery of the system marks the beginning of the time of use, and it therefore sig- nals the beginning of the evaluation of system effectiveness. The term follow-up refers to activities that occur during the period immediately after delivery of an assistive tech- nology system and that address the effectiveness of the device, training, and user strategies. The term follow- along is used to describe those activities that take place over a longer period. This phase addresses factors such as changes in needs or goals, availability of new devices, and other concerns.

A formal follow-up phase is included in the delivery process for several reasons: (1) assistive devices can seldom be used right out of the box without ever needing to be adjusted, (2) electronic devices are not 100% reliable, and a significant portion of them require repair during the first year of use, (3) training programs seldom proceed flawlessly, and questions arise during the initial period of use, and (4) perceived device failures are often the result of operator error caused by a lack of device understanding. A carefully developed follow-up program will identify these problems easily and address them quickly.

Repair and maintenance are often conducted during the follow-up phase. Repair refers to action taken to correct a problem in a system. Maintenance, on the other hand, is a systematic set of procedures that is aimed at keeping the device in working order. Examples of maintenance functions are proper battery charging, cleaning, tightening mounting hardware, and lubrication of moving mechanical parts. A regular schedule will ensure that necessary maintenance takes place. Assistive technology system failures result in a major disruption of the consumer’s life. For example, a con- sumer depends on a power wheelchair for mobility. If it fails, he or she may have a manual wheelchair as a backup, but the consumer’s independence may be significantly reduced. Repair of assistive technologies is most often carried out either through manufacturer’s representatives or directly through the manufacturer. In the latter case, the device must

116 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

be returned to the factory for repair, and the consumer may be without it for several days or even longer. Prompt atten- tion to repair needs of consumers is an important part of follow-up.

As part of a formal follow-up program, contacts with the consumer (by telephone, on the job site, in the home, or in the clinic) are scheduled on a regular basis, such as at 1, 3, 6, and 12 months after delivery. These contacts occur regard- less of whether there is a perceived problem, and they are in addition to other activities such as training or repair. This regularly scheduled contact is important because there may be unnoticed problems, or more often there are underused features that are discovered during the follow-up sessions. Mortola, Kohn, and LeBlanc (1992) found in a follow-up study that, because of mechanical reasons, 63% of 196 assis- tive devices delivered by their center were not being. In most of these cases the consumer had not informed the ATP of the device failure.

As we have defined it, follow-along has a much longer time frame than follow-up does. Although follow-up typi- cally covers the first year of operation of an assistive technol- ogy system, follow-along is carried out over the individual’s lifetime. Consumers may return for service after a period of years for several reasons. They may have found that the device is not working as they would like and is not meeting their functional goals. Another reason is to obtain informa- tion about advances in technology since they obtained the device. In other cases the consumer may have changed in significant ways. This change is often seen in children who have grown significantly and need a revision in their seating system. Change can also be the result of a degenerative con- dition such as amyotrophic lateral sclerosis, and in these cases the device may need to be altered to accommodate decreased physical function. In other cases the change in consumer condition is a result of the development of new skills that make it possible to consider new device features. For example, a consumer who has had a traumatic brain injury may initially receive a communication device that is based on very simple replay of sentences. As he or she recov- ers, the ability to spell effectively may improve and a device with this capability should be considered.

There are other reasons for follow-along. One of the most important of these is a change in the life roles and context of the consumer. For example, Martin, who has severe cerebral palsy and has used an AAC device for several years, decides to move into an apartment on his own. The success of this transition could depend heavily on the availability of assistive technologies. An EADL would allow him to control lights and appliances, answer and dial the telephone, and control the television, DVD, and other entertainment devices. This re-evaluation is dictated not by changes in his condition but by changes in his life roles and the context in which he will be using his technology.

As opposed to follow-up, follow-along is often initiated by the consumer rather than by the ATP. This is because the ATP is not aware of the changing physical, sensory, and cog- nitive conditions in the consumer. On the other hand, the consumer cannot possibly be aware of changes in technol- ogy. For this reason, it is important that the ATP develop a mechanism to maintain contact with consumers to inform them of changes in technology. This mechanism should empower each consumer to take personal responsibility for his or her long-term assistive technology needs. One fre- quently used method for doing this is a regular newsletter that is sent to consumers by the ATP.

Another reason for both follow-up and follow-along is to evaluate the effectiveness of the assistive technology system by measuring outcomes. This evaluation provides a measure of how well the system meets the original needs identified during the assessment. The next section describes the measurement of outcomes.

EVALUATING THE EFFECTIVENESS OF ASSISTIVE TECHNOLOGY SERVICES AND SYSTEMS

Measuring the outcomes of assistive technology services is a primary focus in the industry today and will continue to be in the forefront of assistive technology service delivery. Consumers want measures that reflect their needs for improved function and quality of life. Payers seek efficient provision of services using the fewest possible resources, and providers seek information on how to deliver efficient and effective assistive technology services. To provide evidence of the effectiveness of assistive technology services and sys- tems, well-developed and sound outcome measures are required.

Fuhrer et al (2003) suggest that a comprehensive concep- tual framework will guide the development of useful out- come measures. They describe a model that will help researchers and clinicians identify assumptions, variables, and populations when developing, considering, and imple- menting assistive technology outcome measures. Outcome of device use is considered to be the frequency and duration of device use.

The model considers different time frames when evalua- tion is important: initial procurement of the device and the introductory period leading to short- and long-term out- comes. Three aspects are considered when a device is obtained: (1) the need for the device, (2) the type of device, including its intrinsic and extrinsic properties, and (3) the services involved when obtaining the device (Fuhrer et al, 2003). A number of constructs are considered in evaluating short- and long-term outcomes, including effectiveness, efficiency, satisfaction with the device, psychological func- tion, and subjective opinion of the contribution of the device

P A R T II Service Delivery in Assistive Technologies 117

to the client’s well-being (Fuhrer et al, 2003). If the user is not satisfied with the device, it may be abandoned in either the short or the long term. The constructs related to the International Classification of Functioning, Disability, and Health (ICF) (World Health Organization [WHO], 2001) are mediating factors in the short and long term. This clas- sification is described in Chapter 1.

When outcome measures for assistive technology sys- tems are considered, the ATP needs to develop measures and standards of performance that allow a careful determi- nation of the effectiveness of such systems. For instance, a child who is evaluated for a power wheelchair (see Chapter 12) will have a level of accuracy, speed, and reliability that can be measured. Speed of response and accuracy are both used to assess power wheelchair performance. The speed of response is important in describing how quickly a disabled consumer reacts to obstacles, and accuracy is a measure of how well the consumer can navigate a specific course. If this is used as the baseline performance, progress over time can de determined by comparing performance with this baseline. In a clinic or laboratory setting, these measures can be used to select a control interface (see Chapter 7) and to determine such things as the feasibility of safe powered mobility. However, to determine the success of the desired functional outcome (independent mobility), measures must be made in the intended context. This requirement raises several additional questions, such as what is the standard for accuracy of power wheelchair use in a shopping mall? Is it a minimal number of collisions with people and objects? If so, how many are acceptable? Is it being able to successfully negotiate a crowded store? If so, what is being measured to assess suc- cess (e.g., minimal breakage, no collisions, how fast the user gets to the door)? Obviously, measuring and assessing assis- tive technology system performance in the real world is not an easy task. In the remainder of this chapter the focus is primarily on the measurement of outcomes of the use of assistive technology devices and the provision of services.

Overview

The effectiveness of assistive technology systems in meeting the needs of consumers is related to many factors. Sackett (1980) identifies four types of evaluation to consider: effec- tiveness, efficacy, availability, and efficiency. These can each be related to different questions and to different assessment instruments. For evaluating effectiveness we ask the question, does it work? Effectiveness is measured in terms of the impact of the product on the consumer’s life and needs. Therefore the outcome measurements that we collect must begin with and focus on the consumer and the results of the assistive technology intervention. These outcomes allow us to determine the efficacy of the service delivery structure and process. Efficacy is the ability to produce a desired result or effect; the question to be asked is, can it work? This aspect

is what is measured in evaluation of a service delivery structure and process. It provides useful information on how services are being delivered so that necessary revisions can be made.

The entire assistive technology industry is evaluated by the success of service delivery and assistive technology sys- tem use by the consumer. As described above, the consumer and the delivery of assistive technology services are at the core of the assistive technology industry (see Figure 1-2). Gathering information on outcomes should be included as a regular part of the service delivery process so that this infor- mation can be used as feedback to the rest of the industry. For example, a manufacturer could be determined to have good manufacturing practices and meet all industry stan- dards; however, the most meaningful standard is the effec- tiveness of the equipment for consumers. Likewise, the effectiveness of the equipment is only as good as the service provider who delivers it. If, as a whole, there are problems with consumer use of assistive technology, all the industry will be affected. This aspect is related to evaluation of avail- ability, which asks the question, is it reaching those who need it (Sackett, 1980)?

Finally, the question, is it worth doing? needs to be answered. This addresses the relative importance of the serv- ice being provided by comparing it with other programs that could be purchased with the same resources. This evaluation measure is referred to as efficiency. Third-party payers want to know that the assistive technology services and devices are worth paying for. It is the ATP’s responsibility to provide this justification.

A wide range of outcome data needs to be collected, and determinations need to be made regarding what measures will be used, how many measures are needed, and how focused the measures need to be (Smith, 1996). When out- come measures are developed for assistive technology devices and services, it is important to be clear about who the stake- holders are in this process (DeRuyter, 1995). This is not as obvious a question as it first seems. If outcome measures are used to inform funding sources, are these funding sources consumers of the outcome results or stakeholders in the process? Likewise, providers may be considered either con- sumers or stakeholders, depending on the type of outcome measure used and the implications for its implementation. If user satisfaction is to be used as an outcome measure, is that a measure that relates to the provider, the funding source, or the user? Certainly the user of the technology is a consumer, but not all outcome measures are user centered. In the remainder of this section those measures that have been demonstrated to have reliability and validity in the measurement of outcomes at several levels are discussed.

Structure, process, and outcome measures in assistive technology delivery can be distinguished among. The struc- ture of the delivery system refers to aspects such as the staffing, staff expertise, equipment on hand, budget, and range of services provided. The process of assistive technology

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delivery includes the stages of assessment and intervention described in this chapter. Process measures ascertain whether these stages have occurred and whether the proce- dures meet an acceptable standard. Outcome measures evaluate the end result of the assistive technology interven- tion. Figure 4-7 illustrates the interrelationships among the assistive technology system, the service delivery process, and their outcomes.

There are a number of different levels at which we can evaluate the effectiveness of both devices and services by measuring outcomes. Traditionally, at the clinical level the question being asked is, did the intervention remediate the individual’s impairment? This is the impairment level of the ICF classification of the WHO (see Chapter 1). In the provision of assistive technologies, this level is seldom the major focus, but it is important because assistive technologies can lead to improvement in impairment and thus in function. The parallel interventions model (Angelo and Smith, 1989; Smith, 1991) described earlier in this chapter illustrates how intervention to affect the level of impairment is related to the use of assistive technologies. The next level is the functional level, when the question is, can the individual accomplish tasks that he or she could not do without the assistive tech- nology? This is the activity level of the ICF classification of the WHO. In this case, functional performance meas- ures are typically used to determine effectiveness.

When services were primarily clinical and delivered in institutional settings, measures of impairment and functional measures were the focus of outcome evaluation. However, over the past decade there has been a move toward community- based services in rehabilitation. This has been driven by rising costs of institutional care and is being addressed by shortening stays and transferring more care to the commu- nity. As described in this chapter, many services, including most of assistive technology services, are more appropriately delivered in the community where they will be used.

Community-based services are also being driven by an emerging alliance between the largely institution-based reha- bilitation establishment and the largely community-based

disability community. This alliance has implications for responsibility for care, including responsibility for choices of assistive technology devices and services (Lysack and Kaufert, 1999). As described in Chapter 1 and in this chap- ter, consumers play a larger role in decision making regarding what they receive and the evaluation of the quality of both the devices and services. The question being asked by the consumer at this level is, do the assistive technology services and devices provided meet my needs? To answer this ques- tion, user satisfaction measures related to assistive tech- nology services and devices have been developed.

As discussed in Chapter 1, the classification of disability over the past 20 years has begun to focus on its social dimen- sions (Fougeyrollas and Gray, 1998). This social model, now incorporated into the WHO ICF classification (WHO, 2001), provides a richer and more complete view of both disability and the role of assistive technologies in the lives of people who have disabilities. It is no longer important to achieve success only in the clinic or laboratory. The real test is in daily community use of the technologies. The question being asked at this level is, what is the impact of this assis- tive technology device or service on quality of life? The pri- mary outcome measures used for assessing the effectiveness of assistive technology devices and services in this broader social context are quality-of-life measures.

Each of these primary types of measurement of assistive technology device and service outcomes is discussed in the following sections.

Measuring Clinical and Functional Outcomes

In the past, health care and rehabilitation quality of service was measured by looking at factors such as timeliness and the completeness of the services provided (e.g., whether a discharge summary was completed for the consumer within 1 week of discharge). These are actually process measures, and they do not reflect outcomes of the assistive technology intervention. Within the past decade or so, rehabilitation service providers have begun to focus more on the functional

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Service Delivery Program

Modify Service Delivery Program

Measure Functional Outcomes

Assistive Technology System

C

A

H

T

Figure 4-7 Interrelationship among the assistive technology system, the service delivery process and structure, and their outcomes. H, Human; A, activity; C, context; T, assistive technology.

outcomes achieved by the consumer as a result of intervention. Because the focus of assistive technology practitioners is on reducing disability and maximizing an individual’s func- tional status, it is only natural that one of the factors to measure is functional outcome related to assistive device use.

There are a number of tools that have been developed and studied that measure functional outcomes of individuals who have been through the rehabilitation process. Examples of functional outcome measures include the Barthel Index (Mahoney and Barthel, 1965), the Klein-Bell ADL Scale (Klein and Bell, 1979), and the Functional Independence Measure™ (FIM) (Uniform Data System for Medical Rehabilitation, 1997).

Unfortunately, many of these traditional tools used in the field of rehabilitation do not document the efficacy of tech- nological intervention (Christiansen, Schwartz, and Barnes, 1988; Smith, 1996). As Smith (1996) points out, many instruments are limited in their scope in three ways: (1) they tend to be developed for a particular population, such as individuals who have sustained a stroke, (2) many instru- ments are developed for a particular health care setting, such as long-term care or acute rehabilitation settings, and (3) they frequently focus on a specific functional area, such as hand function or self-care.

Functional Independence Measure. The FIM™ Instrument is an example of one functional outcome measure. We have chosen the FIM™ as an example because it is widely used in assessing the outcomes of rehabilitation interventions. The FIM™ is based on a medical model of assessment that places importance on cure (Smith, 1996). The FIM measures the individual’s performance on 18 items under the categories of self-care, bowel and bladder management, transfers, loco- motion, communication, and cognition (Uniform Data System for Medical Rehabilitation, 1997). The scoring of the FIM™ is on a seven-point scale. The individual only obtains the full seven points if he or she does not require any assistance or assistive device to perform a function. Thus the FIM™ is not directly applicable to assistive device outcome measurement because its maximal score in any category can only be obtained if the person does not use any technology. Use of technology automatically implies that the person is not totally functionally independent. This appraisal of functional independence is inconsistent with the current view that an individual is inde- pendent if he or she can manage his or her own life (Smith, 1996). Another concern regarding the FIM™ and other tools that measure function is that they do not impart information regarding the impact of assistive devices on the quality of life of the user ( Jutai et al, 1996).

User Satisfaction as an Outcome Measure

Any discussion of assistive technology effectiveness must consider the recommended system and how well it meets the

consumer’s needs. Therefore, the measures must be con- sumer oriented, which means that the factors used to evalu- ate the effectiveness of assistive technology systems must be based on criteria that are important to the consumer. User satisfaction is the consumer’s perception of the degree to which the assistive technology system achieves the desired goal. This is a multidimensional phenomenon that requires qualitative measures (Demers, Weiss-Lambrou, and Ska, 1996). In addition, general user satisfaction scales are global, and they do not take into account various factors that affect a person’s use or nonuse of assistive technologies. In assistive technology applications, on the other hand, rating scales that address specific aspects of use are used (see Brooks, 1990, for example). For a large sample of users, these surveys can be statistically analyzed to determine the most impor- tant factors in achieving user satisfaction. These group sta- tistics may indicate a significant lack of satisfaction, and this information can be used to make changes in the service delivery structure and process to improve user satisfaction. For any individual assistive technology system, satisfaction is one parameter to be evaluated during the follow-up and fol- low-along processes. One limitation with satisfaction survey instruments is that they often “top out”; that is, individuals use either the highest or lowest score, and the range of a scale is lost. For example, assume that a five-point scale is used, with levels of “very dissatisfied,” “dissatisfied,” “neu- tral,” “satisfied,” and “very satisfied.” Most individuals will reduce this to a three-point scale, using the two ends and “neutral.” This is especially true if several parameters are measured with the same scale. Also, user satisfaction scales are one dimensional, measuring only satisfaction. Multidimensional scales can be more informative ( Jutai, personal communication, 2001).

Canadian Occupational Performance Measure. The Canadian Occupational Performance Measure (COPM) (Law et al, 1998) assesses the client’s perception of the importance of self-identified occupational performance goals and his or her satisfaction with that performance. The measure uses an interview format to identify goals in the areas of self-care, productivity, and leisure. The client rates the importance of each of these goals and their satisfaction. The instrument can be used before and after intervention. It is quite flexible because it allows the user to adapt the instrument for a specific purpose. The user can ask the client to think specifically of self-care, productivity, and leisure activities that he or she wants or needs to do when using a particular type of assistive technology. Miller Polgar and Barlow (2002) used this instrument as an outcome of seat- ing and mobility intervention. Its utility was somewhat lim- ited unless the client was asked to think about goals that specifically involved the use of assistive technology. This instrument has been used with many different client populations. Once the client becomes comfortable with

120 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

identifying his or her own goals, the COPM is a very useful outcome measure.

Quebec User Evaluation of Satisfaction With Assistive Technology. Five criteria were used in the development of the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) (Demers, Weiss-Lambrou, and Ska, 1996). The first is the recognition that user satis- faction is a multidimensional phenomenon that includes a broad range of variables, each of which can affect the user’s satisfaction with assistive technology. The second criterion relates to the inclusion of three types of variables: those involving the environment (context in the HAAT model), pertinent features of the person’s personality (the human), and the characteristics of the assistive technology itself. The third criterion is the recognition that the user should determine the relative importance of the satisfaction vari- able. This reflects the highly subjective nature of the user satisfaction measure. The fourth criterion provides for the user to express his or her opinion freely within the con- straints of an interview context. Finally, the QUEST was designed to be simple to understand and easy to use by ATPs when evaluating satisfaction. The QUEST requires approximately 30 minutes to administer and is guided by a three-part form.

The first part of the instrument is the general information questionnaire. This form is designed to determine the context in which the user’s satisfaction or dissatisfaction developed. It consists of 18 open-ended questions designed to include the three domains of environment (context [e.g., living arrange- ments, social supports, funding considerations]), user charac- teristics (human [e.g., sex, age, nature of disability, types of functional problems]), and assistive technology characteristics (e.g., when the device was acquired, frequency and patterns of use or nonuse, number and types of assistive technologies used).

The second part of the QUEST instrument is an assess- ment of satisfaction. This includes a set of 27 variables that represents the factors most likely to affect user satisfaction with assistive technologies. Each of the variables represents a specific category, but they are randomly ordered in the presentation to the user. This ensures that the user’s answers are not artificially influenced by the category of the question. Three tasks are used in this part of the evaluation. In the first task, the person is asked the degree of importance that he or she attributes to each variable. Each of the variables is printed on a card. There is a board for classifying the vari- able from very important (a score of 3) to no importance (0). The evaluator asks the user where he or she would like each card placed and then circles the response on the form. After completing the 27 variables, the user is given an opportunity to add other satisfaction variables that he or she feels are important. This task personalizes the assessment in terms of the individual’s preferences. The second task requires that the evaluator reorganize the variables according to the three

categories, and only the variables selected as being quite or very important (scores of 2 or 3) are included. For this task, a six-point scale (0 [very dissatisfied] to 5 [very satisfied]) portrayed on a semicircular dial is used. For each of the vari- ables included from Task 1, the user is asked to indicate his or her satisfaction by moving the dial or instructing the evalua- tor where to place it. The evaluator then circles the result on the summary form. Finally, the user is asked to express a global satisfaction score for the device. This task, as in Task 1, personalizes the assessment to the individual user. The third and final part of the QUEST requires that the evaluator reor- ganize the results from Part 2 into the three global categories (environment, person, and assistive technology). Only the val- ues for those variables rated as quite or very important in Task 1 are included. The summary sheet then serves to facilitate the interpretation and use of the data in assessing satisfaction and addressing those areas in which satisfaction is low.

Weiss-Lambrou et al (1999) used the QUEST to deter- mine satisfaction of consumers with seating aids. They describe the application of QUEST to this situation with a group of 24 subjects who used modular seating aids (see Chapter 6). They found that the most important variable (user comfort) was also rated as the least satisfying. This study illustrates the value and importance of a consumer- driven measure of user satisfaction. Weiss-Lambrou et al describe the application of QUEST in this context in detail.

Assistive Technology Abandonment. One of the most tangible indicators of lack of consumer satisfaction is when the consumer stops using a device although the need for which the device was obtained still exists. This situation is called technology abandonment, and it is useful to look at some of the factors that lead to it. Phillips and Zhao (1993) surveyed more than 200 users of assistive technolo- gies and identified four factors that were significantly related to the abandonment of assistive technologies: (1) failure of providers to take consumers’ opinions into account, (2) easy device procurement, (3) poor device performance, and (4) changes in consumers’ needs or priorities.

More recent research examined personal and social factors that predict assistive technology abandonment. Pape, Kim, and Weiner (2002) conducted a review of the literature related to assistive technology abandonment to look at how the per- sonal meaning attributed to assistive devices influences their integration into the user’s daily life.They found that psychoso- cial and cultural variables were primary factors in determining the meaning individuals assigned to assistive technology. In particular, their expectations of how the device would function, the social costs of using the device (i.e., cost/benefit of device use), and an outlook that disability did not define the user as a person were the primary factors that contributed to whether a person integrated assistive technology into his or her life (Pape, Kim, and Weiner, 2002). Reimer-Weiss and Wacker (2000) examined factors that predicated assistive technology

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use in individuals with disability. They found that the relative advantage of the assistive technology in the user’s life and the user’s involvement in the device selection process were predic- tors of device use or discontinuance.

Scherer et al (2005) have developed a group of measures that help determine the match between the individual and technology. The Matching Person and Technology assess- ment is described shortly. A recent study examined the validity of the assumptions that guided the development of this instrument. The results of the study supported these assumptions, specifically that personal characteristics related to mood, self-esteem, self-determination and motivation, and psychosocial characteristics related to friend and family support (as examples) were significant predictors of device use (Scherer et al, 2005). Collectively, the earlier studies of Phillips and Zhao (1993) and the more recent work of Pape et al (2002), Reimer-Weiss and Wacker (2000), and Scherer et al (2005) provide evidence that characteristics of the device, the person, and their environment predict whether the client will use a device or abandon it.

Quality of Life as an Assistive Technology Outcome Measure

ATPs, assistive technology suppliers, and assistive technol- ogy manufacturers often claim that their services or devices “improve the quality of life” of the consumer. This is an appealing concept. Who wouldn’t want to do this? There are, however, several difficulties with this concept when there is an attempt to actually measure it. In fact, the term quality of life is itself controversial and subject to misuse (Wolfensberger, 1994). Despite these limitations, it is tempt- ing to want to measure quality of life. It is being applied with increasing frequency to outcomes measurement in medicine and rehabilitation (Oldridge, 1996). In a medical service context, quality of life is often related to life expectancy and optimal life quality during the time a person is alive. In reha- bilitation the concept of quality of life takes on a bit of a dif- ferent meaning because the goal is not “repair” or cure but rather maximizing function and independence for the indi- vidual. In both cases the concept of health is important. The WHO defines health as “a state of complete physical, mental and social well-being, not merely the absence of disease” (WHO, 1948). Assistive technologies can certainly con- tribute to both quality of life and a healthy life. Measures designed to assess the degree to which this goal is achieved have begun to emerge over the past decade, and we are in a position to evaluate the assertion that a service or device actually does improve a consumer’s quality of life. Several measures of quality of life are discussed in this section.

Health-Related Quality of Life. The concept of health-related quality of life (HRQL) refers to the impact of health services on the overall quality of life of

individuals, and it represents the functional effect of an ill- ness and its consequent therapy on an individual as per- ceived by the person receiving the therapy (Oldridge, 1996). It measures one dimension of quality of life. Others are independence, income, adequate housing, and a safe envi- ronment. The definition of HRQL is “the value assigned to duration of life as modified by impairment, functional states, perceptions and social opportunities that are influenced by disease, injury, treatment or policy” (Patrick and Erickson, 1993; quoted by Oldridge, 1996). Rehabilitation in general, and assistive technologies in particular, addresses the long- term effects of disease and injury. Therefore both rehabilita- tion and assistive technology affect HRQL as defined here. However, as Oldridge points out, there are many instruments that have been developed to measure HRQL. Many of these are medically oriented and unsuited to assistive technology outcomes measurement. However, the general concepts underlying HRQL do have relevance to assistive technology outcomes measurement, and there is a need to develop new instruments that are more sensitive to the impact of assistive technologies on HRQL. Oldridge (1996) describes the types of HRQL measurements, their application, and the underly- ing principles on which this construct is based.

Psychosocial Impact of Assistive Devices Scale. To address the need for quality of life–related measures in assessing assistive technology outcomes, Day and Jutai (1996) developed the Psychosocial Impact of Assistive Devices Scale (PIADS). The development of the PIADS was based on information obtained through focus groups on the experiences of users of assistive technology (Day and Jutai, 1996). The initial set of constructs was developed and evaluated by a set of users. The scales were modified to include both positive and negative impacts on quality of life of assistive technology users by defining a scale from −3 (maximal negative impact) to +3 (maximal positive impact). The final version of the PIADS is a 26-item self- rating scale intended to measure the impact of rehabilita- tive technologies and assistive devices on the quality of life of the users of these products. Three subscales are included in the PIADS. These are competence (the effects of a device on functional independence, performance, and productivity), adaptability (the enabling and liberating effects of a device), and self-esteem (the extent to which a device has affected self-confidence, self-esteem, and emotional well-being). This multidimensional aspect of the PIADS contributes to its reliability and validity as a measure of the psychosocial impact of assistive technolo- gies on the consumer.

The PIADS has been applied to measurement of out- comes with a variety of assistive technologies. The original study focused on eyeglass and contact lens wearers (Day and Jutai, 1996). In subsequent studies it has been demonstrated that the subscales of the PIADS remain consistent over

122 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

populations and types of disabilities (stroke, amyotrophic lateral sclerosis, cerebral palsy) or types of assistive technolo- gies. For example, Jutai et al (2000) used the PIADS to eval- uate the psychosocial impact of EADLs (see Chapter 14). The goal of this study was to determine the perceived ben- efit of EADLs to the consumer’s quality of life. Two groups were included: users of EADLs and those for whom EADLs were appropriate but who had not yet received them. Users’ perceptions were measured at two points 6 to 9 months apart to determine the stability of the perception of psychosocial impact. Jutai et al found that EADLs pro- duced similar degrees of positive impact on users and posi- tive perceptions of anticipated impact on those without EADLs. The two measures of those using EADLs indi- cated that the psychosocial impact was stable over the time frame used. This study demonstrated the utility of the PIADS as an instrument for quantifying the psychosocial impact of assistive technologies.

Jutai et al (1996) discuss the use of instruments such as the PIADS to evaluate the outcomes of service provision in assistive technologies. The importance of quality-of-life outcome measures, in addition to clinical, functional, and user satisfaction assessments, is demonstrated through a series of case studies related to ease of implementation, clear definition of the desired outcomes, ethical considerations, and responsibility to the user of the assistive technology.

Matching Person and Technology Model. The Matching Person and Technology (MPT) model and assessment instruments have been developed to allow con- sumers to prioritize their own outcomes in relation to measurable changes in the perceived quality of life as opposed to the absence of disease or sickness or functional ability (Galvin and Scherer, 1996). This instrument has much in common with the QUEST and PIADS. The developers of the QUEST used the MPT as one of the theoretical bases for their work (Demers, Weiss-Lambrou, and Ska, 1996). As in these other measures, the MPT is a multidimensional instrument that taps domains related to overall impact on quality of life. Three domains are included in the MPT (Galvin and Scherer, 1996). The milieu dimension assesses characteristics of the environ- ment and psychosocial setting in which the assistive tech- nology is to be used. The personality dimension focuses on the individual’s personality, temperament, and preferences. Finally, the technology component addresses characteristics of the assistive technology itself. Like the QUEST and PIADS, the MPT is designed to be applied across a wide range of disabilities and assistive technology types. The multidimensional nature of the MPT makes it possible to separate influences of the technology, environment, and personal preferences. For example, a consumer may have characteristics (goals, skills, and abilities) typically associ- ated with assistive technology nonuse as measured by the

milieu/environment variable but may appear to be an optimal user according to characteristics identified for personality and technology. In this case the milieu/ environment influences may need to be addressed before the consumer can gain maximal benefit and satisfaction from the use of the assistive technology. Galvin and Scherer (1996) describe the MPT instrument and its application in detail. The MPT has been shown to have reliability and validity in determining the factors related to device abandonment and in assessing the impact on quality of life of assistive technology use.

Relationship of Outcome Measures to the Human Activity Assistive Technology Model

The framework used throughout this text is the HAAT model. This framework is useful in placing the various out- come measures described in an overall structure. Each HAAT element can be related to outcome measures. The activity defines the consumer goals to be achieved on the basis of a consideration of life roles, performance areas, and tasks. There may be several goals for one consumer because he or she has several different life roles (e.g., worker, parent, husband or wife). Goals that are defined form the basis for a consumer-driven outcome assessment. Important questions to be addressed in this domain include (1) was the goal achieved? how well was it achieved? (outcome measures) and (2) were the needs adequately addressed during the assessment to allow definition of goals? (process measure).

Constraints that are placed on the achievement of goals are defined by the HAAT context. This is directly related to the milieu of the MPT and the environment of the QUEST and the adaptability subscale of the PIADS. Outcome measures arising from the context include whether the system is able to function in the required con- texts and how well. These may relate to the physical con- text (e.g., heat or cold, bright light, noisy environment), settings (e.g., home versus employment), or social factors. The inclusion of social factors links the process to society as a whole through cultural considerations (see Chapter 2). One aspect of culture is the funding priorities that are mandated by society’s attitudes toward persons with dis- abilities. Society as a whole determines funding priorities. If the consumer obtains a system purchased though a par- ticular source, he or she is obligated to comply with the mandate of that funding source. For example, vocational rehabilitation agencies fund services and devices if they are related to employment, and a consumer who receives a computer from this source is obligated to use it for employment rather than for recreation. However, if a con- sumer uses his or her own money to buy the services or sys- tem, he or she can use them as she sees fit. Thus the funding source is linked to the assistive technology system

P A R T II Service Delivery in Assistive Technologies 123

through the social context. The area of funding is discussed further in Chapter 5.

The human component of the HAAT model is directly related to the personality dimension of the MPT, the self- esteem and competence subscales of the PIADS, and the personality feature of the QUEST. Each of these instruments taps a slightly different perspective on the human element of the HAAT model and relates to the overall perception of consumer satisfaction and improvement in quality of life as a result of the acquisition of an assistive technology system.

The desired assistive technology characteristics, the final element of the HAAT model, are defined by the combina- tion of consumer skills, goals, personality, and contextual constraints. The QUEST addresses these through its assis- tive technology characteristics criterion, the MPT through the technology dimension, and the PIADS through the adaptability subscale. These characteristics are based on the consumer tasks that must be accomplished; the personality, perceptual, and motivational characteristics; and the charac- teristics of the assistive technology relevant to device use or nonuse. Questions of importance that can be addressed by the various outcome instruments include (1) were the skills accurately determined? (2) were these characteristics able to accommodate for contextual constraints? (3) were the char- acteristics and associated tasks consistent with the con- sumer’s skills? and (4) if the identified tasks are successfully completed, is the goal achieved?

Process and structure can also be evaluated by determin- ing how well the needs and goals; human skills, perceptions, and motivation; and contextual constraints described by the HAAT model are identified. The assessment determines the human skills available to meet the goals. One typical process measure is how accurately these skills were determined. An example outcome measure is the degree to which these skills apply to the use of assistive technologies. For example, assume that it is determined during the assessment that a consumer can use a standard keyboard (see Chapter 7). By evaluation of his or her success in performing functional daily tasks with the keyboard, both the outcome and the process can be measured. If the consumer is physically unable to use the keyboard, then the assessment procedures must be reviewed to see whether the assessment process is sound. If the process is all right but an error in ATP judg- ment was made, then the structure needs to be altered by providing more staff training to increase the likelihood that correct recommendations will be made. When the effective- ness of training is being considered, a process goal, such as the degree to which the consumer has moved from novice to expert status with a given system, can be measured. Alternatively, the consumer may be able to use the keyboard physically, but the total system may not meet his or her needs, so the consumer may be dissatisfied with the overall result. This outcome will have an impact on process and structure as well, but it also may require revision in the system to make it functional.

Conclusions

The effectiveness of the assistive technology system and the efficacy of the ATP to provide services are both measured by their ability to meet the needs of the consumer. Obviously this is appropriate. However, it is easy to lose sight of this emphasis if a program is built from a perspective of “experts” providing a service for consumers rather than collaborating with the consumer, family, and others to meet a goal. The collaborative approach releases the ATP from the burden of having all the answers and accepting total responsibility. Responsibility for successful outcomes is shared with the consumer and others. This avoids the paternalistic protection of the consumer and empowers him or her to take responsi- bility for the outcome. Each member of the team becomes 100% responsible for success. This encourages cooperation, communication, and interaction, all factors that are essential for effective use of the system. The most effective service is operated from the point of view of establishing desired out- comes and then developing the structure and process to real- ize them. Too often ATPs and other professionals tend to protect their services from scrutiny rather than welcoming evaluation and its implications for improvement.

The development of appropriate process and outcome measures for assistive technology service delivery is still at an early stage. Since the mid 1990s, however, a number of new tools have been developed and validated and are now available for the ATP to use in evaluating the effectiveness of assistive technology systems. The outcome measures described in this chapter have been developed to allow determination of skills, abilities, and motivation; functional performance requirements and skill levels; consumer satisfaction with the recommended system; and overall impact on the quality of life of the con- sumer and significant others. Each of these measures has been developed and validated to focus on different aspects of assis- tive technology outcomes. As demonstrated, several of these have common characteristics. Work is under way to relate three measures, the PIADS, QUEST, and MPT, to each other and to develop a common understanding of the important variables leading to successful assistive device application and use ( Jutai, 2001). Continued research and development, par- ticularly on the psychosocial aspects of assistive technology use and nonuse, will continue to inform our assessment of out- come measures and the development of assistive technologies that are more effective in meeting the needs of consumers.

SUMMARY

This chapter describes the principles of assessment and inter- vention and the service delivery process to the consumer. The steps in the process include referral intake, needs assessment, evaluation, recommendation, implementation, follow-up, and follow-along.The current state of outcome measurement in the field of assistive technology is also discussed.

124 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

P A R T II Service Delivery in Assistive Technologies 125

Study Questions

1. Describe the five principles for assistive technology assessment and intervention.

2. Distinguish between quantitative and qualitative assess- ment procedures.

3. What are the four methods of gathering assessment information?

4. What is the difference between clinical and formal assessment procedures?

5. What is the meaning of the term criteria for service as used in assistive technology referral?

6. List the steps involved in assistive technology service delivery and write a brief description of each one. Which of these steps is the most important? Justify your choice.

7. Describe the difference between opportunity barriers and access barriers. Give an example of each.

8. List three types of opportunity barriers and how they can be addressed during the assessment process.

9. What consumer skills do we evaluate during the assis- tive technology skills assessment?

10. Describe the ideal relationship between the consumer and the assistive technology practitioner in the assess- ment and recommendation process for assistive tech- nologies.

11. What visual functions do we measure during the sen- sory assessment, and how does each of these apply to the use of assistive technologies?

12. Describe the major components of a physical evaluation. 13. What are the major areas that are assessed in the cogni-

tive evaluation for assistive technologies? Why do you think these areas were chosen?

14. Why is a separate “device characteristics” section included in the assessment? What are the outcomes of this portion of the evaluation?

15. Who are the audiences for the written assessment report? What challenges does this present?

16. Describe the major steps in implementation of an assis- tive technology system.

17. What are the major types of performance facilitators? When is each type used? What is the role played by each?

18. What are the major goals of a follow-up program, and how does this differ from follow-along?

19. What is the difference between repair and maintenance? 20. What are the three major domains in which outcome

measures are used in assistive technology service delivery? 21. How do the three measurement domains of Question

20 relate to an improvement in the service delivery process?

22. What are the limitations in the use of the Functional Independence Measure™ Instrument for assessing the outcome of assistive technology interventions?

23. What are the strengths of the COPM in relation to determination of consumer needs and satisfaction?

24. Describe the major features of the QUEST and how it is used to assess user satisfaction.

25. What are the most common reasons that consumers abandon technology?

26. What is the HRQL, and how is it related to assistive technology outcome measures?

27. What are the three subscales of the PIADS? Why does the inclusion of these three scales increase the useful- ness and validity of the PIADS?

28. Describe the relationship of the four HAAT model components to the outcome measures described in this chapter.

29. What are the roles and responsibilities of the ATP in determining the effectiveness of assistive technology services and devices?

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Nunnally JC, Bernstein IH: Psychometric theory, ed 3, Toronto, 1994, McGraw-Hill.

Oldridge NB: Outcomes measurement: health-related quality of life, Assist Technol 8:82-93, 1996.

Pallin M: Techniques for the successful use of augmentative com- munication systems. Presented at Demystifying Technology Workshop, Sacramento, CA, 1991, Assistive Device Center.

Pape TL, Kim J, Weiner B: The shape of individual meanings assigned to assistive technology: a review of personal factors. Dis Rehabil 24:5-20, 2002.

Patrick D, Erickson P: Health status and health policy: quality of life in health care evaluation and resource allocation, New York, 1993, Oxford University Press.

Phillips B, Zhao H: Predictors of assistive technology abandon- ment, Assist Technol 5:36-45, 1993.

Reimer-Weiss ML, Wacker RR: Factors associated with assis- tive technology discontinuance among individuals with disabilities. J Rehabil 66:44-50, 2000.

Russel DJ et al: Gross motor function measure, Cambridge, 2002, Cambridge University Press.

Sackett DL: Evaluation of health services. In Last JM, editor: Mosley-Rosenau’s public health and preventive medicine, ed 11, New York, 1980, Appleton-Century-Crofts.

Scherer M: Matching person and technology: a series of assessments for evaluating predispositions to and outcomes of technology use in rehabilitation, education, the workplace and other settings, Webster, NY, 1998, Institute for Matching Person and Technology.

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Smith RO: Technological approaches to performance enhance- ment. In Christiansen C, Baum C, editors: Occupational therapy, Thorofare, NJ, 1991, Slack.

126 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

Smith RO: Measuring the outcomes of assistive technology: challenge and innovation, Assist Technol 8:71-81, 1996.

Sprigle S, Abdelhamied A: The relationship between ability measures and assistive technology selection, design, and use. In Gray DB, Quatrano LA, Lieberman ML, editors: Designing and using assistive technology: the human perspec- tive, Baltimore, 1998, Paul H Brookes.

Stapelton D, Garrett R: VOCAselect version 1.0: an AAC device selection tool, Proc Aust Conf Technol People Disabil 114-116, 1995.

Stapelton D et al: Computer access selector: a tool to assist in the selection of computer access devices, Proc Aust Conf Technol People Disabil pp 129-131, 1995.

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Weiss-Lambrou R: Wheelchair seating aids: how satisfied are consumers? Assist Technol 11:43-53, 1999.

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P A R T II Service Delivery in Assistive Technologies 127

Sample of a Written Questionnaire

128

A P P E N D I X 4 - 1 A

P A R T II Service Delivery in Assistive Technologies 129

BACKGROUND INFORMATION QUESTIONNAIRE

This questionnaire will help us in providing the services that the client may need. Please answer all applicable questions and return the form as soon as possible so that an evaluation may be scheduled.

Form completed by:

Client’s name:

Address:

City/State/Zip:

Language(s) spoken:

Please mark the ethnic group that applies (optional):

Asian

Caucasian

Home:

Skilled Nursing Home

Professional

Communication

Postural Seating/Wheelchair

Pressure Management/Wheelchair Powered Mobility

Environmental Control

Ergonomics (Work Site)

Lease/Rent Device

Repair Device

Other

Friend Conference Yellow Pages Other

Rehab Facility Extended Care Facility Other

Group Home

American Indian

Hispanic

African American

Other

Spouse/parent/guardian:

Address:

City/State/Zip:

Referred by:

Address:

Phone:

How did you learn about our services?

Reason for Referral:

Residence:

Alone With Family With Attendant

Relationship to client:

Date:

Birth date:

Phone:

Phone:

General Information

Referral Information

Goals/Expectations:

Relationship to client:

Computer Access

130 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

Primary Diagnosis

Medical/Health Information

Sensory/Perceptual Abilities

Amyotrophic Lateral Sclerosis

Traumatic Brain Injury

Muscular Dystrophy

Multiple Sclerosis

Spinal Cord Injury

Stroke

Cerebral Palsy

Developmental Delay

Emotional/Behavioral Disability

Learning Disabiltiy

Cognitive Impairment

Hearing Impairment

Seizures

Other

Other Condition

Onset Dates Specifics/Comments

Level:

Anticipated Course of Condition:

General Health Condition: Medications: List any joint dislocations, deformities, other orthopedic problems, and past or pending surgeries:

Services Currently Receiving:

Stable

Excellent

Improving

Good

Deteriorating

Fair

Fluctuating

Poor

OT

Yes No

Yes No

Yes No

Yes No

Yes No

Yes No

Yes No

Yes No

Yes No

Yes No

Yes No

Yes No

PT Speech Therapy Other

Vision

Visual deficits?

Wear glasses or corrective lenses?

Perceptual deficits?

Lighting affect vision?

Can fixate vision on stationary object?

Can follow a moving object?

Can look right/left without moving head?

Preference for placement of objects?

Hearing

Known hearing loss?

Wears hearing aid?

Reacts to sounds?

Understands speech?

Comments:

Comments:

Comments:

Comments:

Comments:

Comments:

Comments:

Where in visual field?

If yes, include audiology results

Comments:

Comments:

Comments:

P A R T II Service Delivery in Assistive Technologies 131

Activities of Daily Living

Social Interaction, Learning, and Behavior

School:

Day Program:

Work:

Other Program:

No interest in surroundings

Little interest in surroundings

Sometimes observant; sometimes sees humor in situations

Unoccupied behavior

Onlooker behavior

Play among others; little interaction

Interaction with other peers

Solitary independent play

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

No

No

No

No

Very alert; observant; sees humor in situations

Full Time Part Time

Full Time Part Time Grade Level

Days per Week

Position

Please indicate how many hours per day are spent in the following:

a regular chair/couch

powered wheelchair

lying in bed

other

Choose one that best describes level of alertness:

For children, choose one that best describes his/her social play:

Sit and concentrate on a task for appropriate amount of time?

Concentrate within a distracting environment?

Make eye contact with people and/or tasks?

Classify different objects into categories?

Carry out tasks of 2 or more steps?

Understand concept of direction? (i.e., up, down)

Know his/her actions can cause something else to happen?

Make choices when 2 objects or activities are presented?

Follow directions or commands given?

List activities/objects/people that the client finds motivating or interesting.

driving/riding in a car

standing unsupported

sitting on the floor/mat

a manual wheelchair

standing frame

sitting at a desk

Hrs. Hrs.Hrs.

Can he/she:

Comments about social behavior:

132 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

Functional Abilities

Independent

Independent

Independent

Independent

If assisted:

Assisted

Assisted

Assisted

Assisted

Two-Man Lift

Dependent Tube Feed Electric Feeder

Dependent

Dependent

Dependent

Sliding Board Stand-Pivot

Feeding:

Dressing:

Transfers:

Chewing/ Swallowing:

Motor Skills

Yes

Yes

No

No

No

No

No

No

Does the client have motor control in the following:

Eyes

Neck/Head

Yes

Yes

Right Arm

Right Hand

Yes

Yes

R L Point with a finger R L

L

L

R

R

Type with more than one digit

Hold objects

Type with head or mouthstick

L

L

Write with pen or pencil

R

R

Forward Sideways Backward

Type with one digit

Grasp/release object

Use both hands for a two-handed activity

Reach capabilities:

Incoordination/poor balance

Tone: Too little Too much Reflexes

Endurance/fatigue

Joint contractures

Tremor

Yes

Yes

No

No

No

No

No

No

Yes

Yes

Yes

Yes

NoYes

Right Leg

Right Foot

Which part of the body is best controlled?

Are there any positions or supports that help control movement?

Please mark all capabilities below (and dominant side when applicable):

Problems that may interfere with motor function:

Mouth

Trunk

Left Arm

Left Hand

Left Leg

Left Foot

If yes, describe:

P A R T II Service Delivery in Assistive Technologies 133

Mobility/Positioning

Sits independently in regular chair

Sits in wheelchair without support

Sits in wheelchair with support (describe below)

Manual Wheelchair:

Brand Name/Manufacturer:

Model:

Funding Source:

How Propelled:

Type/Description of Seating System:

Accessories (e.g., Laptray):

Problems with Wheelchair:

Power Wheelchair:

Joystick Sip & Puff Chin Switch Switch Array

Hand Head

No

Car

Van/bus for wheelchairs

Family van

Public transportation

Day program’s vehicle

Paratransit

Yes

Foot Other

Hands Feet Assisted/Dependent

Unable to sit upright

Walks independently

Walks with assistance

Depends on wheelchair for mobility

Check all that apply:

(Used Where? )

Date Obtained:

Brand Name/Manufacturer:

Model:

Funding Source:

Controlled By:

Control Site:

Type/Description of Seating System:

Accessories (e.g., Laptray):

Problems with Wheelchair:

(Used Where? )

Date Obtained:

Is there a history of pressure sores?

Please check all means of transportation that are used:

No Yes)(Current?

134 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

Communication Skills

Speech

Gestures Eye Gaze Facial Expressions

Sign Language

Pointing

Handwriting Drawing Typing

Pictures Words Letters)Communication Board or Notebook:

Electronic Communication Device:

Symbols Used: How long has this device been used?: Is this successful/How successful has it been?

What is the client’s means of indicating “YES”:

Can the client spell?

Is communication spontaneous?

To whom can the client reliably communicate the following:

Attract attention

Pain/discomfort

Frustration/happiness

Hunger/thirst

Fatigue/boredom

Refusal

Choice of items

Convey new information

Pictures Words

Yes

Yes

Discuss past/future events

Can the client convey medical needs to professionals?

How would you like to see the client’s communications skills improve?

No

No

Letters No. of Symbols

Yes No

Select all methods used to communicate:

Sounds Single Words

To All Listeners

Phrases Whole Sentences

Only to Familiar ListenersIntelligibility:

Type: Number of signs used List 5 most commonly used signs

ASL

Approx. size of symbols

SEE Other

(Symbols Used: Number of symbols used

(Approx. grade level )

All Friends Family/Caregiver No One Method:

“NO”:

(How? with finger? foot? eye gaze? )

Assessment Forms

135

A P P E N D I X 4 - 1 B

INITIAL EVALUATION FORM ASSESSMENT SECTION

I. Motor A. Grasps

1. Finger, hand, and wrist movement a. Check the following finger/hand movement functions for both the right (R) and left (L) hands. For numbers 1, 2

(or 2a) and 3, place the object on the table and ask the person to hand it to you. If the person cannot pick the object up, then hand it to him or her. For numbers 4, 5, and 6, hold the object in a comfortable location oriented as shown and ask the person to grasp it, move it from front to back and side to side, and release it. For number 7, place the push button on the table and ask the person to press it. Place a number in the box as follows: 1, poor; 2, fair; and 3, good.

136 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

B. Range: Hand

Present hand range sheet. Locate the sheet with the client’s midline centered on square 8.

The squares are numbered and each corner is lettered as shown. The targets are the corners. Use the sequence: touch the square then 1A/1B/1C/1D and repeat for all squares within the person’s range. Circle locations reached. For children, it may be necessary to use the smaller (foot) range sheet.

Compare your impression of the time required to reach the square (tracking time) to the time required to move among the corners A, B, C, D (select time).

Use the distance table (see Figure 4-5) to fill in the following block.

P A R T II Service Delivery in Assistive Technologies 137

C. Body part movement and control

For each movement requested place a + (present) or − (absent) in the appropriate column. Note whether required move- ment can be initiated (I), controlled (C), and terminated (T).

138 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

If adequate arm and hand movement are available, omit the following tasks:

D. Range: Foot

Present the foot range sheet unless the interview indicates there is no foot movement possible or hand movement is adequate. If foot control appears to be feasible, then repeat the same tasks that were done with the hand. Start by locating the heel of the foot at the site labeled “X.” Allow the person to move the entire foot as necessary to complete the task.

P A R T II Service Delivery in Assistive Technologies 139

E. Head control

Measure range of movement in the planes shown. Check the space representing the person’s degree of movement to indicate if he or she has no movement, partial movement, or full range of movement.

140 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

Directions

Is a headpointer used now? ________________________ If so, describe: ________________________________________

_____________________________________________________________________________________________________

If the client has used one before but doesn’t now, explain why: __________________________________________________

_____________________________________________________________________________________________________

Reflexive head movements noted: _________________________________________________________________________

_____________________________________________________________________________________________________

Restraints to head movement: ________________________ ________________________

Sketch

List those anatomical sites appearing to be most suitable for interfacing

Movement plane left right

None Partial Full None Partial Full Comments

Horizontal

Up Down

Vertical

Left Right

Tilt

Head

Most suitable __________________________________________________________ Next most suitable ______________________________________________________ Third most suitable ______________________________________________________

II. Symbol Location, Type, and Size A. Symbol location task

1. Peripheral Instruct the person to keep head and eyes fixed straight forward. Ask the person to indicate when he or she can see your finger or pointer without moving his or her eyes. If the person cannot keep the eyes fixed, provide an object to stare at. Start with your finger or pointer approximately 12 inches from the side of his/her head (at the ear) and move it around the head toward the face. Mark the areas in which the person can see your finger.

2. Tracking Using your finger or pointer, have the person track horizontally at the level of the eyes. Begin at the nose and go left/right. To track vertically, begin at the nose and go up/down.

Yes Comments

Can the person track horizontally? __________ _____________________________________

Can the person track vertically? __________ _____________________________________

B. Symbol size verification 1. Instructions

Select the stimuli according to the information available. If information is lacking, begin with a more “basic” sym- bol system (e.g., select pictures over words or letters) and begin with the largest size set. Place the stimuli approxi- mately 18 inches from the subject’s eyes. Determine the method of selection and explain it to the consumer.

P A R T II Service Delivery in Assistive Technologies 141

Present two stimuli to the consumer and say, for example, “Please point to (look at) the comb,” or “Is this a comb?” Three trials should be run. If no errors are made, the size of the stimuli should be reduced, with three trials run at each size tested. A more advanced symbol system may then be tested if appropriate. If some errors are made, a more basic symbol system should be tested and the positioning of the stimuli should be reexamined.

2. Data sheet Use a plus mark in the choice column to designate a correct response and use a circle to designate an error. Be sure to note a symbol system and stimulus size for all trial groups.

Trials + �

Symbol System Size Correct/Incorrect a. –––––––––––––––––––––––– –––––––––––––––– 1. ––––––––––––––––––––––––––––––––

2. –––––––––––––––––––––––––––––––– 3. ––––––––––––––––––––––––––––––––

b. –––––––––––––––––––––––– –––––––––––––––– 1. –––––––––––––––––––––––––––––––– 2. –––––––––––––––––––––––––––––––– 3. ––––––––––––––––––––––––––––––––

c. –––––––––––––––––––––––– –––––––––––––––– 1. –––––––––––––––––––––––––––––––– 2. –––––––––––––––––––––––––––––––– 3. ––––––––––––––––––––––––––––––––

d. –––––––––––––––––––––––– –––––––––––––––– 1. –––––––––––––––––––––––––––––––– 2. –––––––––––––––––––––––––––––––– 3. ––––––––––––––––––––––––––––––––

142 C H A P T E R 4 Delivering Assistive Technology Services to the Consumer

If you were not able to establish an optimal stimulus, explain why.

Optimal symbol type: ___________________________________________ Optimal size: __________________________________________________

Funding Assistive Technology Services and Systems

Chapter Out l ine

PUBLIC SOURCES OF FUNDING U.S. Public Sources of Assistive Technology Funding Medicare Medicaid Children’s Medical Services Programs for the Developmentally Disabled Tricare (formerly CHAMPUS) Education Vocational Rehabilitation Plan for Achieving Self-Sufficiency Department of Veterans Affairs Workers’ Compensation Canadian Provincial and Territorial Sources of Assistive

Technology Funding Canadian Federal Sources of Assistive Technology Funding Health Canada—First Nations and Inuit Health: Uninsured

Health Benefits Veterans Independence Program Opportunities Fund for Persons With Disabilities Australian State Government Funding Schemes Australian Commonwealth Funded Schemes for the

Older Person Australian Department of Veterans’ Affairs—Rehabilitation

Appliances Program

Australian Motor Vehicle Compulsory Third Party Personal Injury Insurance

Australian Government Education Departments

PRIVATE SOURCES OF FUNDING Self-Funding Private Health Insurance

OTHER SOURCES OF FUNDING

FUNDING PROCESS AND GUIDELINES FOR PROCURING FUNDING

IDENTIFYING THE FUNDING SOURCE

JUSTIFYING FUNDING FOR ASSISTIVE TECHNOLOGY SERVICES AND DEVICES

APPEALING THE FUNDING DENIAL

BILLING AND CODING FOR SERVICES

PAYMENT PRACTICES

SUMMARY

APPENDIX 5-1: SAMPLE FORMS FOR DOCUMENTING CONSUMERS’ EQUIPMENT NEEDS

143

C H A P T E R 5

Learning Objectives

On completing this chapter, you will be able to do the following:

1. Identify the major categories of funding for assistive technology services and equipment 2. Describe the types of assistive technology devices and services covered by each category of funding 3. Distinguish between categories of funding as they relate to specific consumer characteristics

A s discussed in Chapter 1, there is an establishedassistive technology industry that provides services anddevices for individuals with disabilities. Evaluation, implementation, and maintenance and repair of assistive technologies can be costly, and most consumers do not have the financial resources available to purchase the necessary services and equipment. Therefore, funding by third-party sources is necessary for individuals to procure assistive tech- nology services and equipment. Fortunately, funding for many assistive technology services and devices is widely available, and accessing that funding is generally a matter of following a straightforward process. Assisting with the acquisition of this funding is an inherent part of the assistive technology practitioner’s (ATP) role as a service provider.

In most countries assistive technology services and devices are funded by numerous sources rather than by a sys- tem solely dedicated to the funding of assistive technology services and equipment. For any given individual, equipment and services may be funded solely from one source or through a combination of sources. Funding for assistive technology is usually rendered through agencies that have been primarily developed for the provision of other types of health, education, or social services programs.

In this chapter funding for assistive technologies in several countries (United States, Australia, and Canada) is described. Funding programs in these countries are representative of those in many other countries with local modifications of ele- ments of the programs. The various funding sources can be categorized as three general types: public, private, and other.

PUBLIC SOURCES OF FUNDING

U.S. Public Sources of Assistive Technology Funding

Public funding sources for assistive technology funding in the United States include federal, state, and local government agencies; several public sources of funding are listed in Box 5-1. There are more than 30 programs established by the U.S. Congress that affect U.S. residents with disabilities and more than 12 agencies on the federal level that oversee these programs

(Morris and Golinker, 1991). Typically, Congress authorizes funding through a specific piece of legislation, such as the Medicare Act, and designates a federal agency to determine the scope and criteria for the program. Other programs are examples of a principle called “cooperative federalism.” For them, Congress passes a law that is broadly administered by a federal government agency but administered on a day-to-day basis by the states. These programs also will be jointly funded by the federal and state governments. Medicaid and vocational rehabilitation are examples of cooperative federalism programs. A third model extends the federal presence to local levels of government where day-to-day decision making occurs. The Individuals With Disabilities Education Act (IDEA), which sets standards for the education of children with disabilities by local schools, is an example of this type of program.

Medicare. Medicare is the health insurance program operated by the federal government. Coverage, benefits, and program operation for this program are described in Chapter 1. Medicare funds durable medical equipment (see Chapter 1 for definition). Some assistive technology equipment, such as speech-generating devices, the full range of mobility aids and accessories, hospital beds, and patient lifts, are covered under Part B as durable medical equipment.

Medicaid. Medicaid is a public welfare program whose coverage, benefits, and program operation are described in Chapter 1. Assistive technology services and devices are within the scope of each state’s Medicaid program (Golinker and Mistrett, 1997). The federal definitions of the intent and scope of mandated and optional services should be used as a starting point to determine the basis of Medicaid funding for assistive technology. To receive federal funding for Medicaid, all states must comply with these definitions of services. Golinker and Mistrett (1997) identify 11 services among the list of mandatory and optional Medicaid services under which funding for assistive technology and services may qualify (see Box 1-3). These services are early and periodic screening, diagnostic treatment services; home health care

144 C H A P T E R 5 Funding Assistive Technology Services and Systems

Key Terms

Appeals Process Diagnosis Codes Fee for Service Managed Care Medicaid

Medical Necessity Medicare Plan for Achieving Self-Sufficiency

(PASS) Procedure Codes

Public Funding Sources Third-Party Payer Tricare

4. Describe the process for procuring funding 5. Describe the process by which funding decisions can be appealed

services, prosthetic devices; occupational therapy; physical therapy; speech-language pathology; rehabilitative services; preventive services; skilled nursing facility; and services and intermediate care facility services for persons with mental retardation, developmental disabilities, and related conditions. Because assistive technology devices and services are not listed as such in the Medicaid vocabulary, it is recommended that use of these terms be avoided when applying for funding under Medicaid (Golinker and Mistrett, 1997). Instead, the device being requested should be identified by its specific name in all documentation and any descriptive terms used should match those in the definition of one of the Medicaid services listed above.

One of the general criteria for funding of all Medicaid services is that the requested equipment or service be considered a medical necessity. Another general criterion for funding of Medicaid services is that prior approval or authorization is

required for nearly all services and equipment. Before com- mencing any services or purchasing any equipment for a Medicaid beneficiary, the ATP needs to request approval from Medicaid for the purchase of such services or devices. In some states a certain amount of occupational and physi- cal therapy services may be provided without prior authori- zation. Because the ATP may not know whether this threshold has already been reached, it is generally safer from a reimbursement standpoint to get prior approval for the services to be provided.

Children’s Medical Services. Medical and related services are provided to children under the age of 21 years who have chronic disabling conditions and who meet income limitations. These services are funded by the federal government under Title V of the Social Security Act. All children are eligible for medical diagnosis and evaluation.

P A R T II Service Delivery in Assistive Technologies 145

BOX 5-1

PUBLIC PROGRAMS Medicare Medicaid

Required and optional services Intermediate care facilities for persons who are mentally

retarded Early and periodic screening, diagnosis, and treatment Home- and community-based waivers Community-supported living arrangements

Maternal and child health Maternal and child health block grant to states Children with special health care needs Special projects of regional and national significance

Education Individuals with Disabilities Education Act state grants (Part B) IDEA programs for infants and toddlers with disabilities and

their families (Part H) State-operated programs Vocational education Head Start

Vocational rehabilitation State grants Supported employment Independent living Parts A, B, and C

Social Security benefits Title II: Social Security Disability Insurance Title XVI: Supplemental Security Income Work incentive programs

Developmental disability programs Department of Veterans Affairs programs Older Americans Act programs

ALTERNATIVE FINANCING Revolving loan fund Lending library Discount program

Low-interest loans Private foundations Service clubs Special state appropriations State bond issues Employee accommodations program Equipment loan program Corporate-sponsored loans Charitable organizations

U.S. TAX CODE Medical care expense deduction Business deductions Employee business deductions Americans with Disabilities Act credit for small business Credit for architectural and transportation barrier removal Targeted jobs tax credit Charitable contributions deduction

PRIVATE HEALTH INSURANCE Health insurance Workers’ Compensation Casualty insurance Disability insurance

CIVIL RIGHTS Americans with Disabilities Act Rehabilitation Act, Section 504

UNIVERSAL ACCESS Rehabilitation Act, Section 508 Decoder Circuitry Act

TELECOMMUNICATIONS Telecommunications for the Disabled Act of 1982 Telecommunications Accessibility Enhancement Act of 1988

U.S. Assistive Technology Financing Options

From the National Council on Disability: Study on the financing of assistive technology devices and services for individuals with disabilities, Washington, DC, 1993, The Council.

In some states, funding of assistive technologies is provided by Children’s Medical Services.

Programs for the Developmentally Disabled. Within each state, programs for the developmentally disabled provide a range of services, including case management, advocacy, community living, and purchase of other services. Assistive technology services and equipment may be funded from these programs.

Tricare (formerly CHAMPUS). The Tricare program, formerly known as the Civilian Health and Medical Program of the Uniformed Services (CHAMPUS), is a federally funded program that provides medical benefits to active duty military service members and their dependents and to military retirees and their dependents. Tricare contracts with various health insurance companies to administer this program, which provides medically necessary equipment and assistive technology services.

Education. As discussed in Chapter 1, the Education for All Handicapped Children Act of 1975, the Handicapped Infant and Toddlers Act of 1986, and the 1991 reauthorization of these statutes through IDEA are vehicles through which assistive technology and related services can be provided to children with disabilities. Children from birth to 2 years of age must have an Individualized Family Service Plan (IFSP), and children 3 years to 21 years old must have a written Individual Education Plan (IEP) (see Chapter 1). Assistive technology must be considered in the development of the child’s IEP. If assistive technology is identified as being necessary for a “free and appropriate public education,” it must be included in the IEP and this service must be provided.

Vocational Rehabilitation. The federal government provides states with funds to administer programs that help individuals with disabilities to enter, remain in, or return to employment. An Individual Plan for Employment (IPE, formerly called an Individual Written Rehabilitation Plan) that outlines the individual’s vocational objectives and services to be provided is required. Those who need assistive technology to complete training in a vocational rehabilitation program or to obtain or retain employment (competitive, supported, or sheltered) are eligible for funding of assistive technology equipment and services. Statutory amendments to this program create a strong presumption that an employment outcome always is possible, if the right services, including assistive technologies, are provided. For this reason, greater attention is expected to be directed to developing services plans and vocational outcomes for individuals with more severe disabilities. However, staff of vocational rehabilitation programs may not be aware of the benefits of assistive technology, and efforts by ATPs to

provide continuing training can increase their awareness regarding assistive technology.

Plan for Achieving Self-Sufficiency. The Plan for Achieving Self-Sufficiency (PASS) is a program that allows individuals to put aside income for equipment or services that will assist them in achieving a vocational objective. This includes assistive technology services and devices such as augmentative communication devices and adapted computer equipment. The Social Security Administration oversees this program and must approve the PASS before it can go into effect. The Social Security Administration excludes the money earned to pay for the devices from earned income, which allows the consumer to continue to receive applicable benefits. The consumer develops a written plan that identifies needs and feasible occupational goals, with a timetable for attaining these goals.

Department of Veterans Affairs. The Department of Veterans Affairs (DVA), formerly the Veterans Administration (VA), directly provides assistive technology equipment and related services and contracts with outside programs to provide these services. Individuals who have a service-connected disability are eligible for purchase of assistive technologies by the VA.

Workers’ Compensation. Expenses incurred as a result of work-related injuries are covered by Workers’ Compensation benefits. Under certain conditions, equipment, home modifications, and services are covered. Workers’ Compensation benefits are financed jointly by individual employers or groups of employers and state governments (Burton, 1996). A designated state agency or board develops the regulations for Workers’ Compensation and private insurance companies typically administer the program.

Canadian Provincial and Territorial Sources of Assistive Technology Funding*

In Canada the delivery of health services is the responsibility of the provinces and territories. Although there are federal programs, most assistive technology funding is allocated and managed at the provincial/territorial level. Most federal programs have clauses about funding only what the provinces and territories do not fund. Table 5-1 shows the breakdown of public funding sources for assistive technologies in Canada by jurisdiction. It is clear that there are major differences in programs across the country. In general, funding

146 C H A P T E R 5 Funding Assistive Technology Services and Systems

*Deb Finn of the Assistive Devices Industry Office, Industry Canada, made major contributions to the sections on Canadian funding.

P A R T II Service Delivery in Assistive Technologies 147

Canadian Public Funding Sources by Province or Territory

Province/ Territory and Relevant Special Conditions Departments Assistive Devices Funded or Program Features Eligibility Web Links

Alberta: Back supports, bathing and Cost share: 25% of cost Disability lasting 6 months http://www.seniors.gov. Alberta Aids To Daily toileting equipment, of benefits, maximum or more, a chronic illness ab.ca/AADL/index.asp Living electrolarynx, hearing aids, $500 per family per or a terminal illness,

orthotic braces, prosthetic benefit year, clients on Alberta resident, valid devices, specialized seating income supplement Alberta Personal Health devices, speech-generating programs and those Care Number communication devices, with low income are wheelchair cushions, exempt from cost wheelchairs (manual and sharing power), walkers

British Columbia: Alternate positioning devices, Programs for children New or good quality www.mcf.gov.bc.ca/ At Home Program bathing and toileting aids, under 17 years recycled devices, at_home/ Set BC hearing aids, lifts, mobility (At Home, Set BC) and www.setbc.org Red Cross Aids equipment, orthotics and low-income homes http://www.redcross.ca/

to Independent bracing, specialized car and active in their article.asp?id=011086 Living Program seats, speech-generating communities and &tid=078 (AILP) devices, scooters, participate in social

wheelchairs, and walkers activities Manitoba: Prosthetics and orthotics, $75 deductible Prescription by a medical http://www.gov.mb.ca/

Prosthetics and hearing aids, adapted practitioner health/mhsip/ orthotics, hearing aid, telephones, TTY

telecommunications New Brunswick: Canes, crutches, hearing aids, Senior (65 years and A health card with http://www.gnb.ca/0017/

Seniors’ raised toilet seats, tub over) residing at home, rehabilitation equipment Health%20Services/ Rehabilitation transfer benches, grab bars, special care home, or as an eligible benefit, index-e.asp Equipment Program walkers, wheelchairs, drop nursing home, whose medical necessity TESS: Health Services seats, wheelchair accessories care is subsidized and goal is to assist persons Program, Training (trays, brake extensions, who is in financial with disabilities to obtain and Employment and cushions), speech aids need or resume employment Support Services (TESS)

Newfoundland and Orthotics and equipment, To alleviate the costs of Clients who meet the http://www.gov.nf.ca/ Labrador: walkers, lifts, hearing aids, supportive health financial eligibility criteria, health/

Special Assistance power wheelchairs and services for clients in payer of last resort scooters, manual the community that wheelchairs, custom seating would ordinarily be a systems, noncustom seating benefit extended to components and accessories, persons in hospitals or augmentative and nursing home alternative communication

Northwest Seniors: Registered with the Payer of last resort http://www.hlthss.gov. Territories: Prostheses, hearing aids, NWT Health Care nt.ca/ Extended Health manually operated Plan, permanent NWT Benefits for Seniors wheelchairs, walking aids, resident, be

Extended Aid for grab non-Native or Metis, Specified Diseases Specified diseases: have a specified

Prosthetic appliances, disease communication aids (hearing and telephone aids, bliss board), walkers, crutches, canes, manual and electric wheelchairs, wheelchair trays, transfer boards, armrests, cushions, seating inserts, transfer bars,

TABLE 5-1

Continued

148 C H A P T E R 5 Funding Assistive Technology Services and Systems

Canadian Public Funding Sources by Province or Territory—cont’d

Province/ Territory and Relevant Special Conditions Departments Assistive Devices Funded or Program Features Eligibility Web Links

toileting aids, patient lifters, grab bars, bars, other equipment or devices that are medically necessary (may be covered on a case-by-case basis)

Nova Scotia: Wheelchairs Approved residents Regular bed resident of a https://www.gov.ns. Specialized (specialized/custom) plus may be required to Department of Health long- ca/health/ccs/ltc.htm Equipment Program accessories, scooters, pay a monthly income- term care facility; requires (SEP) specialized transfer aids based fee for the covered equipment, has

Department of (e.g., transfer boards), equipment being been assessed by an Health service walkers, resident-specific provided through occupational or physical program available lifts/slings the SEP therapist and administered through the Canadian Red Cross

Nunavut Assistive devices are usually Most people in Nunavut See Non-insured benefits, acquired through third-party are covered with Health Health Canada in Table 5-2 insurance Canada’s Non-Insured

Health Benefit (Table 5-2) Ontario: Communication devices: Most devices must be Eligibility includes any http://www.health.

Assistive Devices Electrolarynges, authorized by a Ontario resident who has gov.on.ca/english/ Program communication boards, qualified health care a valid Ontario Health card public/program/adp/

mounting systems, signaling professional registered and who has a physical adp_mn.html aids, teletypewriters for the with the program. disability of 6 months or speech impaired, voice Registered authorizers longer, specific eligibility amplifiers voice output work in hospitals, criteria which apply to devices, voice prostheses, home care agencies or each device category writing aids private practice,

Hearing aids: Bone anchored 25% client copayment hearing aid, cochlear implant processors, hearing aids, personal FM systems, TTY

Orthotic devices: Custom standing frames, custom-made braces

Prosthetic devices: Body-powered leg and arm prostheses, electric and myoelectric arm prostheses

Visual aids: Braillers, computer hardware and specialized software, enlarging optical systems (CCTVs), magnifiers, telescopes, binoculars, optical character recognition, specialized glasses, specialized lenses/contact lenses, specialized peripherals (e.g. Braille embossers, refreshable Braille displays), spectacle-mounted low vision and field enhancement aids, standard orientation and mobility canes, audio book playback machines

TABLE 5-1

P A R T II Service Delivery in Assistive Technologies 149

Canadian Public Funding Sources by Province or Territory—cont’d

Province/ Territory and Relevant Special Conditions Departments Assistive Devices Funded or Program Features Eligibility Web Links

Wheelchairs, positioning and ambulation aids: Manual wheelchairs, power wheelchairs, electric scooters, power add-on devices for manual wheelchairs, positioning devices (cushions, back and head supports, etc.), dynamic positioning devices (power tilt and recline), forearm crutches, wheeled walkers, specialized pediatric walkers, strollers, standers

Prince Edward Assistive technologies for An assistive technology Students with special Island: control of the environment, recommendation is made educational needs Department of augmentative communication, collaboratively with parents, Education Student accessing computer programs, school, and department Services Division vision aids, hearing aids, personnel, occupational

aspects of motor and mobility therapy, speech language aids, seating and positioning, pathology; training and accessing sports equipment, technical support for learning self-help and assistive technology is independent living skills, provided by or arranged participation in social for by the Student interactions Services Division

Quebec Walking aids, standing aids, Assessment and device Insured under the Québec http://www.ram.q. locomotor assists and posture distribution services Health Insurance Plan, gouv.qc.ca/en/citoyens/ assists, orthotics and provided in special physical deficiency, assurancemaladie/ prosthetics, crutches, canes, facilities, accredited by medical prescription serv_couv_queb/serv_ walking frames and walkers, the government from a specialist couv_queb.shtml standing aids, manual and powered wheelchairs, wheelbase systems, orthomobiles and children’s strollers, posture assists, hearing devices, visual devices

Saskatchewan: Saskatchewan resident, Saskatchewan Aids valid Health Services card; to Independent referred by an authorized Living Program health care professional;

not be eligible to receive the service from any other government agency such as First Nations and Inuit Health (Health Canada), Workers’ Compensation Board, Saskatchewan Government Insurance or Department of Veterans’ Affairs

Yukon: Manually operated wheelchairs, The physician must apply http://www.hss.gov. Health and Social walking aids, grab bars and for benefits on behalf of yk.ca/ Services support rails, commodes, the patient Education artificial eyes, hearing aids

Other equipment or devices that are medically necessary may be covered

TABLE 5-1

is provided for children through a children’s services ministry or an education ministry. For older adults, the major funding is for seniors in a social services department or, in some jurisdictions, a senior’s ministry. Table 5-1 lists the covered assistive technologies. This list is not complete in all cases because some jurisdictions list devices as examples and consider each request on the basis of medical necessity. Eligibility for funding is also listed in Table 5-1. Assistive technologies are generally funded only for conditions lasting 6 months or longer. In most cases an approved health provider must make a recommendation or generate a prescription for the appropriate assistive technology. Although this is often a medical doctor, many jurisdictions also accept recommen- dations from occupational therapists, physical therapists, or speech-language pathologists, depending on the type of technology being recommended. Some jurisdictions recycle assistive technologies. This only applies to technology that can be cleaned, reconditioned, and upgraded (e.g., with new software in an electronic system) to meet current levels of performance. Some communication devices, wheelchairs, and selected types of aids to daily living are routinely recycled. Customized seating systems, prosthetics and

orthotics, and aids to daily living used for self-care and eating are not generally recycled.

Canadian Federal Sources of Assistive Technology Funding

Federal or national Canadian programs are listed in Table 5-2. These programs may have slightly different forms in each province.

Health Canada—First Nations and Inuit Health: Uninsured Health Benefits. The Federal Department of Health (Health Canada) provides funding to persons of Native Canadian descent for uninsured provincial or territorial items (http://www.hc-sc.gc.ca/fnih-spni/nihb-ssna/benefit- prestation/2004-2005_rpt_e.html). Under the Canada Health Act, provinces and territories are responsible for delivering health care services. First Nations and Inuit people access these insured services through provincial and territorial governments. There are a number of health-related goods and services, including assistive technologies, that are not insured by provinces and territories or other private insurance plans.

150 C H A P T E R 5 Funding Assistive Technology Services and Systems

Canadian Federal Programs That Fund Assistive Technologies

Assistive Devices Special Conditions Program Funded or Program Features Eligibility Web Links

Aging and Seniors Depends on province Benefits related to http://www.phac-aspc.gc.ca/ or territory provincial/territorial seniors-aines/pubs/info_sheets/

programs assistive/index.htm#who Workers’ Devices necessary for One for each province Workplace injuries Varies by province or Compensation return to work and territory including work-related territory Board accidents or diseases

that require medical treatment or time away from work

Health Canada— A variety of mobility Device is listed Canadian resident and http://www.hc- First Nations and devices, aids to daily byprogram; intended one of the following: sc.gc.ca/fnih-spni/nihb- Inuit Health: living items not listed on for use in a home or (1) registered Native ssna/index_e.html Non-Insured Health the benefit list may be other ambulatory care Canadian according to Benefits considered on a settings; not available the Indian Act,

case-by-case basis through any other federal, (2) Inuk recognized with written medical provincial territorial, or by one of the Inuit justification private health or social Land Claim

program; prescribed by organizations, or (3) health professional licensed infant less than 1 year to prescribe; provided of age whose parent is by a recognized provider an eligible recipient

Veterans’ Affairs Aids to daily living, canes, Available devices may Group “A” clients: http://www.vac-acc.gc.ca/ walkers; foot boards, vary by province Pension from Veterans’ clients/sub.cfm?source= overbed tables, raised Affairs Canada health/fallsp/assistdev& toilet seats, bath benches Group “B” clients: CFID=8156146&

Established eligibility CFTOKEN=36150877 for treatment of nonpensioned conditions, established health need, benefits not covered by province

TABLE 5-2

P A R T II Service Delivery in Assistive Technologies 151

Health Canada’s Non-Insured Health Benefits Program supports First Nations people and the Inuit in reaching an overall health status that is comparable to that of other Canadians by providing coverage for a limited range of these goods and services when individuals are not insured elsewhere. Assistive technology devices and services may be funded under this program on a case-by-case basis. A benefit will be considered for coverage when the conditions shown in Table 5-2 are met.

Veterans Independence Program. The Veterans Independence Program is administered by the DVA. As shown in Table 5-2, this program is available to all veterans who require it for their pensioned conditions, wartime pensioners who are seriously or medium disabled, pensioners with multiple health conditions, war veterans with low income, former prisoners of war, and overseas service veterans waiting for a priority access bed. The program covers the provision of wheelchairs, some activities of daily living (ADL), and other self-care equipment.

Opportunities Fund for Persons With Disabilities. The Opportunities Fund for Persons With Disabilities has a primary objective of assisting persons with disabilities to prepare for and obtain employment or self-employment and to develop the skills necessary to maintain that new employment. The program works with employers to assist

them in making their work setting accessible to persons with disabilities and with individuals to prepare them for work or for starting their own businesses. The program also partners with private sector organizations to develop programs that enhance employability for persons with disabilities. Among the benefits listed are expenses related to university tuition, equipment, transportation, and living expenses while in training.

Australian State Government Funding Schemes

The funding programs that are provided through the state governments of Australia have been designed specifically to provide for people with disabilities and include assistive technology in the lists of approved items. The state pro- grams have evolved quite independently in each Australian state or territory and therefore are not uniform. The schemes are administered through various state government depart- ments and are funded from state/territory sources. Although all these programs have similar objectives, there is variation in the level and range of assistance that they provide to peo- ple with disabilities. These programs also vary in their level of means testing. The Australian state funding schemes and their Web links are summarized in Table 5-3. Details of Australian public sources of funding for assistive technology devices and services are shown in Table 5-4.

Australian Funding Programs by State/Territory

Assistive Technology State Funding Program Name Managing Authority Web Site

New South Wales Program of Appliances for New South Wales Department http://www.health.nsw.gov.au/health- Disabled People of Area Health and Community public-affairs/factsheets/pdf/padp.pdf

Services http://www.health.nsw.gov.au/policies/ pd/2005/pdf/PD2005_563.pdf

Victoria Victorian Aids and Department of Human Services http://nps718.dhs.vic.gov.au/ds/disability Equipment Program site.nsf/sectionfour/equipment_service_

providers?opendocument Western Australia Community Aids and Disability Services Commission http://www.dsc.wa.gov.au/2/234/67/

Equipment Program Community_Aids_.pm Queensland Medical Aids Subsidy Queensland Health http://www.health.qld.gov.au/mass/

Scheme default.asp South Australia Independent Living Disability Services South Australia http://www.ilc.asn.au/ilep/

Equipment Program Tasmania Community Equipment Department of Health and http://www.dhhs.tas.gov.au/services/view.

Scheme Human Services php?id=352 Northern Territory Territory Independence and Department of Health and http://www.nt.gov.au/health/docs/reference/

Mobility Scheme Community Services ADS_DisabilityReviewBackgroundPaper_ Feb2006.pdf

Australian Capital Australian Capital Territory Aged Care and Rehabilitation http://health.act.gov.au/c/health?a=sp&pid= Territory Equipment Subsidy Scheme Service 1059610195

http://www.health.act.gov.au/c/health? a=sendfile&ft=p&fid=1059627567&sid= http://www.health.act.gov.au/c/health

TABLE 5-3

Text continued on p. 160

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Program Program of Victorian Community Medical Independent Community Territory Australian Capital Name Appliances Aids and Aids and Aids Subsidy Living Equipment Equipment Independence Territory Equipment

for Disabled Equipment Equipment Scheme (MASS) Program (ILEP) Scheme (CES) and Mobility Subsidy Scheme People (PADP) Program Program (CAEP) Equipment (ACTESS)

(TIME) Scheme Eligibility Resident of Resident of Permanent Permanent Permanent Permanent Resident of the Permanent Assessment New South Wales Victoria, resident of resident of resident of South Tasmanian Northern Territory, resident in the

with a disability holds Western Queensland Australia, people resident having permanent or Australia Capital as defined by Medicare Australia, clients and have a who have a long- or long-term Territory ≥6 the Australian card, long- must have a permanent and permanent indefinite-term duration defined months, permanent Disability term long-term stabilized disabilities, no disability and as likely to last disability that will Services Act disability disability and condition or means test but living at home more than 12 last at least

(medical hold one of the disability and an age limit in the community months, living 12 months, lives practitioner following: hold one of the of 65 years, are or require in or returning permanently in verifies Pensioner following cards: living in or equipment to to the community the community, disability), Concession Centrelink returning to enable discharge (includes clients meets financial require aids Card, Health Pensioner community from hospital or residing in criteria (currently from the list Care Card, Concession Card, accommodation nursing home to individual receiving

Commonwealth Veterans’ Affairs such as client’s live at home in dwellings, group Commonwealth Seniors Card, Pensioner own home or a the community homes, and Centrelink payment), or receives a Concession Card group home and a recipient residents of aged current Carers Payment, (conditions apply), of the following care facilities Commonwealth live in a residential Centrelink Health benefit card assessed as Centrelink* Health situation that is Care Card, entitlements: low-level care), Care Card, not structured to Queensland Health Care Card, hospital in- eligible to receive encourage Government Pensioner patients, being assistance from independent Seniors Card, Concession Card, discharged back other funding living and live Centrelink Health Benefit to the community sources for disability in the community Confirmation of Card, children with are eligible for equipment, such the majority of Concession access to a Health assistance if they as DVA, EACH the time Card, Entitlement Care Card are meet other TIME packages, private

Form (conditions eligible Scheme eligibility health insurance, apply) criteria, in-patients third-party payers

requiring customized for injury/ or specialized compensation equipment, such as a modified wheelchair can be referred to TIME Scheme before discharge to enable equipment to be in place on discharge, require equipment on a permanent or long-term basis

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3 Means Eligibility Victorian If the client is a MASS subsidizes No means test If not a holder of Clients do not have Currently require Testing categories are Aids and not a holder of aids and one of the above to pay to register, applicant to be

defined on the Equipment one of the above equipment for cards, can apply for but you may be receiving basis of income; Program cards, they can eligible people consideration on asked to contribute Commonwealth entitlement subsidizes apply for the grounds of toward the cost Centrelink and priority aids and consideration demonstrated of some items payment such as are defined equipment on the grounds financial need and modifications pension, Carer for each for eligible of financial Allowance, Carer category of people hardship Payment, Disability eligibility Support Pension,

Age Pension Children Children under Children are Children are Different eligibility Age 18 years Children with Age under 16 Children meeting

the age of eligible for eligible applies for downwardfunded access to a health years and family eligibility criteria 16 years are subsidy children aged by ILEP care card are member is in are eligible for eligible less than 16 eligible receipt of 80% of subsidy regardless of years for Centrelink Carer ceiling for parental/carer some aids/ Payment or Carers equipment if the income equipment Allowance or parent(s) receive

depending on approved as Centrelink benefit; the child’s age eligible on basis of otherwise child

financial hardship. receives 20% of Children who are funding in the care of the minister, who meet all other eligibility criteria are eligible for TIME Scheme assistance, irrespective of their foster parents’ income

Individuals Hospital Residents of Current hospital Recipients Clients able to Residents who are People who have People resident Not outpatients, a Common- in-patient, of WorkCover, receive occupying a received in other than Eligible clients with wealth outpatient, or DVA card equipment Commonwealth- compensation hostel-type for the far advanced Government- day patient, holders, from another funded residential or damages to accommodation Program progressive funded current residential funding source, aged care place. provide equipment in a

disease, clients residential recipients of any aged care specifically: On admission to a in respect of Commonwealth- receiving care facility, Commonwealth facility, clients entitled residential aged their disability; funded aged community those Aged Care funding recipients to compensation, care facility people who can care facility; nursing receiving a including resident with a classified DVA Gold Card equipment obtain the recipient of assistance, Community in a high-care high need for holder and previously supplied prescribed item EACH Package; those receiving Aged Care facility (nursing aids and eligible to through CES under another people eligible health insurance Package, home) or equipment or receive equivalent should be returned program: DVA for DVA assistance funds, people who low-care facility those who are item from DVA (discretionary); provides eligible with disability compensable receive aids (hostel); or one of the Rehabilitation hospital clients White and equipment; people clients, and equipment Commonwealth following: Appliances are ineligible while Gold Card in receipt of residents of through other Aged Care hospital inpatients, Program, people inpatients; holders with private health department of government- Packages palliative who require veterans eligible basic aids and insurance for community funded (e.g., EACH), care–eligible assistive for assistance equipment disability services, programs, Flexible Care persons, ostomy technology from the entitlements, equipment,

Continued *Centrelink delivers the social security services to the Australian public.

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facilities for those who are and Community association for discharge Rehabilitation people eligible compensation people with recipients of Aged Care persons, from hospital, Appliances to use other payment for injury; developmental or are entitled Packages and those with people living in Program; motor agencies that people receiving disabilities, to receive similar programs, compensation Commonwealth- vehicle accident provide aids and Workers’ residents in any form of recipients of a claims funded insurance board equipment, Compensation for Common- compensation, compensation Aged Care compensable including the workplace injury wealth people able settlement, and Accommodation clients: clients Commonwealth hostels and to claim the those eligible for (high- and with spinal injury Rehabilitation nursing homes cost of the equipment low-level care), may have access Service, private

aid through through other people who to regional Spinal health funds a private funding programs require the Accounts for provide some aids health (e.g., DVA), equipment assistance with and equipment insurance funding is not specifically and aids, clients who to their members, provider, for vocational only for work, are able to claim people who are people who purposes study, or for aids from high-care have been recreation their private health residents of a discharged care fund, recipients residential aged from a public of Commonwealth care facility hospital or EACH packages extended care center, individuals needing aid or equipment specifically for use at work or in educational settings

Funding Electric Electric Electric Electric Electric Electric Electric Electric Limits wheelchairs wheelchair: wheelchair: wheelchair: wheelchair: wheelchair:$A6000 wheelchair: wheelchair:$A6000- for Electric and $A6000 $A7700 Standard $A5100 $A8500 Communication $A7000 $A9500 Wheelchair: communi- Communi- Wheelchair: Communi- Wheelchair only: aid: $A2000 Communication Communication Communi- cation aids: cations aid: $A11,000 cation aid: $A11,000 aid: $A3000 aid: $A6000 cation aid: must be $A6000 Complex WC: $A3000 Wheelchair Year 2006 greater than $A5000 plus complex

$A800, $A100 Power assist seating Co-contribution. wheelchair communication

Over 16 YO Communication aid: $A4000 means tested. aids:$A7150 Can apply for

No upper Committee overrun limit stated. will also consider

aids that exceed

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the funding limits set by the program provider. Service Providers acting for CAEP remain responsible for device maintenance. The program funds are used for this purpose.

Information Information Web site includes Web site includes Web site Web site informs Web site informs See Web site or Australian Capital Available brochure and brochure, a brochure provides clients of the client of where to telephone: Territory Health to the policy available application detailing detailed prerequisites book an Darwin— Web site Client (see on New South form, and application information, for referral to appointment by 08 8922 7224 Table 5-2 Wales Health’s program process, eligibility, includes the ILEP. Needs telephone or East for Web site) Web site guidelines and equipment application assessment on-line search Arnhem—

available form, eligibility, performed facility for a 08 8987 0416 procedures, before visiting precise location Katherine— application ILEP. Telephone according to the 8973 8778 process, and numbers to client’s town and Barkly— publications locate an suburb. Lists 08 8962 4201

assessor are eligibility criteria Alice provided. and indicates the Springs—

cost to the 8951 6734 consumer.

Application Form obtained Client’s Applicant Inquiries Completing Assessment by Prescriptions Applicant Process from lodgment health care obtains referral should be the ILEP an appropriately for the completes

center. professional from physician directed to application form qualified health issue of an application form Prescription refers to or health care the local MASS (referral section) professional appliance are that can be

required from Victorian Aids professional service center. or by telephoning usually from a completed by downloaded appropriate and Equipment (known as Authorized ILEP where public hospital a prescriber from the health health Program service “referrer”). prescribers application or other using the TIME ACT Web site professional. provider. Referrer sends provide details will be government scheme (see Table 5-2) and

Lodgment Service provider referral to a justification of recorded. service. The health prescription form. provides evidence center staff establishes “specifier” functional On receipt of professional must service provider of eligibility. determines whether applicant requesting an need for the the referral the complete the must develop Physician must means test is within target assessment requested ILEP arranges a application to procedures to sign to indicate eligibility. population; of the aid or any consultation CES for funding process and applicant has a

Equipment if yes, forwards applicant’s specific accessories or for the client with approve permanent, list defines application needs. A specifier modifications. an appropriate prescriptions. stabilized disability. aids and form. It is the is a CAEP- Prescribers health professional. Applicant’s allied equipment responsibility recognized complete all An application health professional categories. of client to health application form (needs) provides report

Lodgment collect all professional. forms and is completed at on function and center processes documentation Specifier will in detail this meeting and information on application required. General recommend explain the forwarded to aids trialed and and orders practitioner the correct applicant’s ILEP. item that meets equipment. certifies diagnosis item of functional/ client’s requirements.

of disability. equipment clinical need

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Victorian Aids and ensure that for the chosen and Equipment funding approval aids and Program do is forthcoming equipment in not fund the from a service the home. This cost of the provider. A service includes assessment provider is an completion of of the client’s organization the needs and who provides manufacturer’s prescription services to a specification of the aids specific disability form (if and equipment. type or range applicable), It is the of types. including any responsibility accessories or of the client to modifications organize and, to detail the when necessary, product to be pay for the supplied to assessment, the applicant. which forms Applications part of the should be application. directed to

Application the local returned to MASS service service provider center. for consideration.

Prescriber Policy guidelines Specialist Select health There are Specialist Search facility on Access to the Prescribers are for Aids and specify assessors professions designated assessors provided Web site will scheme is based designated for Equipment qualifications provide determine the MASS through case locate the closest on assessment each equipment Requirements required for assessments requirement prescribers management health care of need by an category

assessors in in the relevant for aids or for each agency. professional who authorized (occupational relevant categories. equipment. category of can prescribe prescriber. therapist, equipment Applicant pays aid or assistive technology This may be a physiotherapist, categories. costs incurred. equipment physiotherapist, speech

who submit occupational pathologist, an application therapist, specialist registered nurse, to MASS for nurse, or other orthotist, etc.). consideration recommended for subsidy prescriber. funding and who are responsible for application and training. MASS clinical advisers can assist prescribers.

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Co-payment An annual If the item Joint funding Co-payment Co-payment If the cost of the Where the client Client subsidy co-payment of exceeds the conditions conditions is unusual. required item is contributes 50% contribution is $100 is required subsidy cost, include that include MASS in excess of the or more toward on a sliding scale (there are some the service equipment retains ownership ceiling allowed, the cost of the of 10% at lower exclusions and provider that is recyclable of aids and the client will be item, then the cost end through variations to advises the remains the equipment expected to client gains 2.5% at the ceiling this). supplier and property of the when MASS has arrange to meet ownership. cost and above. Co-payments client that a service provider. contributed the deficit. They Any financial Client pays balance or part separate If the applicant more than 50% can consider a contribution (less of subsidy ceiling payments can be invoice has contributed toward the cost range of options than 50%) made to purchase price. negotiated in covering the greater than 50% of the item. including top-up by the client some difference of the device, If the applicant funds from toward the circumstances, must be then the applicant has contributed Disability Services. purchase or repair where applicants issued to the owns the item. more than 50% Equipment of any item does request a more client. If a Maintenance toward the cost provided by not entitle the costly item client has remains of the item as a regional CES client to ownership than would contributed responsibility of co-payment, the outlets remains or part ownership normally be more than 50%, service provider. client can the property of of that item. funded. they can retain If the family/ accept or reject the statewide CES. Equipment no

ownership of applicant has MASS’s offer When no longer longer required or the item and made a significant for ownership. required by the suitable for the be responsible contribution This means client, it must be client must be for the cost of to the initial that the returned. Repair returned to TIME maintenance purchase of an applicant may and maintenance scheme. and repairs, item, they will retain ownership of equipment or transfer not be required of the item and issued through ownership to contribute to be responsible the scheme is and costs of the replacement for the cost of part of the Duty repairs (excluding or updating of maintenance of Care of CES. tires and tubes basic and and repairs or contribute up to for wheelchairs) essential features can transfer $50 in a 12-month to Victorian if item is still ownership of period for this Aids and on list. the item to Duty of Care in Equipment MASS and the addition to the Program. costs of repairs hire/loan fee.

(except large tires and tubes for manual wheel chairs) will be covered by MASS. There are certain items that MASS will only consider subsidizing if the applicant accepts ownership (e.g., voice- output communication devices).

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Prioritization Policy guidelines Priority ratings Priority ratings Category 1: A score of 0 to 15 The three regional Although a person Priority is given in of Funding set priority for include No set to suit service —Enabling is assigned to CES committees may be eligible descending order:

funding on the waiting providers’ specific a Queensland each of the use the following for assistance —Highest priority basis of category: clientele (i.e., public factors below scale to prioritize under the TIME given to equipment eligibility —Clients who specific disability hospital to determine applications for scheme, it does not that will keep category. meet the clinical type or range discharge to the priority assistance for guarantee that a applicant out of

eligibility criteria of types). occur. for a client‘s nonstandard particular aid or hospital of the oxygen —At risk for need for a equipment, item of equipment —Replacement program. imminent particular device: where 1 will be provided. of unsafe or

—Wheelchair hospitalization —Health and represents the This decision is damaged repairs; high because of safety highest priority dependent on the equipment urgency safety or —Independence and 5 represents priority of the —Equipment service category: medical need. and function the lowest priority. application and the and repair

—Aids and —Repairs or —Need for services/ Eligible applications availability of —Ordinary equipment maintenance institutional care are considered in funds. To ensure applications critical to the to existing —Rate of use terms of these clients most in —Applications for safety of client MASS aids and —Area of use priorities and need are assisted, wheelchairs and or injury equipment. —Rapidly placed on a each prescription other high-cost prevention in —Modifications deteriorating waiting list, pending item will be items are weighted daily living or accessories condition the availability of prioritized by a set against activities to MASS aid (diagnostic) funds. of criteria stated established criteria

—Nonavailability for a MASS One point is Applications rating in the policy to decide priority. will lead to a client who is added to the score 1 to 3 are placed document (e.g., deterioration at risk. for each month a on the high priority Category 1—life of the client’s —Replacement client waits. waiting list; 4 and 5 support and safety health or of a MASS aid are placed on the devices). functioning that is unsafe low priority

—Nonavailability for use. waiting list. will lead to Category 2: excess demands —All other on carers in categories. caring for person Low urgency category:

—Length of waiting period

—Clinical factors as indicated by prescribing therapist.

TABLE 5-4

P A

R T

II Service D

elivery in A

ssistive Tech n

o lo

g ies

1 5

9

Equipment Equipment Electronic Communication Communication Electric beds, Mobility aids, Communication Adjustable bed, Covered categories communication aids, cochlear aids, mobility pressure specialized aids, personal communication by the are defined aids, electronic implant speech aids management seating and call alarms, aid, patient hoist Program in the policy voice aids, processor, overlays, positioning pressure care, and sling, manual

guidelines. environmental positioning communication equipment, specialized wheelchair, power Equipment control units, equipment, devices, doorways, communication items, wheelchairs wheelchair, scooter, covered wheelchairs respiratory mobility devices: aids, transfer and scooters modifications to includes and scooters appliances, manual devices seating controls, devices for seating, transfer wheelchairs, etc., pressure mobility and aids, wheeled power scooters, redistributing seating, mobility devices power mattress and seat environmental wheelchairs, cushion control, children’s buggy communication pusher, children’s needs, computer manual tricycle, access, medical children’s manual monitoring, castor cart, sensory children’s power function and castor cart transfer.

Policy guidelines outline criteria for equipment included and excluded.

Local or Local area Department Disability Services Queensland Processing is The three (local) Each district is Applications Centralized health services of Human Commission Health centralized regional ces outlets responsible for processed Processing are responsible Services manages the Department through ILEP. are based at: the provision centrally in the

for PADP, with manages the budget allocated manages the North West–Burnie of TIME scheme ACTESS office at New South budget and to local service overall budget Community Health services in Canberra Hospital, Wales Health allocations providers who in and four local Centre, Jones accordance with Australian Capital responsible to local regional turn manage the MASS service Street their service Territory. for the Victorial Aids distribution of centers deliver North–Launceston agreements. monitoring and Equipment funds among the the client General Hospital There are seven and evaluation Program service disability types services. South–Repatriation local TIME scheme of the area providers. that their Centre, Hobart service providers. health services. Service providers organization serves. These are Darwin

manage Service providers Urban, Darwin program and are, for example, Rural, East Arnhem, determine state-funded Katherine, Barkly, priorities of hospitals, Alice Springs funding Cerebral Palsy Urban, and applications. Association, etc. Alice Springs Rural.

Managing New South Department Disability Services Queensland Disability Services Department of Department of Aged Care and Authority Wales Health of Human Commission Health Health and Health and Rehabilitation

and Area Services Human Services Community Service, Health Services Services Australian Capital

Territory Health

Australian Commonwealth Funded Schemes for the Older Person

The Australian government contributes funding for assistive technology and services for some people with disabilities. The funding is provided through the Department of Health and Ageing (http://www.health.gov.au) and is distributed through schemes that are common to all states and territories throughout Australia. The government-funded schemes are aimed at the frail older person and are generally for the provision of care and accommodation rather than for assistive technology. The eligibility of a person with a disability as distinct from a frail older person to benefit from a funding program is usually an “also” statement grafted on to the definition of a particular scheme.

There are four commonwealth-funded schemes, two that relate to nursing home care and two that relate to funding packages aimed at maintaining frail older people and people with disabilities in the community. Community Aged Care Packages (CACPs) are designed to enable older people who are assessed as eligible for low-level residential (or hostel) care to alternatively remain living in the community. Under the CACP program, a range of services can be provided to the individual, but assistive technology is not included. Extended Aged Care in Home (EACH) packages are similar to CACPs; however, they are targeted at clients who need a high level of care. They were created so that funding can be allocated more efficiently between clients who need high- and low-level care. EACH packages equate to the high-care residential nursing home situation and it is stated in the guidelines that program funds can be used to provide assistive technology.

Australian Department of Veterans’ Affairs—Rehabilitation Appliances Program

The DVA exists to serve members of Australia’s veteran and defense force communities, war widows and widowers, and widows and dependents, through programs of care, compen- sation, commemoration, and defense support services. The Rehabilitation Appliances Program (RAP) is one of the support services offered by the DVA. It is administered by the DVA and provides aids and appliances to eligible members and their dependents of the veteran community to help them maintain their independence as they grow older. This includes war veterans, members of the Australian Defence Force, former members of the Australian Defence Force, cadets, and war veterans from the United Kingdom and other Australian allies, in some cases. The DVA has major offices in all state capitals and 26 Veterans’ Affairs Network offices throughout Australia. Appliances provided under this program must meet a clinical need and must be the simplest, most effective, and least costly equipment that will suffice. Box 5-2 lists typically funded items under the Australian RAP program. DVA funding for appliances is

160 C H A P T E R 5 Funding Assistive Technology Services and Systems

BOX 5-2 Fundable Rehabilitation Appliances Program Equipment/Items

Alarm system/communication appliances/assistive listening devices

Bed adjustable (mechanical/hydraulic/electrical) Communication aids (electronic) Computer (personal) Environmental control unit Hearing aids Low-vision appliances Personal response systems Scooter (electric) Voice prosthesis Wheelchairs (electric and manual)

For further guidelines refer to the RAP Schedule of Equipment. This can be obtained on-line at http://www.dva.gov.au/health/rap/rap.htm.

eligibility tested, and if a person with a disability is eligible for either of the funding schemes the person is generally excluded from using state-based schemes.

Australian Motor Vehicle Compulsory Third Party Personal Injury Insurance

Each state/territory in Australia has a motor vehicle insurance commission designed to provide compensation for people who are injured and become disabled as a result of road accident trauma. Settlements received by people in this situation should be designed with the provision of assistive technology as one of the essential compensatory strategies for the loss of function by the injured person. The insurance commissions or their representatives are listed in Table 5-5, along with the respective Web sites. Australia wide, Motor Vehicle Third Party Personal Injury Insurance is compulsory; it is commonly known as Compulsory Third Party Insurance.

Australian Government Education Departments

In Australia, the delivery of education services is a state government responsibility. Education departments in each state provide some assistance to students who need assistive technology to pursue their educations. The programs have tended to develop in isolation and therefore differ in detail from state to state. However, the programs generally concentrate on providing assistive technology that is essential for the student’s education, thus limiting the availability or use of assistive technologies (such as communication aids) more broadly in the community. It is recommended that those interested in pursuing this avenue of funding for assistive technology seek further information from the particular state’s education department.

The Australian Disability Discrimination Act 1991 includes a document entitled “Disability Standards for Education 2005” (http://www.dest.gov.au/sectors/school_ education/programmes_funding/forms_guidelines/disability_ standards_for_education.htm). This Australian government standard outlines the obligation that educational institutions have to provide equal access to education for a person with a disability. This standard does not directly discuss assistive technology or funding for devices, but it does clearly state the need for the application of both the hard and soft forms of such technologies to ensure access to education for students with disabilities.

PRIVATE SOURCES OF FUNDING

In addition to public funding sources, there are private sources of funding. These vary by country. Examples of U.S. sources are identified in Box 5-1. Private sources of funding in Canada are shown in Table 5-1. Other Australian sources of funding include nongovernment schools, charitable sources (lotteries, service clubs [e.g., Rotary, Lions, Variety]), philanthropic organizations, private health insurance, and worksafe programs. The availability of these programs, the specific coverage, and the eligibility criteria vary across the country.

Self-Funding

Personal sources of funding include out-of-pocket cash paid by the consumer, private trust funds, and loans. Because of the cost of assistive technology equipment and services, paying cash could be a hardship on the consumer. Sometimes this is the only alternative, however. Some individuals have

trust funds set up where money received from a legal settle- ment is kept to provide for the equipment and services they may need, including assistive technologies. Individuals who use personal funds to purchase assistive technology may be eligible for a deduction or credit on their taxes and should consult with a tax accountant.

In the United States and some other countries low-interest loans are also available for the purchase of assistive technology. These programs are a major initiative of the Assistive Technology Act, which sought to broaden the availability of low-interest loan programs throughout the country. In procur- ing a loan, the consumer shares the responsibility of paying for the equipment, which may increase the consumer’s involve- ment in the process (Reeb, 1989). The Easter Seal Society has recently set up a national loan fund to help persons with disabilities purchase assistive technologies. The loan fund was made possible by a U.S. Department of Education grant. Up to 75% of the equipment costs can be financed. The maximal amount that can be financed is $3200. Some manufacturers and vendors also provide low-interest loans. A consumer in need of a loan should check with these sources as well.

Private Health Insurance

Private health insurance is the source of approximately 35% of all health expenditures in the United States (government and direct private payments comprise the other sources) (U.S. Dept. of Commerce, Bureau of the Census, Statistical Abstract of the United States, 2006, Table 118, p. 98). Most often, insurance is an employment fringe benefit, although individuals also can purchase an insurance policy on their own. Although insurance policies may vary considerably, benefits such as durable medical equipment are almost

P A R T II Service Delivery in Assistive Technologies 161

Motor Vehicle Compulsory Third-Party Insurance Funding for Assistive Technologies in Australia

Jurisdiction Program Web Link

Western Australia Insurance Commission of Western Australia http://www.icwa.wa.gov.au/icwa/ic_menu_list.shtml South Australia Motor Accident Commission Allianz Australia is http://www.allianz.com.au/allianz/CICT+SA.html

the sole claims manager acting on behalf of the Motor Accident Commission of South Australia.

Queensland Motor Accident Insurance Commission (MAIC)– http://www.allianz.com.au/allianz/CICT±QLD.html Allianz Australia is the sole claims manager acting on behalf of the MAIC Queensland.

Victoria Transport Accident Commission http://www.tac.vic.gov.au/jsp/content/Navigation Controller.do;jsessionid=MGOLMNDPMBIA?areaID=25

NSW Motor Accidents Authority http://www.maa.nsw.gov.au/index.aspx Northern Territory Motor Accidents (Compensation) Act http://notes.nt.gov.au/dcm/legislat/legislat.nsf/0/960af

9d56ee9b5d969256e5c00095824?OpenDocument Tasmania Motor Accidents Insurance Board http://www.service.tas.gov.au/Search/PhraseSearch.asp?

Task=Applications&DisplayHeading=Motor+vehicle+ insurance

Australian Capital Third Party Insurance–Australian Capital Territory http://www.nrma.com.au/pub/nrma/motor/ctp/act/ Territory index.shtml

TABLE 5-5

always included. Very often, rehabilitation therapies such as occupational therapy, physical therapy, and speech-language pathology services also will be covered. When assisting an individual with insurance, the ATP will have to ensure that the item or service being sought fits within one or more of the covered services of the policy and that no coverage exclusions or limitations apply. This information will be found in the benefits booklet that is provided with the policy, which details the scope of coverage and exclusions as well as co-payments, deductibles, preferred providers, if any, and appeal procedures. As in public health insurance, funding by private health insurance companies is based on a medical diagnosis and justification of medical necessity. Most private forms of health insurance require the use of current procedural terminology (CPT) codes for billing (see section on billing and coding later in this chapter).

Private health insurance is also a potential source for funding assistive technology devices and speech-language pathology and occupational and physical therapy services beyond what is publicly funded in Canada. Private health insurance is often used to “top-up” benefits when funded amounts are inadequate (e.g., too few hours of training for an augmentative communication device) or when there is a co-payment.

OTHER SOURCES OF FUNDING

There are alternative sources for funding that do not fall under the categories of public or private agencies (see Box 5-1). These sources include service clubs, private foundations, and volunteer organizations. There are various community service clubs (e.g., Kiwanis, Rotary Club) that may be a source of funding for a local individual who has no other means of funding. Service clubs are more likely to provide funding if one of their goals is to help certain disability groups or if the consumer is a member of the club or personally knows someone who is a member. Examples are two funds created by the Muscular Dystrophy Association that allow individuals with neurodegenerative diseases such as MD or ALS to receive up to $2000 to facilitate access to a speech-generating device and up to $2000 to facilitate access to a mobility device.

There are foundations related to a specific disability group that directly supply equipment and services to individuals with that particular disability. Other disability-related foun- dations provide partial funding or assist the consumer in obtaining funding. The American Federation for the Blind provides low-interest loans, for example, to individuals who are visually impaired and need to purchase equipment (Matheis et al, 1991). There are also a number of volunteer organizations (e.g., Telephone Pioneers of America) that may contribute by fabricating a custom device. Usually the labor is provided and the consumer pays for the cost of materials.

Similar benefits are provided by the Canadian National Institute for the Blind.

FUNDING PROCESS AND GUIDELINES FOR PROCURING FUNDING

To obtain funding for assistive technology devices services, individuals with disabilities must follow the procedures and guidelines established by each program for which they are eligible and that covers the items being requested. ATPs play a crucial role in this process. Most often it is the ATP who must make the case for funding by conducting assessments, preparing reports, gathering prescriptions and other docu- mentation, and communicating with equipment suppliers and funding program staff. If there is a trial period, the ATP will generally supervise it and report the results to establish the potential benefit of the device. ATPs also are the primary liaison between the client, the supplier, and the funding sources. If funding is denied, ATPs are often called on to coordinate appeals, which may involve representation of the client or soliciting and then working with a professional advocate who will pursue the appeal on the client’s behalf. Although most of these tasks are not compensated, funding has to be pursued, ATPs have to do it, and it has to work for the consumer to receive the services and devices.

A complicating factor is that consumers may be eligible for multiple sources of funding, each of which may have different rules and procedures. This is particularly true because funding and benefits programs have been created to serve very specific purposes, yet health services are able to serve broader goals. Thus, the same services may be covered by multiple programs (e.g., occupational therapy will be covered as a special education–related service and a health benefit within health insurance) or by Medicaid (in the United States). It also is not uncommon for individuals to have multiple sources of health care coverage (e.g., private health insurance and Medicaid or Medicaid and Medicare). Coordinating the benefits of these programs is important to ensure maximum benefit to the consumer.

Over time, the ATP may be called on to seek funding for the same client and for the same item or service multiple times. Funding will be sought to pay for the initial assessment, for purchase of a device, for payment for training and other services; for repairs or modifications to the device; for periodic reassessment of needs; and ultimately for device replacement. Most programs that pay for equipment purchase or rental also will pay for equipment repair and, as necessary, replacement.

Soft technology services such as training are important for many types of assistive technologies, both for the device user and caregivers. Funding for these services, however, is not always covered, even if device purchase is covered. Obviously, the provision of a device without these services can have adverse consequences for the individual. The ATP

162 C H A P T E R 5 Funding Assistive Technology Services and Systems

may be called on to identify alternative sources for these serv- ices, such as training offered by supplier sales representatives.

The several points during the service delivery process at which funding may need to be pursued are shown in Figure 4-2. To the novice ATP, funding programs can appear as a dense or even impenetrable web, but the funding process is navi- gable. Care and attention to detail are required, but this is not different from the general obligations of the ATP in all his or her professional activities.

IDENTIFYING THE FUNDING SOURCE

The various funding sources are described earlier in this chapter and in Chapter 1. This section provides guidelines for navigating the U.S. process of obtaining funding. This process also applies in broad terms to other countries. In general, consumers will know what programs they are eligible for. If they are eligible for Medicaid, Medicare, private insurance, or Tricare, they will possess a wallet card stating their eligibility. (Suppliers may require photocopies of both sides of this card to be submitted along with the other documentation to support a funding request.) Those who are veterans will know they are eligible for DVA services. Children with disabilities are likely to already have been identified and referred to the early intervention or special education systems. The only program where an ATP is likely to be a valuable asset regarding initial program eligibility is vocational rehabilitation. The client’s ability to demonstrate a potential to work may be dependent on access to assistive technology, and it will be the ATP’s evaluation and report that both identifies that need and establishes eligibility for the broader range of vocational rehabilitation services. From this list of potential funding programs, the ATP must begin to coordinate the justification and documentation process. Specific evaluations and reports may be required by each program. Great care must be taken to prepare written reports to ensure that the standard of need for each program or unique program vocabulary is stated. For example, each of the agencies that provide funding for assistive technologies may have a different standard of need. Educational agencies will fund assistive technology that provides a student with access to education. Medicare and Medicaid only fund durable medical equipment that is medically necessary, such as wheelchairs and seat cushions. In state vocational rehabil- itation agencies, there is a standard that the assistive tech- nology must significantly contribute to the individual’s ability to be productive at work for it to be funded. The role of the ATP is to know which programs are likely to fund the particular types of services and devices that are required by an individual consumer. These can then be matched to the benefits provided by the programs for which the consumer is eligible. Assistive technology equipment suppliers are aware of the funding sources that can be used for reimbursement

of their products, and they can be useful sources of information to the ATP and the consumer. ATP reports describing “needs” must be written with care and written with the expectation the reviewer will be looking for vocabulary that is consistent with the reviewer’s program’s purposes.

Dealing with the multiple public or private agencies is a challenge. Procedures for obtaining funding for assistive technologies, levels of funding, and staff familiarity with the scope of and need for assistive technology and related services vary from agency to agency. For example, some funding agencies require that equipment and services be purchased from an approved list of vendors. Other funding agencies require approval for services and equipment before imple- mentation. It is the responsibility of the consumer and the ATP to locate for each agency the regulations that apply to assistive technology and pursue funding on the basis of those regulations. Another important consideration is the principle of “payer of last resort,” which requires a specific sequencing of multiple benefits or funding programs. The Medicaid program is identified by statute as the payer of last resort in relation to other health benefits programs. For this reason, if a consumer has both Medicaid and Medicare or Medicaid and private health insurance, the procedures related to obtaining payment from Medicare or from the private insurance must be followed first before a claim can be submitted to Medicaid. In general, the procedure for sorting the relationship between multiple funding programs is called “coordination of benefits.” Another characteristic of benefits and funding programs, particularly those that provide health benefits, is that they compartmentalize coverage. Specific services will be provided, such as durable medical equipment, occupational therapy, physical therapy, or speech-language pathology. However, not all these services may be covered. Thus, a program may pay for an item of durable medical equipment but not cover the assessment to establish need for the item or training in its use. These limitations force the ATP to be alert for alternative sources of funding so that all the person’s needs can be met.

As a practical matter, an ATP may not only be interacting with multiple funding programs for the same item or service if a person has dual eligibility and both programs cover the service but also may be working to secure multiple items or services for the client at the same time. The following case study provides an example of a person with multiple funding programs and multiple needs.

To simplify the process of obtaining funding, it is recom- mended that a funding strategy be developed for each consumer. Beukleman and Mirenda (2005) identify five steps in developing such a strategy:

1. Survey the funding resources that are available to the individual.

2. Identify various funding sources for the various activities of an intervention (i.e.,assessment,equipment,and training).

P A R T II Service Delivery in Assistive Technologies 163

The use of a personal funding worksheet such as the one shown in Box 5-3 is helpful.

3. Prepare a funding plan with the consumer and the family members.

4. Assign responsibility to specific individuals for pur- suing funding for each aspect of the intervention.

5. Prepare necessary documentation for the funding request. Be sure to make all requests in writing so that a written record is available if an appeal is necessary.

Keeping current on funding information is time consuming but absolutely essential for the ATP. Every state has a technology assistance project (see Chapter 1) that disseminates information on funding resources and strate- gies. For contact information, refer to the Rehabilitation Engineering and Assistive Technology Society of North America Technical Assistance Project Web site (www.resna.org). Assistive Technology: A Funding Workbook (Morris and Golinker, 1991) also provides information on funding resources and strategies. The independent living centers found in each state are another source of funding information and advocacy. Networking with other assistive technology professionals at conferences, by listservs, and over the phone are other invaluable resources.

JUSTIFYING FUNDING FOR ASSISTIVE TECHNOLOGY SERVICES AND DEVICES

Third-party payers require adequate documentation and proof of need before they will approve funding for assistive technology services or equipment. The essential question funding sources want answered is how this technology will improve the individual’s functioning. Whether it is a med- ical, vocational, or educational need, there are essential com- ponents that should be included in any written justification. Golinker and Mistrett (1997) identify components to address when justifying a medical need for a device, but these elements can apply to other justifications as well. These components are summarized as follows:

1. A description of the specific functional limitation that the device and service addresses

2. A detailed description of the device, including fea- tures, accessories, and customization

3. A specific description of the effect of the device or service (e.g., how it will alleviate or ameliorate the functional limitation)

4. A description of the evaluation process, how the rec- ommendation was arrived at, and what other alterna- tives were considered

5. An explanation of why the device being recommended is the least costly equally therapeutically effective solution

6. A description of the expertise of the ATP (or interdis- ciplinary team) recommending the services or equip- ment, including general professional experience and specific experience in assistive technology services

A specific criterion for funding under Medicare, Medicaid, and private health insurance is medical necessity. This requires that the justification include “identification of a medical diagnosis, or condition, that is specifically coupled to the functional impairment being addressed by the device” (Golinker and Mistrett, 1997, p 217). A physician’s prescription is required for devices that are medically necessary. Appendix 5-1A provides an example of a form to use to justify funding for augmentative communication devices and Appendix 5-1B shows an example of a justification form for seating and wheeled mobility systems.

When funding is being pursued through a vocational rehabilitation agency, it is important that the written justifi- cation specify how the device will enhance the individual’s ability to function in a work setting. For assistive technology services and equipment to be considered, they need to be part of the consumer’s IPE. Similarly, when funding is being pursued through special education, the justification needs to address how the equipment will give the child access to a free and appropriate education in the “least restrictive envi- ronment.” All assistive technology services and equipment must address goals written in the child’s IFSP for children from birth to 2 years old or in the IEP for children aged

164 C H A P T E R 5 Funding Assistive Technology Services and Systems

CASE STUDY

FUNDING FOR MIRANDA

Miranda is 14 years old and a freshman in high school. She has cerebral palsy and uses a wheelchair for mobility. She is also nonverbal. Her teacher referred her to the assistive technology center for an augmentative com- munication evaluation. During the needs assessment, it was discovered that Miranda was also in need of a new seating and mobility system. Her mother also expressed a desire for Miranda to be more independent at home and to be able to turn the TV and her stereo system off and on. Miranda has a range of assistive technology needs, and it became apparent to the ATP that funding for Miranda was going to have to come from multiple sources. Given the information that was shared during the needs assessment, the ATP completed a personal funding worksheet for Miranda. The ATP will seek funding from the state Medicaid system for the seating and mobility system, from the school system for an augmen- tative communication device, and from Miranda’s personal resources for an electronic aid to daily living (EADL) to turn her TV, stereo, and appliances off and on. Her father is also involved in the local Rotary Club and that may be another source of funding for the EADL.

3 to 21 years. For children in school, an additional comment is appropriate. Many health services also are school-related services. Typically, schools provide these services. If a child needs more health services than a school offers, health serv- ices programs such as Medicaid or insurance will be sought as a supplemental benefit. For Medicaid-eligible children, Medicaid will often pay the school for its provision of certain related services that also are covered by Medicaid, such as audiology, occupational therapy, physical therapy, speech- language pathology, and nursing services.

It is likely that the staff person reading the funding justi- fication has never met the consumer and may not have had any experience with a person with a disability or with assistive technology. It is important that the justification be easily understood and that it clearly depict who this person is, what the needs are, and how the system can help. It may be helpful to include a picture or videotape of the consumer with the system being recommended.

APPEALING THE FUNDING DENIAL

At any point in the funding process, a denial for funding may be received. When requests for funding have been

denied, it helps to be persistent and to submit an appeal for the denial. It is through this persistence that funding sources may eventually include assistive technologies as a regular part of the support they provide.

Every funding agency has an appeals process whereby the client, ATP, family member, or a professional advocate can appeal a funding denial. The first step taken is to deter- mine the procedure for an appeal and the time limitations related to appeals. The next step is to find out why the request was denied. Almost all funding programs will provide an explanation to the client in writing. By knowing the reason for denial, all persons working to help the client can develop an appeal plan. It will be based on a comparison of the denial reason to the facts, to the scope of benefits offered by the program, including program definitions and guidance, and wherever possible, to a comparison of the funding program’s past actions when the same item or service was sought. In short, an appeal plan allows for the development of a specific statement of why the denial is wrong and why it should be reversed. It also will allow for identification of any missing information or clarifying statements to supplement what already has been submitted. Implementation of the plan will be an appeal that specifically addresses the denial reason and thus decreases the likelihood of the appeal being denied as well.

P A R T II Service Delivery in Assistive Technologies 165

Client: __________________________________________________________________________________________________________________ Type of intervention (e.g., augmentative and alternative communication devices, mobility): _______________________________________

Personal Funding Worksheet

Modified from Beukelman DR, Mirenda P: Augmentative and alternative communication, management of severe communication disorders in children and adults, Baltimore, 2005, Paul H Brookes.

Assessment/ Follow-up and Funding Source Recommendations Equipment Purchase Training Follow-along

Medicare

Medicaid

Children’s Medical Services

Developmental services

Tricare

School

Vocational rehabilitation

PASS

VA

Self-funding

Private health insurance

Workers’ Compensation

Community organizations

Other

BOX 5-3

Sometimes a request is denied because a piece of informa- tion was inadvertently omitted, such as a billing code, and resubmission of the request with the necessary information is all that is needed. Or, the denial may have been made because the agency believes that the plan or policy does not include such a benefit, or it may be based on the fact that the provider does not think that the request meets the criteria for funding.

Mendelsohn (1996) discusses typical grounds for appeal and the format that appeals may take. The purpose of an appeal is to convince the funding agency that the denial was erroneous and to have the decision reversed. The appeal should be made in writing to the funding source. It should explain why the denial for funding was inappropriate and provide any additional information that may have been omitted in the initial request (Golinker and Mistrett, 1997). During the appeals process it may be necessary to ask for assistance from a skilled advocacy layperson or an attorney.

BILLING AND CODING FOR SERVICES

Preparing the billing form correctly and using the proper codes on billing forms are necessary to ensure payment. Medical payers require that the provider use diagnosis codes and procedure codes when services are billed. Diagnosis codes are used to describe the person’s condition or the medical reason for the services being requested; it is this condition that is the key to establishing medical necessity. The most widely used diagnosis coding system in the United States is The International Statistical Classification of Diseases and Related Health Problems, tenth revision (World Health Organization, 1992).

In the United States procedure codes are used to describe the services that the provider implemented or the equipment delivered and that are being billed. The Health Care Financing Administration (HCFA) Common Procedure Coding System (HCPCS) is the most commonly used procedure coding system. It has three levels: (1) the American Medical Association’s physician’s CPT is referred to as Level I HCPCS, (2) Level II HCPCSs are the HCFA-developed alphanumerical codes, including codes for durable medical equipment, prosthetics, orthotics, and supplies, and (3) Level III HCPCSs are local codes created as needed by Medicare and other carriers (Acquaviva, 1998). Example CPT codes relevant to assistive technology devices and services are shown in Box 5-4.

The CPT codes are a set of five-digit codes that pertain to the medical service or procedure performed by physicians and other service providers. The CPT Editorial Panel of the American Medical Association establishes the CPT codes, which have become the industry standard for reporting, and updates them on an annual basis. There is a physical medicine and rehabilitation section of the CPT codes under which

occupational, physical, and speech therapy can bill for certain procedures that may encompass assistive technology intervention. The codes in this section are defined in 15-minute segments. For example, an occupational therapist who has instructed a consumer with a visual impairment on the use of sensory aids to increase independence in self-care can bill using CPT code 97535 (“Selfcare/Home manage- ment training [e.g., ADLs and compensatory training, meal preparation, safety procedures, and instruction in the use of adaptive equipment direct one-on-one contact by provider, each 15 minutes”). Practitioners may use codes in any sec- tion of the CPT as long as the service is within the scope of practice for the practitioner (Acquaviva, 1998). A new code specific to assistive technology has been drafted and is in the process of getting approved as an addition to the CPT codes.

PAYMENT PRACTICES

The traditional method of payment for health care has been fee for service. Under this method of payment, providers are paid a certain rate per unit of service (American Occupational Therapy Association [AOTA], 1996). As a result of skyrocketing health care costs in the United States, however, payment practices in the health care field have changed significantly over the last decade. Managed care has emerged as a means of controlling health care costs.

166 C H A P T E R 5 Funding Assistive Technology Services and Systems

Example CPT Codes Used for Assistive Technology Devices and Services in the United States

92605: Evaluation for prescription of non-speech-generating augmentative and alternative communication device

92606: Therapeutic service(s) for the use of non-speech- generating-device, including programming and modification

92607: Evaluation and prescription for speech-generating augmentative and alternative communication device, face-to-face with the patient; first hour

92608: Evaluation and prescription for speech-generating aug- mentative and alternative communication device, face- to-face with the patient; each additional 30 minutes

92609: Therapeutic services for the use of speech generating device, including programming and modification

97504: Orthotics fitting and training 97353: Self-care/home management 97535: Self-care, home management training 97542: Wheelchair management and propulsion 97537: Community/work reintegration training 97755: assistive technology assessment 97761: Prosthetic training, upper and/or lower extremity(s) 97762: Checkout for orthotic/prosthetic use, established

patient, each 15 minutes 97760: Orthotic management

BOX 5-4

The term managed care is used to describe “any method of health care delivery designed to reduce unnecessary utilization of services, and provide for cost containment while ensuring that high quality of care or performance is maintained” (Rognehaugh, 1998, p. 134). Managed care plans are now a major part of private health insurance offerings, as well as part of publicly funded insurance programs such as Medicare, Medicaid, Workers’ Compensation programs, and CHAMPUS.

Several measures are used by managed care plans to limit either provider payments or enrollee use of services.The primary cost-cutting mechanism used in managed care is capitation. Negotiating with providers for a prepaid amount gives providers a direct stake in controlling their costs. In this arrangement the managed care organization (MCO) agrees to pay the provider a set amount of money on a per-member basis in exchange for the provider’s assuming responsibility for furnishing all or certain health services to a patient for a specified period of time (AOTA, 1996). The provider takes the risk that the capitation rate will be sufficient to cover all the costs of care for the members. An enrollee in the MCO’s plan is restricted to using providers that have a contractual agreement with the MCO.

Other measures used by MCOs to control costs include precertification or preauthorization, mandatory second opinions, case management, and use of a third-party administrator (AOTA, 1996). For ATPs, the implications of managed care are many. Primarily it makes it difficult or impossible to get paid for services if the ATP does not have a contract with an MCO or is not part of a group that contracts with an MCO. The ATP also should determine whether the provider requires preauthorization or second opinions before carrying out any services with the consumer. Case managers are being used more often, particularly in situations where the individual has had an injury or accident resulting in a long-term disability.

Most case managers in the United States are nurses who may have limited experience with assistive technology. The case manager is a gatekeeper who controls access to the services that are provided to the individual, including assistive technology. One way for ATPs to learn more about case management and conversely to educate case managers about assistive technology is through the Case Management Society of America (CMSA) and its on-line forums, which can be accessed at the CMSA Web site (www.cmsa.org).

Consumers and ATPs need to continually be involved in educating funding sources and advocating for the inclusion of assistive technology equipment and services in agencies’ policies. As discussed in Chapter 4, ATPs need to expand their documentation of the benefits and outcomes of assistive technology. This documentation provides helpful information when advocating for increased allocation of funding by public and private agencies.

SUMMARY

The various sources of funding for assistive technology serv- ices and equipment are described in this chapter. Sources of funding for assistive technology are either public or private and include programs such as Medicare, Medicaid, vocational rehabilitation, education, private health insurance, low- interest loans, and grants. The ATP should be knowledge- able about the different funding sources and the process for successfully obtaining funding. This includes identifying the appropriate funding source for the consumer, writing a funding justification, billing and coding for assistive tech- nology, and appealing denials as needed. Furthermore, it is important that the ATP advocate at the public policy level for increased coverage of assistive technology services and equipment.

P A R T II Service Delivery in Assistive Technologies 167

Study Questions

1. List the major steps in identifying a funding source for a particular assistive technology device or service.

2. What are the major categories of funding for assistive technology devices?

3. What are the major assistive technology funding sources typically available for a child who is in an edu- cational program and needs an augmentative communi- cation device?

4. What are the most likely funding sources for support of assistive technology devices and services for an adult who sustains a head injury at the age of 25 years?

5. Compare funding sources for assistive technologies in the United States, Australia, and Canada. What fea- tures are common and which are different?

6. Describe two distinct funding sources and identify at least one criterion that must be met by the consumer to be eligible for funding of assistive technology services from each source.

7. What are the types of personal funding? 8. What restrictions are typically placed on private insur-

ance funding of assistive technology devices and services? 9. What is the source of the benefits available under

Workers’ Compensation? 10. What are the major challenges in identifying the most

likely funding source for a given situation? 11. Define the term “medical necessity.” 12. When writing a medical justification for a device for a

consumer, what elements should be included?

13. What are CPT codes, and how can they be used in securing funding for assistive technology services and devices?

14. List three types of alternative funding sources for assis- tive technology devices and services.

15. What are the five steps recommended for developing a funding strategy?

16. Describe the two types of billing codes commonly used in health care.

17. What is managed care, and how does it affect assistive technology service delivery?

18. What is meant by the term capitation? What are the implications of capitation for assistive technology service delivery?

19. What are the major steps taken to appeal a funding denial? 20. How can consumers and ATPs work together to inform

funding sources of the needs for assistive technology services and devices?

168 C H A P T E R 5 Funding Assistive Technology Services and Systems

References

Acquaviva J, editor: Effective documentation for occupational ther- apy, ed 2, Bethesda, MD, 1998, American Occupational Therapy Association.

American Occupational Therapy Association Managed Care Project Team: Managed care: an occupational therapy source- book, Bethesda, MD, 1996, The Association.

Beukelman DR, Mirenda P: Augmentative and alternative com- munication, management of severe communication disorders in children and adults, ed 3, Baltimore, 2005, Paul H Brookes.

Burton J: Workers’ compensation, twenty-four-hour coverage, and managed care, Work Comp Mon 9:11-21, 1996.

Golinker L, Mistrett SG: Funding. In Angelo J: Assistive technol- ogy for rehabilitation therapists, Philadelphia, 1997, FA Davis.

Matheis D et al: The buck starts here º a guide to assistive tech- nology funding in Kentucky, Frankfort, KY, 1991, Department of the Blind.

Mendelsohn S: Funding assistive technology. In Galvin JC, Scherer MJ, editors: Evaluating, selecting, and using appro- priate assistive technology, Gaithersburg, MD, 1996, Aspen Publishers.

Morris MW, Golinker LA: Assistive technology: a funding work- book, Arlington, VA, 1991, RESNA Press.

Reeb KG: Assistive financing for assistive devices: loan guarantees for purchase of products by persons with disabilities, Washington, DC, 1989, Electronic Industries Foundation.

Rognehaugh R: The managed care health care dictionary, ed 2, Gaithersburg, MD, 1998, Aspen Publishers.

U.S. Department of Commerce, Bureau of the Census: Statistical abstract of the United States, 2006, Table 118, p. 98.

World Health Organization: The International statistical classi- fication of diseases and related health problems, 10th revision, Geneva, 1992, World Health Organization.

169

Sample Forms for Documenting Consumers’ Equipment Needs

A P P E N D I X 5 - 1

APPENDIX 5-1A

Communication Prosthesis Payment Review Summary

Instruction

1. PATIENT INFORMATION > Name—Patient’s complete name > Address—Patient’s home address > Birthdate—Month/day/year > Health Insurance Number—Appropriate number for

coverage > Medical Diagnosis—Document medical diagnosis

(ICD-9-CM) for the patient > Speech-Language Diagnosis—Document Speech-

Language diagnosis (ASHACS) for patient

2. FACILITY INFORMATION > Facility—Wherre the patient is receiving treatment > Address/Phone Number—Facility address and phone

(with area code) > Physician/Specialty—Physician in charge of this case > Speech-Language Pathologist—SLP working with patient

3. DEVICE INFORMATION > Item Description—General description of device being

recommended > Manufacturer—Maker of the device > Distributor/Dealer—Local source of supply, including

service and training

4. PATIENT’S PHYSICAL STATUS > Check the square that characterizes the patient’s current

physical condition per medical/clinical documentation or personal observation

> Adequate/inadequate rating related to physical patameters only as they apply to the use of the specific communication device

> Nonessential rating indicates status is not related to the use of the device for this patient.

5. PATIENT’S COGNITIVE PREREQUISTES > Check the appropriate square that best describes the

patient’s current status. > If applicable, provide the name of the testing instrument

and the scores obtained

6. SELECTION OF AUGMENTATIVE COMMUNICATION DEVICE a. Current Means—Describe how this patient currently

communicates and why it is not the best method of choice. b. Other Devices—List other devices considered for this

patient and why they would not be applicable. c. Rationale—What characteristics of this device influ-

ence the determination that it was the best choice, e.g., portability, size, symbols, service, or training.

d. Indicators—Has the patient had an opportunity to use the device? How long? Rental? What was observed, e.g., increased initiation of ADLs

7. PROGNOSIS a. Communication Ability—Will the patient’s ability to

communicate basic needs, such as health and safety information, be improved?

b. Independence—Will the patient’s independence increase with the use of the device?

c. Placement—Will the community placement be affected? Example: group home vs. nursing home.

d. Academic Ability—Will the patient’s ability to learn and retain new information change?

e. Vocational Training—Will the patient’s ability to advance in vocational rehabilitation improve?

8. COMMENTS—Give any comments unique to this device or what it will offer for this individual that would help in deter- mining payment. Use space provided on the reverse side of the summary form.

170 C H A P T E R 5 Funding Assistive Technology Services and Systems

Name Address City Birthdate Medical Diagnosis Speech-Language Diagnosis

Communication Prosthesis Payment Review Summary

1. PATIENT INFORMATION

PLEASE HAVE THE SUMMARY SIGNED AND DATED BY THE PHYSICIAN AND THE SPEECH-LANGUAGE PATHOLOGIST.

5. COGNITIVE PREREQUISITES (Check Appropriate Square)

6. SELECTION OF DEVICE a. Patient’s current means of communication:

7. PROGNOSIS a. Communication ability:

Facility Address City Telephone Physician Specialty Speech-Language Pathologist

2. FACILITY INFORMATION

Item Description Manufacturer Distributor/Dealer

a. General medical status

b. Respiratory

c. Hearing

d. Vision

e. Head control

f. Trunk stability

g. Arm movement

h. Ambulation

i. Seating/positioning for use of device

j. Ability to access the device (switches, etc.)

Summary

Physician

3. DEVICE INFORMATION

4. PHYSICAL STATUS PER DOCUMENTATION (Check Appropriate Square)

State Zip

State Zip

Adequate Inadequate Nonessential

(Signature/Date) (Signature/Date)

a. Attempts to communicate with consistent response mode

b. Functional yes/no

c. Understands that communication will cause an action to occur

d. Understands that symbols (i.e., words, pictures, Bliss, sign) stand for verbal communication

e. Prognosis to develop intelligible speech

f. Demonstrates memory retention of verbal instruction

g. Names of standardized tests and scores (if applicable)

Spelling

Reading

Cognition

b. Other devices considered and rationale for elimination:

c. Rationale for selection of specific devices:

d. Indicators for success with recommended devices:

b. Independence within environment:

c. Placement in less restrictive environment:

d. Academic ability:

e. Vocational training/retraining:

Speech-Language Pathologist

1988 Specialized Product/Equipment Council (SPEC)

Present Absent

Guarded AbsentPoor

Present UnknownAbsent

Health Ins. #

P A R T II Service Delivery in Assistive Technologies 171

Communication Prosthesis Payment Review Summary

8. ADDITIONAL COMMENTS

DEVELOPED BY SPECIALIZED PRODUCT/EQUIPMENT

COUNCIL (SPEC) 1988

172 C H A P T E R 5 Funding Assistive Technology Services and Systems

Funding Justification Letter for Seating and Mobility Systems

To whom it may concern:

Observation of seated posture in this equipment shows:

Date:

Attached please find a detailed assessment, medical justification and equipment recommendation for

(First Name) (Last Name)

who was referred to us for

He/she presents as a year old with a diagnosis of

He/she weighs

He/she presently uses

Seat height of:

Frame depth of:

lbs., is inches tall, and requires a wheelchair for

, which is years old.

The problems(s) with this equipment is (are):

Our assessment revealed:

He/she requires a:

Our recommendation is that the following equipment be provided:

We expect the following outcomes

Other family members present:

Frame width of:

inches

inches

inches

1.

2.

3.

4.

Evaluator Name:

Evaluator Title:

Facility:

Physician Name:

Physician Title:

Facility:

RTS Name:

RTS Title:

Company:

Source: www.rehabcentral.com

If you have any additional questions, please feel free to call me at:

APPENDIX 5-1B

P A R T II Service Delivery in Assistive Technologies 173

Justify Mobility/Seating

Mobility system and seating chosen and why:

Environment where equipment will be used:

Drive system for powered w/c:

Small turning radius needed for environmental access?

Narrow width needed for environmental access?

Mobility system:

Available adjustment/growth:

Further growth achieved by:

Mobility Base

Lighter weight required:

Seat height specified for:

Variable wheel placement required for:

Angle adjustable back:

Home

Community

Other:

Frame depth:

Frame width:

Other:

Other:

inches

inches

Seating depth:

Seating width:

inches

inches

Manual

Power

Mfg Model Size

Full time Part time School/Work

Institution

Full time Part time

Full time

Yes

Yes

No

No

Part time

Folds side/side

Full time Part time

Purchase of frame parts

To allow self-propulsion

User weight greater than 250 lbs.

Overactive user

Multiple power seat functions

Other:

Other:

Increased community access

Foot propulsion

Other:

1-arm drive access

Other:

Other:

Postural control

Head positioning

Rest periods

Control of spasticity

Manual

Accommodation of limited ROM

Changing angle in space for assistance with postural stability

Improved hand access to wheels Improved stability

Stability (amputee placement)

Transfers Accomodation of leg length Table/desk access

Adjustment Replacement of seating

To allow lifting

Broken frame and/or components on previous chairs

Family preference

Extreme tone problems

Breaks apart

Doesn’t fold at all Has quick-release axles

Back folds down onto seat only

Heavy duty required for:

Portability required for:

degrees

Required for:

Reclining back:

Pressure relief

Repositioning

Accommodation of limited ROM

Transfers

Relief from gravity

Clothing or diaper changes, catheterization

degrees

Required for:

Power

174 C H A P T E R 5 Funding Assistive Technology Services and Systems

Backward tilt:

Foreward tilt:

Foot/leg support:

Manufacturer:

Facilitation of postural control

Manual

Repositioning

Head positioning

Relief from gravity

Management of spasticity

Rest periods

Pressure relief

Transfers

Control of lower extremity edema

Required for:

Other:

Head control

Fixed

Swing-away

Full length

Improved wheel access

Upper extremity support

Flip back/locking

Removable

Adj. height

Special height

Elevating (Manual)

Fixed

Swing under

Reduce swelling

Transfers

Proper knee flexion angle

None

Access for propulsion

Caregiver assist

Clothing changes

Accommodation of ROM

Suppport

Proper leg placement

Articulating

Angle adj. knee

Heavy duty

Angle adj. foot

Lift off

Recessed calf panel

Diapers

Flip-up footplate

Grasp

Decreased pair from road shocks

Use over rough terrain

Reclining

Flip back

Adj. angle

Custom length

Durability

Push-ups/transfers

Support for UE support surface

Fixed height

Desk length

Reinforced

Change of height/angles for variable activities

Swing-away

Depth adj. foot

Rotational hanger bracket(s)

Elevating (Power)

Trunk extension Upper extremity movement/contol Transfers

Other:

degrees

Required for facilitation of:

degrees

Power

Manual Power

Other:

Arm style:

Wheels:

Axle adjustment:

Handrims:

Casters/forks:

Push handles:

Antitippers:

Brake extensions:

Required for:

Durability

Proper foot placement

Comfort

For ease of maintenance (no flats)

Durability

Angle adjustment for postural control

Other:

Seat height adjustment

Decreased spasms from road shocks

Other:

Extended or angle adjustable

Caregiver access

Other:

Other:

Required for:

Required for:

Required for:

AccessRequired for: Other:

SafetyRequired for: Other:

Bag & pouch:

Medicines

Special food Catheters Ostomy suppliesOrthotics

Required to hold:

Semi adj. Fully adj.

P A R T II Service Delivery in Assistive Technologies 175

Swingaway/retractable joystick:

Safety Long distance driving

Allow special placement

Needed joystick style/size

Operation of power seat functions

Compliance with transportation

Required for:

Allow table accessRequired for:

Base chosen accommodates:

Required seating

Switches needed for driving or seat function

ECU capability

Add-on power recline

Computer access Communication device

Add-on power elevating leg rests Add-on power seat elevator

Add-on power tilt

Comfort

Ease of use

Increased stability

Pressure relief

Low maintenance

Accommodation of ROM/asymmetries

Control of posture/alignment

Required for:

Other:

Seat cushion:

Seat support:

Other:

Overall comments on mobility equipment:

Seating and Accessories

Other:

Other:

Accommodation of ROM/asymmetries

Comfort

Improved swallowing/respiration

Pressure relief

Low maintenance

Support

Support

Increased stability

Control of posture/alignment

Ease of use

Required for:

Back cushion:

Back support:

Other:

Other:

Growth and/or angle adjustments

Wheelchair folding Disassembly for cleaning

Required for:

Interfacing seat:

Interfacing back:

Optimal positioning

Support during tilt/recline Improving vision

Safety Placement of switches

Accommodation of ROM Control of posture/alignment

Improved feeding/swallowing/respiration

Required for:

Head rest:

Other:

Other:

Safety

Accomodation of TLSO Added abdominal support

Stability Alignment

Assistance with head position/alignment

Assistance with shoulder control/alignment

Required for:

Anterior chest support:

176 C H A P T E R 5 Funding Assistive Technology Services and Systems

Lateral trunk supports:

Control of spasticity

Swing-away for transfers Contoured for more support

Accommodation of asymmetries/decreased ROM

Support Alignment Safety

Improved head and UE function Control spasticity

Required for:

Lateral hip support:

Removable for transfers

Support

Accommodation of asymmetry/ROM

Alignment

Contoured for more support

Required for:

Other:

Alignment

Lateral knee support:

Removable for transfers

Accommodation of asymmetry/ROM

Control

Required for:

Other:

Control of position

Medial and/or anterior knee support:

Removable/flip down for independence

Accommodation of asymmetry/ROM

Alignment

Required for:

Other:

Control of spasticity

Control of spasticity

Foot positioners:

Alignment Safety Stability

Accommodation of asymmetry/ROM

Control of position

Required for:

Other:

Pelvic belt/bar:

Safety Alignment Independent use

Pad for comfort/protection over bony prominences

Maintainence of pelvic position

Required for:

Other:

Special pull angle to control rotation

UE support surface:

Improves shoulder/head position

Work surface Control of upper extremity positionSupport

Placement of communication aids

Required for:

Other:

Protection of flailing upper extremities

Other:

Safety

Overall comments on seating equipment:

PA R T 3

The Activities: General Purpose Assistive Technologies

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Seating Systems as Extrinsic Enablers for Assistive Technologies

Chapter Out l ine

OVERVIEW OF NEEDS SERVED BY SEATING EVALUATION FOR SEATING Needs Identification Human Factors Physical Skills or Mat Assessment Sensory and Perceptual Skills Cognitive Skills Psychosocial Factors Environmental Considerations Physical Context Social Context Institutional Context Matching Device Characteristics to a Consumer’s Needs and Skills

BIOMECHANICAL PRINCIPLES Kinematics: Study of Motion Kinetics: Forces Types of Forces Stress Pressure Newton’s Laws of Motion Friction Sitting Postures and Center of Pressure

PRINCIPLES OF SEATING FOR POSTURAL CONTROL Guidelines for Postural Control Pelvis and Lower Extremities Trunk Head and Neck Upper Extremities

PRINCIPLES OF SEATING FOR TISSUE INTEGRITY Incidence and Costs of Pressure Ulcers Origins of Pressure Ulcers Other Factors That Contribute to Pressure Ulcer

Development Mobility

Spinal Cord Injury Body Type Nutrition Infection Age Sitting Posture Microclimate at the Seat/Buttock Interface Transfers and Handling Techniques Pressure Measurement

PRINCIPLES OF SEATING FOR COMFORT TECHNOLOGIES FOR SEATING AND POSITIONING MANAGEMENT

Design and Construction of Seating Systems Planar Prefabricated Custom Fabricated Standard Contoured Modules Custom Contoured Prefabricated Adjustable Backs

PROPERTIES OF MATERIALS USED TO CONSTRUCT SEATING SYSTEMS

Classification of Cushion Technologies Cushions Made From Cellular Materials Viscoelastic Foam or Matrix Flexible Matrix Cushions Containing Fluid Alternating Pressure Cushions Hybrid Cushions Cushion Covers

SEATING FOR PRESSURE DISTRIBUTION AND POSTURAL SUPPORT

Technologies to Enhance Sitting Comfort for Wheelchair Users Technologies That Increase Ease of Sitting for the Elderly

SUMMARY

179

C H A P T E R 6

For a user of assistive technologies, a prerequisite to anyinteraction or activity is a physical position that is comfortable and that promotes function. The primary purpose of seating devices is to maximize a person’s ability to function in activities across all performance areas (self-care, work or school, play or leisure); for this reason, they are considered to be general-purpose extrinsic enablers.

The first part of this chapter describes the needs served by seating systems, evaluation of individuals for seating, and biomechanical principles related to seating. The remainder of the chapter provides in-depth information on each of the three categories of seating needs, including related princi- ples and the technologies used for intervention. Seating components are typically interfaced with some type of mobility base. For purposes of this text, however, these two systems are separated. Mobility is viewed as a specific- purpose extrinsic enabler (see Chapter 12).

OVERVIEW OF NEEDS SERVED BY SEATING

Three distinct areas of seating intervention have emerged, each serving a particular consumer need.These three categories

of seating intervention are (1) seating for postural control, (2) seating for tissue integrity, and (3) seating for comfort (Geyer et al, 2003).

The needs of children and adults with cerebral palsy and other neuromuscular disorders have led to the development of seating interventions for postural control and deformity management. These individuals typically have abnormal muscle tone, muscle weakness, primitive reflexes, or uncoor- dinated movements that impair their ability to maintain an upright posture in a wheelchair. Their impaired motor con- trol affects their ability to participate in activities of daily liv- ing, can compromise their general health status, and can result in skeletal deformities.

The principles that guide seating design and selection for individuals with cerebral palsy are also relevant to individu- als with other neurological disorders resulting in impaired motor control, such as cerebral vascular accident and trau- matic brain injury. One commonality across all these groups is the dynamic nature of their seating needs over time. Individuals whose motor control impairment results from trauma usually realize improvements in motor function with recovery. In other situations, individuals lose motor control as a disease progresses. Children grow and develop motor skills. The seating system that is designed for individuals in

180 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

Key Terms

Center of Gravity Center of Pressure Compression Dampening Density Envelopment Equilibrium Fixed Deformity Flexible Deformity Force Frictional Forces

Fulcrum Gravitational Line Linear Line of Application Mobility Pelvic Obliquity Pelvic Rotation Planar Pressure Pressure Ulcer Recovery

Resilience Rotational Scoliosis Shearing Sliding Resistance Stability Stability Zone Stiffness Stress Tension Windswept Hip Deformity

Learning Objectives

On completing this chapter, you will be able to do the following:

1. Identify the potential outcomes of seating for postural control, tissue integrity, and comfort 2. Describe a comprehensive seating assessment 3. Describe key biomechanical principles related to sitting and seating technologies 4. Describe the principles of seating for postural control 5. Describe the factors that contribute to the development of pressure ulcers 6. Discuss pressure mapping systems and the issues related to their use in the clinic 7. Discuss the principles of seating for comfort 8. Discuss the design and construction of seating technologies 9. Describe the different characteristics of seating materials

10. Discuss the different classifications of materials used to construct seats

these groups must be flexible so that it can accommodate their changing needs. The primary population served by the category of seating interventions for pressure management is individuals with spinal cord injury. These individuals can have partial or complete paralysis and reduced or absent sensation below the level of their lesions. As a result, they are suscepti- ble to breakdown of the tissue over bony prominences on weight-bearing surfaces. Individuals with multiple sclerosis, those with muscular dystrophy, the elderly, and others who have limited mobility and therefore a reduced ability to relieve pressure from weight-bearing surfaces also benefit from tech- nologies in this category. Postural management to achieve even pressure distribution is a further need of this group.

The third category of seating addresses the need to improve an individual’s level of physical comfort through pos- tural accommodation. Persons in this category may or may not use a wheelchair on a regular basis and typically have nor- mal or near-normal sensation; however, any prolonged sitting causes discomfort from which they are unable to obtain relief. Therefore they have unique needs and are not completely served by either category described above. Specialized seating can help to alleviate this chronic discomfort and maximize function. Box 6-1 shows some of the potential outcomes of seating intervention for these populations.

EVALUATION FOR SEATING

The process of assessing individuals for the purpose of recommending seating technologies requires a systematic method that includes consideration of many factors. The discussion of design of an assistive technology system in Chapter 2 gave a general framework to guide assessment. The purpose of this section is to provide a framework for evaluating consumers specifically for seating. Figure 6-1 outlines a framework to guide the assistive technology practitioner (ATP) through the decision-making process and ultimate selection of seating and positioning technolo- gies that match the needs and skills of the user.

As with other areas of assistive technology, the process of delivering seating services is a transdisciplinary effort involving the skills of several professionals. Occupational and physical therapists typically provide expertise in neuro- motor function, human development, and knowledge of disabilities. A physician documents the medical status and prognosis of the consumer and the medical justification for the seating system. The physician can also indicate whether surgery or other medical procedures are planned and what

P A R T III The Activities: General Purpose Assistive Technologies 181

BOX 6-1 Potential Outcomes of Proper Seating and Positioning

Facilitation of optimal postural control to enable engagement in functional activities

Provision of an optimal balance between stability and mobility in the seated position

Maintenance of neutral skeletal alignment Prevention of skeletal deformities Maintenance of tissue integrity Maintenance of a position of comfort Decreased fatigue Enhance respiratory and circulatory function Facilitate caregiver activities

Outcomes of Needs Identification

• Identification of contexts and related concerns - setting - caregiver support - physical contexts - accessibility - transportation

• Identification of previously used seating system • Identification and prioritization of goals of consumer, family members, and caregivers

Outcomes of Skills Evaluation

Physical Skills

• Orthopedic factors - range of motion - skeletal deformities - skeletal alignment

• Neuromotor factors - muscle tone - reflex patterns - postural control - voluntary movement

• Respiratory and circulatory factors

Sensory Skills

• Vision • Perception • Tactile sensation

Cognitive/Behavior Skills

• Safety awareness • Motivation

- tolerance for technology - aesthetic and cosmetic preferences - acceptance of disability

Functional Skills

• Transfers • Self-care • Mobility, propulsion • Communication • Bowel and bladder function • Other equipment used

Matching

Technologies for

Pressure Management

Technologies for

Comfort

Technologies for

Postural Control

Figure 6-1 Framework for seating and positioning decision making.

effects these procedures may have on the consumer’s seating. Assistive technology suppliers often provide knowledge of available technologies and their application to meet specific goals. Sometimes a rehabilitation engineer provides this service. In cases where the consumer’s need cannot be met by commercial products, the rehabilitation engineer or seat- ing technician can design and build a custom system.

Needs Identification

Figure 6-1 lists the desired outcomes of the identification of needs. It is important to determine exactly what an individual’s specific needs are regarding seating. From the identified needs, goals to be addressed by the seating intervention are developed. It is the ATP’s responsibility to facilitate the identification and prioritization of these goals. Design of a seating system sometimes involves compromising the various goals. For example, desired biomechanical alignment may not be possible for a person with severe postural deformities when the resulting properly aligned position is too uncom- fortable. Any assessment with the goal of identifying seating needs and recommended technology starts with discussion of the occupations the user wants and needs to complete while using the seating system. A general measure such as the Canadian Occupational Performance Measure (Law et al, 1997) provides a systematic means of discussing key occupations in the area of self-care, productivity, and leisure. There are some measures that are specific to seating and wheeled mobility, including the Functioning Everyday in a Wheelchair measure (Mills et al, 2002). The Wheelchair Outcome Measure (Miller, Mortenson, and Garden, 2006) is a new measure that considers function in self-care, productivity, and leisure specifically from the view of an individual who uses seating and mobility devices.

The level of assistance an individual requires to use the seating system is an important consideration in the assessment. Consideration must be given to whether an individual can transfer to the system and fasten any straps independently when he or she expects to use the seating system independently. The complexity of the system and the ease of access influence the demands placed on an individual providing assistance with a transfer.

Functional skills, including transfers to and from different surfaces (e.g., bed to wheelchair, car to wheelchair), self-care skills (e.g., feeding, dressing), wheelchair mobility, written and verbal communication skills, and bowel and bladder care should be evaluated. Equipment the person will use while in the seating system needs to be taken into consideration. For example, respiratory equipment and augmentative communi- cation devices are frequently mounted on the wheelchair and need to be in a position that is functional for the user.

It is important that the individual’s ability to perform functional activities be evaluated both in the existing system and in a simulation of the proposed system. By observing

the consumer performing functional activities from his or her existing system, the ATP learns two things. First, the ATP can determine the consumer’s level of independence and areas where function is impeded. The ATP can also learn what strategies the individual currently uses to complete functional activities. By using the methods described below, the ATP can then simulate different positions with the consumer. The ATP can have the individual perform func- tional tasks while in these simulated positions. Changing the sitting position will affect the person’s ability to perform certain activities. It is important to select a system that maximizes the person’s function and does not interfere with the use of strategies that have proven to be beneficial. For example, a teenager who uses an abnormal asymmetrical tonic neck reflex to operate a single switch should not be prohibited from doing so unless another movement can be found that accomplishes this task. It will sometimes be necessary to trade an ideal seated posture for a posture that allows the individual to be more functional.

Human Factors

Physical Skills or Mat Assessment. The physical evalu- ation includes assessment of orthopedic factors, postural control, and respiratory and circulatory factors (see Figure 6-1). It is recommended that evaluation of physical skills take place with the person both in a sitting position and supine on a flat surface such as a mat. Orthopedic Factors. Orthopedic evaluation involves meas- urement of joint range of motion and assessment of skeletal deformities and skeletal alignment to determine optimal angles for sitting. Obtaining information regarding limitations in range of motion and deformities is necessary to determine whether the goal of the seating system will be to prevent deformities, correct deformities, or accommodate deformities (Trefler, Hobson, and Taylor, 1993).

Starting with the consumer supine on the mat, mobility of the lumbar spine and pelvis are assessed, followed by range of motion measurements of the hips, knees, ankles, upper extremities, and neck. Joint angle and body measurements as shown in Figure 6-2 should also be made at this time. Alignment of the individual’s head, shoulders, and trunk with the pelvis is determined next. Range of motion and skeletal alignment should also be assessed with the individual in a sitting position to determine how the body parts are affected by gravity. Bergen, Presperin, and Tallman (1990) describe in detail a process for measuring joint angles and assessing skeletal alignment.

It is important to determine whether any skeletal defor- mities present are fixed or flexible. In a fixed deformity, permanent changes have taken place in the bones, muscles, capsular ligaments, or tendons that restrict the normal range of motion of the particular joint. Fixed deformities affect the skeletal alignment of the other joints and typically require a

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seating system that is designed to accommodate the deformity. Often, increased tone and muscle tightness cause persons to assume certain postures, and they may appear to have a deformity. With externally applied resistance (passive stretch) in the opposite direction, however, it is possi- ble to move the joint and reduce the deformity. The person is then considered to have a flexible deformity at that joint. Depending on the situation, the seating system may be designed to correct a flexible deformity. Specific deformities and their effects on sitting posture are described in the section on seating principles for postural control.

Some individuals have had surgery to correct one or more deformities. The ATP should be aware of any surgery the consumer may have undergone and be knowledgeable about the implications it has for seating intervention. In other cases, the team may decide during the evaluation that surgical or orthotic intervention should be considered before seating intervention takes place. If this is the situation, referral to the appropriate medical professional is necessary. Letts (1991) examines surgical interventions related to the seated position. Postural Control. The user’s postural control is a key ele- ment to assess, particularly for children developing motor

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ASIT

DSIT B

E

F

G

H

I

L

K

J

N

M AC

RO SS

HI PS

Figure 6-2 Joint angle and body measurements taken during the evaluation. ASit (R and L), behind hips/popliteal fossa; B (R and L), popliteal fossa/heel; DSIT, knee flexion angle; E, sitting surface/pelvic crest; F, sitting surface/axilla; G, sitting surface/shoulder; H, sitting surface/occiput; I, sitting surface/crown of head; J, sitting surface/hanging

elbow; K, width across trunk; L, depth of trunk; M, width across hips; N, heel/toe. (From Bergen AF, Presperin J, Tallman T: Positioning for function: Wheelchairs and other assistive technologies, Valhalla, NY, 1990, Valhalla Rehabilitation Publications.)

control, individuals recovering motor function after a neurological injury such as traumatic brain injury, or someone losing motor control as a consequence of a progressive illness. Two important aspects should be considered: the individual’s ability to control the posture in a sitting position (i.e., how much support is required to maintain a comfortable sitting position with a reasonable amount of effort) and the response to various positional changes.The most effective way to assess these aspects is with the client seated on a mat.

The ability of an individual to control his or her posture during sitting is determined with the client seated on a mat with the feet supported.The client’s sitting ability is described by the amount of support required to maintain a seated posi- tion. Hands-free sitters are those who do not need to use their hands to support themselves to maintain sitting, whereas hands-dependent sitters do need to use their hands. These individuals could not perform a seated activity using the hands without some type of external support. A dependent sitter does not have sufficient motor control to support him- self or herself in sitting at all. Postural control tends to be less than in those in the other two categories.

Postural control typically develops in a cephalocaudal direction, although recovery of postural control after trau- matic brain injury does not necessarily proceed in this fashion. The amount of external control required to assist an individual to maintain a seated position is an important determination. Kangas (2000) recommends provision of the minimal amount of external support. Support may vary with the activity. Less support may be needed when the individual is engaged in a sedentary activity such as watching television. Alternatively, more support is needed when the individual is using his hands for an activity and the focus of attention is on the activity. The individual should not need to divert attention to the maintenance of posture when engaged in an activity.

Finally, the ATP needs to determine the individual’s response to various postural changes. Primarily, the ATP should assess the effect of changes of pelvic position on the client’s postural control. What happens when the pelvis is positioned in a neutral, anterior-tipped or posterior-tipped position? Similarly, what effect does change of spinal align- ment or lower limb position have on postural control? The client’s response to these position changes will influence the configuration of the seating system and whether any dynamic elements need to be provided. Respiratory and Circulatory Factors. The person’s respiratory status and circulation are other factors addressed during the evaluation. With skeletal deformities, pulmonary and cardiac function can be compromised. It is important to know whether certain positions enhance or limit respiration. Circulation, particularly in the lower limbs, needs to be considered as well. Some individuals may have a condition that predisposes them to circulatory problems; particularly for these consumers, positions that impair circulation should be avoided.

Sensory and Perceptual Skills

Vision and visual perception, as discussed in Chapter 3, con- tribute to a person’s balance and sitting posture, and deficits in these areas need to be considered during the evaluation. The configuration of the seat can affect the user’s line of vision. For example, an individual with poor postural control who is unable to maintain spinal extension with consequent neck flexion may not be able to maintain the head in an

184 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

Jillian is a happy 5-year-old girl with cerebral palsy resulting in severe motor impairment. Jillian is nonverbal and uses a smile or an eye blink to indicate yes. She is very alert and aware of her environment. She will be attending kindergarten in the fall. She does not have a wheelchair and has never been evaluated for a seating system. Her parents carry her from place to place or use an umbrella stroller for her as needed. She receives therapy with a neurodevelopmental treatment approach three times a week. When they made the initial phone referral, Jillian’s parents stated to you that they have put off getting a seating system for Jillian because they did not want her to “look handicapped.” With Jillian soon to be attending school, they have decided it is time to get her a wheelchair and seating system.

Jillian has mixed tone. Her lower extremities, particularly her ankles, have increased tone. The tone in her upper extremities is increased as well. Her trunk and neck are hypotonic. She exhibits a startle reflex and the symmetrical tonic neck reflex. She does not have any apparent orthopedic deformities. She is unable to keep her head up for any length of time unless she is reclined back slightly. Jillian can use a switch with her right hand when her head is held upright. She can also use the touch screen on the computer, but she needs help with sitting. Jillian is dependent for mobility and all other functional activities.

QUESTIONS

1. From the information you have so far, what might be the goals of seating for Jillian?

2. Write a list of interview questions you would ask of her parents and therapists.

3. How would you proceed with a seating evaluation for Jillian?

4. On the basis of the information you have about Jillian at this time, what technological approaches would you consider for her and why? What type of positioning accessories would you consider and why?

5. List potential funding sources for Jillian’s seating system. How would you justify her system to the funding source (refer to Chapter 5)?

CASE STUDY

JILLIAN

upright position if the seat to back angle is set at 90 degrees. The user’s line of vision will be downward in this seating configuration. A person’s awareness of body position (proprioception) in space also influences body posture.

Tactile sensation is another factor to consider. Some individuals may react defensively to the touch of certain textures or positioning components on the body. Other individuals lack tac- tile sensation, which can contribute to skin breakdown. The ATP should determine whether there is any known decrease in sensation, particularly in the buttock area, and whether there is a history of pressure ulcers. The condition of the person’s skin on weight-bearing surfaces (including areas on the trunk that are braced by lateral supports) should be checked for evidence of skin breakdown, circulation, color, smoothness, sensation, and moisture (Tredwell and Roxborough, 1991).

Cognitive Skills

Cognitive skills such as problem solving and motor planning are not as much of an issue in seating as in mobility. However, there are a few areas that require consideration. Individuals with poor safety judgment may not be aware of the need to keep a posi- tioning belt fastened, and special considerations may be neces- sary. When the seating system is complex, understanding the client’s cognitive abilities will aid the decision to teach the client or the caregiver about the proper use of the system. Knowing the individual’s language and communication skills (see Chapter 11) will help determine how the ATP gathers information during the evaluation. For example, if a person relies on an augmenta- tive communication device or on yes/no responses, these modes of communication should be used during the evaluation process. If it is known that the consumer is not reliable in his or her responses, then the ATP should seek assistance from a caregiver in interpreting the consumer’s responses to the seating system.

Psychosocial Factors

The meaning that technology holds for the individual is an important factor to explore with the user, although it is more significant for the mobility component of a seating and mobility system. Many clients prefer technology that does not draw attention to a disability. This preference will be a factor in the selection of a seating system. Esthetics is an important factor in acceptance and rejection of the technology (Pape, Kim, and Weiner, 2002). Behavioral problems, such as an agi- tated person who throws himself against the back of the chair, can also present a safety problem that needs to be addressed. Working together with the consumer and the caregiver to address these concerns is essential.

Environmental Considerations

Physical Context. The seating assessment should deter- mine in which environments the seating system will be used (e.g., home, school, workplace, and vehicle and whether it is

necessary for the system to be used in different environ- ments). Knowledge of where the seating system will be used helps the ATP determine whether the system will be removed and reinstalled in the mobility device or other devices. For instance, an individual who transfers to the car seat when traveling from home to school will remove the seating system when the mobility device is stored in the vehicle and replace it on arrival at the destination. Many seating devices designed for young children are intended to pair with different bases (e.g., the system may be used in a stroller, high chair, or floor sitter).

The ATP should determine the extent to which the seating system will be used outdoors. Temperature is an important factor to consider when designing a seating system. Extreme heat or cold will affect the function of many materials, limiting their ability to meet the goals set for use of the system. A more complete discussion of the effect of temperature on materials used in seating systems follows. Exposure to light sources may affect some materials used to cover a system component, altering its properties and again, affecting the function of the system.

Social Context. The ATP must know who is available to assist the consumer with the use of the system when it is used in multiple settings. This knowledge influences the instruction given to the users of the system and influences considerations with respect to the weight, complexity, and maintenance of the system. Many ATPs who recommend seating products have seen situations where a simple seat cushion is placed backward in a mobility device, causing great discomfort to the user. The risk of misuse is much greater with complex seating systems. Consequently, the ATP must ensure that the user and any caregivers are famil- iar with proper use of the seating system. Adequate instruc- tion is key to preventing misuse of the system.

Individuals who routinely lift and carry a seating system must be able to do so without risk of injury. Materials used to construct seating systems have changed in recent years, in part to decrease the weight. However, some custom-made systems, such as foam in place, which will be discussed below, can be quite heavy. Maintenance of the system is another consideration. Air-filled cushions require careful attention to ensure that they are properly inflated and free of punctures. As mentioned above, the properties of some materials are affected by extremes of temperatures, so whoever is responsible for maintenance of the system must take care to avoid dam- age to it in this manner. In some situations, the system that is most ideal for the client cannot be recommended because of the ability of the caregiver to use and care for it.

Institutional Context. Funding implications are a key institutional consideration. General considerations with respect to funding were described in Chapter 5. The ATP needs to remain current on funding requirements when rec- ommending seating products. Another type of legislation has

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unique implications for seating products: the use of restraints. Certain legal jurisdictions have legislation that regulates the use of restraints with individuals residing in institutional settings. The intent of this legislation is to limit inappropriate use of restraints, such as tying an individual into a chair simply to prevent him or her from moving around, when safety is not an issue. This legislation has implications for the use of straps, pelvic belts, and sub– anterior-superior iliac spine (ASIS) bars that are used in seating systems for positioning and safety reasons. The ATP should be aware of whether these types of legislation affect the ability to incorporate positioning belts, and so forth, in a seating system.

Matching Device Characteristics to a Consumer’s Needs and Skills

The information that has been gathered regarding needs and skills provides a profile of the user. It can then be determined which of the three categories in Figure 6-1 matches the consumer’s profile, which allows identification of potential technologies and evaluation of their effectiveness in meeting the consumer’s needs.

The next step is to actually simulate with the consumer one or more of the alternatives. The ATP can observe the effects of changes in body position and materials by having the consumer try variations of the positioning system. Trial positioning is also helpful for assessing the person’s ability to use control interfaces such as the joystick of a power wheel- chair. Changes in position can be made to see whether there are beneficial or adverse effects on the person’s ability to con- trol a device or perform other functional skills. Simulation makes it easier to document the need for and effectiveness of a particular system so that funding can be obtained. If specific cushions or positioning components are being considered for a consumer, it helps to have him or her try the actual product and determine whether he or she likes it. In some instances it may be desirable for the consumer to take the system home for a trial period, which allows the person to use the system over a longer period and in his or her natural environment.

There are several critical questions that can help the ATP evaluate the effectiveness of the technologies that have been simulated and to select an appropriate seating system for the consumer.These questions, which summarize the needs eval- uation, the skill assessment, and the simulation, are shown in Box 6-2. The primary concern is whether the simulated seat- ing system meets the goals identified during the needs assessment. The ATP should consider the extent to which the system achieves desired goals with respect to positioning, support of function, and comfort. The caregiver’s ability to lift, carry, and maintain the seating system is a further factor to consider. A system that does not meet these goals to the satisfaction of the client of the caregiver will not be used.

BIOMECHANICAL PRINCIPLES

To design and implement seating systems effectively for consumers with disabilities, it is important to understand how the laws of physics govern the actions and effects of the mechanical elements of the postural control system. These principles are embodied in biomechanics, the study of body position and movement. This section presents the major concepts of biomechanics, which are fundamental to an understanding of seating and positioning systems for persons with disabilities.

Kinematics: Study of Motion

When seating systems are designed, the position of the consumer, the position of the seating system components, and their movements should be considered. The term kinematics describes movement. The term displacement is used to define the position of a body in space; a change in displacement results in a new position. For example, in a postural support system, one goal is to bring the trunk to a midline position. This action may require a displacement from the rest position to midline by application of an external lateral trunk support.The rate of change in displacement is called velocity. It is also important to know how fast the velocity is changing (increasing or decreasing); this change is called acceleration. One of the most common accelerations is that of gravity. The term gravity actually refers to the acceleration of an object toward the center of the earth. Acceleration of an object is directly related to the force generated by the object’s movement.

There are two fundamental types of displacement: linear and rotational. When all parts of a body move in the same direction, at the same time, and for the same distance, the movement is linear (Low and Reed, 1996). For example, a person generates translational movement when walking.

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BOX 6-2 Critical Questions for Evaluating Seating Technologies

Does the seating system as simulated meet the consumer’s goals and needs (e.g., postural control, deformity management, pressure relief)?

Does the seating system provide stability and allow for maximal performance in functional activities (e.g., transfers, weight shifts, activities of daily living)?

Is the seating system comfortable for the consumer? Is the seating system durable enough to meet the consumer’s

needs for a reasonable period? Is the seating system sufficiently flexible to meet the consumer’s

changing needs (e.g., change in functional abilities, growth changes)?

Are there resources available to ensure appropriate maintenance of the seating system?

Can the consumer or third-party payer finance the cost of the seating system?

Displacements caused by external positioning components can also be translational. If the direction, distance, and time of the movement occur simultaneously, but the movement is through an angle instead of in a straight line, the movement is called rotational. Rotational movements occur around an axis called the fulcrum. The majority of body movements are rotational, such as hip or elbow flexion and shoulder flexion or extension. Some positioning components cause rotational displacements (e.g., reclining the back of a wheel- chair causes rotation at the pelvis and hip).

Kinetics: Forces

Force is a major element in biomechanics and seating for individuals with disabilities. Force is anything that acts on a body to change its rate of acceleration or alter its momentum (Low and Reed, 1996). It is described by both magnitude and direction (Sprigle, 2000). Forces always occur in equal and opposite action-reaction pairs between bodies, although it is often convenient to think of one body being in a force field. Forces can be applied to the body internally or externally. Internal forces are generated inside the body, such as muscle contractions that cause movement of the joints. Externally applied forces come from outside the body and act on it in some way, such as the forces applied by a support surface and components of a seating system such as lateral supports. The force resulting from the acceleration of gravity is another external and ever-present force that acts on the body and influences its posture and movement (Sprigle, 2000). This force on the body acts along a line called the gravitational line, and its effect is localized around a point in the body called the center of gravity. The force of the earth’s gravitational field tends to pull the body toward the center of the earth and must be accounted for in designing a seating system. The center of gravity changes as posture changes from standing to sitting and in different sitting positions.

Four properties of force, which ultimately determine its result, are magnitude, direction, line of application, and point of application. Magnitude is the amount or size of the force measured in newtons, pounds, or kilograms. Forces are applied in some direction, either pushing or pulling, and are applied along a particular line of application. The force acts at a particular point on the body, called the point of application (Low and Reed, 1996).

Types of Forces. There are three different types of force. Each of these types produces different effects on the body, and it is important to understand these differences when designing seating and positioning systems. Tension forces act in the same line but away from each other (pulling apart), such as the force applied on the antagonist muscle during contraction of the agonist muscle. Compression occurs when forces act toward each other (pushing together), such as the force of the vertebrae on the disks in

the spinal column. Shearing occurs when the forces are parallel to each other (sliding across the surfaces), such as the movement that occurs as the head of the femur moves across the acetabulum during hip movement. Each of these types of forces can also be applied externally to the body, such as the force exerted by a seating surface on the ischial tuberosities (compression), the force exerted by lateral sup- ports to extend the trunk (tension), or the force exerted on the tissues in the buttocks when a seat back is reclined (shearing).

Stress. Stress is the resulting molecular change inside biological (e.g., soft tissue and bone) or nonbiological (e.g., metals, plastics, or foams) materials. Stress is caused by the same three types of forces—tension, compression, or shear—and can result in damage to the biological tissue or other material if it is prolonged. For example, a shear force applied to a foam seat cushion can result in tearing of the foam. This is a change in the molecular structure of the foam caused by an externally applied force. Likewise, a piece of connective tissue that is subjected to severe or prolonged compression loading by sitting (e.g., under the ischial tuberosi- ties) may be damaged by crushing of the tissue.This externally applied force results in compression inside the tissue, causing a change in the structure of the biological material.

Pressure. Every force is applied over a surface area. For example, with a postural support system, the force of each component is applied to an area of the body. It is important to determine the effect of each of these forces, and the concept of pressure is important. Pressure is defined as force per unit area, which means that a force applied over a very small area generates more pressure than the same force applied over a larger area. Imagine a 10-pound cat lying on a surface such as your stomach.The force generated by the cat is applied over the entire surface of its body and the pressure is uniform. Now imagine the same cat standing on your stomach.The force of the cat is the same, but the pressure at each of the cat’s paws is much greater (and it hurts more) because the area of applica- tion (the paw) is much smaller than when the force is distrib- uted over the whole surface area of the cat. This basic concept of distributing pressure by increasing the area of application is applied extensively in seating and positioning systems.

Newton’s Laws of Motion. The English scientist Sir Isaac Newton formulated three laws relating to forces on bodies at rest and in motion. Newton’s first law states that a body at rest tends to remain at rest and that a body in motion in a straight line tends to remain in motion unless external forces act to change either of these states. In other words, a body likes to continue what it is doing, moving or resting. This law defines inertia, which is equal to the force required to accelerate an object. Newton’s second law relates three parameters: the mass of a body, the change in velocity

P A R T III The Activities: General Purpose Assistive Technologies 187

(acceleration), and the forces acting on that body. The force is equal to the mass (in kilograms) multiplied by the accel- eration of the body (Force = Mass × Acceleration), which means that the greater the force, the greater the acceleration, or conversely, the greater the mass for the same force, the smaller the acceleration.The force of gravity is the mass of the object multiplied by the acceleration of gravity. This force is commonly referred to as the weight of an object, and it is the reason that an object weighs less on the moon, because the gravitational acceleration there is less than that on the earth.

Newton’s third law is the one most applicable to seating and positioning systems. This law states that if one body exerts a force on another, there is an equal and opposite force, called a reaction, exerted on the first body by the second (Low and Reed, 1996). This law is applied to seating systems with the assumption that every force exerted by the human body while sitting in a wheelchair or a seating system is balanced by an opposite force exerted by the sitting surface on the person (Sprigle, 2000). The force generated by the body is equal in magnitude and opposite in direction to the force generated by the seating system, which is often referred to as equilibrium. When a body is at rest and all internal and external forces are balanced, the body is in a state of static equilibrium. When forces are balanced around a body during movement, resulting in a constant velocity, it is described as dynamic equilibrium. Both types of equilib- rium are important in seating and positioning systems.

Friction. Throughout this discussion, it has been assumed that ideal circumstances exist. For example, a shear force applied to a body causes it to move across a surface, and ideally it encounters no resistance to movement from that surface. In reality, of course, this is not truebecause fric- tional forces exist between two bodies in contact moving in opposite directions (Sprigle, 2000). Two types of friction are defined: static friction and dynamic friction. Static fric- tion is that force that must be overcome to start a body in motion. Static friction is proportional in magnitude to the perpendicular (compression) force holding the two bodies together. Static friction is independent of the area of contact between the two bodies. Once motion is initiated, the resis- tive force is generally smaller, and it takes less force to keep the bodies moving relative to each other than to start move- ment. Friction during movement is called dynamic friction. Both these frictional forces are affected by surface condi- tions such as moisture, heat, texture, and lubricants, and both are important considerations in the recommendation and design of seating surfaces.

Sitting Posture and Center of Pressure

Stability and mobility are two related dimensions of seated postural control. Stability allows an individual to maintain an upright seated position while mobility allows movement

that enables function; for example, mobility allows the individual to lean forward to reach to shake a friend’s hand. Seating interventions for postural control must achieve an optimal balance between stability and mobility.

Two constructs are important to consider when discussing postural control: center of gravity and center of pressure. The location of the center of gravity is fairly well defined in standing. Its location is described as passing through the mastoid processes of the jaw, a point just in front of the shoulder, a point just behind the center of the hip joints, a point just in front of the center of the knee joints, and approximately 5 to 6 cm in front of the ankle joints (Figure 6-3). In this posture the pelvis is in a neutral position and there is a natural lordosis of the lumbar spine (Zacharkow, 1988). The location in sitting is more difficult to determine, but it is usually considered to be lower, with the buttocks and thighs forming the base of support.The individual must main- tain the center of gravity over the base of support to maintain an upright posture in either sitting or standing. Seating inter- ventions for postural control assist the client to keep the cen- ter of posture within the limits of the base of support.

It is not practical to measure or monitor the center of gravity in the clinic. The center of gravity is defined by three-dimensional coordinates. The center of pressure is described only in the horizontal plane, which makes it a much more clinically useful outcome. Its location in the frontal and lateral planes can be identified and monitored in the clinic by using a pressure mapping system. These systems use various technologies to monitor the pressure between the individual and a support surface (i.e., between the client’s buttocks and thighs and the seat cushion). They are most commonly used to show pressure distribution when pressure-relief cushions are evaluated, so their function will be described in greater detail in that section.

As mentioned above, the aim of postural control in seating intervention is to provide the client with a functional upright position (i.e., provide enough support to enable him or her to retain a seated position but also to enable sufficient move- ment to promote function in sitting). Monitoring of the cen- ter of pressure during quiet and active sitting is one way to evaluate the outcome of specific seating interventions. Discussion of the center of pressure is a relatively recent occurrence in the literature. The ideal location of the center of pressure is midway between the ischial tuberosities. Dunk and Callaghan (2005) found that the location of the center of pressure in the frontal plane varied between men and women. They studied various sitting postural parameters of university students engaged in computer activities while sitting on dif- ferent office chairs. They found that the center of pressure was behind the center of mass of the chair for men and ahead of it for women. This finding has interesting implications for seating intervention, although it has not been explored.

Parkinson, Chaffin, and Reed (2006) describe the stability zone or limit, which they define as the balance limits for a

188 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

person in either sitting or standing. A seat back and laterals or armrests will affect the stability limits in sitting. The authors initially hypothesized that the stability was limited laterally by the ischial tuberosities and posteriorly by the coccyx in the absence of these system features. The thighs provide support when the individual is reaching forward. Age, strength, and range of motion were identified as additional factors that affected the stability zone. They quantified the center of pres- sure during a lateral reaching task with a sample that included both young and older individuals and subjects with a body mass index range from underweight to obese. The greater trochanter, rather than the ischial tuberosities, was found to be more indicative of the stability zone because subjects shifted their weight laterally as they reached. Stability during reach was also affected by age, reach direction (lateral and for- ward reach were greater than rearward), and hip breadth (Parkinson, Chaffin, and Reed, 2006).

The center of pressure is an interesting phenomenon that has been explored recently, primarily in a nonclinical popu- lation. The studies described above suggest that differences exist in parameters related to center of pressure between men and women (Dunk and Callaghan, 2005), body mass,

and age (Parkinson et al, 2006). These studies did not include individuals with disabilities, so the implications of the findings to this group are not clear. Further study is needed to explore the relationship between center of pres- sure and function and the effect of various seating interven- tions on this relationship.

PRINCIPLES OF SEATING FOR POSTURAL CONTROL

Children and adults who have irregular tone, muscle weakness, abnormal reflex patterns, shortening of a muscle group, or skeletal deformity are likely to require external positioning devices to control their posture and prevent deformities. Within this category some individuals have mild impairment and require only minimal support, whereas other individuals have severe physical impairment and require extensive postural support. The components making up a seating system can provide support to the body to improve skeletal alignment, normalize tone, prevent deformities, and enhance movement.

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Figure 6-3 A, Line of gravity in erect upright stand- ing. B, Relaxed unsupported sitting resulting in backward tilt of the pelvis and flattening of the lumbar lordosis. C, Erect sitting with reduction in backward pelvic tilt and increased lordosis. LW, Lever arm. (From Frankel VH, Nordin M: Basic biomechanics of the skeletal system, Philadelphia, 1980, Lea & Febiger.)

Guidelines for Postural Control

The most important principle related to postural control is that proximal stabilization, near the center of the body, facilitates movement and control of the head and the extremities (e.g., function). During normal development, the infant achieves stability in the proximal joints before using the distal limbs for manipulation. For example, before a baby can successfully reach out and grab a toy while sitting, he must have mastered the ability to maintain a balanced sitting posture (Bertenthal and Von Hofsten, 1998; Hadders-Algra, Brogen, and Forssberg, 1998; Hadders- Algra et al, 1999; Savelsbergh and Van der Kamp, 1994). Otherwise the hands must be used to maintain balance, which limits their use for manipulation. Seating for postural control provides external positioning components for the individual who does not have internal mechanisms to con- trol body posture. Tredwell and Roxborough (1991) present a classification scheme (Box 6-3) that is useful in describing the amount of control a person exhibits in sitting. Each category is matched with a brief description of the recommended degree of support provided by the seating system.

When any type of external support is provided, care needs to be taken so that the individual is not excessively positioned. We need to keep in mind that sitting is a dynamic activity. We often associate sitting with relaxation and lack of activity and movement, when in fact many activities are performed while sitting, such as writing, driving, talking on the phone, and typing. Even during quiet sitting an individual frequently shifts weight to maintain comfort. It is not uncommon to see individuals “properly” positioned to the point that they are no longer able to use the motor move- ments they have used in the past to complete functional tasks. The fewest restraints necessary to optimize function should be used (Kangas, 2000).

In this section we present a set of general guidelines for proceeding with the development of a postural seating system for an individual.

Pelvis and Lower Extremities. We have described the important role of the pelvis in relation to the center of gravity and sitting.The pelvis is a key point of control, and its position affects the posture of the rest of the body.Therefore, alignment and stabilization of the pelvis is normally the first area addressed in positioning an individual. A position with the pelvis in neutral or in a slight anterior tilt is desired (Mayall and Desharnais, 1995). The pelvis should be level and in midline.

Research examining the role of pelvic stability in the facilita- tion of function supports the assertion of starting with the pelvis when an appropriate seating system in being determined. Two studies investigated the effect of two methods of pelvic stabi- lization: a regular lap belt, typically using hook and pile fasten- ing versus a rigid pelvic stabilizer (a sub-ASIS bar in one case and the Embrace Pelvic Positioner [Body Tech NW, Mukilteo, Wash.; http: //www.dresch.org /web/BodyTechNW.com/ ] in the second) on function of children with cerebral palsy (Miller Polgar et al, 2000; Rigby et al, 2001). Both these studies com- pared daily function, as perceived by the participants and their families, when using the typical lap belt versus the rigid pelvic stabilizer. Results were comparable in both, with better function found with the rigid pelvic stabilizer. Significant differences were found on the Canadian Occupational Performance Measure (Law et al, 1997) before and after implementation of the rigid pelvic stabilizer.The results of these studies are limited by the small sample size, but the convergence of their findings provides evidence for the practice of controlling the pelvis in seating for postural control.

A position with the hips flexed at approximately 90 degrees is recommended for most individuals (Bergen, Presperin, and Tallman, 1992; Trefler, Hobson, and Taylor, 1993; Tredwell and Roxborough, 1991). This angle of hip flexion helps to inhibit extensor tone and reduces posterior tilt of the pelvis, thus keeping the individual positioned back in the seat. In some instances it is necessary to increase the amount of hip flexion (thus reducing the angle to less than 90 degrees) to further inhibit extensor tone. On the other hand, in some instances 90 degrees of hip flexion is not achiev- able (because of deformity) or is not the most appropriate position. Some individuals are not able to maintain an upright position when placed in a position of 90 degree hip flexion. Similarly, tight hamstrings may prevent achievement of 90 degrees at the knees. The ATP needs to determine the effect of deformities and muscle tone on both function and comfort in the sitting position, during a mat assessment, to determine the most appropriate position of the pelvis, hips, and lower extremities. Asymmetrical postures that may be present in the pelvis and hips include pelvic obliquity, pelvic rotation, pelvic tilt, and windswept hips. These postural asym- metries are often interrelated. They may be flexible postures or fixed bony deformities that restrict the mobility of the pelvis and limit the attainment of the recommended pelvic position.

An individual with a pelvic obliquity has one side of the pelvis higher than the other when viewed in the frontal plane (Figure 6-4, A ). The obliquity is named for the side

190 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

BOX 6-3 Levels of Postural Control in Sitting

THE HANDS-FREE SITTER Can sit for prolonged periods without using the hands for

support Seating system is designed primarily for mobility, to provide a stable base of support, and to be comfortable

THE HANDS-DEPENDENT SITTER One or both hands are used to maintain support while sitting Seating system is designed to provide pelvic or trunk support

to free the person’s hands for functional activities

THE PROPPED SITTER Lacks any ability to support self in sitting Seating system provides total body support

that is lower; for example, with a left pelvic obliquity the left side is lower than the right. This deformity is often accom- panied by pelvic rotation, where one side of the pelvis is forward of the other side (Figure 6-4, B). Windswept hip deformity manifests itself with one hip adducted and the other hip abducted. This deformity has usually been found to be the end stage of a sequence that proceeds as follows: hip subluxation and dislocation, pelvic obliquity, scoliosis, windswept hip deformity. Typically, all these components are present in this deformity. The hip on the high side is typically dislocated, and the opposite hip may or may not be dislocated (Letts, 1991). When fixed deformities such as these are present, the seating system should be designed to accommodate them rather than to attempt to correct them (Mayall and Desharnais, 1995).

Support to the pelvis can be provided under, behind, in front, or from the sides. At the very least, a firm seating surface for the individual to sit on will level and stabilize the pelvis. Individuals with moderate to severe involvement typically need more support for stabilization. This support can be provided by contours around the buttocks and up

into the lumbar area. Alteration of the seat to back angle may be required when the individual has severe extensor tone. During the mat assessment, with the person in sitting, the therapist should move the client through different hip ranges to determine which hip angle achieves the most functional muscle tone. This optimal angle can then be replicated in the seating system, bearing in mind that the actual angle of the hip (femur to acetabulum) will be more acute than the seat to back angle of the seating system. A seat with a preischial block is another option used to control excessive extensor tone (Figure 6-5). With this approach, a depression is made in the cushion to accommodate the pelvis and to stop forward movement. Supports to prevent lateral shifting of the pelvis or external rotation of the hips can be provided either by contouring the seat to provide channels that position the thighs or with some form of lateral support at the pelvic level. To support the pelvis from the front, various types of pelvic positioning belts or knee blocks are used. The placement of the belt is important to effectively maintain pelvic position. Depending on the person’s pelvic mobility, comfort, and positioning needs, the pelvic positioning belt is placed at an angle ranging from 45 to 90 degrees to the seating surface, as shown in Figure 6-6. In most cases, a belt with an angle of pull at 45 degrees sufficiently maintains the pelvis in position. If there is excessive hip extension or a need for anterior pelvic mobility, positioning the belt at a 90-degree angle of pull is more effective. Pelvic positioning belts can be soft and flexible (e.g., webbing or padded vinyl) or rigid when more support is required. A rigid pelvic positioning device, also called a sub-ASIS bar (Figure 6-7), is typically a close-fitting, padded metal bar that is attached to the wheelchair frame or seat insert to position the pelvis below the individual’s ASIS. It is designed to be used in conjunction with a complete seat and back system for individuals who require greater control to maintain the neutral position of the pelvis and to prevent pelvic rotation. Similarly, handling of the client to determine the effect of pressure, or control, around the pelvis (e.g., at the ASIS or posterior-superior iliac spine) will help deter- mine optimal placement of any pelvic stabilizing devices.

P A R T III The Activities: General Purpose Assistive Technologies 191

A B

Figure 6-4 A, Pelvic obliquity viewed in the frontal plane. B, Pelvic rotation. (From Siekman A: The biomechanics of seating: a consumer’s guide, Action Dig March/April:8-9, 1992.)

I.T. CANNOT SLIDE FORWARD

Figure 6-5 Antithrust seat. (From Bergen AF, Presperin J, Tallman T: Positioning for function: wheelchairs and other assistive technologies, Valhalla, NY, 1990, Valhalla Rehabilitation Publications.)

Adequately positioning the lower extremities helps to maintain the pelvic and hip positions. The positions of the legs and feet affect the position of the pelvis and therefore need to be addressed simultaneously. It is recommended that the legs be positioned so that the femurs are neutral with respect to abduction and adduction and rotation and with approximately 90 degrees of knee flexion, although there are some exceptions that will be noted below. Some form of sculpting is frequently used in the seat to keep the femurs in a neutral position and to limit adduction and internal rota- tion (Figure 6-8). A frequently encountered problem in the lower extremities is hamstring tightness, which may or may not result in flexion contractures of the knees. Recall that these muscles are closely related to the position of the pelvis. Attempts to position the individual to stretch these muscles and reduce the flexion contracture only result in posterior pelvic tilt and a sliding forward in the chair into a sacral sitting position. Instead, it is best to accommodate this problem by modifying the seating surface (shortening the seat depth or undercutting the front edge) so that the legs are allowed to flex under the seating surface. This maintains the correct pelvic position. If there is fixed knee extension, the lower leg must be completely supported with pads or troughs that match the range of motion in the knee.

Support for the feet is important for maintaining hip and knee position, for preventing deformities in the ankles, and for distributing pressure. If the feet are left to hang or are positioned too low, pressure increases under the anterior thigh area, which can cut off blood flow. Positioning the feet too high places excess pressure on the ischial tuberosities and the sacrum, which can cause formation of a pressure ulcer. It is recommended that the feet be positioned flat and with 90 degrees of ankle flexion (Mayall and Desharnais, 1995). Support surfaces for the feet can be one or two platforms and in different sizes, depending on the person’s needs. Increasing the thickness of the foot support under the shorter leg serves to accommodate unequal lower leg length. Foot platforms can be angled to accommodate fixed plantar flexion contractures of the ankle. Various strapping systems can be used to main- tain the desired ankle position, including straps over the top of the foot, behind the heel, and enclosing the ankle (Figure 6-9).

Trunk. Once the desired position in the pelvis and lower extremities has been obtained, the trunk is considered. An upright position with the trunk aligned in midline is desirable.

192 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

Lumbar Pad

Acetabular or Hip Joint Motion

Anterior Superior Iliac Spine

Seat Belt

Lap Belt

Figure 6-6 Pelvic positioning belts can be applied at 45 degrees (seat belt) or at 90 degrees (lap belt). (From Church G, Glennen S: The handbook of assistive technology, San Diego, 1992, Singular Publishing Group.)

Figure 6-7 Sub-ASIS bar. (From Margolis SA, Jones RM, Brown BE: The subASIS bar: an effective approach to pelvis stabilization in seated positioning, Proceedings of the RESNA Eighth Annual Conference, pp 45-47, June 1985.)

Figure 6-8 Example of sculpted foam cushion to maintain pelvic and femur alignment. (Courtesy Invacare Corp., www.invacare.ca.)

This position may not be attainable if the individual has fixed deformities. Possible spinal deformities are (1) scoliosis, (2) lordosis, (3) kyphosis, or (4) a combination of these. Scoliosis of the spine occurs when there is lateral curvature or rotation of the vertebral column. Scoliotic curves are fur- ther defined according to the anatomical site in the vertebral column that is involved, that is, cervical, thoracic, or lumbar. Compensatory (or secondary) curves develop as a result of the head’s attempting to maintain its upright position (Figure 6-10, A) (Cailliet, 1975). Figure 6-10, B, shows an uncompensated curve with the spine unbalanced and the head lateral to the center of gravity. Rotation of the vertebrae is also frequently found in scoliosis and can cause greater respiratory difficulty than lateral curving (Cailliet, 1975).

The amount of trunk support required depends on how much control over the trunk that the individual has. As in the pelvis, trunk support can be provided from behind, at the side, or in front. The amount of support provided from behind is related to back height and contouring. The height of the back can be varied, depending on the amount of upper body support needed. Someone who requires minimal sup- port can use a lower backrest height, whereas a higher back- rest is necessary for the individual with a need for greater support. Contouring allows us to accommodate the individ- ual’s body shape and provide optimal support. If the person has a kyphosis, the back needs to be recessed so that he or

she is not pushed forward in the seat. For a lordosis, lumbar support can be added to bring the seat back in contact with the person. In cases where the shoulders are retracted, wedged blocks can be added to the back to position the shoulders forward.

When a person has difficulty maintaining a midline position (side to side) of the trunk, lateral support is provided (Figure 6-11). The positioning of the lateral supports depends on how much control the person has. Lateral supports placed high on the trunk and close to the body provide greater control than those placed lower on the trunk (Mayall and Desharnais, 1995). Because the forces placed on the body by the lateral supports can be great, care should be taken in placement of these components and selection of materials (well padded) to prevent tissue dam- age. If there is scoliosis, the application of force at three positions on the body is one means to attempt to limit the progress of the scoliosis, although there is limited evidence to support or refute this use. This three-point system uses

P A R T III The Activities: General Purpose Assistive Technologies 193

Figure 6-9 Example of an ankle positioning system that attaches to the footplate of a wheelchair. (Courtesy Bodypoint designs, Inc., www.bodypoint.com.)

Figure 6-10 A, Development of compensatory curve in scoliosis. B, Uncompensated scoliotic curve. CG, Center of gravity. (From Cailliet R: Scoliosis: diagnosis and management, Philadelphia, 1975, FA Davis Co.)

the principles of equilibrium of forces to stabilize and align the trunk. As shown in Figure 6-11, one pad is applied under the apex of the curve on the convex side (F3), with two other pads opposing it to provide resistance (F1 and F2). One of these pads is placed up high under the armpit and the other point is on the pelvis (Trefler, Hobson, and Taylor, 1993).

Tilting the seating system back slightly can eliminate some of the effects of gravity for individuals with spinal deformities, low tone, decreased strength in the trunk, or poor head control and can also help the individual maintain a more symmetrical posture. The force of gravity is reduced in the tilt position, making it easier to maintain the trunk in midline and increasing the comfort of the laterals. The positive effects of tilt on trunk position must be evaluated by the limitations this position can place on function. Vision, the ability to eat, use of equipment on a tray, and social engage- ment are just some activities that can be compromised when the wheelchair seat is tilted.

When control is required to prevent forward trunk flexion, anterior supports can be used. This type of support is necessary for individuals who need to be in an upright position for a functional or therapeutic activity but who do not have the ability to maintain this position independently. The most common approaches used are straps, chest panels, and rigid shoulder supports. One simple approach is to use straps that are attached to the seat back below shoulder level, come up over the shoulders, and attach to the seating system near the hips (Figure 6-12, A). The chest restraint must be well maintained because it poses a safety concern if the lower attachment becomes loose, allowing the strap to con- strict around the neck (Trefler, Hobson, and Taylor, 1993). Another approach is a solid chest panel in a butterfly, X, or I shape with straps that attach to the seating system as above (Figure 6-12, B). The final approach is to use rigid shoulder components (Figure 6-12, C) that come over the clavicle and hold the shoulder girdle back against the seating system. These components should be adjustable and well padded to ensure stabilization without excessive pressure.

194 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

Figure 6-11 Three-point system of control for reducing the effects of scoliosis. (From Nwaobi OM: Biomechanics of seating. In Trefler E, editor: Seating for children with cerebral palsy: a resource manual, Memphis, 1984, University of Tennessee.)

A

F

B

A

D

E

C

B C

Figure 6-12 A, An example of a chest strap that attaches to the seat back below shoulder level, comes up over the shoulders, and attaches to the seat- ing system near the hips. (Courtesy Bodypoint Designs, Inc., www.bodypoint. com.) B, Solid chest panel in an X design. (Courtesy Daher Manufacturing, Inc.,

www.daherproducts.com.) C, Rigid shoulder supports. (From Bergen AF, Presperin J, Tallman T: Positioning for function: wheelchairs and other assistive technologies, Valhalla, NY, 1990, Valhalla Rehabilitation Publications.)

Head and Neck. With the pelvis, lower extremities, and trunk positioned, head and neck positions are considered next. The position of the head is important in inhibiting abnormal reflexes and maximizing the visual skills of the individual. In some cases a headrest is necessary only part of the time, for example, when the individual becomes fatigued or during transportation. The most common problems lead- ing to the need for positioning of the head include hyperex- tension of the neck, weak neck musculature, lateral neck flexion, and neck rotation. In addition, support may be required to right the head when the person has been reclined. As in the positioning of other body segments, pos- terior, anterior, or lateral components are used for support. Figure 6-13 shows examples of components for each of these types of support. Posterior support can range from a high backrest (for those requiring minimal support) to headrests of different types. With any posterior head sup- port, it is important to avoid triggering extension or pushing the head forward into flexion. Anterior support is typically provided by headbands, which are used in conjunction with posterior head supports. Elastic materials or pulleys provide

a dynamic type of support. These allow movement of the head within a limited range. Lateral supports can be incor- porated into a headrest or provided as separate components. They can be applied at the temporal area, at the neck, or at the side of the face just in front of the ear.

Upper Extremities. Support of the upper extremities is an essential component of the seating system. A lack of support for the arms can adversely affect head and neck position. Additionally, arms that are left to hang can sustain injury if caught on something or can acquire subluxation of the glenohumeral joint of the shoulder. Using an upper extremity support surface, such as a lap tray, helps with positioning of the head and neck, reduces the likelihood of damage to the arms and shoulder joints, and places the hands in a midline position that facilitates bilateral manual activities. The height of the lap tray depends on the needs of the consumer. Commonly the tray is mounted so that it allows the forearms to rest on it with the elbows bent at a 90-degree angle. For individuals with spasticity, a tray mounted higher will help to reduce upper extremity tone

P A R T III The Activities: General Purpose Assistive Technologies 195

Figure 6-13 Head positioning components include headrest, lateral supports, and headband. One or more of these components are included in

head supports. (Courtesy Whitmyer Biomechanix, Inc.)

(Trefler, Hobson, and Taylor, 1993). Some individuals do not want a lap tray but still require positioning of the upper extremities. For these situations, individual arm troughs (Figure 6-14) mounted to the armrests of the wheelchair are available, which provide channeling and support for the arms.

PRINCIPLES OF SEATING FOR TISSUE INTEGRITY

A second major goal of seating interventions is pressure management. The emphasis in this area is to manage sitting pressure and maintain the skin in a healthy condition so that pressure ulcers are prevented. A pressure ulcer is a lesion that develops as a result of unrelieved pressure to the area and that results in damage to underlying tissue (Bouten et al, 2003). Pressure ulcers usually occur over bony promin- ences, with the sacrum, coccyx, ischial tuberosities, trochanters, external malleoli, and heels being the areas most commonly affected. These lesions have also been referred to as decubitus ulcers, bed sores, pressure sores, and dermal ulcers. Because pressure is the major factor influencing the development of these lesions, it is recommended that the term pressure ulcer be used to describe them (National Pressure Ulcer Advisory Panel, 1992).

Much research has been conducted attempting to determine the various factors that contribute to the development of pressure ulcers and to identify tools and strategies for preventing their occurrence. However, it is difficult to isolate all the variables that affect individuals as they go through their daily lives and to make substantive conclusions for a population as a whole on the basis of this research. Each person must be considered individually, and a comprehensive pro- gram of risk assessment and prevention must be developed to address his or her needs. The ATP needs to be aware of the role of seating, as well as all the other variables, to prevent pressure ulcers.

196 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

CASE STUDY

ALEX

Twenty years ago, at the age of 22 years, Alex sustained a spinal cord injury in a single-car accident. The lesion was at T1-T2, leaving him completely paralyzed below that level. After his initial hospitalization and adjustment to his disability, he returned to college and completed a master’s degree in vocational counseling. He has a successful private practice as a vocational counselor, which has kept him very busy. So busy in fact that he did not pay attention to his skin and ended up with a small pressure sore on his left ischial tuberosity. After weeks of medical treatment and hours spent in bed allowing the ulcer to heal, he is ready to get back to working full time again. His doctor has referred him to the ATP for evaluation for a seating system that will manage his pressure. The physician’s report states that scoliosis is also beginning to develop.

Alex currently has a lightweight manual wheelchair with a sling back and a 2-inch foam cushion with a knit cover placed on top of the sling seat. He is independent with mobility by using his upper extremities. He trans- fers in and out of the wheelchair to all surfaces independently, including to and from his car. He is inde- pendent in all self-care activities. He is married, and his wife is responsible for all home management activities. He does admit that he has gotten into the habit of hooking his left arm behind the wheelchair push handle for stability during certain activities. He did not realize that this could be the cause of some of his problems.

QUESTIONS

1. On the basis of the information given, what might be the goals of seating for Alex?

2. Write a list of questions to ask of Alex during the initial interview.

3. How should the ATP proceed with a seating evaluation for Alex?

4. On the basis of the information given, what techno- logical approaches should be considered and why? What types of positioning accessories should be considered and why?

5. List potential funding sources for Alex’s seating system. How could his system be justified to the funding source (see Chapter 5)?

Figure 6-14 Arm trough. (Courtesy Otto Bock, www.ottobockus.com/ products/r_wheel.htm.)

Incidence and Costs of Pressure Ulcers

Individuals who remain in bed for prolonged periods of time or who use a wheelchair and have limited ability to reposition themselves are at risk for development of pressure ulcers. In particular, individuals with spinal cord injury are at a high risk because they lack sensation and have limited movement below the level of the lesion. It is estimated that approximately

one third of individuals with spinal cord injury will encounter some type of tissue breakdown during their lifetimes (Krause et al, 2001) and that approximately 25% of the health care costs associated with the consequences of a spinal cord injury are related to a pressure ulcer (Krause et al, 2001). Other populations with a high incidence of pressure ulcers include individuals with hemiplegia caused by stroke, multiple sclerosis, cancer, the elderly, and individuals who have had a femoral fracture.

Chen, DeVivo, and Jackson (2005) examined pressure ulcer prevalence in persons with spinal cord injury who were followed up through the National Spinal Cord Injury Database over the past two decades. Their sample included 3361 community-dwelling individuals with spinal cord injury who were followed up by nine centers participating in the Model Spinal Cord Injury Systems project. These nine cen- ters were chosen because they collected continuous data throughout the duration of the study. The authors explored the relationship of risk factors and prevalence of pressure ulcer over time following the injury. Thirty-three percent of the sample had a pressure ulcer on entry to the study. It was found that the risk of pressure ulcer was relatively stable in the first 10 years following the injury. There was also a significant prevalence of recent pressure ulcers, which was not fully explained by other factors. Older subjects (50 years and older) were more likely to have a pressure ulcer. Other significant risk factors included male sex, African-American race, single marital status, education less than high school, and presence of other comorbid medical conditions (Chen, DeVivo, and Jackson, 2005).

In addition to the costs for medical care, there are social costs, which have a greater effect (Krouskop et al, 1983). Krouskop et al (1983) identify these costs as including (1) time lost from work, which affects the person and his or her family, (2) time lost from school, (3) time away from family, which can affect the person’s social development, and (4) loss of personal independence and productivity, which results in decreased self-esteem and self-worth.

Origins of Pressure Ulcers

Many factors contribute to the development of pressure ulcers; these are shown in Figure 6-15. External forces applied to a localized area are considered to be the primary cause. With application of external pressure, the normal flow of blood and oxygen to tissue in that area is reduced. If this situation is sustained, changes occur in the tissue cells, and these changes eventually lead to death of the cells. Individuals who have limited movement and lie in bed or sit in a wheelchair for pro- longed periods generate compression forces that reduce the blood supply to the tissues and make them prone to pressure ulcers. Pressure ulcers are most common over weight-bearing, bony prominences because the force at these sites is greater than at other locations covered by subcutaneous tissue.

The amount of external pressure sufficient to restrict the blood flow enough to cause tissue damage has been a point of discussion over the years. The average blood pressure in capillaries ranges from 12 mm Hg in the venous limb to 32 mm Hg in the arteriolar limb (Landis, 1930). External pressure on the weight-bearing surface that exceeds these pressures produces obstruction of the capillaries. When sitting pressures of subjects on various types of surfaces were measured, it was found that the pressure generated by each surface under the ischial tuberosities greatly exceeded capil- lary blood pressure (Kosiak et al, 1958). A contoured, alter- nating pressure chair was the only surface that provided intermittent reduction (in the down position) of pressure to levels in the range of capillary blood pressure. Because most of the seating surfaces in this study generated pressures that exceeded capillary pressure, investigators were led to ques- tion whether that is the primary cause of pressure ulcer formation or whether other factors are involved.

The duration of pressure is a significant variable in the development of pressure ulcers. Kosiak (1959) determined that there is an inverse relationship between the amount of pressure sustained and the time over which it is applied. In a study involving dogs, Kosiak found that a pressure of 600 mm Hg produced ulceration in approximately 1 hour and a pressure of 150 mm Hg produced ulceration in 12 hours.The results of this study are shown in Figure 6-16, A. Microscopic tissue changes were found after application of as little as 60 mm Hg of pressure over 1 hour. This finding is consistent with the theory that exceeding the capillary pressure deprives the cells of enough important nutrients to cause damage at some level.

Time as a variable in pressure ulcer development is taken into consideration with the broad guidelines developed by Reswick and Rogers (1976). These guidelines, based on

P A R T III The Activities: General Purpose Assistive Technologies 197

Pressure Sore

Formation

External forces compress shear

and friction

Transfers and handling techniques

Microclimate at

seat-buttock interface

Sitting posture

Age

Infection

Nutrition

Mobility

Spinal cord injury

Body type

Figure 6-15 Factors that contribute to pressure ulcer development.

years of clinical experience with individuals who have spinal cord injury, establish allowable amounts of pressure that tissue surrounding bony prominences can endure over certain periods. They recommend that pressures on the ischial tuberosities remain in the range of 30 to 60 mm Hg, as shown in Figure 6-16, B. Tissues that are not susceptible to the inter- nal pressure exerted by bony prominences can tolerate higher skin surface pressures or lower pressures for longer periods.

Up to this point the effects of sustained perpendicular (compression) pressure forces on tissue have been discussed. Parallel (or shear) forces play a significant role in the

formation of pressure ulcers as well. Shear forces are generated when two surfaces move across each other in opposite directions, for example, when an individual slides his hips forward in a wheelchair and assumes a sacral sitting posture. In this position the skin remains in contact with the seat surface and the superficial fascia is interlocked with the skin. The deeper portion of the superficial fascia, however, is mobile and slides forward. The blood vessels in this area are stretched and angulated, which causes occlusion. Resulting tissue damage is at a deeper level and typified by a large area of undermining around the base of the ulcer (Reichel, 1958). Bennett et al (1979) believe that it is the combination of pressure and shear that is so effective in occluding blood flow. They found that, when sufficient shear was present, only half as much pressure was needed to cause occlusion. Unfortunately, because of the difficulty in measuring shear, there is still uncertainty regarding the extent to which shear contributes to the development of pressure ulcers.

Friction, the force between two surfaces at rest or in motion, is another component of shear and the development of pressure ulcers. Friction leads to injury and ulceration of the surface of the skin. A typical friction injury to the skin occurs when it moves across a rough surface such as bedding. Dinsdale (1974) found that the skin’s susceptibility to pressure ulcer development is increased with friction. When pressure alone was applied, 290 mm Hg was required to produce ulceration. With the application of pressure and friction, ulcerations were produced with pressure levels as low as 45 mm Hg. Moisture, heat, or properties of materials such as clothing can increase frictional forces.

Other Factors That Contribute to Pressure Ulcer Development

Some individuals can be exposed to the mechanical forces of pressure and shear without pressure ulcers developing, whereas others have very little tolerance to these mecha- nisms. Although compression and shear forces are typically considered to be the chief causes of pressure ulcers, there are several other factors that contribute to skin breakdown and cause some individuals to be more susceptible than others.

Mobility. Moving to relieve pressure over an area is how the body typically responds to prevent tissue damage. Nondisabled subjects make side-to-side weight oscillations several times per minute while sitting (Tredwell and Roxborough, 1991). Normally, when there is a lack of oxy- gen and chemical irritation, pain signals from the nerve end- ings trigger postural changes and there is little tissue damage. Individuals who lack normal sensation, such as those who have sustained a spinal cord injury, are unable to recognize and respond to these pain signals and are particularly susceptible to development of pressure ulcers (Chen et al, 2005).

198 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

B

A

Figure 6-16 A, Relationship between applied pressure and time. Most points above the curve result in ulceration. (From Kosiak M: Etiology of decubitus ulcers, Arch Phys Med Rehab 42:19-29, 1961.) B, Allowable pressures versus time of application for tissue under bony prominences. (From Reswick JB, Rogers JE: Experience at Rancho Los Amigos Hospital with devices and techniques to prevent pressure sores. In Kenedi RM, Cowden JM, Scales JT, editors: Bedsore biomechanics, Baltimore, 1976, University Park Press.)

Individuals whose ability to reposition themselves or whose activity is limited to bed or chair should be assessed for the risk of pressure ulcer development. There are scales avail- able that determine the magnitude of risk by measuring the degree to which mobility and activity levels are limited. Two commonly used scales that assess these factors are the Norton Scale (Norton, McLaren, and Exton-Smith, 1975) and the Braden Scale (Bergstrom et al, 1987). In addition to mobility, these scales also assess other factors that place a person at risk for development of pressure ulcers, such as incontinence, impaired nutritional status, and altered level of consciousness. Individuals should be assessed with a validated systematic risk assessment tool on admission to acute care and rehabilitation hospitals, nursing homes, home care programs, and other health care facilities and at other periodic intervals. Identified risk factors can be reduced through intervention, and the development of pressure ulcers might be prevented.

Spinal Cord Injury. As discussed above, loss of sensa- tion and limitations in mobility put individuals with spinal cord injury at great risk for development of pressure ulcers. In addition, some researchers speculate that other changes in the body that result from the denervation caused by the spinal cord injury increase a person’s susceptibility to pres- sure ulcers. In a study of normal and paraplegic rats, no dif- ferences were found in their susceptibility to pressure (Kosiak, 1961). Constantian (1980) concludes that there is not adequate objective evidence that individuals with dener- vated tissue are predisposed to the development of pressure ulcers nor that denervated tissue heals more slowly or differ- ently than skin with normal enervation. On the other hand, there is evidence that after spinal cord injury there may be tissue alterations (e.g., loss of collagen, abnormal vascularity, tone changes) and changes in hormonal response to stress that place a person more at risk for development of pressure ulcers and that impair the normal healing process (Patterson et al, 1992; Pfeffer, 1991; Whimster, 1976).

Differences in circulatory tissue perfusion between persons who have a spinal cord injury and those who do not have been documented (Patterson et al, 1992). With externally applied pressures of 32 mm Hg, it was found that the partial pressure of oxygen (an indicator of the perfusion of the tissue) was significantly lower in spinal cord–injured subjects than in subjects without a disability. To evaluate the response of the peripheral circulation to externally applied pressure, Patterson et al (1992) cycled the pressure loads on and off. Although oxygen perfusion was lower during both on and off periods for the persons with spinal cord injuries, it was only during the on period that these differences were statis- tically significant. At higher external pressures (75 mm Hg), the differences in oxygen perfusion for the two groups were not statistically significant. The difference between the two groups at the lower pressure was attributed to a lack of vascular autoregulation in the subjects with spinal cord

injuries (Patterson et al, 1992). Autoregulation requires a minimal difference between internal pressure and external pressures. At 75 mm Hg autoregulation cannot occur because the external pressure is near the arterial pressure. Measurements of blood volume showed significant differences between the two groups at both external pressures. This study indicates that there are tissue perfusion changes in spinal cord injury that significantly impair the response to external pressure loads.

Measurement of these factors that may affect the devel- opment of pressure ulcers is improving but remains difficult, which makes it difficult to specify their particular effects on pressure ulcer development. However, it is likely that there are intrinsic changes in the body as a result of spinal cord injury that cannot be ignored. These changes may result in tissue with different properties and a reduced tolerance to external pressure.

Body Type. The body type of the individual has some effect on pressure distribution. A thin person has less subcu- taneous fat to act as padding, and therefore forces per unit area of the skin are increased. An overweight individual has more padding over which to distribute pressure. However, it may be more difficult for the overweight individual to per- form pressure relief exercises. Caregivers may also have more difficulty moving an overweight individual, which may make shearing and friction forces a greater possibility.

Nutrition. Inadequate nutrition is often associated with weight loss and muscular atrophy, both of which reduce the amount of tissue between the seat surface and the bony promi- nences. Inadequate dietary intake, which results in anemia, decreased protein levels, and vitamin C deficiency are also known to interfere with the normal integrity of the tissue (Berecek, 1981; Breslow, 1991) and have been linked not only to pressure ulcer development but also to delayed healing. An increased intake of protein and calories has been shown to improve the healing rate of pressure ulcers (Breslow, 1991).

Infection. Torrance (1983) identifies three reasons why infection may contribute to pressure ulcer development. First, fever caused by infection increases the metabolic rate, which increases the demand for oxygen, which in turn endangers areas that are ischemic. Second, severe infection can also affect the nutritional balance of the body. Finally, localized bacteria increase the demand on metabolism in a localized area.

Age. As people age, the skin loses some of its elasticity and muscles atrophy, which increases vulnerability to friction or shearing. Vascular and neurological diseases associated with aging (e.g., diabetes, renal disease) affect the circulation and may also increase an individual’s susceptibility to skin breakdown.

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Sitting Posture. Posture and deformity can affect the pressure distribution of the seat/buttock interface and can potentially contribute to skin breakdown. Two specific pos- tures that pose a risk for pressure ulcer formation are pelvic obliquity and sacral sitting. Pelvic obliquity, which was dis- cussed in detail in a previous section, results in increased pressure and shear under the affected lower ischial tuberosity and the posterior aspect of the lower greater trochanter (Hobson, 1989; Zacharkow, 1984, 1988). The loss of lumbar lordosis when sitting is another risk factor. This position occurs as a result of limited hip mobility for flexion or decreased spinal mobility for extension (Zacharkow, 1984). Consequently, a sacral sitting posture is typically assumed, which results in significant amounts of pressure being placed on the sacrococcygeal region.

Microclimate at the Seat/Buttock Interface. The microclimate between the body and the seating surface is a critical factor that is often overlooked. The temperature of the skin and the presence of moisture both affect the formation of pressure ulcers. An increase in skin temperature of 1°C is accompanied by a 10% increase in the metabolic demands of tissue (Fisher et al, 1978; Stewart, Palmieri, and Cochran, 1980). In tissue that already has limited oxygenation as a result of pressure, the potential for breakdown is exacerbated. Moisture, from perspiration or incontinence, also increases the risk of skin breakdown for a number of reasons. Wet skin is weaker than dry skin and therefore more likely to incur damage as a result of compression and friction (Stewart, Palmieri, and Cochran, 1980). Additionally, moisture increases the potential for bacterial growth and infection. Keeping the skin clean and dry is important for these reasons.

The material of the seat cushion and its cover can alter the temperature and the amount of moisture at the seat/ buttock interface. Foam cushions have been found to cause an increase in skin temperature, whereas water-filled cushions reduced skin temperature (Fisher et al, 1978; Stewart, Palmieri, and Cochran, 1980). Excessive moisture can also be a problem that varies with the cushion, its cover, and the user. Gel and water cushions have been found to increase the amount of humidity at the seat/buttock interface by 23% and 20%, respectively (Stewart, Palmieri, and Cochran, 1980). Selecting cushion materials and coverings that reduce temperature and moisture accumulation is discussed later in this chapter.

Transfers and Handling Techniques. Abrasions or ulcerations can be caused by hitting objects or sliding across a surface during transfers. Whether the individual transfers independently or has someone providing assistance, care should be taken to prevent abrasions. The same holds true for mobility in bed. Pulling an individual across the bed sheets can cause abrasions or ulcerations from the friction. Caregivers should be reminded to lift an individual to move

him or her in bed instead of sliding the individual across the bedding.

The development of pressure ulcers is a complex process, and there is still much to be learned about the exact mechanisms involved. Identifying factors that predispose an individual to pressure ulcers will help in developing a com- prehensive pressure ulcer prevention program. A program for preventing pressure ulcers should include (1) a wheelchair and seating prescription for pressure distribution, postural alignment, and stability, (2) a pressure relief program, (3) dietary instruction and adequate nutrition, (4) instruction in proper transferring and lifting techniques, and (5) main- tenance of good personal hygiene and skin care (McDonald, 2001). The development and implementation of the preven- tion program should be considered a continuing team effort involving the consumer, his or her therapists, and medical personnel.

Pressure Measurement

Pressure ulcers result from sustained compression of soft tissues, particularly under bony prominences. The predominant hypotheses concerning the pathogenesis of pressure ulcers include localized tissue ischemia, sustained deformation of the cells, impaired nutritional flow to the cells, reperfusion injury, and inadequate drainage of cellular waste products (Lander Ganz and Gefen, 2004; Stekelenburg et al., 2006). Lander Ganz and Gefen demonstrated that the pressure measured at the deep tissue level was significantly greater than that measured at the surface interface, although they could not predict a specific relationship. The prevalence of pressure ulcers and the resulting costs underscore the need to measure the forces applied to the muscle in an attempt to prevent prolonged exposure to high loads. Many sophisticated pressure measurement systems have been developed, including near infrared tissue spectrophotoscopy, Raman spectrography, and in-dwelling sensors. However, these systems are not feasible in the clinical situation.

In the clinic, pressure mapping systems are the primary means of quantifying pressure. These systems quantify pressure at the buttock/seat interface, allowing a comparison among various cushions. In measuring sitting pressure, it can also be determined whether the individual has any evidence of asymmetry in sitting and what influence changing the configuration of the seating system has on correcting the asymmetry. Many commercial pressure measurement systems are available for commercial and research use. These technologies are constantly improving, but issues remain with consistency of the measurement and lack of agreement around best practices for pressure measurement protocol. The three most common pressure mapping systems are the Force Sensing Array (Vista Medical; www.pressuremapping.com), F-Scan (Tekscan) (www.tekscan.com), and Xsensor (Xsensor

200 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

Technology Corporation, www.xsensor.com). Each of these systems uses a flexible matrix of pressure sensors that provide a map of the distribution of pressure at the interface between the seat cushion or back and the client’s body. These sensors are arranged in a grid pattern on the pressure mat. The number of sensors and their sensitivity varies across the different systems and should be taken into consideration when considering the purchase of a system. They vary in the technology used to measure pressure. These technologies include capacitance sensors that measure the ability to store an electrical charge, piezo-resistive sensors that measure the change in resistance when force is applied, and electrically conductive sensors that measure the change in current flow. Two properties influence the reliability of the pressure measurements: creep and hysteresis. Creep refers to the stability of the pressure reading over time. Hysteresis refers to the change in pressure reading as the device is loaded and unloaded (e.g., as the client sits on the cushion). Each of these systems corrects for these two variables in their software, but these properties still influence the reliability of the measurement systems to varying degrees, which needs to be taken into consideration when these systems are used clinically.

The output from each of these systems is generally similar, although care must be taken when the results of research or measurements obtained by use of the different systems are compared. As will be seen below, these systems differ in their performance. All the systems provide a visual output (Figure 6-17) that allows a quick inspection of the

pressure distribution. The visual output may show pressure distribution with a color display or as peaks and depressions. The actual pressure value for each cell can be displayed as well. Data are captured continuously at varying sampling rates. The system will provide data on peak and mean pressure, number of sensors activated, minimum and maximum pressure, and the location of the center of pressure. Some systems have the capacity for a split screen that displays the pressure map on one side and a video recording on the other. Another useful feature is the ability to define a particular area of the pressure map for which the system will generate pressure statistics. The breadth of information that these systems provide is both useful and a distraction. Although data showing peak and mean pressure seem easy to interpret, there is little consensus on what is desired pressure at the seat/buttock interface. Different ways of interpreting these data will be discussed below in the discussion of a pressure mapping protocol.

Ferguson-Pell and Cardi (1993) completed an evaluation of three computer-based pressure mapping systems. Although this work evaluated technology that is dated, it continues to influence thinking about pressure measurement systems as it applies a systematic protocol, involves both consumers and users, and identifies key parameters that must be considered in both the selection of a pressure mapping system and interpretation of the resulting data. The three systems that were evaluated included: the Force Sensing Array (Vista Medical), with a 15 × 15–cell array of force-sensing resistors, the Talley Pressure Monitor (TPM, Progressive Medical), consisting of an array of bladder-type sensors, and the Tekscan Seat (Tekscan Inc.), with an array of 2056 force sensors. With these systems, Ferguson-Pell and Cardi (1993) carried out “bench tests” to determine the properties of the sensors under controlled loads. The measurement variables of interest were accuracy, linearity and reproducibility, hysteresis, and stability (Ferguson-Pell and Cardi, 1993). In other words, they measured the relationship between the pressure measured by each system and a known applied pressure, creep, and hysteresis. These were examined with planar and contour loads under laboratory conditions and across four different pressure relieving cushions, with five wheelchair users as subjects. The four cushions used to evaluate the performance of each of the pressure mapping systems included (1) foam, (2) gel, (3) hybrid ( Jay), and (4) air filled (ROHO). The actual results of this work are less critical today because of the changes that have occurred in both measurement systems and cushion technology. However, this study remains an important one because of its use of a systematic research pro- tocol and identification of critical factors that influence the reliability of pressure mapping systems.

A recent study involved a similar comparison of more current pressure mapping technologies (Hadcock et al., 2002). Incremental loading, low threshold, and stability

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B

A

Figure 6-17 Pressure measurement system. A, Map with an array of sensors. B, Sample display of an individual’s pressure distribution profile (Courtesy Vista Medical, www.pressuremapping.com.)

(creep) of the F-scan FSA and Xsensor systems were evaluated under static and dynamic conditions by using planar and curved surfaces. The curved surface was cylindrical; quite different from a contoured seating surface, so the results of this aspect of the study must be interpreted with caution for the purposes of seating intervention. This study involved bench testing and did not include measurement with any wheelchair users. The results on a flat surface indicated that the FSA system was the most accurate, followed by the Xsensor and the F-scan. Creep was similar for the Xsensor and F-scan (17.62% and 17.23%, respectively) systems, and both were better than the FSA system (19.54%) (Hadcock et al., 2003). The Xsensor was better at detecting pressures under light loading conditions.

The studies by Ferguson-Pell and Cardi (1993) and Hadcock et al. (2003) provide some evidence for the difference in performance across pressure mapping systems. In addition to the performance characteristics evaluated in these studies, the selection of a system will depend on familiarity with the technology, the specific purpose (e.g., clinical evaluation versus research), and the functionality of the systems as they meet the needs of the user.

A second major issue with respect to pressure mapping is the identification of an accepted protocol for clinical use. There is no compelling evidence in the literature to suggest a particular number above which a pressure ulcer will certainly develop. Consequently, pressure mapping in the clinical situation is used to make comparisons among various cushions so that the clinician can rank the cushions for their ability to distribute pressure as measured by the pressure mapping systems. Swaine (2003) has developed a protocol for both obtaining and interpreting pressure measurements that is becoming more prevalent internationally. Swaine describes a consistent setup of the equipment and cushions to be evaluated, an initial check of the equipment, length of recording time, palpation of bony prominences, and documentation. She also suggests that interpretation of the results is based on peak pressure, the area of the client’s buttocks that are in contact with the pressure mat, and any asymmetries of pressure distribution.

Swaine’s work provides a useful basis for clinicians using pressure mapping to determine the optimal cushion for their clients’ needs. Caution is still advised because questions remain about a protocol and the interpretation of the data. For example, Swaine (2003) suggests that peak pressure is determined by taking the average of the four highest sensor cells around a bony prominence, whereas Dunk and Callaghan (2005) take the average of all sensors within 10% of the cell, measuring the highest peak pressure. Swaine rec- ommends that clients sit on a cushion for 8 to 10 minutes, whereas Stinson, Porter, and Eakin (2002) suggest that 6 minutes is sufficient. Pressure gradient rather than absolute pressure has been suggested as a better indicator of risk for development of a pressure ulcer, but there is no consensus on

what constitutes an acceptable gradient. These concerns suggest that, although pressure mapping remains a very use- ful tool its augment clinical judgment, it does not replace it.

Behavioral strategies to reduce the risk of development of pressure ulcers were identified earlier. Two main technologies exist to manage pressure for persons who use wheelchairs: pressure relief cushions and tilt and recline components on wheelchairs. The latter will be discussed in Chapter 12. Numerous studies have measured characteristics and prop- erties of a variety of pressure relief cushions. The majority of investigations have used tissue interface pressure as the basis for comparing these products. Some studies have also compared changes in transcutaneous oxygen tension and capillary blood flow. Although it has been shown that seating technologies play a significant role in pressure ulcer preven- tion by reducing the mechanical load on the tissue, there is no evidence that one type of pressure-reducing device works better than all others under all circumstances (Brienza et al, 2001; Conine et al, 1994; DeLateur et al, 1976; Ferguson-Pell et al, 1986; Garber, Krouskop, and Carter, 1978).

PRINCIPLES OF SEATING FOR COMFORT

This section considers seating and technologies that address that comfort. There are three distinct populations who can benefit from seating technologies for comfort: (1) wheel- chair users who have sitting discomfort and pain (e.g., individ- uals with postpolio syndrome, amyotrophic lateral sclerosis, and multiple sclerosis), (2) the elderly, and (3) individuals with low back pain, which can keep them from effectively performing their jobs. For individuals in any one of these populations, discomfort in seating can lead to a decreased ability to participate in activities of daily living. In cases of severe discomfort, the individual may be restricted to bed rest for some or all of the day, which further reduces the individ- ual’s ability to function and can lead to medical problems as well. There are unique technologies for each of these popu- lations, but the commonality is that they enhance comfort in the seated position.

In comparison to the other two categories of need, the technologies available to meet the comfort seating needs of individuals fall far short. There are a number of reasons for this. One is that equipment that is deemed necessary for comfort typically is not paid for by third-party funding sources because it is not considered a medical necessity. Another reason is that there is very little agreement among researchers on how to define and assess comfort and discom- fort (Hobson and Crane, 2001). Although much research has been done to assess comfort, it is a difficult variable to objectively measure because it can be highly subjective and involve multiple factors. A cushion that is described as com- fortable by one individual may feel uncomfortable to another.

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Researchers have also been unsuccessful in tying discomfort to quantitative measures such as posture, muscle fatigue as indicated by electromyographical measurements, or seat inter- face pressure (Hobson and Crane, 2001). The lack of out- comes relating to the effectiveness of seating products said to promote comfort makes it necessary for clinicians to use a trial-and-error approach to recommending equipment for the consumer.This can be costly and is often not funded by third- party sources. In turn, without funding at the clinical level for such products, there is no financial incentive for manufacturers to address this unmet need. It is necessary that those involved in this industry determine the best way to assess the many factors of discomfort and comfort. Only then can the efficacy of the current technologies for this population be carefully evaluated and new technologies be developed.

TECHNOLOGIES FOR SEATING AND POSITIONING MANAGEMENT

There is considerable overlap between the technologies used to address goals related to postural control, tissue integrity, and comfort. Further, many clients require seating that addresses two or more of these goals. Seating technologies in general will be discussed, with identification of their specific application to these goals where appropriate. This section is divided into two components: the design and the construc- tion of the seating system and the properties of the materials used to construct it. The evaluation process described at the beginning of this chapter guides the selection of the most appropriate system.The client should be allowed a trial period of use of the system because comfort and functional issues will become evident with use of the system over time.

Design and Construction of Seating Systems

The design of the seating system refers to the degree of contouring present in the seat and back and the degree of adjustability that is present in the components. These technologies range from systems that are relatively flat, without any contouring to match the shape of the body segments they support, to custom-contoured systems that are constructed to match as closely as possible the body contours of the user. Prefabricated technologies are available so that the ATP no longer needs to construct the compo- nents in the seating system.

Planar. Planar technologies are flat surfaces that support the body only where it easily comes in contact with the body, such as at bony prominences. In general, they are appropriate for individuals who require minimal support. Other position- ing components can be added to this basic structure if addi- tional support is required. Planar foam cushions, as shown in Figure 6-18, are designed from flat blocks of foam, which

can be highly adaptable. These blocks can be fabricated with one layer of a selected thickness (up to 4 inches) and selected density of foam, or they can be fabricated from multiple densities and varying thicknesses of foam (Hobson, 1990). In the latter case, for example, a piece of a stiff foam that is 1 to 2 inches thick might be used on the bottom to provide a stable base and a 3⁄4- to 1-inch-thick piece of soft foam could be placed on top for pressure relief. Planar foams can also be adapted by cutting out (e.g., under the ischial tuberosities) or building up areas as necessary for pressure distribution or postural management.

Prefabricated. Prefabricated planar components are made in standard sizes to fit a wide range of individuals. The back and seat surfaces are generally plywood or molded plastic pieces to which foam has been attached. Lateral sup- ports and an abductor for pelvic and hip support can be attached with hardware to the basic seat, and lateral supports for trunk stability can be attached to the back section (Figure 6-19) (Adaptive Engineering Lab, Inc., www.aelseating.com). The seat and back are attached to the wheelchair frame with interfacing hardware once the upholstery has been removed. Much of the hardware that interfaces the various components can be adjusted for angle, width, and depth. The advantage of having adjustable components is that they allow the system to be modified for growth or postural changes.

Custom Fabricated. Custom-fabricated planar systems are made of similar materials and design as prefabricated systems, but the dimensions of the seating surface and components are customized to fit the individual. These systems can be fabricated on site directly with the consumer, or specifications of the consumer’s measurements can be sent to a manufacturer for fabrication. The density of the foam pieces can also be selected to accommodate the needs

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Figure 6-18 Planar foam cushion.

of the individual. Lateral supports, headrests, and other components are added to the basic foam and plywood (or plastic) structure. This approach can be highly labor inten- sive and is being replaced at many facilities as a result of the advent of a large array of off-the-shelf technologies.

Standard Contoured Modules

Contoured technologies are useful for individuals with moder- ate seating and positioning needs for postural management

or who are at low risk for pressure ulcer development. These technologies use curved surfaces that more closely match the shape of the human body. The amount of contact that the body has with the seating surface is increased by contouring the seating surface to the person’s body, providing increased support and control. Further, a generic contoured cushion will distribute pressure across the seating surface and will fit people within a certain size range. This approach is also generally less costly than a custom-contoured cushion. The Matrix is one example of a standard contoured cushion (Figure 6-20) (Invacare, www.invacare.ca).

Custom Contoured

The cushion that provides the greatest amount of body contact and therefore the most support is one that has been shaped, or custom contoured, to the individual’s body. A number of technologies are available to achieve a custom-contoured system. One example is shown in Figure 6-21. These types of systems differ primarily in terms of the fabrication techniques used and whether the fabrica- tion is completed on site or in a central location. The disadvantages of custom-contoured support surfaces include the following: transfers to and from the system are more difficult; the system is static and has no dynamic properties, thus limiting the individual to one fixed position; and there is limited ability within the system to allow for growth of the individual.

Foam in place systems allows the ATP to fabricate a custom-contoured cushion on site. The client is placed in a frame that has a flexible covering over one side. This covering is matched to the shape of the person, and he or she is positioned in the most desirable seated posture. The foam materials are then added to the frame and allowed to expand to contour to the person’s shape. The person is removed from the frame, and the foam is allowed to harden for several hours. Once the foam hardens, the flexible covering

204 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

Figure 6-19 Planar seating system with positioning components. (Courtesy Adaptive Engineering Lab, Inc., www.aelseating.com.)

A B

Figure 6-20 Matrix cushion. A, Child’s version. B, Adult version. (Courtesy Invacare Corp., www.invacare.ca.)

is removed. Further shaping of the foam can be completed by hand at this time. The foam is encased in a fabric cover. The foam can then be attached to a solid backing (usually plywood or plastic) and mounted to the wheeled base. This approach can be used on site, and a cushion can be com- pleted in about 12 hours.

A vacuum consolidation process seats the client on a latex bag filled with beads (Lemaire et al, 1996). This bag is placed on top of a wheelchair or fitting chair. The ATP assists the client to achieve an optimal position to support goals of function, pressure relief, or comfort. The latex bag is then manipulated to conform to this position and the vac- uum is used to draw the air out of the bag, consolidating the enclosed beads. At this stage, the cushion can be fabricated either on site by a foaming procedure or sent to a central manufacturer for remote fabrication.

Seating simulators use technology that allows the ATP to map the client’s body contours, which are then digitized. Computer-aided manufacturing technology is then used to fabricate the cushion or back. The process of determining the optimal cushion or back shape is similar to that described for vacuum consolidation. A simulator chair is used that allows multiple adjustments to manipulate seat depth, seat to back angle, and other common wheelchair configurations. An initial baseline reading is taken without the client seated in the simulator. Once the client is com- fortably positioned in the chair, mechanical plungers are positioned to simulate the optimal seated position of the client. This information, along with the baseline reading, is transferred to a pressure-sensitive data recording sheet.

This sheet is then sent to a central fabrication facility, along with other recommendations related to foam density, special construction related to pressure relief (e.g., use of different foams), and required accessories such as laterals and strapping systems. The Shape Sensor system by Invacare (www.invacare.com) is an example of this technology.

Prefabricated Adjustable Backs

Prefabricated adjustable backs have become available in recent years. These products provide a large degree of adjustability that can be accomplished in the clinical setting. The Infinity Back is an example of an adjustable back. The ATP can make adjustments on the basis of an optimal seated position determined by a mat assessment. These backs allow the clinician to adjust height, depth, width, back angle, and placement of the laterals. Some of these systems allow the ATP to create a biplanar back in which the upper and lower segments of the back are set at differ- ent angles. This configuration is often used to provide specific postural control. Although the pivot point can be placed at any spinal level, when placed at the level of the posterior superior iliac spine, it can assist with control of the pelvis. Studies have investigated the effect of pelvic stability on function (Miller Polgar et al, 2000; Rigby et al, 2001;), but there have been no clinical studies that have evaluated the effect of this particular back configuration on postural control and subsequently function.

PROPERTIES OF MATERIALS USED TO CONSTRUCT SEATING SYSTEMS

An understanding of the properties of the materials used in seating technologies will assist in the selection of appropriate cushions. Sprigle (1992) identifies and describes five properties of cushion materials: (1) density, (2) stiffness, (3) resilience, (4) dampening, and (5) envelopment.

Density of a material is the ratio of its weight to its volume. A greater density generally means a more durable material, but not always. Low-density materials will fatigue faster than high-density ones under the same loading conditions. Stiffness of a material describes how much it gives under load. In a cushion, this is the distance that the person sinks into the cushion. Soft materials may bottom out, but failure to compress can also lead to an increase in seating pressures and tissue breakdown. The International Standards Organization standards also describe lateral and forward stiffness that describes the response of the cushion to a lateral force. It is easier to slide on a cushion with low stiffness, but the shearing forces are higher, resulting in a cushion with less stability. Sliding resistance is a cushion property related to friction. A cushion with high resistance

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Figure 6-21 Custom-contoured seating system. (Courtesy Invacare Corp., www.invacare.com.)

limits how much the user slides, helping to support upright posture, but consequently makes transfers more difficult.

Resilience is the ability of a material to recover its shape after a load is removed or to adjust to a load as it is applied. Short-term resilience is the immediate recovery when a load is altered, such as when someone shifts weight on a seat cushion. Long-term resilience is the overnight recovery of a cushion that has been loaded and then unloaded. Dampening is the ability of the cushion to soften on impact; it is best observed by dropping a relatively heavy object on the material. If the object sinks into the material, then dampening is occurring. If it bounces off, or if the material does not react to the object, then the material is poorly dampened. This is the “shock absorber” feature of cushion materials and is important in minimizing the transmission of forces from the ground to the individual as they travel over rough surfaces or obstacles. Envelopment is the degree to which the person sinks into the cushion and the degree to which the cushion surrounds the buttocks. Good envelopment promotes stability and helps reduce peak pressures. Recovery refers to the degree to which a cushion returns to its preloaded state when a load is removed.

Classification of Cushion Technologies

Sprigle, Press, and Davis (2001) describe uniform terminology for classification of the material used to construct wheel- chair cushions. They described the following categories of cushions: (1) made from cellular materials, (2) containing fluid, and (3) other constructions.

Cushions Made From Cellular Materials. This cate- gory includes cushions made from “foam,” “flexible matrix,” “viscoelastic foam or matrix,” and “nondeforming foam or matrix” (Sprigle, Press, and Davis, 2001, pp. 451-2). Over the years, foams have been the material most commonly used in the fabrication of cushions. Polyurethane or latex foams come in a variety of thicknesses and densities and are often characterized by their cell structures. There are two commonly used cell structures for foams: open cell and closed cell. Open-cell foams have interconnected, perforated membranes that permit airflow between the cells and result in better ventilation (Tang, 1991). This type of foam is often less dense because of the air captured in the open cells. Open-cell foams absorb fluids, which makes them difficult to clean. Closed-cell foams are composed of individual structures encased in a membrane. These foams are generally less compliant than open-cell foams, and airflow is restricted. Examples of these foams include polyurethane and latex (open cell) and ethafoam (closed cell).

Foam cushions are typically lightweight and inexpensive. Foams compress with the application of weight, which results in good envelopment. The amount of compression

depends on the stiffness of the foam. Although soft foam will compress and allow the person to sink in more, a foam that is too soft might bottom out. Because foams have a tendency to trap heat near the body, their thermal features are considered to be poor. In general, the short- and long-term resilience of foam is good, but again this varies depending on the structure and density of the foam. The two main dis- advantages of using foam are that it (1) is prone to deterio- ration from light and moisture and (2) has a tendency to loose its resilience over time. Replacement of the foam depends on the type of foam and how much time the user spends sitting on the cushion.

Viscoelastic Foam or Matrix. Viscoelastic foams were originally developed by the National Aeronautics and Space Administration for space travel. These foams, because of their high viscosities, tend to resist deformation if pressed quickly, but they will accommodate slowly to a constant load. They also have memory, which delays their return to the original shape. This time-dependent property is the most distinguishing feature of this type of foam (Sprigle, Press, and Davis, 2001). Viscoelastic foam also has good thermal properties and good envelopment. The resilience and dampening properties are variable depending on the density and other properties (Sprigle, 1992). Sunmate (www.sunmate cushions.com), T-foam, and Tempur-Med (www.tempurcanada.com) are examples of this type of foam (Figure 6-22).

Flexible Matrix. Honeycomb cushion material is made from an array of thermoplastic elastomers. The material consists of layers of interconnected open cells that flex when pressure is applied. The flexibility of the cells results in a cushion that conforms to the user’s body shape, providing pressure relief. These cushions have good resiliency. The open cells allow air to flow through, which keeps the cush- ion cooler and prevents moisture. Cushions that use flexible

206 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

Figure 6-22 Examples of Viscoelastic foam. Sunmate foam. (Courtesy Sunmate, www.sunmatecushions.com.)

matrix technology have both planar and contoured versions. Stimulite by Supracor (www.supracor.com) (Figure 6-23) is an example of a cushion with a flexible matrix technology.

Cushions Containing Fluid Air Filled. Air-filled cushions consist of a sealed receptacle that holds air. The cushion may be configured to allow the air to circulate within the whole receptacle, or it may be divided into compartments to better control the air flow. Air-filled cushions distribute pressure from high-pressure areas, such as the ischial tuberosities, to areas where there is less pressure. These cushions have good long-term and short-term resilience. The pressure-relieving properties of this type of cushion are typically good; however, the ability of this cushion to envelop the user and thus its effectiveness are dependent on the amount of inflation. An air-filled cushion that is overinflated will not envelop the buttocks and will result in increased pressure at bony prominences and reduced sitting stability. Underinflation of the cushion can result in the air being pushed away from the high- pressure areas, allowing them to “bottom out” against the hard sitting surface of the seat. Persons who lack sensation may not be able to feel whether the cushion is underinflated.

Commonly used air-filled cushions are the ROHO and Bye Bye Decubiti.The ROHO cushion (Crown Therapeutics, www.crownthera.com) consists of a number of rubber- balloon cells that are interconnected at the base to allow for airflow among cells (Figure 6-24). It is available in a number of configurations, including a high and low profile (4- and 2-inch cells, respectively) and various inflation configurations. The multiple compartments allow the air to be regulated in each compartment separate of the other compartments. Air-filled cushions are generally lightweight, and the materials they are made of do not deteriorate over time.

A main disadvantage to these cushions is that they must be properly inflated, with consistent monitoring of the inflation to provide maximal benefits. Puncture and tears also occur, which influence their function. However, there is some evi- dence to support the superior pressure-relieving properties of an air-filled cushion over other pressure relief (Koo, Mak, and Lee, 1996; Shechtman et al, 2001). Viscoelastic Fluid. A viscoelastic fluid is relatively stiff, yielding to small forces (Sprigle, Press, and Davis, 2001). The elastic component refers to the fluid’s ability to store energy (Sprigle, Press, and Davis, 2001). The viscous property refers to the degree to which fluid molecules move across each other. A highly viscous fluid will not flow easily because the molecules do not easily slide across each other. A low-viscosity fluid or nonviscous fluid (such as water) will flow easily (Figure 6-25). High viscosity means

P A R T III The Activities: General Purpose Assistive Technologies 207

Figure 6-24 The ROHO High Profile air-filled cushion. (Courtesy Crown Therapeutics.)

Figure 6-25 Example of viscoelastic fluid cushion, J Extreme.

Figure 6-23 Flexible matrix technology, Stimulite cushion. (Courtesy Supracor Inc., www.supracor.com.)

that envelopment is poor and short- and long-term resilience is poor. These cushions have good dampening and thermal properties (they conduct heat away from the body) and provide a more stable base than does an air cushion. However, they are affected by temperature and will freeze in cold weather. In addition, some gels that are encased in a large bladder can shift, allowing the user to sit on the hard support surface. Cushions with this con- struction must be kneaded to ensure that the distribution of the gel is uniform to prevent contact with the support surface.

Alternating Pressure Cushions. Research (Kosiak, 1959; Reswick and Rogers, 1976) has documented a rela- tionship between the amount of pressure applied and its duration and the development of pressure ulcers. In a study described earlier, it was found that the alternating pressure cushion was the only seating surface to intermittently bring pressures within the range of capillary blood pressure (Kosiak et al, 1958). All the cushions described thus far are static cushions, which have been designed on the premise that (1) they redistribute pressure over the sitting surface and (2) the individuals using them also need to follow through with pressure relief activities. Alternating pressure devices are designed on the basis that weight-bearing sur- faces can tolerate high pressures for a time if alternated with increments of no pressure.

The principle of intermittent pressure relief is imple- mented in commercially available cushions by use of an oscillating pump to alternately inflate bellows arranged in rows (Hobson, 1990). Each individual elastomeric bellow (typical cushions have arrays of 48 arranged in eight rows of six) can be inflated individually or in groups. Generally, rows are inflated together. One approach couples every third row of the array of bellows. During operation, two of the coupled rows are inflated and one is deflated, which relieves pressure over one third of the seating surface; then the next third of the array is deflated, and so on. An alternative approach automatically cycles only the back four rows (out of eight total) under the ischial tuberosities. Each row is sequentially inflated and deflated to provide intermittent pressure relief to local tissue. These cushion systems use a recycling air pump powered by a battery to inflate the bellows. If the pressure pump should fail to operate in these systems (e.g., the battery becomes discharged), the cushion can still be used as an air-filled cushion. Because of the added weight, the need for recharging of the battery, and the cost, these seating devices have not been as widely distributed as other cushion types.

Hybrid Cushions. Hybrid cushions consist of a combi- nation of the materials described above. The most typical combination is a closed-cell foam base with a membrane that contains gel, viscous fluid, or air that is placed on top or

inserted in a cutout. This method provides a combination of good envelopment, good thermal properties, pressure relief (because of the flotation materials), and good support and dynamic properties, which are provided by the foam base (Sprigle, 1992). The series of Jay cushions are commonly used hybrid cushions that consist of a combination of a stan- dard-contoured, high-density foam base with a gel-filled pad that sits atop the foam base. The pad can be purchased in different configurations, such as an overfilled pad or pads with the gel sectioned off into quadrants, which prevents the pooling of gel into certain areas. The Cloud cushion from Ottobock (www.ottobock.com) (Figure 6-26) is an example of a hybrid cushion that has a foam and air- holding membrane that sits on top of a standard-contoured foam base. The overall properties of these types of cushions depend on the type of container and on the properties of the foam base.

Cushion Covers

Selection of a cover for a seat or back cushion can be as important as the determination of the material used to make the cushion because an improper cover can negate some of the benefits of that material. The cover selected should conform integrally to the cushion’s contours, particularly in nonplanar systems. It should not interfere with the envelopment properties of the cushion nor add to shearing and friction. A cover that is too tight will prevent the client from sinking into the contours of the cushion. One that is too large will wrinkle, creating additional pressure points.

The ATP should know how the fabric handles moisture, either as a result of incontinence or perspiration. Most cush- ions will be used in hot, humid conditions for at least part of the year, so perspiration is an issue even when incontinence

208 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

Figure 6-26 Example of a hybrid cushion. (Courtesy Otto Bock, www.ottobock.com.)

is not a concern. Many technical fabrics, blending Lycra and polyester, wick moisture away from the body, which is an important consideration when prevention of pressure ulcers is a goal. The cushion cover should be easy to remove and clean.

SEATING FOR PRESSURE DISTRIBUTION AND POSTURAL SUPPORT

Individuals who are at risk for development of pressure ulcers can benefit from proper positioning in the wheelchair as well. In fact, it is recommended that positioning be addressed first because postural alignment often results in changes in pressure distribution (Minkel, 1990). Through postural alignment, pressure can be distributed more evenly; postural deformities, such as pelvic obliquity, scoliosis, and kyphosis, can be prevented; back pain can be alleviated; and stability can be increased. These changes will influence the individual’s mobility, energy expenditure, and function.

Many of the principles described regarding sitting pos- ture and postural control apply to individuals at risk for pressure ulcer development as well. Some of the technolo- gies for postural control are beneficial for persons with spinal cord injuries, and new technologies that specifically address the needs of this population have been developed. Some basic strategies for positioning for postural manage- ment for this population are described.

A cushion, without a firm base, placed in the seat will not totally eliminate the hammocking effect, and eventually the sling seat stretches further and the cushion conforms more to the sling. Simply installing a solid seat can minimize the hammocking effect of the sling upholstery. Solid seats can be made from a 3⁄8-inch sheet of plywood, or plastic seats can be purchased from many cushion manufacturers. Any of the cushions described earlier can then be placed on the solid seat. The upholstery back of the wheelchair does not provide lumbar support and promotes a sacral sitting position with kyphosis of the spine. The upholstery back can be replaced with a solid, contoured back that is commercially available (e.g., Varilite Evolution Back or J2 Back) (Figure 6-27 shows an example of a commercially available back) or cus- tom made of foam. The seat back should be assessed for appropriate height and seat-to-back angle. It is recom- mended that the back be reclined approximately 15 degrees to help stabilize the trunk and prevent forward loss of bal- ance. The back height is determined by the amount of sup- port needed by the individual. Many persons with paraplegia have adequate trunk strength and wish to preserve mobility (particularly for sports), so they prefer lower backs on their wheelchairs and prefer not to use trunk-positioning compo- nents. Persons with C4, C5 quadriplegia, with less trunk control, can benefit from a higher seat back that supports all

or part of the scapulae, and those with C1 to C3 spared will require headrests.

Technologies to Enhance Sitting Comfort for Wheelchair Users

In a study that assessed the satisfaction of wheelchair users, comfort was rated as the most important variable for a wheelchair seating aid (Weiss-Lambrou et al, 1999). At the same time, comfort was rated as the least satisfying variable among these wheelchair users. The reasons stated for dissat- isfaction related to comfort included seat cushions that caused pain and discomfort, fatigue, uncomfortable head- rests and thoracic supports, sliding in wheelchair seat caused by discomfort, and poor posture as a result of unsuitable installation. Comfort is also related to the contact surface between the seating system and the person. For example, materials that provide good air exchange, maintain an even temperature, and control moisture are more likely to provide a comfortable sitting climate.

Wheelchair users who have discomfort and chronic pain need seating systems that allow them to relieve the discomfort and participate fully in activities of daily living. These needs are best addressed after a thorough mat assessment that identifies the user’s most comfortable seated position and the combination of technologies identified above that best addresses comfort needs. (Mobility technologies that provide users with the ability to adjust their positions in the wheelchair will be discussed in Chapter 12).

P A R T III The Activities: General Purpose Assistive Technologies 209

Figure 6-27 Example of a commercially available back.

Technologies That Increase Ease of Sitting for the Elderly

People are living longer, which means that the number of well elderly and those in need of supervised care is growing considerably. As an individual ages, mobility may be reduced as a result of acute illnesses or trauma, such as stroke, hip fracture, or progressive conditions such as arthritis. Consequently, it is likely that the amount of time the individual spends sitting increases. The goal of seating in this category depends on the individual’s needs and skills, as it does for the other categories. Just as there is a range of needs for the elderly population, there is also a range of seating technologies. Seating technologies for the aging population can be matched to the level of functional mobility the individual has: (1) ambulatory (2) mobile, nonambulatory, and (3) dependent mobile (Fernie and

Letts, 1991). Chairs are needed that promote comfort, safety, ease of ingress and egress, and propulsion if necessary.

SUMMARY

This chapter has shown the potential outcomes that can be achieved through seating in three primary areas of need: postural control, tissue integrity, and comfort. Procedures for evaluation and matching of device character- istics to the individual’s needs were presented. Basic principles of biomechanics frequently used in seating and positioning were discussed. Different types of seating technologies and cushion classifications were described, along with their appli- cation to the three primary goals of seating.

210 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

Study Questions

1. Describe the three primary goals of seating interven- tion. What are the key elements of a mat assessment? Describe each of these.

2. Describe three additional factors that the ATP should consider when designing a seating system.

3. Describe the influence of the physical, sociocultural, and institutional contexts on design of a seating system.

4. What are the three types of force? Why are they rele- vant to seating and positioning?

5. What is meant by the center of pressure, and how does it relate to seating and positioning systems?

6. Describe the basic premises underlying seating inter- vention for postural control.

7. Why is the pelvis the starting point when seating for postural control? Describe the major approaches used to obtain alignment and control of the pelvis.

8. Describe the three spinal deformities that may occur. 9. List three methods used to support the trunk in pos-

tural control seating systems, and describe when each method is indicated.

10. Describe how the head can be positioned posteriorly, anteriorly, and laterally. What factors lead to the use of each of these?

11. What is the major cause of pressure ulcer development? What are other factors that contribute to the develop- ment of pressure ulcers?

12. Define hysteresis and creep. Describe how each of these affects the reliability of pressure map measurements.

13. Describe Swaine’s pressure mapping protocol. Describe the output of pressure mapping systems. Discuss two controversial aspects of pressure measurement.

14. What is a honeycomb cushion? What advantages does it have over other approaches?

15. How do viscoelastic fluid-filled and foam cushions differ? List an advantage and disadvantage of each.

16. What are the primary populations for whom comfort is the major goal in developing a seating system?

17. Identify the reasons why there are limited technologies available for populations for whom comfort is the major goal.

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212 C H A P T E R 6 Seating Systems as Extrinsic Enablers for Assistive Technologies

Human/Assistive Technology Interface

Chapter Out l ine

ELEMENTS OF THE HUMAN/TECHNOLOGY INTERFACE Control Interface Selection Set Selection Methods Direct Selection Indirect Selection The Processor: Connecting the Human/Technology Interface to the Activity Output

Keyboard- and Mouse-Emulating Interfaces General-Purpose Emulators On-Screen Selection Sets Switch-Controlled Computer Keyboard and Mouse Emulation Communication Devices as Alternative Computer Inputs

CHARACTERISTICS OF CONTROL INTERFACES Spatial Characteristics Activation and Deactivation Characteristics Method of Activation Effort Displacement Deactivation Flexibility Durability and Maintainability Sensory Characteristics Rate Enhancement Direct Selection Rate Enhancement Scanning Rate Enhancement

SELECTING CONTROL INTERFACES FOR THE USER Applying the Outcomes of Needs Identification and Physical-Sensory Evaluations to Control Interface Selection

Control Enhancers: Interface Positioning, Arm Supports, Mouthsticks, Head Pointers, and Hand Pointers

CONTROL INTERFACES FOR DIRECT SELECTION Keyboards Standard Keyboards Built-in Software Adaptations to the Standard Keyboard Ergonomic Keyboards

Expanded Keyboards Contracted Keyboards Special-Purpose Keyboards Automatic Speech Recognition as an Alternative Keyboard

Touch Screens and Touch Tablets TongueTouch Keypad Access for Users With Cognitive Limitations Eye-Controlled Systems Tracking of Body Features Brain-Computer Interface Standard and Alternative Electronic Pointing Interfaces Mouse Keypad Mouse Trackball Continuous Input Joysticks Head-Controlled Mouse Comparison of Key-Pad and Head-Controlled Mouse Alternatives

Light Pointers and Light Sensors Modifications to Keyboards and Pointing Interfaces Keyboard Layouts Keyguards, Shields, and Templates Technologies for Reducing Accidental Entries

CONTROL INTERFACES FOR INDIRECT SELECTION Selection Techniques for Scanning Selection Formats for Scanning Coded Access Types of Single Switches Switch Arrays, Discrete Joysticks, and Chord Keyboards

INTERNET USE BY PERSONS WITH PHYSICAL DISABILITIES

OTHER CONSIDERATIONS IN CONTROL INTERFACE SELECTION

Multiple Versus Integrated Control Interfaces Mounting the Control Interface for Use

213

C H A P T E R 7

The human/technology interface is a major part of theassistive technology component of the human activityassistive technology model. Bailey (1996, p. 173) defines an interface as “the boundary shared by interacting compo- nents in a system” in which “the essence of this interaction is

communication or the exchange of information back and forth across the boundary.” The human/technology interface is the boundary between the human and the assistive tech- nology across which information is exchanged. This exchange of information is bidirectional and includes both

214 C H A P T E R 7 Human/Assistive Technology Interface

Key Terms

Abbreviation Expansion Acceptance Time Accessibility Options Activation Characteristics Automatic Scanning Circular Scanning Coded Access Command Domain Concept Keyboards Continuous Input Control Enhancers Control Interface Digital Recording Direct Selection Directed Scanning Discrete Inputs Distributed Controls

Easy Access Emulation General Input Device–Emulating Interface

Graphical User Interface Group-Item Scanning Indirect Selection Input Domain Integrated Control Inverse Scanning Linear Scan Multitasking On-Screen Keyboard Parallel Port Prosodic Features Rate Enhancement Rotary Scanning

Row-Column Scanning Scanning Selection Methods Selection Set Sensory Characteristics Serial Port Spatial Characteristics Speech Synthesis Step Scanning Text-To-Speech Programs Transparent Access Universal Access USB Port Word Completion Word Prediction

Learning Objectives

On completing this chapter, you will be able to do the following:

1. Describe the elements of the human/technology interface and its role within the assistive technology component of the human activity assistive technology model

2. Describe the characteristics of control interfaces 3. Identify and define the basic selection methods 4. Describe the means by which the user’s physical control can be enhanced 5. Discuss a framework for control interface decision making 6. Identify technologies for direct selection 7. Identify technologies for indirect selection 8. Discuss the outcomes that can be achieved through implementation of a motor training program and how

technology can be used to improve motor response 9. Describe the computer user interface

10. List the major components of a computer system and give the function of each component 11. Describe the major approaches to keyboard and mouse emulation 12. Describe the major approaches to electronic speech generation used in assistive technologies

DEVELOPMENT OF MOTOR SKILLS FOR USE OF CONTROL INTERFACES

OUTPUT COMPONENT OF THE HUMAN TECHNOLOGY INTERFACE

Speech Output

Digital Recording Speech Synthesis

SUMMARY

the interface from the person to the device used to control the assistive device and the interface that provides feedback regarding the device’s operation from the device to the person.

The exchange of information in the form of input to operate the device takes place by way of a control interface between the user and the device. It may vary from someone who needs an enlarged light switch to turn a light off and on to someone who needs to access a portable communication system with a single switch to someone who needs to con- trol a power wheelchair with a joystick. The exchange of information from the device to the person takes place through a visual or auditory display. These displays, which have an important role in providing feedback to the user, are also considered a component of the human/technology interface. The role of displays in specific assistive technology applications is discussed in subsequent chapters. Alternative displays for people with visual or auditory impairments are discussed in Chapters 8 and 9, respectively.

In this chapter we discuss the various control interfaces, their characteristics, the control methods that provide the link between the person with a disability and the device being controlled, and the use of electronically generated speech as an output for assistive technologies. A framework for matching control interfaces, control methods, and enhancement techniques to the user’s needs and skills is also presented.

ELEMENTS OF THE HUMAN/ TECHNOLOGY INTERFACE

The human/technology interface is more than just a piece of hardware with inputs into the device. There are actually three elements of the human/technology interface that contribute to the operation of a device: the control interface, the selec- tion set, and the selection method. These three elements are interrelated, and careful attention must be given to each ele- ment to have an effective human/technology interface.

Control Interface

The control interface (e.g., keyboard, joystick) is the hardware by which the human in the assistive technology system operates or controls a device. It is sometimes also referred to as an input device. The control interface generates from one to an infinite number of independent inputs, or sig- nals, defined as the input domain (Morasso et al, 1979). The input domain may be either discrete or continuous.

A control interface with discrete inputs is one in which each location has a fixed value representing a distinct result with no intermediate steps. For discrete interfaces, the size of the input domain is equal to the total number of targets available to the user. For example, a computer keyboard may have more than 100 keys, each representing a different letter

or symbol, which is the signal that is sent to the processor. Although a single switch has only one signal in its input domain, a dual switch has two signals. With a continuous input interface the inputs are continuous, with an infinite number of values. Interfaces that are continuous either vary in quantity along a range, as with a volume control, or main- tain an even quantity while providing a continuous input, such as driving straight ahead using a steering wheel to make small adjustments. A proportional joystick and a com- puter mouse both have a continuous input domain in which there can be an infinite number of possible input signals.

Selection Set

The selection set is the items available from which choices are made (Lee and Thomas, 1990). Selection sets can be represented by traditional orthography (e.g., written letters, words, and sentences), symbols used to represent ideas, com- puter icons, line drawings or pictures, or synthetic speech. The modalities in which the selection set is presented can be visual (e.g., letters on the keyboard), tactile (e.g., Braille), or auditory (e.g., spoken choices in auditory scanning).

The size, modality, and type of selection set chosen are based on the user’s needs and the desired activity output. Electronic aids to daily living (EADL) or a power wheel- chair typically have fewer items in the selection set than an augmentative communication device. The size may also vary according to the user’s skills. For example, an individual who spells and has good physical control has the skills to use the selection set of a standard keyboard, which consists of all the letters and function keys. Another individual who is work- ing on developing language and communication skills may have a selection set consisting of only two picture symbol choices displayed on a lap tray. Selection sets are discussed further in Chapter 11.

Selection Methods

There are two basic methods in which the user makes selec- tions by use of the control interface: direct selection and indirect selection. We refer to these as selection methods. Currently used indirect selection methods include scanning, directed scanning, and coded access.

Direct Selection. With direct selection the individual is able to use the control interface to randomly choose any of the items in the selection set. The consumer indicates his choice by using voice, finger, hand, eye, or other body move- ment. In this method of selection the user identifies a target and goes directly to it (Smith, 1991). At any one time, all the elements of the selection set are equally available for select- ing; that is, they are not time dependent. Typing on a key- board or even picking a flower from the garden is considered direct selection. Physically, direct selection requires refined,

P A R T III The Activities: General Purpose Assistive Technologies 215

controlled movements and it is the more difficult of the two methods. Cognitively, there is an immediate, direct result from the selection made; therefore, direct selection is more intuitive and easier to use. Figure 7-1 shows the input that is made by using direct selection to obtain the letter S. The various types of control interfaces that allow the individual to use direct selection are described in the section on select- ing a control interface for a user.

Indirect Selection. With indirect selection, inter- mediate steps are involved in making a selection. The most common indirect selection method is scanning. With scanning, the selection set is presented on a dis- play and is sequentially scanned by a cursor or light on the device. When the particular element that the individual wishes to select is presented, a signal is generated by the user. With an assistive device, the control interface used for scanning is a single switch or an array of two or more switches. Depending on the needs of the user, scanning can vary in the format used for the selection set and in the manner in which the control interface is used to make the selection. These various techniques are discussed later in this chapter.

Scanning and direct selection require different physical and cognitive skills. Scanning requires good visual tracking skills, a high degree of attention, and the ability to sequence. The advantage of scanning is that it requires very little motor control to make a selection. Ratcliff (1994) measured speed and accuracy in a four-level direction- following task carried out by children in grades 1 through 5 who were using scanning and direct selection. She found that subjects using direct selection made significantly more errors than those using scanning across all grade and diffi- culty levels. Overall error rates decreased with increasing grade level. Significant differences were also noted between second and third graders and between fourth and fifth graders at the second difficulty level. No other grade or difficulty level differences were statistically significant. Reasons cited for the differences in selection method error rates include the dependence on visual perceptual skills,

memory, and the vigilance and attention (necessity to wait for the desired selection) in scanning. Scanning is also more complex cognitively than direct selection because there are additional steps imposed between the user’s action (e.g., hitting a switch or key) and the resulting input. Ratcliff concludes that scanning is a more difficult task than direct selection even for nondisabled children, which has implications for electronic assistive device application.

Because scanning is inherently slow, there have been a number of approaches used to make it more efficient and faster for the user. Some of these involve the location of let- ters, word completion and prediction, and other text-based approaches. These are discussed in Chapter 11. However, many of these approaches can actually slow down the scan- ning because they require a larger amount of concentration by the user. An alternative approach is to automatically adjust the scanning rate (reduce the delay between rows, columns, and entries) and maximize the rate for an individ- ual user (Simpson and Koester, 1999). This approach uses a known text passage in which the user enters that passage at as fast a scan rate as possible. If the number of errors increases, the scan delay is increased (rate decreased) by use of a Bayesian probabilistic model. Simpson and Koseter found that, for non-disabled users, the automatic adaptation of scan rate had the potential to increase rate of text entry without the addition of task complexity that occurs in text- based methods.

Directed scanning is a hybrid approach in which the user activates the control interface to select the direction of the scan, vertical or horizontal. Then the device scans the selection set sequentially. When the desired choice is reached, the user sends a signal to the processor to make the selection. This signal is generated either by pausing at the choice, an acceptance time, or by activating another control interface to indicate the choice. In directed scanning, both the type of movement made and the point when the movement is made contribute to the selection (Vanderheiden, 1984). A joystick or an array of switches (two to eight switches) are the con- trol interfaces used with directed scanning. Figure 7-2 gives

216 C H A P T E R 7 Human/Assistive Technology Interface

Direct Selection

Finger or Pointer

Keyboard

Press S S

Input Output

Figure 7-1 Input required to obtain the letter S with use of direct selection. (From Smith RO: Technological approaches to performance enhancement. In Christiansen C, Baum C, editors: Occupational therapy: overcoming human performance deficits, Thorofare, NJ, 1991, Slack.)

an example of the input required to select the letter S using directed scanning with a four-position joystick.

Directed scanning requires more steps than direct selec- tion but fewer steps than single-switch scanning. The user needs to be able to activate and hold the control interface and to release it at the appropriate time. If the individual can pro- duce the movements required to use this method, the out- come is faster entry of the desired selections into the device.

Another form of indirect selection is coded access. In coded access the individual uses a distinct sequence of movements to input a code for each item in the selection set. Like the other two methods of indirect selection, intermedi- ate steps are required for making a selection. The control interface is a single switch or an array of switches configured to match the code. Morse code is one example of coded access, wherein the selection set is the alphabet but an inter- mediate step is necessary to obtain a letter. Morse code was developed to be very efficient by assigning the most fre- quently used letters the shortest codes. This efficiency can be useful in written or conversational communication. In addi- tion, Morse code does not require that a selection set be dis- played. The codes are usually memorized, although visual displays, diagrams, or charts can be used to aid in recalling the codes. Morse code and other coded access methods are described in greater detail later in this chapter.

Like scanning, coded access requires less physical skill than direct selection. The advantage of coded access over scanning, however, is that the timing of the input is under the control of the user and is not dependent on the device. The disadvantage is that it takes more cognitive skill, espe- cially memory and sequencing, than direct selection does.

Most current devices can be accessed by more than one type of control interface and selection method. The selection set on most devices can also be varied to match the user’s needs. From a manufacturing perspective, versatility of a device allows it to be applicable to a wider population, which

helps to contain the cost of the device and makes it possible to adapt to changing user needs and skills.

The Processor: Connecting the Human/ Technology Interface to the Activity Output

When the user activates the control interface, information is sent via a signal to the processor. The processor interprets the information and generates two signals that are converted to (1) feedback to any display that is being used and (2) an activity output, depending on the functions of the assistive technology system. The set of device functions is referred to as the command domain (Morasso et al., 1979). For example, the command domain of a joystick on a power wheelchair is typically configured so that the signal for the UP input is transformed into forward movement of the wheelchair, DOWN into reverse movement, LEFT into movement to the left, and RIGHT into movement to the right. That same joystick can be used to control a television set in which the same input domain of UP, DOWN, LEFT, and RIGHT becomes a command domain of television vol- ume up, volume down, channel up, channel down. In an electric feeder the command domain includes lifting up the spoon, rotating the plate, and putting the spoon back down. In a communication device the command domain is the meaning assigned to each input selection, including func- tions such as print and speak.

For every element in the command domain there must be a corresponding element in the selection set. The selection set is presented to the user by the selection method. For exam- ple, with direct selection each item in the selection set is labeled on the target itself. In direct selection the size of the input domain (number of independent signals) is equal to the size of the command domain. With indirect selection, the input domain has fewer signals than the number of ele- ments in the command domain. With scanning, each item in

P A R T III The Activities: General Purpose Assistive Technologies 217

Directed Scanning

Joystick

Scanning Array

SMove Joystick: Down Right Right Right Down

Input Output

Figure 7-2 Directed scanning showing input required to select the letter S. The user selects the direction of the scan, and the items in the selection set are scanned sequentially by the device. When the desired item is reached, the user makes the selection. (From Smith RO:

Technological approaches to performance enhancement. In Christiansen C, Baum C, editors: Occupational therapy: overcoming human performance deficits, Thorofare, NJ, 1991, Slack.)

the selection set is presented sequentially by the device. Thus we can see how the selection method connects the human/ technology interface to the command domain of the processor.

Keyboard- and Mouse-Emulating Interfaces. Many computer adaptations are mandated by the legislation described in Chapter 1 (e.g., Public Law 508). The best approach to adapting a computer for use by individuals with physical limitations is to begin with the simplest modifica- tions designed for the most minimal of physical limitations on the part of the user. We can then progress to more com- plex adaptations designed to accommodate even the most severely limited potential user. Transparent access is essential for effective access. This term describes two funda- mental concepts: (1) 100% of the functions of the computer must be adapted if the user who has a disability is to have full access and (2) all application software that runs on the unmodified computer must also run on the adapted com- puter. All the keyboard keys, including modifier (e.g., shift, control, alt) and special function keys, and all the mouse functions, such as point, click, and drag, must be available on the adapted input system. If a program (e.g., word proces- sor) works with the standard computer, then it should work with the adaptations. The adaptations also have to be con- sistent with the operating system of the computer and the hardware configuration (e.g., Windows).

There must be a bridge between the control interface and the computer to use many of the alternatives to keyboard or mouse, such as an expanded keyboard or a single switch, to access a computer. Sometimes this bridge is built into the control interface and other times it is separate. Because the control interface itself is only a switch (or set of switches in a keyboard), pressing a switch or key does not generate any meaningful information for the computer or other assistive device. To make the information meaningful, a decoder must be used (Anson, 1997). In the 1980s and 1990s the Trace Center at the University of Wisconsin developed a standard for general input device–emulating interfaces, or GIDEIs. The GIDEI standard defines the characteristics of a special-purpose processor that translates (i.e., decodes) the signals from the control interface so they match the command domain requirements of the computer. For example, if the computer application requires the use of ESC or DEL keys, then the input device must provide a way for the control inter- face to generate these key commands. For older devices, the decoding was accomplished through software in the com- puter, or an additional hardware component (the GIDEI). With the development of the USB standard, particularly the human interface device (HID) component, nearly all of the functions previously developed requiring a special-purpose GIDEI can now be accomplished through the USB inter- face (Novak and Olsen, 2001). The decoding previously car- ried out by the GIDEI is built into the control interface (particularly keyboards) and supplied to the computer

through the USB port. An additional advantage of the USB port is that it supplies power to the external device from the computer, which eliminates the necessity for an external power source for USB input devices and is especially valu- able for assistive technology applications based on portable computers. Additional software may need to be loaded into the computer to allow customization of the control interface selection setup (discussed later in this chapter). There are, however, challenges involved in using the USB HID stan- dard, and these can result in incompatibilities between assis- tive technology devices and between the device and the host computer (Vanderheiden and Zimmermann, 2002). The existing USB HID standard provides definitions for com- mon human input devices such as keyboards, mouse point- ers, joysticks, and game pads. However, it does not currently have a definition specifically for assistive technology input devices. So, assistive technology products must still emulate one of the defined devices (such as a keyboard or mouse) to provide the specialized input. There are no general standards defined to do this for assistive technology developers to fol- low, which has resulted in different manufacturers using the USB HID in different ways. This has resulted in incompat- ibilities between assistive technology products and confu- sion for the end users. The development of an assistive technology definition for the USB HID standard has been proposed to address the issue of incompatibility. There are no general standards for assistive technology applications, and different manufacturers implement the HID standard in different ways. The development of an assistive technol- ogy definition for the USB standard has been proposed to address the issue of incompatibility (Marsden, 2005).

Emulating interfaces have a general set of characteristics that allow the computer to be altered for a given application and for a specific person with a disability. Commercial prod- ucts may be implemented with features that include some or all of these general characteristics, and specific commercial features can change rapidly. The characteristics of an emulat- ing interface are customized through a setup, a concept that originated with the adaptive firmware card (AFC) for the Apple II series of computers (Schwejda and Vanderheiden, 1982). As shown in Box 7-1, a setup consists of three basic elements: (1) an input method, (2) overlays, and (3) a set of options. The features of the setup may be implemented in hardware (electronic circuits) or software (a program) or both. Storage of a setup may be in memory within the emu- lator hardware or resident in the computer memory. Setups are also usually stored on the computer hard disk drive or in the peripheral device (e.g., an alternative keyboard), which allows them to be loaded into the computer or the emulator as needed. As shown in Box 7-1, the setup is used with an application program.

Several examples of setups that may be used with differ- ent application programs are shown in Figure 7-3. The setup shown in Figure 7-3, A, is intended to be used for text entry

218 C H A P T E R 7 Human/Assistive Technology Interface

P A R T III The Activities: General Purpose Assistive Technologies 219

BOX 7-1

A setup consists of the following three parts: 1. Input method

Keyboard: ● Assisted ● Contracted ● Expanded ● Virtual ● Normal Morse code: ● One switch ● Two switch ASCII*: ● Parallel ● Serial Scanning: ● Linear or row-column ● Auto, inverse, or step ● Single-, dual-, four-, or five switch ● Switched joystick Proportional: ● Mouse ● Trackball ● Joystick

2. Overlay: all three of the following may be the same or they may be different

User: the selection set arrangement from which the user chooses

Computer: the character or string of characters sent to the application program when the user chooses

Speech: synthetic speech used as a prompt to the user or as feedback when a selection is made

3. Options Abbreviations: text-based codes Autocaps: CAP and 2 spaces after., !, or ? Key repeat rate Levels: like a shift, can be many levels on one setup;

equivalent in scanning is branching Macros: codes can include control characters and

functions Mouse emulation: move, drag, click, and tab Multitasking: can interrupt one mode for another Predictive entry: previous characters determine user

overlay Rate: how fast or slow the user can input to the GIDEI Screen selection display location: where on the screen the

user overlay appears Slowdown of programs Application program or disk: The business, education, or recreational program being used

*Sometimes used with AAC, environmental control units, or powered wheelchair controllers (see text).

Major Features of Commonly Used General Input Device-Emulating Interfaces

Method

Virtual keyboard

Speed of mouse

•

•

Business, productivity software (word

processing, spreadsheet, etc.)

Expanded keyboard

Speech Slowdown

• •

Early education matching task

with arrow and return

User: QWERTY Layout

Computer: Same

Speech: No

Single-switch scanning

Rate

•

•

Single-switch scanning

Rate Speech

Slowdown

User: ETA Array

Computer: Same

Speech: No

User:

Computer: Arrow, Return Speech: “This one,” “Next one”

User:

Computer: Arrow, Return Speech: “This one,” “Next one”

Overlay Options Application

STOP

OK

A

B

C

D

Figure 7-3 A GIDEI setup consists of three parts: input method, overlay, and options. A to D, Four examples of GIDEI setups for different consumers and different applications are shown.

in a business environment. The application software can be a word processor, a spreadsheet, or a database. The major function is the entry of text characters, and the setup includes several options to make this process more efficient. Autocapitalization automatically enters one space and latches the shift function after sentence-ending punctuation (i.e., .?!). Abbreviations allow a few characters to be used as a code for a longer word or phrase. The user of the emulator stores both the sequence of characters and their correspon- ding abbreviation. When the abbreviation (code) is entered, the emulator automatically expands it into the whole stored word or phrase. For example, typing the two letters MN (for “my name”) followed by an abbreviation key would result in the user’s name and address being entered. Several methods of abbreviation expansion and other types of rate enhance- ment are discussed in Chapter 11. The setup also includes macros, which are codes similar to abbreviations. The macros differ, however, in that they are often used to control appli- cation program functions. For example, assume that the word processor requires that the following keys be pressed to set a margin (such as for typing an address on an envelope): SHIFT F8 (shifted function key number 8) 174 ENTER, a total of 6 keystrokes (if SHIFT and F8 are pressed in sequence). A macro for this key sequence could be defined as [ALT]E. This would save four keystrokes (if the ALT key and E were pressed in sequence), and it would also be easier to remember these two keys than the entire key sequence. It is also possible to store mouse functions and “replay” them with one command. Another way to save keystrokes is for the computer to anticipate the words on the basis of previ- ous characters entered. For example, if a T is typed, then an H is very likely to follow. Likewise, it is possible to predict whole words rather than just letters. This method of input acceleration is called word prediction or word completion. In some cases the emulator software program keeps track of the words that the user inputs most frequently, and the choices presented is in the order of frequency of use for the specific person using the emulator. We discuss word prediction fur- ther later in this chapter. Many of these options are available for both the Windows (see www.microsoft.com/enable/ default.aspx) and Macintosh (see http://www.apple.com/ accessibility/ ) operating systems. Additional information is also available from the manufacturers’ Web sites listed here.

This set of options can be used with any of the input methods shown in Box 7-1. The particular input method determines the overlays. The term on-screen keyboard refers to those keyboard emulation methods that use a video image of the keyboard on the video screen, together with a cursor. An example is shown in Figure 7-3, A. The display of the keyboard layout on the screen can contain key locations for use as macros and it can be arranged to make selections as fast as possible. For a single-switch user, the overlay on the screen may be a scanning array with special characters included, as shown in Figure 7-3, B.

A second setup, shown in Figure 7-3, C and D, is for a young child who is using any of a wide range of software programs that require selection of an answer by matching a cursor (pointer) location with the correct item (Figure 7-4). The task may be to match numbers, letters, shapes, words, or pictures. Often the software requires that one key (e.g., RIGHT ARROW) be used to move the cursor and another key (e.g., RETURN) to select the one that the stu- dent believes is correct. Two setups are shown in Figure 7-3 for this application. In this case the user and computer over- lays are different, so a speech overlay is also included. Because the user is not likely to have learned to read yet, the speech overlay helps identify the choices to be made. Speech is used as a reinforcer when the choice is made, which is shown as a second speech overlay in Figure 7-3, C. This setup is for use with an expanded keyboard. In this case a visual overlay with symbols can be used. An example is shown in Figure 7-5. Another overlay, Figure 7-3, D, shows the use of scanning on the screen, which is restricted to text characters. For example, an arrow can be generated with two dashes and the greater than (>) sign. “OK” is used as the label for “this is the one I want” (the student’s choice). Both these setups use the speech, scanning rate, and program slow- down options. However, for the second setup (scanning), an option that allows us to place the scanning array on any line of the display monitor is also included. This option is important because the scan line can hide part of the pro- gram if it is in a fixed location.

Many USB-based input devices allow other features, such as mouse emulation and the use of macro instructions and multitasking. Mouse emulation substitutes a set of keys, a scanning array, or Morse code characters for mouse functions (similar to MouseKeys, Table 7-1). Macros can be used to return the mouse cursor to a specific location on the basis of stored information. This feature can save time when

220 C H A P T E R 7 Human/Assistive Technology Interface

Figure 7-4 A GIDEI overlay for cursor-controlling movement by using arrows. This is being used with an expanded keyboard and an educational software program.

scanning is the mode used for mouse emulation. All these features can be incorporated into a setup that can be loaded when it is necessary or desirable to use the mouse. Anson (1997) describes the characteristics of several GIDEIs for both Windows and Macintosh operating systems.

All currently available commercial devices use the USB standard for providing adapted input, and they are designed for either, or both, Windows-based and Macintosh computers. All adapted input devices have a hardware component, and some have software that may be used for operation or cus- tomization. All also have provisions for attachment of con- trol interfaces (alternative keyboards, switches, etc.).

Many of the adapted inputs listed in Table 7-2 include keyboard or mouse emulation. Some of these systems may also require a software program to be loaded into the host computer. This software may be used as part of the emula- tion process, and it also supports specialized setups for the adapted input device to be used with specific software pro- grams (e.g., the educational applications described in Chapter 15).

General-Purpose Emulators. The first general- purpose keyboard emulator to be widely available was the AFC. The original version of this device was intended for use in the Apple II+ computer (Schwejda and Vanderheiden, 1982). The features incorporated in the AFC are still fundamental to most current emulators. In a very real sense, virtually all the basic capabilities have their origins in the AFC. The major advances in emulator design

have been the result of advances in the host computer rather than fundamental insights into the process of keyboard and mouse emulation.

Emulators also use built-in synthetic speech feedback in “talking setups” that allow the user to receive auditory and visual prompting and feedback. This feature is useful for young children who may not be able to read, for visually impaired individuals, and as an added input modality for persons with learning disabilities.

The Kenx was originally designed to provide alternative input to the Macintosh computer and was later ported to the Windows operating system as well. It was originally pack- aged as a combination of hardware and software that incor- porated scanning, Morse code, alternative keyboard, and on-screen keyboard functions. The software became known as “Discover.” Today’s software, called DiscoverPro (Madentec, Ltd, Edmonton, Alberta, Canada; www. Madentec.com), works with a number of alternative input devices, including IntelliKeys (IntelliTools, Petaluma, Calif.; www.intellitools.com), IntelliSwitch (Madentec, Ltd), and head pointers such as TrackerPro (Madentec, Ltd), or HeadMouse (Origin Instruments, Grand Prairie, Tex.; www.orin.com).

P A R T III The Activities: General Purpose Assistive Technologies 221

Figure 7-5 A symbol-based GIDEI overlay for use with an expanded keyboard and an educational software program.

Minimal Adaptations to the Standard Keyboard and Mouse*

Need Addressed Software Approach

Modifier key cannot be used StickyKeys†

at same time as another key User cannot release key before FilterKeys†

it starts to repeat User accidentally hits wrong keys SlowKeys,† BounceKeys,†

FilterKeys†

User cannot manipulate mouse MouseKeys†

User wants to use augmentative SerialKeys† in Windows XP or communication device as input an alternative (like AAC keys)

User cannot access keyboard On-screen keyboard (Windows Vista) (Windows XP and Vista)

Built-in ASR

*Easy Access (part of universal access) in Macintosh operating system, Apple Computer, Cupertino, Calif.; accessibility options in Windows XP, Ease of Access in Windows Vista, Microsoft Corp., Seattle, Wash. †Software modifications developed at the Trace Center, University of Wisconsin, Madison. These are included as before-market modifications to the Macintosh operating system or Windows in some personal computers and are available as after-market versions in others. The function of each program is as follows: StickyKeys: user can press modifier key, then press second key without

holding both down simultaneously. SlowKeys: a delay can be added before the character selected by hitting a

key is entered into the computer; this means that the user can release an incorrect key before it is entered.

BounceKeys: prevents double characters from being entered if the user bounces on the key when pressing and releasing.

FilterKeys: the combination of SlowKeys, BounceKeys, and RepeatKeys in Microsoft Windows.

MouseKeys: substitutes arrow keys for mouse movements. SerialKeys: allows any serial input to replace mouse and keyboard; this

function has largely been replaced by USB standard devices.

TABLE 7-1

Discover can either be enabled at startup (when the power is turned on) or activated by clicking on the Discover icon once the computer has booted. Some of the most useful fea- tures of Discover are those that are specifically aimed at the graphical user interface (GUI). It is possible with Discover, for example, to set tabs on the screen where the mouse is to point and then store the tab as a code (or macro). When the code is entered (by use of any of the basic selection methods and control interfaces), the mouse carries out the movement stored. By saving a series of mouse move- ments, it is possible to move to a menu, open it, select a spe- cific entry, and then double-click (to start execution), all with one command. This not only saves many mouse move- ments, but it also avoids errors during tedious and complex movements. If a particular target software application has keyboard-equivalent commands to perform its functions, those can also be issued directly by Discover. Discover also provides row-column scanning with visually enhanced scan- ning arrays and audible cues, making it useful for people with multiple disabilities (such as blindness and motor impairments). Other useful features include digitized speech, on-screen keyboards, “invisible” setups (for issuing commands without an on-screen keyboard appearing), and

development and printing of keyboard overlays for use with expanded keyboards.

The DARCI TOO provides for alternative mouse, alter- native keyboard, joystick, and switch input to Windows- based and Macintosh computers. Input to the computer is through the serial port and it conforms to the Trace standard for GIDEI design. Both a hardware component for attach- ing the external device to the computer and software to accept that input are included. Two versions of the DARCI TOO are available. One uses an external hardware box that connects to a serial port on the computer. Five operating modes are available with the DARCI TOO: scanning, Morse code, DARCI code matrix keyboard, and communi- cation device. The DARCI USB supports Morse code alter- native input through the USB port. No additional software is required, but the MouseKeys accessibility feature must be activated for use.

The process by which a computer can be adapted by use of a software program is described by Hortsman, Levine, and Jaros (1989). Programs in this category range from those implementing the basic features of Table 7-1 to the use of alternate control interfaces and selection methods (Gorgens, Bergler, and Gorgens, 1990). The programs

222 C H A P T E R 7 Human/Assistive Technology Interface

Alternative Keyboards for Direct Selection

Category Description Device Name/Manufacturer

Expanded keyboards Generally membrane keyboards that have enlarged target IntelliKeys (IntelliTools); USB King Keyboard areas, often programmable so that key size can be (TASH, Inc.); Expanded Keyboard (EKEG customized; useful for individuals with good range and Electronics Company, LTD); Big Keys Plus poor resolution; also useful for individuals with limited (Inclusive Technologies); Touch and Go and cognitive/language skills or visual impairment. Concept Keyboard (Traxsys Computer

Products); Expanded Keyboard (Maltron) Contracted keyboards Miniature, full-function keyboards, typically with membrane USB Mini Keyboard (TASH, Inc.); Mini Keyboard

overlay; useful for individuals with limited range of (EKEG Electronics Co. Ltd.); The Magic Wand motion and good resolution. Keyboard (In Touch Systems)

Touch screens/touch Activated by either breaking a very thin light beam or by a Touch Window (RiverDeep); MagicTouch tablets capacitive array that detects the electrical charge on the (Laureate Learning Systems, Inc.)

finger; the electrode array used to detect where the finger or pointer is touching is transparent; touch screen can be placed over the face of a monitor.

TongueTouch Keypad Battery-operated, radio frequency–transmitting device with UCS 2000 with TongueTouch Keypad nine pressure-sensitive keys activated by tongue; (newAbilities, Inc.) universal controller processes information sent from keypad to receiver.

Special-purpose Keyboards on special-purpose devices, such as augmentative See Chapter 11 keyboards communication and environmental control devices;

available keys may be much more limited in number or may be specific in function compared with standard keyboard.

Data from RiverDeep, San Francisco, Calif. (http://rivapprod2.riverdeep.net/); EKEG Electronics, Vancouver, Canada (http://www.ekegelectronics.com/); Laureate Learning Systems, Inc. Winooski, Vt. (www.laureatelearning.com); newAbilities, Inc., Palo Alto, Calif. (www.newabilities.com); IntelliTools, Petaluma, Calif. (www. intellitools.com); Inclusive Technologies (http://www.inclusive.co.uk/catalogue/index.html); In Touch Systems, Spring Valley, N.Y. (www.magicwandkeyboard.com); Maltron-USA (http://www.maltron-usa.com/expanded.htm); Traxsys Computer Products (http://assistive.traxsys.com/staticProductListing.asp); TASH, Ajax, Ontario, Canada, or Richmond, Va. (www.tashinc.com).

TABLE 7-2

described by these authors and others provide access to Windows and/or Macintosh operating systems. Anson (1997) describes these and other approaches.

On-Screen Selection Sets. On-screen selection sets use mouse (point-and-click) approaches or scanning to make selections. The keyboard image, shown in Figure 7-6, B, is

divided into “keys,” each of which is labeled with an alphanumerical character, special character, or function. All the possible keys on the computer keyboard being emu- lated are included in the on-screen keyboard display. The emulation software places the keyboard or scanning array image on the screen, detects the mouse or scanning cursor position, relates the position to the key label of the on-screen

P A R T III The Activities: General Purpose Assistive Technologies 223

A

B

Word Completion Dragger Toolbar

Right Drag

Right Click Left Double Click

Left Drag

Hide/Show Keyboard

AutoClick Rest

Toolbar Orientation

Quit

Move Top/Bottom

Hide Menu

Figure 7-6 A, Head-controlled mouse. B, An example of an on-screen keyboard screen for Microsoft Windows. (Courtesy Origin Instruments Corporation, www.orin.com.)

keyboard image, and inserts that character into the keyboard routine of the computer so that it is treated as a typed char- acter. Windows also includes a basic on-screen keyboard in its accessibility options. To enter a character or select a function, the user of the on-screen keyboard positions the cursor inside the desired “key” on the screen. Movement of the cursor can be by mouse, trackball, joystick, switch array, or head-controlled mouse. Once the cursor is located inside the targeted key, the user makes the selection either by acti- vating another switch or by holding the cursor on the choice until the device accepts it. Various types of on-screen key- boards allow changes in the keyboard arrangement, size of the on-screen keys, location of the keyboard on the screen, and methods by which this customization can be accom- plished. Many of the on-screen keyboard systems also include other characteristics. One of the most common is a word prediction feature that displays frequently used words as the first few characters are typed. Each word may be in a key location or on a list presented in a window. This type of input acceleration is discussed in more detail in Chapter 11. Other features that can be used to optimize performance include horizontal and vertical cursor movement speed, key- board layouts, and location of the keyboard image on the screen (e.g., top or bottom, depending on the type of appli- cation program that is running). Anson (1997) describes several commercial approaches to both hardware and soft- ware for on-screen keyboards.

Shein et al (1991) describe the challenges and the approaches that solve some of the problems in the develop- ment of emulators for Windows. They indicate that any visual keyboard in a GUI should have several features. First, selecting keys (e.g., with an on-screen keyboard and head pointer) from the visual keyboard should not transfer the internal computer keyboard routines to the new selection but should keep the computer looking for input from the visual keyboard. Typically, the most recently opened window is “on top” of the others. If the keyboard image is in a win- dow, then it must stay on top even if selections from it open another window. Second, the visual keyboard array should send keystroke input information to the application that is active at any given time. Finally, Shein et al state that the visual keyboard should support a range of layouts. These authors have developed one software-based emulator for the Windows and OS/2 GUIs. Several other commercially available products for Windows are available. These prod- ucts include a variety of input methods (on-screen keyboard with pointing device, scanning in several modes, Morse code), output options (voice synthesis, enlarged screen char- acters), and optional features (e.g., word prediction, commu- nication device pop-up windows, environmental control interfaces to telephone and appliances).

The use of more than one switch can enable other func- tions (Shein et al, 2003). In addition to directed scanning described earlier, these additional functions include a cancel

function when an incorrect entry is made, a faster scan to get to a region and then scan slowly through the region, reverse and forward scanning, and similar capabilities. Most on-screen keyboard or scanning arrays allow resizing of keys or selection elements, location of the on-screen display anywhere on the screen, word prediction, and abbreviation expansion.

Switch-Controlled Computer Keyboard and Mouse Emulation. When scanning is used for computer access, the scanning array resembles an on-screen keyboard, and it may occupy up to half of the screen. The result is that the user has two windows open, one for the scanning array and one for the application program. Additional hardware is required to accept from one to five switches as input. The scanning hardware plugs into the computer through a parallel, a serial, or a USB port. One or more of the scan- ning approaches described earlier may be used. Once a scan- ning choice is made, the on-screen keyboard software sends the proper code for the element (alphanumerical or special character) to the computer as if it has been typed. There are several general approaches to single-switch scanning for emulation of mouse functions (Blackstein-Alder et al, 2004). With cartesian scanning, a line moves slowly down the screen when the user presses the scanning switch. As it scrolls down the screen, the line intersects various on-screen icons. If the switch is pressed a second time, a pointer or ver- tical line moves across the screen. When the pointer or ver- tical line is located over the desired screen icon, a third switch press selects that icon as though the mouse button had been pressed. This function is similar to matrix-type row-column scanning except that the scan is continuous rather than moving discretely between choices.

A second general approach to scanning mouse emulation is cartesian also, but with discrete scanning between screen elements. This method more closely approximates typical row-column scanning. A third approach is rotational scan- ning that involves two steps, pointing toward a target and then moving the mouse pointer toward the target. When the user activates the switch once, a scan line is drawn from the center to the right-hand side of the computer screen. This scan line rotates about the center at a continuous speed coun- terclockwise around the screen. When the line intersects an on-screen target, the user activates the switch a second time to stop the rotational scanning. This line remains visible, and a second perpendicular line begins scanning outward from the center. When this line intersects the desired target, the user hits the switch a third time to make the selection.

Commercial programs also allow the user to select what mouse button function (click to select, double-click to open and run the application, or drag to move) is activated with the third switch press. In some cases the selected function is implemented only after an acceptance time. If an additional switch press occurs before the acceptance time (less than a

224 C H A P T E R 7 Human/Assistive Technology Interface

second, typically), the selection is cancelled, which allows for error correction before an entry is made.

Blackstein-Alder et al (2004) carried out a comparative study of mouse emulation scanning. They used the two types of cartesian scanning, rotational scanning, and a hybrid approach that scans quadrants of the screen and then scans within the quadrant (for example, ScanBuddy, Applied Human Factors, Helotes, Tex.; www.ahf-net.com). Their subjects were all individuals who had a physical disability with cerebral palsy or a related condition. The subjects were given an opportunity to practice with each of the four tech- niques before using them in a controlled exercise. The length of practice required varied widely among the subjects. Accuracy (number of correct target selected) was variable. About half the subjects had very similar results for all four methods. For the other half, there was more variability among the methods, with the hybrid approach generating the most errors. Three types of errors occurred: hitting too early (before the cursor reached the desired target), hitting too late, and double switch hits in quick succession (perse- veration), which cancelled the entry. Selection times for the two cartesian and hybrid approaches were very similar. Selection times for the rotational approach were more than twice as long as for the other three methods. The majority of users favored the discrete cartesian approach. Cartesian continuous was chosen as the favorite by a second group. None chose rotational scanning as the preferred method. Although not directly applicable to clinical applications because of the use of a simplified scanning program for data collection, these results do point out the value of practice and the difficulties in using a rotational approach. Scan times, scanning line width, dwell time before rest or selec- tion, and other characteristics are adjustable on most com- mercial products.

Another approach to mouse emulation is the creation of on screen “hot spots” in software applications (for example, ClickIT, Intellitools, Petaluma, Calif.; www.intellitools.com/ ). These are scanned sequentially. This approach optimizes the scan to only those parts of the GUI screen that are active during an application. The hot spot locations are defined by the user (or more typically a supporter of the user) and stored for a particular application. A variety of approaches (e.g., automatic, inverse, and step) can be used to scan the hot spots with one or two switches. Several com- mercial products provide for mouse functions during scan- ning (Dragger, Origin Instruments, Grand Prairie, Tex., www.orin.com; ScanBuddy, Applied Human Factors, Helotes, Tex., www.ahf-net.com). An example is shown in Figure 7-6, A. In general, these programs allow the user to select the mouse function after the selection of a target by using any of the scanning or hot spot approaches described here. A more generic approach is one in which all interface objects in Windows are scanned as hot spots until the scan is stopped by switch activation (WIVIK, WiVik; also

http://www.wivik.com/index.html). This action begins the next sequence (e.g., scanning down a list of choices in an opened menu).

The basic operating system allows the speed of mouse movement, the trail left by the mouse, and other features to be adjusted. For individuals with severe motor impairments, the built-in adjustment of mouse speed, cursor size, and so forth are not sufficient to allow use of the mouse or other pointing device. There are commercial products that extend the range of these adjustments and add other features such as wrapping the cursor around the screen when it reaches one side (i.e., when the cursor hits the right edge of the screen it appears again on the left side; for example, PointSmart, Infogrip, Ventura, Calif., www.inforgrip.com).

Single- or dual-switch computer users can also use coded access including Morse code and DARCI (WesTest Engineering, Farmington, Utah; www.westest.com) code. Because codes are typically memory based, they do not require a selection display (a set of characters on the screen), as is needed for an on-screen keyboard or scanning array. This method allows the entire screen to be used for the application software being run. When Samuel Morse invented his code in the late 1880s, there were no comput- ers, and therefore basic Morse code does not include ESC or RETURN keys on the computer or characters such as punc- tuation or \/@#$%. Even more important, Morse saw no need for a SPACE character. He just told his key operators to wait a little longer between dots and dashes (a dot [.] is a short sound and a dash [-] is a longer sound). Unfortunately, the computer requires that a specific ASCII character be sent for SPACE. The absence of standardized codes for anything other than alphanumerical characters (see Figure 7-25) pres- ents a problem with using Morse code for computer access. Examples of codes developed for computer use by several different manufacturers are listed in Table 7-3. Note that in some cases the codes for the same characters are different for the three systems and in other cases they are the same. This variation makes it difficult for the consumer to change from one communication device or adapted input device to another. Once the set of codes is learned and the motor patterns developed, it is very difficult to change to a new set of codes. Computer access with either scanning or Morse code can be accomplished by software programs, hardware adaptations, or combinations of both.

Communication Devices as Alternative Computer Inputs. Many augmentative communication devices (see Chapter 11) can also function as alternative keyboards for computer access. The communication device is connected to the computer through a serial or USB interface. This con- nection allows the communication device to send characters to the computer as if they were typed from the computer keyboard. Using the communication device has the advan- tage that the user has access to the same control interface

P A R T III The Activities: General Purpose Assistive Technologies 225

and selection technique for computer access as he or she uses for communication. This strategy reduces training and skill development time (e.g., no need to learn two keyboard layouts) and allows the user to concentrate on learning how to operate the computer. Another advantage is that any vocabulary (e.g., words or phrases or complete computer commands) stored in the communication device can be sent from the communication device to the computer as a whole by using a serial port. In many currently available communication devices, computer control is a built-in feature. In others it must be added as an option. Accessibility options (Windows) and universal access (Macintosh) pro- vide for input from the communication device with serial keys (see Table 7-1). A standard has been developed to allow all keyboard characters to be sent to the computer, even if the communication device does not have that character. For example, computer keys such as DEL may not be on the communication device, but the user can send a sequence of characters that the computer interprets as the DEL key. Selection of a special-purpose keyboard for a consumer also requires careful consideration of the items presented in Box 7-2.

There are, however, some disadvantages to this approach. One of these is that in many cases the communication device needs to be physically connected to the computer; that is, a cable must be physically plugged in to the com- puter. An alternative approach is to use wireless links to replace the cable. Most wireless systems use infrared (IR) links, which are similar to the IR environmental control links described in Chapter 14.

A second potential problem is that most communication devices are not able to generate all the possible ASCII codes needed for general-purpose computer access. For this rea- son, a special standard has been developed for establishing interaction between the computer and the communication device. Table 7-4 lists examples of the character strings used in this standard. All these codes begin with the ESC (escape) code and end with a period (.), and they are intended to be transmitted over a cable to the computer serial port. Unfortunately, not all currently available commu- nication devices support this standard, and it may be neces- sary for the assistive technology practitioner (ATP) to program the communication device manually to allow use of the computer. For example, one square on a communication device may have the sequence of characters “[ESC]ret.” stored; when this square is selected, the computer responds as though the RETURN key has been pressed. These char- acters must be programmed into the communication device, together with the other sequences in Table 7-4.

226 C H A P T E R 7 Human/Assistive Technology Interface

Nonstandardized Morse Codes Used for Computer Access

Character Kenx* Darci Too†

ESC - - -. ..-.. ENTER .-.- .-.- DELETE ..- -.. -..-. TAB -.-..- -.- -. . .-.-.- .-.-.- ! .-..- .-..- - $ .-.-. -...-. SPACE ..- - ..- - , - -..- - - -..- - “. -.- - - -.- - ( ..- -. ...- -. ) ..-.- -.. - -. UP ARROW - -.- - - ---.. DOWN ARROW - -..- ------ LEFT ARROW - - - - -----. RIGHT ARROW ..-..- - -.-.-. SHIFT ....-. ..-.-

Note: Standard alphanumerical Morse code characters are shown in Figure 7-25. *Kenx, Madentec, Edmonton, Alberta, Canada. †Darci Too for Windows-based computers, WesTest Engineering, Bountiful, Utah.

TABLE 7-3 BOX 7-2 Critical Questions for Evaluating Keyboard Use

1. Can the consumer reach all the keys on the keyboard? 2. Are the size, spacing, and sensory feedback of the keys

appropriate? 3. Is the consumer’s speed of input adequate for the task? 4. Does the consumer target keys with approximately 75%

accuracy? 5. Is the consumer able to simultaneously hold down the

modifier key and select another key? 6. Is the consumer able to control the duration for which a

key must be pressed before it repeats itself? 7. Does the consumer effectively use the standard keyboard

layout?

CASE STUDY

AUGMENTATIVE AND ALTERNATIVE COMMUNICATION AS A COMPUTER INPUT

You are working with a teenager who has an augmenta- tive and alternative communication (AAC) device that she uses very well (see Chapter 11). She has come to the ATP for development of computer access for writing in school. Which of the accessibility options should the ATP use to interface with her AAC device? What questions should be asked about her AAC device, and what capabilities would it need to have to be functional in this application? What character strings would need to be available in the AAC device for her to be able to input the RETURN, ALT, and SHIFT characters in her word processing program?

According to Table 7-4, to cause a TAB key to be entered, an input device that adheres to the Trace standard looks for the five-character string [ESC]TAB., and when it is received, the program running on the computer reacts as if the TAB key has been pressed by itself from the keyboard. For example, pressing the TAB key in a word processing program moves the cursor five spaces to the right. Another example from Table 7-4 is the entry of a function key. The Trace standard uses the four characters [ESC]F1. as the character string for function key number 1. When this string is sent from the communication device, the computer acts as if the key F1 has been pressed from the keyboard. In many programs, entering this key results in a help menu, and the character string has the same effect as pressing the F1 key.

CHARACTERISTICS OF CONTROL INTERFACES

Before the specific types of control interfaces and the selection of a control interface for the user is discussed, it is necessary

to have an understanding of their characteristics. Controls differ according to their spatial, sensory, and activation char- acteristics (Barker and Cook, 1981). When a control inter- face is selected for an individual, these characteristics should be taken into consideration. The placement and size of the control interface (spatial characteristics), how it is activated (activation characteristics), and what feedback is obtained as a result of its activation (sensory characteristics) should be considered.

Spatial Characteristics

The spatial characteristics of a control interface are (1) its overall physical size (dimensions), shape, and weight, (2) the number of available targets contained within the control interface, (3) the size of each target, and (4) the spacing between targets. Control interfaces can be grouped into broad categories on the basis of their spatial character- istics. For example, a single switch has one target, and the target size is the dimension (height and width) of the switch. Typically, a single switch can accommodate an indi- vidual who has limitations in range and only gross resolution for activation. Switch arrays (including joysticks) have two to five switches, each representing a different target. The user’s range required to access a switch array needs to be larger than for a single switch but still be relatively small, depending on the spacing between the switches. The user’s resolution needs to be more refined than that required for a single switch and less refined than that for a keyboard. A contracted keyboard has keys (targets) of small size in close proximity to each other. Its overall size is also small. The keys on these keyboards range in size from 0.5 to 1.5 cm, and they require relatively fine resolution from the user. The requirement for the user’s range is moderate (less than 15 cm in both horizontal and vertical directions). Standard or commonly used keyboards require moderate range and relatively fine resolution of the user. Finally, expanded keyboards have large overall size and enlarged tar- get size, requiring relatively large range and fine resolution. Switch arrays and keyboards can have from two to more than 100 targets.

Activation and Deactivation Characteristics

Many characteristics are related to the activation of the con- trol interface. The activation characteristics of a control interface consist of the method of activation, effort, dis- placement, flexibility, and durability and maintainability. Deactivation, or the release, of a control interface is another characteristic that needs to be considered.

Method of Activation. The method of activation is the way in which a signal sent by the user is detected by the con- trol interface and activates the processor. Table 7-5 shows the methods of activation. The first column identifies the

P A R T III The Activities: General Purpose Assistive Technologies 227

Trace Standard for Computer Input by Augmentative Communication Systems and Other GIDEIs

Key Designation ESC Sequence Computer

DEL [ESC]del. A DELETE [ESC]delete. I, M CONTROL [ESC]control. All DOWN ARROW [ESC]down. All LEFT ARROW [ESC]left. All ENTER [ESC]enter. M, I RETURN [ESC]ret. A, M TAB [ESC]tab. All BACKSPACE [ESC]backspace. I, M SHIFT [ESC]shift. A, I, M* ALTERNATE [ESC]alt. I* CONTROL [ESC]ctrl. A, I,* M* ESCAPE [ESC]esc. All RESET [ESC]reset. A FUNCTION + # [ESC]f# I† INSERT [ESC]insert. I HOME [ESC]home. I END [ESC]end. I PAGE UP [ESC]pageup. I, M PAGE DOWN [ESC]pagedown. I, M KEYPAD [ESC]keypad. I, M‡

SCROLL [ESC]scroll. I, M PRINT SCREEN [ESC]print. I OPTION [ESC]option. A, M

A, Apple II series; M, Apple Macintosh; I, Windows PC. *Some computers have both left and right shift, control, or alternate keys; use left or right key. For example, LEFT SHIFT = [ESC]lshift., RIGHT ALT = [ESC]ralt., LEFT CONTROL = [ESC]rctrl. †This sequence is used for each function key, with the key number substituted for the # sign; for example, function key 1 = [ESC]f1. ‡On Macintosh and Windows PCs, the keypad keys are all preceded by kp; for example, 7 on keypad = [ESC]kp7.

TABLE 7-4

three ways the user can send a signal to the control interface: movement, respiration, and phonation; the middle column shows how each of these signals is detected by the control interface; and the column on the far right provides examples of each type of control interface.

Movements by the user can be detected by the control interface in three basic ways. The movement may generate a force, external to the body, that is detected by the control interface. These are mechanical control interfaces, and they represent the largest category of control interfaces. Most switches, keyboard keys, joysticks, and other controls that require movement or force for activation (e.g., mouse, track- ball) fall into this category. Force is always required to acti- vate a mechanical control interface; however, mechanical displacement may or may not occur. For example, force- controlled joysticks and membrane keyboards have very little displacement when activated. Electromagnetic control interfaces do not require contact from the user’s body for activation. They detect movement at a distance through either light or radio frequency energy. Examples include head-mounted light sources or detectors and transmitters used with EADLs for remote control (similar to garage door openers). Another example of an electromagnetic control interface is the use of a light beam in a manner similar to the system in many retail stores in which a customer interrupts a light beam when entering or leaving the store. Electrical control interfaces are sensitive to electrical currents generated by the body. One type, called a capacitive switch, detects static elec- tricity on the surface of the body. This is similar to the game children play when they attempt to shock someone with static electricity. A common example of this type of interface is seen in some elevator buttons. The switches require no force, and they are therefore useful to individuals who have muscle weakness. Other electrical control interfaces use electrodes attached to the skin to detect underlying muscle electrical activity. The electromyographic (EMG) signal

associated with muscle contraction is the most commonly used signal. Electrodes placed near the eyes can measure eye movements and generate an electro-oculographic (EOG) signal based on eye movements. Proximity control interfaces, the last type of interface that detects movement, are also active at a distance, but they detect heat or other signals without coming into contact with the body. Although infre- quently used, body heat sensors have been successful as con- trol interfaces when force cannot be generated. In summary, mechanical and electrical switches both require contact with the body, and mechanical types also require the generation of force. Electromagnetic and proximity switches do not require contact with the body.

The second type of body-generated signal shown in Table 7-5 is respiration. The signal detected is either air flow or air pressure. The use of this type of control interface, gen- erally called a sip-and-puff switch, requires that the user be able to place and maintain the lips around a tube and produce good control of air flow. When sound or speech is produced by the air flow, we call it phonation (see Chapter 3). This is a method of activation that has developed rapidly over the last few years with speech recognition interfaces. Individuals who have physical involvement that makes other means of activating a control interface difficult may be able to produce sounds, letters, or words consistently enough to activate a control interface.

Effort. The effort required by the user to generate the sig- nal from the control interface is the next activation charac- teristic to consider. Activation effort varies from zero upward to a relatively large amount. For a mechanical inter- face, this is the force required to cause switch activation. For an electromagnetic interface, the effort is the minimal distance of movement sufficient to cause activation of the sensors. For example, an individual using a light pointer to choose from an array of different items must have sufficient

228 C H A P T E R 7 Human/Assistive Technology Interface

Method of Activation

Signal Sent, User Action (What the Body Does) Signal Detected Examples

1. Movement (eye, head, 1a. Mechanical control interface: activation by the application 1a. Joystick, keyboard, tread switch tongue, arms, legs) of a force

1b. Electromagnetic control interface: activation by the receipt 1b. Light pointer, light detector, of electromagnetic energy such as light or radio waves remote radio transmitter

1c. Electrical control interface: activation by detection of 1c. EMG, EOG, capacitive, or electrical signals from the surface of the body contact switch

1d. Proximity control interface: activation by a movement 1d. Heat-sensitive switches close to the detector but without contact

2. Respiration (inhalation- 2. Pneumatic control interface: activation by detection of 2. Puff and sip expiration) respiratory airflow or pressure

3. Phonation 3. Sound or voice control interface: activation by the detection 3. Sound switch, whistle switch, of articulated sounds or speech speech recognition

TABLE 7-5

head movement (the effort) to move the light beam from one element (represented by a sensor) to another element (which has a different sensor) and enough stability to hold the light beam on that element. Electrical interfaces require a range of effort from zero (for a capacitive switch) to rela- tively high for muscle force activation of an EMG. The EMG is measured by electrodes placed on the surface of the skin. The magnitude of the electrical signal is proportional to the amount of force generated by the muscle (the effort). Depending on the muscle and the sensitivity of the meas- urement system, the effort can vary from a small force to a large force. The level of effort for proximity switches is the distance of movement required for activation. An example is waving a hand close to a heat-sensitive switch. The activa- tion effort of pneumatic control interfaces is the amount of exhalation or inhalation required for activation, which can be either how hard (pressure) or how fast (flow) air is exhaled or inhaled. For example, some power wheelchair processors use a system in which a hard puff (large effort and high pres- sure generated) is forward, a soft puff (small effort and low pressure generated) is a right turn, a hard sip is reverse, and a soft sip is a left turn. The difference in these control signals is based primarily on effort generated. Phonation signals also have a level of effort related (at the simplest control interface level) to volume or loudness. Noise-activated or sound-activated switches are similar to those found on some toys. For speech recognition control interfaces, the effort also includes proper pronunciation because the detection is based on identification of a particular word (see the section on speech recognition later in this chapter).

Displacement. Another characteristic that needs to be considered apart from effort is displacement. Displacement, which is defined as how far a control interface travels from its original position to its activated position, is unique to mechanical control interfaces. Some mechanical interfaces, such as a force-activated joystick, respond to force and require no displacement (Spaeth and Cooper, 1999). In this case the amount of force that the user exerts determines the output of the joystick. If more force is exerted, the output is greater. Because force is detected, rather than amount of travel or displacement of the joystick, the demands placed on the user change. For individuals who can exert a force over a small distance, this type of joystick is ideal. It also provides more tactile feedback to the user. Many mechani- cal control interfaces require movement and force for acti- vation. The displacement of these control interfaces provides kinesthetic (movement) feedback as well as tactile and propri- oceptive feedback (see Chapter 3). This increased amount of sensory feedback is often of benefit to the user. For example, membrane keyboards have very smaller displacement, and the forces to activate them are often smaller than for switches, which have greater displacement. Without the sensory feedback provided by the displacement, however,

users frequently press harder than necessary, thinking that more force is needed to activate the keys.

Deactivation. Although we have focused on the activa- tion of control interfaces, we need to keep in mind that there is also a force required to release, or deactivate, some control interfaces. Muscle contraction is necessary to remove, or release, the body part from the interface. Weiss (1990) meas- ured both activation and deactivation forces for several mechanical interfaces and found that force was required to release the control interface in all cases but that the deacti- vation force was approximately one third to one half that required for activation.

Flexibility. The flexibility of the control interface, or the number of ways in which it can be operated by a control site, also needs to be considered. There are many types of key- boards, joysticks, and switches and just as many ways in which the user can activate them. Among individuals with physical disabilities, wide differences in motor performance exist. Depending on the nature of the disability, an individ- ual may or may not have deficits in strength, range of motion, muscle tone, sensation, or coordination. For exam- ple, the quality of movement may be smooth or uncoordi- nated, reflex patterns may dominate movement or be absent, sensory deficits may or may not be present, muscle tone may be normal or increased or decreased, or there may be limita- tions in range of motion at any joint. Thus one person may push a key with a finger, another may use a thumb, and a third a head pointer. Control interfaces that allow for vari- ous ways of activation are considered to be flexible. In gen- eral, control interfaces that are activated by movement can typically be activated by several body sites and are consid- ered to be flexible in comparison to control interfaces that are limited to activation by respiration and phonation. Within the category of movement-activated controls, the flexibility varies, for example, from a lever switch, which is most commonly activated by head movement, to a tread switch, which is routinely used for activation by the foot, knee, hand, head, or chin. Some control interfaces, such as the touch switch, have an adjustment for the amount of effort required to activate them. This type of control can be useful for evaluation or for an individual who has fluctuating endurance or a degenerative condition.

The ways in which the control interface can be mounted or positioned for use also contribute to its flexibility. Mounting a control interface at the optimal position in the individual’s workspace facilitates activation. Some control interfaces, such as a computer mouse, are not intended for mounting and need to be used on a table or other flat sur- face, whereas other control interfaces, such as a joystick, can usually be mounted in a variety of locations and can there- fore be activated by the chin, hand, or foot. Mounting systems are discussed later in this chapter.

P A R T III The Activities: General Purpose Assistive Technologies 229

Durability and Maintainability. The durability of the control interface is a characteristic that needs consideration as well. Gathering information during the assessment regarding how often the interface is to be used and the amount of force that is to be generated on the interface by the user assists the ATP in making recommendations that correspond to the durability of the control interface. If the control interface is to be used by someone who exerts a great deal of pressure on it because of uncontrolled movements, it must be constructed so it can withstand this type of use. Switches and keyboards made out of plastic, for example, may not hold up well under these circumstances. In the long run it may be cost-effective to buy a more expensive inter- face made out of metal that will last longer.

A final consideration is the maintainability of the control interface. It is important to consider whether the interface can be easily cleaned and how it should be cleaned so as not to damage any components. Other considerations are whether any of its components need to be replaced periodi- cally and, if so, how difficult a procedure it is. For example, certain switches require a battery to operate, and when the battery dies, it must be replaced. It also helps to know who will be able to repair the control interface if it breaks down and, if it is in need of repair, whether there is a loaner avail- able for the consumer to use in the interim.

Sensory Characteristics

The auditory, somatosensory, and visual feedback produced during the activation of the control interface comprise its sensory characteristics. Some control interfaces provide auditory feedback in the form of a click when activated. For example, keyboards that use mechanical switches for each key usually click when pressed, thus providing auditory feedback. Other keyboards have a smooth membrane surface that does not provide any auditory feedback. Somatosensory feedback is the tactile, kinesthetic, or propri- oceptive response sensed on activation of the control inter- face. For example, the texture or “feel” of the activation surface provides tactile data. The position in space of the control site when the user activates the switch provides pro- prioceptive data. The data generated as a result of movement provide kinesthetic feedback to the user. When the interface is within the consumer’s visual field, visual data are obtained through observation of the placement and the movement of the control interface. For some individuals the type of visual data will mean the difference between successful and unsuc- cessful use of a control interface. For example, someone who has difficulty attending to objects in the environment may be more attentive to a switch that is large and bright red or yellow.

There is usually a direct relationship between the sensory data provided by the control interface and the amount of

effort required to activate it. A contact switch that is acti- vated by an electrical charge from the body (i.e., requiring only touch) does not provide the user with any somatosen- sory feedback. There is no force required and therefore little proprioceptive or visual feedback is provided. The contact switch is also silent, so auditory feedback is absent as well. In some instances we can alter the feedback generated by a control interface. For example, adding a beep to a contact switch provides auditory data or placing a distinguishing texture over the surface of a membrane keyboard provides feedback through the tactile system. Other switches, such as the tread, wobble, and rocker, provide abundant feedback in terms of having a certain feel to them (tactile), an observable movement of the mechanism (visual), and an audible click (auditory).

Generally, interfaces that provide rich sensory feedback facilitate performance. On occasion, sensory feedback may be detrimental to the user’s performance. For example, a control interface with an audible click may trigger a startle reflex in the user that interferes with motor movement. The user may eventually adjust to the sound and ignore it, but the ATP may want to consider an alternate control interface. The interrelationship of spatial, sensory, and activation characteristics of control interfaces plays an important role in the design of an assistive technology sys- tem. Each of these characteristics must be carefully consid- ered to make effective selections that meet the needs of the consumer.

Rate Enhancement

Rate enhancement refers to all approaches that result in the number of characters generated being greater than the number of selections the individual makes. For example using “ASAP[space]” for “As soon as possible.[space]” saves 16 keystrokes. Because an increased level of efficiency is obtained, the user has to make fewer entries and the overall rate is increased. Rate enhancement goals and approaches differ for direct selection and scanning. In direct selection the goal is to reduce the number of keystrokes while increas- ing the amount of information selected with each keystroke. In scanning the goal is to optimize the scanning array to reduce the time required to make a desired selection. Specific approaches are discussed later in this section. Rate enhancement is used for many electronic assistive technol- ogy applications, including augmentative communication (Chapter 11), computer access (this chapter), cell phone access, and electronic aids to daily living (Chapter 14). Many mainstream software applications use some form of rate enhancement, also called input acceleration. Effective rate enhancement requires that the motor task become auto- matic (Blackstone, 1990). Motor patterns become more automatic as they are practiced. As the skills improve, motor

230 C H A P T E R 7 Human/Assistive Technology Interface

and cognitive tasks become more automatic and the user becomes an “expert.” As Blackstone points out, once these motor patterns are established, even small changes in the task may result in dramatic decreases in rate.

Direct Selection Rate Enhancement. Rate enhance- ment techniques for direct selection fall into two broad categories: (1) encoding techniques and (2) prediction tech- niques. Vanderheiden and Lloyd (1986) distinguish three basic types of codes: memory based, chart based, and display based. These are compared in Table 7-6. A memory-based technique requires that both the user and his or her partner know the codes by memory or that the user has the codes memorized for entry into the device. Chart-based tech- niques have an index of the codes and their corresponding vocabulary items. This can be a simple paper list attached to an electronic device or a chart on the wall (e.g., two eye blinks equals “call nurse,” three eye blinks equals “please turn me,” eyes up equals “yes,” eyes down equals “no”). Figure 7-7 illustrates both a chart-based and a display-based approach for Morse code (Vanderheiden and Lloyd, 1986). In each device, two switches are used. The right switch produces dots and the left one produces dashes.

Abbreviation expansion is a technique in which a shortened form of a word or phrase (the abbreviation) stands for the entire word or phrase (the expansion). The abbreviations are automatically expanded by the device into the desired word or phrase. Beukelman and Yorkston (1984) evaluated five different coding strategies for abbre- viations: (1) random number, (2) alphabetical numerical, (3) numerical groupings with alphabetical codes, (4) alpha- betical with alphabetical word groupings, and (5) menu- based (similar to number 4, but provides prompting to the user after the category is entered). The third and fourth approaches included both a category (e.g., food) and an item in that category (e.g., banana). These coding strategies were found to be more effective (measured by accurate selections/minute) than either the numerical (worst per- formance) or alphabetical codes alone. The menu approach yielded midrange performance.

P A R T III The Activities: General Purpose Assistive Technologies 231

Modes (Memory, Chart, Display) of Presentation of Codes to the User

Type Memory Based Chart Based Display Based

Memory required Recall Recognition Recognition Advantages Can be used by those with visual Can be seen by both user Can be updated (dynamic display),

limitations and partner giving many stored items Disadvantages Limited to 200-300 items for Must have chart in visual field; Requires attention to display; can

most people chart can become separated slow down text selection because from device of split attention

TABLE 7-6

A

B

MORSE CODE DISPLAY AID

ERROR / RESET

Figure 7-7 Encoding systems may be either (A) chart based or (B) display based. (From Blackstone S: Augmentative communication, Rockville, MD, 1986, American Speech Language Hearing Association.)

Word prediction or word completion approaches use a window on the screen that displays an ordered list of the most likely words on the basis of the letters entered. In word completion, the user selects the desired word, if any, by enter- ing its code (e.g., a number listed next to the word) or contin- uing to enter letters if the desired word is not displayed (Figure 7-8) (see Case Study: Word Prediction Vocabularies). Word prediction devices offer a menu of words on the basis of previous words entered. (e.g., “computer” leads to list of “soft- ware,” “system,” “program,” “keyboard”). The most important advantage of this approach is the elimination of the need for memorizing codes. Word prediction (or completion) approaches require that the user redirect the gaze from the input (keyboard keys or scanning array) to a list of words after each entry to check for the presence of the desired word, which can reduce the item selection rate compared with letter-by-letter typing. This reduction in selection rate is due to “cognitive or perceptual load” that can offset the benefits achieved in keystroke savings and result in an overall decrease in text generation rate (Hortsman and Levine, 1996).

If the word lists are placed on the screen at the point in the document where the typed letters appear, then the user does not need to redirect his gaze to check the word list while typing. This approach can result in significantly fewer switch activations in scanning. One application of this approach, called Smart Lists (Applied Human Factors Helotes, Tex, www.ahf-net.com), can be used with either keyboard or scan- ning entry. Smart Keys (Applied Human Factors) is similar to the Minspeak icon prediction. After each entry only the keys that contain a prediction on the basis of that entry are left on the on-screen keyboard, which can make scanning significantly faster because only the relevant keys need to be scanned.

Predictive approaches may be fixed or adaptive. Fixed types have a stored word list that is based on frequency of use that never changes. This method is predictable and con- sistent for the user and can help in the development of motor and cognitive patterns for retrieval. Adaptive vocabu- laries change the ordering of words in the dictionary list by keeping track of the words used by the person. The words are always listed in frequency-of-use order. This approach is more directly matched to the user’s needs and recent usage.

Current technologies may include combinations of abbreviation expansion and word prediction. Abbreviations are more direct because the user can merely enter the code and immediately get the desired word, and this method allows complete phrases and sentences. Predictions are eas- ier to use because they do not require memorization of codes.

232 C H A P T E R 7 Human/Assistive Technology Interface

Figure 7-8 Word completion systems present a series of choices based on previous letters entered.

CASE STUDY

WORD PREDICTION VOCABULARIES

Assume that one college student is taking a course in assistive technologies and another student is taking a course in world religions. If both students have word completion/prediction systems, compare the word lists you might expect to be used for writing homework assignments for each course. Would most words be the same or different for the two applications? How would the word lists vary in (1) an adaptive system and (2) a nonadaptive system? What words would you start with as a basic vocabulary in each case?

These two techniques are actually very similar for fixed pre- dictive systems. For example, in Figure 7-8, the entry for “thinking” is the sequence thi4. This could be entered with- out having to look at the screen, and it would be equivalent to an abbreviation. These two approaches are compared in Table 7-7.

Scanning Rate Enhancement. Several rate enhance- ment approaches are possible in scanning (Lesher, Moulton, and Higginbotham, 1998). Optimization of the row-column matrix is based on placement of the most frequently used characters near the beginning so that they are scanned first. The matrix layout can also be rearranged by using predictive scanning in which word completion or prediction word lists are presented on the basis of previous scanning input. A computer simulation compared switch count (summation of the number of switch hits and the scan times) for seven text samples using each of the 14 techniques relative to a fixed array with the most frequently used characters at the begin- ning (baseline configuration) (Lesher, Moulton, and Higginbotham, 1998). In a fixed format matrix, placement of symbols (e.g., shift, backspace, and comma) rather than let- ters is the major factor contributing to switch savings. Changing the matrix with each input using a dynamic matrix rearrangement yielded the greatest average switch savings when the prediction was based on the previous four entries rather than fewer (e.g., two or three) previous entries (Lesher, Moulton, and Higginbotham, 1998). The greatest savings when using word and character lists in the scanning matrix was obtained when the list was presented first and then the matrix was scanned. All these results were based on computer modeling, and issues of motor and cognitive skills for persons who rely on AAC can dramatically affect these results (Horstman and Levine, 1996).

SELECTING CONTROL INTERFACES FOR THE USER

Selecting a control interface for an individual can be a com- plex process. Understanding the characteristics of control

interfaces as described above and following a systematic process to determine the user’s skills and evaluate the effec- tiveness of control interfaces can make this process easier. Figure 7-9 outlines a framework to guide the ATP through the decision-making process, ultimately leading to the selec- tion of a human/technology interface that matches the user’s needs and skills. On the basis of information acquired from

P A R T III The Activities: General Purpose Assistive Technologies 233

Comparison of Abbreviation Expansion and Word Completion

Method Abbreviation Expansion Word Completion Word Prediction

Memory required Recall Recognition Recognition Language skills Coding First letter spelling Reading Display type Memory based (chart for very small lists) Display based Display based Vocabulary Efficient for content words, greatest Adaptive or fixed, frequency of Words

rate enhancement for function words occurrence determined Flexibility User-determined abbreviations Different vocabularies for different Different vocabularies for

aid recall contexts different contexts

Word prediction and abbreviation expansion are display- and memory-based versions of the same approach.

TABLE 7-7

Outcomes of Needs Identification

1. What is the activity to be performed? 2. How many input signals are required by the activity? 3. Is there more than one activity/application to be carried out? 4. If more than one activity is being performed, is the same control interface adequate for both activities or does more than one control interface need to be considered?

Outcomes of Physical-Sensory Evaluation

1. Description of unique sensory needs (visual, auditory, tactile) 2. Identification of potential anatomical control sites 3. Determination of functional range of motion of control sites 4. Determination of resolution skills using control sites 5. Determination of potential benefit of the use of control enhancers

Control Enhancers

Modifications

Direct Selection

• Standard and alternative keyboards

• Standard and alternative pointing interfaces

• Voice recognition

Indirect Selection (Scanning, Directed Scanning, Coded Access)

• Switch arrays • Single switches

Figure 7-9 Framework for control interface decision making.

the needs identification and physical-sensory components of the evaluation process described in Chapter 4, the ATP makes a decision to pursue further evaluation on one of two paths: (1) interfaces for direct selection or (2) interfaces for indirect selection. In general, control interfaces for direct selection typically have greater numbers of targets and require more refined resolution skills. Control interfaces for indirect selection have eight or fewer targets and are more suitable for individuals with gross motor control. To make an informed decision regarding the most appropriate control interface for a user, the ATP needs to understand the alter- natives that are available and evaluate and compare the con- sumer’s ability to operate them. The following sections describe specific control interfaces for both direct and indi- rect selection and factors that influence the selection of one particular interface over another.

Applying the Outcomes of Needs Identification and Physical-Sensory Evaluations to Control Interface Selection

In Figure 7-9 we list specific information related to human/technology interface selection that is an outcome of the needs identification process. The information gathered reveals particular factors that should be considered during the interface selection process. For example, identifying the activity the consumer wants to perform provides us with information on how large an input domain is required and possible control interfaces to consider. If the consumer is in need of a power wheelchair and is not interested in using a computer, for example, it is not necessary to determine whether he or she can use a keyboard. Alternatively, the con- sumer may need to perform several functional activities (e.g., communication, mobility, and environmental control), which affects the selection of an interface. In situations such as this, it should be considered whether a different control interface for each function or a single integrated control for all the functions is to be used.

The information gathered during the physical-sensory skills evaluation gives us a profile of the user’s skills in these areas, specifically those shown in Figure 7-9. This informa- tion can be used to determine the acceptable parameters for potential control interfaces. The range measurement deter- mines the consumer’s minimal and maximal comfortable reach and defines the geometrical requirements for the indi- vidual’s workspace. This parameter provides an indication of the possible locations for placement of a control interface (or interfaces) and the maximal distance between the extreme outer edges of the interface (e.g., the overall size of a keyboard or switch array). The resolution measurement pro- vides data on the consumer’s ability to control his or her movement to select targets.

Given this information on the consumer’s skills, potential candidate control interfaces that have similar characteristics

in terms of the number and spacing of the targets and the size of individual switches or keys can be selected. Once can- didate interfaces have been selected, comparative testing is conducted.The purpose of comparative testing using the con- trol interfaces is to provide the ATP with information on how fast the consumer can input using the control interface and the accuracy of that input. Methods for carrying out compar- ative testing are described in Chapter 4. During comparative testing, it is also critical that the ATP gather subjective infor- mation from the consumer on each interface that is evaluated. This information includes the ease or difficulty of use.

Control Enhancers: Interface Positioning, Arm Supports, Mouthsticks, Head Pointers, and Hand Pointers

Control enhancers are aids and strategies that enhance or extend the physical control (range and resolution) a person

234 C H A P T E R 7 Human/Assistive Technology Interface

CASE STUDY

COMPARATIVE EVALUATION

Max is an 18-year-old man who has cerebral palsy. He lives in a residential facility and attends a work program through United Cerebral Palsy. Max has been referred to ABC Assistive Technology Center for a communication device. He currently communicates with others by using a manual communication board and eye blinks for yes and no.

Through evaluation of Max’s range and resolution, it has been determined that his best control sites are his right hand and his head. However, he does not have fine enough control at either site to use direct selection. The ATP decides to perform comparative interface testing by using a tread switch with Max’s hand and a lever switch at the side of his head. Data collected during the com- parative testing phase of the evaluation show that Max is more accurate and faster activating the switch with his head (versus his hand). However, Max has indicated a preference for using his hand instead of his head.

QUESTIONS

1. Given Max’s limited verbal communication, how would the ATP gather information from him regard- ing his opinion on the hand and the head switches?

2. What type of subjective information would the ATP want to gather from Max regarding his use of and preference for each of these two switches?

3. The data indicate that Max is faster and more accu- rate using the head switch. However, Max has indi- cated that he prefers the hand switch. What would the ATP’s recommendation be and why?

has available to use a control interface. In some cases a per- son’s control may be enhanced to the extent that he or she can select directly. In other cases control enhancers can min- imize fatigue. Control enhancers include strategies, such as varying the position or the characteristics of the control interface, and devices, such as mouthsticks, head and hand pointers, and arm supports.

The person and the control interface should both be positioned to maximize function. The importance of proper positioning to maximize an individual’s function is discussed in Chapter 6. A person’s position should be observed before and during the control interface evaluation. If inadequate positioning appears to be affecting the person’s ability to control an interface, it should be addressed before continu- ing with the evaluation. The position of the control interface can also affect the person’s ability to activate it. Changing the height or the angle of the control interface even slightly may enhance the person’s ability to control it.

As control interfaces become more sophisticated, control-enhancing features are becoming part of the interface. For example, certain joysticks have a feature called tremor dampening that allows adjustment of the joystick for people who have tremors. Tremor-dampening joysticks are able to distinguish between tremors, which are faster and smaller, and intentional movements, which are slower and larger. The joystick is adjusted so that the tremors are disregarded and only intentional movements are detected. This adjust- ment enhances the ability of an individual who might other- wise be unable to operate a joystick to control a power wheelchair. A similar feature, called filter keys, is used in Windows. When the filter keys feature is activated in Windows, brief keystrokes are ignored and the rate at which keys repeat when being pressed is delayed.

Individuals who have weakness in the arm may not have enough strength to access the full range of a keyboard ade- quately. A mobile arm support (Figure 7-10, A), which props the arm and assists in arm movements by eliminating some of the effects of gravity, may then allow the individual to access a keyboard. For the individual who has the gross motor abil- ity to move his or her arm and hand around a keyboard but has difficulty extending and isolating a finger to depress a key, a pointing aid may help.There are commercially available aids that can be strapped on to the hand to assist in pointing, such as the typing aid shown in Figure 7-10, B. In some cases it is necessary to custom fabricate a pointing aid for it to fit the consumer’s hand appropriately. These custom-fabricated aids can range from complex hand splints to simple tools such as a pencil with an enlarged eraser.

For individuals who lack functional movement in their arms and hands, a mouthstick or head pointer (Figure 7-11) can be used with head and neck movement to access a keyboard or perform other types of manipulation tasks (e.g., dialing a telephone number or turning pages in a book) (see Chapter 14). For a head pointer, a rod with a rubber tip

P A R T III The Activities: General Purpose Assistive Technologies 235

A

B

Figure 7-10 Control enhancers. A, Mobile arm support used to enhance the control in the upper extremity for accessing a control interface. B, Typing aid used to enhance a person’s ability to point and access a keyboard. (Courtesy Sammons Preston Co., Bolingbrook, Ill.)

B

A

Figure 7-11 Control enhancers. A, Mouthstick. B, Head pointer.

is attached to a band that is worn around the top of the head. The individual can then use the end of this rod to depress keys. Besides being able to move the head vertically and horizontally, the individual must have the ability to pro- duce a third dimension of movement to depress keys with a head pointer: forward and backward. There are also light pointers that can be worn on the head or held in the hand to control devices. One advantage of head-controlled light pointers is that it is not necessary for the user to move the head forward or backward. Light pointers are described in greater detail in the section on pointing interfaces.

Mouthsticks are often used by individuals who are quad- riplegic as a result of a spinal cord injury. A mouthstick con- sists of a pointer attached to a mouthpiece. The user grips the mouthpiece between the teeth and moves the head to manipulate control interfaces or other objects. The shaft of the mouthstick can be made from a wooden dowel, a piece of plastic, or aluminum. In some cases, interchangeable tips for different functions (e.g., painting, writing, typing) can be inserted into the distal end of the shaft. The mouthpiece can be a standard U shape that is gripped between the teeth or a custom-made insert. Puckett et al (1988) identify a number of criteria for design of a mouthstick. Mouthsticks are also available from several suppliers. Use of a mouthstick requires good oral-motor control; later in this chapter training to develop these skills is discussed.

The consumer’s range and resolution with the control enhancer can be determined by using the same methods discussed in Chapter 4. In some cases, particularly if there is a need to extend the consumer’s range (e.g., when the head is the likely control site), it is apparent at the begin- ning of the evaluation that the consumer will benefit from using a control enhancer. When the user has adequate range but resolution is in question, it may not be obvious during the physical-sensory evaluation whether a control enhancer will be beneficial. In these cases it is recommended that comparative testing of candidate interfaces with and with- out the use of control enhancers be completed. This evalu- ation provides the ATP with objective data regarding the effectiveness of the control enhancer. Certain control inter- faces, however, cannot be activated with a control enhancer. These include displays specially designed to be used with light pointers, eye-controlled systems, or capacitive switches requiring skin contact for activation (Lee and Thomas, 1990).

CONTROL INTERFACES FOR DIRECT SELECTION

Because the most rapid selection method is direct selection, it is generally preferable to indirect selection. Control inter- faces for direct selection include various types of keyboards, pointing interfaces, speech recognition, eye-gaze, gesture

recognition and cortical signals. Several of these approaches use on-screen keyboards. The critical questions presented in Box 7-2 can assist the ATP in determining the consumer’s ability to use any keyboard. As each question is considered, a “yes” answer means that the evaluation is proceeding on the correct pathway and the ATP should continue with the next question. Affirmative responses to all seven questions indicate that the control interface by itself is likely to meet the consumer’s needs.

The answer to the first question is determined by asking the consumer to reach the keys at each corner of the key- board. To obtain an answer to the second question, the con- sumer should be asked to press several keys located in different areas of the keyboard. The consumer’s rate of input can be timed for entering characters. Accuracy can be meas- ured by monitoring errors made during these tasks. In some situations, speed is of primary importance (e.g., in a work setting). In general, speed and accuracy are in opposition; that is, as speed increases, accuracy decreases. In some cases, to be accurate the consumer may make selections so slowly and deliberately that the use of the control interface under investigation becomes impractical. For example, if it takes several seconds to select a key, this rate may be equivalent to the use of scanning to make a selection. Because scanning takes much less physical effort, it should then be considered as an alternative to direct selection. Computer-assisted methods to measure speed and accuracy data are described in Chapter 4. The criterion for accuracy is somewhat subjec- tive and is subject to clinical judgment. We recommend that at least three out of four selections (75%) be correct.

If the answer to any of the questions in Box 7-2 is deter- mined to be “no,” then the use of a control enhancer, modi- fications, or a less-limiting keyboard should be considered. For example, if a standard keyboard cannot be used because of a targeting problem, the following may be considered: (1) an enlarged keyboard with larger targets (less limiting), (2) a keyguard (modification), or (3) a typing aid (a control enhancer). Modifications apply to all types of keyboards and are addressed after the discussion of the different types of keyboards.

Keyboards

For written communication, a keyboard is typically consid- ered the most efficient means of inputting information. The standard keyboard is the first choice for computer access. However, many individuals with disabilities are unable to use a standard keyboard. Fortunately, there are a number of alternatives. Table 7-2 provides examples of some commer- cially available alternatives to the standard keyboard.

Standard Keyboards. Some individuals may have dif- ficulty writing because of fatigue or minimally impaired motor control. A standard keyboard on a computer may be

236 C H A P T E R 7 Human/Assistive Technology Interface

all that is needed to allow them to complete writing tasks effectively. Because it is readily available, the standard key- board is the most desirable interface for direct selection for text entry. The standard keyboard typically has a full alphanumerical array consisting of letters, numbers, punctu- ation symbols, and special characters such as \/@#$%. Computer keyboards also have special keys. Some of these always have the same effect, such as END, which moves the cursor to the end of a line, or DEL, which erases an entry. Function keys can be assigned to special purposes dictated by a software application. In addition, most computer key- boards contain keys such as SHIFT, CONTROL, and ALT that are referred to as modifier keys because pressing one of these keys while another key is pressed changes the meaning of the second key. Key size, spacing, and amount of distance the keys travel vary depending on the type and manufacturer of the keyboard. To keep the overall size down, laptop com- puters in particular have smaller keyboards. For this reason, it is wise to have the consumer try the particular type of key- board he or she will be using.

Built-in Software Adaptations to the Standard Keyboard. Persons with disabilities often have difficulty in pressing more than one key at a time because they are single-finger typists. They may also have accidental key activation as a result of poor fine motor control. Software adaptations for these and other problems are shown in Table 7-1. These software adaptations are built into Windows and Apple Macintosh operating systems. Collectively these are called accessibility options in Windows XP (Microsoft accessibility Web site: http:// www.microsoft.com/enable/products/windowsxp/default.aspx), Easy Access in Windows Vista (Microsoft accessibility Web site), and Universal Access for the Macintosh. They are accessed and adjusted for an individual user through the control panel. Universal access for the Macintosh includes Easy Access and CloseView. Easy Access features are those shown in Table 7-1. When StickyKeys is used, the modifier keys are converted to sequential rather than simultaneous use, which allows other effectors (e.g., the head and foot) to also be used to access standard keyboards. In many cases there is also a need for StickyKeys (Windows and Macintosh) and FilterKeys (Windows) or SlowKeys (Macintosh) adaptations. FilterKeys includes the functions of BounceKeys, SlowKeys, and RepeatKeys. In Windows a number of options can be chosen to make the keyboard and mouse faster and easier to use. Options that can be adjusted are described on the Microsoft Web site (www. microsoft.com/enable/products/windowsxp/default.aspx).

There is an on-screen keyboard utility in Windows that operates in a manner similar to those described later in this chapter, but it has only basic functionality. Two modes of entry are available when an on-screen key is highlighted by mouse cursor movement: clicking and dwelling. In the latter

the user keeps the mouse pointer on an on-screen key for an adjustable, preset time and the key is entered. The on-screen feature also allows entry by scanning with a hot key or switch-input device. Several keyboard configurations are included, and an auditory click may be activated to indicate entry of a character. Windows combines the on-screen key- board, Narrator, and the magnifier program and a utility manager in its accessibility menu, which is accessed through the start menu. The Accessibility Wizard guides the user through the accessibility options to configure the system specifically for his or her use. Windows Vista also includes a built-in automatic speech recognition system.

Ergonomic Keyboards. The term repetitive strain injury (RSI) encompasses several musculoskeletal disorders that develop as a result of sustained, repetitive movements (Bear-Lehman, 1995). Carpal tunnel syndrome is the most common RSI. It is thought that the use of a standard key- board with horizontal rows on a flat platform may con- tribute to RSI in some individuals. Standard keyboards place the hands in an unnatural position with the forearms pronated and the wrists extended and ulnarly deviated. This position causes strain on the tendons and nerves. Numerous alternatives to the standard keyboard have been developed in attempts to reduce this strain on the wrist and hands. These alternatives range from minor rearranging of the keys to major redesign of the keyboard shape and configuration. Here ergonomic keyboards, those keyboards that have been designed with the intent of minimizing the risk of RSI, are discussed. These ergonomic keyboards all use the QWERTY keyboard layout (see Figure 7-12, A) with the keys repositioned in some way. Later in this section modifi- cations to the standard QWERTY keyboard layout are discussed.

Ergonomic keyboards attempt to reduce the strain placed on the hands and wrists during the repetitive motion of keying by putting the forearms, wrists, and hands in a neu- tral position, which is more natural and more comfortable for the typist. There are three basic ways in which the stan- dard keyboard has been redesigned. The first and most common type of ergonomic keyboard is the fixed-split key- board. In this type of keyboard the layout of the keys is split into two different sections. The center of the keyboard may also be slightly raised with a small slope toward each side. The difference between these keyboards and standard keyboards is that the keys are spaced farther apart and the keyboard is curved so that the hands are placed in a more neutral position. Many of these keyboards have a built-in wrist rest to support the wrists during typing. The Tru- Form Keyboard shown in Figure 7-13, A, is one example of this type of keyboard.

The second basic type of ergonomic keyboard is the adjustable-split keyboard. This type also splits the keyboard layout into two parts. A mechanism on the keyboard allows

P A R T III The Activities: General Purpose Assistive Technologies 237

one or both sides of the keyboard to be adjusted horizontally and vertically to the position where it is most comfortable. Each section of the split keyboard typically adjusts from 0 to 30 degrees. A user who is a 10-finger typist and does not need to look at the keyboard may be able to take advantage of this range of adjustment. However, for those individuals who need to have the keyboard in the visual field, adjusting the angle too far may make it difficult to see the keys. An example of this type of keyboard is the Maxim Adjustable Keyboard shown in Figure 7-13, B.

The third type of ergonomic keyboard uses a concave keywell design. The keyboard layout again is split into two

sections, but in this design the keys are arranged in a well such as that shown on the Contoured Keyboard in Figure 7-13, C. The principle behind this design is that finger excursion is reduced by having the keys arranged at the same distance from each of the finger joints (Anson, 1997). Other prod- ucts for all three types of ergonomic keyboards can be found at www.tifaq.org/keyboards.html.

Manufacturers of ergonomic keyboards claim that their keyboards reduce the strain placed on the wrist and hands. However, the use of ergonomic keyboards in reducing symp- toms of RSI has not been demonstrated in controlled studies. For this reason, it is advised that ergonomic keyboards not be

238 C H A P T E R 7 Human/Assistive Technology Interface

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Figure 7-12 A, Standard QWERTY layout. Dvorak keyboard layouts: B, two-hand layout; C, one-hand layout, right hand; D, Chubon keyboard layout for a typist who uses a single digit or a typing stick.

recommended for the purpose of preventing RSI (Anson, 1997; Tessler, 1993). Situations in which an ergonomic keyboard may be recommended for a consumer include (1) meeting the needs of consumer with physical limitations (e.g., limits in range of motion) and (2) when the consumer finds the ergonomic keyboard more comfortable to use than a standard keyboard. The most critical factor to consider when selecting a keyboard is the user’s level of comfort with the different keyboards (Anson, 1997).

Expanded Keyboards. Individuals who do not have sufficient resolution to target the keys on a standard key- board but still have adequate resolution to select directly may be able to use an expanded keyboard. Expanded key- boards are generally membrane-type keyboards that have enlarged target areas from which the individual can select directly (Figure 7-14, A). The minimum size of the target areas on an expanded keyboard is 1 inch square. If the per- son still has difficulty targeting this size of key, the expanded

keyboard can be customized by grouping keys together to form larger keys. In this way the keyboard can be redesigned to match the skills of the user.

Expanded keyboards vary in overall size and can be cho- sen depending on the size of the selection set needed by the individual and the key size the individual is able to target accurately. IntelliKeys has a large surface area that can be configured for a variety of key sizes and shapes. It comes with several standard keyboard overlays, such as the one shown in Figure 7-14, B. This overlay is an example of a layout that has been configured with different sizes and dif- ferent shapes of keys on the same keyboard. The IntelliKeys can also be customized to match specific applications by using the companion Overlay Maker software. The keys can be labeled with letters, words, symbols, or pictures. Because they can be customized, expanded keyboards are also useful with individuals who have a cognitive or visual impairment. Examples of expanded keyboards are shown in Table 7-2.

Contracted Keyboards. Some individuals may have sufficient resolution but lack the range of movement to reach all the keys on a standard keyboard. In this situation a contracted, or mini, keyboard may be the solution. These keyboards use either raised keys or a membrane surface. For computer use, contracted keyboards must meet the require- ment that all keys of the standard keyboard be represented, which is accomplished by using additional modifier keys. Figure 7-15 shows a consumer being evaluated using a mouthstick with the USB Mini keyboard. This keyboard is approximately 7.25 × 4.2 inches in overall size, with the size of each key approximately one half inch on a side. Several of the keys have multiple functions, depending on which mod- ifier key is pressed first. The functions corresponding to var- ious modifiers can be colored to match the modifier key. The selection set (the alphabet) in Figure 7-15 is not placed in the QWERTY format typical of standard keyboards. The letter placement is based on a “frequency of use” system in which the letters most commonly used in the English lan- guage are placed toward the center, with the less commonly used letters placed in the outer edges of the keyboard. This arrangement particularly makes sense to use on a contracted keyboard where the individual’s range of motion is restricted. Because of the small key size and closeness of the keys, the user of a contracted keyboard must have good fine motor control. Persons using contracted keyboards type with a single digit, a handheld typing stick, or a mouthstick.

Special-Purpose Keyboards. Keyboards are also used on special-purpose devices, such as augmentative communi- cation and environmental control devices. In these cases the available keys may be much more limited in number or they may be very specific in function compared with the standard keyboard. For example, in portable augmentative

P A R T III The Activities: General Purpose Assistive Technologies 239

C

B

A

Figure 7-13 Ergonomic keyboards. A, The Tru-Form Keyboard. B, The Maxim Adjustable Keyboard. C, The Contoured Keyboard. (A, Courtesy Adesso Inc., www.adessoinc.com; B and C, courtesy Kinesis Corporation, www.kinesis-ergo.com.)

communication devices such as the SpringBoard, the key- boards have membrane keys and are restricted to a total of 32 keys (see Chapter 11). These keys are not assigned any specific character or function when manufactured but can be programmed to represent just about anything the user would like. Other devices come with certain keys that have been designated to be specific functions. For example, a key may be designated “SPEAK,” and pressing it will cause whatever was entered to be spoken. In all these cases, however, the key- board provides the same function: direct selection input from the user to the processor.

Dedicated communication devices can also be used as input devices for a general-purpose computer. The commu- nication device is connected to the computer through a serial or USB interface. This connection allows the commu- nication device to send characters to the computer as if they were typed from the computer keyboard. Because the user of the communication device is familiar with the keyboard on the communication device, it is easy for him or her to use it for computer entry and the user does not have to learn another keyboard arrangement. Another advantage is that any words or phrases that are stored in the communication

240 C H A P T E R 7 Human/Assistive Technology Interface

B

A

Figure 7-14 A, Consumer using an expanded keyboard with thumb. B, Expanded keyboard showing configuration with different sizes and shapes of keys on the same keyboard.

device can be sent to the computer as words or phrases as well. A standard has been developed to allow all keyboard characters to be sent to the computer, even if the communi- cation device does not have that character. For example, computer keys such as DEL may not be on the communica- tion device, but the user can send a sequence of characters that the computer interprets as the DEL key. Selection of a special-purpose keyboard for a consumer also requires care- ful consideration of the items presented in Box 7-2.

Automatic Speech Recognition as an Alternative Keyboard

Automatic speech recognition (ASR) technology can be applied to computer access by allowing the user to speak the names of keys or key words and have these spoken utterances interpreted by the computer as if they had been typed. This approach is appealing because human speech is so rapid and voice control is so natural. ASR systems that are extremely reli- able, flexible, and easy to use are available for use as full-function keyboard and mouse emulation. For example, if a word process- ing program is being run, then control functions such as delete, move, and print and the most common vocabulary the person normally uses, a greeting and ending for a business letter, and other similar vocabulary items can be used. If the user changes to a spreadsheet program, he or she can use vocabulary that contains items specific to that application. Microsoft Vista includes ASR as part of the built-in package of accessories.

Two basic types of ASR systems exist. With a speaker- dependent system, the user trains the system to recognize his or her voice by producing several samples of the same ele- ment. The method in which the training is handled varies among systems. The system analyzes these samples so that

P A R T III The Activities: General Purpose Assistive Technologies 241

Figure 7-15 Consumer using the WinMini Keyboard and a mouthstick being evaluated.

CASE STUDY

EVALUATION AND SELECTION OF SPEECH RECOGNITION

Marilyn Abraham is a 44-year-old woman who has been diagnosed as having reflex sympathetic dystrophy (RSD) of both wrists. Apparently caused by vasospasm and vasodilation, RSD is a reaction to pain after an injury (Kasch, Poole, and Hedl, 1998). It results in edema; shiny, blotchy skin; and pain. Ms. Abraham is a secretary in a large state office, which she shares with other coworkers. She uses the computer for much of the day. The RSD ensued in her right wrist as a result of the repetitive motion she uses in performing her job. After this injury she received retraining to transfer her hand dominance to her left hand, and the Dvorak one-handed keyboard layout was recommended (see Figure 7-12). Subsequently she broke her left wrist in a motor vehicle accident, which also resulted in RSD. She is able to type or use the mouse for only 10 minutes before her hands and forearms swell. Ms. Abraham has tried different positions and adaptations when typing. For example, she used a pointer held by a cuff in her palm to type so that her forearm remained in a neutral position. This method still resulted in swelling and pain. She also has neck pain when she uses the keyboard.

Ms. Abraham first tried using a trackball with her hand and the on-screen keyboard. After using the track- ball for a short time, Ms. Abraham found that it also caused pain. Ms. Abraham next tried using her right foot with an expanded keyboard and then a trackball. There were concerns about the utility of both these approaches because of potential neck strain from look- ing down and that possibility that the repeated move- ment of her ankle to input characters using the trackball might lead to repetitive motion problems with her foot.

Next Ms. Abraham tried a head-controlled interface that was worn on a band and attached to her head. She used this interface with an on-screen keyboard and acceptance time to make a selection. She was able to control this interface without difficulty but thought that after a period of use her neck would become tired.

QUESTIONS

1. What other control interfaces could you try with Ms. Abraham?

2. If you evaluate automatic speech recognition for Ms. Abraham, what issues will you need to take into consideration?

it can recognize variations in the user’s speech and generate a computer input (e.g., enter a given letter, a string of letters, or a control key like “return”) corresponding to what was spoken. Even after the system has been trained with several speech samples, there likely will be times when the system does not recognize the user’s speech and does not produce a response. Recognition accuracy is steadily increasing as advances are made in the computer algorithms used for analysis. Rates can be greater than 90% for general input and nearly 100% for isolated word applications (e.g., command and control, database, spreadsheet). Speaker-dependent sys- tems can be further divided into continuous and discrete categories. Comerford, Makhoul, and Schwartz (1997) describe the development of ASR systems and describe the technical aspects of these systems.

Speaker-independent systems recognize speech patterns of different individuals without training (Gallant, 1989). These systems are developed by using samples of speech from hundreds of people and information provided by phonolo- gists on the various pronunciations of words (Baker, 1981). The tradeoff with this type of total recognition system is that the vocabulary set is small. In assistive technology applications, speaker-independent systems are primarily used for environmental and robotic control (Chapter 14) and power mobility (Chapter 12).

Discrete speech recognition systems require the user to pause between each word for recognition to occur, which is a very unnatural type of speech. There have been reports of voice problems associated with the use of discrete speech recognition systems (Kambeyanda, Singer, and Cronk, 1997). These are due to the abrupt starting and stopping of speech required for these systems, coupled with the mono- tone quality required for good recognition, both of which are unnatural speech patterns. Continuous ASR systems allow the user to speak in a more normal manner, without major pauses. The rates of input are within the range of normal rates of human speech (150 to 250 words per minute). Although the possibility of damage to the vocal folds is reduced with these systems, it is not totally eliminated. Because the discrete systems are more accurate for single-word recognition, they are sometimes used for commands and

control in applications such as spreadsheets and databases. Some manufacturers (e.g., Dragon Systems, Nuance, Inc., Burlington, Mass., http://www.nuance.com/) provide both continuous (e.g., Naturally Speaking) and discrete (e.g., Dragon Dictate) ASR, sometimes bundled into the same package. Currently used speech recognition systems are listed in Table 7-8. The majority of these use continuous recognition.

Speech recognition can be used for computer access, wheelchair control, and EADLs. The systems shown in Table 7-8 allow the consumer to use speech to enter text directly into a computer application program. Recognition of control words, such as “save file,” used in a word processor is also trained. System vocabulary is also growing rapidly. Early systems had recognition vocabularies (the list of words the system can recognize when spoken) in the 1000 to 5000 range. Current systems have vocabularies of 50,000 words or more. The faster speech rate, larger vocabularies, and contin- uous recognition all place significant demands on the speed and memory of the host computer. Continuous speech recognition systems require large amounts of memory and high-speed computers. As the cost of this added computer functionality continues to decline, these additional require- ments will be less important. However, ASR systems do require more computer resources than other alternative input methods (Anson, 1999).

There are other hardware issues that are important in ASR as well. Foremost of these is the microphone. Anson (1997) discusses considerations in the choice of a micro- phone for ASR. Although the microphones supplied with ASR systems are satisfactory for use by nondisabled users, they are not adequate when the user has limited breath sup- port, special positioning requirements, or low-volume speech. Most ASR systems use a standard headset micro- phone. Individuals who have disabilities may not be able to don and doff such microphones independently, and desk- mounted types are often used. Current ASR systems do not require separate hardware to be installed in the computer, and they use commonly available sound cards (Anson, 1999).

EADLs may also use speech recognition to access their functions (see Chapter 14). In such devices the individual can

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Speech Recognition Interfaces

Category Description Device Name/Manufacturer

Speaker-dependent systems Recognition depends on the system’s learning Naturally Speaking and Dragon Dictate (Dragon the user’s speech patterns and building Systems); Via Voice (IBM); Hear-Say a user vocabulary. (Voice Pilot Technologies)

Speaker-independent systems The operation is similar to continuous speech Used in special-purpose assistive devices for recognition systems, but there is no training environmental control or robotic control required. Generally limited to small, (see Chapter 14) and wheelchair control application-specific vocabularies. (see Chapter 12).

TABLE 7-8

instruct the system to turn lights off and on or perform other functions by voice. The user can train the system to execute these commands with just about any sound, letter, or word.

The questions listed in Box 7-3 can be used to determine the usefulness of speech recognition for a given consumer. The key for success in using speech-activated systems is that the user be able to produce a consistent vocalization or verbal- ization. Differences in speech production are found not only among individual speakers but also within the same speaker. Variability in the user’s speech can cause problems with recog- nition. For this reason, this type of control interface may not be effective for individuals who have dysarthria. Individuals who have had a spinal cord injury and have no functional use of the upper extremities yet have good speech control are potential candidates for a speech recognition system. It is important when considering a speech recognition system to determine whether the user’s voice pitch, articulation, and loudness change or fatigue over time. Other noises or voices in the area where the speech-activated system is being used can also confuse the system, resulting in either an incorrect selection or the system having difficulty registering any selec- tion, causing the user to repeat the vocalization several times.

Touch Screens and Touch Tablets

Touch screens are available on augmentative communication devices and laptop, palm, and notebook computers that the user activates by pointing directly to the selection set on the screen. Using a touch screen makes selection cognitively eas- ier for many users, particularly young children, because it is more direct and intuitive. These interfaces are activated by either breaking a very thin light beam or by a capacitive array that detects the electrical charge on the finger. The electrode array used to detect where the finger, or pointer, is touching is transparent, and the touch screen can be placed over the face of a monitor. In either detection method an array of horizontal and vertical sensors is arranged so that an object the size of a finger will be detected. The position in the array determines what the interpretation of the pointing action will be, just as the specific key on a keyboard determines what the

input will be. Separate touch screens can also be attached to the computer monitor or placed over a selection array on a tabletop or other flat surface. The selection set varies with the application program being used.

TongueTouch Keypad

The TongueTouch Keypad, shown in Figure 7-16, consists of nine separate small switches incorporated into a dental mouthpiece that fits in the roof of the mouth. It is a battery- operated, radio frequency–transmitting interface that acti- vates a processor that sends IR signals to the computer. Each of the nine switches corresponds to one choice on a menu presented on a computer screen. The first menu provides choices of environmental control (e.g., television, lights), computer access (keyboard emulation), and wheelchair control. Once one of these categories is chosen, nine more choices pertaining to that category are presented, such as volume and channel control for the television; letters, key- board array, and mouse movement directions for computer entry; or numerical choices for telephone dialing. This approach is useful for individuals who do not have motor control in their limbs but have good head, neck, and oral- motor control. In particular, the user must have good eleva- tion of the tip of the tongue to activate the individual keys efficiently (Lau and O’Leary, 1993).

Access for Users With Cognitive Limitations

Concept keyboards replace the letters and numbers of the keyboard with pictures, symbols, or words that represent the concepts being used or taught. When the user presses on the picture, the correct character is sent to the computer to create the desired effect. As an example, a child who is having difficulty with basic arithmetic and monetary con- cepts may be more successful using a concept keyboard in which each key displayed is a coin of a particular denomina- tion, rather than the value (number) or name of the coin (letters). The child can push on the coin and have that num- ber of cents entered into the program. A simple program that asks the child to make change could be used to encour- age the child to develop subtraction skills while also learn- ing the value of specific coins. This approach is more motivating for some children and it is easier to press on a key labeled with a quarter than to enter “2” and “5.”

Very simple programs may require only two keys. For example, the SPACE key can move a cursor to different matching choices and the RETURN key can select the desired one. This concept can be used to match shapes or numbers or to control any two-choice task. It functions as a keyboard, although only two keys are used.

Another approach to concept keyboards is the use of spe- cially designed software together with special-input keyboards. These systems do not require the use of a special input interface

P A R T III The Activities: General Purpose Assistive Technologies 243

BOX 7-3 Critical Questions for Evaluating Use of Speech Recognition Interface

1. Can the consumer consistently utter all the sounds necessary to access the speech recognition system?

2. Is the recognition vocabulary adequate? 3. Is the consumer’s voice articulation, pitch, and loudness

consistent enough for accurate selection? 4. Is there likely to be background noise in the consumer’s

context that will interfere with the speech recognition system?

5. Would an alternative template or vocabulary be beneficial?

because they plug directly into a serial, parallel, or USB port. The software also comes with overlays for the keyboard. For example, a program to teach language concepts can be implemented by placing pictures of the concepts on specific keys and having the child generate words by pressing the correct key, causing the concept to be spoken and the picture to be repeated on the screen. When the child plays with the objects described, he or she learns to label his or her actions as well as the objects. Concept keyboards provide a direct relationship between the task and the child’s action. For example, by using a picture of the body as the “keyboard” and each body part as a “key,” a child can touch the body part when the program instructs him or her to do so. When the child does, the program can repeat the body part name and cause it to be moved on the screen. The Intellikeys (IntelliTools, Petaluma, Calif., www.intellitools.com) key- board is often used as a concept keyboard.

An even more direct concept keyboard is the Touch Window. With this device the user merely touches the screen at the proper place and the touch screen enters the informa- tion as though it has been typed. Monitors with built-in touch screens are also available for Macintosh and Windows computers. Moving the finger on the screen can also be used to draw. This device can be placed horizontally on a table or

lap tray and used as a concept keyboard with an appropriate overlay. On-screen keyboard arrays can also function as con- cept keyboards with the choice of on-screen elements.

There are also commercial emulation programs that reduce the complexity of the Windows environment for users who have cognitive disabilities. The Voyager suite of programs from Saltillo (Saltillo, Millersbery, Ohio, http://saltillo.buyol.com/Item/Voyager_Desktop_Suite.htm) allows individuals with cognitive disabilities to launch pro- grams, communicate by e-mail, and browse the Web. The entire suite operates with pictures rather than words to present the user with choices removing the necessity for the user to be able to read or write. Receiving e-mail is accom- plished by using text to speech to provide an auditory output. The user sends e-mail by selecting a set of pictures that enable the send function, select the recipient by picture or name, and then prompt the user to record a message and send it. Assistive technologies for persons with cognitive limitations are discussed in more detail in Chapter 10.

Eye-Controlled Systems

Often consumers use the direction of eye gaze as the only means of indicating. Manual eye-controlled communication

244 C H A P T E R 7 Human/Assistive Technology Interface

Dental acrylic molded to fit

against the hard palate

TongueTouch Keypad

TongueTouchTM

Keypad

Personal Computer

ComputerLink

RF Receiver, Display and IR

Transmitter

Zofcom Controller

Teeth clasps

Figure 7-16 Components of the TongueTouch Keypad. (From Lau C, O’Leary S: Comparison of computer interface devices for persons with severe disabilities, Am J Occup Ther 47:1022-1029, 1993.)

systems have been in use for a long time. In manual systems the user communicates “yes” or “no” though eye blinks or uses the eyes to point to letters on an alphabet board to spell utterances. This manual form of using eye movement as a means of input can be automated by electronically detecting the user’s eye movements as a control interface for direct selection.

There are currently two basic types of eye-controlled systems. One type uses an IR video camera mounted adja- cent to a computer display. An IR beam from the camera is shined onto the person’s eye and then reflected by the retina. The camera picks up this reflection of the individual’s eye as he or she looks at the on-screen keyboard appearing on the computer monitor. Special processing software in the com- puter analyzes the images coming into the camera from the eyes and determines where and for how long the person is looking on the screen. The user makes a selection by look- ing at it for a specified period, which can be adjusted accord- ing to the user’s needs. The EyeGaze System, Quick Glance, ERICA (Eye Response Technologies, Charlottesville, Va., www.eyeresponse.com), and Tobii (TobiiTechnology, San Francisco, Calif., www.tobii.com) are examples of two- eye–controlled systems of this type. The design principles and approach to the ERICA system are described by Lankford (2000). The other type of eye-controlled system uses a head-mounted viewer that tracks the movements of one eye. This viewer is attached to one side of the frame of a standard pair of glasses so that it is in front of one eye. The movements from the eye are viewed and converted into key- board input by a separate control unit. One example of this type of system is VisionKey. Both types of eye-controlled systems provide the user with computer access for written or verbal communication, Internet access, environmental con- trol, and telephone operation. To operate either type of eye-controlled system, the user must have good vision and control of at least one eye, good head control, including the ability to keep the head fairly stationary, and the cognitive ability to follow instructions.

An eye-controlled system is beneficial for individuals who have little or no movement in their limbs and may also have limited speech, for example, someone who has had a brainstem stroke, has amyotrophic lateral sclerosis, or has high-level quadriplegia. Some disadvantages of eye-controlled systems are that sunlight, bright incandescent lighting, and contact lenses may interfere with system tracking, and the cost of such systems is still rather high in comparison with other input methods. For some individuals, however, it may be the only reliable means of control.

A disadvantage of eye-controlled systems is holding the point of gaze (POG) on a target long enough for selection by a dwell time or separate switch selection. An alternative is to use an EMG control to incrementally move the cursor in small steps by muscle activations. Because the cursor only moves if a muscle is activated, holding on a target is accomplished by

relaxing the muscle, and target acquisition is easier than holding the POG. However, moving large distances on the screen in small steps can be fatiguing. To take advantage of the benefits of POG for moving large distances and the EMG for narrowing down to a precise target and holding, a hybrid POG/EMG system has been developed (Barreto, Al-Masri, and Cremades, 2003). The system calculates the distance from the current cursor location to the POG of an eye tracking system. If this distance is small, then the EMG incremental stepping cursor movement is used. If the dis- tance is large, the POG is used to move to the vicinity of the target. Trials with subjects who are not disabled showed that the hybrid POG/EMG system had faster acquisition times for targets ranging from 8.5 to 22 mm. The variance was higher for the hybrid system, indicating that additional prac- tice and training are required to maximize its effectiveness.

Tracking of Body Features

Another approach to cursor control is the use of a camera to track body features (Betke, Gips, and Fleming, 2002). This system uses a digital camera and image recognition software to track a particular feature. The most easily tracked feature is the tip of the nose, but the eye (gross eye position, not POG), lip, chin, and thumb have also been used. The move- ment of the feature being tracked is converted into a signal that controls an on-screen mouse cursor. Betke, Gips, and Fleming (2002) describe the technical features of the system software in detail. Trials with nondisabled subjects in an on- screen game in which targets were “captured” by pointing the cursor at them showed that the camera mouse was accu- rate but slower than a typical hand-controlled mouse. With an on-screen keyboard used for a typing task, the camera mouse was half as fast as a regular mouse, but the accuracy obtained was equivalent on each system. Eleven persons with disabilities ranging in age from 2 to 58 years used the camera mouse. Eight of the 11 were able to control it reliably and continued to use it. With the increasing avail- ability of built-in cameras in computers, the camera mouse requires only a software program to capture the body feature image and interpret its movement as mouse commands, which may make this approach more common.

Brain-Computer Interface

A significant number of people cannot effectively use any of the interfaces described in this chapter. For these individu- als, the brain-computer interface (BCI) may offer promise. Although this approach is still primarily in the research stage, there are promising results to date. It is likely that we will see a much greater understanding of the biological/ physical interface for the control of computers in the future (Applewhite, 2004). Figure 7-17 is an overview of a typical BCI system (Schalk et al, 2004). Features or signals that

P A R T III The Activities: General Purpose Assistive Technologies 245

have been used include slow cortical potentials, P300 evoked potential, sensorimotor rhythms recorded from the cortex, and neuronal action potentials recorded within the cortex. The success of BCI systems depends on the type of brain signal, the methods of signal processing to extract relevant

features, the algorithms that translate the features into control signals (most often a mouse-like cursor movement on the screen), user feedback, and user characteristics. BCI systems may be grouped into a set of functional components (Mason and Birch, 2003). The BCI input device provides amplifica- tion, feature extraction, feature translation, and user feedback. The control interface converts this signal to those required to control the output device (e.g., power wheelchair, EADL, computer). The device controller provides the actual control signal to the target device (e.g., signals to the motors of a power wheelchair, mouse cursor movement signals to a computer). A typical task for a user is to visualize different movements or sensations or images. An example of differing signals measured on the surface of the cortex for different imagined motor acts is shown in Figure 7-18 (Leuthardt et al, 2004). The unique signal patterns shown in Figure 7-16 can be used to generate control signals. Schalk et al (2004) give technical details of the major approaches to BCI system design. Electrodes located on the surface of the cortex have stronger and more varied signals and less interfering muscle artifact and are more stable than those attached to the scalp (Leuthardt et al, 2004). Some sensorimotor patterns that can be measured from the surface of the cortex under the skull are too weak to be measured outside the skull. The invasive- ness of the electrocorticographic signals is the major draw- back. In all cases, signals are mathematically analyzed to extract features useful for control (Fabiani et al, 2004).

246 C H A P T E R 7 Human/Assistive Technology Interface

SIGNAL ACQUISITION

Feature Extraction

Translation Algorithm

DEVICE COMMANDS

DIGITIZED SIGNAL

SIGNAL PROCESSING

BCI SYSTEM

Figure 7-17 An overview of a typical brain control interface system. (From Schalk G et al: BCI2000: a general-purpose brain-computer interface (BCI) system, IEEE Trans Biomed Eng 51:1034-1043, 2004).

PATIENT D: IMAGINE SAYING "MOVE"

PATIENT D: IMAGINE PROTRUDING TONGUE

PATIENT B: IMAGINE MOVING RIGHT HAND

PATIENT C: IMAGINE SAYING "MOVE"

FREQUENCY (Hz)

FREQUENCY (Hz)

FREQUENCY (Hz)

FREQUENCY (Hz) 0 30 60 90

0 30 60 90

0 30 60 90

0 30 60 90

0.00 0.15 0.30 0.45 0.60

r2

0.00

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0.45

0.60

r2

0.00

0.15

0.30

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r2

0.00

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Figure 7-18 An example of differing signals measured on the surface of the cortex for different imagined motor acts. (From Leuthardt EC et al: A brain-computer interface using electrocorticagraphic signals in humans, J Neural Eng 1: 63-71, 2004.)

Standard and Alternative Electronic Pointing Interfaces

The other commonly used control interface for direct selec- tion in general-purpose computers is a mouse. There are also alternative pointing interfaces that can replace the mouse, such as a trackball, a head sensor, a continuous joystick, and the use of the arrow keys on the keypad (called MouseKeys). Box 7-4 identifies the critical questions to consider when assessing an individual for using any type of pointing interface.

It is necessary to determine whether the consumer can use the pointing interface to reach the items in the selection set (targets) and stay fixed on the target while executing the action needed to make a selection. These all imply that the selection targeted is accurate. The person may be able to get to a target area on the screen, but the size of the target may affect his or her ability to maintain that position while selecting it. Any location on the screen can be a target, and these can be of different sizes. Depending on the software program, the size of the target may be fixed or it may be pos- sible to modify the size to meet the user’s needs. The user can use one of two techniques to make a selection. With an acceptance time selection technique, the user pauses at the selec- tion for a predetermined period (which is adjustable) and that pause signals the selection. With the manual selection technique, the user activates another switch to let the device know that the selection has been made. The second approach provides more control for the user, but it also requires additional user motor control.

Pointing interfaces vary in terms of the tactile and pro- prioceptive feedback that they provide, which may affect the user’s performance. Using a pointing interface also requires a significant amount of coordination between the body site executing the movement of the cursor and the eyes follow- ing the cursor on the screen and locating the targets. The ATP should determine whether the layout of the items in the selection set is beneficial or detrimental to the user’s per- formance. The selection set and its layout will vary depend- ing on the pointing interface and the software being used.

It is important to know whether the layout of the selection set can be modified for a particular pointing interface and what type of modifications will benefit the user.

Mouse. The standard computer mouse is a solid box that rides on top of a ball. As the mouse is gripped by the user and moved across a flat surface, the ball rotates, causing the cursor on the screen to move. As the mouse moves, the computer

P A R T III The Activities: General Purpose Assistive Technologies 247

BOX 7-4 Critical Questions for Evaluating Use of Electronic Pointing Interfaces

1. Can the consumer use the pointing interface to reach all the targets on the screen?

2. Is the size and spacing of the screen targets appropriate? 3. Is the consumer able to complete the action needed to

make a selection and perform other mouse functions required by the application software (click, drag, and double click)?

4. Is the sensory feedback provided by the control interface and the user display adequate?

5. Does the consumer use the keyboard layout effectively?

CASE STUDY

EVALUATION AND SELECTION OF A POINTING INTERFACE

David is a 21-year-old man who has muscular dystrophy. He would like to be able to access the family computer for educational and recreational purposes. David would like to play computer-based games and use drawing programs that typically require a mouse. He lacks move- ment in his four extremities, with the exception of wrist and finger movement. He is able to reach with each hand from within 3 inches of his body to 8 inches out from his body. With his right hand he can reach approx- imately 5.5 inches to the right of midline and with his left hand he can reach 3 inches to the left of midline. He cannot cross midline with either hand.

David tried a contracted keyboard, and he was able to point to keys in a restricted range near the middle of the keyboard. He was unable to access other areas of the keyboard without assistance for repositioning of his arms. He was able to move a continuous joystick in all four directions and use it with the on-screen keyboard software, but this was difficult for him. A trackball was also used with the on-screen keyboard software to determine whether David could use it. He could easily use the trackball as a pointing device to point to the keys shown on the screen. Using a drawing program and the trackball, he was able to direct the cursor to var- ious parts of the screen with enough precision to draw lines and shapes. However, he was unable to hold the trackball in place with the cursor on the desired selec- tion and simultaneously press the button on the track- ball with the same hand to make his selection. The acceptance time selection technique was shown to him, and he was able to easily use this technique.

QUESTIONS

1. From the data given, should the ATP recommend a contracted keyboard for David?

2. From the information given, what would be the opti- mal control interface for David? What other informa- tion is needed regarding David’s needs and skills that might influence the recommendation?

3. What other software will David need to operate the recommended control interface?

screen shows a pointer that follows the mouse movement. The GUI is used as the selection set. In this type of selec- tion set, the screen contains a list of options, either written words or icons. If the mouse is moved to the option and a button is pressed (usually called clicking), then that item is chosen. Two rapid clicks are used to run, or execute, the pro- gram related to the icon. If the mouse button is held down while the mouse is pointing to a menu item and then the mouse is moved down the list (called dragging the mouse), a new list of choices appears. The GUI reduces the number of keystrokes and provides a prompting display for the user.

The mouse is ideally suited for functions such as draw- ing, moving around in a document, or moving a block of text. The mouse can be a useful tool for individuals with dis- abilities who cannot otherwise draw with a pen or pencil. However, mouse use requires a high degree of eye-hand coordination and motor coordination and a certain amount of range of motion. The standard computer mouse is avail- able in many different shapes and sizes. If a consumer is hav- ing difficulty using the mouse that came with the computer, the solution may be as simple as finding a mouse that fits his or her hand better. The standard mouse requires a great deal of motor control, however, and many individuals with

disabilities find that the use of a standard computer mouse is difficult or impossible. Another option is to try a different control site for mouse use. If the consumer has better con- trol of his feet than his hands, his foot can be used with a foot-controlled mouse such as the No Hands Mouse. There are also alternatives to mouse use that are easier for many persons with disabilities. Any control interface that can imi- tate the two-dimensional movement (up/down, left/right) of the mouse can be made to look to the computer like a mouse. Table 7-9 lists the major alternatives to mouse input and sample technologies. Examples of several of these approaches are shown in Figure 7-19.

Keypad Mouse. For those individuals who are able to use a standard keyboard but have difficulty using a standard mouse, the first alternative to evaluate is the keypad mouse. A numerical keypad is embedded in most standard com- puter keyboards. MouseKeys, included in the accessibility options for Windows and in the Macintosh operating sys- tems, allows use of the keypad to simulate mouse movement. When the NUM LOCK key is engaged, each key on the numerical keypad functions as the number to which it is assigned (1 to 9). When the NUM LOCK key is disengaged

248 C H A P T E R 7 Human/Assistive Technology Interface

Alternative Electronic Pointing Interfaces

Category Description Device Name/Manufacturer

Keypad mouse Mouse movement is replaced by keys that move the mouse R.A.T. (Adaptivation, Inc.) cursor in horizontal, vertical, and diagonal directions. One or more keys perform the functions of the mouse button (click, double click, drag).

Trackball Looks like an inverted mouse; a ball is mounted on a stationary Big Track, n-Abler (Inclusive Technology); base. Included on the base are one or more buttons that EasiTrax (Inclusive Technology); provide the functions of the standard mouse buttons. The base Trackman Marble Plus (Logitech); and hand remain stationary and the fingers move the ball. EasyBall (Microsoft); Roller Trackball Requires minimal range of motion and less eye-hand coordination. (Traxsys Computer Products)

Continuous input Joysticks (continuous input and switched) are used as direct Jouse (Compusult Limited); Roller Joystick II joysticks selection interfaces for powered mobility. For computer use, (Traxsys Computer Products); EasiTrax

movements are similar to wheelchair control; easy to relate (Inclusive Technology); all manufacturers cursor movement (direction, speed, and distance) to of power wheelchairs have their own joystick movement. joysticks, which are supplied with wheelchair

Head-controlled An interface controlled through head movement; the user wears Head Master Plus (Prentke Romich Co.); mouse a sensor on the head, which is detected by a unit on the computer. Head Mouse (Origin Instruments Co.);

Movement of the head is translated into cursor movement on Tracker (Madentec Ltd. Communications); the screen. smartNAV-3 (Inclusive Technology)

Light pointers and These devices either emit a light beam that can be used to point Light-operated Ability Switch (Ability light sensors to objects or as a control interface, or they receive light and Research, Inc.); Lomac (Inclusive

provide an output when the light is reflected from an object Technolgy); Viewpoint Optical Indicator or the light beam is interrupted. (Prentke Romich); Infrared/sound/touch

switch (Words Inc.)

Data from Ability Research, Inc., Minnetoka, Minn. (www.skypoint.com/P5ability/contacts/html); Adaptivation, Sioux Falls, S.D. (www.adaptivation.com); Compusult Limited, Mount Pearl, Newfoundland (http://www.jouse.com/html/about.html); Logitech, Fremont, Calif. (www.logitech.com); Inclusive Technology (http://www.inclusive.co.uk/catalogue/index.html); Madentec Limited, Edmonton, Alberta (www.madentec.com); Microsoft, Redmond, Wash. (www.microsoft.com); Origin Instruments, Grand Prairie, Tex. (www.orin.com); Traxsys Computer Products (http://assistive.traxsys.com/staticProductListing.asp); Prentke Romich Co., Wooster, Ohio (www.prenrom.com); Words+ Inc. (www.words-plus.com).

TABLE 7-9

and MouseKeys is running, these keys can perform the same functions as a mouse. The “5” key serves as a mouse click, and the surrounding number keys move the mouse in verti- cal, horizontal, or diagonal directions. This software inter- prets the keys as mouse input when MouseKeys is active and interprets them as arrow keys when it is not active. MouseKeys allows adjustment of the mouse speed (distance the cursor moves with each arrow key press) and acceleration (the rate at which the cursor moves).

There are also keypad mice that are external to the stan- dard keyboard, such as the Micro Pad. The advantage of external keypads is that they can be placed in any position in the workspace. The disadvantage is that they take up more space on the work surface. External keypad mice are also available with enlarged keys, such as the Expanded Keypad and the Big Blue Mouse, both of which have 1.5-inch square membrane keys. When a trackball, joystick, or other hardware alternative is substituted for the mouse, it is nec- essary to accommodate the mouse buttons including click- ing (rapid press and release), double clicking, and dragging (holding the button while moving the mouse). Software adaptations replace these mouse button functions by select- ing which mouse button function is required and then implementing that function when the user pauses on the selection.

Trackball. Use of a trackball is one approach that was developed for the able-bodied population but has often been found to be helpful for persons who cannot use the mouse. This device looks like an inverted mouse; a ball is mounted on a stationary base. Included on the base are one or more buttons that provide the functions of the standard mouse but- tons. The ball is rotated by moving the hand or finger across it, causing the cursor to move on the screen. Because the base and hand remain stationary and the fingers move the ball, this approach requires less range of motion than the standard mouse and is easier for some disabled users. It is also possible

to use the trackball easily with other body sites such as a chin or foot. On most trackballs the user can latch the mouse button, which allows single-finger or mouthstick users to perform “click and drag” functions without having to hold down a button while simultaneously moving the mouse. Trackballs are available in a variety of sizes, shapes, and configurations. There are trackballs (such as the Trackman Marble Plus) in which the ball is positioned on the side where it can be controlled by the thumb. There are also very small trackballs, such as the Thumbelina Mini Trackball, that fit in the palm of the hand. Having the con- sumer try the different types of trackballs is important, even if this means taking a trip to a local computer store that has different models available for demonstration.

Continuous Input Joysticks. A joystick provides four directions of control and is thus ideally suited for use as another alternative to the mouse. There are two types of joysticks: proportional (continuous) and switched (discrete). A proportional joystick has continuous signals, so any move- ment of the control handle results in an immediate response by the command domain in that direction. By using a pro- portional joystick, the individual can control not only direc- tion of movement but also the rate of that movement. Proportional joysticks are most commonly used with power wheelchairs. The farther the wheelchair joystick moves away from the starting point, the faster the wheelchair goes. The proportional joystick is also more likely to be used as a mouse substitute because the direction and rate of cursor movement can be controlled by the user. The Jouse is a joy- stick-operated mouse that is controlled with the chin or mouth. Mouse button activations can be made by using a sip-and-puff switch that is built into the joystick. Just like the proportional joystick used for wheelchair control, the joystick used for a mouse substitute will cause the mouse pointer to move faster the farther away it gets from the cen- ter position. A major difference between mouse and trackball

P A R T III The Activities: General Purpose Assistive Technologies 249

BA C

Figure 7-19 Pointing interfaces. A, Standard computer mouse. B, Trackball. C, Proportional joystick.

use and the use of a joystick is that the joystick is always ref- erenced to a center point, whereas the mouse cursor move- ment is relative to the current position. This difference in reference point can cause difficulties for the consumer when first using the joystick. The user must spend some time learn- ing how to use this control interface for it to be an effective alternative to the mouse (Anson, 1997).

Head-Controlled Mouse. For individuals who lack the hand or foot movement to operate a mouse or joystick, there are alternative pointing interfaces that are controlled with head movement (Evans, Drew, and Blenkhorn, 2000). In general, head-controlled mouse systems operate by using a tracking unit that senses and measures head posi- tion relative to a fixed reference point. This reference point is the center of the screen for the cursor. As the head moves away from this point in any direction, the cursor is moved on the screen. The technology that is used to sense the head movement differs from one system to another; it may be ultrasound, IR, gyroscopical, or image recognition (video). Each of these relies on transmission of a signal to the sensor on the user’s head and detection of a reflected signal that is sent back. An alternative approach is to locate a transmitter on the user’s head with a receiver that monitors the change in head position (Evans, Drew, and Blenkhorn, 2000). Different commercial systems imple- ment this reflective measurement in a variety of ways. In early versions of head-controlled interfaces, the headset worn by the user was connected with a wire to the com- puter, limiting the user’s mobility. Most of the systems cur- rently available have a wireless connection, which allows the user to move around more freely. Several devices require only a reflective dot to be placed on the user’s face (usually the forehead). This design eliminates the bulky head pointer used in earlier devices.

These systems are intended for individuals who lack upper extremity movement and who can accurately control head movement. For example, persons with high-level spinal cord injuries who cannot use any limb often find these head pointers to be rapid and easy to use. On the other hand, individuals who have random head movement or who do not have trunk alignment with the vertical axis of the video screen often have significantly more trouble using this type of input device.

In one common commercial approach, the user wears a sensor that is attached either to the forehead directly with adhesive, to a pair of glasses, or to a band or headset worn on the head (Figure 7-6, A ). Through the sensor, a tracking unit on the computer detects head movement and translates it into a signal that the computer interprets as if it were sent by a mouse. By moving the head (with the sensor on it), the person moves the cursor on the screen. For mouse-related tasks (e.g., selecting an icon, opening a window), the head- controlled interface is a direct replacement. Clicking and

double clicking are done by using either an acceptance (or dwell) time (which can be adjusted to meet the user’s needs) or a switch. When a switch is used, it is often a puff- and-sip switch that is attached directly to the headset. The person generates a single puff to click and two puffs to dou- ble click. To perform the drag function, the user must pro- duce sustained pressure on the puff switch. Some individuals may not have the breath control to perform the drag func- tion. In a later section software programs that can be used to replace the switch for drag-and-click functions are described. For typing, the head-controlled interface must be used with an on-screen keyboard program.

Control of the mouse cursor is either relative (like a joy- stick) or absolute (like a mouse). With absolute devices the mouse cursor position corresponds to the position of the device (e.g., a trackball, hand-operated mouse, etc.). To oper- ate a relative device, the person moves the cursor by displac- ing the control. When the cursor reaches the desired location, the control is released. The next movement is then made from that location by displacing the control again. A joystick is an example of a relative pointing device. Because a hand- operated mouse can also be lifted and repositioned, it can act like a relative device. Users with disabilities prefer the relative technique (Evans, Drew, and Blenkhorn, 2000).

Movement times for nondisabled individuals are greater for head-controlled cursor systems than for a conventional mouse (Radwin, Vanderheiden, and Lin, 1990). Movement times are also greater for small versus large targets and for far versus near targets in both healthy individuals and those with cerebral palsy. On the basis of reduction in average movement time as an indicator of relative learning, 15 sets of 48 trials (with one trial defined as mouse cursor move- ment from center screen to a randomly presented target) were sufficient to attain stable performance using both mouse and head-operated systems in nondisabled individuals. Two participants with cerebral palsy were included in this study. One participant’s learning approximated that of the nondisabled control subjects. The other participant’s learn- ing was more rapid but also more variable, and both speed and accuracy of head control were dramatically affected by proper trunk stability provided through a seating system.

User operational characteristics, including satisfaction, were evaluated for five currently available mouse alternatives that were based on head tracking by gathering the subjective evaluation of the users (Phillips and Lin, 2003). The users included individuals with high-level spinal cord injuries and those with cerebral palsy. Dependent variables were speed, accuracy, and distance or displacement in target acquisition tasks. Variable performance was reported for participants with cerebral palsy, even when identical interfaces were used. Words per minute and error rate for on-screen keyboards have also been used as dependent variables (Angelo, Deterding, and Weisman, 1991). For individuals with cerebral

250 C H A P T E R 7 Human/Assistive Technology Interface

palsy, direct target acquisition is a faster method than scan- ning (Angelo, 1992).

Three different technologies (IR with a reflective dot (Tracker 2000, Madentec, Ltd, Edmonton, Canada, www. Madentec.com), ultrasound (HeadMaster, Prentke Romich, Wooster, Ohio, www.prentrom.com), and gyroscopic (Tracer, Boost Technologies, www.boosttechnology.com) were com- pared in six nondisabled subjects (Anson et al, 2003). Comparisons of speed, accuracy, and user preference were made by using a drawing task with an on-screen cursor. Each of the three approaches was fastest for one third of the subjects and all were equally accurate. The preferred device was the Tracker 2000. This device has only a reflective dot attached to the head, whereas the other two had additional hardware attached. Although results for person with disabil- ities would likely differ, this study did indicate that all head pointing technologies can yield fast and accurate results.

The impact on performance of repeated trials of the head-controlled mouse (Madentec Tracker One (Madentec, Ltd) system was evaluated in a series of target acquisition tasks for 12 persons with cerebral palsy (Cook et al, 2005). Time to target, time to select, and distance moved to target (i.e., the screen distance traveled over the path between start and finish of a selection movement) were measured. The tar- gets were reduced in size across four once-weekly 1-hour sessions. Nine of the 12 participants were able to achieve a smaller target at the end of the session compared with the initial target size. For the same-size targets, six participants reduced their times to target and seven reduced the distance moved to acquire the target. However, only two participants showed a decrease in their time to select scores, which is an indication of the difficulty of holding a target for a preset dwell time. These results indicate that individuals with cere- bral palsy may be able to use head-controlled cursor systems if they are given sufficient practice time with a gradual reduction of target size as skill increases.

Comparison of Key-Pad and Head-Controlled Mouse Alternatives. When a consumer has difficulty in using the standard mouse, alternatives are considered and it is necessary to make comparisons between different alternatives. Generally, there is little empirical evidence to guide decision making. One study that is useful in this regard compared the use of a head-controlled mouse (Tracker 2000) and an expanded keyboard used as a key-pad mouse (Intellikeys, IntelliTools, Petaluma, Calif., www.intellitools.com) (Capilouto et al, 2005). These two devices were chosen because they both require gross motor movements and would likely be considered as alternatives for a specific consumer. The two devices were tested in a tar- get acquisition task by nondisabled university students. Each device was used to acquire a target by moving a cursor from a starting point in the center of the screen. The time to cap- ture a target decreased with practice for both devices, but the

head pointer resulted in faster performance. The time to acquire a target was longer for targets spaced further from the starting point, but this effect was less for the head- pointing device. Reaction time was less for the head point- ing device as well. All these results are related to the necessity for sequential action in the case of the keyboard (i.e., moving from one key to another to change mouse movement direction compared with continuous movement using the head-pointing system).

Light Pointers and Light Sensors. A visible light beam may be used as a pointing interface for direct selection. In a simple form the light can be pointed at objects in a room or at letters on a piece of paper. The effectiveness of the light pointer is directly related to how bright and focused it is, and this in turn affects size and weight. Light pointers are most commonly attached to a band worn on the head, but they can also be held in the hand. Highly focused light sources such as laser pens may cause damage if they are shined directly into the eye (Salamo and Jakobs, 1996). The reason for this is the same as the reason for their use: they are a source of highly focused light of high intensity. To illustrate the potential danger of the laser light source, Salamo and Jakobs (1996) compared a 0.001-watt (1 milliwatt) red-light laser with a 100-watt incandescent light bulb. Because the light bulb is not focused and emits light in all directions, the actual light bulb reaching the retina is about 1 milliwatt. Thus, the actual intensity on the retina is the same for both the light bulb and the laser event although the light bulb emits 100,000 times more light than the laser. Despite having the same energy at the retina, the potential danger from the laser is still greater than the light bulb because the size of the image on the eye is 10,000 times smaller (about 1 micrometer in diameter) than the image of the light bulb (about 1 millimeter in diameter), which spreads the heating over a larger area of the retina. This focus of the energy in a small area by the laser is what can lead to burning of the retina and permanent damage to the eye. One other factor that must be considered is the type and duration of exposure. Salamo and Jakobs (1996) recommend an exposure of less that 0.0004 milliwatts (0.4 microwatts) for 1 second as the limit for safe continuous exposure, as might occur in a classroom.

Lasers are grouped into five classes: I (<0.01 milliwatts), II (0.01 to 1 milliwatts), IIIa (1 to 5 milliwatts), IIIB (1 mil- liwatt to 0.5 watts), and IV (>0.5 watts) (Hyman, Miller, and Neigut, 1992). Only class I lasers meet this criteria; they are so dim that they are not visible in a brightly lit class- room. Laser pointers are at least class II. Because of the con- tinuous use, the possible limitation of protective reflexes that protect nondisabled individuals from exposure to class I laser and the uncontrolled environment the classroom, caution should be exercised when laser pointers are used for choice making and for indicating in the classroom.

P A R T III The Activities: General Purpose Assistive Technologies 251

IR (invisible) light sources can be used as pointers and computer input devices. A typical computer input system or communication device input consists of three components: (1) the IR transmitter (mounted on eyeglass frames), (2) an IR detector array, and (3) a controller that translates the received IR signals into computer commands corresponding to individual keyboard entries (Chen et al, 1999). Any num- ber of detectors can be used, but typically we use an array of light sensors, one for each element in the selection set. Then the light pointer is used to point to any element. An on-off switch and visible laser light source may also be included to allow greater independence of the user. For example, Chen et al used a tongue-activated switch to turn the system on and off and a visible low-power laser to serve as an indicator of where the user was pointing. They also provide design details on an IR pointing device for computer input. In clin- ical trials, users who had spinal cord injuries performed as well as users with no disabilities on the basis of speed and accuracy in selecting targets from the sensor array (Chen et al, 2004).

Modifications to Keyboards and Pointing Interfaces

There are several problems that may be experienced by indi- viduals with a physical disability in using any of the control interfaces just described. As mentioned earlier, if a consumer is having difficulty using a particular control interface, there are three paths to pursue. A control enhancer may resolve the difficulty (e.g., when the user has limited range for accessing the interface). Modification of the interface being evaluated is another alternative, and trying a less-limiting interface is the third approach. Before a less-limiting control interface is introduced, modification of the method being

evaluated should be considered. Table 7-10 lists the areas of need for which modification of a control interface may be beneficial and approaches that can be used. Each of these difficulties in using a keyboard can be addressed by either hardware or software modifications.

Keyboard Layouts. The QWERTY keyboard layout (Figure 7-12, A ), the one most familiar to people, was originally designed more than 100 years ago to slow down 10-finger typists using a manual typewriter so the keys would not jam. The QWERTY layout requires much excursion of the fingers and assumes that two hands with 10 fingers will be used. With an increasing number of indi- viduals using computers, there has been a substantial increase in repetitive strain injuries to the hand. Redefining the layout of the characters on the keyboard can reduce the amount of finger movements required by the user to access the keys and may reduce fatigue and the likelihood of an individual’s incurring a repetitive strain injury. Furthermore, there are alternative keyboard layout designs that have been developed to accelerate typing speed, such as when the individual is using only one hand or a mouthstick or another alternative access device. With computer key- boards, the definition of the keyboard layout is determined by software in the computer and the keys are labeled with the corresponding characters. The keyboard hardware (other than labeling of the keys) is not modified with any of the alternative keyboard layouts.

Developed in the 1930s by University of Washington Professor August Dvorak, the Dvorak keyboard layout was designed to reduce fatigue and increase speed by placing letters that are most frequently used on the home row of the keyboard. On the left side of the home row are all the vow- els, and five of the most used consonants are on the right side of the home row. There are three Dvorak keyboard lay- outs: one for two-handed typists (Figure 7-12, B), one for right hand–only typists (Figure 7-12, C), and one for left hand–only typists (similar to that shown for right hand–only typists but flipped). Information on how to redefine the computer keyboard as a Dvorak layout can be found at web.mit.edu/jcb/www/Dvorak/index.html.

The Chubon keyboard is a layout pattern that was designed to be used by the single-digit or typing-stick typist (Chubon and Hester, 1988). In this layout (Figure 7-12, D) the letters in the English language that are used most fre- quently are arranged near each other in the center. This lay- out also places letters that are most frequently used together (e.g., r and e) in close proximity, which reduces the amount of movement required by the user for entering text and helps to increase the rate of input. For individuals who use a mouthstick or typing stick, an alternative keyboard layout that reduces the amount of travel to keys can significantly increase efficiency.

252 C H A P T E R 7 Human/Assistive Technology Interface

Modifications to Keyboards and Pointing Interfaces

Need Addressed Approach

User’s speed not adequate for Modify keyboard layout, task prediction software macros, rate enhancement

software, word User has problems making Keyguard, template, shield, accurate selections delayed acceptance

User has difficulty holding Mechanical latch, software latch down the modifier key while pressing another key

User cannot release key Keyguard, careful selection of before it starts to repeat keyboard characteristics;

software to disable key repeat function

TABLE 7-10

Another alternative keyboard layout is an alphabetical array. Often individuals who are nonverbal and have been using a manual communication board to spell have learned to use an array in which the letters are placed in alphabeti- cal order. They are very familiar with this arrangement and may be very efficient in selecting characters. For these indi- viduals, it often does not make sense to have them learn a completely new letter arrangement. In this case the key- board can be redefined, by use of software, to have an alpha- betical arrangement.

When a keyboard pattern is selected, several factors need to be considered. The first factor to consider is whether the user is already familiar with one particular keyboard layout. If this is the case, it is important to keep in mind that the time needed for retraining to use a new keyboard pattern is estimated at 90 to 100 hours (Anson, 1997). Another factor to consider is whether the keyboard is shared with other individuals. It is possible to have the computer keyboard defined to use two keyboard patterns (e.g., QWERTY and Dvorak) and to label the keys so that the standard keys are not obscured (e.g., by use of a clear overlay with the new key labels on them, so when placed over the standard keys the original labels are still visible). However, this modification can be confusing to all typists. Finally, there are few data to support the claims that alternative keyboard patterns increase speed or reduce injury. Selecting an alternative key- board, like other technologies, depends on the needs and skills of the user and which layout he or she feels most com- fortable and efficient using.

Keyguards, Shields, and Templates. Some persons may be able to select individual keys directly, but they may occasionally miss the desired key and enter the wrong key. For individuals who have difficulty in accurately targeting and activating keys, a keyguard (Figure 7-20) placed over the keyboard helps by isolating each key and guiding the person’s movement. A keyguard is also useful for individuals who produce a lot of extraneous movement each time they

bring their hands off the keyboard in an attempt to target a new key. Instead of moving away from the keyboard to make the next selection, the person can rest the hand on top of the keyguard without activating any keys and make relatively isolated, controlled (and thus faster) selections. Although keyguards have been shown to increase the user’s accuracy, speed is typically compromised (McCormack, 1990). In nearly all situations a clear keyguard is preferred so that there is minimal obstruction of the labels on the keys. Still, the posi- tion of the keyboard with a keyguard needs to be assessed to ensure that the key labels are not being obstructed from the user’s view. Keyguards are commercially available for the common computer keyboards. In situations where an indi- vidual uses a special terminal in a work setting and would benefit from a keyguard, a custom keyguard can be fabricated from clear plastic.

Similar to the use of a keyguard is the use of a shield on the keyboard to block out certain keys. This modification is typically done with children who are just beginning to use computers and are using software programs that only require the use of a few select keys. To guide the child to the correct keys and increase his or her chances of success with the pro- gram, a shield is placed over the keys that are not being used.

A template used on a joystick to guide the individual’s movement is akin to the use of a keyguard for a keyboard. The template has four channels that guide the movement of the joystick. The shape of the channel may vary depending on the template and can be a factor in the individual’s abil- ity to control the joystick. For example, an individual using the cross-shaped template in Figure 7-21, A, may need more precise movement to enter the desired channel but once in one of these channels will be able to stay easily. If the tem- plate is like the one in Figure 7-21, B, it will be easy for the individual to enter one of the channels but difficult to stay. A compromise solution is to use a template similar to the one shown in Figure 7-21, C. In this case, because the entrance to each arm of the cross has been widened, it is eas- ier to move in each direction. Because the end of the slot in

P A R T III The Activities: General Purpose Assistive Technologies 253

Figure 7-20 Keyguard. (Courtesy TASH, Ajax, Ontario, Canada.)

each direction retains the cross shape, it is easier to keep the joystick in one direction. We can also improve the perform- ance of the star template (Figure 7-21, B) by restricting the travel at the end of the channel once the movement has been made in a direction. This change is shown in Figure 7-21, D. For some individuals, the use and type of joystick template means the difference between success or failure in the oper- ation of a power wheelchair.

Technologies for Reducing Accidental Entries. Many keyboards produce multiple entries of characters by prolonged pressing of the key called key repeat. Although this feature is useful to nondisabled users (e.g., to obtain multiple spaces or underlines), it can present a problem for persons with disabilities who may not be able to release the key fast enough to prevent double entry. There are a number of ways this can be avoided. Certain types and sensitivities of key- boards that may increase or decrease double entries and audi- tory feedback (e.g., a beep) when a key is activated may also cue the user to release the key in a timely manner. Both these are sensory characteristics of control interfaces, described earlier in this chapter, that need to be considered as part of the overall assessment. Sometimes the presence of a keyguard helps to diminish the double entries. If the double entries remain a problem, FilterKeys can be used (see Table 7-1).

CONTROL INTERFACES FOR INDIRECT SELECTION

When an individual’s physical control does not permit him or her to select directly, indirect selection methods are con- sidered. Indirect methods of selection use a single switch or an array of switches and require that the consumer be able to carry out a certain set of skills. Box 7-5 shows the critical

questions to pose during the evaluation to determine whether the consumer has the basic set of skills for switch use.

During the evaluation, it is first necessary to determine whether the user can activate the switch, which determines whether there is a match between the sensory, spatial, and activation (e.g., force) requirements of the switch and the physical-sensory skills of the user. If activation is possible, it is necessary to look at other skills related to the way the switch is to be used for indirect selection. The first of these is whether the consumer can wait for the desired selection to be presented. This task requires that the consumer have sensory skills for awareness of the selections being pre- sented. Depending on the consumer’s sensory abilities, selections can be presented visually or auditorily. An inabil- ity to wait can result from problems with central processing or motor control. If the consumer is having difficulty wait- ing, determining the underlying cause (i.e., sensory, central processing, or motor) may make it possible to modify the task, although the cause is not always easy to determine. The consumer must also be able to reliably activate the switch at the right time (i.e., when the desired selection is presented).

Another critical condition is that the consumer be able to hold a switch in its closed position for the time it takes the signal from the control interface to register. This time is a variable of the control interface and may differ from switch to switch. In addition, applications such as Morse code input, inverse scanning, and wheelchair mobility require the user to hold the switch closed. Within each of these appli- cations, the length of this hold time varies. For example, for the person using one-switch Morse code, the hold time varies from shorter to longer depending on the input signal (dot or dash). Inverse scanning (see next section) and wheel- chair mobility are other applications that require the user to hold down the switch for varying lengths of time. With inverse scanning, the switch is held until the right choice appears; for wheelchair mobility, the switch is held down until the user wants the chair to stop. Frustration, embar- rassment, and possibly serious injury in the case of mobility can result if the user cannot carry out precise holding of the switch. If the consumer is having difficulty activating or holding the switch, the switch may require too much force or displacement for activation or the sensory feedback

254 C H A P T E R 7 Human/Assistive Technology Interface

C D

BA

Figure 7-21 A to D, Four different shapes of joystick templates to maximize user’s skills.

BOX 7-5 Critical Questions for Evaluating Single-Switch and Switch-Array Use

1. Can the consumer activate the switch? 2. Can the consumer wait for the appropriate selection? 3. Can the consumer activate the switch at the right time? 4. Can the consumer maintain switch activation (hold)? 5. Can the consumer release on command? 6. Can the consumer repeatedly carry out the steps necessary

for selection?