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Developmental Neurorehabilitation

ISSN: 1751-8423 (Print) 1751-8431 (Online) Journal homepage: https://www.tandfonline.com/loi/ipdr20

Eye-gaze control technology for children, adolescents and adults with cerebral palsy with significant physical disability: Findings from a systematic review

Petra Karlsson, Abigail Allsop, Betty-Jean Dee-Price & Margaret Wallen

To cite this article: Petra Karlsson, Abigail Allsop, Betty-Jean Dee-Price & Margaret Wallen (2018) Eye-gaze control technology for children, adolescents and adults with cerebral palsy with significant physical disability: Findings from a systematic review, Developmental Neurorehabilitation, 21:8, 497-505, DOI: 10.1080/17518423.2017.1362057

To link to this article: https://doi.org/10.1080/17518423.2017.1362057

Published online: 01 Sep 2017.

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ORIGINAL ARTICLE

Eye-gaze control technology for children, adolescents and adults with cerebral palsy with significant physical disability: Findings from a systematic review Petra Karlssona, Abigail Allsopa, Betty-Jean Dee-Pricea,b, and Margaret Wallen a,c

aCerebral Palsy Alliance, The University of Sydney, Sydney, NSW, Australia; bSouthgate Institute for Health, Society and Equity, Flinders University, Adelaide, Australia; cAustralian Catholic University, Sydney, Australia

ABSTRACT Purpose: The primary objective of this systematic review was to examine the effectiveness of eye-gaze control technology for facilitating communication across different social contexts for people with cerebral palsy and significant physical disability. Methods: Systematic review. Results: The search identi- fied 756 potentially eligible articles, of which two, low level articles were eligible. One study reported positive results for achieving communication goals for children with cerebral palsy. The second con- cluded that eye-gaze control technology resulted in greater quality of life and less depression for adults with late stage amyotrophic lateral sclerosis when compared to non-users. Discussion: Research regard- ing the effectiveness of eye-gaze control technology used to access a laptop, tablet or computer on communication outcomes, participation, quality of life and self-esteem in children, adolescents and adults with cerebral palsy and significant physical disability is sparse. A scoping review to fully identify issues to inform clinical practice and future research is required.

ARTICLE HISTORY Received 23 April 2017 Revised 26 July 2017 Accepted 27 July 2017

KEYWORDS Assistive technology; communication; eye-gaze control technology

Introduction

Children and adults with cerebral palsy and significant phy- sical disability frequently have complex communication needs.1,2 One in four people with cerebral palsy is unable to talk and may benefit from access to computers for expressive communication.1

Movement disorders such as spasticity, dyskinesia and paresis which affect oromotor and respiratory muscle control result in difficulty speaking and being understood by commu- nication partners. Options for accessing alternative expressive communication, such as speech generating devices, are lim- ited when head and limb movements are also affected. Communication is a fundamental human right,3 enables peo- ple to develop and sustain interpersonal relationships4 and is critical for ensuring people are able to have their needs met.5

For people with significant physical disability, access to a computer enables communication, social participation and a range of other creative, leisure, and productive options.6 With a dedicated interface, an individual can access applications on a computer and control aspects of their environment, such as turning lights on and off, controlling air temperature, sum- moning assistance and changing channels and tracks on a TV or smartphone.7 Enabling people with significant physical disability to achieve the aforementioned outcomes could lead to enhanced quality of life and participation in life situations.

Eye-gaze control technology offers a means of accessing computers and speech generating devices for people with significant physical disabilities who have reliable voluntary

eye movements. It allows a person to engage with objects on a screen by moving only their eyes. The system involves a specialized infra-red video camera mounted on a tablet or personal computer. Nothing is attached to the user’s head or body. As the person sits in front of the eye-gaze control system, sophisticated image processing software analyses the camera’s image of the eye/s and determines where the user is looking on the screen. The computer tracks the eye move- ments, which in turn control the cursor on the screen. The person selects items either by holding their eye-gaze for a certain time, referred to as ‘dwell’, by blinking, or by clicking an external button. Eye-gaze control technology is a fast growing industry and more refined and robust hardware and software are constantly being revised and updated to cater to the access and communication needs of people with significant disabilities.8

Eye-gaze control technology is expensive and time con- suming to implement. Evidence is required to guide selection of appropriate potential users of eye-gaze control technology and to accurately match technology options with the user to optimize successful implementation and minimize device abandonment and resource waste. Little is published about effective implementation strategies or outcome measurement to ensure optimal resource utilization and user outcomes. The primary objective of this systematic review is, therefore, to examine the effectiveness of eye-gaze control technology for facilitating communication across different social contexts for children, adolescents and adults with complex communica- tion needs. The review was not restricted to evidence in cerebral palsy as we considered the body of evidence would

CONTACT Petra Karlsson [email protected] Cerebral Palsy Alliance, The University of Sydney, Australia, PO Box 6427, Sydney, NSW 2086, Australia.

DEVELOPMENTAL NEUROREHABILITATION 2018, VOL. 21, NO. 8, 497–505 https://doi.org/10.1080/17518423.2017.1362057

© 2018 Taylor & Francis

be small and that information obtained from other diagnostic groups would supplement our findings and inform practice in cerebral palsy.

The secondary objectives are to identify the impact of eye- gaze control technology on play, learning, education, work, leisure, participation, well-being, quality of life and self- esteem of eye-gaze control technology users and their com- munication partners.

Additional objectives are to identify, from included studies:

(i) Assessment strategies used to (a) guide implementa- tion and (b) measure outcomes of eye-gaze control technology to access a laptop, tablet or computer for children, adolescents and adults with significant phy- sical disability.

(ii) Strategies (for example, communication partner instruction, teaching/learning strategies for indivi- duals using eye-gaze control technology) used to implement eye-gaze control technology to access a laptop, tablet or computer for children, adolescents and adults with significant physical disability across different social contexts.

Methods

This systematic review included all levels of research evidence and aimed to integrate best practice systematic review methodology.

Search strategy

Based on preliminary searches and our existing knowledge of the field, few studies with people with cerebral palsy, which met the inclusion criteria, were expected. For this reason, and to ensure studies which included people with cerebral palsy as well as other diagnoses amongst the participants were not excluded, the search was expanded to include the use of eye- gaze control technology by people in other diagnostic groups with significant physical disability and complex communica- tion needs.

A search was performed across 11 databases during June 2016; CINAHL, Medline, Embase, ERIC, PsycINFO, speechBITE, PsycBITE, Scopus, OTseeker, Google Scholar and the Cochrane Library. The Population–Intervention– Comparison–Outcome (PICO) format was used to structure the search. A subject heading and key word search was con- ducted using the following terms to capture relevant popula- tions with motor impairment and studies of eye-gaze control technology. Population search terms included; ‘cerebral palsy’ OR ‘physical disab*’ OR ‘motor impair*’ OR ‘muscular dys- trophy’ OR ‘amyotrophic lateral sclerosis’ OR ‘ALS’ OR ‘motor neurone disease’ OR ‘stroke’ OR ‘locked in syndrome’ OR multiple sclerosis’ OR ‘motor disorder’ OR ‘developmen- tal disorder’ OR ‘brain injur*’ OR ‘quadriplegi*’ OR ‘physical impair*’ OR ‘complex communication’. These were combined with the following intervention terms; ‘eye gaze technology’ OR ‘eye gaze system’ OR ‘eye pointing technology’ OR ‘eye pointing system’ OR ‘eye tracking technology’ OR ‘eye

tracking system’ OR ‘eye control technology’ OR ‘eye control system’ OR ‘eye gaze control technology’ OR ‘eye-gaze control system’ OR ‘gaze based assistive technology’. The search strat- egy did not include comparison or outcome terms in order to capture all potentially relevant articles. There were no limits applied to the search. The Tobii eye-gaze resource (www. diigo.com/list/tobiieyetracking) and reference lists of relevant articles were hand searched.

Inclusion and exclusion criteria

All levels of primary research evidence, Oxford levels I to IV,9

case studies and single-case experimental design studies which reported data using an objective outcome measure were eligi- ble for inclusion. Studies reported in full-text, published in English in peer reviewed journals were eligible. Studies of children, adolescents or adults with a significant physical disability and complex communication needs who used eye- gaze control technology to access a computer, tablet or speech generating device were included. Studies were included if they measured: (a) the primary outcome of this review – commu- nication across different social contexts or (b) any of the secondary outcomes – play, learning, education, work, leisure, participation, quality of life, well-being or self-esteem of eye- gaze control technology users and their communication part- ners. Studies which exclusively measured the accuracy and technological properties of the devices or those which used eye-gaze to access low-tech communication systems were excluded. Grey literature and unpublished works were not eligible for inclusion. Qualitative research, conference publi- cations and Oxford level V evidence were also excluded.

Data extraction and evaluation

A single author conducted the search across the databases and produced a list of articles based on title and abstract according to the inclusion criteria. Two steps were carried out indepen- dently by two authors to identify articles for inclusion. The first step involved screening titles and abstracts for potential eligibility and, thereafter, screening the full-text of potentially eligible articles. Two authors independently completed data extraction and quality appraisal of eligible articles. No dis- agreements arose throughout this process to necessitate the involvement of a third reviewer.

It was not appropriate to conduct a meta-analysis or any statistical analyses of the results due to the small number and heterogeneity of the included studies. Instead, key informa- tion was summarized and presented narratively.

Quality assessment

The Oxford Centre for Evidence-Based Medicine (CEBM) Levels of Evidence9 was used to classify the type of study design of included studies. Risk of bias tools such as the Risk of Bias in Non-randomized Studies – of Interventions (ROBINS-I)10 was not appropriate given the low level study design of the included studies. Known study methodology and design principles were considered during data extraction and quality appraisal, and incorporated in the results and

498 P. KARLSSON ET AL.

conclusions of the review. These included: randomization of participants, blinding of assessors, sample size and justifica- tion, validity and reliability of outcome measures, adequacy of reporting and magnitude of results, description of the eye- gaze control technology and procedures used to implement the devices, and length of follow-up.

This review is registered with PROSPERO (International Prospective Register of Systematic Reviews; register number CRD42016035894).

Results

Search results

The search identified 756 potentially eligible articles. Following title and abstract review, 733 were excluded and three duplicates removed, leaving 20 articles which required full-text review. Two articles were subsequently identified as eligible for inclusion. This process is outlined in Figure 1. See the appendix for the list of 20 excluded studies and reasons for exclusion.

The included studies were Oxford Level 3 and 4 evidence,9

evaluating a range of outcomes in children with cerebral palsy and one child with spinal cord injury11 and adults with ALS.12

The outcomes included attainment of communication goals, frequency of computer use, quality of life, well-being and caregiver burden. Characteristics of the included studies are described in Table 1.

Study of children and adolescents with complex communication needs

Study description The study by Borgestig and colleagues11 from Sweden, included 10 children and adolescents (9 with cerebral palsy, 1 with cervical spinal cord injury) aged 1 to 15 years, who were introduced to eye-gaze control technology. The children with cerebral palsy had significant motor impairment, were non-ambulatory and had significantly impaired manual ability (see Table 1 for further classification of gross motor, manual ability and communication ability). Five children had unspe- cified cognitive impairment.

Nine children used the Tobii C12 and one used Tobii P10. Devices were mounted on a floor stand, table stand or wheel- chair and were portable.

Parents, a teacher for each child (communication partners) and children participated in fourteen days of intervention over a period of 9 to 10 months provided by a multi-profes- sional communication team. Outcomes were evaluated post- intervention and 5 to 10 months later. The intervention was a combination of group and individual sessions for both com- munication partners and children. The implementation pro- gram undertook to incorporate the devices into daily activities within the home and school environments.

Devices and mounting equipment were transported between home and school. Implementation in other environ- ments and the involvement of other communication partners such as peers, siblings and health care professionals were not discussed.

Primary outcome Direct measures of communication ability were not used in this study, however Borgestig and colleagues11 used Goal Attainment Scaling13 as a proxy measure of communication across different social contexts. The most frequently selected goals were: communication (20 goals); learning to use, or regular use of, eye-gaze control technology (13 goals); making choices (12 goals); interacting with others (7 goals) and completing school tasks (six goals). All chil- dren achieved one or more goals: 55% of goals were achieved by end of intervention and 60% by follow-up. Six of the seven (68%) goals related to interacting with others were achieved, 10 of the 13 (77%) learning to use or regular use of eye-gaze control technology goals, and half of each of the other goal categories were achieved. Approximately 60% of the 37 goals established for imple- mentation in schools and the 21 goals for home were achieved.

Total articles returned from databases.

Titles and abstracts screened (n = 756)

CINAHL = 5

Medline = 7

Embase = 30

ERIC = 1

PsycINFO = 9

speechBITE = 11

PsycBITE = 4

Scopus = 0

Google Scholar = 30

Tobii = 647

Cochrane =12

Total articles

following initial

screen by title and

abstract (n = 20)

Total articles

included following

full text review (n = 2)

Duplicates

removed (n = 3)

Ineligible (n = 733)

Articles excluded

following full-

text review

(n = 18) *

Figure 1. Flowchart of implementation of search strategy. *Reasons for exclusion are listed in the appendix.

DEVELOPMENTAL NEUROREHABILITATION 499

Table 1. Characteristics of included studies.

Borgestig et al., 2016 Hwang et al., 2014

Objectives To evaluate the impact of gaze-based assistive technology (AT) on daily activities for children with significant physical impairment.

To determine the effectiveness of eye-tracking assistive devices in improving quality of life, depression and caregiver burden for people with amyotrophic lateral sclerosis (ALS).

To evaluate parent satisfaction with the use of gaze-based AT services.

Study setting Regional pediatric rehabilitation center in Sweden with a multi- professional communication team specializing in AT.

Hospital setting (Taipei City Hospital and China Medical University Hospital in Taiwan).

Methods Design Multiple case study – before, after and follow-up design. Case-control study Level of evidence Oxford (CEBM) Level 4 evidence Oxford (CEBM) Level 3 evidence Inclusion criteria ● Severe physical impairment ● Late stage ALS with tetraplegia

● Unable to speak ● Unable to speak ● Up to 18 years of age ● Sufficient cognition to be able to express needs ● Access to gaze-based AT ● No useable limb or head movement

● Never used computer-assisted communication Exclusion criteria No exclusion criteria stated No exclusion criteria stated Follow-up points ● Baseline ● Baseline

● Post intervention (9–10 months from baseline) ● Post intervention (6 months from baseline) ● Follow-up at 5–10 months after end of intervention.

Participants Sample size N = 10 N = 20 people with ALS, “arbitrarily” divided into a user (of

eye-gaze control assistive device; n = 10) or non-user group (n = 10); also 20 careers of the people with ALS involved in the study.

Diagnosis Cerebral palsy: n = 9 Cervical spinal cord injury: n = 1 Severity classification for children with cerebral palsy

All participants had ALS for at least 2 years, used a phonetic communication board at time of study entry and were tracheostomy ventilated.

Gross Motor Function Classification System Level IV: n = 4, Level V: n = 5 Communication Function Classification System Level IV: n = 7, Level V: n = 2 Manual Ability Classification System Level IV: n = 4, Level V: n = 5 Movement disorder for children with cerebral palsy Dyskinesia: n = 4, spastic diplegia: n = 3, spastic tetraplegia: n = 2

Age Total group: range 1–15 years (M = 8.6, SD = 4.6) User group: range 40–66 years (M = 51.5, SD = 7.72) Cerebral palsy: range 5–15 years (M = 9.4, SD = 3.9) Non-user group: range 38–85 years (M = 58.2, SD = 11.6) Cervical spinal cord injury: 1 year User caregivers: range 27–82 years (M = 55.9; SD not given)

Non-user caregivers: range 38–62 years (M = 54.6; SD not given)

Gender Males = 8 Users = 4 males, 6 females Females = 2 Non-user = 9 males, 1 female

User caregivers = 4 male, 6 females Non-user caregivers = 2 males, 8 females

Intellectual disability 5 children had “unspecified cognitive impairment.” Enough cognitive ability to be able to communicate needs to careers.

Intervention Eye-gaze control technology Tobii C12 (n = 9) and P10 (n = 1).

Each device was adapted to meet the needs of each participant. Children were given access to gaze-based AT and related services for the duration of the study. The devices were mounted on floor stand, table stand or wheelchair and were transported between home and school.

Type not specified. Authors note that the device was provided by the company Spring Track/Utechzone. The technology was not portable. Positioning and mounting of the device were not specified. User group: used eye-gaze control technology for 6 months as well as continued use of phonetic board. Non-user group: continued use of phonetic board only.

Strategies used to assess suitability for eye-gaze control technology

No details were provided. No details were provided.

Implementation strategies: ● Group introduction and training provided over 2 days. ● No mention of training or instruction on the use of the devices. ● Course days provided for teachers and parents. ● Course day provided for children.

● The communication partners and the environments in which the devices were used were not specified.

● Individual planning and follow-up meetings. Communication partners and

contexts Parents and teachers in home and school environments. Not specified

Comparison interventions No comparison intervention. Continued use of phonetic board only.

Outcome measures (includes any ineligible outcomes which the study assessed)

Functional communication outcomes (primary):

Attainment of functional goals (goal attainment scaling (GAS)); established at baseline and reviewed at post intervention and follow-up.

No outcome measures in this category.

(Continued)

500 P. KARLSSON ET AL.

Secondary outcomes There were no eligible secondary outcomes addressed in Borgestig’s study,11 however, technology use was recorded and parents completed the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST 2.0)14 to measure satisfaction with eye-gaze control technology and services related to the tech- nology intervention. Immediately after intervention, parents reported high satisfaction for both domains, particularly service delivery. At follow-up 5 to 10 months later, satisfaction in both domains had decreased, particularly for satisfaction with service delivery. Item durability and comfort were the least satisfactory device related items. At final follow-up, fewer parents were satis- fied with repairs and servicing, and follow-up services.

All 10 participants completed computer activities at home and/or school at follow-up compared to five at baseline. The repertoire of activities increased from a mean of 1.8 at baseline to 3.8 at follow-up. The most frequent activity completed was to talk with another person at home or at school. Following inter- vention, seven children increased the number of activities per- formed per day, time spent performing activities per day and/or the percentage of days they used eye-gaze control technology. These increases were maintained at follow-up.

Adverse events: This study did not address the issue of adverse events.

Study of adults with ALS and complex communication needs

Study description Hwang and colleagues12 completed a case-control study in Taiwan of 20 adults, aged 40 to 66 years, with late-stage ALS and their primary caregivers. Consistent with our wide inclusion criteria, this study was considered eligible and potentially useful in inform- ing application of eye-gaze control technology for people with cerebral palsy. Sixteen of the 20 caregivers were spouses. The participants were tracheostomy ventilated, had no functional head or limb movement, were able to express their needs to a caregiver and were established users of a communication board. Participants were “arbitrarily” assigned to an experimental group, who were given eye-gaze control technology, or a control group.

Participants in both groups continued to use a communication board. Outcomes were evaluated after 6 months.

Hwang and colleagues12 reported the device supplier but the make and model were not specified. No details were given of implementation, for instance, mounting devices. Devices were reported as too bulky to move with the wheelchair. Likewise, no details were given about the education that was provided to users, and whether communication partners were provided with instruction. Little information was given about what the computer was used for, except for accessing the internet and sending emails.

Forty percent of participants in Hwang et al.’s study12 used eye-gaze control technology for 1 to 3 hours per day, 40% for 3 to 5 hours per day, and 20% of participants used the device for 5 to 8 hours per day. The authors noted that participants took only a few days to become completely familiar with the device and computer, and that the systems were costly.

Primary outcome The study by Hwang and colleagues12 did not measure com- munication outcomes.

Secondary outcomes Quality of life. Participants using eye-gaze control technology12 had statistically significantly higher quality of life (total score and three of six domains) than the non-user group at follow-up as measured on the Revised ALS Specific Quality of Life Instrument.

Well-being. Participants using eye-gaze control technology12

had significantly less depression, at follow-up, on the total score and two of three domains of the Taiwanese Depression Questionnaire than the non-user group.

Caregiver burden. At follow-up, caregivers of eye-gaze con- trol technology users experienced significantly less caregiver burden than caregivers of non-users, on the total score and two of four domains of the Caregiver Burden Scale.

Adverse events. This study did not address the issue of adverse events.

Table 1. (Continued).

Borgestig et al., 2016 Hwang et al., 2014

Secondary outcome measures: ● Parent satisfaction with technology and services (The Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST 2.0)); completed at post-intervention and follow-up.

● Computer use diary which recorded type and duration of computer activities.

● Quality of life (Revised ALS-Specific Quality of Life Instrument)

● Caregiver burden (The Caregiver Burden Scale) ● Severity of Depression (Taiwanese Depression Questionnaire)

Results and conclusions GAS: All children achieved at least one goal. Most children achieved 3–4 goals.

Quality of Life: Significantly higher quality of life scores for user group compared to non-user group (p < 0.001)

Goals most frequently included communication (20), learning to use/regular use of AT (13), make choices (12), do school tasks (6).

Caregiver burden: Significantly lower caregiver burden in user group compared to non-user group (p < 0.05).

QUEST 2.0: High parent satisfaction associated with use of technology and services at post-intervention. Reduction in satisfaction observed at follow-up, likely due to withdrawal of services.

Severity of Depression: Significantly less depression for user group compared to non-user group (p < 0.001).

Notes on methodological ● No comparison group. ● Data not presented for all domains of the outcome measures. quality. e.g. sample size

justification, blinded assessors.

● No blinding of assessors. Unable to blind clinicians or children and families. ● Small, unjustified sample size.

● Non-user group appeared to have a higher level of education.

● Participants were arbitrarily assigned to groups.

DEVELOPMENTAL NEUROREHABILITATION 501

Discussion

This review aimed to identify the effectiveness of eye-gaze control technology for facilitating communication and other, secondary, outcomes for children and adults with cerebral palsy and signifi- cant disability. Even when our search strategy and inclusion cri- teria enabled inclusion of research completed in other diagnostic groups to inform practice in cerebral palsy, only two eligible studies were located. Borgestig’s study11 of children with signifi- cant disability used Goal Attainment Scaling as a proxy measure of communication. They concluded that use of computers increased and all children had attained goals which included those related to communication. Hwang’s research12 with adults with late-stage ALS did not measure communication but reported positive results in secondary outcomes of interest in this review. Users of eye-gaze control technology had greater quality of life and lower levels of depression than a non-user group. Their primary caregivers, mainly spouses, also reported lesscaregiver burden than caregivers of non-users. These are clearly important outcomes for people at end of life and potentially related to enhanced ability to commu- nicate needs, exercise choice, maintain relationships and sustain social participation. Both studies were low CEBM levels of evi- dence (Levels 312 and 411) and therefore the conclusions drawn, although promising, should be treated cautiously.

The impact of cognitive and intellectual disability on the capa- city to use eye-gaze control technology is not clearly known. On the other hand, it is difficult to assess cognitive or intellectual impairment in people with significant motor and communication difficulties. Participants in Hwang et al.’s study12 were able to express their needs and each one successfully used the technology. Several of the children in Borgestig’s study11 had cognitive impair- ment and all learned to use eye-gaze control technology to some extent. Future research to develop means to screen or assess intellectual impairment and to understand its impact on use of eye-gaze control technology for communication and other pur- poses is a high priority.

The eligible studies did not address assessment strategies used to guide implementation of eye-gaze control technology. An assumption is generally made that people with significant motor disability should be given the opportunity to use an alternative form of communication and that eye-gaze control technology may be the only option available. Trialing this technology is, therefore, a responsible action. Screening pro- cedures to provide direction for clinicians and clients in selecting appropriate systems for trialing would be useful to streamline the phase during which trialing of devices takes place and maximizes the likelihood of a well-suited system being purchased.

Abandonment of assistive technology is an acknowledged phenomenon resulting, in part, from ill-suited devices and insufficient support given to users and their communication partners. Communication partner instruction is effective for teaching skills to communication partners to increase social interactions of children with cerebral palsy15 and potentially reduce the risk of device abandonment. A team based approach, as recommended by previous research,16,17 was adopted by Borgestig et al.11 to support parents and teachers throughout the assistive technology device implementation process. The intervention program, delivered over a

9–10 month period providing instructional days for the child using the device as well as for the child’s parents and teachers, aiming to incorporate the devices into daily activities in both home and school environments. Child and family goals were achieved in both environments, supporting the approach used. Borgestig et al.11 found that parents reported high levels of satisfaction with service delivery immediately following the intervention period but satisfaction levels declined markedly at follow-up, 5–10 months later. These findings suggest that, despite training and support during a long implementation phase, on-going review and follow-up may be required to adapt and expand eye-gaze tasks to match increased skill development and changing demands on the user over time18 Given the skill required to support a user, consideration needs to be given to customizing communica- tion partner instruction to an individual user’s specific con- texts and environments. For instance, research has indicated that educating children’s class mates and educational assis- tants also assists in promoting social communication.19–21 No mention was made in Hwang’s study of how technology was implemented, the environments in which it was used or of communication partner or user instruction strategies.

Communication partner instruction is one means of facil- itating a supportive social environment in which to implement eye-gaze control technology. Other social environmental facil- itators may include normalizing technology in daily life, pro- moting acceptance of diversity and optimizing the attitudes and acceptance of the community (e.g. people in schools/pre- schools, workplaces, churches, leisure and recreation settings) towards people with disability and particularly those with whom it is difficult to communicate. Finally, explicitly addres- sing aspects of the physical environment will assist in imple- mentation and sustained use of eye-gaze control technology. Specialized seating and positioning, effective mounting for eye- gaze control technology devices and ability to be portable will enable people with significant disabilities to effectively access their technology in a range of physical and social environments and therefore enhance social participation.

A final objective of this review was to identify tools to measure outcomes of eye-gaze control technology implemen- tation in clinical practice and future research. Of note, a direct measure of communication was not used in either study. Individuals with significant disability will have unique and complex communication goals. Examples include those as simple as indicating yes/no or other short response sequences, or as advanced as accessing social media, emails and the internet by generating written text, and operating speech generating devices. Other individualized and important goals for eye-gaze control access of technology are for games and leisure, education, and controlling air conditioning, music, television and other physical aspects of the environment. These unique requirements may best be evaluated by measur- ing goal attainment using tools such as Goal Attainment Scaling13 and the Individually Prioritized Problem Assessment.22 Furthermore, children with cerebral palsy and significant physical disability are less likely to have had suffi- cient exposure to learning and teaching opportunities for developing literacy skills at an early age. Communication, for these children, will not be using traditional written text

502 P. KARLSSON ET AL.

generated by computer, at least in the early years of their school life. These unique aspects of development require consideration when selecting outcome measures to evaluate the outcomes of eye-gaze control technology for young children.

Apart from the measure of satisfaction used by Borgestig (QUEST 2.0), neither of the studies included in this review used outcomes specific to eye-gaze control technology or assistive tech- nology. This is perhaps not surprising given that the studies focused on a type of technology that is somewhat new to the field and may provide challenges to evaluate. Of note, is that a literature review, published in 2013 and aiming to identify and appraise methods of measuring outcomes in relation to augmen- tative and alternative communication (AAC), found no measures specifically developed for use with AAC.23 The authors identified two possible instruments, Therapy Outcome Measure (TOM)24

and C.O.D.E.S (Competency, Opportunity, Driving communica- tion forward, Engagement and Skill acquisition) framework devel- oped for children25 that had the potential, following further development, to assess the person’s AAC skills, provide guidance on interventions and measure change following intervention. Since then, AAC TOMs27 have been developed. It is freely avail- able and is aligned with the International Classification of Functioning – Children and Youth.26 AAC TOMs are completed at three time points, in conjunction with assessment, during intervention and at follow-up after intervention. Four broad areas are evaluated: Impairment, Activity, Participation and Well-being,27 which include rating ability on areas such as com- munication; social, occupational and family participation; and well-being.

A family-centered framework which involves understand- ing family needs and preferences and supporting families to implement complex interventions such as assistive technology and AAC is necessary for successful implementation.28 An additional tool to assist health professionals in this endeavor is the Family Impact of Assistive Technology Scale for AAC systems (FIATS-AAC). This parent-report questionnaire identifies areas where family members may need particular support for implementing AAC and measures the outcome of assistive technology for the child and different communica- tion partners and family members.29,30

Finally, in relation to outcome measurement, measures of participation and quality of life should be explored to identify whether successful eye-gaze control technology used to access a computer has an impact on these important domains.

Several factors are likely to contribute to the paucity of research regarding outcomes of eye-gaze control technology.31

The field is relatively new for people with disabilities and it takes time to build a body of good quality research. The equipment required is expensive and therefore costs can be inhibitive. In addition, extended follow-up, which adds to costs, is necessary to identify effective ways of sustaining effects and responding to increased skills, changing needs of a user over time and advancements in technology. There are relatively small numbers of users and implementing eye-gaze control technology is highly individualized, including the physical and intellectual abilities of the user, the purposes for which the technology is required, the type of hardware and software which will be appropriate and the nature of

outcomes to be measured. Identifying a homogenous group of participants participating in a uniform intervention is, therefore, difficult, as is the ethical dilemma of withholding an intervention from a control group for whom a successful intervention could be life-changing. As for evaluation of most assistive technology and AAC devices, eye-gaze control tech- nology is a complex intervention and as such requires inno- vative and probably a research design with multiple stages to comprehensively evaluate outcomes in a meaningful way.16

Limitations

This review identified only two low level studies for inclusion in this review. Differences in study participants’ diagnoses, ages, interventions and outcome measures precluded any pooling or generalization of results. Inclusion of Level 5 evidence and qualitative research would have provided a richer overview of the area and additional direction for clin- ical practice and designing future studies.

Conclusion

AAC plays a critical role in supporting communication, play, education, work, leisure and participation of people with cerebral palsy and other significant physical disability. For some, eye-gaze control technology may be the only way of optimizing independent communication and activity. Given the potential for eye-gaze control technology to make a sub- stantial impact on the lives of people with significant disabil- ity, there is little research to guide assessment for optimal configurations of hardware and software technology, training of users and their communication partners. Likewise, there is no research using direct measures of communication to eval- uate outcomes of eye-gaze control technology for people with significant disability. Finally, there is minimal evidence for effectiveness of systems for increasing communication, lei- sure, creativity, productivity or quality of life across all of the user’s environments. The existing research provides weak evidence supporting the positive impact of eye-gaze control technology for children with cerebral palsy and adults with late-stage ALS. A scoping review of all available literature regarding eye-gaze control technology is recommended to provide a deeper understanding of the breadth of issues involved in this important area of practice, including incor- poration of this technology into broader social and physical environmental contexts. Future work may also compare and contrast other technologies to assist in identifying appropriate systems for individual users. Research is urgently required to support ongoing funding for eye-gaze control technology and inform clinical practice about when and how it can be intro- duced for people with severe motor disabilities and complex communication needs.

Acknowledgements

The authors would like to warmly thank Claire Galea, Statistician at Cerebral Palsy Alliance, for her advice regarding methodological aspects of this review.

DEVELOPMENTAL NEUROREHABILITATION 503

Declaration of interest

The authors declare no conflicts of interest.

ORCID

Margaret Wallen http://orcid.org/0000-0002-8040-5053

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Appendix

Table of excluded studies.

Article Reason for exclusion

1. Amantis R, Corradi F, Molteni AM, Massara B, Orlandi M, Federici S, Mele ML. Eye-tracking assistive technology: is this effective for the developmental age? Evaluation of eye- tracking systems for children and adolescents with cerebral palsy. Assistive Technology Research Series 2011;29:489-496.

Did not address the primary and secondary outcomes (measured accuracy and technological properties of the devices)

2. Caligari M, Godi M, Guglielmetti S, Franchignoni F, Nardone A. Eye tracking communication devices in amyotrophic lateral sclerosis: Impact on disability and quality of life. Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration 2013;14(7-8):546- 552.

Not an eligible study design (survey design)

3. Calvo A, Pasian V, Moglia C, Balma M, Montuschi A, Corno F, Chio A. Eye-tracking communication system: Impact on quality of life and mood in patients with ALS in locked- in syndrome. Amyotrophic Lateral Sclerosis 2009;10:201-202

Not full text article (conference publication)

4. Donegan M, Morris JD, Corno F, Signorile I, Chió A, Pasian V, Vignola A, Buchholz M, Holmqvist E. Understanding users and their needs. Universal Access in the Information Society 2009;8(4):259.

Insufficient information on objective outcome measures.

5. Donegan M. Participatory design: The story of Jayne and other complex cases. In Majaranta P, Aoki H, Donegan M, Hansen DW, Hansen JP, Hyrskykari A, Räihä K (Eds). Gaze Interaction and Applications of Eye Tracking: Advances in Assistive Technologies (pp. 55– 61), 2012.

Not published in peer reviewed journal (book chapter)

6. Cham E, Poirier B. Satisfaction of ALS clients and caregivers with training on use of an eye- gaze system in a facility setting. Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration 2013;14:81-82

Not full text article (conference publication)

7. Federici S, Borsci S. Providing assistive technology in Italy: the perceived delivery process quality as affecting abandonment. Disability and Rehabilitation: Assistive Technology 2016;11(1):22-31.

Did not address the primary or secondary outcomes

8. Giacone S, Ilardi A, Pasian V, Moglia C, Balma M, Montuschi A, Corno F, Calvo A, Gallo S, Canosa A, Chio A. Can eye-tracking system communication improve quality of life and mood in ALS patients with locked-in syndrome? Journal of Neurology 2010;257(S-1):S113.

Not full text article (conference publication)

9. Harris D, Goren M. The ERICA eye gaze system versus manual letter board to aid communication in ALS/MND. British Journal of Neuroscience Nursing 2009;5(5).

Did not address primary or secondary outcomes (measured speed of use)

10. Holmqvist E. Assessment and introduction of computer eye gaze systems for children with severe motor disabilities: a clinical experience. Developmental Medicine & Child Neurology 2011;53:65.

Not full text article (conference publication)

11. Lancioni GE, Singh NN, O’Reilly MF, Sigafoos J, D’Amico F, Addante LM, Ferlisi G, Zullo V, Oliva D, Megna M. Technology to help persons with extensive neuro-motor impairment and lack of speech with their leisure occupation and communication. Research in Developmental Disabilities 2014;35(3):611-618.

Did not address primary or secondary outcomes

12. Lariviere JA. Eye tracking: eye-gaze technology. In International handbook of occupational therapy interventions 2015 (pp. 339-362). Springer International Publishing.

Not full text article (book chapter)

13. Man DW, Wong MS. Evaluation of computer-access solutions for students with quadriplegic athetoid cerebral palsy. American Journal of Occupational Therapy 2007;61 (3):355-364.

Did not address the primary or secondary outcomes (measured accuracy and technological properties of the devices)

14. Pessia A, Ilardi A, Pasian V, Moglia C, Giacone S, Cammarosano S, Montuschi A, Canosa A, Gallo S, Calvo A, Corno F. Use of eye-tracking system communication in ALS patients: positive impact on quality of life and mood. European Journal of Neurology 2010;17:303.

Not full text article (conference publication)

15. Kang SH, Kim DK, Seo KM, Choi KN, Yoo JY, Sung SY, Park HJ. A computerized visual perception rehabilitation programme with interactive computer interface using motion tracking technology—a randomized controlled, single-blinded, pilot clinical trial study. Clinical rehabilitation 2009;23(5):434-444.

Did not address primary or secondary outcomes

16. Spataro R, Manno C, Ciriacono M, La Bella V. Eye-tracking computer system utilization by patients with advanced amyotrophic lateral sclerosis. Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration 2013;14:suppl 2:64-83.

Not full text article (conference publication)

17. Van Niekerk K, Tönsing K. Eye gaze technology: A South African perspective. Disability and Rehabilitation: Assistive Technology 2015;10(4):340-346.

Not included study design (case studies)

18. Wright A, Clarke C. A comparison of eye-gaze communication systems and a protocol for assessment. Amyotrophic Lateral Sclerosis 2009;10:suppl 1:191-205.

Protocol for research

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