Article review
Therealdeal00
VanDerMeer26Rispoli2C2010.pdf
informa healthcare Developmental Neurorehabilitation, August 2010; 13(4): 294–306
SUBJECT REVIEW
Communication interventions involving speech-generating devices for children with autism: A review of the literature
LARAH A. J. VAN DER MEER1 & MANDY RISPOLI2
1 Victoria University of Wellington, Wellington, New Zealand and 2Texas A & M University, College Station, TX, USA
(Received 1 February 2010; accepted 1 February 2010)
Abstract Objective: The current review synthesizes communication intervention studies that involved the use of speech-generating devices (SGD) for children with autism. Methods: Twenty-three studies were identified that met the inclusion criteria following systematic searches of electronic databases, journals and reference lists. Studies were evaluated in terms of: (a) participants, (b) setting, (c) mode of communication, (d) communication skill(s) taught to the participant, (e) intervention procedures, (f) outcomes, (g) follow-up and generalization, (h) reliability and treatment integrity and (i) design and certainty of evidence. Results: Intervention, most commonly targeting requesting skills, was provided to a total of 51 children aged 3–16 years. Intervention strategies followed two main approaches: operant/behavioural techniques and naturalistic teaching procedures. Positive outcomes were reported for 86% of the studies and 78% of the studies were categorized as providing conclusive evidence. Conclusion: The literature base suggests that SGDs are viable communication options for children with autism. However, several areas warrant future research.
Keywords: autism, ASD, speech generating device, voice-output communication aid, communication, intervention
Resumen Objetivo: La actual revisión sintetiza los estudios sobre intervenciones de comunicación que utilizan dispositivos de generación del habla (SGD) para niños con autismo. Métodos: Posterior a una búsqueda sistematizada de listas de referencias, revistas y bases de datos electrónicas se identificaron veintitrés estudios que cumplı́an con los criterios de inclusión. Los estudios fueron evaluados en términos de: (a) participantes, (b) escenario, (c) medio de comunicación, (d) habilidad(es) de comunicación enseñadas a los participantes,
˜ os con autismo. Sin
´n de producción de la voz,
stereotyped behaviour patterns [1]. Up to half of autism do not develop speech or
develop only limited speech and language abilities these children may rely on
behaviours, including pointing,
(e) procedimiento de intervención, (f) resultados, (g) seguimiento y generalización, (h) integridad y confiabilidad del tratamiento y (i) diseño y certeza de la evidencia. Resultados: Se proporcionó intervención, con mayor interés en las habilidades de petición, a un total de 51 niños con edades comprendidas entre los 3 y los 16 años de edad. Las estrategias de intervención siguieron dos enfoques principalmente: técnicas operantes/conductuales y el enfoque de enseñanza naturalista. Se reportaron resultados positivos en el 86% de los estudios y el 78% de los estudios se categorizaron como aportadores de pruebas concluyente. Conclusión: Esta literatura de base sugiere que los SGD son una opción viable de comunicación para nin embargo, múltiples áreas ameritan una mayor investigación.
Palabras clave: autismo, ASD, dispositivos de generación del habla, dispositivo de ayuda de comunicacio comunicación, intervención
Introduction
Individuals with Autism Spectrum Disorders (ASD) children with are characterized by having significant impairments in social interaction, communication development [2–6]. Instead and the presence of restricted, repetitive and pre-linguistic
Correspondence: Larah van der Meer, School of Educational Psychology, Victoria University of Wellington, PO Box 17-310, Karori 6147, Wellington, New Zealand. E-mail: [email protected]
ISSN 1751–8423 print/ISSN 1751–8431 online/10/040294–13 � 2010 Informa UK Ltd. DOI: 10.3109/17518421003671494
reaching, eye-gazing and other facial expressions [7, 8]. Some children may also demonstrate challenging behaviour, such as aggression, tantrums and self-injury in an attempt to communicate their wants and needs [9, 10]. Such pre-linguistic behaviours become frustrating for both the commu- nicator and the communication partner, as they are often difficult to interpret.
Romski et al. [11] explained that it is unclear whether children who lack speech at a young age will remain at this pre-linguistic level. Instead the child’s communication status may change over time as a function of maturity, intervention or both. One intervention that these children may benefit from is augmentative and alternative communication (AAC). AAC refers to a practice that aims to supplement (i.e. augment) or replace (i.e. alternative) natural speech [12–15]. This is achieved either by unaided approaches, such as gestures or manual signing; or by aided systems, involving graphics (traditional orthography, photographs or line drawings). Aided systems use external equipment with a communicative function, such as Picture Exchange (PE) [16, 17] or Speech-Generating Devices (SGDs), otherwise referred to as voice output communication aids (VOCAs) [18].
In particular SGDs became prominent communi- cation options for many individuals with autism by the 1980s and 1990s [19, 20]. A SGD is a portable electronic devise that will produce either digitized or synthesized speech output. The SGD displays a variety of graphic symbols to represent a message that is activated resulting in voice output when the individual uses a finger, hand or some other means to select the message [7].
To date SGD intervention research has typically involved teaching the individual to request access to highly preferred items [18, 21]. For example, in a SGD intervention the individual might be taught to touch a picture or line drawing on the electronic speech output device, which produces a pre- recorded message, such as ‘I want __’. In return the communication partner will deliver the requested item [22]. In addition to requesting, a number of other communicative functions, such as comment- ing, greeting or answering questions would be important to teach to individuals with ASD [23]. Most of these communication skills have been taught within a positivist behaviour analytic approach using operant methods such as discrete trial training [24]. However, recently naturalistic approaches to teach- ing SGD use have been increasing [25].
Depending on communicative goals, a large variety of SGDs can be selected and customized for inter- vention. SGDs can vary in design including perma- nence of the display (static or dynamic), number of graphic representations on the display and size of the
Communication interventions 295
graphic symbols [26]. Consideration of the type of voice-output used (digitized vs synthesized) can also be important. For example, it has been hypothesized that the lack of variability and robotic nature of synthesized speech may need to be considered when implementing AAC with individuals with autism [27]. The voice-output feature of SGDs might also make this a more readily understood mode of communication, thus promoting greater community inclusion and participation [28].
An emerging corpus of intervention research has investigated the use of SGDs as well as AAC in general with individuals with developmental disabilities or autism and there are several reviews that have focused on a number of issues related to this topic [7, 18, 19, 27, 29, 30]. Schlosser and Lee [29], for example, provide support for the use of AAC in general, but did not focus on individual modalities of AAC, such as SGDs. Lancioni et al. [18] focused on the use of SGDs and PECs in teaching requesting behaviours to individuals with developmental disabilities. They concluded that outcomes are encouraging, but methodological concerns provide reason for results to be interpreted with caution. Only Schlosser et al. [19] appear to specifically review research assessing the use of SGDs for individuals with autism. Thus, in order to answer empirical questions that remain in this field [31], a systematic review of SGD interventions with individuals with autism is warranted. The aim of the current report is to systematically review the litera- ture in this field and thereby evaluate whether there is evidence to support that children with autism are capable of learning to use an SGD to communicate. Specific objectives are to provide an up-to-date synthesis of the literature in order to (a) assist clinicians in their practice of improving the commu- nication of children with autism and (b) identify gaps in the literature and areas in need of further research. Together these objectives may help to guide and inform evidence-based practice with respect to the use of SGDs in communication interventions for children with autism.
Method
Search procedures
Systematic searches were conducted in six electronic databases: Cumulative Index of Nursing and Allied Health Literatures (CINAHL), Education Resources Information Center (ERIC), Medline, Linguistics and Language Behavior Abstracts (LLBA), Proquest and PsycINFO. Publication year was not restricted, but the search was limited to English-language journal articles. The search covered all dates covered by these databases up to September 2009.
296 L. A. J. van der Meer & M. Rispoli
For the CINAHL search, voice-output communi- cation aid (or speech-generating device) and autism was entered into the All Text field. For the remaining databases, the free-text terms voice-output commu- nication aid (or VOCA or speech-generating device) and autism (or autism spectrum disorders) were inserted into the Keywords field. Abstracts of the records returned from these electronic searches were reviewed to identify studies for inclusion in the review (see Inclusion and Exclusion Criteria).
Three additional search strategies were used in order to find other possibly relevant studies that may have been missed by the electronic search. First, the reference lists for the included studies were reviewed to identify additional articles for possible inclusion. Secondly, hand searches were completed for the journals that had published the included studies. Finally, using an author search, the five databases were searched again for additional related work by authors of the studies that met the inclusion criteria. From this combination of search procedures, 25 articles were identified for possible inclusion in the systematic review.
Inclusion and exclusion criteria
To be included in this review, the article had to be a research study that included children (518 years of age) with ASD and examined the effects of an intervention involving SGDs. Intervention was defined as implementing one or more therapeutic/ teaching procedures for the purpose of trying to increase or improve the child’s communication skills or abilities through the use of a SGD. Examples could include teaching a child to use an SGD to (a) make requests, (b) spell words or (c) repair a communicative breakdown.
The research study had to obtain empirical data from which one could assess the success of the intervention. For example, a paper by Light et al. [32] initially identified for inclusion used case reports that did not provide objective data on SGD use and was therefore not included in the current review. Studies that focused only on the description of or assessment of communication skills were not included.
Data extraction
Each study identified was first evaluated to establish if it met the pre-determined inclusion criteria. All studies that met the inclusion criteria were then coded in terms of: (a) participants (e.g. age, gender, number and diagnosis), (b) setting (e.g. school, home or community setting), (c) mode of commu- nication (e.g. type of SGD used), (d) communica- tion skill(s) taught to the participant, (e) intervention procedures (e.g. least to most prompting), (f)
outcomes of the intervention, (g) follow-up and generalization, if any, (h) reliability and treatment integrity and (i) experimental design and certainty of evidence. The certainty of evidence was rated as either conclusive or inconclusive [33, 34] in order to provide an overview of the quality of the evidence across the studies reviewed [35].
Inter-rater agreement
The initial search of the six databases revealed 15 articles that met the inclusion criteria for this review. Three articles were identified in the reference list search; three articles were identified in the journal search and finally three articles were identi- fied in the author search, resulting in a total of 24 articles for inclusion in this review. To assess inter-rater agreement, an independent rater reviewed these 24 articles according to the inclusion criteria. This resulted in 100% agreement for the initial three search methods. However, one discrepancy was identified in the author search. Upon review, this study [6] was excluded because the participant did not have a formal ASD diagnosis. Therefore, a total of 23 articles met the inclusion criteria.
Results
A total of 29 interventions/experiments were reported in the 23 included studies. Table I sum- marizes the purpose, participants, type of SGD, outcomes and design and certainty of evidence for each of the 23 included studies.
Participants
A total of 51 participants with ASD were included in the studies. When a study included participants with and without an ASD diagnosis, only data from the ASD participants were coded. Of these 51 participants, 90.2% (n ¼ 46) were boys and 9.8% (n ¼ 5) were girls, a ratio of nine boys to every girl. The majority of participants were reported as having autism (n ¼ 34, 66.7%), five as having ASD (9.8%) and 12 (23.5%) with pervasive developmental disorder–not otherwise specified (PDD-NOS). Of those with autism or ASD, diagnosis ranged from mild-to-severe and included Autistic disorder. Thirty-seven per cent of participants (n ¼ 19) also had a dual diagnosis of ASD and some level of intellectual disability or other developmental delay [10, 36–43]. In one study [24] the sole participant had a diagnosis of Down syndrome and Autistic disorder.
Ages ranged from 3–16 years (mean ¼ 7.7). In one study [44] age was not specifically identified, instead it was stated that participants were pre-school aged.
T ab
le I.
S
tu d
ie s
o n
t h
e ef
fe ct
s o f
sp ee
ch -g
en er
at in
g d
ev ic
es (
S G
D s)
o n
t h
e co
m m
u n
ic at
io n
o f
ch il d
re n
w it
h a
u ti
sm s
p ec
tr u
m d
is o rd
er .
D es
ig n
a n
d c
er ta
in ty
o f
S tu
d y
P u
rp o se
P
ar ti
ci p
an ts
S
G D
( sp
ee ch
t yp
e)
O u
tc o m
es
ev id
en ce
B ec
k e
t al
. [4
8 ]
B ra
d y
[5 2 ]
D u
ra n
d [
1 0 ]
F ra
n co
e t
al . [4
7 ]
M cM
il la
n [
3 6 ]
O li ve
e t
al .
[5 3 ]
O li ve
e t
al .
[4 6 ]
S ch
ep is
e t
al .
[2 5 ]
T o c
o m
p ar
e th
e ef
fe ct
s o f
ac q
u is
it io
n o
f P
ic tu
re
E x ch
an g e
C o m
m u
n ic
at io
n S
ys te
m (
P E
C S
)- an
d S
G D
-b as
ed r
eq u
es ti
n g f
o r
d es
ir ed
i te
m s.
A
ss es
sm en
t o f
ef fe
ct s
o n
v er
b al
iz at
io n
s
T o t
ea ch
S G
D u
se i
n j
o in
t ac
ti vi
ty r
o u
ti n
es t
o
re q
u es
t it
em s
an d
a ss
es s
ef fe
ct s
o n
co
m p
re h
en si
o n
T o a
ss es
s th
e ef
fe ct
s o f
fu n
ct io
n al
c o m
m u
n ic
a- ti
o n
t ra
in in
g (
F C
T )
u si
n g a
ss is
ti ve
c o m
m u
- n
ic at
io n
d ev
ic es
( S
G D
) o n
r eq
u es
ti n
g o
f o b
je ct
s an
d a
ct iv
it ie
s th
at w
er e
p re
su m
ed t
o
m ai
n ta
in t
h ei
r b
eh av
io u
r T
o e
x te
n d
F C
T a
n d
S G
D r
es ea
rc h
b y
ex am
in -
in g t
h e
ef fe
ct s
o f
an S
G D
p ro
g ra
m m
ed w
it h
m
u lt
ip le
m es
sa g es
o n
c h
al le
n g in
g b
eh av
io u
r m
ai n
ta in
ed b
y m
u lt
ip le
f u
n ct
io n
s
T o e
x am
in e
th e
ef fe
ct s
o f
m u
lt ip
h as
e te
ac h
er
p ro
fe ss
io n
al d
ev el
o p
m en
t an
d t
h e
u se
o f
ti m
e- d
el ay
m il ie
u t
ea ch
in g o
n t
h e
fr eq
u en
cy
o f
S G
D u
se f
o r
st u
d en
ts
T o e
va lu
at e
th e
ef fe
ct s
o f
en h
an ce
d m
il ie
u
te ac
h in
g c
o m
b in
ed w
it h
a S
G D
o n
t h
e re
q u
es ti
n g s
k il ls
o f
st u
d en
ts
T o e
x am
in e
ch an
g es
o n
s ta
n d
ar d
iz ed
m ea
su re
s o f
co m
m u
n ic
at io
n a
s a
re su
lt o
f F
C T
. S
p ec
if ic
al ly
t o u
se a
S G
D t
o t
ea ch
r ep
la ce
- m
en t
re q
u es
t fo
r at
te n
ti o n
t o r
ed u
ce c
h al
- le
n g in
g b
eh av
io u
r
T o e
x am
in e
th e
ef fe
ct s
o f
S G
D u
se t
au g h
t b
y a
n at
u ra
li st
ic t
ea ch
in g p
ro ce
d u
re o
n r
eq u
es ti
n g ,
an sw
er in
g y
es /n
o q
u es
ti o n
s an
d s
o ci
al
co m
m en
ti n
g
3 b
o ys
, 2 w
it h
au ti
sm a
n d
1 w
it h
P
D D
-N O
S (p
re -s
ch o o l
ag ed
)
1 g
ir l, w
it h
a u
ti sm
(5
y ea
rs )
2 b
o ys
, w
it h
a u
ti sm
an
d s
ev er
e m
en ta
l re
ta rd
at io
n .
(9 .5
an
d 1
1 .5
y ea
rs )
1 b
o y,
w it
h a
u ti
sm ye
ar s)
(7 .6
4 b
o ys
, w
it h
m o d
er -
at e
to s
ev er
e in
te ll ec
tu al
d is
- ab
il it
ie s
an d
A S
D
(8 – 1 2 y
ea rs
)
3 b
o ys
, w
it h
a u
ti sm
(4 5 – 6 6 m
o n
th s)
1 g
ir l, w
it h
a u
ti sm
sp ec
tr u
m d
is o r-
d er
( A
S D
) (4
y ea
rs )
3 b
o ys
a n
d 1
g ir
l,
w it
h a
u ti
sm (3
– 5 y
ea rs
)
G o T
al k ;
d ig
it iz
ed
S p
ea k E
as y;
p re
-r ec
o rd
ed d
ig it
iz ed
m es
sa g e
In tr
o ta
lk er
( P
re n
tk e
R o m
ic h
); d
ig it
iz ed
G o T
al k ; sp
ee ch
t yp
e n
o t
re co
rd ed
N o t
sp ec
if ie
d
C h
ea p
T al
k 4
I n
li n
e D
ir ec
t; d
ig it
iz ed
F o u
r B
u tt
o n
T o u
ch
T al
k D
ir ec
t; d
ig i-
ti ze
d (
p ar
ti ci
- p
an t’
s o w
n v
o ic
e)
C h
ea p
T al
k ;
d ig
i- ti
ze d
. B
la ck
H
aw k (
o n
ly p
ri n
te d
w o rd
s,
g ra
p h
ic r
ep re
se n
- ta
ti o n
); s
p ee
ch
ty p
e n
o t
re co
rd ed
O n
ly o
n e
ch il d
r ea
ch ed
c ri
te ri
o n
t o m
o ve
t o
p h
as e
II o
f S
G D
. P
re fe
re n
ce f
o r
o n
e m
o d
e o f
co m
m u
n ic
at io
n w
as n
o t
p re
d ic
ta b
le a
n d
in
fl u
en ce
o f
co m
m u
n ic
at io
n s
ys te
m o
n v
er -
b al
iz at
io n
s va
ri ed
P
ar ti
ci p
an t
le ar
n ed
t o r
eq u
es t
si x d
if fe
re n
t o b
je ct
s u
si n
g t
h e
S G
D a
s w
el l
as i
n cr
ea se
d
co m
p re
h en
si o n
s k il ls
f o r
th e
n am
es o
f th
e o b
je ct
s re
q u
es te
d
F o ll o w
in g F
C T
t ra
in in
g a
ll p
ar ti
ci p
an ts
e n
g ag
ed
in s
o m
e le
ve l
o f
u n
p ro
m p
te d
d ev
ic e
u se
w
it h
in t
h e
cl as
sr o o m
a n
d c
o m
m u
n it
y se
tt in
g
T h
e p
ar ti
ci p
an t
in cr
ea se
d u
se o
f S
G D
-b as
ed re
q u
es ti
n g (
to r
eq u
es t
b re
ak s
an d
a cc
es s
to
p re
fe rr
ed i
te m
s) b
as ed
o n
t h
e fu
n ct
io n
o f
th e
b eh
av io
u r
N o e
ff ec
t o n
s tu
d en
t S
G D
u se
d u
ri n
g p
h as
e 1 d
ev ic
e o p
er at
io n
. S
ig n
if ic
an t
in cr
ea se
s in
S G
D i n
it ia
ti o n
s d
u ri
n g p
h as
e 2 a
n d
r em
ai n
ed
h ig
h d
u ri
n g p
h as
e 3 .
T ra
in in
g h
ad a
m in
im al
ef
fe ct
o n
f re
q u
en cy
o f
d ev
ic e
re sp
o n
se s
p er
se
ss io
n b
et w
ee n
b as
el in
e an
d i
n te
rv en
ti o n
p h
as es
A ll p
ar ti
ci p
an ts
d em
o n
st ra
te d
a n
i n
cr ea
se i
n
S G
D u
se a
s w
el l
as a
n i
n cr
ea se
i n
t o ta
l sp
o n
ta n
eo u
s in
d ep
en d
en t
re q
u es
ts
Im p
le m
en ta
ti o n
o f
F C
T w
it h
S G
D r
es u
lt ed
i n
an
i m
m ed
ia te
d ec
re as
e in
c h
al le
n g in
g b
eh a-
vi o u
r an
d w
as r
ep li ca
te d
a cr
o ss
a ct
iv it
ie s.
In
te rv
en ti
o n
a ls
o r
es u
lt ed
i n
a n
i n
cr ea
se o
f at
te n
ti o n
r eq
u es
ti n
g .
A n
i n
cr ea
se i
n c
o rr
ec t
p ro
n o u
n u
se w
as a
ls o o
b se
rv ed
, as
w el
l as
a
p o si
ti ve
c h
an g e
in s
ta n
d ar
d iz
ed s
co re
s o f
la n
g u
ag e
an d
s o ci
al s
k il ls
A
ll c
h il d
re n
d is
p la
ye d
a n
i n
cr ea
se i
n c
o m
m u
n i-
ca ti
ve i
n te
ra ct
io n
s d
u ri
n g t
h e
S G
D a
n d
n at
- u
ra li st
ic t
ea ch
in g c
o n
d it
io n
s. S
G D
u se
d id
n
o t
re d
u ce
o th
er c
o m
m u
n ic
at iv
e b
eh av
io u
rs
an d
c o n
te x tu
al a
p p
ro p
ri at
en es
s o f
th e
S G
D
w as
s u
p p
o rt
ed .
C h
il d
re n
d id
u se
t h
e S
G D
f o r
a ra
n g e
o f
d if
fe re
n t
m es
sa g es
C o n
cl u
si ve
: A
lt er
n at
in g
tr ea
tm en
t d
es ig
n
In co
n cl
u si
ve :
T w
o c
as e
st u
d ie
s
C o n
cl u
si ve
: M
u lt
ip le
b as
e- li n
e ac
ro ss
p ar
ti ci
p an
ts d
es ig
n
C o n
cl u
si ve
: S
tu d
y 1 :
co m
- b
in ed
m u
lt ie
le m
en t
an d
re
ve rs
al d
es ig
n ;
S tu
d y
2 :
m u
lt ip
le b
as el
in e
ac ro
ss
tw o s
et ti
n g s
C o n
cl u
si ve
: M
u lt
ip le
b as
e- li n
e si
n g le
-c as
e ex
p er
i- m
en ta
l d
es ig
n a
cr o ss
st
u d
en t
an d
t ea
ch er
p
ar ti
ci p
an ts
C o n
cl u
si ve
: M
u lt
ip le
p ro
b e
ac ro
ss p
ar ti
ci p
an ts
d es
ig n
C o n
cl u
si ve
: M
u lt
ip le
p ro
b e
d es
ig n
a cr
o ss
f o u
r ac
ti vi
ti es
C o n
cl u
si ve
: M
u lt
ip le
p ro
b e
d es
ig n
a cr
o ss
t im
e an
d
ro u
ti n
es
Communication interventions 297
(c o n ti n u ed
)
T ab
le I.
C
o n
ti n
u ed
.
D es
ig n
a n
d c
er ta
in ty
o f
S tu
d y
P u
rp o se
P
ar ti
ci p
an ts
S
G D
( sp
ee ch
t yp
e)
O u
tc o m
es
ev id
en ce
S ch
lo ss
er
et
al .
T o e
x am
in e
th e
ef fe
ct s
o f
sy n
th et
ic s
p ee
ch
1 b
o y,
w it
h a
u ti
sm
L ig
h tW
R IT
E R
S L
D
u ri
n g b
as el
in e
p er
fo rm
an ce
w as
a t
0 %
, d
u ri
n g
C o n
cl u
si ve
: A
d ap
te d
a lt
er -
[3 7 ]
o u
tp u
t an
d o
rt h
o g ra
p h
ic f
ee d
b ac
k o
n s
p el
li n
g
(1 0 y
ea rs
) 3 5 ;
te x t-
to -
tr ai
n in
g t
h e
p er
ce n
ta g e
o f
w o rd
s sp
el le
d
n at
in g t
re at
m en
ts d
es ig
n
sp ee
ch s
yn th
et ic
co
rr ec
tl y
ro se
t o c
ri te
ri o n
a n
d d
u ri
n g m
ai n
- sp
ee ch
o u
tp u
t te
n an
ce p
er ce
n ta
g e
o f
w o rd
s sp
el le
d c
o rr
ec tl
y (D
E C
ta lk
), w
it h
re
m ai
n ed
h ig
h a
cr o ss
c o n
d it
io n
s. T
h e
sa m
e a
Q W
E R
T Y
o cc
u rr
ed f o r
co rr
ec t
le tt
er s
eq u
en ce
s u
n d
er a
ll
k ey
b o ar
d
th re
e co
n d
it io
n s.
S p
ee ch
o u
tp u
t al
o n
e an
d i
n
co m
b in
at io
n w
it h
o rt
h o g ra
p h
ic f
ee d
b ac
k
re su
lt ed
i n
m o re
e ff
ic ie
n t
sp el
li n
g t
h an
o rt
h o g ra
p h
ic f
ee d
b ac
k a
lo n
e S
ch lo
ss er
an
d
T o s
ys te
m at
ic al
ly r
ep li ca
te S
ch lo
ss er
e t
al .’
s [3
7 ]
4 b
o ys
, w
it h
m il d
–
L ig
h tW
R IT
E R
-S -
P ar
ti ci
p an
ts r
ea ch
ed c
ri te
ri o n
( co
rr ec
t sp
el li n
g )
C o n
cl u
si ve
: A
d ap
te d
a lt
er -
B li sc
h ak
[ 5 0 ]
st u
d y
in o
rd er
t o d
et er
m in
e th
e ef
fe ct
s o f
m o d
er at
e au
ti sm
L
3 5 ;
sy n
th et
ic
ac ro
ss a
ll t
h re
e fe
ed b
ac k c
o n
d it
io n
s.
n at
in g t
re at
m en
ts d
es ig
n
sy n
th et
ic s
p ee
ch a
n d
p ri
n t
fe ed
b ac
k o
n
(8 – 1 2 y
ea rs
) sp
ee ch
E
ff ic
ie n
cy d
at a
va ri
ed f
ro m
t h
e p
re li m
in ar
y (w
it h
t h
re e
in st
ru ct
io n
al sp
el li n
g a
cq u
is it
io n
a n
d g
en er
al iz
at io
n
(D E
C ta
lk ),
w it
h
st u
d y
w it
h s
eq u
en ce
o f
ac q
u is
it io
n f
o r
th re
e se
ts u
si n
g t
h re
e d
if fe
r- a
Q W
E R
T Y
ch
il d
re n
b ei
n g :
P R
IN T
, S
P E
E C
H -P
R IN
T
en t,
b u
t eq
u iv
al en
t ‘c
al cu
la to
r’ t
yp e
an d
S P
E E
C H
. F
o r
th e
fo u
rt h
c h
il d
t h
e fo
u r-
w o rd
s et
s)
k ey
b o ar
d
se q
u en
ce w
as S
P E
E C
H -P
R IN
T ,
S P
E E
C H
an
d P
R IN
T
S ch
lo ss
er
et
al .
T o c
o m
p ar
e th
e ef
fe ct
iv en
es s
an d
e ff
ic ie
n cy
o f
1 g
ir l
an d
4 b
o ys
, T
h e
V an
ta g e;
T
h e
re su
lt s
in d
ic at
ed f
re q
u en
t re
q u
es ti
n g u
n d
er
C o n
cl u
si ve
: A
d ap
te d
a lt
er -
[3 8 ]
re q
u es
ti n
g w
h en
p ro
vi d
ed w
it h
s p
ee ch
o u
tp u
t w
it h
a u
ti sm
sy
n th
et ic
b
o th
c o n
d it
io n
s. T
w o p
ar ti
ci p
an ts
r eq
u es
te d
n
at in
g t
re at
m en
ts
d u
ri n
g i
n st
ru ct
io n
( S
P E
E C
H c
o n
d it
io n
) o r
(8 – 1 0 y
ea rs
) (D
E C
T al
k )
m o re
e ff
ec ti
ve ly
u n
d er
t h
e S
P E
E C
H c
o n
d i-
d es
ig n
, re
p li ca
te d
a cr
o ss
n
o s
p ee
ch o
u tp
u t
(N O
-S P
E E
C H
c o n
d it
io n
);
ti o n
a n
d o
n e
p ar
ti ci
p an
t re
q u
es te
d m
o re
fi
ve p
ar ti
ci p
an ts
as w
el l
as t
o m
o n
it o r
ch an
g es
i n
n at
u ra
l ef
fe ct
iv el
y u
n d
er t
h e
N O
-S P
E E
C H
c o n
d i-
sp ee
ch p
ro d
u ct
io n
ti
o n
, w
h il e
th er
e w
as n
o d
if fe
re n
ce f
o r
th e
re m
ai n
in g t
w o s
tu d
en ts
. A
s n
o n
e o f
th e
st u
d en
ts r
ea ch
ed c
ri te
ri o n
i t
w as
n o t
p o ss
ib le
to
a ss
es s
ef fi
ci en
cy o
f co
n d
it io
n s.
O n
ly o
n e
st u
d en
t sh
o w
ed a
n i
m p
ro ve
m en
t in
e li ci
te d
vo
ca li za
ti o n
s S
ig af
o o s
et
al .
T o d
et er
m in
e w
h et
h er
S G
D u
se c
o u
ld b
e ta
u g h
t 1 b
o y,
w it
h
B IG
m ac
k ;
d ig
it iz
ed
W it
h t
h e
o n
se t
o f
in te
rv en
ti o n
t h
e p
er ce
n ta
g e
o f
C o n
cl u
si ve
: [4
8 ]
d ir
ec tl
y as
a r
ep ai
r st
ra te
g y
fo r
co m
m u
n ic
a- P
D D
-N O
S
co rr
ec t
co m
m u
n ic
at io
n r
ep ai
rs i
n cr
ea se
d a
n d
M
u lt
ip le
-b as
el in
e d
es ig
n
ti o n
b re
ak d
o w
n s,
d is
ti n
ct f
ro m
t ea
ch in
g t
h e
(1 6 y
ea rs
) st
ab il iz
ed a
t 8 0 – 1 0 0 %
. A
s S
G D
u se
w as
ac
ro ss
p ar
ti ci
p an
ts in
it ia
ti o n
o f
a re
q u
es t
ac q
u ir
ed a
s a
re p
ai r
st ra
te g y,
d ev
ic e
u se
g en
er al
iz ed
t o i
n it
ia te
r eq
u es
ts w
h er
e th
er e
h ad
b ee
n n
o b
re ak
d o w
n i
n c
o m
m u
n ic
at io
n S
ig af
o o s
et
al .
F o ll o w
in g a
cq u
is it
io n
o f
S G
D t
o r
eq u
es t
it em
s T
w o b
o ys
, w
it h
B
IG m
ac k s
w it
ch ;
F o ll o w
in g r
ap id
a cq
u is
it io
n o
f S
G D
u se
s im
il ar
C
o n
cl u
si ve
: [4
5 ]
th e
ai m
o f
th e
st u
d y
w as
t o e
va lu
at e
ra te
s o f
se ve
re a
u ti
sm
d ig
it iz
ed
ra te
s o f
S G
D u
se w
er e
o b
se rv
ed d
u ri
n g t
h e
M u
lt ip
le -b
as el
in e
d es
ig n
re
q u
es ti
n g a
n d
v o ca
li za
ti o n
s co
m p
ar ed
a cr
o ss
(4
a n
d 1
3 y
ea rs
) tw
o c
o n
d it
io n
s o f
p o st
-a cq
u is
it io
n o
n /o
ff
ac ro
ss t
w o c
o n
d it
io n
s sp
ee ch
o u
tp u
t o n
a n
d s
p ee
ch o
u tp
u t
o ff
co
m p
ar is
o n
. T
h er
e w
er e
n o m
aj o r
o r
co n
si s-
co n
d it
io n
s te
n t
d if
fe re
n ce
s ac
ro ss
t h
e tw
o c
o n
d it
io n
s.
V o ca
li za
ti o n
s w
er e
st ea
d y
fr o m
b as
el in
e th
ro u
g h
b o th
c o n
d it
io n
s o f
p o st
-a cq
u is
it io
n
298 L. A. J. van der Meer & M. Rispoli
S ig
af o o s
et
al .
[3 9 ]
S ig
af o o s
et
al .
[2 4 ]
S ig
af o o s
et
al .
[5 1 ]
S ig
af o o s
et
al .
[4 0 ]
S o n
e t
al .
[2 6 ]
S o n
n en
m ei
er et
a l. [
5 4 ]
T h
u n
b er
g
et
al .
[4 1 ]
T o r
ed u
ce p
er se
rv er
at iv
e re
q u
es ti
n g u
si n
g a
S
G D
T o c
o m
p ar
e th
e ef
fe ct
s o f
ac q
u is
it io
n o
f S
G D
- an
d P
ic tu
re E
x ch
an g e
(P E
)- b
as ed
r eq
u es
ti n
g
re sp
o n
se ;
an d
t h
e ef
fe ct
s o n
s o ci
al i n
te ra
ct io
n
T o t
ea ch
a c
h il d
t o r
eq u
es t
sn ac
k s
u si
n g t
h re
e d
if fe
re n
t S
G D
s an
d e
va lu
at e
w h
ic h
S G
D h
e p
re fe
rr ed
t o u
se .
P re
fe re
n ce
b et
w ee
n t
h e
p re
fe rr
ed S
G D
a n
d a
c o m
m u
n ic
at io
n b
o ar
d
w as
t h
en e
va lu
at ed
T o t
ea ch
S G
D u
se t
o r
eq u
es t
p re
fe rr
ed i
te m
s as
w
el l
as d
et er
m in
e w
h et
h er
t h
ey w
o u
ld l
o ca
te
th ei
r S
G D
w h
en i
t w
as n
o t
w it
h in
r ea
ch
T o c
o m
p ar
e ac
q u
is it
io n
o f
re q
u es
ti n
g b
eh av
io u
r an
d p
re fe
re n
ce f
o r
a S
G D
v s
a P
E s
ys te
m
T o u
se t
h e
B ey
o n
d A
cc es
s m
o d
el w
it h
a f
o u
r p
h as
e p
ro ce
ss t
o l
ea d
t o i
m p
ro ve
d t
ea m
w o rk
, st
u d
en t
en g ag
em en
t an
d A
A C
o u
tc o m
es
T o a
ss es
s th
e u
se o
f S
G D
s in
t h
re e
d if
fe re
n t
ac ti
vi ti
es (
m ea
lt im
e, s
to ry
r ea
d in
g a
n d
‘s
h ar
in g e
x p
er ie
n ce
s o f
th e
p re
-s ch
o o l
d ay
’)
o n
t h
e d
ev el
o p
m en
t o f
co m
m u
n ic
at iv
e b
eh av
io u
rs
1 b
o y,
w it
h a
u ti
sm
an d
s ev
er e
ra n
g e
o f
in te
ll ec
tu al
d is
ab il it
y (1
2 y
ea rs
) 1 b
o y,
w it
h D
o w
n sy
n d
ro m
e an
d
A u
ti st
ic d
is o rd
er (1
5 y
ea rs
) 1 b
o y,
w it
h a
u ti
sm (1
2 y
ea rs
)
2 b
o ys
, 1 w
it h
P D
D -N
O S
a n
d
se ve
re m
en ta
l re
ta rd
at io
n a
n d
1
w it
h a
u ti
sm (1
2 a
n d
1 6 y
ea rs
) 2 g
ir ls
a n
d 1
b o y.
T
h e
2 g
ir ls
h ad
au
ti sm
a n
d t
h e
b o y
h ad
P D
D (3
– 5 y
ea rs
)
1 b
o y,
w it
h a
u ti
sm (1
0 y
ea rs
)
4 b
o ys
, w
it h
a n
A S
D ,
in cl
u d
in g 2
w
it h
P D
D -N
O S
(4 – 7 y
ea rs
)
B IG
m ac
k s
w it
ch ;
d ig
it iz
ed
T ec
h /T
al k 6
X 8 ;
d ig
it iz
ed
B IG
m ac
k s
w it
ch ,
T ec
h /T
al k 6
X 8 ,
M in
i- m
es sa
g eM
- A
te (
W o rd
sþ );
a ll
d ig
it iz
ed
T ec
h /T
al k ;
d ig
it iz
ed
T ec
h /T
al k 6
X 8 ;
d ig
it iz
ed
G o T
al k ;
n o t
sp ec
i- fi
ed .
D yn
aM yt
e;
n o t
sp ec
if ie
d
T h
re e
p ar
ti ci
p an
ts u
se d
a p
o rt
ab le
to u
ch -s
cr ee
n co
m p
u te
r an
d
C li ck
er 3
. O
n e
u se
d a
T ec
h T
al k ;
al l
w it
h a
c o m
b i-
n at
io n
o f
sy n
- th
et ic
a n
d d
ig it
iz ed
v o ic
e o u
tp u
t
B y
th e
la st
r es
p o n
se i
n te
rr u
p ti
o n
c o n
d it
io n
p
er se
rv er
at iv
e re
q u
es ti
n g h
ad d
ro p
p ed
f o r
b o th
t h
e h
ig h
a n
d l
o w
p re
fe re
n ce
i te
m .
C o rr
ec t
re sp
o n
d in
g w
as m
ai n
ta in
ed a
t co
n -
si st
en tl
y h
ig h
r at
es t
h ro
u g h
o u
t th
e st
u d
y E
q u
al ly
r ap
id a
cq u
is it
io n
o f P
E -
an d
S G
D -b
as ed
re
q u
es ti
n g r
es p
o n
se .
O n
ly t
h e
d is
ta n
ci n
g
m an
ip u
la ti
o n
h ad
a p
o si
ti ve
e ff
ec t
o n
s o ci
al
in te
ra ct
io n
T h
e p
ar ti
ci p
an t
le ar
n t
to u
se t
h e
S G
D s
to
re q
u es
t sn
ac k s.
I n
t h
e fi
rs t
d em
o n
st ra
ti o n
h e
n ev
er f
ai le
d t
o m
ak e
a ch
o ic
e an
d c
o n
si st
en tl
y p
re fe
rr ed
o n
e o f
th e
S G
D s
(M in
i- m
es sa
g eM
at e)
. In
t h
e se
co n
d d
em o n
- st
ra ti
o n
h e
sh o w
ed a
p re
fe re
n ce
f o r
th e
S G
D
o ve
r th
e co
m m
u n
ic at
io n
b o ar
d
T h
e p
er ce
n ta
g e
o f
co rr
ec t
re sp
o n
se s
w h
en t
h e
S G
D w
as o
u t
o f
re ac
h i
n cr
ea se
d w
it h
t h
e o n
se t
o f
in te
rv en
ti o n
a n
d s
ta b
il iz
ed a
t a
h ig
h
le ve
l
A ll t
h re
e p
ar ti
ci p
an ts
d em
o n
st ra
te d
a n
i n
cr ea
se d
p
er ce
n ta
g e
o f
co rr
ec t
re q
u es
ts a
cr o ss
i n
te r-
ve n
ti o n
s es
si o n
s, w
it h
l it
tl e
d if
fe re
n ce
b
et w
ee n
t h
e S
G D
a n
d p
ic tu
re e
x ch
an g e
sy st
em .
O n
ly o
n e
o f
th e
th re
e ch
il d
re n
sh
o w
ed a
p re
fe re
n ce
f o r
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Communication interventions 299
300 L. A. J. van der Meer & M. Rispoli
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Communication interventions 301
In this case age was estimated and calculated as 3 years. Two other studies [22, 36] only provided the age range of their participants and not individual ages. In these cases the average of the studies’ sample was used to calculate the overall average. Sample sizes from the 23 articles ranged from one to five participants. Just under half (n ¼ 9, 39.1%) had one participant. Only one study [38] had five participants.
Settings
The most common setting for intervention was in participants’ pre-schools or schools (n ¼ 18, 69.2%). For the three studies [10, 44, 45] that were conducted in multiple settings the settings were counted separately (there were therefore 26 settings for the 23 studies). Six (23.1%) studies [22, 41–44, 46] were undertaken in the participant’s homes, one [10] intervention was undertaken in the com- munity and one in a hospital [45].
Mode of communication
A total of 14 different types of SGDs were used in the 29 individual interventions reported. Several used more than one type of SGD per study and more than one speech type (i.e. digitized and synthetic). In such cases each SGD and speech type was recorded separately. Of the various SGDs used, the Tech/Talk 6X8 had the highest frequency (n ¼ 6, 20.7%), followed by the BigMack (n ¼ 4, 13.8%) and both the GoTalk and touch screen computer with Clicker 3 each being used three times (10.3%). The CheapTalk 4 Inline Direct and LightWRITER SL35 were each used twice (6.9%). Finally the SpeakEasy, Introtalker, Four Button Touch Talk Direct, Black Hawk, The Vantage, Mini- messageMATE (Wordsþ), DynaMyte and Talara-32 were all used once (3.4%). One study [5] did not specify what sort of SGD was used. Sixty-two per cent (n ¼ 18) of studies used digitized voice-output, while 20.7% (n ¼ 6) of studies used synthesized voice-output and 17.3% (n ¼ 5) did not specify voice-output.
Sixty-one per cent (n ¼ 14) of the studies provided some rationale and justification for the type of SGD selected. Of these, six studies [10, 25, 36, 45, 47, 48] based SGD selection on the participant’s motor skills and resulting ability to depress the SGD keys. Five studies [25, 41–43, 49] based SGD selection on the participant’s current vocabulary and level of communication skills, while four studies [37, 38, 50, 51] chose SGDs with characteristics that related to the aims of the study. For example, Schlosser et al. [38] chose the Vantage because the device could be held constant within and across all planned replication studies while only manipulating
the type of voice output (synthetic, digitized or no-speech).
Communication skills taught to the participants
Targeted communication skills were classified into broad categories, including: (a) requesting preferred items (e.g. food and snacks), activities, actions and locations, (b) conversation and social commenting involving single words, short phrases or sentence starters, (c) answering questions (e.g. yes/no ques- tions), (d) spelling, (e) reducing perserverative requesting and irrelevant speech, (f) increasing natural speech and (g) other communicative beha- viours (e.g. gestures, engagement in conversation, turn-taking, communicative form, function and effectiveness). Studies were also classified in terms of certain skills surrounding SGD use, including (a) independent SGD use (initiations and responses), (b) SGD use as a communication repair strategy, (c) location of the SGD and (d) SGD preference. Many of the studies taught more than one of the skills listed above. In such cases the skills were counted separately. Over half (n ¼ 16, 69.5%) of the articles taught participants some form of requesting as the primary communication skill. This was followed by conversation and social commenting (n ¼ 6, 26%).
Intervention procedures
Sixty per cent (n ¼ 15) of the articles used some form of the following operant/behavioural instruc- tional procedures to teach the use of an SGD: (a) presenting an opportunity or discriminative stimulus, (b) prompting a communicative behaviour, (c) fading prompts and (d) providing reinforcement for correct communicative behaviour. Within this broad class of behavioural procedures some studies also identified more specific techniques as their core teaching mechanism, including (a) functional beha- viour analysis (FBA) and functional communication training (FCT) [10, 46, 47], (b) graduated guidance procedure [24, 45, 48], (c) least to most prompting [22, 40, 51], (d) most to least prompting [44], (e) error correction procedure [52], (f) constant time delay method [38], (g) response interruption tech- nique to reduce requesting [39], (h) spelling taught using a SGD and implementing a ‘copy-cover- compare’ method [37, 50], (i) modelling by an adult [41–43] and (j) modelling by a peer [49].
Several studies focused on staff training, employ- ing several techniques to teach SGD use. These studies moved away from typical behavioural tech- niques, instead focusing on (a) time-delay milieu teaching or enhanced milieu teaching [36, 53], (b) incidental or naturalistic teaching [25] and (c) The Beyond Access model [54].
302 L. A. J. van der Meer & M. Rispoli
Outcomes
Outcomes were classified and ranked into one of three outcome categories: (a) positive outcomes in which target communication skill(s) improved for all participants, (b) negative outcomes in which none of the participants improved in the target commu- nication skill(s) and, finally, (c) mixed outcomes in which improvement was evident for some, but not all participants in the study or in which some target skills improved and others did not. Eighty-seven per cent of studies (n ¼ 20) reported positive outcomes and 13% (n ¼ 3) reported mixed outcomes. Within these mixed outcomes only one of the participants did not learn to use the SGD [44]. None of the reviewed studies reported negative outcomes.
Follow-up and generalization
Seven (30.4%) of the studies [25, 36–38, 45, 47, 50] undertook some form of follow-up. Not all studies mentioned when follow-ups occurred. However, for those that did, follow-up occurred from 1 week after intervention [38, 50] to 3 months after intervention [47] and continued for 3 weeks [38, 50] through 1 year [25] post-intervention. All maintenance data was successful to some extent, although some results varied between participants.
Ten studies (43.5%) [10, 36, 40, 44, 46–50, 52] undertook some form of generalization. Several of the studies reporting generalization were anecdotal in nature where some form of natural generalization was found without any specific testing [10, 40, 46, 48, 52]. Generalization across settings occurred for five studies [10, 36, 44, 47, 49], across people for one study [40] and across tasks for five studies [36, 46, 48, 50, 52]. All generalization data were successful to some extent, although some results were variable between participants and not all studies collected generalization data for all partici- pants [44, 52].
Reliability and treatment integrity
Ninety-six per cent (n ¼ 22) of studies reported reliability of data collection with respect to the dependent variables, such as collecting inter- observer agreement (IOA). Eighty-six per cent (n ¼ 19) of these studies reported average rates of inter-observer agreement above the generally accepted standard of 80% reliability [55]. Only one study [36] did not collect any reliability data. Fewer studies (39%, n ¼ 9) reported treatment integrity data for the accurate implementation of intervention procedures [24, 37–39, 43, 46, 50, 52, 53]. All of these studies reported high treatment integrity scores of over 80% correct implementation.
Design and certainty of evidence
Twenty (87%) of the 23 studies used some variation of a single-case design [55] to evaluate the effects of the SGD intervention on communication. Certainty of evidence was based on whether or not the study included a recognized experimental design. Studies were classified as conclusive if they system- atically introduced and removed the intervention (e.g. ABAB) [39] or the independent variable was sequentially introduced in accordance with a concurrent baseline (e.g. multiple-baseline, multiple- probe or alternating treatments design) [10, 22, 24, 25, 36–38, 40, 44–51, 53]. Studies were classified as inconclusive if they used intervention only, A–B or case study (narrative) designs [41–43, 52, 54]. According to these criteria, 18 (78%) of the 23 studies were deemed conclusive, while five (22%) of the 23 studies were deemed inconclusive, as they either involved a pre-experimental A–B design [42, 43] or employed a case study design [41, 52, 54].
Discussion
The purpose of the current review was to provide an overview of the research surrounding communica- tion interventions involving the use of SGDs for children with ASD. The systematic search identified 29 interventions reported in 23 studies, with a total of 51 participants published between 1998–2009. It therefore appears that in recent years there has been a rapid increase in research related to SGDs as an AAC intervention for children with ASD. It is interesting to note that such extensive growth has occurred after several articles in a 2001 issue of Focus on Autism and Other Developmental Disabilities high- lighted the apparent need for more empirically-based applied research specific to AAC and ASD [6, 20, 27, 56, 57]. In terms of the quality of evidence, the majority of studies reviewed here implemented experimental designs and achieved clear intervention results, where positive outcomes and certainty of evidence were both high (87% and 78%, respec- tively). As a result, 78% of studies were classified as demonstrating conclusive evidence. However, because not all studies demonstrated positive out- comes as well as conclusive evidence in relation to experimental design, these encouraging findings should still be interpreted with caution.
This review identified several trends, including (a) a clear tendency for targeting requesting as the main communication skill taught, (b) that instruc- tional approach reflects the communication skill being taught, (c) the need to incorporate generaliza- tion and maintenance strategies into treatment procedures, (d) the development of preference studies to enable self-determination in AAC
Communication interventions 303
interventions and (e) the predominance of single-case designs and resulting individual out- comes. There appear to have been no large-scale randomized control trials evaluating SGDs for chil- dren with ASD. These trends have implications for practice and future intervention research.
In relation to the first trend, the prevalence of research studies targeting requesting skills reflects findings of other reviews where the greatest group of intervention studies focused on teaching simple requests using various modes of AAC to individuals with ASD [7, 18, 23]. This is not surprising consid- ering it has been recommended that interventions begin by teaching a simple requesting response if it does not develop naturally [57, 58]. However, requesting is predominantly the beginning and end of AAC interventions for individuals with ASD; it is often the only communicative skill taught [59, 60]. Future research should examine the transition from teaching early requesting skills to more advanced communication using SGDs. In order to do so expectations of the child’s propensity to learn more advanced language skills may need to be raised [60]. Overall this review suggests that to maximize effec- tiveness of SGD selection and intervention, clinicians should consider a multitude of factors including considering children’s preferences for different SGDs, decreasing learning demands, representation of language concepts, organization, navigation, selec- tion technique and output [26].
Over half the articles analysed within this review provided some rationale and justification for the type of SGD selected. SGD selection was often based on participants’ motor skills and their resulting ability to use the SGD, as well as their level of communication skills in relation to complexity of the SGD selected. This selection process has implica- tions for practitioners who are faced with selecting a specific SGD for students with ASD. By consid- ering the individual’s motor skills the practitioner can ensure the individual can easily activate and navigate the SGD. The consideration of an individ- ual’s current communication skills and future com- munication goals is critical in making it possible to move beyond targeting requesting skills to teach more complex communication. In this way one can ensure every individual is provided with a ‘viable, robust, flexible, and generative communication system that will support long-term language devel- opment’ ([60], p. 225).
In terms of the second trend, intervention procedures were classified into two main categories: behavioural approaches, such as discrete-trial train- ing, or naturalistic approaches, such as milieu teaching. Distinct patterns emerged from these studies with respect to the instructional procedures used and the communication skills taught. Studies
that used discrete-trial training most commonly taught requesting of preferred items, whereas studies that utilized a naturalistic instructional approach (e.g. peer and adult modelling) more frequently taught simple social initiations and conversational skills. This reflects a similar trend for children with other types of developmental disabilities [61]. It could be that operant instructional procedures are best suited for teaching initial requesting behaviours and when communication becomes more complex in nature a naturalistic approach is more effective. Future research is recommended to determine which instructional strategy is best suited for the level of communication skills being taught.
The third trend illustrates that, while a number of studies did collect some generalization (43.5%) and maintenance (30.4%) data, most studies were limited to teaching one communication skill within the school setting. Of the studies that did report generalization several were anecdotal in nature, where generalization was found without any formal testing, reflecting a ‘train and hope’ approach to generalization [29]. Future research should focus on programming SGDs with multiple messages that can be used across a range of settings (school, home and the community), as a purposeful strategy to assess if SGD use will generalize to other contexts. More follow-up data is also warranted to assess whether such skills will maintain over time.
The comparison of intervention approaches using SGDs vs other AAC strategies was analysed in several studies [22, 24, 44, 51] and presents another area with significant implications for practice and future research. These studies have demonstrated that children with ASD can show a preference for using different types of AAC communication. This is con- sistent with a fourth trend where enabling students to participate in the selection of their communication device is one means of promoting self-determination. Future research is recommended to determine whether individuals’ preference for a specific device results in more effective and efficient device operation and development of communication skills.
Some of this preference research suggests that several individuals may prefer to use SGDs over other AAC modes [51], although other research has identified that this does not seem to be true for all learners [22]. Similarly, studies by Schlosser et al. [37] and Schlosser and Blischak [50] examining which feedback mode (auditory or visual) on an SGD had the most effective outcome on spelling support this notion, where results varied depending on the individual participant. This relates to the fifth trend that interventions can result in a range of outcomes and highlights the importance of indivi- dualized assessment.
304 L. A. J. van der Meer & M. Rispoli
The current review demonstrates recent strength in empirically examining the effects of SGD inter- ventions for students with ASD. The majority of studies reported improvements in the child’s ability to use SGDs to communicate following intervention. An SGD has many advantages over other AAC modes of communication; in particular it is easily used by the student and understood by others making it a functional mode of communication [28]. These advantages together with the positive outcomes reported make SGD-based interventions a potentially effective option for teaching communi- cation skills to children with ASD.
Declaration of interest: The authors report no conflicts of interests. The authors alone are respon- sible for the content and writing of this paper.
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