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 MEER 1 & MANDY RISPOLI 2 1 Victoria University of Wellington, Wellington, New Zealand and 2 Texas 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 revisio ´n sintetiza los estudios sobre intervenciones de comunicacio ´n que utilizan dispositivos de generacio ´n del habla (SGD) para nin ˜os con autismo. Me ´todos: Posterior a una bu ´ squeda sistematizada de listas de referencias, revistas y bases de datos electro ´nicas se identificaron veintitre ´s estudios que cumplı ´an con los criterios de inclusio ´n. Los estudios fueron evaluados en te ´rminos de: (a) participantes, (b) escenario, (c) medio de comunicacio ´n, (d) habilidad(es) de comunicacio ´n ensen ˜adas a los participantes, (e) procedimiento de intervencio ´ n, (f) resultados, (g) seguimiento y generalizacio ´n, (h) integridad y confiabilidad del tratamiento y (i) disen ˜o y certeza de la evidencia. Resultados: Se proporciono ´ intervencio ´ n, con mayor intere ´s en las habilidades de peticio ´ n, a un total de 51 nin ˜ os con edades comprendidas entre los 3 y los 16 an ˜ os de edad. Las estrategias de intervencio ´n siguieron dos enfoques principalmente: te ´cnicas operantes/conductuales y el enfoque de ensen ˜ anza naturalista. Se reportaron resultados positivos en el 86% de los estudios y el 78% de los estudios se categorizaron como aportadores de pruebas concluyente. Conclusio ´n: Esta literatura de base sugiere que los SGD son una opcio ´ n viable de comunicacio ´ n para nin ˜ os con autismo. Sin embargo, mu ´ltiples a ´reas ameritan una mayor investigacio ´n. Palabras clave: autismo, ASD, dispositivos de generacio ´n del habla, dispositivo de ayuda de comunicacio ´n de produccio ´n de la voz, comunicacio ´n, intervencio ´n Introduction Individuals with Autism Spectrum Disorders (ASD) are characterized by having significant impairments in social interaction, communication development and the presence of restricted, repetitive and stereotyped behaviour patterns [1]. Up to half of children with autism do not develop speech or develop only limited speech and language abilities [2–6]. Instead these children may rely on pre-linguistic behaviours, including pointing, 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 ß 2010 Informa UK Ltd. DOI: 10.3109/17518421003671494 Dev Neurorehabil Downloaded from informahealthcare.com by University of Melbourne on 10/03/13 For personal use only.
Transcript
Developmental Neurorehabilitation, August 2010; 13(4): 294–306
SUBJECT REVIEW
Communication interventions involving speech-generating devicesfor children with autism: A review of the literature
LARAH A. J. VAN DER MEER1 & MANDY RISPOLI2
1Victoria University of Wellington, Wellington, New Zealand and 2Texas A & M University, College Station, TX, USA
(Received 1 February 2010; accepted 1 February 2010)
AbstractObjective: The current review synthesizes communication intervention studies that involved the use of speech-generatingdevices (SGD) for children with autism.Methods: Twenty-three studies were identified that met the inclusion criteria following systematic searches of electronicdatabases, journals and reference lists. Studies were evaluated in terms of: (a) participants, (b) setting, (c) mode ofcommunication, (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 conclusiveevidence.Conclusion: The literature base suggests that SGDs are viable communication options for children with autism. However,several areas warrant future research.
ResumenObjetivo: La actual revision sintetiza los estudios sobre intervenciones de comunicacion que utilizan dispositivos degeneracion del habla (SGD) para ninos con autismo.Metodos: Posterior a una busqueda sistematizada de listas de referencias, revistas y bases de datos electronicas seidentificaron veintitres estudios que cumplıan con los criterios de inclusion. Los estudios fueron evaluados en terminos de:(a) participantes, (b) escenario, (c) medio de comunicacion, (d) habilidad(es) de comunicacion ensenadas a losparticipantes, (e) procedimiento de intervencion, (f) resultados, (g) seguimiento y generalizacion, (h) integridad yconfiabilidad del tratamiento y (i) diseno y certeza de la evidencia.Resultados: Se proporciono intervencion, con mayor interes en las habilidades de peticion, a un total de 51 ninos con edadescomprendidas entre los 3 y los 16 anos de edad. Las estrategias de intervencion siguieron dos enfoques principalmente:tecnicas operantes/conductuales y el enfoque de ensenanza naturalista. Se reportaron resultados positivos en el 86% de losestudios y el 78% de los estudios se categorizaron como aportadores de pruebas concluyente.Conclusion: Esta literatura de base sugiere que los SGD son una opcion viable de comunicacion para ninos con autismo. Sinembargo, multiples areas ameritan una mayor investigacion.
Palabras clave: autismo, ASD, dispositivos de generacion del habla, dispositivo de ayuda de comunicacion de produccion de la voz,comunicacion, intervencion
Introduction
Individuals with Autism Spectrum Disorders (ASD)are characterized by having significant impairmentsin social interaction, communication developmentand the presence of restricted, repetitive and
stereotyped behaviour patterns [1]. Up to half ofchildren with autism do not develop speech ordevelop only limited speech and language abilities[2–6]. Instead these children may rely onpre-linguistic behaviours, including pointing,
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]
reaching, eye-gazing and other facial expressions [7,8]. Some children may also demonstrate challengingbehaviour, such as aggression, tantrums andself-injury in an attempt to communicate theirwants and needs [9, 10]. Such pre-linguisticbehaviours become frustrating for both the commu-nicator and the communication partner, as they areoften difficult to interpret.
Romski et al. [11] explained that it is unclearwhether children who lack speech at a young age willremain at this pre-linguistic level. Instead the child’scommunication status may change over time as afunction of maturity, intervention or both.One intervention that these children may benefitfrom is augmentative and alternative communication(AAC). AAC refers to a practice that aims tosupplement (i.e. augment) or replace (i.e. alternative)natural speech [12–15]. This is achieved either byunaided approaches, such as gestures or manualsigning; or by aided systems, involving graphics(traditional orthography, photographs or linedrawings). Aided systems use external equipmentwith a communicative function, such as PictureExchange (PE) [16, 17] or Speech-GeneratingDevices (SGDs), otherwise referred to as voiceoutput communication aids (VOCAs) [18].
In particular SGDs became prominent communi-cation options for many individuals with autism bythe 1980s and 1990s [19, 20]. A SGD is a portableelectronic devise that will produce either digitizedor synthesized speech output. The SGD displays avariety of graphic symbols to represent a messagethat is activated resulting in voice output when theindividual uses a finger, hand or some other meansto select the message [7].
To date SGD intervention research has typicallyinvolved teaching the individual to request access tohighly preferred items [18, 21]. For example, in aSGD intervention the individual might be taught totouch a picture or line drawing on the electronicspeech output device, which produces a pre-recorded message, such as ‘I want __’. In returnthe communication partner will deliver the requesteditem [22]. In addition to requesting, a number ofother communicative functions, such as comment-ing, greeting or answering questions would beimportant to teach to individuals with ASD [23].Most of these communication skills have been taughtwithin a positivist behaviour analytic approach usingoperant 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 varietyof SGDs can be selected and customized for inter-vention. SGDs can vary in design including perma-nence of the display (static or dynamic), number ofgraphic representations on the display and size of the
graphic symbols [26]. Consideration of the type ofvoice-output used (digitized vs synthesized) can alsobe important. For example, it has been hypothesizedthat the lack of variability and robotic nature ofsynthesized speech may need to be considered whenimplementing AAC with individuals with autism[27]. The voice-output feature of SGDs might alsomake this a more readily understood mode ofcommunication, thus promoting greater communityinclusion and participation [28].
An emerging corpus of intervention researchhas investigated the use of SGDs as well as AACin general with individuals with developmentaldisabilities or autism and there are several reviewsthat have focused on a number of issues relatedto this topic [7, 18, 19, 27, 29, 30]. Schlosser andLee [29], for example, provide support for the use ofAAC in general, but did not focus on individualmodalities of AAC, such as SGDs. Lancioni et al.[18] focused on the use of SGDs and PECs inteaching requesting behaviours to individuals withdevelopmental disabilities. They concluded thatoutcomes are encouraging, but methodologicalconcerns provide reason for results to be interpretedwith caution. Only Schlosser et al. [19] appearto specifically review research assessing the use ofSGDs for individuals with autism. Thus, in order toanswer empirical questions that remain in this field[31], a systematic review of SGD interventions withindividuals with autism is warranted. The aim of thecurrent report is to systematically review the litera-ture in this field and thereby evaluate whether thereis evidence to support that children with autism arecapable of learning to use an SGD to communicate.Specific objectives are to provide an up-to-datesynthesis of the literature in order to (a) assistclinicians in their practice of improving the commu-nication of children with autism and (b) identify gapsin the literature and areas in need of further research.Together these objectives may help to guide andinform evidence-based practice with respect to theuse of SGDs in communication interventions forchildren with autism.
Method
Search procedures
Systematic searches were conducted in six electronicdatabases: Cumulative Index of Nursing and AlliedHealth Literatures (CINAHL), Education ResourcesInformation Center (ERIC), Medline, Linguisticsand Language Behavior Abstracts (LLBA), Proquestand PsycINFO. Publication year was not restricted,but the search was limited to English-languagejournal articles. The search covered all dates coveredby these databases up to September 2009.
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For the CINAHL search, voice-output communi-cation aid (or speech-generating device) and autismwas entered into the All Text field. For the remainingdatabases, the free-text terms voice-output commu-nication aid (or VOCA or speech-generating device)and autism (or autism spectrum disorders) wereinserted into the Keywords field. Abstracts of therecords returned from these electronic searches werereviewed to identify studies for inclusion in the review(see Inclusion and Exclusion Criteria).
Three additional search strategies were used inorder to find other possibly relevant studies that mayhave been missed by the electronic search. First, thereference lists for the included studies were reviewedto identify additional articles for possible inclusion.Secondly, hand searches were completed for thejournals that had published the included studies.Finally, using an author search, the five databaseswere searched again for additional related work byauthors of the studies that met the inclusion criteria.From this combination of search procedures,25 articles were identified for possible inclusion inthe systematic review.
Inclusion and exclusion criteria
To be included in this review, the article had to bea research study that included children (518 yearsof age) with ASD and examined the effects of anintervention involving SGDs. Intervention wasdefined as implementing one or more therapeutic/teaching procedures for the purpose of trying toincrease or improve the child’s communication skillsor abilities through the use of a SGD. Examplescould include teaching a child to use an SGD to(a) make requests, (b) spell words or (c) repair acommunicative breakdown.
The research study had to obtain empiricaldata from which one could assess the success ofthe intervention. For example, a paper by Light et al.[32] initially identified for inclusion used casereports that did not provide objective data on SGDuse and was therefore not included in the currentreview. Studies that focused only on the descriptionof or assessment of communication skills were notincluded.
Data extraction
Each study identified was first evaluated to establishif it met the pre-determined inclusion criteria.All studies that met the inclusion criteria were thencoded 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) interventionprocedures (e.g. least to most prompting), (f)
outcomes of the intervention, (g) follow-up andgeneralization, if any, (h) reliability and treatmentintegrity and (i) experimental design and certainty ofevidence. The certainty of evidence was ratedas either conclusive or inconclusive [33, 34] inorder to provide an overview of the quality of theevidence across the studies reviewed [35].
Inter-rater agreement
The initial search of the six databases revealed15 articles that met the inclusion criteria for thisreview. Three articles were identified in the referencelist search; three articles were identified in thejournal search and finally three articles were identi-fied in the author search, resulting in a total of24 articles for inclusion in this review. To assessinter-rater agreement, an independent rater reviewedthese 24 articles according to the inclusion criteria.This resulted in 100% agreement for the initial threesearch methods. However, one discrepancy wasidentified in the author search. Upon review,this study [6] was excluded because the participantdid not have a formal ASD diagnosis. Therefore,a total of 23 articles met the inclusion criteria.
Results
A total of 29 interventions/experiments werereported in the 23 included studies. Table I sum-marizes the purpose, participants, type of SGD,outcomes and design and certainty of evidence foreach of the 23 included studies.
Participants
A total of 51 participants with ASD were includedin the studies. When a study included participantswith and without an ASD diagnosis, only datafrom the ASD participants were coded. Of these51 participants, 90.2% (n¼ 46) were boys and 9.8%(n¼ 5) were girls, a ratio of nine boys to every girl.The majority of participants were reported as havingautism (n¼ 34, 66.7%), five as having ASD (9.8%)and 12 (23.5%) with pervasive developmentaldisorder–not otherwise specified (PDD-NOS). Ofthose with autism or ASD, diagnosis ranged frommild-to-severe and included Autistic disorder.Thirty-seven per cent of participants (n¼19) alsohad a dual diagnosis of ASD and some level ofintellectual disability or other developmental delay[10, 36–43]. In one study [24] the sole participanthad a diagnosis of Down syndrome and Autisticdisorder.
Ages ranged from 3–16 years (mean¼ 7.7). In onestudy [44] age was not specifically identified, insteadit was stated that participants were pre-school aged.
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Tab
leI.
Stu
die
son
the
effe
cts
of
spee
ch-g
ener
atin
gd
evic
es(S
GD
s)on
the
com
mu
nic
atio
nof
child
ren
wit
hau
tism
spec
tru
md
isord
er.
Stu
dy
Pu
rpose
Par
tici
pan
tsS
GD
(sp
eech
typ
e)O
utc
om
esD
esig
nan
dce
rtai
nty
of
evid
ence
Bec
ket
al.
[48]
To
com
par
eth
eef
fect
sof
acq
uis
itio
nof
Pic
ture
Exc
han
geC
om
mu
nic
atio
nS
yste
m(P
EC
S)-
and
SG
D-b
ased
req
ues
tin
gfo
rd
esir
edit
ems.
Ass
essm
ent
of
effe
cts
on
verb
aliz
atio
ns
3b
oys
,2
wit
hau
tism
and
1w
ith
PD
D-N
OS
(pre
-sch
ool
aged
)
GoT
alk;
dig
itiz
edO
nly
on
ech
ild
reac
hed
crit
erio
nto
move
top
has
eII
of
SG
D.
Pre
fere
nce
for
on
em
od
eof
com
mu
nic
atio
nw
asn
ot
pre
dic
tab
lean
din
flu
ence
of
com
mu
nic
atio
nsy
stem
on
ver-
bal
izat
ion
sva
ried
Con
clu
sive
:A
lter
nat
ing
trea
tmen
td
esig
n
Bra
dy
[52]
To
teac
hS
GD
use
injo
int
acti
vity
rou
tin
esto
req
ues
tit
ems
and
asse
ssef
fect
son
com
pre
hen
sion
1gi
rl,
wit
hau
tism
(5ye
ars)
Sp
eakE
asy;
pre
-rec
ord
edd
igit
ized
mes
sage
Par
tici
pan
tle
arn
edto
req
ues
tsi
xd
iffe
ren
tob
ject
su
sin
gth
eS
GD
asw
ell
asin
crea
sed
com
pre
hen
sion
skills
for
the
nam
esof
the
ob
ject
sre
qu
este
d
Inco
ncl
usi
ve:
Tw
oca
sest
ud
ies
Du
ran
d[1
0]
To
asse
ssth
eef
fect
sof
fun
ctio
nal
com
mu
nic
a-ti
on
trai
nin
g(F
CT
)u
sin
gas
sist
ive
com
mu
-n
icat
ion
dev
ices
(SG
D)
on
req
ues
tin
gof
ob
ject
san
dac
tivi
ties
that
wer
ep
resu
med
tom
ain
tain
thei
rb
ehav
iou
r
2b
oys
,w
ith
auti
sman
dse
vere
men
tal
reta
rdat
ion
.(9
.5an
d11.5
year
s)
Intr
ota
lker
(Pre
ntk
eR
om
ich
);d
igit
ized
Follow
ing
FC
Ttr
ain
ing
allp
arti
cip
ants
enga
ged
inso
me
leve
lof
un
pro
mp
ted
dev
ice
use
wit
hin
the
clas
sroom
and
com
mu
nit
yse
ttin
g
Con
clu
sive
:M
ult
iple
bas
e-lin
eac
ross
par
tici
pan
tsd
esig
n
Fra
nco
etal
.[47]
To
exte
nd
FC
Tan
dS
GD
rese
arch
by
exam
in-
ing
the
effe
cts
of
anS
GD
pro
gram
med
wit
hm
ult
iple
mes
sage
son
chal
len
gin
gb
ehav
iou
rm
ain
tain
edb
ym
ult
iple
fun
ctio
ns
1b
oy,
wit
hau
tism
(7.6
year
s)G
oT
alk;
spee
chty
pe
not
reco
rded
Th
ep
arti
cip
ant
incr
ease
du
seof
SG
D-b
ased
req
ues
tin
g(t
ore
qu
est
bre
aks
and
acce
ssto
pre
ferr
edit
ems)
bas
edon
the
fun
ctio
nof
the
beh
avio
ur
Con
clu
sive
:S
tud
y1:
com
-b
ined
mu
ltie
lem
ent
and
reve
rsal
des
ign
;S
tud
y2:
mu
ltip
leb
asel
ine
acro
sstw
ose
ttin
gsM
cMilla
n[3
6]
To
exam
ine
the
effe
cts
of
mu
ltip
has
ete
ach
erp
rofe
ssio
nal
dev
elop
men
tan
dth
eu
seof
tim
e-d
elay
milie
ute
ach
ing
on
the
freq
uen
cyof
SG
Du
sefo
rst
ud
ents
4b
oys
,w
ith
mod
er-
ate
tose
vere
inte
llec
tual
dis
-ab
ilit
ies
and
AS
D(8
–12
year
s)
Not
spec
ifie
dN
oef
fect
on
stu
den
tS
GD
use
du
rin
gp
has
e1
dev
ice
op
erat
ion
.S
ign
ific
ant
incr
ease
sin
SG
Din
itia
tion
sd
uri
ng
ph
ase
2an
dre
mai
ned
hig
hd
uri
ng
ph
ase
3.
Tra
inin
gh
ada
min
imal
effe
cton
freq
uen
cyof
dev
ice
resp
on
ses
per
sess
ion
bet
wee
nb
asel
ine
and
inte
rven
tion
ph
ases
Con
clu
sive
:M
ult
iple
bas
e-lin
esi
ngl
e-ca
seex
per
i-m
enta
ld
esig
nac
ross
stu
den
tan
dte
ach
erp
arti
cip
ants
Olive
etal
.[5
3]
To
eval
uat
eth
eef
fect
sof
enh
ance
dm
ilie
ute
ach
ing
com
bin
edw
ith
aS
GD
on
the
req
ues
tin
gsk
ills
of
stu
den
ts
3b
oys
,w
ith
auti
sm(4
5–6
6m
on
ths)
Ch
eap
Tal
k4
Inlin
eD
irec
t;d
igit
ized
All
par
tici
pan
tsd
emon
stra
ted
anin
crea
sein
SG
Du
seas
wel
las
anin
crea
sein
tota
lsp
on
tan
eou
sin
dep
end
ent
req
ues
ts
Con
clu
sive
:M
ult
iple
pro
be
acro
ssp
arti
cip
ants
des
ign
Olive
etal
.[4
6]
To
exam
ine
chan
ges
on
stan
dar
diz
edm
easu
res
of
com
mu
nic
atio
nas
are
sult
of
FC
T.
Sp
ecif
ical
lyto
use
aS
GD
tote
ach
rep
lace
-m
ent
req
ues
tfo
rat
ten
tion
tore
du
cech
al-
len
gin
gb
ehav
iou
r
1gi
rl,
wit
hau
tism
spec
tru
md
isor-
der
(AS
D)
(4ye
ars)
Fou
rB
utt
on
Tou
chT
alk
Dir
ect;
dig
i-ti
zed
(par
tici
-p
ant’
sow
nvo
ice)
Imp
lem
enta
tion
of
FC
Tw
ith
SG
Dre
sult
edin
anim
med
iate
dec
reas
ein
chal
len
gin
gb
eha-
viou
ran
dw
asre
plica
ted
acro
ssac
tivi
ties
.In
terv
enti
on
also
resu
lted
inan
incr
ease
of
atte
nti
on
req
ues
tin
g.A
nin
crea
sein
corr
ect
pro
nou
nu
sew
asal
soob
serv
ed,
asw
ell
asa
posi
tive
chan
gein
stan
dar
diz
edsc
ore
sof
lan
guag
ean
dso
cial
skills
Con
clu
sive
:M
ult
iple
pro
be
des
ign
acro
ssfo
ur
acti
viti
es
Sch
epis
etal
.[2
5]
To
exam
ine
the
effe
cts
of
SG
Du
seta
ugh
tb
ya
nat
ura
list
icte
ach
ing
pro
ced
ure
on
req
ues
tin
g,an
swer
ing
yes/
no
qu
esti
on
san
dso
cial
com
men
tin
g
3b
oys
and
1gi
rl,
wit
hau
tism
(3–5
year
s)
Ch
eap
Tal
k;d
igi-
tize
d.
Bla
ckH
awk
(on
lyp
rin
ted
word
s,gr
aph
icre
pre
sen
-ta
tion
);sp
eech
typ
en
ot
reco
rded
All
child
ren
dis
pla
yed
anin
crea
sein
com
mu
ni-
cati
vein
tera
ctio
ns
du
rin
gth
eS
GD
and
nat
-u
ralist
icte
ach
ing
con
dit
ion
s.S
GD
use
did
not
red
uce
oth
erco
mm
un
icat
ive
beh
avio
urs
and
con
text
ual
app
rop
riat
enes
sof
the
SG
Dw
assu
pp
ort
ed.
Ch
ild
ren
did
use
the
SG
Dfo
ra
ran
geof
dif
fere
nt
mes
sage
s
Con
clu
sive
:M
ult
iple
pro
be
des
ign
acro
ssti
me
and
rou
tin
es
(con
tinued
)
Communication interventions 297
Dev
Neu
rore
habi
l Dow
nloa
ded
from
info
rmah
ealth
care
.com
by
Uni
vers
ity o
f M
elbo
urne
on
10/0
3/13
For
pers
onal
use
onl
y.
Tab
leI.
Con
tin
ued
.
Stu
dy
Pu
rpose
Par
tici
pan
tsS
GD
(sp
eech
typ
e)O
utc
om
esD
esig
nan
dce
rtai
nty
of
evid
ence
Sch
loss
eret
al.
[37]
To
exam
ine
the
effe
cts
of
syn
thet
icsp
eech
ou
tpu
tan
dort
hogr
aph
icfe
edb
ack
on
spel
lin
g1
boy,
wit
hau
tism
(10
year
s)L
igh
tWR
ITE
RS
L35;
text
-to-
spee
chsy
nth
etic
spee
chou
tpu
t(D
EC
talk
),w
ith
aQ
WE
RT
Yke
yboar
d
Du
rin
gb
asel
ine
per
form
ance
was
at0%
,d
uri
ng
trai
nin
gth
ep
erce
nta
geof
word
ssp
elle
dco
rrec
tly
rose
tocr
iter
ion
and
du
rin
gm
ain
-te
nan
cep
erce
nta
geof
word
ssp
elle
dco
rrec
tly
rem
ain
edh
igh
acro
ssco
nd
itio
ns.
Th
esa
me
occ
urr
edfo
rco
rrec
tle
tter
seq
uen
ces
un
der
all
thre
eco
nd
itio
ns.
Sp
eech
ou
tpu
tal
on
ean
din
com
bin
atio
nw
ith
ort
hogr
aph
icfe
edb
ack
resu
lted
inm
ore
effi
cien
tsp
ellin
gth
anort
hogr
aph
icfe
edb
ack
alon
e
Con
clu
sive
:A
dap
ted
alte
r-n
atin
gtr
eatm
ents
des
ign
Sch
loss
eran
dB
lisc
hak
[50]
To
syst
emat
ical
lyre
plica
teS
chlo
sser
etal
.’s
[37]
stu
dy
inord
erto
det
erm
ine
the
effe
cts
of
syn
thet
icsp
eech
and
pri
nt
feed
bac
kon
spel
lin
gac
qu
isit
ion
and
gen
eral
izat
ion
4b
oys
,w
ith
mild
–m
od
erat
eau
tism
(8–1
2ye
ars)
Lig
htW
RIT
ER
-S-
L35;
syn
thet
icsp
eech
(DE
Cta
lk),
wit
ha
QW
ER
TY
‘cal
cula
tor’
typ
eke
yboar
d
Par
tici
pan
tsre
ach
edcr
iter
ion
(corr
ect
spel
lin
g)ac
ross
all
thre
efe
edb
ack
con
dit
ion
s.E
ffic
ien
cyd
ata
vari
edfr
om
the
pre
lim
inar
yst
ud
yw
ith
seq
uen
ceof
acq
uis
itio
nfo
rth
ree
child
ren
bei
ng:
PR
INT
,S
PE
EC
H-P
RIN
Tan
dS
PE
EC
H.
For
the
fou
rth
child
the
seq
uen
cew
asS
PE
EC
H-P
RIN
T,
SP
EE
CH
and
PR
INT
Con
clu
sive
:A
dap
ted
alte
r-n
atin
gtr
eatm
ents
des
ign
(wit
hth
ree
inst
ruct
ion
alse
tsu
sin
gth
ree
dif
fer-
ent,
bu
teq
uiv
alen
tfo
ur-
word
sets
)
Sch
loss
eret
al.
[38]
To
com
par
eth
eef
fect
iven
ess
and
effi
cien
cyof
req
ues
tin
gw
hen
pro
vid
edw
ith
spee
chou
tpu
td
uri
ng
inst
ruct
ion
(SP
EE
CH
con
dit
ion
)or
no
spee
chou
tpu
t(N
O-S
PE
EC
Hco
nd
itio
n);
asw
ell
asto
mon
itor
chan
ges
inn
atu
ral
spee
chp
rod
uct
ion
1gi
rlan
d4
boys
,w
ith
auti
sm(8
–10
year
s)
Th
eV
anta
ge;
syn
thet
ic(D
EC
Tal
k)
Th
ere
sult
sin
dic
ated
freq
uen
tre
qu
esti
ng
un
der
both
con
dit
ion
s.T
wo
par
tici
pan
tsre
qu
este
dm
ore
effe
ctiv
ely
un
der
the
SP
EE
CH
con
di-
tion
and
on
ep
arti
cip
ant
req
ues
ted
more
effe
ctiv
ely
un
der
the
NO
-SP
EE
CH
con
di-
tion
,w
hile
ther
ew
asn
od
iffe
ren
cefo
rth
ere
mai
nin
gtw
ost
ud
ents
.A
sn
on
eof
the
stu
den
tsre
ach
edcr
iter
ion
itw
asn
ot
poss
ible
toas
sess
effi
cien
cyof
con
dit
ion
s.O
nly
on
est
ud
ent
show
edan
imp
rove
men
tin
elic
ited
voca
liza
tion
s
Con
clu
sive
:A
dap
ted
alte
r-n
atin
gtr
eatm
ents
des
ign
,re
plica
ted
acro
ssfi
vep
arti
cip
ants
Sig
afoos
etal
.[4
8]
To
det
erm
ine
wh
eth
erS
GD
use
cou
ldb
eta
ugh
td
irec
tly
asa
rep
air
stra
tegy
for
com
mu
nic
a-ti
on
bre
akd
ow
ns,
dis
tin
ctfr
om
teac
hin
gth
ein
itia
tion
of
are
qu
est
1b
oy,
wit
hP
DD
-NO
S(1
6ye
ars)
BIG
mac
k;d
igit
ized
Wit
hth
eon
set
of
inte
rven
tion
the
per
cen
tage
of
corr
ect
com
mu
nic
atio
nre
pai
rsin
crea
sed
and
stab
iliz
edat
80–1
00%
.A
sS
GD
use
was
acq
uir
edas
are
pai
rst
rate
gy,
dev
ice
use
gen
eral
ized
toin
itia
tere
qu
ests
wh
ere
ther
eh
adb
een
no
bre
akd
ow
nin
com
mu
nic
atio
n
Con
clu
sive
:M
ult
iple
-bas
elin
ed
esig
nac
ross
par
tici
pan
ts
Sig
afoos
etal
.[4
5]
Follow
ing
acq
uis
itio
nof
SG
Dto
req
ues
tit
ems
the
aim
of
the
stu
dy
was
toev
alu
ate
rate
sof
req
ues
tin
gan
dvo
caliza
tion
sco
mp
ared
acro
sssp
eech
ou
tpu
ton
and
spee
chou
tpu
toff
con
dit
ion
s
Tw
ob
oys
,w
ith
seve
reau
tism
(4an
d13
year
s)
BIG
mac
ksw
itch
;d
igit
ized
Follow
ing
rap
idac
qu
isit
ion
of
SG
Du
sesi
milar
rate
sof
SG
Du
sew
ere
ob
serv
edd
uri
ng
the
two
con
dit
ion
sof
post
-acq
uis
itio
non
/off
com
par
ison
.T
her
ew
ere
no
maj
or
or
con
sis-
ten
td
iffe
ren
ces
acro
ssth
etw
oco
nd
itio
ns.
Voca
liza
tion
sw
ere
stea
dy
from
bas
elin
eth
rou
ghb
oth
con
dit
ion
sof
post
-acq
uis
itio
n
Con
clu
sive
:M
ult
iple
-bas
elin
ed
esig
nac
ross
two
con
dit
ion
s
298 L. A. J. van der Meer & M. Rispoli
Dev
Neu
rore
habi
l Dow
nloa
ded
from
info
rmah
ealth
care
.com
by
Uni
vers
ity o
f M
elbo
urne
on
10/0
3/13
For
pers
onal
use
onl
y.
Sig
afoos
etal
.[3
9]
To
red
uce
per
serv
erat
ive
req
ues
tin
gu
sin
ga
SG
D1
boy,
wit
hau
tism
and
seve
rera
nge
of
inte
llec
tual
dis
abilit
y(1
2ye
ars)
BIG
mac
ksw
itch
;d
igit
ized
By
the
last
resp
on
sein
terr
up
tion
con
dit
ion
per
serv
erat
ive
req
ues
tin
gh
add
rop
ped
for
both
the
hig
han
dlo
wp
refe
ren
ceit
em.
Corr
ect
resp
on
din
gw
asm
ain
tain
edat
con
-si
sten
tly
hig
hra
tes
thro
ugh
ou
tth
est
ud
y
Con
clu
sive
:A
BA
Bex
per
i-m
enta
ld
esig
n
Sig
afoos
etal
.[2
4]
To
com
par
eth
eef
fect
sof
acq
uis
itio
nof
SG
D-
and
Pic
ture
Exc
han
ge(P
E)-
bas
edre
qu
esti
ng
resp
on
se;
and
the
effe
cts
on
soci
alin
tera
ctio
n
1b
oy,
wit
hD
ow
nsy
nd
rom
ean
dA
uti
stic
dis
ord
er(1
5ye
ars)
Tec
h/T
alk
6X
8;
dig
itiz
edE
qu
ally
rap
idac
qu
isit
ion
ofP
E-
and
SG
D-b
ased
req
ues
tin
gre
spon
se.
On
lyth
ed
ista
nci
ng
man
ipu
lati
on
had
ap
osi
tive
effe
cton
soci
alin
tera
ctio
n
Con
clu
sive
:A
lter
nat
ing
trea
tmen
tsd
esig
n
Sig
afoos
etal
.[5
1]
To
teac
ha
child
tore
qu
est
snac
ksu
sin
gth
ree
dif
fere
nt
SG
Ds
and
eval
uat
ew
hic
hS
GD
he
pre
ferr
edto
use
.P
refe
ren
ceb
etw
een
the
pre
ferr
edS
GD
and
aco
mm
un
icat
ion
boar
dw
asth
enev
alu
ated
1b
oy,
wit
hau
tism
(12
year
s)B
IGm
ack
swit
ch,
Tec
h/T
alk
6X
8,
Min
i-m
essa
geM
-A
te(W
ord
sþ);
all
dig
itiz
ed
Th
ep
arti
cip
ant
lear
nt
tou
seth
eS
GD
sto
req
ues
tsn
acks
.In
the
firs
td
emon
stra
tion
he
nev
erfa
iled
tom
ake
ach
oic
ean
dco
nsi
sten
tly
pre
ferr
edon
eof
the
SG
Ds
(Min
i-m
essa
geM
ate)
.In
the
seco
nd
dem
on
-st
rati
on
he
show
eda
pre
fere
nce
for
the
SG
Dove
rth
eco
mm
un
icat
ion
boar
d
Con
clu
sive
:M
ult
iple
-bas
elin
ed
esig
n,
wit
hch
oic
eas
sess
men
tfo
llow
ing
acq
uis
itio
nin
stru
ctio
n
Sig
afoos
etal
.[4
0]
To
teac
hS
GD
use
tore
qu
est
pre
ferr
edit
ems
asw
ell
asd
eter
min
ew
het
her
they
wou
ldlo
cate
thei
rS
GD
wh
enit
was
not
wit
hin
reac
h
2b
oys
,1
wit
hP
DD
-NO
San
dse
vere
men
tal
reta
rdat
ion
and
1w
ith
auti
sm(1
2an
d16
year
s)
Tec
h/T
alk;
dig
itiz
edT
he
per
cen
tage
of
corr
ect
resp
on
ses
wh
enth
eS
GD
was
ou
tof
reac
hin
crea
sed
wit
hth
eon
set
of
inte
rven
tion
and
stab
iliz
edat
ah
igh
leve
l
Con
clu
sive
:D
elay
edm
ult
iple
-bas
elin
eac
ross
par
tici
pan
tsd
esig
n
Son
etal
.[2
6]
To
com
par
eac
qu
isit
ion
of
req
ues
tin
gb
ehav
iou
ran
dp
refe
ren
cefo
ra
SG
Dvs
aP
Esy
stem
2gi
rls
and
1b
oy.
Th
e2
girl
sh
adau
tism
and
the
boy
had
PD
D(3
–5ye
ars)
Tec
h/T
alk
6X
8;
dig
itiz
edA
llth
ree
par
tici
pan
tsd
emon
stra
ted
anin
crea
sed
per
cen
tage
of
corr
ect
req
ues
tsac
ross
inte
r-ve
nti
on
sess
ion
s,w
ith
litt
led
iffe
ren
ceb
etw
een
the
SG
Dan
dp
ictu
reex
chan
gesy
stem
.O
nly
on
eof
the
thre
ech
ild
ren
show
eda
pre
fere
nce
for
the
SG
D
Con
clu
sive
:A
lter
nat
ing
trea
tmen
tsd
esig
n
Son
nen
mei
eret
al.
[54]
To
use
the
Bey
on
dA
cces
sm
od
elw
ith
afo
ur
ph
ase
pro
cess
tole
adto
imp
rove
dte
amw
ork
,st
ud
ent
enga
gem
ent
and
AA
Cou
tcom
es
1b
oy,
wit
hau
tism
(10
year
s)G
oT
alk;
not
spec
i-fi
ed.
Dyn
aMyt
e;n
ot
spec
ifie
d
Th
ep
arti
cip
ant
ach
ieve
dac
cura
tean
dco
nsi
s-te
nt
yes/
no
resp
on
seu
sin
gth
eG
oT
alk.
He
com
mu
nic
ated
sin
gle
word
san
dw
ord
com
-b
inat
ion
su
sin
gth
eD
ynaM
yte
tom
ake
req
ues
tsfo
rob
ject
s,ac
tion
san
dlo
cati
on
s,as
wel
las
com
men
ton
acti
viti
es.
He
cou
ldre
cogn
ize
word
sin
pri
nt
Inco
ncl
usi
ve:
Ob
serv
atio
nal
case
stu
dy
Th
un
ber
get
al.
[41]
To
asse
ssth
eu
seof
SG
Ds
inth
ree
dif
fere
nt
acti
viti
es(m
ealt
ime,
story
read
ing
and
‘sh
arin
gex
per
ien
ces
of
the
pre
-sch
ool
day
’)on
the
dev
elop
men
tof
com
mu
nic
ativ
eb
ehav
iou
rs
4b
oys
,w
ith
anA
SD
,in
clu
din
g2
wit
hP
DD
-NO
S(4
–7ye
ars)
Th
ree
par
tici
pan
tsu
sed
ap
ort
able
tou
ch-s
cree
nco
mp
ute
ran
dC
lick
er3.
On
eu
sed
aT
ech
Tal
k;al
lw
ith
aco
mb
i-n
atio
nof
syn
-th
etic
and
dig
itiz
edvo
ice
ou
tpu
t
Inal
lth
ree
acti
viti
esin
trod
uct
ion
of
the
SG
Dre
sult
edin
anin
crea
sein
com
mu
nic
ativ
eef
fect
iven
ess,
esp
ecia
lly
wh
enu
sefu
lfille
dth
em
ain
goal
san
dro
les
of
anac
tivi
ty.
Th
era
teof
effe
ctiv
enes
sin
crea
sed
most
du
rin
g‘s
har
ing
exp
erie
nce
sof
the
pre
-sch
ool
day
’an
dle
ast
du
rin
gm
ealt
ime
Inco
ncl
usi
ve:
Mix
edm
eth
-od
sca
sest
ud
yan
alys
isin
clu
din
ga
pre
-tes
t/p
ost
-tes
tm
ult
iple
sin
gle-
case
stu
dy
des
ign
(con
tinued
)
Communication interventions 299
Dev
Neu
rore
habi
l Dow
nloa
ded
from
info
rmah
ealth
care
.com
by
Uni
vers
ity o
f M
elbo
urne
on
10/0
3/13
For
pers
onal
use
onl
y.
Tab
leI.
Con
tin
ued
.
Stu
dy
Pu
rpose
Par
tici
pan
tsS
GD
(sp
eech
typ
e)O
utc
om
esD
esig
nan
dce
rtai
nty
of
evid
ence
Th
un
ber
get
al.
[42]
To
eval
uat
eth
eef
fect
sof
spee
chou
tpu
ton
con
vers
atio
nal
inte
ract
ion
usi
ng
anS
GD
4b
oys
wit
hin
the
auti
stic
spec
tru
m(5
–7.5
year
s)
Tec
hT
alk2
,C
lick
er3
on
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In this case age was estimated and calculated as3 years. Two other studies [22, 36] only provided theage range of their participants and not individualages. 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 tofive participants. Just under half (n¼ 9, 39.1%)had one participant. Only one study [38] had fiveparticipants.
Settings
The most common setting for intervention was inparticipants’ pre-schools or schools (n¼ 18, 69.2%).For the three studies [10, 44, 45] that wereconducted in multiple settings the settings werecounted separately (there were therefore 26 settingsfor 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 inthe 29 individual interventions reported. Severalused more than one type of SGD per study and morethan one speech type (i.e. digitized and synthetic).In such cases each SGD and speech type wasrecorded separately. Of the various SGDs used, theTech/Talk 6X8 had the highest frequency (n¼ 6,20.7%), followed by the BigMack (n¼ 4, 13.8%)and both the GoTalk and touch screen computerwith Clicker 3 each being used three times (10.3%).The CheapTalk 4 Inline Direct and LightWRITERSL35 were each used twice (6.9%). Finally theSpeakEasy, Introtalker, Four Button TouchTalk Direct, Black Hawk, The Vantage, Mini-messageMATE (Wordsþ), DynaMyte andTalara-32 were all used once (3.4%). One study[5] did not specify what sort of SGD was used.Sixty-two per cent (n¼ 18) of studies used digitizedvoice-output, while 20.7% (n¼ 6) of studies usedsynthesized voice-output and 17.3% (n¼ 5) did notspecify voice-output.
Sixty-one per cent (n¼ 14) of the studies providedsome rationale and justification for the type of SGDselected. Of these, six studies [10, 25, 36, 45, 47, 48]based SGD selection on the participant’s motorskills and resulting ability to depress the SGD keys.Five studies [25, 41–43, 49] based SGD selectionon the participant’s current vocabulary and levelof communication skills, while four studies [37, 38,50, 51] chose SGDs with characteristics that relatedto the aims of the study. For example, Schlosseret al. [38] chose the Vantage because the devicecould be held constant within and across allplanned replication studies while only manipulating
the type of voice output (synthetic, digitized orno-speech).
Communication skills taught to the participants
Targeted communication skills were classified intobroad categories, including: (a) requesting preferreditems (e.g. food and snacks), activities, actions andlocations, (b) conversation and social commentinginvolving single words, short phrases or sentencestarters, (c) answering questions (e.g. yes/no ques-tions), (d) spelling, (e) reducing perserverativerequesting and irrelevant speech, (f) increasingnatural speech and (g) other communicative beha-viours (e.g. gestures, engagement in conversation,turn-taking, communicative form, function andeffectiveness). Studies were also classified in termsof certain skills surrounding SGD use, including(a) independent SGD use (initiations andresponses), (b) SGD use as a communicationrepair strategy, (c) location of the SGD and(d) SGD preference. Many of the studies taughtmore than one of the skills listed above. In such casesthe skills were counted separately. Over half (n¼16,69.5%) of the articles taught participants someform of requesting as the primary communicationskill. This was followed by conversation and socialcommenting (n¼ 6, 26%).
Intervention procedures
Sixty per cent (n¼ 15) of the articles used someform of the following operant/behavioural instruc-tional procedures to teach the use of an SGD:(a) presenting an opportunity or discriminativestimulus, (b) prompting a communicative behaviour,(c) fading prompts and (d) providing reinforcementfor correct communicative behaviour. Within thisbroad class of behavioural procedures some studiesalso identified more specific techniques as their coreteaching mechanism, including (a) functional beha-viour analysis (FBA) and functional communicationtraining (FCT) [10, 46, 47], (b) graduated guidanceprocedure [24, 45, 48], (c) least to most prompting[22, 40, 51], (d) most to least prompting [44],(e) error correction procedure [52], (f) constant timedelay method [38], (g) response interruption tech-nique to reduce requesting [39], (h) spelling taughtusing a SGD and implementing a ‘copy-cover-compare’ method [37, 50], (i) modelling by anadult [41–43] and (j) modelling by a peer [49].
Several studies focused on staff training, employ-ing several techniques to teach SGD use. Thesestudies moved away from typical behavioural tech-niques, instead focusing on (a) time-delay milieuteaching or enhanced milieu teaching [36, 53],(b) incidental or naturalistic teaching [25] and(c) The Beyond Access model [54].
Communication interventions 301
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Outcomes
Outcomes were classified and ranked into one ofthree outcome categories: (a) positive outcomes inwhich target communication skill(s) improved forall participants, (b) negative outcomes in which noneof the participants improved in the target commu-nication skill(s) and, finally, (c) mixed outcomesin which improvement was evident for some, but notall participants in the study or in which some targetskills improved and others did not. Eighty-seven percent of studies (n¼20) reported positive outcomesand 13% (n¼ 3) reported mixed outcomes. Withinthese mixed outcomes only one of the participantsdid not learn to use the SGD [44]. None of thereviewed 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 studiesmentioned when follow-ups occurred. However, forthose that did, follow-up occurred from 1 week afterintervention [38, 50] to 3 months after intervention[47] and continued for 3 weeks [38, 50] through 1year [25] post-intervention. All maintenance datawas successful to some extent, although some resultsvaried between participants.
Ten studies (43.5%) [10, 36, 40, 44, 46–50, 52]undertook some form of generalization. Several ofthe studies reporting generalization were anecdotalin nature where some form of natural generalizationwas found without any specific testing [10, 40, 46,48, 52]. Generalization across settings occurredfor five studies [10, 36, 44, 47, 49], across peoplefor one study [40] and across tasks for five studies[36, 46, 48, 50, 52]. All generalization data weresuccessful to some extent, although some resultswere variable between participants and not allstudies collected generalization data for all partici-pants [44, 52].
Reliability and treatment integrity
Ninety-six per cent (n¼ 22) of studies reportedreliability of data collection with respect to thedependent variables, such as collecting inter-observer agreement (IOA). Eighty-six per cent(n¼ 19) of these studies reported average ratesof inter-observer agreement above the generallyaccepted standard of 80% reliability [55]. Only onestudy [36] did not collect any reliability data. Fewerstudies (39%, n¼ 9) reported treatment integritydata for the accurate implementation of interventionprocedures [24, 37–39, 43, 46, 50, 52, 53]. All ofthese studies reported high treatment integrity scoresof over 80% correct implementation.
Design and certainty of evidence
Twenty (87%) of the 23 studies used some variationof a single-case design [55] to evaluate the effectsof the SGD intervention on communication.Certainty of evidence was based on whether or notthe 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 variablewas sequentially introduced in accordance with aconcurrent baseline (e.g. multiple-baseline, multiple-probe or alternating treatments design) [10, 22, 24,25, 36–38, 40, 44–51, 53]. Studies were classified asinconclusive if they used intervention only, A–B orcase study (narrative) designs [41–43, 52, 54].According to these criteria, 18 (78%) of the 23studies were deemed conclusive, while five (22%) ofthe 23 studies were deemed inconclusive, as theyeither 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 anoverview of the research surrounding communica-tion interventions involving the use of SGDs forchildren with ASD. The systematic search identified29 interventions reported in 23 studies, with a totalof 51 participants published between 1998–2009.It therefore appears that in recent years there hasbeen a rapid increase in research related to SGDsas an AAC intervention for children with ASD. It isinteresting to note that such extensive growth hasoccurred after several articles in a 2001 issue of Focus
on Autism and Other Developmental Disabilities high-lighted the apparent need for more empirically-basedapplied research specific to AAC and ASD [6, 20,27, 56, 57]. In terms of the quality of evidence, themajority of studies reviewed here implementedexperimental designs and achieved clear interventionresults, where positive outcomes and certainty ofevidence were both high (87% and 78%, respec-tively). As a result, 78% of studies were classified asdemonstrating conclusive evidence. However,because not all studies demonstrated positive out-comes as well as conclusive evidence in relation toexperimental design, these encouraging findingsshould still be interpreted with caution.
This review identified several trends, including(a) a clear tendency for targeting requesting as themain communication skill taught, (b) that instruc-tional approach reflects the communication skillbeing taught, (c) the need to incorporate generaliza-tion and maintenance strategies into treatmentprocedures, (d) the development of preferencestudies to enable self-determination in AAC
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interventions and (e) the predominance ofsingle-case designs and resulting individual out-comes. There appear to have been no large-scalerandomized control trials evaluating SGDs for chil-dren with ASD. These trends have implications forpractice and future intervention research.
In relation to the first trend, the prevalence ofresearch studies targeting requesting skills reflectsfindings of other reviews where the greatest group ofintervention studies focused on teaching simplerequests using various modes of AAC to individualswith ASD [7, 18, 23]. This is not surprising consid-ering it has been recommended that interventionsbegin by teaching a simple requesting response if itdoes not develop naturally [57, 58]. However,requesting is predominantly the beginning and endof AAC interventions for individuals with ASD; it isoften the only communicative skill taught [59, 60].Future research should examine the transition fromteaching early requesting skills to more advancedcommunication using SGDs. In order to do soexpectations of the child’s propensity to learn moreadvanced language skills may need to be raised [60].Overall this review suggests that to maximize effec-tiveness of SGD selection and intervention, cliniciansshould consider a multitude of factors includingconsidering children’s preferences for differentSGDs, decreasing learning demands, representationof language concepts, organization, navigation, selec-tion technique and output [26].
Over half the articles analysed within this reviewprovided some rationale and justification for thetype of SGD selected. SGD selection was oftenbased on participants’ motor skills and their resultingability to use the SGD, as well as their level ofcommunication skills in relation to complexity of theSGD selected. This selection process has implica-tions for practitioners who are faced with selectinga specific SGD for students with ASD. By consid-ering the individual’s motor skills the practitionercan ensure the individual can easily activate andnavigate the SGD. The consideration of an individ-ual’s current communication skills and future com-munication goals is critical in making it possibleto move beyond targeting requesting skills to teachmore complex communication. In this way one canensure every individual is provided with a ‘viable,robust, flexible, and generative communicationsystem that will support long-term language devel-opment’ ([60], p. 225).
In terms of the second trend, interventionprocedures were classified into two main categories:behavioural approaches, such as discrete-trial train-ing, or naturalistic approaches, such as milieuteaching. Distinct patterns emerged from thesestudies with respect to the instructional proceduresused and the communication skills taught. Studies
that used discrete-trial training most commonlytaught requesting of preferred items, whereas studiesthat utilized a naturalistic instructional approach(e.g. peer and adult modelling) more frequentlytaught simple social initiations and conversationalskills. This reflects a similar trend for childrenwith other types of developmental disabilities [61].It could be that operant instructional procedures arebest suited for teaching initial requesting behavioursand when communication becomes more complexin nature a naturalistic approach is more effective.Future research is recommended to determine whichinstructional strategy is best suited for the level ofcommunication skills being taught.
The third trend illustrates that, while a numberof studies did collect some generalization (43.5%)and maintenance (30.4%) data, most studies werelimited to teaching one communication skill withinthe school setting. Of the studies that did reportgeneralization several were anecdotal in nature,where generalization was found without any formaltesting, reflecting a ‘train and hope’ approach togeneralization [29]. Future research should focus onprogramming SGDs with multiple messages that canbe used across a range of settings (school, homeand the community), as a purposeful strategy toassess if SGD use will generalize to other contexts.More follow-up data is also warranted to assesswhether such skills will maintain over time.
The comparison of intervention approaches usingSGDs vs other AAC strategies was analysed in severalstudies [22, 24, 44, 51] and presents another areawith significant implications for practice and futureresearch. These studies have demonstrated thatchildren with ASD can show a preference for usingdifferent types of AAC communication. This is con-sistent with a fourth trend where enabling students toparticipate in the selection of their communicationdevice is one means of promoting self-determination.Future research is recommended to determinewhether individuals’ preference for a specific deviceresults in more effective and efficient device operationand development of communication skills.
Some of this preference research suggests thatseveral individuals may prefer to use SGDs overother AAC modes [51], although other research hasidentified that this does not seem to be true for alllearners [22]. Similarly, studies by Schlosser et al.[37] and Schlosser and Blischak [50] examiningwhich feedback mode (auditory or visual) on anSGD had the most effective outcome on spellingsupport this notion, where results varied dependingon the individual participant. This relates to the fifthtrend that interventions can result in a range ofoutcomes and highlights the importance of indivi-dualized assessment.
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The current review demonstrates recent strengthin empirically examining the effects of SGD inter-ventions for students with ASD. The majority ofstudies reported improvements in the child’s abilityto use SGDs to communicate following intervention.An SGD has many advantages over other AACmodes of communication; in particular it is easilyused by the student and understood by othersmaking it a functional mode of communication[28]. These advantages together with the positiveoutcomes reported make SGD-based interventions apotentially effective option for teaching communi-cation skills to children with ASD.
Declaration of interest: The authors report noconflicts of interests. The authors alone are respon-sible for the content and writing of this paper.
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