The role of augmentative and alternative communication for children with autism: current status and future trends

Figures & data

Figure 1 Flow chart of systematic search.

Table 1 Summaries of included reviews

Study	Aims (review period)	Effect size indicator	Key findings
Overall effectiveness and comparison across variables
Ganz et al^Citation19	Meta-analysis of ESCD for effects of AAC on communication, social skills, and CB, and differences across age and autism diagnostic categories (1980–2008)	IRD	•24 studies •Aided AAC: PECS, SGD, PIC; key outcomes included requesting (n=13), social communication (n=4), CB (n=4), vocalizations or speech (n=5), spelling (n=2), and word comprehension and production (n=1) •IRD across diagnostic groups: autism =0.83; autism + DD =0.70; autism + multiple comorbidities =0.53 •IRD across age groups: preschool =0.86; elementary =0.70; secondary = 0.64
Ganz et al^Citation20	Meta-analysis of ESCD studies of individuals with autism for effects of AAC on communication, social skills, CB, and academic skills (1980–2008)	IRD	•24 studies; 64% of children •Aided AAC: PECS, PIC, SGD; key outcomes included requests (n=13), social communication (n=4), CB (n=4), vocalizations or speech (n=5), spelling (n=2), use of SGD (n=2) •Using 84% CI for IRD: overall effects =0.99; communication =0.99; social skills =0.90, CB =0.80; academic skills =0.79 •PECS and SGD =0.99; PICs =0.61
Gevarter et al^Citation21	Systematic review of ESCD and group studies of individuals with developmental disabilities for AAC intervention component comparisons (2004–2012)	ESCD: meeting or approaching mastery criterion; group studies – statistical significance	•14 studies; seven of only autism; three with at least 50% autism •6/10 compared PECS to other AAC •Conclusive evidence: Phase I–II PECS; PECS + prompting + video modeling; function-preferred mands in Phases I, II acquired more rapidly than non-function-preferred mands •Preponderant evidence: PECS + Braille more effective than PECS only for child with visual impairment; pictures and photographs equal; 3/4 children more likely to use picture exchange for items with establishing operations; speech output, speech output with print, and print only effective for teaching spelling; function based more effective than non-function-based mands for setting generalization •All other comparisons were suggestive or inconclusive
Gevarter et al^Citation22	Systematic review of ESCD studies of individuals with developmental disabilities for comparisons of AAC modalities and outcomes (2004–2012)	Meeting or approaching mastery criterion	•28 studies; 15 of only autism; three with autism and other disability groups •Conclusive evidence: PECS/other picture system and SGD equal effectiveness for stages I & II PECS; pictures and microswitch equal, pictures preferred; speech + sign more effective than speech only, results in maintenance and generalization •Preponderant evidence: PECS/PIC vs SGD: PECS/PIC more effective and efficient (n=3) or no difference (n=5) to SGD; preference for SGD (n=2), for PECS/PIC (n=1); both microswitch and PIC reduced CB, preference for microswitch (n=1); PECS/PIC vs sign: both effective (n=7), PECS more efficient (n=3); more vocalizations with sign (n=3); SGD, PIC, microswitch: equal (n=2), SGD, PIC more effective (n=2), SGD preferred (n=1), sign harder to maintain (n=1); SGD, PIC, sign equal in effectiveness, sign less efficient (n=3), preference for SGD (n=1), SGD better maintained (n=3); PIC more effective than speech (n=1); speech, sign, echoic model most efficient combined, result in maintenance and generalization (n=2) •All other comparisons were suggestive or inconclusive
Ganz et al^Citation23	Meta-analysis of ESCD studies of individuals with autism foreffectiveness of aided AAC to bemoderated by research setting, type of AAC, and outcome variables (1980–2011)	IRD	•35 studies •IRD across settings: home (n=11) =0.70; general education (n=5) =0.84; special education (n=17) =0.71; therapy room (n=5) =0.66 •IRD across AAC type/outcomes: PECS/communication (n=15) =0.73; SGD/communication (n=8) =0.71; PICs/communication (n=7) =0.58; PECS/CB (n=2) =0.83; PECS/social skills (n=2) =0.77; SGDs/academic skills (n=2) =0.66; SGD/CB (n=2) =0.83
PECS
Preston and Carter^Citation24	Systematic review of ESCD and group studies of individuals with autism for efficacy of PECS (1992–2007)	ESCD: PND & PEM RCT: Cohen’s d	•27 studies; 24 of children only •ESCD (n=14): PND/PEM calculated for 9, overall PND range =55.6–100 (mean =78.5), picture exchange 68.7–100 (mean =90.0); overall PEM range =72.3–100; picture exchange 87.7–100 (mean =94.3) •RCT (n=1): d=0.63 for speech frequency; 0.50 for different words used •Other group studies (n=9): significant increases in communication behaviors •Maintenance data in five studies; three with positive findings •Generalization data in 15 studies, most with positive findings
Flippin et al^Citation25	Systematic review of ESCD and group studies of children with autism for efficacy of PECS in terms of communication and speech outcomes (1994–2009)	ESCD: ITSACORR software, PND Group studies: inferential statistics	•11 studies •Six studies taught to Stage III, two to Stage IV, two to Stage VII, one not reported •ESCD (n=8): communication outcomes (n=7), ITSACORR range =0.16–1.04 (mean =0.51, 95% CI [0.04–0.67]) indicating significant impact; PND range =64.4%–100% (mean =84.26%), indicating fairly effective (ES could not be determined n=2); speech outcomes (n=6), ES range =−1.45 to 0.26 (mean =0.17, 95% CI [−0.01 to 0.36]), PND range =6.5%–100% (mean =44.7%) indicating questionable effectiveness (ES not determined n=4) •Group studies (n=3): communication outcomes (n=3), ES 0.95, 0.65 suggesting strong and moderate, but inadequate quality (not determined n=1); speech outcomes (n=2), ES =0.05, 0.57 (negligible) •General lack of maintenance and generalization data
Hart and Banda^Citation26	Systematic review of ESCD of individuals with autism or other developmental disabilities for efficacy of PECS: communication, speech, CB, generalization, and social validity (1994–2007)	PND	•13 studies, 10 of children with autism •PECS Phases taught: I in six studies, II in five, III in five, IV in two, III in three, VI in two •Mands taught to 90% of children with autism •PECS compared to SGD (n=1) and sign (n=2), autism only •Communication outcomes: PND range =40%–100% (mean =83.8%, effective) •Reductions in CB (four children) PND range =53%–97% (mean =78.5, effective)
Tincani and Devis^Citation27	Systematic review of ESCD studies of individuals with autism or other developmental disabilities for efficacy of PECS: establishing functional communication and potential for interactions among learner and other variables (2002–2009)	PND	•16 studies; 14 of children with autism •Phases I–IV; PND mean =74.4 (SD =28.8) •Across all studies: PND preschool children =80.5, school age =71.3, adults =89.7; highest level mastered was Phase I for three participants, II for 6, III for 20, IV for 8; relationships between PND and diagnosis, sex, age, highest phase achieved, setting taught not significant
Ganz et al^Citation28	Meta-analysis of ESCD studies of individuals with autism for efficacy of PECS: (a) Differentiated across learner age, diagnosis, phase mastered (b) Differentiated across target (use of PECS) and non-target (CB, socialization, speech) (1980–2009)	IRD	•13 studies •94 separate effect sizes, IRD range =0.49–0.62 (mean =0.56) •Targeted – mean IRD =0.65 (0.59–0.73) •Non-targeted – mean IRD =0.61 (CB), 0.73 (socialization), 0.37 (speech) •IRD across age groups for targeted/non-targeted: preschool =0.79/0.48; elementary =0.60/0.44; secondary =0.49/0.32 •IRD across disability groups for targeted/non-targeted: autism =0.69/0.43; autism + DD =0.59/0.64; autism + multiple disabilities =0.44/none •IRD across PECS phases for targeted/non-targeted: three phases =0.65/0.78; four phases =0.33/0.33; six phases =0.84/0.45
SGD
van der Meer and Rispoli^Citation29	Systematic review of ESCD or group studies of children with autism into the efficacy of SGD as part of intervention (up to September 2009)	None	•23 studies (29 interventions) •Outcome to increase communication functions (mostly requests): seven conclusive, two inconclusive •Outcome to compare SGD to other AAC: four conclusive •Outcome to reduce CB: three conclusive •Outcome as use of device: one conclusive, two inconclusive •Other outcome: three conclusive, one inconclusive •15 studies used ABA principles, others used naturalistic strategies •20 studies – positive outcomes; seven included follow-up and 10 included generalization
Still et al^Citation30	Systematic review of studies into efficacy of high-tech devices for children with autism: requesting skills (up to July 2013)	None	•16 studies •iPod^® or iPad^® (n=5); PECS (n=7) manual signing (n=3) mostly as comparison modalities; others used dedicated SGDs; the key outcome was requests (n=15) or requests and other communicative behaviors (n=1) •15 were ESCD (mostly MBL) •14 studies included ABA teaching strategies; one used enhanced milieu teaching and one naturalistic intervention •Children learned from one to eight requests (mostly for preferred food or toys)
Lorah et al^Citation31	Systematic review of efficacy of handheld tablets as SGDs for individuals with autism or other developmental disabilities (2007–2014)	None	•17 studies; 12 of only children with autism, two studies mostly autism •Effectiveness of SGD to teach requests (n=12 studies), labeling (n=1), other functions (n=1) •More requests using SGD for 2/3 children with autism (n=1) •Comparisons across modalities, better for SGD (n=9 children), better for PIC or sign (n=4); preference for SGD (n=17) and for PIC (n=1)
Schlosser and Koul^Citation32	Systematic review to map research of the efficacy of SGD interventions for individuals with autism or other developmental disabilities (up to 2014)	ESCD: PND & PZD Group: Cohen’s d	•47 studies •Effects of SGD as part of a treatment package (n=26): requesting (n=4), PND range =43–100 (mean =0.79, fairly effective; reduction in CB (n=2), PZD =0–100 (mean =0.69, fair effectiveness); speech production PND =0 (2 ESCD), ES =0.21–0.62 (1 RCT, small to medium) •SGD vs other AAC (n=16): one at least preponderant, PND for SGD =100, for comparison AAC range =25–60 •SGD with and without speech (n=5) three preponderant, PND for spelling or requesting using speech =31–100 (mean =71), fairly effective; increasing child’s speech, ineffective
Effects on speech
Millar et al^Citation33	Systematic review to determine if AAC results in improved speech outcomes for individuals with developmental disabilities (1975–2003)	PND	•23 studies, 31% of 67 participants with autism •Six studies demonstrated experimental control: four children with autism, aged 3–12 (mean =6), two studies; PND for speech =21 for sign range =33–73 (mean =58) for aided (no speech output)
Schlosser and Wendt^Citation34	Systematic review to determine the effects of AAC on speech for children with autism (1975–2007)	ESCD: PND RCT: Cohen’s d	•11 studies •ESCD (n=9): PND range =0–100 across speech outcomes, 4/21 fairly or highly effective; 17/21 ineffective; PND range =0–100 for AAC outcomes, 12/18 fairly or highly effective, four questionable or ineffective, two not reported •Group (n=2): speech outcomes no differences across three sign and one speech only condition (n=1); PECS resulted in significantly more nonimitative speech than a non-AAC condition (n=1)
Partner training
Kent-Walsh et al^Citation35	Meta-analysis of ESCD of individuals with autism or other disabilities for efficacy of partner instruction: communication of individuals who use AAC and differences across variables (up to 2013)	IRD	•17 studies, six of children with autism •Communication partners were peers for nine children and parents for eight children •IRD for communication turns range =0.21–1.0 across 12 children (mean =0.66); for picture exchange = 0. 80, 1.0, 1.0 for each of three children; requests 0.61, 0.83 for two children •IRD across all studies: SGD =0.95, very large effects, non-SGD =0.72, large effects; poorest effects for adolescents, others yielded very large effects; participants with autism =0.69, moderate effects, compared to very large for other disabilities

Abbreviations: CB, challenging behaviors; DV, dependent variable; ESCD, experimental single case designs; IRD, improvement rate difference; IV, independent variable; MBL, multiple baseline; PCS, picture exchange communication system; PIC, picture-based communication other than PECS; PEM, percentage of data points exceeding the baseline mean; PND, percentage of nonoverlapping data; PZD, percentage of zero data; SGD, speech generating devices; RCT, randomized controlled trial; CI, confidence interval; SD, standard deviation.

Table 2 Effect size and quality indicators

Indicator	Definition	Categories
Effects sizes
PND^Citation39	Percentage of nonoverlapping data – percentage of data points that are above the highest baseline data point	Highly effective =91%–100% Effective =71%–90% Questionable =51%–70% Ineffective =<51%
PEM^Citation40	Percentage of treatment data points that are above the median baseline data point	Highly effective =91%–100% Moderately effective =70%–89% Minimally effective =50%–69% Ineffective =<50%
PZD	The first data point in the treatment that equals 0 and calculating the percentage of data points in treatment that stay at 0 from then on (used when the aim is to reduce a behavior)	High effectiveness =81%–100% Fair effectiveness =55%–80% Questionable effectiveness =18%–54% Ineffectiveness =<18%
IRD	IRD – the improvement rate of the baseline phase is subtracted from the improvement rate of the treatment phase	Large or very large effects =>0.75 Large effects =0.71–0.75 Moderate effects =0.51–0.70 Very small or questionable effects =<0.50
ITSACORR	Software program providing an F statistic and tests of changes in intercept and in slope for ESCD data, calculated as Glass’s delta^Citation41	Interpreted according to confidence intervals, determined for each outcome within included studies
Cohen’s d	Used for inferential statistics applied to group designs	Small effect =0.2–0.5 Moderate effect =0.5–0.8 Large effect =>0.8
Quality indicators
Indicators of rigor of ESCD based on Horner et al^Citation37	Indicators for core elements of participant and setting descriptions, dependent and independent variables, baseline, experimental control/internal validity, external validity, and social validity	Various ways to apply these were used across studies, some with scoring systems aStrong =90%+ Adequate =75%–90% Inadequate =<75%
Indicators of rigor for experimental and quasi-experimental group studies based on Gersten et al^Citation38	Indicators for core elements of underlying study rationale, participants/sampling, intervention descriptions and fidelity, outcome measures, data analysis	Strong =90%+ Adequate =75%–90% Inadequate =<75%
Certainty of evidence (four groups)	Features of the study are examined in terms of design, IOA, and treatment integrity	Conclusive evidence: sound design and at least adequate IOA and treatment integrity Preponderant evidence: minor design flaws and at least adequate IOA and treatment integrity Suggestive evidence: strong design or minor design flaws but inadequate IOA and/or treatment integrity Inconclusive: fatal design flaws
Certainty of evidence (dichotomous)	Quality of the study is considered to determine if experimental control has been demonstrated	Conclusive: recognized experimental design through systematic introduction and removal (eg, ABAB) or sequential introduction (eg, MBL) of intervention Inconclusive: nonexperimental design

Note:

a Indicates these categories used only by Flippin et al,²⁵ others applied the indicators more descriptively.

Abbreviations: PND, percentage of nonoverlapping data; PEM, percentage of data points exceeding the baseline mean; PZD, percentage of zero data; IRD, improvement rate difference; IOA, inter-observer agreement; ESCD, experimental single case designs; MBL, multiple baseline.

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