Acquisition, Preference and Follow-up Comparison Across Three AAC Modalities Taught to Two Children with Autism Spectrum Disorder (summary)



Many people diagnosed with autism spectrum disorder (ASD) fail to develop enough speech to meet their everyday communication needs. Augmentative and alternative communication (AAC) has been used successfully with some of this population. Possible AAC strategies for children with ASD include the use of manual signing, picture exchange and speech generating devices (SGDs). This leads to the question of which of these systems should be taught to any individual.

It has been suggested that it might be beneficial to trial all of these options in the early stages of intervention. It would also be useful to look at children’s performance using the different strategies following intervention, in generalisation and maintenance phases.

This study is related to a similar one (McLay et al, 2015), focussing on the teaching of ‘more’ to children with ASD.


What did they do?

The study aimed to partially replicate the 2015 paper using a slightly different sequence of intervention phases.

The research questions were; would an intervention be effective in teaching two children with ASD to request continuation of toy play using 3 different AAC modalities? Would this learning be maintained over time? Would the child show a preference for one or more of the 3 systems? And would that preference remain stable over time?

Two boys aged 5 and 10 took part in the study. Both had an ASD diagnosis and severe receptive and expressive language difficulties. They had no previous experience of signing, picture exchange or SGDs, but were able to use an iPad to play games.

The boys were taught to request ‘more’ play with highly motivating toys using each of the three AAC methods. Prior to intervention beginning a baseline level of their use of this request was established. During intervention they were taught to use the 3 AAC systems in separate sessions with prompting of their responses.

The intervention was followed by long-term follow up 5 to 7 months after the last intervention session, at this time no prompts were given.

After each baseline, intervention and follow up session preferences for any of the 3 AAC systems was checked.


 What did they find?

The older boy used the SGD twice during baseline sessions but did not use either of the other AAC options. With intervention he was able to use the SGD and picture exchange to the level of 80% correct and unprompted responses, but did not meet this level using signing.

On follow up he made only one request and used picture exchange.

When being assessed for a preferred AAC modality he selected the SGD on 55% of trials, made no selection on 40%, used picture exchange 3% and signed 2%, in a total of 50 trials.

The younger boy used the SGD during baseline assessment but did not use the other systems. During intervention he reached the 80% level only with picture exchange but also used both of the other systems. On follow up the SGD was used correctly 100% of the time in two sessions and picture exchange 80% of the time in one session. When preferences were investigated he chose the SGD 61% of the time, picture exchange 18% and sign 5%. He made no choice on 16% of trials in a total of 62 probes.



The findings were consistent with the earlier McLay et al study. Signing was the least successful/ preferred AAC modality. The participants generally showed a preference for SGDs over picture exchange or signing.

The long gap between the final intervention session and follow up, with no maintenance activities led to a decrease in performance compared to the intervention phase.

The authors suggest that whilst the children’s performance with the SGD was not more successful than picture exchange they might have preferred it due to the voice output which possibly acted as a reinforcer.



This was a very small study, although similar to another carried out by the same lead author. The request being taught, ‘more’, is a very early communication skill which the participants might have been able to express through other prelinguistic behaviour reducing the need to use AAC systems.

Things you may want to look into:

Comparing Acquisition, Generalization, Maintenance, and Preference Across Three AAC Options in Four Children with Autism Spectrum Disorder

Acquisition, Preference, and Follow-up Data on the Use of Three AAC Options by Four Boys with Developmental Disability/Delay

Speech-Generating Devices Used at Home by Children With Autism Spectrum Disorders

Facilitating requesting skills using high-tech augmentative and alternative communication devices with individuals with autism spectrum disorders: A systematic review

A Review and Analysis of the Picture Exchange Communication System (PECS) for Individuals with Autism Spectrum Disorders Using a Paradigm of Communication Competence

A Comparison of PECS and iPad to Teach Requesting to Pre-schoolers with Autistic Spectrum Disorders

Interaction of Participant Characteristics and Type of AAC With Individuals With ASD: A Meta-AnalysisEvaluating Picture Exchange and the iPad™ as a Speech Generating Device to Teach Communication to Young Children with Autism


Added to site September 2016