Effects of augmentative and alternative communication intervention on speech production in children with autism: a systematic review.

PURPOSE: This systematic review aimed to determine the effects of augmentative and alternative communication (AAC) intervention on speech production in children with autism or pervasive developmental disorder-not otherwise specified.
METHOD: A systematic review methodology was utilized to limit bias in searching, selecting, coding, and synthesizing relevant treatment studies. This involved a multifaceted search for studies written between 1975 and May 2007 using various bibliographic databases, dissertation databases, hand searches of selected journals and published compilations of AAC theses and dissertations, and ancestry searches. To be included, studies had to meet stringent criteria. A coding manual and form facilitated data extraction in terms of participant characteristics, treatment characteristics, design and measurement, and outcomes.
RESULTS: Nine single-subject experimental design (27 participants) and 2 group studies (98 participants) were included. Results indicated that AAC interventions do not impede speech production. In fact, most studies reported an increase in speech production. However, in-depth analyses revealed that the gains were rather modest.
CONCLUSIONS: Although AAC interventions do not appear to impede speech production and may result in increased speech production, the modest gains observed require realistic expectations among clinicians and other stakeholders. Future research should be more hypothesis driven and aim to identify predictive child characteristics, such as prior speech imitation and object exploration skills.