Background: Augmentative and alternative communication (AAC) is often used as an intervention on speech production in children with autism or pervasive developmental disorder-not otherwise specified (PDD-NOS). However many families and service providers are concerned that ACC may hinder natural speech development.
Objectives: To conduct a systematic review of single-subject studies on the effects of AAC intervention on speech production in children with autism and PDD-NOS.
Search strategy: The authors conducted reference checks for previous studies on ACC and searched several databases: CINAHL, ERIC, LLBA and PsychINFO.
Selection criteria: The authors selected studies about ACC interventions with participants who were not functionally speaking prior to the intervention. All studies were published between 1975 and 2007.
Data collection and analysis: Selected studies were reviewed and categorized by author(s), purpose of study, participants, design, results, and evaluation of evidence. Evaluation of evidence was conducted according to several methodological criteria.
Main results: The authors included nine single-subject experimental design studies (27 participants) and 2 group studies (98 participants) in the review. The findings indicated that ACC does not impede speech production in children with autism and PDD-NOS. While ACC increased speech production, the authors report a modest effect size for the interventions.
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.