A Systematic review of AAC interventions using speech generating devices for autistic preschoolers

Many autistic¹ children experience communication challenges. Augmentative and alternative communication (AAC) can function as a primary or supportive mode of communication, and interventions incorporating AAC have a positive impact on the communication skills of autistic children. This systematic review investigated intervention studies using speech generating devices to enhance the expressive language of autistic preschoolers. Specifically, research questions addressed the (a) expressive communication skills and functions; (b) instructional strategies; (c) impact of interventions; and (d) ecological validity of the included studies. After an extensive search process, twenty studies from 1998 to 2023 met the inclusion criteria. Study characteristics were extracted, social and ecological validity were evaluated, and results were described using effect sizes and visual analysis. The majority targeted requesting (n=14) and the remaining addressed communication acts across diverse functions (n=6). Eleven of the studies demonstrated moderate to strong effects. Most interventions were multicomponent, including a variety of strategies, with prompting being the most common. Fewer than half of the studies met the full criteria for ecological validity, and only seven measured social validity. Implications for the field are provided including a call to action for researchers to evaluate interventions to support communication across diverse functions.