The purpose of this scoping review was to (a) map the research evidence on the effectiveness of augmentative and alternative communication (AAC) interventions using speech output technologies (e.g., speech-generating devices, mobile technologies with AAC-specific applications, talking word processors) for individuals with autism spectrum disorders, (b) identify gaps in the existing literature, and (c) posit directions for future research. Outcomes related to speech, language, and communication were considered. A total of 48 studies (47 single case experimental designs and 1 randomized control trial) involving 187 individuals were included. Results were reviewed in terms of three study groupings: (a) studies that evaluated the effectiveness of treatment packages involving speech output, (b) studies comparing one treatment package with speech output to other AAC modalities, and (c) studies comparing the presence with the absence of speech output. The state of the evidence base is discussed and several directions for future research are posited.
Keywords: Assistive technology; Augmentative and alternative communication; Autism spectrum disorders; Mobile technologies; Scoping review; Speech output technology; Speech-generating devices; Synthetic speech.