abstract
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Purpose: This article provides an analysis of group and single-case studies addressing augmentative and alternative communication (AAC) intervention with school-aged persons having autism spectrum disorder (ASD), and/or intellectual/developmental disabilities (IDD) resulting in complex communicative needs (CCNs). Specifically, we examined participant characteristics in group design studies reporting AAC intervention outcomes and how these compared to those reported in single-case experiments (SCED). Additionally, we compared the status of intervention features reported in group and SCED studies with respect to instructional strategies utilized.Participants: Participants included school-aged individuals with complex communicative needs who also experienced autism spectrum disorder (ASD) or ASD with an intellectual delay who utilized aided or unaided AAC.Methods: A systematic review using descriptive statistics and effect sizes was implemented.Results: Findings revealed that participant features such as race, ethnicity, and home language continue to be under-reported in both SCED and group design studies. Participants in SCED investigations more frequently used multiple communication modes when compared to participants in group studies. The status of pivotal skills such as imitation was sparsely reported in both types of studies. With respect to instructional features, group design studies were more apt to utilize clinical rather than educational or home settings when compared with SCED studies. Additionally, SCED studies were more apt to utilize instructional methods that closely adhered to instructional features more typically characterized as being associated with behavioral approaches. Conclusions: The authors discuss future research needs, practice implications, and a more detailed specification of treatment intensity parameters for future research.