Early Reading Interventions for Children with Intellectual Disabilities Using AAC: A Systematic Review of Single-Case Designs

Children with intellectual disability and/or autism spectrum disorder who use augmentative and alternative communication are often excluded from evidence-based reading instruction. Early reading skills are essential, yet assumptions about speech and cognitive prerequisites have limited research on reading interventions for AAC users. Consequently, the evidence base guiding early reading instruction for this population remains underdeveloped. This systematic review examined evidence from single‑case research evaluating early reading interventions for children with ID who use AAC. Systematic searches were conducted in seven databases (including ERIC, PsycINFO, and MEDLINE) through March 2023. Studies were included if they employed single‑case experimental designs to evaluate early reading interventions for children with ID who used AAC. Methodological quality was assessed using the What Works Clearinghouse (WWC, 2022) single‑case design standards. Results were synthesised using a structured narrative synthesis. Seven studies involving 20 participants met the inclusion criteria. Four studies met WWC standards without reservation. Across studies, positive effects were consistently reported for letter–sound correspondence and phonological awareness, whereas findings for decoding were mixed. The evidence base was limited by small samples and a narrow focus on early reading components. Single‑case evidence suggests that children with ID who use AAC can benefit from early reading interventions, particularly for foundational alphabetic skills. However, the small number of studies and limited outcome scope highlight the need for more comprehensive and methodologically robust research.