Supplementary Material for: Improving Early Literacy Skills for Autistic Children who use High Tech AAC: Effects of a Parent-Delivered Intervention

Introduction: Literacy skills contribute to meaningful societal participation and maximize expressive language for AAC users; however, AAC users continue to experience pervasively low levels of literacy achievement. Many extrinsic factors related to the instructional approaches, such as reliance on oral responding and the need for extensive retrofitting of materials, create significant barriers to literacy instruction for AAC users. There is a need for innovative, evidence-informed literacy interventions that incorporate adaptations and systematic instruction to improve outcomes for this population.
Methods: A single case experimental design with a multiple baseline across participants design was used to investigate the effects of the ALL app, implemented by trained parents, on the acquisition and generalization of three phonics-based early literacy skills (i.e., sound blending, decoding, and sight words), with threefour children who had minimal or no speech and used high-tech AAC. The ALL app was implemented by parents who were virtually trained, and progress was monitored remotely by researchers. Social validity data was also collected from parents.
Results: All participants demonstrated progress in the three skills targeted, as well as generalization in sound blending, demonstrated by effect sizes from large to very large. The intervention was also efficient, with these gains occurring with only ten weeks of instruction. These gains are notable given that the participants each entered the intervention knowing less than ten sight words and less than five letter sounds. Perception data from the parents is also shared.
Conclusion: Future research and practice should aim to providing simultaneous instruction in foundational and interrelated literacy skills, support motivation and participation of AAC users through use of adaptations and numerous opportunities to apply skills in the context of meaningful shared literacy experiences, and use parent-implemented, direct instruction with explicit practice of target skills.