Show summary
Many individuals with intellectual disabilities who use augmentative and alternative communication (AAC) are not provided with opportunities to acquire early literacy skills, which are essential for developing functional reading abilities. Contributing factors include a lack of evidence-based reading programs tailored for AAC users, insufficient professional expertise, and low instructional expectations. Acquiring functional reading skills is critical, as it enhances communication and fosters greater independence, such as through text-based communication aids. Research suggests that reading interventions can support both literacy development and communicative competence.
This dissertation examines the effects of a reading intervention targeting components essential to early reading instruction for students with intellectual disabilities who use AAC. It also explores the current state of the field, methods employed, and conditions that may facilitate reading development. The dissertation comprises four studies addressing these questions from different perspectives.
Article I presents a reading intervention involving 40 students with intellectual disabilities who use AAC, aged 6–14 years, none of whom could decode syllables or words prior to the intervention. A multiple single-case design with randomized multiple baselines was used. Students were divided into four groups, each commencing the intervention at different times, with 13 to 18 months of instructional exposure following 2 to 5 baseline measurements. The intervention used adapted materials based on Accessible Literacy Learning (Light & McNaughton, 2011), implemented through the Lesing for alle ("Reading for All") program. Students were assessed in early reading skills over 18 months, the McArthur-Bates Communicative Development Inventories (MB-CDI) and a standardized reading test (OL64). While statistical significance emerged only for sound-blending, individual outcomes revealed that nearly half of the students developed phonological awareness. Thirteen students demonstrated reading proficiency on adapted and standardized tests, and an additional three showed phonological reading skills in program-based assessments. These students shared a common strength: mastery of many letter-sound correspondences at the onset of the intervention.
Article II used a subset of the Article I dataset to investigate associations between early literacy skills and students’ receptive and expressive vocabulary, as measured by the MB-CDI. Earlier research on the role of vocabulary in early literacy development among AAC users with intellectual disabilities is limited and inconclusive. Findings from this study highlight the positive relationship between both receptive and expressive vocabulary and early literacy skills, particularly sound blending and letter-sound correspondence. However, vocabulary expressed through AAC systems did not correlate with early literacy outcomes.
Article III provides a systematic review of reading interventions for students with intellectual disabilities who use AAC. Given that most studies in this population employ single-case research designs, and prior reviews often address either intellectual disabilities or AAC use independently, this review focused specifically on the intersection of both. Findings revealed a limited number of studies, few participants, and minimal coverage of reading components. Only four studies met the evidence standards established by the What Works Clearinghouse (2022).
Article IV investigated teachers’ reading practices in both mainstream and special schools, emphasizing the instructional methods, strategies, and materials used with students with autism who use AAC. It also examined teacher expectations regarding students' potential to acquire literacy skills. A survey was distributed to 932 schools in Norway, targeting educators currently or previously working with this student population. Results aligned with international research pointing to a lack of professional competence, low expectations, and insufficient evidence-based reading materials and assessments designed for AAC users.
Theory and research consistently underscore the need to provide students with intellectual disabilities who use AAC the opportunity to acquire early reading skills, which are foundational to later literacy and functional reading. Functional literacy offers many benefits, most notably more independent communication through text-based aids. Many AAC users rely entirely on symbols and pre-programmed content, limiting their autonomy. As noted in Study IV, teachers in both educational settings reported limited training in literacy instruction for this group and expressed a desire for more targeted professional development. The absence of standardized assessments for early literacy skills among AAC users further complicates instructional planning and the establishment of realistic goals.
To promote equitable access to literacy instruction, larger research initiatives are needed to increase awareness, raise expectations, improve school-based competence, and develop evidence-based materials and assessments tailored to AAC users. This dissertation examined the barriers to reading development for this population and sought to identify facilitators of effective instruction. Future research should prioritize comprehensive studies that incorporate additional literacy components, such as reading comprehension, and employ rigorous methodologies while accounting for the heterogeneity within this population.
Ultimately, the goal is to establish clear standards and guidelines for how students with intellectual disabilities who use AAC can achieve functional reading skills. Accommodating individual differences is essential, but first, we must determine what works for whom.
