Associations between receptive and expressive vocabulary and early literacy in young students with intellectual disabilities using AAC.

Researchers studied how well children with intellectual disabilities and autism who use communication devices understand the connection between vocabulary and reading skills. They found that children who could express more words were better at recognizing letter sounds and blending sounds together. However, children with both autism and intellectual disability had more difficulty achieving top scores in early reading skills compared to other groups.

This cross-sectional study examined vocabulary-literacy relationships in 39 students (ages 6-14) with intellectual disabilities, autism, and/or Down syndrome who use AAC. Using correlation analyses and generalized linear models, researchers found significant correlations between expressive vocabulary and both letter-sound knowledge and sound blending skills. Contrary to expectations, receptive and expressive vocabulary showed no correlation with early literacy skills overall. However, binomial models highlighted receptive vocabulary's importance in early literacy development.

Students with autism and intellectual disability using AAC demonstrated higher negative probability of achieving maximum early literacy scores, suggesting additional challenges in this subgroup.

Findings suggest targeting expressive vocabulary may support letter-sound knowledge and phonological skills in AAC users. Students with co-occurring autism and intellectual disability may require additional literacy support. Receptive vocabulary remains important despite lack of direct correlation with literacy measures.

Small sample size (n=39) limits generalizability. Cross-sectional design prevents causal inferences. Heterogeneous population (intellectual disabilities, autism, Down syndrome) may confound results. Study methodology not fully described in abstract. Age range is quite broad (6-14 years) which may introduce developmental variability.

This study examined the associations between receptive and expressive vocabulary and early literacy skills (i.e., phonological awareness and letter-sound knowledge) among 39 students aged 6-14 years with intellectual disabilities, autism, and/or Down syndrome who use augmentative and alternative communication (AAC). Receptive and expressive vocabulary are identified as a key risk factor for developing reading skills in students with intellectual disabilities who use AAC. Spearman's correlation analyses and generalized linear models were conducted throughout this non-experimental investigation to examine the association between receptive and expressive vocabulary, phonological awareness (sound blending and initial sound recognition), and letter-sound knowledge. Findings revealed a significant correlation between expressive vocabulary (i.e., words children can use in speech) and both letter-sound knowledge and sound blending, contrary to prior research.

Additionally, students' receptive and expressive vocabulary showed no correlation with their early literacy skills. Binomial Generalized Linear Models (mixed-effects models) highlighted the importance of receptive vocabulary in early literacy development. Furthermore, looking at the differences within the sample, students with autism and intellectual disability requiring AAC had a higher negative probability of maximum scores in early literacy skills. These findings deepen understanding of how the correlations between receptive and expressive vocabulary relate to early literacy skills.

This may contribute to more targeted interventions and provide implications for practitioners and their teaching within receptive and expressive vocabulary and early literacy components, which will benefit this population in further reading development.