Predictors of Basic Reading Skills in High-Functioning Children with Autism Spectrum Disorder

Background: The number of high-functioning children identified with Autism Spectrum Disorder (ASD) has greatly increased in recent years.  The academic skills of these children show considerable variation; although word reading skills are often comparable, and sometimes superior, to those of typically developing children, some children struggle (Nation, Clarke, Wright & Williams, 2006).  It is important to update and expand our understanding of factors contributing to the development of basic reading skills because revised diagnostic criteria, small samples, large age and ability ranges, and varying outcome measures may limit the generalizability of older results.

Objectives: The purpose of this study was to document basic reading, cognitive and language skills in high-functioning children with ASD in the early grades and identify predictors of basic reading skills, such as executive functions and cognitive and language abilities.  Measures of cognitive flexibility were included as possible factors in the acquisition of reading since relationships between cognitive flexibility and reading have been reported for typically developing children (Cartwright, 2008), and children with ASD exhibit deficits in cognitive flexibility (Ozonoff, 1997).

Methods: Cognitive flexibility, literacy, language, and cognitive abilities were assessed in 63 children with ASD ages 6 through 9 using the Woodcock Johnson III and the Wisconsin Card Sorting Test.  All participants had nonverbal ability above 80, were enrolled in grades 1 - 4, and participated in the general curriculum. The sample was diverse for race, sex, parent education, community size, and educational program. A series of regression analyses was conducted to determine predictors of basic reading and whether cognitive flexibility explained any additional variation. 

Results: Basic reading skills varied greatly, with many children, especially first-graders, exhibiting above-average skills.  Verbal, nonverbal, language, phonemic awareness, and word reading skills were average for the group, but weaknesses were found in cognitive flexibility, cognitive efficiency, working memory, visual processing speed, listening comprehension, and retrieval fluency. 

Predictors of basic reading skills frequently noted in the literature, such as nonverbal ability and phonemic awareness, had strong relationships with the basic reading measures.  Moderate relationships were found with verbal ability, oral language, and working memory.

Cognitive, language, and phonemic awareness skills predicted basic reading to a similar extent as in typically developing children.  Specifically, five nonverbal, language, and phonemic awareness tests were able to predict 55 percent of the variance in word reading skills. Measures of cognitive flexibility did not contribute significantly to a regression model that included these other factors. 

Conclusions: Most high-functioning children with ASD in the early grades have good word reading skills, and predictors of reading are similar to those found in typically developing children. However, children with average verbal and nonverbal skills generally exhibit weaknesses in cognitive efficiency, cognitive flexibility, working memory, and listening comprehension.  Specialized instruction and accommodations for children with ASD, even those with above-average ability, are needed to address the impact of these weaknesses on academic learning and school success.  Further research is needed to determine whether word reading performance declines over time compared to age peers.