The Influence of Social Communication on Written Expression in School-Age, Higher-Functioning Children with Autism Spectrum Disorders

Background: Higher-functioning children with ASD (HFASD) remain affected by social-communication impairments. However, we know little about how these difficulties affect school performance or how to leverage curriculums to improve their social-communication development. It may be that the reading comprehension and written expression problems exhibited by children with HFASD are components of the social communication phenotype of school-age HFASD and, therefore, may be important targets for school-based intervention (e.g., McIntyre et al., 2016; Randi et al., 2010; Zajic et al., in press). This study examined the hypothesis that impairments in written expression reflect an important part of the social-communication phenotype of school-aged children with HFASD.

Objectives: The study tested the hypotheses that a) 8–16-year-old children with HFASD would display specific writing impairments compared to either a clinical or a typical control sample, and b) HFASD group differences in writing performance would be significantly associated with differences in symptom severity.

Methods: The participants were 65 children with HFASD, 34 children with ADHD, and 34 children with typical development (TD). ASD symptoms were confirmed with the ADOS-2; ADHD symptoms were confirmed with the Conners-3. IQ was assessed with the WASI-II. Writing was assessed with the Word Count and Theme Development and Text Organization subscales of the Wechsler Individual Achievement Test, 3^rd Edition (WIAT-III) and the Contextual Conventions (CC) and Story Composition (SC) subscales of the Test of Written Language, 4^th Edition (TOWL-4). Factors that may influence writing performance were assessed with the Story Memory Recall task of the Wide Range Assessment of Memory and Learning-2 and the Reading Comprehension measure of the Gray Oral Reading Test-5.

Results: A MANCOVA controlling for IQ revealed a Diagnostic Group effect on the writing measures, F(8,242)=3.15, p<.002, Wilks' Λ=.898, partial η²=.09. Univariate effects were observed for the CC, F(2,124)=6.44, p<.002, partial η²=.09, and for SC, F(2,124)=10.1, p<.001, partial η²=.14. Pair-wise comparisons with Bonferroni correction indicated that the HFASD and ADHD groups performed worse than the TD group on the CC scale (p<.002, p<.02), but the two clinical groups did not differ. The HFASD group performed worse than either the ADHD (p<.02) or the TD group (p<.001) on SS, but the latter two groups did not differ. No reliable differences were observed on the two WIAT-III writing scales. ADOS-2 Total scores and TOWL-4 SC scores were correlated in the HFASD group, r=-.39, p<.002, and this association held when controlling for IQ. SC was also associated with Reading Comprehension, r=.38, and Story Memory, r=.53, p<.001, in the HFASD group.

Conclusions: This study revealed evidence of a syndrome-specific deficit in writing development in children with HFASD compared to clinical and typically developing controls. Differences in writing were also significantly correlated with symptom presentation consistent with the hypothesis that impairment in writing development is associated with the development of the social-communication phenotype of school-aged children with HFASD. Possible intervention implications will be discussed.