Patterns of Impairment Among School Aged Children with ASD As Measured with a Computerized Executive Function Battery and Parent Report

Background: Among individuals with autism spectrum disorder (ASD), difficulties with executive function are observed, though the social demands of traditional laboratory tasks may contribute to differences in performance (Kenworthy et al., 2008). Flexibility and generativity impairments have been well documented, but investigations of working memory and inhibition have been mixed. The current project employed a computerized battery of behavioral tasks as well as parent report of executive dysfunction. The focus of the battery was examination of inhibition and verbal working memory. 

Objectives: To explore whether inhibition and working memory performance differed between children with ASD and typically developing comparison children. To investigate parent report of inhibition and working memory between groups. To evaluate the effect of age on performance in order to determine whether group differences may represent delays in development among young children with ASD.

Methods: Data collection is ongoing with data currently available for 16 children with ASD and 17 children with typical development (TD). Participants are 7 to 11 year-olds with full scale IQ of 80 or above. Inhibition was measured using a computerized version of the Stroop task and the Change task, which included a Go-Nogo block and a block of shifting from the dominant to a subdominant response (i.e. Change block). Working memory was measured using a computerized version of the Children’s Memory Scale Numbers subtest. Parent report of inhibition and working memory were also collected via the Behavioral Rating Inventory of Executive Function (BRIEF). Full scale IQ was covaried in all group comparisons.

Results: Preliminary results indicate group differences on percent accuracy between the neutral and incongruent conditions of the Stroop task, F(1, 21) = 11.2, p = .003. During the Change task, groups differed in accuracy during the Go-Nogo block, F(1, 30) = 4.6, p = .04, but did not significantly differ in the Change block. In terms of working memory, groups did not differ in their backward digit span performance. By parent report, children with ASD had more executive function difficulties overall, F(1, 24) = 31.7, p < .001, as well as reduced inhibition, F(1, 24) = 11.2, p = .003, and working memory, F(1, 24) = 11.1, p = .003. Among children with ASD, age was related to reaction time on the Stroop, r(11) = .62, p = .04, accuracy during the Go-Nogo block, r(16) = .76, p = .001, and the Change block, r(16) = .61, p= .01, of the Change task. Age did not relate with verbal working memory during the Digit Span.

Conclusions: Preliminary results suggest that children with ASD differed from those with TD on behavioral measures of inhibition in the face of conflict, but not verbal working memory. Parent report of inhibition, working memory, and overall executive function suggests more widespread difficulties among children with ASD relative to the comparison group. Interestingly, age corresponded with behavioral performance on measures of inhibition among children with ASD, providing support for a delay in this domain among young school aged children without significant cognitive impairment.