Comparison of executive functions in high-function autistic children and their typical matched peers

Several hypotheses have been proposed to explain cognitive dysfunctions in children with high-function autism including executive dysfunction hypothesis. The main goal of this study was to examine differences in executive functions (namely, sustained attention, selective attention, and response inhibition) between children with high-function autism and their normal matched peers. In this cross-sectional study, 16 children with high-function autisms were compared with 16 typically developing counterparts. Word-Color Stroop, Go/Not Go and Continuous Performance Tests were respectively administered to assess selective attention, inhibition, and sustained attention. Data were statistically analyzed via independent t test using SPSS software version 18 at the significance level of 0.01. No significant differences were found in correct responses (P = 0.65) and average reaction time (P = 0.08) between children with autism and typical developing group during Word-Color Stroop test. In Continuous Performance Test, there was no significant differences in omission (P = 0.60) and commission (P = 0.64) errors between children with autism and their typical matched peers. However, a significant difference was observed in average reaction time (P < 0.01) implying higher speed in autistic subjects. Regarding Go/No Go test, there was no significant difference between two groups in average reaction time in the Go stage (P = 0.70), correct responses (P = 0.33) and average reaction time (P = 0.52) in the No Go stage. There was, however, significant difference between two groups in correct responses of Go stage (P = 0.00) indicating better performance of typical group. Response inhibition (proponent and motor) and sustained attention are those components of cognitive executive functions which remain intact in high-function autism. Intact response inhibition in autism may be due to their week reading comprehension, specific affected brain areas and the type of task used. Intact sustained attention may imply a tendency for focusing on specific stimuli and displaying repetitive behaviours among autistic children.