ATYPICAL SPATIAL ASYMMETRY OF FRONTAL TASKS PERFORMANCE IN YOUNG BOYS WITH AUTISM

Background: Along with the growing body of work on EF deficit in young children with autism there is evidence that the phenomenon of spatial neglect may contribute to their failure to succeed in performance of EF tasks.

Objectives:  The study examined the hypothesis that failure to disengage attention to the left spatial location from previously important or relevant information can contribute to the poor performance of autistic children on EF-tasks.

Methods: A group of 21 boys diagnosed with autism (BWA), aged 3 to 7 years, was compared to the same number of age-matched typically developing boys (TDB). Two delayed-response-type tasks were administered: Spatial Reversal task (SR) that taps prepotent response inhibition and Delayed Alternation task (DA) as a measure of working memory. IQ-level was assessed by Kaufman Assessment Battery for Children (K-ABC-I) or Psychoeducational Profile (PEP).

Results: BWA did not exhibit any deficit in inhibition during the performance on the SR task whereas on the DA task BWA performed significantly poorer than TDB. There was the significant difference between BWA and TDB in the age regression slope: the total number of errors decreased as a function of age in BWA while in TDB it remained stable across the age period under the study. Most importantly, BWA, unlike TDB, demonstrated the strong right-sided bias in the performance of both EF tasks. Whereas the number of errors in both SR and DA tasks in TDB was perfectly symmetrical, BWA made significantly more errors when the successfully retrieved bait was shifted from the right to the left side than vise versa. 

Conclusions: These data suggest that BWA aged 3 to 7 years have partial deficit of working memory but no impairment of inhibitory control. Asymmetrical performance of both tasks implies that young boys with autism have difficulties with attention disengagement from right to left visual hemi-field.