Motion and pattern cortical potentials in adults with high-functioning autism spectrum disorder

Abstract

Autism spectrum disorder (ASD) is a condition in which visual perception to both static and moving stimuli is altered. The aim of this study was to investigate the early cortical responses of subjects with ASD to simple patterns and moving radial rings using visual evoked potentials (VEPs). Male ASD participants (n=9) and typically developing (TD) individuals (n=7) were matched for full, performance and verbal IQ (p>0.263). VEPs were recorded to the pattern reversing checks of 50' side length presented with Michelson contrasts of 98 and 10% and to the onset of motion-either expansion or contraction of low-contrast concentric rings (33.3% duty cycle at 10% contrast). There were no significant differences between groups in the VEPs elicited by pattern reversal checkerboards of high (98%) or low (10%) contrast. The ASD group had a significantly larger N160 peak (1.85 x) amplitude to motion onset VEPs elicited by the expansion of radial rings (p=0.001). No differences were evident in contraction VEP peak amplitudes nor in the latencies of the motion onset N160 peaks. There was no evidence of a response that could be associated with adaptation to the motion stimulus in the interstimulus interval following an expansion or contraction phase of the rings. These data support a difference in processing of motion onset stimuli in this adult high-functioning ASD group compared to the TD group.