Accelerated time course of saccadic inhibition of return in individuals with autism spectrum disorders.

The inhibition of return (IOR) refers the observer's slower response time when the target stimulus appears on the previously attended location. In the present study, we examined the time course of saccadic IOR by using five stimuli onset asynchronies (SOAs) in a group of adults with autism spectrum disorders (ASDs) and a comparison group. The results showed that the IOR effect occurred earlier (300 ms SOA) in participants with ASDs, relative to the comparison participants (500 and 700 ms SOAs). The ASD group also committed a greater number of anticipatory saccades, which positively correlated with scores on restricted and repetitive behaviors, as assessed by the Autism Diagnostic Interview-Revised (ADI-R; Lord et al. in J Autism Dev Disord 24:659-685, 1994). These findings reveal an accelerated time course for saccadic IOR along with diminished volitional oculomotor control in participants with ASDs. We discussed these results with reference to the atypical and the superior visual search abilities often reported in this population.