Motor Ability and Oculomotor Function in Children with an Autism Spectrum Disorder

摘要

Background: Deficits in oculomotor control (i.e. suppressing reflexive saccades) have been shown to relate to language ability in Autism Spectrum Disorders. In addition to language problems, an increasing number of studies highlight motor difficulties in this population. Of note, research on supports a link between motor skill and aspects of oculomotor control, such as smooth pursuit, in children with a core motor impairment. However, very little is known about this possible relationship in ASD. The present study examined the integrity of the oculomotor system in children with and without ASD; and investigated the relationship between motor skill and oculomotor function. Methods: Twenty-two children with ASD, aged 7-10 years, were compared to 22 typically-developing children matched by age. An ASD diagnosis was confirmed with background measures, and IQ and general motor competency were assessed. Children completed four tasks examining oculomotor function: fixation, horizontal smooth pursuit, pro- and anti-saccades. Eye movements were recorded using the Eyelink 1000 (SR-research). Results: Children with ASD demonstrated poorer fixation stability and made more drifts away from the visual target than their peers. They were comparable to their peers on the slow speed measure of smooth pursuit, but demonstrated poorer pursuit gain in a faster task. Reflexive eye movements (pro-saccades) were similar across the two groups. However, children with ASD had more difficulty with the anti-saccade task, making many errors. Individual case analyses revealed that the children with ASD that had poorer motor skills also performed worse on the measures of fixation and smooth pursuit. Conclusions: The findings are the first demonstration of a link between motor and oculomotor difficulties in children with ASD. Further examination of oculomotor dysfunction in this population may help to identify specific neural mechanisms. Moreover, the findings highlight the need to consider co-occurring difficulties (i.e. motor skill) when interpreting eye tracking data.