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

Background: Eye movements provide a window into cognitive processing. Deficits in oculomotor control (i.e. suppressing reflexive saccades) have been shown to relate to language ability in ASD. In addition to language problems, an increasing number of studies have highlighted motor difficulties in this population. Of note, research supports a link between motor skill and aspects of oculomotor control, such as smooth pursuit (e.g. the ability to track an object); as reported in a population of children with a core motor impairment. However, at present, very little is known about the relationship between motor and oculomotor function in ASD.

Objectives: The present study set out to measure motor ability and the integrity of the oculomotor system in ASD. The study aimed to determine if eye movements can differentiate between children with ASD and controls; and to investigate 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. ASD diagnosis was confirmed using the Autism Diagnostic Observation Schedule (ADOS-2), and Full Scale IQ (WISC-IV) and motor competency were assessed (using the Movement Assessment Battery for Children, MABC-2). Children completed four short tasks designed to assess oculomotor function: fixation, smooth pursuit, pro- and anti-saccades. Eye movements were recorded using the Eyelink 1000 (SR-research).

Results: Preliminary analyses reveal that children with ASD demonstrated poorer fixation stability and made more drifts away from the visual target than their peers. Children with ASD were comparable to their peers on the slow speed measure of smooth pursuit, but demonstrated lower pursuit gain than the controls in a faster pursuit task. Reflexive eye movement (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 those 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 neural mechanisms involved in this disorder. Moreover, the findings highlight the need to examine co-occurring difficulties, such as poor motor skill, when interpreting eye tracking data.