Novel eye test may help diagnose autism

New York, July 25 : A new eye test that can reveal impairment in cerebellum may help identify people with autism spectrum disorders (ASD), researchers say.

The cerebellum -- part of the brain which coordinates and regulates muscular activity -- controls the actions of rapid eye movements made when shifting attention from one object to another, known as saccades.

In healthy individuals, these saccades are rapid, precise, and accurate, redirecting the line of sight from one point of interest to another.

Conversely, in individuals with autism, the activity was found impaired, as a result of alteration in the structure of the cerebellum, said researchers from the University of Rochester in New York, US.

For the study, detailed in the European Journal of Neuroscience, the team tracked the eye movements of individuals with ASD.

The participants were asked to track a visual target that appeared in different locations on the screen. The experiment was designed in a manner that often caused the participant's focus to "overshoot" the intended target.

In healthy individuals, the brain would correctly adjust eye movements as the task is repeated. However, the eye movements of individuals with ASD continued to miss the target suggesting that the sensory motor controls in the cerebellum responsible for eye movement were impaired.

The inability of the brain to adjust the size of eye movement may not only be a marker for cerebellum dysfunction, but it may also help explain the communication and social interaction deficits that many individuals with ASD experience.

"These findings suggest that assessing the ability of people to adapt saccade amplitudes is one way to determine whether this function of the cerebellum is altered in ASD," said co-author Edward Freedman, Associate Professor at the university.

"If these deficits do turn out to be a consistent finding in a sub-group of children with ASD, this raises the possibility that saccade adaptation measures may have utility as a method that will allow early detection of this disorder," Freedman added.