Eye movement serves as a window into a part of the brain, which plays a major role in a number of neurological and development disorders, such as Autism, said John Foxe, Ph.D., director of the University of Rochester Medical Center Del Monte Neuroscience Institute and co-author of the study.
‘To provide effective care to autistic individuals, it is necessary to identify the specific phenotype of the disorder.’
Symptoms of Autism spectrum disorders (ASD)
Autism spectrum disorders (ASD) are characterized by a wide range of symptoms. These symptoms can vary from person to person depending on it's severity. This poses a great challenge for diagnosis and also in designing a course of treatment.
The first essential step in providing effective care to these individuals is to identify the specific phenotype of the disorder. For decades, neuroscience researchers have been focusing on eye movements and the mechanisms by which the brain controls and processes what we choose to look at.
The rapid eye movements like shifting our attention from one object to another is known as saccades that are essential to navigate, understand, and interact with the world around us. The saccades are rapid, precise, and accurate, redirecting the line of sight from one point of interest to another in healthy individuals.
Cerebellum, a densely-packed structure of neurons, is the area of the brain that controls these actions, that has a potential relevance of eye movement in individuals with Autism.
Traditionally, cerebellum is considered to play a vital role in the motor control. Now, the cerebellum is known to be essential to emotion and cognition, through its connections to the rest of the brain.
In the sub-population of individuals with Autism spectrum disorders (ASD), there is growing evidence that shows that the structure of the cerebellum has been altered.
Tracking Eye Movements of Individuals
The authors of this study have tracked the eye movements of individuals with Autism spectrum disorders (ASD) in a series of experiments.
The participants were asked to track a visual target, which appeared on different locations of the screen. The experiment was designed in such a way that the participant's focus "overshoots" the intended target.
The brain in a healthy individual adjusts eye movements correctly, as the task is repeated. But, the eye movements of individuals with ASD continued to miss the target, which shows that the sensory motor controls are impaired.
The inability of the brain to adjust the size of eye movement is a marker for cerebellum dysfunction. Apart from it, the brain can also help explain the communication and social interaction deficits that many individuals with ASD experience.
The findings from this research suggest that assessing the ability of people to adapt saccade amplitudes determines whether this function of the cerebellum is altered in Autism spectrum disorders (ASD).
Edward Freedman, Ph.D. an associate professor in the URMC Department of Neuroscience and co-author of the study said: "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."
- John Foxe, et.al. Eye Test Could Help Diagnose Autism. European Journal of Neuroscience 24 July (2017).