Could you diagnose autism by looking into someone’s eyes? New research suggests that certain rapid eye movements could be a tell of the developmental disorder.
These rapid eye movements the research investigates are not the well-known kind that are within the human sleep cycle, but rather are the movements our eyes make as we shift focus to another location in our field of vision. The saccades, as they are officially called, are an important neurological function that helps us interact with people and objects around us. “They are crucial for navigating, and also for orienting visual attention to spatial locations containing pertinent information,” according to a study in the European Journal of Neuroscience, and in that way they may also provide some insight into autism.
“When these neural mechanisms fail, due to damage or disease or developmental disorder, the resultant changes in eye movements can suggest specific computational errors that may be responsible, and highlight brain regions where these computations are thought to occur,” the authors explain.
In healthy people, saccades are fast and accurate. But the scientists observed these rapid eye movements in people with autism as they followed an object on a screen and found that they look different.
The University of Rochester Medical Center explained that the researchers designed their experiment so that a person’s eyes would naturally overshoot the target as they tried to track the visual. As the experiment went on, a healthy person’s eyes would adjust to overcome that design and make more precise movements, while people with autism did not — their eyes kept missing the target.
This tells researchers “that the sensory motor controls in the cerebellum responsible for eye movement were impaired,” the medical center said. “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 [autism spectrum disorder] experience.”
That’s because the cerebellum, while responsible for the rapid eye movements and other motor functions, is also crucial for emotional and cognitive functions.
“These findings build upon a growing field of research that show that eye movement could serve as a window into a part of the brain that plays a role in a number of neurological and [developmental] disorders, such as autism,” study co-author John Foxe said in the university statement.
The study is careful to note, however, that one size does not fit all, since autism varies so widely between patients. There are people who have more mild symptoms and there are people who are severely impaired by the developmental disorder, which is characterized by difficulty interacting and communicating with others.
Analyzing rapid eye movements, therefore, could prove helpful for detecting autism early on in some patients and not others. And it follows that other diagnostic and treatment strategies also would be effective only for certain groups.
“Because of the wide range of symptoms expressed in individuals with autism spectrum disorder (ASD) and their idiosyncratic severity, it is unlikely that a single remedial approach will be universally effective,” the authors wrote. “Resolution of this dilemma requires identifying subgroups within the autism spectrum, based on symptom set and severity, on an underlying neuro-structural difference, and on specific behavioral dysfunction. This will provide critical insight into the disorder and may lead to better diagnoses, and more targeted remediation in these subphenotypes of people with ASD.”