Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common neurobehavioral disorders diagnosed in children. Because there isn't a simple test to diagnose ADHD, misdiagnosis is also common.
Now researchers from Tel Aviv University have discovered an objective indicator for ADHD - involuntary eye movements. Using an eye tracking system, researchers studied the eye movements of 22 people with ADHD and 22 people without the disorder. The participants' involuntary eye movements were tracked as they underwent a computerized test called the Test of Variables of Attention, or TOVA. The participants with ADHD took the test twice - once without ADHD medication and then again with methlyphenidate.
Following the testing researchers saw a direct link between ADHD and the "inability to suppress eye movement in the anticipation of visual stimuli." They also noted that after participants with ADHD took methlyphenidate, their performance was similar to participants without the disorder.
"We had two objectives going into this research," said researcher Dr. Moshe Fried. "The first was to provide a new diagnostic tool for ADHD, and the second was to test whether ADHD medication really works — and we found that it does. There was a significant difference between the two groups, and between the two sets of tests taken by ADHD participants un-medicated and later medicated."
The study, "ADHD subjects fail to suppress eye blinks and microsaccades while anticipating visual stimuli but recover with medication," is published in the journal Vision Research.