Tel Aviv University researchers have developed an accurate diagnostic tool for the Attention Deficit Hyperactivity Disorder (ADHD) - the most commonly diagnosed and misdiagnosed - behavioral disorder in children.
The researchers said that currently there are no reliable physiological markers to diagnose ADHD. Doctors generally diagnose the disorder by examining the medical and social history of a patient and his/her, observing the child's behaviour and through discussions of possible symptoms. But an incorrect evaluation can lead to overmedication with Ritalin (methylphenidate).
The new study has found that involuntary eye movements can accurately predict the presence of ADHD.
For the study, the researchers used an eye-tracking system to monitor the involuntary eye movements of two groups of 22 adults undertaking an ADHD diagnostic computer test called the Test of Variables of Attention (TOVA). The exercise, which lasted 22 minutes, was repeated twice by each participant.
The first group of participants, diagnosed with ADHD, first took the test un-medicated and then after the influence of methylphenidate. The second group without ADHD constituted the control group.
The researchers found a direct association between ADHD and the inability to suppress eye movement in the anticipation of visual stimuli. They also observed an enhanced performance by participants taking methylphenidate, which regularized the suppression of involuntary eye movements to the average level of the control group.
"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," Researcher Dr. Moshe Fried said in a statement. "This test is affordable and accessible, rendering it a practical and foolproof tool for medical professionals. Eye movements tracked in this test are involuntary, so they constitute a sound physiological marker of ADHD."
"Our study also reflected that methylphenidate does work. It is certainly not a placebo, as some have suggested."
The finding is published in Vision Research.
