A technique that measures tiny movements of the eyes may help scientists better understand and perhaps eventually improve assessment of ADHD (attention-deficit/hyperactivity disorder), says a study.

Emerging evidence shows that small involuntary eye movements (saccades and microsaccades) are a promising new tool for shedding light on the hidden workings of mental processes like attention and anticipation, cognitive processes that are often impaired in individuals with ADHD. The new study published in the journal Psychological Science suggests that carefully tracking eye movements offers a new method for empirically monitoring temporal expectation in people with ADHD."The eye is restless and eye movements occur constantly, even when observers try to avoid them. Our study shows that this continuous stream of eye movements is temporarily paused before an anticipated visual event," said senior author on the study Shlomit Yuval-Greenberg, Assistant Professor at Tel Aviv University in Israel. 

"This attenuation in eye movements can be used as an estimate for whether and when the occurrence of regular events was indeed predicted," Yuval-Greenberg said. The researchers found that those without a diagnosis of ADHD tended to have different patterns of eye movements compared with individuals who had an ADHD diagnosis."We found that individuals with ADHD tended to not attenuate their eye movements before a predictable event, which suggests that they were not able to predict the event and/or to act upon predictions," Yuval-Greenberg explained.The findings indicate that careful analysis of eye movements may offer an objective measure to complement other tools used for diagnosis and assessing treatment efficacy.