Pursuit eye movement dysfunction in obsessive-compulsive disorder.

Disturbances in neural circuitry including the basal ganglia and prefrontal cortex have been hypothesized to be a cause of obsessive-compulsive disorder (OCD). Because eye movements are often impaired in neurologic diseases affecting these brain areas, oculomotor functioning was assessed in 17 unmedicated patients with OCD and in 25 normal controls. As compared with control subjects, patients with OCD demonstrated low-gain (slow) pursuit eye movements and an increased frequency of square wave jerk intrusions, but no increase in anticipatory saccades. In addition, several OCD patients showed an unusual pattern of intrusive, brief epochs of high-gain (fast) pursuit lasting on the order of 50 to 130 msec. These epochs of fast pursuit moved the eyes ahead of the target being tracked, and were terminated by corrective reversal saccades. Studies of eye movement abnormalities may provide an informative neurophysiologic approach for studying disturbances in basal ganglia and frontal cortical function that have been observed in functional neuroimaging and neuropsychological studies of OCD.