Smooth-pursuit eye movement and saccadic intrusions in obsessive-compulsive disorder

Although several reports agree that smooth-pursuit eye movement (SPEM) is abnormal in some obsessive-compulsive disordered (OCD) patients, differences between treatments and lack of accuracy in control selection make the results controversial. Although reduced gain seems the most accepted abnormality, the characteristics of saccadic disruption of smooth pursuit are as yet unspecified. SPEMs in 21 OCD patients (DSM-III-R) and 21 healthy subjects recruited from the community were studied through a multiple target velocity task. The two groups were individually matched on age, gender, and level of education. None of the subjects had a history of substance dependence apart from the smokers who refrained from smoking in the 2 hours prior to the test. A significantly lower SPEM gain and increased number and frequency of anticipatory saccades (ASs) was found in OCD patients as compared with control subjects. No relationship emerged between eye movement abnormalities and clinical variables explored.