OCULAR MOTOR-RESPONSES TO UNPREDICTABLE AND PREDICTABLE SMOOTH-PURSUIT STIMULI AMONG PATIENTS WITH OBSESSIVE-COMPULSIVE DISORDER

This study was conducted to evaluate the smooth pursuit system functio ning of patients with obsessive-compulsive disorder (OCD). For Study 1 , 12 subjects with OCD and 12 nonpsychiatric subjects were administere d 9-deg-per-sec ramp stimuli to elicit smooth pursuit eye movements. c onsistent with a previous report, patients with OCD did not significan tly differ from nonpsychiatric subjects on pursuit gain, or frequency of corrective and intrusive saccades. Patients with OCD, however, had smaller catch-up saccades during smooth pursuit than nonpsychiatric su bjects. For Study 2, 12 subjects with OCD and 12 nonpsychiatric subjec ts were administered 2 different triangle wave stimuli with target vel ocities of 12 (0.2 Hz) deg per sec and 24 (0.4 Hz) deg per sec, Subjec ts with OCD and nonpsychiatric subjects did not significantly differ o n any variable in the slow target velocity condition, When following 2 4-deg-per-sec targets, however, patients with OCD had significantly lo wer pursuit gain than the nonpsychiatric subjects. Results from Study 1 and 2 are consistent with the hypothesis that patients with OCD have a modest smooth pursuit deficit that is elicited only while following faster velocity targets.