Smooth pursuit in schizophrenia: abnormalities of open- and closed-loop responses.
A sample of 29 schizophrenia patients and 27 nonpsychiatric subjects were tested on measures of open- and closed-loop smooth-pursuit performance. Rashbass step-ramps were used to measure pursuit latency and open-loop gain. Regular ramps were used to calculate frequency and amplitude of both catch-up saccades and square-wave jerks, frequency of anticipatory saccades, and steady-state gain. Schizophrenia patients demonstrated lower open-loop gain than did nonpsychiatric subjects, an effect that was accentuated at faster target velocities. They also showed reduced steady-state gain, but only to 30 degrees/s right-moving targets. There was no evidence of saccadic abnormalities during smooth pursuit among the schizophrenia patients. These patients generated fewer square-wave jerks than did nonpsychiatric subjects for 10 degrees /s left-moving targets. These results suggest an abnormality of smooth-pursuit initiation among patients with schizophrenia.
Clementz
B A
BA
Department of Psychology, University of California-San Diego, La Jolla.
McDowell
J E
JE
D000328:Adult; D017831:Diagnosis, Dual (Psychiatry) / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D011569:Psychiatric Status Rating Scales; D011698:Pursuit, Smooth / Q000502:physiology*; D012438:Saccades / Q000502:physiology; D012565:Schizophrenic Psychology; D019966:Substance-Related Disorders / Q000523:psychology