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Smooth pursuit in schizophrenia: Abnormalities of open‐ and closed‐loop responses
Author(s) -
CLEMENTZ BRETT A.,
McDOWELL JENNIFER E.
Publication year - 1994
Publication title -
psychophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.661
H-Index - 156
eISSN - 1469-8986
pISSN - 0048-5772
DOI - 10.1111/j.1469-8986.1994.tb01027.x
Subject(s) - psychology , smooth pursuit , saccadic masking , schizophrenia (object oriented programming) , psychosis , audiology , latency (audio) , abnormality , physical medicine and rehabilitation , neuroscience , eye movement , psychiatry , medicine , electrical engineering , engineering
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%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% left‐moving targets. These results suggest an abnormality of smooth‐pursuit initiation among patients with schizophrenia.