Smooth pursuit eye movements in schizophrenics: Quantitative measurements with the search-coil technique

S. Levin*, A. Luebke, D. S. Zee, T. C. Hain, D. A. Robinson, P. S. Holzman

*Corresponding author for this work

Research output: Contribution to journalArticle

70 Scopus citations

Abstract

Eye movements of five schizophrenic and five normal subjects were measured with the magnetic-field search-coil technique. Subjects followed targets moving smoothly at various speeds, either unpredictably in a step-ramp fashion or predictably in a triangular wave. The tracking stimulus was either a small dot or a large, richly-textured image that occupied a large portion of the visual field. Tracking by schizophrenics was abnormal; it was punctuated by catch-up saccades that corrected for smooth following movements of inadequate velocity. We did not, however, find saccadic intrusions, such as square wave jerks. Under all tracking conditions steady-state gains (eye velocity/target velocity) and, in the case of step-ramps, averarage acceleration in the first 120 ms were lower in patients than in normal subjects. The differences were most pronounced for tracking of the small target, moving at the highest speed tested (30 degree/s), in the nonpredictable, step-ramp waveform. With this stimulus mean steady-state gain was 0.36 (SD ± 0.12) for the schizophrenic patients and 0.73 (SD ± 0.11) for the normal subjects. When the target was changed to the large-field stimulus or moved in a predictable (triangular-wave) fashion, tracking improved in both patients and normal subjects, and even more so when these features were combined.

Original languageEnglish (US)
Pages (from-to)195-206
Number of pages12
JournalJournal of Psychiatric Research
Volume22
Issue number3
DOIs
StatePublished - Jan 1 1988

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Biological Psychiatry

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