TY - JOUR
T1 - Smooth pursuit eye movements in schizophrenics
T2 - Quantitative measurements with the search-coil technique
AU - Levin, S.
AU - Luebke, A.
AU - Zee, D. S.
AU - Hain, T. C.
AU - Robinson, D. A.
AU - Holzman, P. S.
PY - 1988
Y1 - 1988
N2 - 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.
AB - 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.
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U2 - 10.1016/0022-3956(88)90005-2
DO - 10.1016/0022-3956(88)90005-2
M3 - Article
C2 - 3225789
AN - SCOPUS:0023680101
VL - 22
SP - 195
EP - 206
JO - Journal of Psychiatric Research
JF - Journal of Psychiatric Research
SN - 0022-3956
IS - 3
ER -