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C Putchat

Publications and source records attributed to C Putchat.

4 recordsLinked to original sources
PubMed1984

Motor control of schizophrenics--II. Manual control and tracking: sensory and motor deficits.

Manual control and tracking of 12 acute and chronic schizophrenics was tested for comparison with their performance in oculomotor tracking. Schizophrenics tended to be slower in a non-timed, non-tracking hand movement, and chronics made even slower movement when the experimental room was illuminated than when it was darkened. Chronics also had a significantly higher reaction time than normal controls. When tracking a constant-velocity visual target, all schizophrenics were significantly slower than normals to high-velocity (50 degrees and 60 degrees/s) targets only. When tracking a sinusoidally moving target, schizophrenics were not less accurate over-all but they showed less improvement than normals when room illumination gave visual information about background and hand position. This complex group of motor deficiencies of schizophrenics, along with their oculomotor control problems, suggests that they have sensory processing, attentional, and motor planning problems when performing orienting tasks.

Adult↗
PubMed1983

Parallel ocular and manual tracking responses to a continuously moving visual target.

Continuous ocular and manual tracking of the same visual target moving horizontally in sinusoids at 0.75 Hz was measured by lag, RMS Error, and Gain. The best measures of accuracy of tracking, error and lag, were remarkably similar in the two systems and were affected similarly by presence of a background and changes in predictability of target movement. Details of within-system performance varied despite the over-all parallels. Gain was different in adjustment of proportion of saccadic to pursuit movement was affected by the presence of the hand, even though this did not affect tracking accuracy. The over-all parallel of response adjustment suggests that a suprasystem decision-maker sets general response goals and each motor system adjusts output details to match these goals.

Journal Article↗
PubMedDate not supplied

Motor control of schizophrenics--I. Oculomotor control of schizophrenics: a deficit in sensory processing, not strictly in motor control.

An in-depth analysis of eye movements of schizophrenics has demonstrated defects in several oculomotor subsystems, likely due to processing of sensory information and not to problems in the motor system itself. Schizophrenic subjects made more pursuit tracking errors, due to higher RMS errors, larger phase lag, and more saccades in pursuit. When making saccadic movements they had normal reaction times, saccade velocity and intersaccadic pause, but made more double-jump saccades and overshot the target. Only some had inability to hold steady fixation, but all had an attentional problem in restraining an inappropriate eye movement. The multiple defects suggest a processing problem that is not strictly motor and does not fit any standard definition of attention.

Adult↗