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Smooth pursuit eye tracking over a structured background in first-episode schizophrenic patients.

Hutton, S. B. and Crawford, Trevor J. and Kennard, C. and Barnes, T. R. E. and Joyce, E. M. (2000) Smooth pursuit eye tracking over a structured background in first-episode schizophrenic patients. European Archives of Psychiatry & Clinial Neurosciences, 250 (5). pp. 221-225. ISSN 1433-8491

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Abstract

Whilst most laboratory smooth pursuit tasks are performed in the dark, in everyday life pursuit commonly occurs over a structured background. This background provides a powerful stimulus to the optokinetic reflex (OKR), inducing a background “drag” on pursuit eye movements. An inability to inhibit the influence of the OKR may be a contributing factor to the dysfunctional pursuit performance observed in many schizophrenic patients. Smooth pursuit performance was measured in 23 first-episode schizophrenic patients and 23 healthy controls matched for age and estimated IQ, both in the dark and over a structured background (a random checkerboard of black and white squares). Velocity gain was measured, as well as the number and size of corrective saccades (catch-up saccades) and intrusive saccades (anticipatory saccades and square wave jerks). Overall, schizophrenic patients had lower velocity gain and made more catch-up saccades than controls. The effect of the background was to lower velocity gain and increase the number of catch-up saccades to the same extent in schizophrenic patients and controls. There were no significant interactions between group and background effect. These results suggest that, although their overall level of performance was worse, the schizophrenic patients were as able as controls to inhibit the effect of the OKR. Since lesion studies show that inhibition of the OKR requires intact inferior parietal regions in man (Lawden et al., 1995), one hypothesis is that the parietal component of smooth pursuit may be intact in schizophrenia.

Item Type: Article
Journal or Publication Title: European Archives of Psychiatry & Clinial Neurosciences
Uncontrolled Keywords: Smooth pursuit · Schizophrenia · Optokinetic response · Structured background · Inhibition
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Departments: Faculty of Science and Technology > Psychology
ID Code: 11162
Deposited By: Dr Trevor Crawford
Deposited On: 04 Aug 2008 13:09
Refereed?: Yes
Published?: Published
Last Modified: 26 Jul 2012 14:57
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/11162

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