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Saccadic distractibility in first-episode schizophrenia.
S B Hutton1, E M Joyce, T R E Barnes
1Division of Neuroscience and Psychological Medicine, Imperial College School of Medicine, Charing Cross Hospital, London, UK.
Neuropsychologia
|May 7, 2002
Summary
Schizophrenia patients make more errors in antisaccade tasks as cognitive demands rise. This suggests a specific deficit in strategic control, not just fixation inability, impacting eye movement control in schizophrenia.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Psychiatry
Background:
- Antisaccade errors are more frequent in schizophrenia patients, but the cause is not fully understood.
- It is unclear if these errors stem from general fixation difficulties or specific deficits in strategic action control.
Purpose of the Study:
- To investigate whether antisaccade errors in schizophrenia are due to general fixation impairment or specific deficits in cognitive control.
- To differentiate between a general inability to maintain fixation and a specific deficit in the strategic control of internally generated actions.
Main Methods:
- Patients with first-episode schizophrenia and healthy controls performed three saccadic paradigms.
- Paradigms varied in concurrent cognitive demands while requiring suppression of a prepotent saccade.
- Tasks included the antisaccade paradigm, assessing eye movement control under different cognitive loads.
Main Results:
- Both groups showed increased errors with higher cognitive demands.
- The increase in errors was significantly steeper in schizophrenic patients compared to controls.
- Schizophrenic patients could inhibit prepotent saccades equally well as controls in low-demand conditions.
Conclusions:
- Antisaccade errors in schizophrenia appear linked to a specific deficit in strategic control, exacerbated by cognitive load.
- Findings suggest potential roles for reduced working memory resources and impaired motor preparation in schizophrenia-related eye movement abnormalities.