Document Detail

Sinusoidal smooth pursuit eye tracking at different stimulus frequencies: position error and velocity error before catch-up saccades in schizophrenia and in major depressive disorder.
MedLine Citation:
PMID:  19670059     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: The aim of the present study was to ascertain the extent of impairment of position error and velocity error processing in eye tracking dysfunction in schizophrenic and depressive patients. METHOD: A total of 21 schizophrenic and 19 unipolar depressive patients and 21 healthy controls were subjected to an eye tracking test with electro-oculography using horizontal sinusoidal stimuli with frequencies of 0.2-0.7 Hz. Position error and velocity error were measured over a saccade-free range of 200 ms before catch-up saccades at 50 ms intervals. RESULTS: For position error, the schizophrenia patients displayed increased values particularly compared to controls, more rarely compared to depressive patients, depending on the stimulus frequency used. The increase in stimulus frequency did not lead to an increase in position error in any group of subjects over a prolonged period. For velocity error, in contrast, the study groups differed only in a few, isolated pre-saccadic intervals. The increase in stimulus frequency, however, led to an increase in velocity error in the schizophrenia patients over the entire 200 ms interval. The depressive patients did not differ notably from the controls, neither in terms of position error nor velocity error. CONCLUSIONS: Eye tracking dysfunction in schizophrenia can be described as follows with regard to position error and velocity error: On the one hand, there is an increased position error tolerance largely independent of stimulus frequency, possibly due to an impairment of processing localization information. On the other hand, velocity processing is more severely impaired by an increase in stimulus frequency.
Karin Fabisch; Werner Fitz; Hans Fabisch; Alexandra Haas-Krammer; Gunter Klug; Stephan Zapotoczky; Hans-Peter Kapfhammer
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  The Australian and New Zealand journal of psychiatry     Volume:  43     ISSN:  1440-1614     ISO Abbreviation:  Aust N Z J Psychiatry     Publication Date:  2009 Sep 
Date Detail:
Created Date:  2009-08-11     Completed Date:  2009-10-21     Revised Date:  2009-11-11    
Medline Journal Info:
Nlm Unique ID:  0111052     Medline TA:  Aust N Z J Psychiatry     Country:  England    
Other Details:
Languages:  eng     Pagination:  855-65     Citation Subset:  IM    
Department of Psychiatry, Medical University of Graz, Auenbruggerplatz 31, Graz, Austria.
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MeSH Terms
Case-Control Studies
Depressive Disorder, Major / complications,  physiopathology*
Ocular Motility Disorders / complications,  physiopathology*
Pursuit, Smooth / physiology*
Saccades / physiology*
Schizophrenia / complications,  physiopathology*

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