Visuospatial working memory deficits and visual pursuit impairments are not directly related in schizophrenia.
OBJECTIVE
Patients with schizophrenia show deficits in visuospatial working memory and visual pursuit processes. It is currently unclear, however, whether both impairments are related to a common neuropathological origin. The purpose of the present study was therefore to examine the possible relations between the encoding and the discrimination of dynamic visuospatial stimuli in schizophrenia.


METHODS
Sixteen outpatients with schizophrenia and 16 control subjects were asked to encode complex disc displacements presented on a screen. After a delay, participants had to identify the previously presented disc trajectory from a choice of six static linear paths, among which were five incorrect paths. The precision of visual pursuit eye movements during the initial presentation of the dynamic stimulus was assessed. The fixations and scanning time in definite regions of the six paths presented during the discrimination phase were investigated.


RESULTS
In comparison with controls, patients showed poorer task performance, reduced pursuit accuracy during incorrect trials and less time scanning the correct stimulus or the incorrect paths approximating its global structure. Patients also spent less time scanning the leftmost portion of the correct path even when making a correct choice. The accuracy of visual pursuit and head movements, however, was not correlated with task performance.


CONCLUSIONS
The present study provides direct support for the hypothesis that active integration of visuospatial information within working memory is deficient in schizophrenia. In contrast, a general impairment of oculomotor mechanisms involved in smooth pursuit did not appear to be directly related to lower visuospatial working memory performance in schizophrenia.
Cocchi
Luca
L
Institute of Sport Science and Physical Education, Institute of Psychology, University of Lausanne, Switzerland. lcocchi@unimelb.edu.au
Bosisio
Francesca
F
Carter
Olivia
O
Wood
Stephen J
SJ
Berchtold
André
A
Conus
Philippe
P
Orita
Alina
A
Debbané
Martin
M
Schenk
Françoise
F
D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000523:psychology*; D009801:Oculomotor Muscles / Q000502:physiology; D011698:Pursuit, Smooth / Q000502:physiology*; D012559:Schizophrenia / Q000503:physiopathology*; D012565:Schizophrenic Psychology