Visual Information-Processing in Deficit and Nondeficit Schizophrenic Patients

Hong, Kyung Sue; Kim, Jae Gyeong

Abstract

OBJECTIVES
Previous studies of cognitive impairment in schizophrenia suggest that negative syndrome can be characterized by specific impairments in visual information-processing. We examined the possibility of such cognitive impairments as a a trait marker of 'deficit' syndrome group characterized by persistent primary negative symptoms or schizophrenic patients as a whole.
METHODS
The subjects were 35 schizophrenic patients in partial or full remission state and the controls were 25 volunteers screened for major mental illnesses in their 2nd degree relatives. The patients were divided into deficit & nondeficit groups based on Schedule for the Deficit Syndrome and they showed positive, depressive or extrapyramidal symptoms of minimal to mild degree. Performance on various cognitive tasks associated with visual information-processing was examined.
RESULTS
Deficit and nondeficit groups showed no significant difference in age of onset, duration of illness, the severity of positive and depressive symptoms and dose of antipsychotics. Deficit group performed significantly less well than normal control group on Continuous Attention Test. Significant difference was found between the patients groups and normal control group on Vigilance Test, Signal-Detection Test, and in decision time of Reaction Unit Tests. There were no significant differences among three groups on the tasks of visual immediate memory, visual analysis, motor reaction, and fine motor control. No cognitive variable was correlated to duration of illness, the severity of positive and depressive symptoms, general psychopathology, and dose of antipsychotics.
CONCLUSIONS
The results suggest that deficit syndrome might be characterized by the impairment of continuous attention to simple visual stimuli. Impaired vigilance to infrequent visual stimuli, selective auention to visual stimuli and delayed decision time in simple information-processing tasks which were not related to various clinical variables were suggested to be cognitive markers of schizophrenia.