Durable improvements in Wisconsin Card Sorting Test performance in schizophrenic patients

Abstract

We examined the potential reversibility of cognitive deficits of schizophrenic patients in performing the Wisconsin Card Sorting Test (WCST), a neuropsychological measure of frontal lobe performance. The sample comprised 34 DSM III-R schizophrenic patients, who were randomly assigned to one of three groups, viz. two experimental groups and one control group, and were tested on six consecutive occasions. The results show that schizophrenic patients, selected on their poor WCST performance, could dramatically improve their performances by an elaborate procedural test training. They were even able to sustain these improvements over a 2-week period. The addition of monetary reinforcement to the test training was less effective than training alone. This reinforcement had an inhibiting effect on the training. Our results suggest that frontal lobe deficits in schizophrenia can be reduced and that a central deficit in schizophrenic WCST performance is a stable dysfunction in concept formation. For now it remains to be seen that this deficit in concept formation is remediable.