AUDITORY WORKING-MEMORY AND WISCONSIN CARD SORTING TEST-PERFORMANCE IN SCHIZOPHRENIA

Background: Impaired Wisconsin Card Sorting Test (WCST) performance ha s been one critical piece of evidence suggesting frontal lobe dysfunct ion in schizophrenia. However, the specific cognitive processes underl ying impaired performance have not been identified. Impaired WCST perf ormance in schizophrenia might in part reflect a fundamental working m emory deficit. Method: We examined the performance of 30 normal subjec ts and 36 patients with schizophrenia on a neuropsychological battery including a novel measure of working memory-letter-number (IN) span. R esults: Patients with schizophrenia were impaired on LN span performan ce, which was also highly correlated with WCST performance (r=0.74). B etween-group WCST differences were eliminated when we covaried LN span . Regression analyses suggested that LN span performance predicted the WCST category achieved score, whereas measures of set shifting, verba l fluency, and attention were predictive of perseveration. Conclusion: Working memory may be a critical determinant of one aspect of WCST pe rformance in schizophrenia.