Auditory Working Memory and Wisconsin Card Sorting Test Performance in Schizophrenia

TLDR

Impaired WCST performance is evidence of frontal lobe dysfunction in schizophrenia, yet the specific cognitive processes responsible remain unclear. The study sought to determine whether a working memory deficit underlies impaired WCST performance in schizophrenia. Researchers compared 30 controls and 36 patients on a battery that included a novel letter‑number span task, and used regression to assess how LN span and other cognitive measures predicted WCST outcomes. Schizophrenia patients exhibited reduced LN span, which correlated strongly with WCST scores, and controlling for LN span eliminated group differences in WCST, indicating working memory drives WCST performance.

Abstract

Impaired Wisconsin Card Sorting Test (WCST) performance has been one critical piece of evidence suggesting frontal lobe dysfunction in schizophrenia. However, the specific cognitive processes underlying impaired performance have not been identified. Impaired WCST performance in schizophrenia might in part reflect a fundamental working memory deficit.We examined the performance of 30 normal subjects and 36 patients with schizophrenia on a neuropsychological battery including a novel measure of working memory-letter-number (LN) span.Patients with schizophrenia were impaired on LN span performance, which was also highly correlated with WCST performance (r = 0.74). Between-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, verbal fluency, and attention were predictive of perseveration.Working memory may be a critical determinant of one aspect of WCST performance in schizophrenia.