The abandonment of central executive? Fractionation of executive functions in patients with schizophrenia

Abstract

OBJECTIVE: The purpose of this study was to examine the phenomenon of fractionation of executive attention performance in schizophrenia. METHODS: A group of 90 schizophrenic patients (74 men, 16 women) were recruited. Patients were given a set of frontal executive function sensitive tests to assess initiation, sustained attention, switching and flexibility, impulsivity and disinhbition, strategy allocation and planning. They were also given information subscale and memory subtests of the WAIS-R and WMS-R. We analyzed individual patient’s executive attentional performance with the normative data from our laboratory. Summary scores for all specific executive attention components were computed. For each component, participants were classified as having impairment with their test performance below 1.5 standard deviations of the norms of the corresponding test. RESULTS: The findings showed that there were 27.8% (n = 25) cases demonstrated impaired performance in all executive components and 5.6% (n = 5) exhibited intact performance in all components. About 18.9% (n = 17), 16.7% (n = 15), 21.1% (n = 19), and 10% (n = 9) showed intact performance in 1 component, 2 components, 3 components, and 4 components, respectively. No significant differences were found among the groups in terms of education, gender, and duration of illness. Multiple univariate ANCOVA using age, information and medication as covariates indicated significant differences among the groups in terms of clinical symptoms and non-executive functions. CONCLUSION: These findings suggest there is a fractionation of central executive in this clinical group.