Educational level and age influence spatial working memory and Wisconsin Card Sorting Test performance differently: a controlled study in schizophrenic patients

The influence of educational level and age on executive function, as evalua ted by the Wisconsin Card Sorting Test (WCST), and 'working memory,' as eva luated by means of a visual-manual delayed-response task, has been investig ated in 25 schizophrenic patients and 35 healthy controls matched for age, Different patterns of correlations between educational level, age and cogni tive variables were seen for the 'working memory' task but not for the WCST , No significant correlations between the WCST and the 'working memory' tas k indexes have been observed. Based on multivariate analyses, poor performa nce of schizophrenic patients on working memory and executive function task s was observed; after covarying for the educational level, group difference s were no longer significant for executive functions, but the difference in 'working memory' performance persisted, The implications of sociodemograph ic variables as well as the role of statistical manipulation are evaluated and their differential impact on 'working memory' and executive functions i s proposed in further support of these neurocognitive constructs that may b e dissociable. (C) 2001 Elsevier Science Ireland Ltd, All rights reserved.