A study of visual and auditory verbal working memory in schizophrenic patients compared to healthy subjects.

Impaired working memory (WM) performance is considered as a central feature of schizophrenia. Divided into two components, verbal and spatial, WM has been shown to involve frontal and parietal regions. Verbal WM can be tested either visually or aurally. The present study aimed to test schizophrenic patients in both visual and auditory verbal WM in order to assess a possible distinct pattern of alteration of these two modalities. Twenty-four schizophrenic patients and 24 healthy controls were compared with 2-back continuous visual and auditory verbal WM testing. Both groups were also tested on a neuropsychological battery including Wisconsin Card Sorting Test (WCST). Schizophrenic patients were less efficient in both verbal WM tests. When taking age and educational level as covariates and both WM modalities as dependent variables, there was no differential effect of modalities across groups. In further exploratory analyses, partial correlations brought association between verbal WM and psychosocial adaptation, WCST and length of illness. These results suggest a similar pattern of alteration of both modalities of verbal WM in schizophrenic patients. The implications of this finding are discussed.