Assessment of single and bound features in a working memory task in schizophrenia

If disturbance of binding in long term memory is well established in schizophrenia, data concerning working memory maintenance are less clear. Feature binding in working memory was investigated in 19 patients with schizophrenia and 19 healthy controls. Binding was assessed by comparing two conditions in which participants had to retain four letters and four spatial locations. These features were presented either bound or separate. Results showed that both groups had better performances for bound than separate features, despite the fact that patients performed significantly worse than controls. When maintenance for isolated features was assessed, patients were severely disturbed for spatial locations but not for letters. Such a result suggests that reduced working memory performance in patients with schizophrenia for bound features is probably a consequence of a spatial deficit rather than a specific deficit of the binding process. Thus, not all form of binding are disturbed in schizophrenia.