Deficits of spatial working memory in chronic schizophrenia

Abstract

This study tests the hypothesis that deficits of spatial working memory are an inherent trait in schizophrenic patients, regardless of their clinical status. The participants were 22 chronic schizophrenic patients, 11 schizophrenic patients in remission, and 22 normal adults. All participants were asked to track the outlines of a square presented on a computer screen in a clockwise direction while moving their eyes at their preferred rate and then to reproduce the square on a blank computer screen (Task A). Thereafter, the computer only displayed the four corners of the same square. The corners were displayed sequentially in a clockwise direction, one at a time at equal intervals. They were asked first to track the four corners of the square and then to reproduce the square on a blank computer screen (Task B). Chronic schizophrenic patients reproduced tasks A and B with significantly greater distortions than normal controls. The extent of their distortions was significantly greater during the reproduction of Task A than Task B. By contrast, schizophrenic patients in remission reproduced both Tasks A and B with the same accuracy as normal controls. On the basis of these findings it is concluded that the chronic schizophrenic patients have a significant deficit of spatial working memory, but that this deficit can be ameliorated by cognitive interventions and is therefore not an immutable trait in schizophrenia.