Feedback about previous action improves executive functioning in schizophrenia: An analysis of maze solving behaviour.

Disturbances of executive functions (EF) in schizophrenia have received special attention during the past years, but there is still an ongoing debate whether impairment in EF tasks can be linked to deficits of EF themselves or if they rather reflect impairment of other cognitive functions such as working memory processes that are additionally required for task solving. In the present study, we analyzed whether impairments in the maintenance of previous processing assumed to be related to working memory contribute to the impairments in EF tasks seen in schizophrenia. Twenty-five schizophrenic patients treated with atypical antipsychotic agents and 25 healthy controls matched according to age, sex, and education were instructed to solve novel two-dimensional maze tasks by steering a pen through a system of paths. Low demands on maintaining previous actions by giving feedback on preceding movements (visualising the trace of the pen) were contrasted with high demands, i.e. without such a trace of past processing. Without feedback of previous action, task solution was less successful and the control of motor action was deficient in schizophrenic patients. With feedback, both domains of behaviour improved to the level of healthy controls at the costs of higher time demands. The behaviour of healthy controls was not influenced by the experimental manipulation. Lower demands on the maintenance of previous action seem to enable schizophrenic patients to perform executive functions successfully. But data suggest that task solving of schizophrenic patients is characterized by alterations in the coordination of executive functions with other cognitive processes.