DEFECTIVE RECOGNITION OF ONE'S OWN ACTIONS IN SCHIZOPHRENIC PATIENTS
Résumé
Objective : The possibility that delusion of influence could be related to abnormal recognition of one's own actions was investigated in persons with schizophrenia. Method : Influenced (N=6) and non-influenced (N=18) patients with schizophrenia were compared to normal subjects (N=29) in an action recognition task. The image of a virtual right hand holding a joystick was presented to the subjects through a mirror so that it was superimposed to their real hand holding a real joystick. Subjects executed discrete movements in different directions. Angular biases and temporal delays were randomly introduced in some trials, such that the movements of the virtual hand departed from the movement executed by the subjects. After each trial, subjects had to decide whether the movement they saw was their own or not. Results: Compared to the comparison subjects, both patient groups made significantly more recognition errors in trials with temporal delays. In trials with angular biases, the error rate of influenced patients significantly differed from that of comparison subjects and from that of the non-influenced patients. Conclusions : These findings support the hypothesis that delusion of influence is associated with a quantifiable difficulty in attributing actions to their author. This difficulty may be related to a specific impairment of a neural action attribution system.