EEG and Behavioral Correlates of Temporal Prediction in the Tactile Modality in Schizophrenia

Patients with schizophrenia have disturbances in their sense of self, particularly their bodily self. Disorders of the sense of self are central to schizophrenia and are of interest because they are thought to be present prior to the development of the disorder, when only a few attenuated symptoms signal a risk of developing psychosis. Finding markers related to the sense of self would make it possible to predict which subjects, among those with minimal psychotic symptoms, will develop psychosis, and thus to better adapt management. Disturbances in the experience of the passage of time that accompany disturbances in the sense of self have been described particularly in subjects at risk of developing psychosis, and would predict the onset of the pathology. However, as with alterations in the sense of self, it can be difficult to get patients to describe their disturbances in the experience of time, and objective measures are required to facilitate detection of these disturbances. In the present protocol an objective measure of temporal perception mechanisms will be tested in relation to the sense of self. The tests used in the protocol assess subjects' abilities to benefit from the passage of time and to use these abilities to predict and prepare for the occurrence of an event. The investigators have previously shown that patients with impaired bodily sense of self do not benefit from the passage of time to prepare themselves to process information in the future. The present protocol is aimed at developing a measure more sensitive to the patients' disorders by adding tactile measures.