To Simulate Prismatic Adaptation in Healthy Subject : a Technical Innovation in Favour of Autonomy and Independence in Daily Life Following a Brain Injury

Unilateral neglect is a neuropsychological disorder reflected by a disturbance in the spatial exploration and distribution of directed attention affecting the contralateral part of space and body relatively to the brain lesion. The chronic aspect of this pathology leads to a poor progression following rehabilitation and a decreased independence of patients in daily life. Thus, it is necessary to set up efficient and long lasting therapies for unilateral neglect patients to improve their daily quality of life. Prismatic adaptation is now a classical method which allows patients to improve their neglect through corrective pointing movements in response to a lateral displacement of the visual field. A large and growing body of literature has investigated prismatic adaptation as a very promising rehabilitation method, improving both visuomotor and cognitive features of unilateral neglect. However, its effects are somehow irregular and clinical applications of this method are still limited. The necessity for patients to come to the hospital to take advantage of prismatic adaption sessions draws some limitations about our knowledge concerning 1) the temporal dynamic of prism adaptation effects on a long-term basis and 2) the optimal duration of treatment (most of the time constrained by the hospitalization duration) and its therapeutical effects on a very long-term basis. Moreover, a large number of patients also suffer from motor deficits which reduce the possibility to optimize the prismatic adaptation session.

Thus, the aim of this project is to develop and validate others modalities of prismatic adaptation which can be applied at home and for a longer duration. These modalities should allow the investigator to get insights about the temporal dynamic of prismatic adaptation on the cognitive system. First, the investigator will investigate the effects of a prismatic adaptation modality using virtual reality to reproduce the lateral displacement induced by the prismatic goggles. He will also investigate prismatic adaptation induced by motor imagery, i.e. with mental representations of pointing movements without concomitant motor execution. This project could enhance the fundamental knowledge and enable to design new modalities of therapeutical use of prismatic adaptation (virtual or imaged) so as to allow a home-based treatment and follow-up. Thus, the aim of this project is to demonstrate the implication of similar mechanisms through different modalities (virtual and imaged compared to classical application) and the feasibility of these new modalities of healthy subjects. Thereafter, the aim will be to use knowledge acquired during this project to set up clinical trials to test for the efficiency of these modalities on a long-term basis in a pathological population.