NETTI Wheelchair: Does Dynamic Mode or Static Mode Affect the Sitting Position in Patients With Involuntary Movements ?

This study compares two modes of the NETTI wheelchair (dynamic or sitting) for patients with hyperkinetic syndromes, to discover which mode is the most comfortable and best suited to these patients. It is a prospective, single-center pilot study comparing two medical devices evaluated using SCED (Single Case Experimental Design) ABAB methodology: NETTI DYNAMIC chair in dynamic mode (intervention group; phase B) versus the same chair in static mode (control group; phase A). The subject will be his/her own control