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

Inclusion Criteria: * Patient with involuntary extension movements with a frequency greater than (\>) 3/hour and requiring at least one wheelchair repositioning every 2 hours. * Patient using a wheelchair and requiring to be in a seated position at least 4 hours per day. * Patient and/or representative with free and informed consent. * Patient and/or representative having signed the consent form. * Patient affiliated or beneficiary of a health insurance plan. * Patient over 16 years of age (≥16 years). Exclusion Criteria: * Patient unable to sit in chair for at least 3 hours a day. * Patient unable to sit in the chair without the use of a thermoformed corset. * Patients weighing over 135kg. * Patient participating in a drug study. * Patient in an exclusion period determined by another study. * Patient/legal representative for whom it is impossible to provide informed information. * Pregnant or breast-feeding patient