Postural problem is described with MCPAA (Measure of Postural Control in Sitting Position, created by B. GAGNON, physiotherapist in Quebec) : we look at pelvic obliquity, pelvic rotation, pelvic anteversion or retroversion, trunk slope and rotation, kyphotic or scoliotic posture, neck posture and legs posture. We evaluate if these deformities are soft, moderate or severe, and if they are relievable