Immediate Effect of Postural Muscle's Vibrations on Gait in Chronic Vascular Hemiplegia

Overview

Balance disorders are very common after strokes and often last for long periods of time. Their origin is multifactorial and their impact on the daily lives of patients are particularly important, especially on gait. The vibration technology for rehabilitation was already studied in static posture with force plats but their impact on gait have yet to be evaluated. This present study aims at investigating the effects of vibrations applied by an approved medical device to the posterior neck muscles and the gluteus medius - major actors of proprioception and posture mechanisms - on gait disorders in patients with hemiplegia during the chronic phase after stroke.

An inclusion medical exam will occur in order to explain the protocol to the patients, to receive their written informed consent and to check the inclusion and absence of non-inclusion criteria. The study visit will happen in a 2 weeks' time span at most after the inclusion exam. During the study visit, the patients will undergo: * A quantitative gait analysis with Gait Rite and Optitrack before any intervention; * Then, in a randomized order: * A vibration stimulation on a non-postural muscle (biceps brachii muscle) in order to get a control stimulation (or "sham") with a new gait analysis with Gait Rite and Optitrack during the stimulation, then 2 and 10 minutes after it stopped, * A vibration stimulation of the posterior neck muscles on the hemiplegic side, with a new gait analysis with Gait Rite and Optitrack during the stimulation, then 2 and 10 minutes after it stopped. The precise stimulation location will be located by the pressures centre deviation on a medio-lateral axis on a strength platform (this area can vary for a few centimetres from patient to patient), * In order to assess the secondary outcome aiming at defining the best stimulation location, a vibration stimulation of the gluteus medius on the hemiplegic side, with a new gait analysis with Gait Rite and Optitrack during the stimulation, then 2 and 10 minutes after it stopped. In the same way than for the neck muscles, the scouting of the precise location will be assessed facing the greater trochanter by the pressures centre deviation on a medio-lateral axis on a strength platform. The realisation of the entire protocol will last approximately 90 minutes. At the end of the test, an optoelectronic recording by Optitrack will be realised on a treadmill in order to highlight potential differences between the gait on the ground and trained gait at comfortable speed for 2 minutes maximum.