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International audience; Introduction The asymmetry of support when walking, common after a stroke, is a known risk factor for falls. The objective of this study is to assess effects of muscle vibrations on various sites on correcting this asymmetry. Methods Twenty-one patients (61 ± 13 years) with hemiplegia (10 right, 11 left) chronic vascular (mean time post stroke 48 ± 44months) received vibratory stimulation transcutaneous 70 Hz at the posterior cervical lesion contralateral muscles (NMV), the gluteus medius lesion side (GMV) and the biceps contralateral lesion (sham). An analysis of the percentage of one-foot support measured by GAITRite was performed before, during, and 2 and 10 minutes after each stimulation. Results Before stimulation, supporting asymmetry is noted with a percentage of the push side hemiplegic averaged 31.5% (±6.0%, min = 20%, max = 37%). Under GMV we find that this increases to 35.0% (±5.9%, min = 28.8%, max = 41.2%) against 31.1% (±7.5%, min = 20%, max = 42%) in NMV and 32.0% (±6.9%, min = 28.6%, max = 39.4%) in the sham. 2 minutes, the effect persists for GMV stimulation with 35.5% (±9.0%, min = 35%, max = 42.4%) 4% improvement then disappears in 10 minutes. The results are more significant in left hemiplegia with 7% improvement for GMV (P < 0.005). There is a more moderate effect on the NMV with a post effect at 2 min (32.6%) and 10 min (32.2%). Discussion–conclusion Vibratory stimulations therefore seem to improve support asymmetric walking hemiplegic patients. Different kinetic effect is observed between the cervical stimulation and gluteus medius. These results seem to reflect a different pathophysiology between the gluteus medius and cervical postural muscles. These could act through a central mechanism of spatial cognition while the hip muscles have a more immediate effect proprioceptive device. These analyses were complemented by a 3D gait analysis in an attempt to better understand the mechanisms of adaptation. This is the first study concerned with the effectiveness of vibratory stimulation on dynamic balance

Introduction Muscle vibration can be used to improve the center of pressure (CoP) shift. Several muscle sites have been used for various diseases without that we know their respective interest. Objective To compare the effects and post-effects of neck muscle vibrations (NMV) and gluteus medius vibrations (GMV) on balance in healthy subjects Methods Thirteen healthy subjects, mean: 23 years, right handed were tested on posturography, closed eyes, in standing position. They received successively left NMV and right GMV in a randomized order. The variation of the deviation of CoP on the mediolateral plane was evaluated under vibration stimulation (5 min), at the end of the vibration and 5 minutes after. Results GMV induce a CoP movement to left side (9 responders) (mean: 5.21 mm; SD: 4.79; P = 0.003). At the end of the vibration, the effect remained significant (mean: 4.73, SD: 4.02; P = 0.001) and after 5 minutes, the subjects restored their initial balance (mean: 1.25, SD: 6.82; P = 0.33). For NMV, a movement toward left side was observed only in 5 subjects but this deviation seemed to be maintained at 5 min. The CoP deviation was not significant during (P = 1), immediately after (P = 0.72), and after 5 minutes of NMV (P = 0.89). Discussion GMV cause a lateral shift in 70% of the subjects of nearly 5 mm. The effect of NMV was lower and less constant (only 5 responders) but sustainable. This could be explained by a sensorimotor peripheral action for GMV while NMV would involve high level body representation in space.

Introduction Comparer l’effet et le post-effet de vibrations des muscles du cou (NMV) et de vibrations du gluteus medius (GMV) sur l’equilibre debout statique chez le sujet sain. Methode Treize sujets sains d’âge moyen 23 ans, droitiers, sont testes debout yeux fermes sur plate-forme de force pendant la vibration (duree 5 min), a l’arret et 5 minutes apres, au cours de 2 sessions successives NMV gauche ou GMV droite selon un ordre randomise. Le critere principal etait la variation du deplacement moyen du centre de Pression (CoP) sur l’axe mediolateral. Resultats Les GMV provoquent un deplacement du CoP vers le cote gauche chez 70 % des sujets (9 repondeurs) (moyenne ± SD = 5,2 ± 4,8 mm) ( p = 0,003). Immediatement apres, l’effet reste present (moyenne ± SD = 4,7 ± 4 mm) ( p = 0,001) et apres 5 minutes, les sujets retrouvent leur position anterieure (moyenne ± SD = 1,25 ± 6,8) ( p = 0,33). Pour la NMV, seulement 5 sujets avaient un deplacement vers le cote gauche, qui semblait se maintenir. La variation du CoP n’etait pas significative pendant ( p = 1), immediatement apres ( p = 0,72) et apres 5 minutes ( p = 0,89). Discussion–conclusion Les GMV provoquent un deplacement chez 70 % des sujets en moyenne d’un peu plus de 5 mm. L’effet des NMV est plus variable d’un sujet a l’autre. Ceci pourrait etre explique par une action sensorimotrice peripherique majoritaire de la vibration du muscle GM alors que la NMV mettrait en jeu des circuits plus haut situes au niveau de la representation du corps dans l’espace.

Introduction L’asymetrie posturale retrouvee en position debout apres un AVC est bien connue. Elle est due en partie a un deficit sensorimoteur mais semblerait aussi liee a un trouble de la representation du corps dans l’espace, dont la perturbation de la perception de l’axe egocentrique. L’objectif de cette recherche est de determiner si l’asymetrie posturale des patients cerebroleses evalues en position debout par la Plateforme (PF) et en position assise par l’echelle Scale Contraversive Pushing (SCP) est correlee a une mauvaise apprehension du referentiel egocentrique, evalue par le test de l’Axe longitudinal (LBA) et le test Droit devant (DD). Materiels et methodes Trente-deux patients et 31 sujets sains volontaires ont participe a l’etude. La relation entre l’axe egocentrique et l’asymetrie posturale a ete testee par un test de correlation partielle avec la force musculaire et la sensibilite comme covariables. Resultats Les resultats montrent un lien significatif entre le SCP et le test DD ( r = 0,49, p = 0,01) chez les patients ne tenant pas debout mais pas de lien significatif entre le SCP et le test LBA ( r = −0,31, p = 0,14) ; ainsi qu’un lien significatif entre la PF et le test LBA ( r = 0,42, p = 0,03) dans le sous-groupe de patients tenant debout mais pas entre la PF et le test DD ( r = −0,12, p = 0,51). Discussion–conclusion Ces tests LBA et DD pourraient etre utilises en clinique dans l’evaluation des facteurs de trouble de l’equilibre du patient et permettre de proposer une reeducation ciblee.