Oral Communication

Effects of vibration on the bearing asymmetry walking in chronic stroke patients


a Service de médecine physique et de réadaptation, CHU Pontchaillou, b Laboratoire Mouvement, Sport, Santé, avenue Robert Schuman, 35270 Bruz, France, c Service MPR neurologique, CMRRF Kerpape, 56275 Ploemeur,France, d Service de médecine physique et de réadaptation, CHU Pontchaillou, 2, rue Henri-Leguilloux, 35033 Rennes cedex, France

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: 21 patients (61+/- 13 years) with hemiplegia (10 right, 11 left) chronic vascular (mean time post stroke 48+/- 44months) received vibratory stimulation transcutaneous 70Hz 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.

Keywords : stroke, balance, gait, proprioception, vibrations