Effects of repetitive neck muscle vibrations on postural disturbances in standing position in chronic patients

Abstract

Asymmetrical postural behaviors are frequent and related to poor equilibrium after a stroke. Proprioceptive neck vibration corrects in the short term the postural asymmetry probably through a sensory recalibration, but the effects of repetitive has yet to be tested. The objective was to test the effects of repetitive neck muscle vibration (rNMV) on postural disturbances and on spatial frame reference in right (RBD) and left (LBD) brain damage patients. Thirty-two chronic stroke patients (mean age 60.9 ± 10 y and mean delay after stroke 4.9 ± 4 years), 16 RBD and 16 LBD, underwent a program of 10 sessions of vibrations (10 min) during a period of two weeks. Postural asymmetry on force platform (Weight Body Asymmetry WBA), spatial frames (Subjective Straight Ahead SSA, Longitudinal Body Axis LBA, Subjective Visual Vertical SVV) and clinical assessment (Motricity Index, Sensibility, Spasticity, Berg Balance Scale, Time Up and Go) were ascertained at the end of the vibrations (D + 15) and at D + 22, D + 45. In the post-test, the results were depending of the side of the lesion with a significant reduction in WBA in the RBD ( P = 0.0001), whereas no effect was observed in the LBD. No significant modification was found on the spatial frame in both groups. A significant improvement was found for the Motricity, TUG and BBS in the both groups at the end and at distance. rNMV causes a reduction of postural asymmetry only in the RBD patients. These results suggest that rNMV could be effective on sustainable disorders of balance of spatial cognition disorders. Further, this result was not maintained at distance.