The long-lasting effects of repetitive neck muscle vibration on postural disturbances in standing position in chronic patients

Abstract

Introduction Asymmetrical postural behaviours are frequent and related to poor equilibrium after a stroke. Proprioceptive neck vibration could correct the postural asymmetry through a sensory recalibration but the long lasting effect has not yet tested. Objective To test the long-lasting effects of repetitive neck muscle vibration (rNMV) on postural disturbances and on spatial frame reference in chronic patients. Methods Twenty chronic stroke patients (mean age: 61.4 y11, mean delay since stroke: 5.5y3), 10 right (RDB) and 10 left (LDB) brain damage, underwent a program of 10 vibrations of 10 min sessions during two weeks–the evaluation of 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 before (D−15, D0) and at the end of the vibrations (D + 15, D + 22, D + 45). Results In the post-test, a significant reduction in WBA was established in the RBD (P = 0.009) and was maintained at D + 15 (P = 0.01) and D + 22 (P = 0.05), no effect was observed in the LBD. In addition, no significant modification was found on the spatial frame in both group. A significant improvement was found for the motricity and time up and go in the RBD. Discussion rNMV causes a reduction of postural asymmetry in the RBD group independently of the space representation improvement. Likewise, rNMV can modify the postural asymmetry in chronic patients but this result was not maintained at D + 45.