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

Objective The objective of this preliminary study is to test the long-lasting effects of repetitive neck muscle vibration (rNMV) on postural disturbances and on spatial frame reference in chronic patients. Material/patients and methods Twenty chronic stroke patients (mean age 61.4y ± 11, mean delay since stroke 5.5y ± 3), 10 right (RDB) and 10 left (LDB) brain damage, having gained the capacity to stand for more than 30 s were included. They underwent 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 twice before (D-15, D0) and ultimately at the end of the vibrations (D + 15, D + 22, D + 45). Results In the posttest, 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) on the contrary, no effect was observed in the LBD group. In addition, no significant modification was found on the spatial frame in both RBD and LBD. A significant improvement was found for the Motricity and Time Up and Go at D + 22 in the RBD group whereas no modifications were found in the LBD. Discussion – conclusion rNMV causes a reduction of postural asymmetry in the RBD group independently of the space representation improvement. Likewise, rNMV can modify the postural asymmetry of patients at distance from their stroke but this result was not maintained at D + 45.