Unilateral Vibration Stimulation in Patients With Post-stroke Spasticity Suppresses Muscle Tonus in the Contralateral Homologous Muscles

OBJECTIVE: This study aimed to examine whether unilateral vibration stimulation can reduce spasticity during the stimulation period in post-stroke patients. METHODS: Ten post-stroke patients with increased muscle tone in the flexor carpi radialis (FCR) participated. Vibration stimulation at 80 Hz was applied to the paretic-side FCR. The H-reflex and muscle stiffness were assessed before, during, and immediately after stimulation. Changes in H-reflex parameters were analyzed alongside muscle stiffness using the Wilcoxon signed-rank test. RESULTS: H-reflex measurements showed a temporary reduction in spasticity during stimulation. However, no significant change was observed in muscle stiffness. CONCLUSION: Unilateral vibration stimulation may offer immediate neurophysiological suppression of spasticity during application, although it does not appear to affect muscle stiffness in the short term. These findings suggest potential for use as a complementary intervention in stroke rehabilitation.