Efficacy of Mechano-Acoustic Vibration on Strength, Pain, and Function in Poststroke Rehabilitation: A Pilot Study

Background: Vibration therapy may be used to help cortical reorganization after stroke as it can cause different adaptive metabolic and mechanical effects. Objective: This study examined whether the application of mechano-acoustic vibration on upper limb muscles could induce changes in range of motion (ROM), function, pain, and grip strength in individuals with chronic stroke. Methods: Out of 52 individuals post stroke with upper limb spasticity who were eligible,16 received mechano-acoustic vibration therapy (ViSS device) 3 times weekly for 12 sessions. The frequency of vibration was set to 300 Hz for 30 minutes. The treated muscles were the extensor carpi radialis longus and brevis and triceps brachii during voluntary contraction. All participants were evaluated in both upper limbs before (T0) and at the end (T1) of treatment with a dynamometer (hand grip strength), Modified Ashworth Scale, QuickDASH, FIM score, Fugl-Meyer scale, Verbal Numerical Rating Scale of pain, and Jebsen-Taylor Hand Function Test. Results: After 4 weeks, hand grip power had improved and pain and spasticity had decreased. Improvements were recorded for all parameters and were considered statistically significant. Conclusions: Application of vibratory stimuli to a muscle can increase the motor-evoked potential recorded from the muscle, suggesting an enhancement of corticospinal excitability. Low amplitude, high-frequency vibration treatment (300 Hz) can significantly decrease tone and pain and improve strength in upper limb of hemiplegic individuals, when applied for 30 minutes, 3 times a week over 4 weeks.