Anti-spastic effects of the direct application of vibratory stimuli to the spastic muscles of hemiplegic limbs in post-stroke patients: A proof-of-principle study

OBJECTIVE: To investigate whether the direct application of vibratory stimuli inhibits spasticity in the hemiplegic upper limbs of post-stroke patients. DESIGN: A randomized controlled study. SUBJECTS: Thirty-six post-stroke patients. METHODS: Patients were randomly allocated to the "Rest group", "Stretch group", or "Direct application of vibratory stimuli group". After relaxing in a supine posture for 30 min, subjects received the interventions for 5 min. The Modified Ashworth Scale scores and F-wave parameters were recorded before, immediately after and 30 min after each intervention. RESULTS: The Rest group showed no significant changes in F-wave parameters and Modified Ashworth Scale scores. The Stretch group showed a tendency to decrease in F-wave amplitude and F/M ratio immediately after the intervention, but not 30 min later. The Direct application of vibratory stimuli group showed significant improvements in F-wave parameters and Modified Ashworth Scale scores immediately after the intervention, which remained 30 minutes later. The changes in F-wave parameters and Modified Ashworth Scale scores observed in the Direct application of vibratory stimuli group significantly differed from those in the Rest group and the Stretch group. CONCLUSION: The direct application of vibratory stimuli has anti-spastic effects in the hemiplegic upper limbs of post-stroke patients.