Vibratory stimulation and not action observation or mirror therapy reduces paralyzed hand spasticity in chronic stroke survivors

Objective Post-stroke spasticity prevalence increases with time from stroke onset, and negatively impacts the patient’s quality of life. Vibratory stimulation (VS) to the spastic muscles can reduce spasticity, whereas action observation (AO) and mirror therapy (MT) are reported to be less effective for spasticity reduction. However, these effects have not been compared within the same individuals. Therefore, this study compared the spasticity-reducing effects of VS, AO, and MT. Methods Independent groups of 13 patients with chronic stroke participated in the study. In Experiment 1, the participants underwent VS, AO, and combined VS+AO on separate days. In Experiment 2, different participants received VS, MT, and VS+MT. Spasticity was assessed using the Modified Ashworth Scale (MAS) before and after the interventions. Results In Experiment 1, VS significantly reduced MAS scores but not AO, and AO did not enhance the VS effect in combined therapy. In Experiment 2, VS significantly reduced the MAS scores, but not MT, and MT did not enhance the VS effect in combined therapy. Conclusion Spastic muscle VS reduced spasticity in chronically paralyzed hands; however, AO and MT did not enhance the VS effect. VS alone may be a more effective treatment for spasticity in patients with chronic stroke.