Vibration-induced effects in stroke patients with spastic hemiparesis--a pilot study.

BACKGROUND

Spasticity manifesting as a dysbalance between extensor and flexor muscles may contribute to an impaired hand function. We studied clinical (n=10 patients) and electrophysiological (n=9 patients) changes produced by vibration of forearm extensor muscles (FEM) in chronic stroke patients with spastic hemiparesis.

METHODS

In Exp. 1, the Box and Block Test (BBT) was applied to test dexterity before and after 5 minutes of FEM vibration. In Exp. 2, transcranial magnetic stimulation was used to study the cortical silent period (CSP) before and during FEM vibration. Recordings were taken from the antagonistic flexor carpi radialis muscle.

RESULTS

After vibration, performance of the BBT was improved by 20%. The effect persisted for at least 10-15 minutes. Vibration induced a prolongation of the CSP. This effect occurred in the affected and non-affected side to a similar degree. The magnitude of performance changes and CSP changes was not correlated.

CONCLUSIONS

FEM vibration enhances inhibitory neuronal circuits targeting the antagonistic forearm flexor muscles and is associated with an improved dexterity in the spastic arm. It might become a supporting tool in the motor recovery of spastic hemiparesis.