Influence of physiotherapeutic facilitation techniques on motor evoked potentials in centrally paretic hand extensor muscles.

In the rehabilitation of stroke patients, various facilitation techniques are applied to reduce weakness in centrally paretic muscles and to improve functional motor capacity. The present investigation compared the facilitatory effect of 5 different physiotherapeutic approaches onto the centrally paretic extensor carpi radialis muscle in 30 stroke patients classified into 3 groups according to the individual degree of paresis. In order to quantify the influence of the respective facilitation manoeuvre, single transcranial magnetic stimuli were applied before and during the application of cutaneous/proprioceptive stimuli, a weight bearing task, contraction of the affected and the non-affected extensor carpi radialis muscle and during proximal preinnervation on the affected side. All procedures, indeed, enhanced the frequency of occurrence of muscular response potentials and their amplitudes while diminishing their response latencies. The most prominent effects were observed when the muscle itself was voluntarily activated. A similarly strong facilitation was obtained in the most severely affected patients with cutaneous and proprioceptive stimuli, but such stimuli had inhibitory effects in the healthy control group. The present study illustrates the interaction of cortically evoked motor potentials with peripherally or centrally generated inputs, contributes to the understanding of the neurophysiological mechanisms underlying physiotherapeutic facilitation techniques and helps in providing rational criteria to decide about the most appropriate facilitation method.