Therapeutic effectiveness and limitations of noninvasive brain stimulation in hemiplegic patients

Noninvasive brain stimulation techniques such as rTMS and transcranial direct current stimulation (tDCS) have emerged as a promising tool for enhancing recovery of hemiplegia following stroke. In patients with a unilateral supratentorial lesion, up-regulation of excitability of the affected hemisphere by high-frequency rTMS or anodal tDCS over the affected motor area, or down-regulation of the unaffected motor area by low frequency rTMS or cathodal tDCS, have been reported to improve motor function in a hemiplegic hand. In the literature concerning the effect of rTMS or tDCS on motor function of the affected hand in chronic hemiplegic patients, these interventions improved reaction time, movement speed, and manual performance rather than voluntary hand function evaluated with clinical scales. We presented the effectiveness of a unique method for treating hemiplegic hand in chronic stroke patients, i. e., TMS synchronized with maximal effort at a target hand movement (effort-associated TMS). Further studies such as large randomized controlled trials with more TMS sessions and longer follow-up periods would further clarify the effectiveness and limitations of effort-associated TMS.