Anodal Transcranial Direct Current Stimulation Over the Contralesional Hemisphere on Motor Recovery in Subacute Stroke Patients

Upper limb recovery is not predicted by the initial severity of paralysis and the parameters reflecting the integrity of the corticospinal tract (e.g. motor evoked potential, fractional anisotropy in diffusion tensor imaging). Although the inhibition of the contralesional hemisphere is known to be beneficial for the upper limb recovery after stroke in previous studies, this is not proven in the severely paralyzed upper limb. And the studies using the noninvasive stimulation in subacute stroke is lack. In addition, the role of contralesional (unaffected) hemisphere is known to be playing the important role in severe stroke. In this randomized, double-blind, sham-controlled studies, the patients with subacute stroke (\<3 months after stroke onset), severe paralysis of the upper limb with poor prognosis (poor motor score and no response of motor evoked potential recorded in the extensor carpi radialis muscle) will be recruited. Interventional group will receive the 25 mins of anodal transcranial direct current stimulation (tDCS) over the contralesional premotor area plus 25 mins of robotic arm training per session for 10 sessions in 2 weeks. Control group will receive the same treatment except for sham tDCS instead of anodal tDCS over the contralesional premotor area. Functional outcome will be measured before and after the intervention (baseline, immediately after the intervention and 1 month after the intervention). Cortical activation pattern will be measured by the electroencephalography (EEG) at baseline and immediately after the intervention.