Effects of anodal transcranial direct current stimulation over the contralesional hemisphere on motor recovery in subacute stroke patients with severe upper extremity hemiparesis: Study protocol for a randomized controlled trial

INTRODUCTION: Upper extremity motor impairment is one of the major sequelae of stroke, resulting in limitations of activities of daily living. Recently, contralesional cortical activation has been reported to be important for motor recovery in stroke patients with severe upper extremity hemiparesis due to the extensive corticospinal tract involvement. We therefore designed this study to investigate the effects of contralesional anodal transcranial direct current stimulation (tDCS), which induces cortical activation, in stroke patients with severe upper extremity motor impairment. METHODS AND ANALYSIS: We will recruit patients with subacute stroke (<3 months after onset) with unilateral upper extremity weakness who meet the following criteria: Shoulder Abduction and Finger Extension (SAFE) score below 8, Fugl-Meyer Assessment for upper extremity (FMA-UE) score ≤25, and absent motor evoked potential (MEP) response on the affected extensor carpi radialis muscle. Subjects will be randomly allocated to either the intervention (n = 18) or the control group (n = 18). The intervention group will undergo 10 sessions of robotic arm rehabilitation with simultaneous anodal tDCS over the contralesional premotor area, whereas the control group will receive sham tDCS during the same sessions. One daily session consists of 25 minutes. The primary outcome measure of this study is the Fugl-Meyer Assessment score of the upper extremity; the secondary outcome measures are the Korean version of the Modified Barthel Index, the Brunnstrom stage of the affected arm and hand, the Box and Block Test, the Modified Ashworth Scale, the Manual Muscle Power Test, and the patient's encephalographic laterality index. DISCUSSION: Findings of this study will help to establish an individualized tDCS protocol according to the stroke severity and to find out the EEG parameters to predict the better recovery in subacute stroke patients with severe upper extremity hemiparesis. ETHICS AND DISSEMINATION: The study was approved by the Seoul National University Bundang Hospital Institutional Review Board (IRB No. B-1806-475-006) and will be carried out in accordance with the approved guidelines. The results of the trial will be submitted for publication in a peer-reviewed journal.