Combined Transcranial Direct Current Stimulation and Robot-Assisted Arm Training in Subacute Stroke Patients

Abstract

Background. No rehabilitation intervention has effectively improved functional use of the arm and hand in patients with severe upper limb paresis after stroke. Pilot studies suggest the potential for transcranial direct current stimulation and bilateral robotic training to enhance gains. Objective. In a double-blind, randomized trial the combination of these interventions was tested. Methods. This study randomized 96 patients with an ischemic supratentorial lesion of 3 to 8 weeks’ duration with severe impairment of motor control with a Fugl-Meyer score (FMS) for the upper limb <18 into 3 groups. For 6 weeks, group A received anodal stimulation of the lesioned hemisphere, group B received cathodal stimulation of the nonlesioned side for 20 minutes at 2.0 mA, and group C received sham stimulation. The electrodes were placed over the hand area and above the contralateral orbit. Contemporaneously, the subjects practiced 400 repetitions each of 2 different bilateral movements on a robotic assistive device. Results. The groups were matched at onset. The FMS improved in all patients at 6 weeks (P < .001). No between-group differences were found; initial versus finish FMS scores were 7.8 ± 3.8 versus 19.1 ± 14.4 in group A, 7.9 ± 3.4 versus 18.8 ± 10.5 in group B, and 8.2 ± 4.4 versus 19.2 ± 15.0 in group C. No significant changes between groups were present at 3 months. Conclusions. Neither anodal nor cathodal transcranial direct current stimulation enhanced the effect of bilateral arm training in this exploratory trial of patients with cortical involvement and severe weakness. Unilateral hand training and upregulation of the nonlesioned hemisphere might also be tried in this population.