Bilateral High-Definition Transcranial Direct Current Stimulation for Upper Extremity Rehabilitation in Stroke.

Previous research shows that both anodal and cathodal high-definition transcranial direct current stimulation (HD-tDCS) may improve function of the upper extremity post stroke. However, most research has focused on the effects separately, therefore the purpose of this study was to determine the effects of performing simultaneous anodal-cathodal HD-tDCS. Five stroke participants received the stimulations in four visits with a two-week washout period: 1) anodal HD-tDCS to the ipsilesional primary motor cortex, 2) cathodal HD-tDCS to the contralesional dorsal premotor cortex, 3) bilateral anodal-cathodal HD-tDCS, and 4) sham. Active stimulation (anodal, cathodal, and bilateral) increased Fugl-Meyer upper extremity scores and decreased latency of ipsilesional M1-induced MEP. These results suggest that HD-tDCS could improve motor function of the upper extremity post-stroke, however, bilateral stimulation may not have an increased effect compared to anodal and cathodal HD-tDCS separately. This early phase study improves our understanding of neural circuitry and plasticity post stroke and HD-tDCS methods for improving function of the impaired arm post-stroke.