Optimal Targeted High-definition Transcranial Direct Current Stimulation for Reducing Post-stroke Upper Limb Motor Impairments

Non-invasive, non-pharmaceutical technologies that augment routine clinical practice for brain diseases and manage chronic symptoms have advanced rapidly over the past two decades. Among these, non-invasive brain stimulation such as transcranial direct current stimulation (tDCS) promotes neuroplasticity in injured brains, with fewer side effects and risks than invasive, implanted approaches such as deep-brain stimulation. Stimulating the brain can improve its function and help with recovery after a stroke. It has been a challenge to do this non-invasively. This is because the brain is reshaped after a stroke, and thus, it is difficult to find the right places to stimulate from the outside. In previous research, investigators found that optimal type and target of tDCS varied among subjects. The goal of this pilot trial is to test the feasibility of combining individually optimized, targeted high-definition tDCS (THD-tDCS) with rehabilitation therapy. Investigators will include 16 chronic stroke subjects with their optimal stimulation setup, obtained from their previous research. The participants will be computer-randomized into two equal-sized groups to receive either optimal THD-tDCS or sham stimulation, together with rehabilitation therapy (modified constraint-induced movement therapy, mCIMT) for five sessions over two weeks. Outcome measures will be collected at the baseline and right after the final intervention session. The primary outcome measure will be the change in the FM-UE score from baseline to immediately post the final intervention to assess the immediate effect of the intervention on upper extremity motor impairment. The secondary outcome measure will be the Wolf Motor Function Test time score to evaluate the immediate effect on functional motor performance.