This research is being done to find out if brain stimulation combined with a rehabilitation therapy improves arm weakness as a result of having a stroke. The stimulation technique is called transcranial direct current stimulation (tDCS). The treatment uses direct electrical currents to stimulate specific parts of the brain. The rehabilitation therapy is called "modified Constraint Induced Movement Therapy" (mCIMT). During this rehabilitation therapy study participants will wear a mitt on the hand of the arm that was not affected by their stroke. It is designed to restrain the use of the unaffected arm, while performing therapy with impaired one.
It is not known if brain stimulation combined with rehabilitation therapy will improve arm weakness. Study participants will receive rehabilitation therapy while on this study. Study participants may or may not receive the brain stimulation therapy.

Stroke survivors with arm paresis because of stroke use their "good" arm for daily activities, but in doing so may be self-limiting their own recovery of the "bad" arm. Traditional models of stroke rehabilitation fail to fully engage the survivor and care partner(s) in actively planning post-discharge habits that improve their capacity to live well over their entire lives. This study will test a cutting-edge in-person therapy + online training program designed to progressively transfer the responsibility of driving post-stroke recovery from the therapist to the survivor.