tACS for Sensory Motor Recovery After Stroke

Inclusion/exclusion criteria for stroke subjects Inclusion criteria: 1. Age between 18\~75 years old 2. ≥ 6 months post stroke, medically stable; 3. Unilateral, single stroke (no restriction on type (ischemic or hemorrhagic) or volume (large or small) of stroke); 4. Visible finger flexor activation/movement 5. The ability to give consent Exclusion criteria: 1. Patients with visual deficit/neglect; hearing or cognitive impairment; 2. Patients that are currently adjusting tone alternating medications (e.g., baclofen), or 3. Patients received botulinum toxin injection to the arm/fingers \<4 months, or phenol injections \<2 years; 4. Patients with pacemaker, metal implants or supplemental oxygen; 5. Patients who have musculoskeletal disorders, including pain in the affected side 6. Women who are pregnant.