Could a gentle zap to the nerves help stroke survivors move better?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * History of unilateral supratentorial ischemic, intracerebral hemorrhagic, subarachnoid hemorrhagic, or a heterogeneous lesion stroke that occurred at least 6 months but not more than 15 years prior to enrollment. * Age \>30 years and \<85 years. * Fugl-Meyer Assessment, Upper Limb (FMA-UE) baseline score of 10 to 56 (inclusive of 10 and 56). * Ability to communicate, understand, and provide appropriate consent. Subjects should be able to follow two-step commands. * Right- or left-sided weakness of the upper extremity. Exclusion Criteria * Participant with any implanted metallic device at or near the stimulation sites (forehead and ears). * Participant with an implanted or active stimulator (ex. Deep brain stimulator, pacemaker, vagus nerve stimulator, defibrillator) * Participant skin in the stimulation area has open wounds, skin eruptions, swollen, infected, or inflamed areas, or skin abnormalities that could be cancerous * Advanced cardiac, pulmonary, liver, kidney dysfunction or blood system disease * Participant has a fever or shows clinical signs concerning for an infectious disease * Other neurologic or musculoskeletal diseases that could interfere with the assessments of this study * Low heart rate (\<60 bpm) from a cardiac conduction block or related etiology * Participant has a history of trigeminal neuralgia * Participant has a history of Bell's Palsy * History of cranial nerve neuropathy (including facial nerve injury), carotid surgery, vagotomy, or other surgical intervention on the vagus nerve * History of recurrent syncopal events * Known or newly-discovered aneurysm or arteriovenous malformation * Patients who have any terminal illness such that the patient would not be expected to survive more than 90 days * Botox injections 12 weeks prior to or during therapy * Participants who have had a craniectomy: * Without replacement of bone flap * With bone flap replaced \< 6 months prior to initiation of study activities