Eligibility CriteriaInclusion criteria:
1. at chronic stage (6 months after the onset of stroke) with a pure unilateral motor paresis after a stroke (ischemic or hemorrhagic);
2. sufficient cognition to follow simple instructions as well as understand the content and purpose of the study;
3. able to sit up for 45 minutes (with or without assistance), and have muscle strength grade from 1 to 3 in the abductor pollicis brevis and extensor digitorum in the affected side.
1. Patients with severe dysphasia (either expressive or comprehensive) with inadequate communication;
2. any additional medical or psychological condition affecting their ability to comply with the study protocol;
3. history of other neurological disease, psychiatric disorder, including alcoholism and substance abuse.