Inclusion Criteria- First episode of stroke in cortical regions
- Time since stroke more than 6 months
- Initial motor part of UE of FMA score ranging from 24 to 52, indicating moderate to mild movement impairment
- No severe spasticity in any joints of the affected arm (Modified Ashworth Scale ≤ 2)
- No serious cognitive impairment (i.e., Mini Mental State Exam score≧ 24)
- Willing to sign the informed consent form.
Exclusion Criteria- Aphasia that might interfere with understanding instructions
- Visual/attention impairments that might interfere with the seeing of mirror illusion, including hemineglect/hemianopsia
- Major health problems or poor physical conditions that might limit participation
- Currently participation in any other research
- Previous brain neurosurgery
- Metallic implants within the brain.