Inclusion Criteria1. diagnosis with stroke through computed tomography or magnetic resonance imaging, more than six months ago.
2. determination not to have cognitive disability, based on the score(>24 point) of mini mental state examination-Korea version.
3. determination not to have visual abnormalities including the unilateral neglect through the motor-free visual perception test(MVPT)
4. ability to independently gait longer than 10m in the room and to keep standing up without help.
Exclusion Criteria1. surgery in the last three months
2. participating any other research