Lead Sponsor

National Taiwan University Hospital

Age

40 - No limit years

Sex

ALL

Healthy Volunteers

Yes

•for PD patients:
•(1) a diagnosis of idiopathic PD by a neurologist expert in movement disorders (2) onset age \> 40 years old, (3) presence of gait disorders or freezing of gait (points on 3.10 in MDS-UPDRS\>=1 or points on item 3 in NFOG-Q \>0) (4) able to walk independently without an assistance device at least for 20 meters (5) without obvious action or postural tremor, according to the score of 3.15 and 3.16 (action and postural tremor of hands) in MDS-UPDRS
•for healthy elders:
•(1) without musculoskeletal of neurological diseases which may affect balance or walking performance (2) no medication that might influence their balance or cognition (3) MMSE\> 26 points.

•for PD patients:
•(1) with other neurological or musculoskeletal disease that might affect balance or walking (2) have a Mini-Mental State Examination (MMSE) \< 27 points (3) have a history of brain surgery (4) have to modulate their medication for duration of the experiment.