Postural-suprapostural task is defined as postural control takes place while at least one other concurrent task is being performed. In a postural-suprapostural task, appropriate prioritization of is necessary to achieve task goals and maintain postural stability. Therefore, regarding to impose task prioritization in a postural-suprapostural task, the optimal task-priority strategy for PD patients is still an issue of debate. With the uses of EEG, EMG and behavioral measures, the purpose of this project is to investigate the differences in performance quality and intrinsic neural mechanisms of a postural-suprapostural task for PD patients, by adopting posture-focus and suprapostural-focus strategies during standing and walking. The present project is expected to have significant contributions not only to gain a better insight to neural correlates of concurrent postural and suprapostural tasks with different task prioritization under standing and walking, but to optimize treatment strategy for PD patients with balance or dual-tasking disturbances.

Postural-suprapostural task is defined as postural control takes place while at least one other concurrent task is being performed. In a postural-suprapostural task, appropriate prioritization of is necessary to achieve task goals and maintain postural stability. Some studies support that a "posture-first" strategy is favored by patients with Parkinson disease (PD) in order to secure stance stability, but this comes at the cost of reduced suprapostural performance. In addition, overemphasizing on postural task might deteriorate automatic control of posture resulting in increased postural instability, and the best task-priority strategy might vary with balance ability of PD patients. Therefore, regarding to impose task prioritization in a postural-suprapostural task, the optimal task-priority strategy for PD patients is still an issue of debate. With the uses of EEG, EMG and behavioral measures, the purpose of this 2-year research project is to investigate the differences in performance quality and intrinsic neural mechanisms of a postural-suprapostural task for PD patients, by adopting posture-focus and suprapostural-focus strategies during standing and walking. In the first year, we will characterize task prioritization effect on reciprocity of a postural-suprapostural task, with a special focus on modulation of brain and muscle activity patterns in standing posture for early stage (modified H & Y: 1, 1.5 and 2) and moderate stage (modified H & Y: 2.5 and 3) PD patients. In the second year, the appropriate task prioritization, walking automaticity and power/connectivity of brain areas will be investigated in walking for PD patients with/without freezing of gait. The present project is expected to have significant contributions not only to gain a better insight to neural correlates of concurrent postural and suprapostural tasks with different task prioritization under standing and walking, but to optimize treatment strategy for PD patients with balance or dual-tasking disturbances.

inclusion criteria:

1. patients with Parkinson's Disease in H&Y stage from stage 1 to stage 3
2. without other neurological disease with balance impairment
3. can stand and walk without aids for at least 30 seconds

exclusion criteria:

1. Mini-Mental State Examination > 27
2. Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) < 10
3. Hamilton Depression Rating Scale (HAM-D) < 17
4. pregnancy