目的：本研究是比較巴金森氏症患者與正常人肌肉反應方向區辨性之差異。方法：受試者為6名巴金森氏症患者及6名健康成人為對照組。使用電腦平衡測定儀及其所附之八頻道體表肌電圖系統(SMART Balance Master system with 8 channel surface EMG system)測量姿勢反應，力板以50°/s的速度突然向上或向下旋轉4°，造成足踝蹠屈或背屈各連續10次。紀錄左側經前肌、腓腸肌、膕旁肌、股四頭肌之肌電訊號。結果：除膕旁肌外(p=0.082)，兩組之其它肌肉反應起始時間皆受旋轉方向的影響(p<0.05)。遠端與近端肌反應起始之收縮時序的時間差(time lag)，巴金森氏組大於對照組，出現較多時序反轉現象，但沒有統計學上顯著差異。腓腸肌振幅受到組別與干擾方向之交互作用(p=0.006)。結論：巴金森氏症患者在受到不同方向旋轉干擾時，肌肉反應會出現與正常人類似具方向區辨性的姿勢反應，但有較多時序反轉、反應起始時間變快和反應振幅增大等姿勢不穩現象。

Purpose: The aim of the study vas to compare the direction-specific postural muscle responses between patients with Parkinson's disease (PD) and healthy control subjects. Methods: Six patients with PD and six age-matched healthy subjects were recruited in this study. Postural responses were tested using the Smart Balance Master system with an eight-channel electromyography (EMG). The stimuli were 4° upward or downward platform tilts at 50°/s. Ten consecutive trials were given for each direction of platform tilts. EMG activities of the tibialis anterior, hamstrings, gastrocnemius and quadriceps in the left leg were recorded. Results: Significant effects of perturbation direction on the onset latencies were found for muscles in both groups (p<0.05) with an exception for the hamstrings muscle (p=0.082). The PD group showed a trend towards increasing the time lag in onset latencies between proximal and distal leg muscles, compared to the control group. The temporal reversals were also observed more frequently in the PD group than the control group. There was a significant group by direction interaction effect on the amplitude of the gastrocnemius muscle activity (p=0.006). Conclusions: The results showed that PD patients retain direction-specific muscle responses to platform rotation perturbations However, more temporal reversals and a trend toward increased onset latency and increased muscle response amplitude were observed in the PD group.