- 學位論文
以分形布朗運動研究屈肘及前臂內旋之協同作用
Synergic Co-activation in Elbow Flexion and Forearm Pronation via Fractional Brownian Motion
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摘要
人類在自由意志下的肢體運動，其主動肌 (agonist) 與拮抗肌 (antagonist) 存有共同作用情形 (co-activation)。近期的研究中指出：這樣的作用情形，可以區分為肌肉群間互相協同作用 (synergic) 或非互相協同作用 (dyssynergic) 的情形。因此，本研究的目的有二，一則是要發展一種可以擷取肌電訊號 (EMG) 的強度與頻率訊息的方法，另一則則是要研究正常人在主動 (自由意志下) 肘屈與前臂內旋時，參與的肌肉群是否處於相互共濟的協同作用，而對於橈神經癱瘓 (radial nerve palsy) 的病人，在主動前臂內旋運動時，參與的肌肉處於非共濟的共同作用。在肘彎曲的實驗中，有六位正常人參與了實驗；而在前臂內旋的實驗中，有十一位正常人和四位右手橈神經癱瘓的病人參與了實驗。實驗結果顯示：正常人的肌電訊號在休息與在被動 (非自由意志) 下的肘屈與前臂內旋，其碎形維度 (fractal dimension) 與頻率變化上並無顯著的不同。但是，在主動的情形下這兩種肌電訊號在運動時都顯現出頻率上的同步性 (synchronization) 與強度的持續性 (persistence) 的特質。因此，這樣結果告訴我們：在自由意志下參與這兩種運動的肌肉群處於相互共濟的協同作用。另一方面，正常人在肌肉休息時與在主動肘彎曲和前臂內旋時的碎形維度平均值亦有顯著的不同。然而，對於病患而言，他們的肌電訊號雖仍有爆發性的活動，但是卻缺乏頻率的同步性與肌電訊號強度的持續性。最後，為了說明我們所提出的方法的優點，我們比較了主成分析的方法 (principal component analysis) 和去擾動的分析方法 (detrended fluctuation analysis)。一般相信，我們所提出的研究方法有潛力成為評估神經肌肉動態疾病 (dynamical diseases) 的重要指標。
並列摘要
Co-activations of agonist and antagonist muscles are believed to be present in voluntary limb movement. Recent studies indicate that such co-activations are either synergic or dyssynergic. The aims of this study are (1) develop a novel method that can extract both the intensity and frequency information from the recordings of the surface electromyograms (EMGs) of involved muscles, and (2) to investigate if the involved muscles will be under synergic co-activation during voluntary elbow flexion and voluntary forearm pronation for normal subjects and dyssynegic co-activation for patients with radial nerve palsy. We examined six healthy subjects for the experiment of elbow flexion and eleven healthy subjects and four patients with right-arm radial nerve palsy for the experiment of forearm pronation. Experimental results of the healthy group indicated that the surface EMGs of all muscles had no statistically significant changes in fractal dimensions (FDs) and spectral frequencies during passive elbow flexion and forearm pronation. Yet, during the voluntary elbow flexion and the voluntary forearm pronation, the surface EMGs of all muscle groups were temporally synchronized in frequencies with persistent intensities. Hence, all involved muscle groups were in synergic co-activation. Statistical results of the group mean values of FDs during rest versus elbow flexion or forearm pronation also revealed significant difference with P < 0.01 for healthy subjects. As to the group of patients in the experiment of forearm pronation, their EMGs could still have bursting activities, but the synchronized significant frequencies might be lacking or the intensities as indicated from their FDs would not be persistent. Finally, in order to illustrate the advantages of our method, we have compared it with the principal component analysis (PCA) and the detrended fluctuation analysis (DFA). It is believed that this proposed method will have the potential to be a biomarker for evaluating dynamical disease in neuromuscular disorders.
參考文獻
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