功能性肌電生物回饋儀輔助之肌肉訓練對慢性腦中風患者大腦皮質神經興奮性與下肢 動作功能的療效研究

Effects of Functional Electromyographic Biofeedback Muscle Training on Cortical Excitability and Lower Limb Motor Function in Chronic Stroke

蔡佩玲(Peih-Ling Tsaih)

指導教授 ： 胡名霞

國立臺灣大學/醫學院/物理治療學研究所/博士(2014年)

https://doi.org/10.6342/NTU.2014.02109

摘要

研究背景與目的：力量(force)的產生與控制是順利進行日常生活活動非常重要的神經肌肉控制機制。脛前肌(tibialis anterior)出力控制不良被認為是造成腦中風患者踝關節背屈障礙並影響平衡與行走功能的重要因素。肌電生物回饋儀(EMG biofeedback, 簡稱EMGBFB)則是最常被建議使用的動作治療輔助工具，然而其對動作功能的療效目前仍無定論。依據動作學習理論(motor learning theory)的闡述，動作技巧的學習並非只是重覆的練習相同動作，除了任務導向(task-oriented approach)概念、主動學習與回饋的操弄之外，加入練習的變異性才能習得調整動作的能力及解決動作問題的方法。因此，發展以動作學習理論為基礎的功能性肌電生物回饋儀訓練以改善腦中風患者的動作功能，是臨床上非常重要的議題。近代神經科學研究顯示，動作訓練伴隨的大腦重組和神經塑性是腦中風患者動作功能恢復的基礎。利用穿顱磁刺激(transcranial magnetic stimulation，簡稱TMS)來偵測大腦皮質變化，可以了解動作訓練對大腦皮質重組與神經再塑的影響，有助於了解動作訓練的神經機制進而有利於設計能誘發目標腦區神經再塑的訓練方式，並進一步尋找有效的治療模式與參數。本論文的研究的目的為(一)以綜合分析(meta-analysis)方式探討近代肌電生物回饋儀輔助訓練對慢性腦中風患者動作功能的療效；(二)以功能性肌電生物回饋儀輔助脛前肌肌肉訓練，探討固定與變異練習模式對慢性腦中風患者脛前肌肌力、動態平衡、下肢動作功能以及穿顱磁刺激誘發之脛前肌神經興奮性的療效；(三)探討訓練後脛前肌神經興奮性變化與動作功能改善的相關性；(四)探討高、低劑量肌電生物回饋儀輔助脛前肌肌肉訓練的療效。研究設計與方法：首先由兩位評論者搜尋至2011年10 月的隨機分組控制研究進行綜合分析，包含自MEDLINE, PubMed, PEDro, CEPS, CINAHL,及Cochrane等電子資料庫。再來進行前驅研究確認功能性肌電生物回饋儀輔助脛前肌肌肉訓練的可行性，三位受試者被分派為固定練習組、變練習和對照組。每位受試者均接受每次約40分鐘共十八次的訓練(每週三次、共六週)；固定練習和變異練習組在功能性活動下(站立、登階、重心前後位移、踏步及行走)強調消褪式回饋的肌電生物回饋儀輔助之脛前肌肌肉訓練，對照組為上肢運動訓練。固定練習組以肌電生物回饋儀顯示之脛前肌最大收縮肌電量為訓練目標。變異練習組以肌電生物回饋儀顯示之脛前肌最大收縮肌電量的25%、50%、75%及100%為隨機訓練目標。所有受試者皆維持原有的復健治療及活動，內容包含跑步機行走訓練。每位受試者均接受訓練前、訓練後、訓練後二週和六週共四次評估。評估項目包括脛前肌最大肌力、電腦動態平衡儀之動態平衡測驗、行走速度、計時起走測驗(Timed Up and Go Test, 簡稱TUGT)、六分鐘行走測驗(Six-minute Walking test, 簡稱6MWT)與穿顱磁刺激誘發之神經興奮性，包括脛前肌的運動閾值(motor threshold, 簡稱MT)與運動誘發電位振幅(MEP amplitude)等。接著進一步進行單盲設計之隨機分組控制實驗，研究方法如前驅研究所述。共有三十三位腦中風患者被隨機分配於三組：固定練習組(13位)、變異練習(11位)和對照組(9位)。再者分析訓練前與訓練後脛前肌肌力與脛前肌運動閾值變化的相關性。最後探討高、低劑量的肌電生物回饋儀輔助脛前肌肌肉訓練的療效研究，共四十位慢性腦中風患者依訓練劑量被分類於三組，高劑量 (13人，共練習1440下，每次練習80下次共18次)、低劑量(12人，共練習240下，每次練習20下次共12次)及對照組(15人，上肢運動訓練)。其中低劑量組受試者資料取自本人之碩士論文資，高劑量組受試者資料取自本研究的固定練習組，對照組為兩個研究的對照組受試者。每組運動訓練時間均為期4到6周、每次三十分鐘、每周2到3次。每位受試者均接受訓練前、訓練後、訓練後二週和六週共四次評估。評估項目為脛前肌最大肌力。以SPSS 17.0 進行統計分析。結果：本論文結果以2篇已發表研討會摘要、1篇已發表科學文獻以及2篇撰寫中科學文獻分章呈現。第一篇為研討會摘要，探討近代肌電生物回饋儀輔助訓練對慢性腦中風患者動作功能的療效。主要結果發現肌電生物回饋儀輔助訓練應用於動態與功能性活動中對慢性腦中風患者動作功能更具療，詳細內容請參考本文第二章。第二篇為已發表科學文獻，以個案報告形式探討固定與變異練習的功能性肌電生物回饋儀輔助脛前肌肌肉訓練對慢性腦中風患者穿顱磁刺激誘發之脛前肌神經興奮性及行走相關之動作功能恢復的短期及長期療效。主要結果為固定練習模式的肌電生物回饋儀輔助脛前肌出力控制訓練似乎較變異練習模式對慢性腦中風患者之脛前肌最大肌力及穿顱磁刺激誘發之脛前肌神經興奮性有短期及長期療效，詳細內容請參考本文第三章。第三篇為撰寫中科學文獻，以隨機分組控制研究探討固定與變異練習的功能性肌電生物回饋儀輔助脛前肌肌肉訓練對慢性腦中風患者穿顱磁刺激誘發之脛前肌神經興奮性及行走相關之動作功能恢復的短期及長期療效。主要結果發現固定練習與變異練習組的受試者在訓練後、訓練後二週和六週，患側脛前肌最大肌力較對照組都有明顯的進步，但兩組的進步程度並無統計差異。然而，只有變異練習組的受試者在訓練後較對照組受試者明顯改善前、後位移的動態平衡能力；固定練習組在訓練後較對照組受試者顯著降低脛前肌的運動閾值。三組受試者訓練後在行走速度、計時起走測驗和六分鐘行走測驗均有顯著的進步，但無組間差異。詳細內容請參考本文第四章。第四篇為撰寫中科學文獻，探討訓練後脛前肌神經興奮性變化與動作功能改善的相關性。主要結果發現所有受試者在訓練後、訓練後二週和六週其脛前肌的運動閾值變化與脛前肌最大肌力和往前位移的動態平衡能力改善呈現顯著的負相關；脛前肌最大肌力的增加與往前位移的動態平衡能力的改善呈現顯著的正相關，詳細內容請參考本文第五章。第五篇為研討會摘要，探討高、低劑量肌電生物回饋儀輔助脛前肌肌肉訓練的療效。主要結果為高劑量訓練組比低劑量訓練組及對照組明顯改善脛前肌最大肌力，而低劑量訓練組及對照組無顯著改善。詳細內容請參考本為第六章。結論與臨床應用：功能性肌電生物回饋儀輔助之脛前肌肌肉訓練有效的促進慢性腦中風患者脛前肌肌力的進步。然而，唯有變異練習模式在訓練後療效可以轉移至動態平衡的進步，固定練習組在訓練後大腦皮質興奮性的明顯增強。高劑量的肌電生物回饋儀輔助之脛前肌肌肉訓練有效的改善脛前肌肌力，具有明顯的劑量反應關係。功能性肌電生物回饋儀輔助之脛前肌肌肉訓練誘發的大腦皮質興奮性增加分別造成脛前肌肌力增加和往前位移的動態平衡能力的改善相關，並不一定是大腦皮質興奮性增加造成脛前肌肌力增加近成改善往前位移的動態平衡能力。因此，功能性肌電生物回饋儀輔助之脛前肌肌力訓練是一種有效的脛前肌訓練模式，在患者能力許可下盡可能大量練習有助於脛前肌肌力的恢復。因為運動訓練誘發的大腦皮質興奮性增加對肌力增加或動態平衡能力恢復有獨立的影響力，因此肌力與平衡的動作訓練應該分別設計在腦中風和者的動作訓練中。

關鍵字

穿顱磁刺激 ； 肌電生物回饋 ； 動作功能 ； 神經塑性 ； 力量 ； 平衡 ； 劑量 ； 腦中風

並列摘要

Background: Impaired force level control is a major deficit of motor control in people with stroke. Electromyograghic biofeedback (EMGBFB) has been suggested by researchers and clinicians to be an useful and effective tool for enhancing control of force level during motor skill learning for people with stroke, but research literatures thus far have yet to provide convincing evidences to support this claim. According to motor learning theory, task-oriented, active learning, feedback manipulation and practice variation are key components to enhance motor function recovery. Developing functional EMGBFB-assisted muscle training based on motor learning concept is important for stroke rehabilitation. In addition, neural imaging studies have shown corresponding brain reorganization and neural plasticity following physical practice of movement skills in people with stroke. It is curious whether EMGBFB augmented physical practice of motor skills enhances brain reorganization. Using brain mapping techniques, in particular, the transcranial magnetic stimulation (TMS), we could investigate neural plasticity accompanying motor function changes induced by physical training, and hence may help to develop safer and more effective training parameters. The purposes of this study are (1) to update recent evidences regarding the effects of EMGBFB in people with stroke with a special emphasis on the outcome in the activity level of ICF model; (2) to determine the effects of constant or variable force exertion practice with 6-week functional EMGBFB-assisted tibialis anterior (TA) muscle training, according to the principles of motor learning, on the TA muscle strength, balance, lower limb motor function, and cortical excitability in people with chronic stroke; (3) to explore the relationship among cortical excitability, TA muscle strength, and motor function in hope to clarify the mechanisms underlying motor improvements after muscle training in stroke patients; (4) to investigate the effects of different doses of EMGBFB-assisted TA muscle training on TA muscle strength in people with chronic stroke. Study Design and Methods: First, randomized control studies about EMGBFB training of stroke were searched in MEDLINE, PEDro, CINAHL and Cochrane Library databases (to October 2011). The effects of EMGBFB in lower limb motor function were compared with conventional physical therapy alone. Second, three participants were randomly assigned to one of the three exercises programs: constant, variable or control to conduct a case-serial report. The constant and variable groups practiced TA muscle contractions with EMGBFB during functional activities for 6 weeks, in 18 sessions of 40 minutes each. Participants in the constant group aimed to produce 100% force output for each movement. Participants in the variable group aimed to produce force output of 100%, 75%, 50%, or 25% in random order. The control participants practiced upper extremity exercises. All participants were evaluated at baseline and at 1 day, 2 weeks, and 6 weeks post-training. Motor outcomes included TA muscle strength, dynamic balance test, walking speed, Timed Up and Go test (TUGT), and Six-minute Walk test (6MWT). TMS was used to measure the motor threshold (MT) and motor evoked potential amplitude (MEP amp). Third, thirty-three stroke participants were randomly assigned to one of three exercise groups: constant, variable, or control to conduct a randomized control study. Study method was descripted in previous case-serial report. Forth, changes in cortical excitability (TMS induced motor threshold, MT), TA muscle strength, and dynamic balance (anterior or posterior weight shift range) were observed longitudinally at baseline, posttest, 2 weeks, and 6 weeks follow up. Fifth, in the analysis about different doses of EMGBFB-assisted TA muscle training, partial data was collected from my previous published EMGBFB study in 2006. Forty participants were classified to one of the three exercise programs: high-EMGBFB (N=13), low-EMGBFB (N=12), or control (N=15). Subjects in the high-MMGBFB group were from constant group in this study, low-EMGBFBE was from previous study, and control group was from control group in both studies, Each program was 4~6 weeks in length, 30 minutes/section, and 2 or 3 sections per week. Each subject in the high-EMGBFB group practiced a total of 1440 trials (80 trials per session for 18 sessions), and the low-EMGBFB group practiced only 240 trials (20 trials per session for 12 sessions) of isotonic contractions in the affected TA muscle. The control group received regular physical therapy emphasizing the upper extremity movement. Affected TA muscle strength was evaluated at baseline, post-training, 2-week and 6-week after training. SPSS 17.0 was used for statistical analysis. Results: Two published abstracts of conferences, one published scientific article, and two ongoing scientific manuscripts were included. First one was a published conference abstract, the purpose was to update recent evidences regarding the effects of EMGBFB in people with stroke with a special emphasis on the outcome in the activity level of ICF model. The main results indicated that EMGBFB used in a dynamic and functional training mode is superior to conventional physical therapy alone for improving walking speed in people with stroke. Details were reported in Chapter II. Second one was a published scientific article, the purpose was to determine the effects of constant or variable force exertion practice with 6-week functional EMGBFB-assisted TA muscle training by a case-serial report. The preliminary data showed that 6-week of EMGBFB-assisted TA muscle training helped to improve TA strength immediately after training. The constant EMGBFB program also enhanced cortical excitability lasting for 6 weeks after training in stroke patients. The EMGBFB is a feasible and potentially effective adjunct therapy for improving TA control after stroke. Details were reported in chapter III. Third one was an ongoing scientific manuscript, the purpose was to further investigate the effect of functional EMGBFB-assisted TA muscle training. Both constant and variable groups showed significant improvements in TA strength. The variable group also showed significant improvements in dynamic balance. All participants showed improvements in walking speed, TUGT and 6MWT. The constant group showed a corresponding significant MT decrement after training. Details were reported in Chapter IV. Forth one was an ongoing manuscript, the purposes were to explore the relationship among cortical excitability, TA muscle strength, and dynamic balance in hope to clarify the mechanisms underlying motor improvements after muscle training in stroke patients. Significant negative correlation between MT and TA muscle strength and between MT and anterior weight shift range were found after training and at follow up. Positive relationship was found between TA muscle strength and anterior weight shift range after training and at 2 weeks follow up. Details were reported in chapter V. Fifth one was a published abstract of a conference, the purpose was to report the effects of different doses of EMGBFB-assisted TA muscle training on TA muscle strength in people with chronic stroke. The high-EMGBFB group showed significant improvement on affected TA muscle strength (p=0.004) compared with the low-EMGBFB and the control groups at post-training and follow-up. Details were reported in chapter VI. Conclusion: (1) Functional EMGBFB-assisted TA muscle training helped to improve strength and facilitate cortical excitability in patients with chronic stroke. Practicing variable force output with augmented faded feedback from the EMGBFB during functional movement transferred the training effects to balance function. (2) Higher dose of EMGBFB-assisted TA muscle training led to immediate and long-term improvement in muscle strength in chronic stroke patients. (3) The relationship between MT and strength or MT and balance was not dependent on the association between strength and balance. This implies that improved cortical excitability may independently contribute to muscle strength and balance function. Thus exercise training specifically for improving strength or improving balance function should be independently designed in stroke rehabilitation. This study highlights the importance of task-related training, motor learning principles and high dosage in EMGBFB training and provides evidence to further understand about the mechanism of motor function recovery induced by exercise training.

並列關鍵字

Electromyographic biofeedback ； motor ； force ； transcranial magnetic stimulation ； neuroplasticity ； dosage ； balance ； stroke

參考文獻

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