神經肌肉電刺激劑量對腦中風患者上肢動作功能恢復之療效研究

Abstract

上肢肢體無力是腦中風後常見的機能損傷，研究發現雖然有75%到83﹪的腦中風存活患者可以恢復行走能力，但卻只有約5%到20﹪的患者可以完全恢復上肢功能。在中風6個月後，仍有約40﹪到80%的上肢損傷患者無法有效的使用上肢而導致日常生活功能的障礙。文獻報導對於促進患側上肢動作恢復的治療方法應以主動的、重複的與特定性的訓練效果優良，然而對於尚處於軟癱（flaccid）或重度無力而缺乏主動動作的患者而言，這些主動運動訓練並不適用。因此臨床治療師往往必須尋求一些非主動療法來因應（如：連續被動關節運動儀器、電刺激、冷熱療、肩部滑輪被動關節運動等等）。 神經肌肉電刺激是臨床上容易取得的治療儀器，它可以在腦中風患者還未有能力參與主動動作時提供輔助性的治療，是腦中風臨床指引所建議的治療方法之一。過去研究曾發現電刺激對於腦中風患者的上肢動作功能恢復有正面的療效，但是這些研究所使用的治療劑量（每次電刺激的時間乘上頻率再乘上治療週數）差異頗大，且多數研究的治療時間較臨床常用的時間長而使得臨床應用困難。在目前復健治療的研究領域中，治療劑量對療效的影響是逐漸被重視的議題，越來越多的研究嘗試找出各種不同治療方式的治療劑量效應關係（dose-response relation）。因此本研究擬探討神經肌肉電刺激之不同劑量對於腦中風患者的上肢功能恢復之影響，期望能找出臨床上可行且有效的最小劑量。 本研究為施測者單盲隨機分組控制研究設計，從2004年5月到2008年12月，在台北2個醫學中心共收案95名腦中風發病後3個月內的單側偏癱個案。受試者隨機分配到四組（電刺激組_15分鐘、電刺激組_30分鐘、電刺激組_60分鐘、對照組）。所有受試者都接收一般所需之復健治療，電刺激組則另外接受為期4週，每週五次之電刺激（分別為15分鐘、30分鐘、與60分鐘/每次）。在治療前、後與治療後2個月接受評估。以傅格梅爾上肢評估量表（Fugl-Meyer Assessment Scale）、上肢動作評估量表（Action Research Arm Test）為主要評量結果（primary outcomes），動作活動日誌問卷（Motor Activity Log）為次要評量結果（secondary outcome）來評估受試者的上肢動作功能的恢復。在中風1年以後重新評估受試者的生活品質、日常生活功能、與上肢動作功能。 研究結果顯示：（一）、神經肌肉電刺激訓練能促進腦中風個案在傅格梅爾上肢評估量表和上肢動作研究表分數的進步，此進步量能維持到治療後2個月。（二）、神經肌肉電刺激訓練有促進腦中風患者在日常生活實際使用的頻率與動作品質的趨勢。（三）、每次15分鐘為期4週的最小電刺激劑量（5小時）就能促進促進腦中風個案上肢動作功能的進步。（四）、多重線性迴歸分析發現腦中風個案實際接受的電刺激的總劑量和上肢動作功能的進步量呈現正相關，電刺激的劑量越高上肢動作恢復得越好。（五）神經肌肉電刺激訓練對於中風二年後個案的生活品質、日常生活功能、與上肢功能沒有影響。 本研究雖然發現給予額外的神經肌肉電刺激能促進腦中風患者的上肢功能恢復，而且刺激的總劑量和恢復呈現正相關性。但是，在研究設計和結果解釋上仍有限制。由於本研究希望符合臨床的可行性，所以電刺激的總劑量的上限是20小時，每天的刺激劑量不超過1小時，遠比過去的研究少很多。所以由本研究結果無法推論到當電刺激劑量超過20小時或每次刺激時間超過1小時的情況下，是否是刺激劑量越高療效越好。此外由於電刺激總劑量是將每次電刺激時間、治療頻率、與療程週數相乘的總合，本研究只操弄每次電刺激的時間來改變總劑量，所以針對改變此三個參數對電刺激療效的影響目前仍有待未來的研究加以探討。由於本研究的設計是以上肢動作損傷較嚴重的腦中風個案為對象，且以目前臨床治療上可行的電刺激時間為研究參數。本研究的臨床價值在於可以作為臨床治療師在治療上肢偏癱較嚴重的中風個案時設計電刺激治療計劃的參考並提供未來想要探討電刺激強度效應研究的方向。

Stroke is a leading cause of mortality and disability in adult population. Paralysis of upper extremity is a major sequela after stroke and it limits the patient’s ability of performing activity of daily life independently. More than half of stroke survivors demonstrate moderate to severe arm dysfunction 6 months after stroke, and only 5% to 20% can fully recover. Past researches have shown that training programs emphasizing task-oriented, active participation and massive repetition are more effective for patients with stroke in improving upper extremity function. Yet these types of intervention typically require voluntary movement by the patients and hence can not be applied to patients in the acute flaccid stage or to patients with severe arm weakness. Thus, alternative assisted therapy, such as neuromuscular electrical stimulation (NMES), is generally applied clinically to facilitate motor recovery in early stage after stroke. Neuromuscular electrical stimulation (NMES) is an accessible modality in clinical setting and it can be applied to patients in flaccid stage. It has been proposed that electrical stimulation enhances motor recovery of upper extremity after acute stroke. With the use of NMES, patients with limited active movement can practice the movement to a fuller range, and patients with no or limited movement can receive abundant sensory input, which may facilitate reorganization of the central nervous system. But the dose of electrical stimulation varied widely among studies.The total hours of stimulation dosage may range from as little as 6 hours over 2 weeks to as much as 220 hours over 12 weeks. In addition, the long treatment duration proposed by the literature is not practical in common clinical settings. Issues of rationales for clinical applications of specific treatment parameters, such as treatment intensity or treatment dose have become the focus of current research in the field of stroke rehabilitation. The purpose of this study is to investigate the effects of different doses of NMES on upper extremity function in acute stroke patients with severe motor deficit and to investigate whether any dose-response of NMES and to find the minimal dosage applicable in clinical settings. This was an assessor-blind block randomized controlled study. During the period of May 2004 to December 2008, 95 stroke patients with unilateral involvement were recruited from two academic medical centers. Subjects were allocated randomly to the control group or each of the three NMES groups of varying dosages (15, 30, and 60 minutes per session). All subjects received regular inpatient rehabilitation. Treatment groups received additional NMES treatment sessions for 4 weeks, 5 times per week. Outcome measures included the upper extremity motor section of the Fugl-Meyer Motor Assessment Scale (FMA_UE), Action Research Arm Test (ARAT), and Motor Activity Log (MAL). The FMA_UE and ARAT were assessed at baseline, after 4 weeks of treatment, and at 2 months follow-up. The MAL was assessed only at follow-up. Quality of life (SSQOL, EQ5D), ADL function (Barthel index), and upper limb motor function (FMA, ARAT, MAL) were evaluated at one year post stroke. The results showed that: (1) NMES facilitates motor function recovery of affected upper extremities after stroke and the improvement was maintained at 2 month follow-up; (2) There was a trend toward improvement in the MAL scores in the NMES groups at 2-month follow up; (3) The minimal effective dosage was 5 hours of NMES for improvement of upper limb function in stroke patients; (4) There was a positive relationship between actual stimulation dosage of NMES and upper limb functional recovery. Increasing the stimulation dose of NMES led to greater improvement in the ARAT score at follow-up; (5) No significant difference was found between NMES groups and the control group in quality of life, ADL and upper limb function at post stroke 2-year follow-up. There were some limitations in the present study. The NMES dosage in our study was limited to 0 to 20 hours. This range is narrower than those used in most studies. We thought that our range was more practical for clinical application. However, our result cannot be generalized to clinical practices where the total treatment time exceeds 20 hours, nor can our results be applied to treatment programs exceeding 1 hour/session. More studies are needed to develop the dose-response curve and to find the optimal NMES dosage or minimal effective dosage in improving upper limb function. Another concern was that treatment dose had been defined as the product of stimulation time per session, treatment frequency, or treatment duration. Future studies should investigate varying combinations of treatment dose administration for designing intervention programs suitable for clinical practice. The clinical value of this study is to provide the references in NMES intervention program design for stroke patients with severe motor deficits in clinical practice and point out some viewpoints regarding dose-response relation between NMES and functional outcome in future studies.