頸髓損傷患者輪椅太極拳訓練之神經生理效應

Abstract

背景：太極拳是中國傳統武術的一種，近年來受到西方醫學的注意，傳統站姿太極拳已被證實對於老年人和神經性疾患有所助益。然而，對於失能無法久站的患者，他們無法從事站姿太極拳訓練。因此，1997年，資深的太極拳教練楊東興先生創始了輪椅太極拳（Wheelchair Tai Chi）或稱為坐姿太極拳 (seated Tai Chi)，期望能使失能無法久站的患者也能接受輪椅太極拳的訓練。但是，輪椅太極拳的效果尚未被證明。 目的：本研究的目的是:（1）分析慢性頸髓不完全性損傷患者，接受八週輪椅太極拳訓練是否增進上肢神經生理之功能, 以及（2）量化輪椅太極拳的訓練強度。 方法：本研究徵召慢性頸髓不完全損傷（C2~C6，美國脊髓損傷學會分級ASIA C~D級）之受試者16位，分成輪椅太極拳訓練組與控制組。輪椅太極拳訓練組接受每次60分鐘，每週3次，共8週的訓練；控制組不接受任何訓練，並且維持原來的生活型態。輪椅太極拳訓練組與控制組均在訓練前、中、後進行神經生理的評估，包括測量橈側屈腕肌（Flexor carpi radialis）的運動神經元的興奮程度（如：最大H/M比值、H/M斜率比）、自主肌肉活化程度、最大自主收縮力量、與疲勞測試。並且，在訓練前，利用脊髓損傷獨立量表第二版（Spinal Cord Independence Measure, version II）評估受試者之功能獨立情況。另選擇一位輪椅太極拳教練及一位慢性頸髓不完全損傷患者評估輪椅太極拳訓練之心跳與攝氧量。 結果：輪椅太極拳訓練組8位（平均年齡42.6±9.4歲，平均身高164.4±5.2公分，平均體重65.1±11.2公斤）與控制組8位受試者（平均年齡38.5±13.2歲，平均身高166.1±9.9公分，平均體重61.5±12.7公斤）之年齡、身高、體重、脊髓受傷節數、受傷期間與脊髓損傷獨立量表無顯著差異。輪椅太極拳訓練組經過八週輪椅太極拳訓練之後，其最大自主收縮力量（由3.53±1.8公斤進步為5.09±2.6公斤，p=0.017）與自主肌肉活化程度（由47.35±17.35%進步為59.15±16.74%, p=0.012）有明顯進步，但是控制組之最大自主收縮力量與自主肌肉活化程度，在訓練前後是無顯著差異的。然而，輪椅太極拳訓練組與控制組之最大H/M比值與H/M斜率比，在訓練前、中、後，均未達顯著差異。而疲勞測試中，輪椅太極拳訓練組之疲勞指數與中樞疲勞指數在訓練八週後，有明顯改善，並且與控制組比較有顯著差異；而在控制組中，疲勞指數與中樞疲勞指數之下降程度在訓練前、中、後並無下降程度減緩之現象。而心肺反應分析顯示，輪椅太極拳的訓練強度為偏低，訓練心跳約70.5 下/分，強度約1.6 METs。 結論：八週之輪椅太極拳訓練可改善慢性脊髓不完全損傷患者之肌力與肌肉的耐力，其機轉可能與中樞神經興奮性的增加有關。但因脊髓神經元興奮性無明顯改變，因此可能主要受到大腦皮質重組而使下傳之皮質脊髓徑興奮性增加。建議需要進一步的研究證實大腦皮質的重組。

Background: Tai Chi or Tai Chi Chuan (TCC) is a traditional Chinese martial art and TCC in standing posture proved its benefits for the elderly and the individuals with neurological diseases. However, the disabled and deconditioned people are unable to do the traditional exercise in stance. Therefore, in 1997 Dong-Sing Yang, an experienced coach of Tai Chi, developed Wheelchair Tai Chi (WCTC) which is the modified TCC in sitting posture for them, but the training effects of WCTC are still unknown. Purpose: The purposes of this study were: (1) to investigate whether eight-week WCTC training would improve the neurophysiological function on upper extremity in subjects with chronic, incomplete cervical cord lesion, and (2) to quantify the intensity of WCTC during training. Methods: Sixteen individuals with chronic, incomplete cervical cord lesion (C2~C6, ASIA C~D) were recruited and assigned to WCTC group and control group. The WCTC training was conducted about 60 min per session, 3 sessions per week for eight weeks. Control group did not receive any training and kept their original lives. The neurophysiological assessments were executed before, during, and after WCTC training, including the measurement of the alpha motoneuron (MN) excitability (i.e. max H/M ratio, Hslp/Mslp ratio), maximal voluntary contraction (MVC), muscle voluntary activation, and fatigue test of flexor carpi radialis (FCR) muscles. Moreover, the Spinal Cord Independence Measure (SCIM, version II) was used to evaluate the clinical functional status. Furthermore, one WCTC coach and one chronic, incomplete SCL were selected to measure the heart rate and oxygen consumption during WCTC exercise. Results: Eight participants of WCTC group (mean age=42.6±9.4 yrs, mean height=164.4±5.2 cm, mean weight=65.1±11.2 kg) and 8 of control group (mean age=38.5±13.2 yrs, mean height=166.1±9.9 cm, mean weight=61.5±12.7 kg) were recruited. There were no significant differences in age, height, weight, injury level, injury duration and SCIM sores between two groups. After training, WCTC group increased significantly in MVC (from 3.53±1.8 kg to 5.09±2.6 kg，p=0.017), and muscle voluntary activation level (from 47.35±17.35% to 59.15±16.74%, p=0.012). In control group, no significant differences were found in MVC and muscle voluntary activation following eight weeks. However, there were no significant differences between WCTC and control groups in max H/M ratio and Hslp/Mslp ratio before and after training. Increased in fatigue index and central fatigue index were observed in WCTC group, whereas in control group. In terms of cardiopulmonary function, the results indicated that the training intensity was low with heart rate being about 70.5 bpm, and the METs being about 1.6. Conclusions: The eight-week WCTC training could improve muscle strength, muscle voluntary activation, and endurance in chronic, incomplete cervical cord lesion. The possible mechanism might be related to the enhancement of central neural drive in descending corticospinal tract. Since the MN excitability at spinal level did not change significantly, the change might be mainly due to cortical reorganization. Further study is suggested to investigate if cortical reorganization happens after training.