微肌肉振動對中風患者手指牽張反射之影響

Abstract

研究指出施予正常人手部一80Hz特定肌肉微幅振動，可提高受振動刺激手指之運動誘發電位(Motor Evoked Potentials, MEPs)，且會抑制鄰近手指肌肉之MEPs，故可能對中風復健有所幫助。而振動對於運動誘發電位的影響可分為大腦皮質與脊髓兩部份，先前研究仍無法釐清振動在脊髓神經通路的貢獻，故本研究針對中風患者牽張反射進行研究，釐清微肌肉振動對牽張反射之影響，並開發一系統在肌肉收縮達到一目標範圍下自動誘發受測者牽張反射，並以程式之邏輯自動篩選判斷、量化反射訊號，也就是建立一量化微肌肉振動對牽張反射訊號影響之方法。共四位中風受測者參與本研究，結果顯示給予手指微肌肉振動(80Hz、不誘發張力性振動反射與假想動作的最大振幅)，可能抑制短潛期牽張反射峰值(M1 peak)。受測者手指肌肉平均M1 peak在無肌肉振動為79.46%MVC (Maximal volunteer contraction)，而有肌肉振動為71.53%MVC。故微肌肉振動對於中風患者脊髓可激度可能無正向的貢獻。此外本研究利用程式來篩選牽張反射之系統也可以較客觀的選出Trials間相關係數高的牽張反射。

Previous studies have shown that muscle vibration (MV), below the threshold of inducing illusory movement or tonic vibration reflex, could modulate motor-evoked potentials (MEPs) of pathways controlling hand muscles in intact individuals. It is evident that this type of sub-threshold muscle vibration provides corticomotor modulations on the pathways controlling the vibrated and adjacent non-vibrated muscles. However, spinal-level contribution to the muscle vibration-induced changes in MEPs is not clear. We proposed a systematic approach for inducing and quantifying stretch reflex in strokes, and examined the effects of muscle vibration on the excitability of the spinal neural pathway. There muscles were examined: first dorsal interossei (FDI), abductor pollicis brevis (APB) and abductor digiti minimi (ADM). We tested four stroke subjects in our study. The results indicated that the amplitudes of short-latency stretch reflex (M1 Peak) of the three finger muscles were depressed during muscle vibration as compared to those with no vibration (MV: 71.53%MVC vs. No MV: 79.46%MVC). Muscle vibration did not affect the latency of either M1 or M2. These findings suggest that muscle vibration-induced MEPs facilitation may not occur in the spinal-level pathway. In addition, we also proposed a systematic approach for selecting stretch reflex with high correlation between trials.