電刺激的技術已經成功地應用在恢復中樞神經系統損傷病患的某些功能的缺失。傳統神經電刺激方法招募神經肌肉呈現反生理順序狀態，像是無法同時達到選擇性刺激小直徑神經纖維並且阻斷大直徑神經纖維。然而高頻阻斷是一種可行的電刺激技術可達到選擇性刺激與阻斷神經纖維。本研究目的在於建立一套實驗系統與動物模組來進行高頻阻斷的研究。

本研究選用紐西蘭白兔進行急性動物實驗。將一個五環的神經環電極架設在右側坐股神經上，在神經環電極近端(驅動刺激)與遠端(阻斷刺激)分別傳送兩頻道的刺激電流提供高頻阻斷研究；此外，在實驗中會藉由一套力矩量測系統來評估電刺激或阻斷時的表現。我們首先找出適當的驅電刺激參數可達到激發所有神經幹上的運動神經纖維，同時使得肌肉達到平順與最大僵直收縮；經由試驗三種不同的阻斷波形，包括單相、對稱雙相與不對稱方波來比較阻斷的效果並找出適當的阻斷參數；最後，藉由肌肉疲疺的實驗進行驗證高頻阻斷是否可以達到選擇性刺激與阻斷各種大小的神經纖維。

由動物實驗我們發現驅動刺激的頻率在60赫茲以上才能達到小於10%最大力矩之變異性的平順肌肉收縮。在每一次實驗都可得到等長招募曲線，之後選用雙相不對稱方波的阻斷刺激在不同的阻斷電流強度下會得到較好的阻斷效果；並且最大的調變範圍可達到百分之九十以上最大力矩輸出。在肌肉疲疺實驗，我們的結果已經證實在高頻阻斷下可以達到選擇性刺激較小的神經並且同時阻斷較大的神經。未來高頻阻斷技術的應用不僅是膀胱控制與痙攣抑制等神經義肢發展的基礎，更是一種新的工具可提供神經肌肉控制的研究。

Electrical stimulation techniques have been applied in restoration of certain dysfunctions in central nerve system lesion patients. Conventional neural stimulation method recruits the muscle nerves in a reverse order of physiologic manner, i.e., can not recruit small diameter nerve fibers without recruiting large diameter ones. However, high frequency blocking technique is a feasible method for achieving selective stimulation and blocking nerve fibers. The aim of the study is to establish an experiment system and animal model for high frequency blocking investigation.

In this study, we selected New Zealand white rabbit for acute animal study. A nerve cuff electrode with five rings was mounted on right side of sciatic nerve, and delivered two channels of stimulus current to nerve cuff at proximal site (for driving stimulus) and distal site (for blocking stimulus) for high frequency blocking investigation. Furthermore, a torque measurement system was established for assessing the stimulation or blocking performance in this study. We first find out suitable stimulation parameters for driving stimulus to activate all motoneuron fibers in nerve trunk and to produce smooth and tetanic muscle contraction. Three different blocking waveforms including monophasic, symmetric biphasic, and asymmetric biphasic waveforms, were tested to compare the blocking effects and to search for suitable blocking parameters. Finally, a muscle fatigue experiment was performed to verify whether high frequency blocking can selective stimulation and blocking varied sizes of nerve fibers.

From the animal studies, we found that at a stimulation frequency above 60 Hz smooth muscle contraction with small variation less 10 % of maximal torque can be achieved. After obtaining the isometric recruitment curves for each experiment, blocking stimulus with biphasic asymmetric waveform at varied blocking current amplitude shows better blocking effect. The maximal manipulation range can be above 90 % of maximal torque output. In muscle fatigue test, our results proved that high frequency blocking technique could achieve selective stimulation of smaller nerve fibers and blocking larger fibers. The development of high frequency blocking technique is not only a basis for developing the neural prostheses for bladder control and spasticity suppression, but also is a novel tool for neuromuscular control studies.

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