低頻電刺激下皮膚阻抗量測裝置

Accessing the skin impedance under electric stimulation

江俊昇(Jiun-Sheng Jiang)

指導教授 ： 胡威志

中原大學/工學院/醫學工程研究所/碩士(2010年)

https://doi.org/10.6840/CYCU.2010.00019

摘要

神經肌肉電刺激在臨床上被許多物理治療師所使用在治療水腫的改善、促進血液循環、新陳代謝、疼痛減輕和傷口的修復等等。市面上許多電刺激器產品都是說明有所功效的，卻沒有給使用者在刺激時一個客觀療效的指標。本研究主要是建構一個可長期攜式可程式化低頻電刺激與阻抗量測裝置，在電刺激前後分別做0.1~500Hz多頻率阻抗量測，取得刺激前後阻抗與相位的資訊，了解電刺激對皮膚肌肉組織的變化，是否在刺激後皮膚阻抗有較大的差異。
本系統使用MSP430f149單晶片為核心，控制周邊電刺激電路與擷取、記錄阻抗變化資料，其內部AD模組將阻抗資料數位化，儲存至FLASH記憶體，並藉由USB通訊傳輸介面將資料傳至電腦端並於電腦端作進一步處理、分析(如阻抗雜訊濾除及計算出阻抗值與相位值)。電刺激電流範圍0.3~3mA(rms)，刺激頻率0.1Hz~10Khz。系統平台可直接由電腦端USB供電或鋰電池(3V~5V)供電，平均消耗電流約145mA/s，平均消耗功率為約0.5W/s。
此外本裝置在十位受測者中在刺激時量測即時阻抗的變化，在刺激前後量測0.1Hz~500Hz阻抗的變化，十位受測者在各頻率阻抗都呈現降低的現象，代表電刺激對於皮膚肌肉組織是有作用。這項阻抗變化的指標對於電刺激會增加血液循環或者新陳代謝可望提供了客觀電刺激療效的解釋。

關鍵字

神經肌肉電刺激器 ； 生物阻抗 ； 多頻率阻抗量測

並列摘要

Neuro-Muscular electrical stimulations were used by many physiotherapists to treat edema, to facilitate blood micro-circulation and metabolism, to ease pain and many others. Many electrical stimulators were claimed to be effective, but lack of objective indicator of treatment. This study is to discuss whether a bigger difference of skin impedance after stimulation exists. In order to analyze the impact of the stimulation on skin musculature, a low-frequency portable and programmable device measuring the magnitude and phase of impedance during electrical stimulation was built. The core processor of this system was the MSP430f149 microprocessor chip. That was used to control peripheral electric circuit of electrical stimulation, as well as to capture and to record the data of impedance change. The data were digitalized by its internal AD module, stored in the FLASH memory and transferred to the computer through USB for further analysis (for example, filtering the noise of impedance and calculating the magnitude and the phase of the impedance). The range of electrical stimulation current and frequency was 0.3~3mA /s and 0.1Hz~10 kHz, respectively. The system can be powered by USB or lithium battery (3V~5V), with the average current consumption approximately 145mA/s, and the average power consumption approximately 0.5W/s. Ten subjects were tested by this device to measure the real-time change of impedance during stimulation. The impedance declined as the probing frequency increased from 0.1Hz to 500 Hz for all subjects. This suggested that the electrical stimulation was effective. With respect to the perspective that electrical stimulation can facilitate the blood circulation or metabolism, this result could offer an objective explanation of electricity stimulation treatment.

並列關鍵字

Neuro-Muscular electrical stimulation ； bioimpedance ； Multi-frequency impedance measurements

參考文獻

[6]崔玖，介紹生物能信息醫學，國際醫學科學研究基金會 J Chin Med 12(4), pp.243-249, 2001.

[30]范綱榮，探討人體經絡之頻率響應，中原大學，2007.

[1]David M. Selkowitz, MS, RPT, High frequency electrical stimulation in muscle strengthening: A review and discussion. American Journal of Sports Medicine 17(1):103-111, 1989.

[2]Enoka RM, Muscle strength and its development. New perspectives. Sports Medicine 6:146-168, 1997.

[4]Hudlická O, Brown M, Cotter M, Smith M, Vrbová G.The effect of long-term stimulation of fast muscles on their blood flow, metabolism and ability to withstand fatigue. Pflugers Archives 369:141-149, 1997.