開發並驗證乾式電極擷取腦波之無線裝置系統

Development and Validation of Wireless EEG Acquisition System with Dry Electrodes

沈昱樺(Yu-Hua Shen)

指導教授 ： 胡威志

中原大學/工學院/生物醫學工程研究所/碩士(2013年)

https://doi.org/10.6840/cycu201301055

摘要

隨著腦機介面產業的進步，腦機介面從原本的神經科學復健轉變為日常生活的裝置控制，所以對於腦波訊號的擷取也朝著更省時方便的目標前進，一般進行腦波量測時使用濕式電極所耗費於電極設置時間冗長，故本研究提出了利用乾式電極擷取腦波之無線裝置系統，此系統可省去也可以解決受測者與裝置之間有過多導線以致於受測者行動被限制的問題，也解決導線拉扯對於訊號所造成干擾，且搭配專屬腦波帽量測時，固定電極的方式可以減少電極移動所造成的雜訊，以避免訊號失真。
本系統包含類比訊號模組、訊號擷取模組、訊號處理模組，擷取一個通道心電圖(ECG)和六個通道腦波(EEG)的生理訊號，訊號採樣率為200Hz，藉由藍芽發射器將訊號傳至電腦儲存進一步分析，且本系統由電池供電，確保受測者電隔離的安全性。
腦波訊號的驗證利用閉眼放鬆休息及身心做較劇烈之互動遊戲兩種狀態來驗證儀器的實效性，受測者一共十人，且藉由心率變異度來確認受測者是否有在對的狀態下接受測試，由本系統量測到結果閉眼放鬆休息時的Alpha activity為0.377±0.061確實高於身心做較劇烈之互動遊戲0.153±0.035，利用T-TEST分析閉眼放鬆休息時和身心做較劇烈之互動遊戲的Alpha activity確實有統計上的顯著差異(P<0.05)，且結果閉眼放鬆休息時的Beta activity為0.211±0.026確實低於身心做較劇烈之互動遊戲0.430±0.045，利用T-TEST分析閉眼放鬆休息時和身心做較劇烈之互動遊戲的Beta activity確實有統計上的顯著差異(P<0.05)，由此可知本系統可以使用乾式電極擷取腦波訊號，達到以簡單方便的方式即可得到無失真且可分析的腦波訊號之目的。

關鍵字

腦機介面 ； 腦波 ； 心電圖 ； 乾式電極 ； 無線裝置

並列摘要

Recently, the research direction of Brain–Computer Interface (BCI) changed from the neuroprosthetics into the mind control devices. The functional brain wave acquiring system of BCI should advance on more convenient and easier to capture biopotential at scalp. The electroencephalogram (EEG) acquiring system of this study based on wireless EEG modules that can fit the BCI requirements for an easy placement or removal of the electrodes at the cap, especially with “dry electrodes”. The dry electrode allows for acquisition of EEG without using of collodion or gels. It can not only reduce time of setting up the electrode but also allows a long-term recording.
The system was integrated using a microprocessor (Ti MSP430-F149). It is to acquire six channels of EEG and one channel of ECG with a Bluetooth communication module that will send data to and receive command from a PC. The sample rate of this acquisition device was 200Hz. This battery-powered device overcomes the need of galvanic isolation.
The validation of EEG & ECG signal in this study has been tested with 10 subjects in two different conditions. One is at resting or meditation condition and the other is at mentally athletic condition. The heart rate variability (HRV) is to confirm the subject was in the right condition. With two conditions we could find the subjects have a higher power of Alpha activity at resting condition than mentally athletic condition. The average power of Alpha at resting condition was 0.377±0.061. And, the average power of alpha at mentally athletic was 0.153±0.035. There is a statistical significantly different of the Alpha activity between the two different conditions. And, the subjects have a higher power of Beta activity at mentally athletic condition than at resting condition. The average power of Beta at resting condition was 0.211±0.026. And, the average power of alpha at mentally athletic was 0.430±0.045. There is also a statistical significantly different of the Beta activity between the two different conditions. This study has shown that the system has acquired the reliable EEG signal. The study has also presented a wireless EEG acquisition system using dry electrodes.

並列關鍵字

Brain–Computer Interface ； electroencephalogram ； electrocardiogram ； dry electrodes ； wireless device

參考文獻

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