Electroencephalogram source estimation

腦電波儀(EEG)是常常用來進行腦功能研究的工具之
一，因為它具有相當高的取樣頻率以及低廉的價位
，本研究中，我們將開發出一套系統，把EEG獲得
的頭皮電位資料，經過電腦處理，來估測目標腦波
訊號源的位置，本研究所採用的方法，包括了簡單
的頭模型(球模型)，正向模型的計算，以及最後逆向
問題計算。其正向模型是假設腦電波訊號源的位置
和方向是已知的，然後推導出頭皮的電位。逆向問
題則是由已知的頭皮電極點電位資料求出腦電波訊
號源的位置及方向；最後以臨床實驗:左右手分別出
力握拳，來檢驗我們系統所計算的位置是否在運動
神經區。實驗結果顯示，我們所開發系統的正確率
可達56%，已具有初步的實用性。
Electroencephalogram (EEG) is one of the tools widely
used in functional brain studies due to its high sampling
rate (temporal resolution) and low cost. In this
research, we proposed a system which used the scalp
potential data recorded by EEG to predict the location
of the target brain wave source. The techniques, used
in this experiment, included the simple head model, the
calculation of the forward model and the resolution of
the inverse problem. The forward model is based on the
hypothesis that both the brain wave source location and
the orientation are known, which can be used to infer
and predict the scalp potential. As for the inverse
problem, the location and the orientation of brain wave
source can be measured from the known scalp electrode
data. Through the clinical trial, we may examine the
system to see whether the location is shown in the motor
area of brain by using two hands to hold firmly. The
results indicate that the accuracy rate of this system can
be up to 56%, which achieves a preliminary
practicability.