Zhang Zhongnan, Wen Tingxi, Huang Wei, Wang Meihong, Li Chunfeng
J Xray Sci Technol. 2017;25(2):261-272. doi: 10.3233/XST-17258.
Epilepsy is a chronic disease with transient brain dysfunction that results from the sudden abnormal discharge of neurons in the brain. Since electroencephalogram (EEG) is a harmless and noninvasive detection method, it plays an important role in the detection of neurological diseases. However, the process of analyzing EEG to detect neurological diseases is often difficult because the brain electrical signals are random, non-stationary and nonlinear.
In order to overcome such difficulty, this study aims to develop a new computer-aided scheme for automatic epileptic seizure detection in EEGs based on multi-fractal detrended fluctuation analysis (MF-DFA) and support vector machine (SVM).
New scheme first extracts features from EEG by MF-DFA during the first stage. Then, the scheme applies a genetic algorithm (GA) to calculate parameters used in SVM and classify the training data according to the selected features using SVM. Finally, the trained SVM classifier is exploited to detect neurological diseases. The algorithm utilizes MLlib from library of SPARK and runs on cloud platform.
Applying to a public dataset for experiment, the study results show that the new feature extraction method and scheme can detect signals with less features and the accuracy of the classification reached up to 99%.
MF-DFA is a promising approach to extract features for analyzing EEG, because of its simple algorithm procedure and less parameters. The features obtained by MF-DFA can represent samples as well as traditional wavelet transform and Lyapunov exponents. GA can always find useful parameters for SVM with enough execution time. The results illustrate that the classification model can achieve comparable accuracy, which means that it is effective in epileptic seizure detection.
癫痫是一种由大脑神经元突然异常放电导致的具有短暂脑功能障碍的慢性疾病。由于脑电图(EEG)是一种无害且非侵入性的检测方法,它在神经系统疾病的检测中发挥着重要作用。然而,分析脑电图以检测神经系统疾病的过程通常很困难,因为脑电信号是随机、非平稳和非线性的。
为了克服这一困难,本研究旨在基于多重分形去趋势波动分析(MF-DFA)和支持向量机(SVM)开发一种用于脑电图中自动癫痫发作检测的新型计算机辅助方案。
新方案在第一阶段首先通过MF-DFA从脑电图中提取特征。然后,该方案应用遗传算法(GA)来计算SVM中使用的参数,并使用SVM根据所选特征对训练数据进行分类。最后,利用训练好的SVM分类器来检测神经系统疾病。该算法利用SPARK库中的MLlib并在云平台上运行。
将该方案应用于一个公共数据集进行实验,研究结果表明,新的特征提取方法和方案能够以较少的特征检测信号,分类准确率高达99%。
MF-DFA是一种很有前景的脑电图分析特征提取方法,因为其算法过程简单且参数较少。通过MF-DFA获得的特征能够像传统小波变换和李雅普诺夫指数一样表征样本。GA在有足够执行时间的情况下总能为SVM找到有用的参数。结果表明该分类模型能够达到相当的准确率,这意味着它在癫痫发作检测中是有效的。