Zainuddin Zarita, Huong Lai Kee, Pauline Ong
School of Mathematical Sciences, Universiti Sains Malaysia.
Australas Med J. 2013 May 30;6(5):308-14. doi: 10.4066/AMJ.2013.1640. Print 2013.
Electroencephalogram (EEG) signal analysis is indispensable in epilepsy diagnosis as it offers valuable insights for locating the abnormal distortions in the brain wave. However, visual interpretation of the massive amounts of EEG signals is time-consuming, and there is often inconsistent judgment between experts.
This study proposes a novel and reliable seizure detection system, where the statistical features extracted from the discrete wavelet transform are used in conjunction with an improved wavelet neural network (WNN) to identify the occurrence of seizures.
Experimental simulations were carried out on a well-known publicly available dataset, which was kindly provided by the Epilepsy Center, University of Bonn, Germany. The normal and epileptic EEG signals were first pre-processed using the discrete wavelet transform. Subsequently, a set of statistical features was extracted to train a WNNs-based classifier.
The study has two key findings. First, simulation results showed that the proposed improved WNNs-based classifier gave excellent predictive ability, where an overall classification accuracy of 98.87% was obtained. Second, by using the 10th and 90th percentiles of the absolute values of the wavelet coefficients, a better set of EEG features can be identified from the data, as the outliers are removed before any further downstream analysis.
The obtained high prediction accuracy demonstrated the feasibility of the proposed seizure detection scheme. It suggested the prospective implementation of the proposed method in developing a real time automated epileptic diagnostic system with fast and accurate response that could assist neurologists in the decision making process.
脑电图(EEG)信号分析在癫痫诊断中不可或缺,因为它为定位脑电波中的异常畸变提供了有价值的见解。然而,对大量EEG信号进行视觉解读很耗时,而且专家之间的判断往往不一致。
本研究提出了一种新颖且可靠的癫痫发作检测系统,其中从离散小波变换中提取的统计特征与改进的小波神经网络(WNN)结合使用,以识别癫痫发作的发生。
在一个著名的公开可用数据集上进行了实验模拟,该数据集由德国波恩大学癫痫中心提供。首先使用离散小波变换对正常和癫痫性EEG信号进行预处理。随后,提取一组统计特征来训练基于WNN的分类器。
该研究有两个关键发现。第一,模拟结果表明,所提出的基于WNN的改进分类器具有出色的预测能力,总体分类准确率达到98.87%。第二,通过使用小波系数绝对值的第10和第90百分位数,可以从数据中识别出一组更好的EEG特征,因为在进行任何进一步的下游分析之前,异常值已被去除。
所获得的高预测准确率证明了所提出的癫痫发作检测方案的可行性。这表明所提出的方法有望用于开发一种实时自动癫痫诊断系统,该系统具有快速准确的响应,可协助神经科医生进行决策。