Department of Medical Physics, Medical School, University of Ioannina, GR 451 10 Ioannina, Greece.
Comput Intell Neurosci. 2007;2007:80510. doi: 10.1155/2007/80510.
The recording of seizures is of primary interest in the evaluation of epileptic patients. Seizure is the phenomenon of rhythmicity discharge from either a local area or the whole brain and the individual behavior usually lasts from seconds to minutes. Since seizures, in general, occur infrequently and unpredictably, automatic detection of seizures during long-term electroencephalograph (EEG) recordings is highly recommended. As EEG signals are nonstationary, the conventional methods of frequency analysis are not successful for diagnostic purposes. This paper presents a method of analysis of EEG signals, which is based on time-frequency analysis. Initially, selected segments of the EEG signals are analyzed using time-frequency methods and several features are extracted for each segment, representing the energy distribution in the time-frequency plane. Then, those features are used as an input in an artificial neural network (ANN), which provides the final classification of the EEG segments concerning the existence of seizures or not. We used a publicly available dataset in order to evaluate our method and the evaluation results are very promising indicating overall accuracy from 97.72% to 100%.
癫痫患者的评估中,首要关注的是癫痫发作的记录。癫痫发作是指大脑局部或整体出现有节律性放电的现象,其个体行为通常持续数秒至数分钟。由于癫痫发作通常不频繁且不可预测,因此强烈建议在长时间脑电图(EEG)记录中自动检测癫痫发作。由于 EEG 信号是非平稳的,因此传统的频率分析方法在诊断目的上并不成功。本文提出了一种基于时频分析的 EEG 信号分析方法。最初,使用时频方法分析 EEG 信号的选定片段,并为每个片段提取几个特征,这些特征代表时频平面上的能量分布。然后,将这些特征作为人工神经网络(ANN)的输入,ANN 提供 EEG 片段是否存在癫痫发作的最终分类。我们使用了一个公开的数据集来评估我们的方法,评估结果非常有前景,表明总体准确率从 97.72%到 100%不等。