IEEE J Biomed Health Inform. 2016 May;20(3):873-879. doi: 10.1109/JBHI.2015.2424074. Epub 2015 Apr 17.
Long-term video EEG epilepsy monitoring can help doctors diagnose and cure epilepsy. The workload of doctors to read the EEG signals of epilepsy patients can be effectively reduced by automatic seizure detection. The application of partial directed coherence (PDC) analysis as mechanism for feature extraction in the scalp EEG recordings for seizure detection could reflect the physiological changes of brain activity before and after seizure onsets. In this study, a new approach on the basis of PDC was proposed to detect the seizure intervals of epilepsy patients. First of all, the multivariate autoregressive model was established for a moving window and the direction and intensity of information flow based on PDC analysis was calculated. Then, the outflow information related to certain EEG channel could be obtained by summing up the intensity of information flow propagated to other EEG channels in order to reduce the feature dimensionality. At last, according to the pathological features of epileptic seizures, the outflow information was regarded as the input vectors to a support vector machine classifier for discriminating interictal periods and ictal periods of EEG signals. The proposed method had achieved a good performance with the correct rate of 98.3%, the selectivity rate of 67.88%, the sensitivity rate of 91.44%, the specificity rate of 99.34%, and the average detection rate of 95.39%, which demonstrated that this method was suitable for detecting the seizure intervals of epilepsy patients. By comparing with other existing techniques, the proposed method based on PDC analysis achieved significant improvement in terms of seizure detection.
长期视频脑电图癫痫监测有助于医生诊断和治疗癫痫。自动发作检测可有效降低医生阅读癫痫患者脑电图信号的工作量。偏导相干性(PDC)分析作为头皮脑电图记录中用于检测发作的特征提取机制的应用,可以反映发作前后脑活动的生理变化。在这项研究中,提出了一种基于 PDC 的新方法来检测癫痫患者的发作间隔。首先,为移动窗口建立了多元自回归模型,并基于 PDC 分析计算了信息流的方向和强度。然后,通过将传播到其他 EEG 通道的信息流强度相加,可以获得与特定 EEG 通道相关的输出信息流,以减少特征维度。最后,根据癫痫发作的病理特征,将输出信息视为支持向量机分类器的输入向量,用于区分 EEG 信号的发作间期和发作期。该方法的正确识别率为 98.3%,选择性为 67.88%,灵敏度为 91.44%,特异性为 99.34%,平均检测率为 95.39%,表明该方法适用于检测癫痫患者的发作间隔。与其他现有技术相比,基于 PDC 分析的提出的方法在发作检测方面取得了显著的改善。