小波分析用于颅内电极记录发作起始脑电图信号的研究

Analysis of intracranial electroencephalogram records during seizure onset using wavelet transform

目的初步研究颅内电极记录脑电图发作起始时期的小波熵变化趋势，探索其用于脑电图自动检测的前景。方法收集9例术后预后为EngelI级的癫痫患者，回顾性分析颅内电极脑电图记录到的28次发作事件，比较发作起始区（SOZ）电极和非SOZ电极在发作前、发作起始、发作中的小波熵变化情况。结果SOZ电极发作起始小波熵（0．326±0．250）较发作前背景（0．053±0．047）升高，发作中小波熵（0．138±0．097）较发作起始有所下降，差异有统计学意义（F：30．904，P=0．000）；非SOZ电极的小波熵在不同状态下未见明显变化。进一步将时窗小波熵用于发作起始脑电活动的检测显示，时窗小波熵可以敏感地反映出发作起始电活动的时间及电极。结论SOZ电极小波熵在发作起始时显著增高，可用于协助癫痫术前定位。

Objective To study the wavelet entropy of intracranial electrode recording electroencephalogram （EEG） during the seizure onset, and explore the prospect of applying it for automatic detection of EEG. Methods Twenty-eight seizure events of 9 epilepsy patients whose outcome were Engel class I were retrospective analyzed, by comparing the pre-ictal, initial ictal and ietal wavelet energy entropy variations of both seizure onset zone （SOZ） contacts and non-SOZ contacts. Results The wavelet energy entropy of SOZ contacts increased from pre-ietal （0. 053 ±0. 047） to initial ictal （0. 326 ±0. 250）, while it declined during the ictal （0. 138± 0. 097, F = 30. 904, P - 0. 000）. There was no obvious change of the wavelet energy entropy of non-SOZ contacts in different periods. By further applying time-window wavelet entropy to the detection of intracranial EEG, the results showed that the time-window wavelet energy entropy could be sensitive to reflect the seizure onset time and electrodes. Conclusion The wavelet energy entropy of contacts inside SOZ increased significantly at seizure onset, and this conclusion can be used to assist in presurgical localization of epilepsy.