基于Granger因果分析的癫痫发作间歇期EEG在δ频段的功能连接模式

Functional connectivity of EEG＇s delta-band in epilepsy interictal seizures based on Granger causality analysis

目的应用频域Granger因果分析方法，研究颞叶癫痫发作间歇期16导脑电图（EEG）在与癫痫发作相关的δ频段的过度放电功能连接特性。方法实验数据来自颞叶癫痫9例患者（6例左颢叶癫痫，3例右颞叶癫痫），9例正常对照受试者。记录每例颞叶癫痫受试者在发作间歇期的痫样放电、非痫样放电以及正常对照组的共3个状态的16导EEG；每个状态下各记录10个EEG数据段，每个数据段长度为20s，采样频率为200Hz；应用带通滤波提取EEG的8分量（1—4Hz）。应用频域Granger因果分析方法，分别计算痫样放电组、非痫样放电组和正常组10次记录的16通道EEG8频段分量之间的频域因果度量平均值，5；分析以上3个组颞叶区（左颞叶癫痫：T3、T5，右颞叶癫痫：T4、T6）与额区（Fp1、Fp2、F3、F4）和顶区（C3、C4）之间EEG在8频段的功能连接模式。结果痫样放电组：下颞叶区（左下颞叶区T5，右下颞叶区k）与额区、顶区之间Iδ在0．1323±0．0329±0．1670±0．0289；非痫样放电组：下颞叶区与额区、顶区之间的，Iδ在0．0300±0．0130±0．0420±0．0072；正常对照组：下颞叶区与额区、顶区之间的Ig在0．0153±0．0028±0．0193±0．0057。统计结果表明：痫样放电组下颞叶区与额区、顶区之间的Ig值与非痫样放电组相比差异有统计学意义（P〈0．05），与正常对照组相比差异有统计学意义（P〈0．01）；非痫样放电组下颞叶区与额叶、顶叶之间的Iδ值和正常对照组相比差异无统计学意义（P〉0．05）。结论颞叶癫痫发作间歇期在痫样放电状态下，EEG8频段在下颞叶区与额区、顶区之间存在较强连接，过度放电从下颞叶区传递到额区和顶区。非痫样放电组和正常组的EEG8频段，下颞叶区与额叶、顶叶之间连接弱，下颞叶区不是EEG信号传导的起始区。

Objective The purpose of this research was to investigate functional connectivity of 16-channel electroencephalograph（EEG） in δ frequency band based on Granger causality analysis. Methods The experimental data was recorded at a sampling rate of 200 Hz from temporal lobe epilepsy （TLE） patients （6 left and 3 right TLE, and 9 normals as control group. Ten of EEG segments of 20 s length for three different states： epileptiform discharges （ED） state in interictal durations, non-ED state for TLE patients, and control state for the normal. The δ band components （I -4 Hz） were filtered from EEGs. The functional connection values Iδ between two EEG δ components were calculated separately by Granger causality analysis. The two EEG components were from inferoposterior temporal lobe （left： T5, right： T6 ） to frontal lobe （Fp1, F2, F3, F4）, and parietal lobe （C3, C4） for three states. Results The 18 values for ED state was 0.132 3±0.032 9±0.167 0±0.028 9, which was significantly higher than that of non-ED state （0.030 0±0.013 0-0.042 0±0.007 2） （P〈0.05）. The I8 values for the control group （0.015 3±0.002 8-0.019 3± 0.005 7） was much lower than that of ED state （P〈0.01）, and no obvious distinctions were observed compared with non- ED state at P=0.05 level. Conclusion There is a stronger connection of EEG＇ s δ bands from the inferoposterior temporal lobe to frontal and parietal lobe for the ED State, and the over-dischargel transmission is from inferoposterior temporal lobe to other brain regions. There is a weaker connection from the top temporal lobe to frontal and parietal lobe for non-ED state and control group, and the onset zones is not inferoposterior temporal lobe.