基于部分定向相干法的脑网络特征分析

Analysis of Brain Network Characteristics Based on Partial Directed Coherence Method

目的研究儿童癫痫患者在发作间期与发作期脑电信号特征的异同。方法采用23名儿童患者139次EEG数据,进行部分定向相干因果性(partial directional coherences,PDC)分析,基于显著性水平的方法选取阈值,在此阈值下,建立δ波、θ波和α波的脑功能网络连接图,并从出度和聚类系数角度分析脑区的网络特征。结果在癫痫发作间期与人体视觉、体觉及精神功能相关的枕叶区、顶叶区、额叶区脑网络节点出度值总体减弱,而与听觉功能相关的颞叶区节点出度值增大。聚类系数则相反,枕叶区、顶叶区、额叶节点的聚类系数总体处于较高水平,但在左、右大脑分割位置的节点及颞叶节点聚类系数减小。结论儿童患者在癫痫发作时与视觉、体觉、思维等相关的脑区功能减弱,而听觉功能疑似增强,出现了不同于发作间期的异常现象。

Objective In order to study the characteristics of EEG signals in children with epilepsy during the interictal and ictal periods.Methods Partial directional coherences(PDC)in the EEG recording channels were analyzed as a measure of causality in 139 seizure datasets recorded from 23 children.Functional brain network maps ofδwaves,θwaves,andαwaves were then established.The networks identified during interictal and ictal periods were investigated,and the out-degree and clustering coefficient were utilized to assess the connectivity.Results The data showed that the out-degrees of the brain network nodes in the frontal,parietal,and occipital lobes were generally reduced during the ictal period,while the nodal degree in the temporal lobe was increased.On the contrary,the clustering coefficients of the nodes in the occipital,parietal,and frontal lobes were higher comparing to the clustering coefficients of the nodes in the temporal lobe and the nodes located along the longitudinal fissure.Conclusion In children with epilepsy,the brain function related to vision,body sense and thinking was weakened,while the auditory function was suspected to be enhanced,which was different from the abnormal phenomena in the interval of epilepsy.