Lee Chany, Im Chang-Hwan, Koo Yong Seo, Lim Jung-Ah, Kim Tae-Joon, Byun Jung-Ick, Sunwoo Jun-Sang, Moon Jangsup, Kim Dong Wook, Lee Soon-Tae, Jung Keun-Hwa, Chu Kon, Lee Sang-Kun, Jung Ki-Young
1 Department of Biomedical Engineering, Hanyang University, Seoul, Korea.
2 Department of Neurology, Korea University Medical Center, Korea University College of Medicine, Seoul, Korea.
Clin EEG Neurosci. 2017 Mar;48(2):111-117. doi: 10.1177/1550059415621831. Epub 2016 Jul 11.
Epilepsy is a disease marked by hypersynchronous bursts of neuronal activity; therefore, identifying the network characteristics of the epileptic brain is important. Juvenile myoclonic epilepsy (JME) represents a common, idiopathic generalized epileptic syndrome, characterized by spike-and-wave discharge (SWD) electroencephalographic (EEG) waveforms. We compare herein the network properties of periods of SWD and baseline activity using graph theory. EEG data were obtained from 11 patients with JME. Functional cortical networks during SWD and baseline periods were estimated by calculating the coherence between all possible electrode pairs in the delta, theta, alpha, beta and gamma bands. Graph theoretical measures, including nodal degree, characteristic path length, clustering coefficient, and small-world index were then used to evaluate the characteristics of epileptic networks in JME. We also assessed short- and long-range connections between SWD and baseline networks. Compared to baseline, increased coherence was observed during SWD in all frequency bands. The nodal degree of the SWD network, particularly in the frontal region, was significantly higher compared to the baseline network. The clustering coefficient and small-world index were significantly lower in the theta and beta bands of the SWD versus baseline network, but the characteristic path length did not differ among networks. Long-range connections were increased during SWD, particularly between frontal and posterior brain regions. Our study suggests that SWD in JME is associated with increased local (particularly in frontal region) connectivity. Furthermore, the SWD network was associated with increased long-range connections, and reduced small-worldness, which may impair information processing during SWD.
癫痫是一种以神经元活动超同步爆发为特征的疾病；因此，识别癫痫大脑的网络特征很重要。青少年肌阵挛性癫痫（JME）是一种常见的特发性全身性癫痫综合征，其特征为脑电图（EEG）波形出现棘慢波放电（SWD）。我们在此使用图论比较SWD期和基线活动期的网络特性。EEG数据来自11例JME患者。通过计算δ、θ、α、β和γ频段中所有可能电极对之间的相干性，估计SWD期和基线期的功能皮质网络。然后使用包括节点度、特征路径长度、聚类系数和小世界指数在内的图论测量方法来评估JME中癫痫网络的特征。我们还评估了SWD网络与基线网络之间的短程和长程连接。与基线相比，在所有频段的SWD期间均观察到相干性增加。SWD网络的节点度，尤其是额叶区域，与基线网络相比显著更高。SWD网络的θ和β频段的聚类系数和小世界指数显著低于基线网络，但各网络之间的特征路径长度没有差异。SWD期间长程连接增加，尤其是额叶和后脑区域之间。我们的研究表明，JME中的SWD与局部（尤其是额叶区域）连接性增加有关。此外，SWD网络与长程连接增加和小世界特性降低有关，这可能会损害SWD期间的信息处理。
