Altered Network Characteristics of Spike-Wave Discharges in Juvenile Myoclonic Epilepsy

Abstract

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.

Epilepsy-Related Brain Network Alterations in Patients With Temporal Lobe Glioma in the Left Hemisphere

“…These changes were not significant when comparing patients with GRE to healthy controls. Reduced global efficiency has been reported in idiopathic epilepsy patients (24)(25)(26)(27)(28); however, our findings differed from these results. This discrepancy may result from differences in pathogenesis and network reorganization (16)(17)(18).…”

Electroencephalography in the Diagnosis of Genetic Generalized Epilepsy Syndromes

“…Graph theory is increasingly being used as a tool to analyze epileptic networks. A recent study has reported increased local connectivity in the frontal regions with spike-wave discharges in JME ( 81 ). Another study based on graph theory using EEG data found similarities in network topology between patient with GGE and their unaffected relatives ( 82 ).…”

BOLD-fMRI activity informed by network variation of scalp EEG in juvenile myoclonic epilepsy

“…For the initiation and propagation of generalized discharges, cumulative evidences showed that aberrant thalamo-frontal circuit is the key element that contributes to GSWDs generation (Blumenfeld, 2003; Moeller et al, 2008; O'Muircheartaigh et al, 2011; Jiang et al, 2018). Moreover, it was suggested that widespread hyperconnectivity in sensorimotor and frontal cortex acts as the excitatory driver in discharge propagation (Vollmar et al, 2011; Clemens et al, 2013; Lee et al, 2017). Conversely, epileptic discharges, i.e., the sudden, transient disturbances of brain activity, can lead to abnormal organization of the diffuse brain networks (Engel et al, 2013).…”