Network characteristics of genetic generalized epilepsy: Are the syndromes distinct?

OBJECTIVES

This study evaluated the structural and functional connectivity of patients with genetic generalized epilepsy (GGE) compared to healthy subjects. We also investigated whether there are differences in structural and functional connectivity among different GGE syndromes.

METHODS

We enrolled 100 patients with a clinical diagnosis of GGE. The patients were classified into different syndrome groups(12 cases of childhood absence epilepsy, 13 cases of juvenile absence epilepsy, 56 cases of juvenile myoclonic epilepsy, and 19 cases of epilepsy with GTC alone). We applied graph theoretical analysis to structural brain volumes and EEG to evaluate structural and functional connectivity in the GGE patients.

RESULTS

The global network measures showed significant differences in the structural and functional connectivity between the patients with GGE and the healthy controls, and the local network measures revealed hub reorganization in the GGE patients. The global efficiency, local efficiency, and clustering coefficients of the structural connectivity were significantly decreased, whereas the characteristic path length and small-worldness index were increased in the GGE patients. The global efficiency and local efficiency were increased and the small-worldness index decreased in the functional connectivity. The patients with juvenile myoclonic epilepsy had the most extensive changes in structural and functional connectivity compared to the healthy subjects.

SIGNIFICANCE

This study's main finding is that structural and functional connectivity in patients with GGE is significantly different from that in healthy controls. We find that the different GGE syndromes show distinct structural and functional connectivity, which can lead further understanding of the pathogenesis of GGE syndromes.