Metabolic Brain Network Reorganization in Temporal Lobe Epilepsy With Aware or Impaired Awareness Seizures

Temporal lobe epilepsy (TLE) is increasingly recognized as a dysfunction of the brain network. However, the topological alterations of the metabolic brain network underlying impaired awareness seizures (IAS) remain unclear. In this study, we aimed to characterize metabolic network reorganization in patients with TLE and IAS (TLE-IAS) and to preliminarily investigate the specificity of these alterations by comparing the results with those of patients with TLE and aware seizures (AS).

This retrospective study included a total of 193 TLE-IAS patients, 30 patients with TLE-AS, and 193 controls. Metabolic brain networks were constructed for all groups, and nonparametric permutation testing was applied to compare group differences in graph-theoretical metrics and hub node distribution.

Compared with controls, both TLE patient groups exhibited globally weakened metabolic connectivity. Graph-theoretical analysis revealed that both groups demonstrated significant increases in characteristic path length and significant decreases in clustering coefficient (Cp). Furthermore, the TLE-AS group showed a significant decrease in local efficiency compared with controls. No statistically significant differences were found between the two patient groups across the four graph-theoretical parameters. Hub analysis revealed a convergent reorganization in both groups involving loss of default mode network hubs and a limbic/paralimbic shift, with the TLE-IAS group showing more limbic hubs, while the TLE-AS group exhibited more primary auditory hubs.

This study revealed alterations in graph-theoretical parameters and hub distribution in patients with TLE-IAS and TLE-AS. These findings provide preliminary metabolic imaging evidence for the neural substrates underlying impaired awareness in TLE.