Brain-heart functional network dysfunction in temporal lobe epilepsy: A microstate-based analysis

Epilepsy patients face significantly elevated cardiovascular risks, with cardiac arrhythmias occurring 2-3 times more frequently than in the general population. Current knowledge of brain-heart functional coupling abnormalities in epilepsy, particularly during interictal periods, remains limited. We investigated brain-heart interplay characteristics in temporal lobe epilepsy through synchronized electroencephalographic-electrocardiographic analysis using a synthetic data generation model and microstate analysis.

We enrolled 52 patients with temporal lobe epilepsy (mean age = 33.4 ± 12.7 years) and 42 age-matched healthy controls (mean age = 31.95 ± 11.03 years). Twenty-minute artifact-free electroencephalographic segments were analyzed during resting states. Four directional brain-heart coupling sequences were extracted: C_Brain→HF, C_Brain→LF, C_HF→Brain, and C_LF→Brain, representing bidirectional interactions between brain activity and cardiac components.

Six microstate topologies were consistently identified across all brain-heart interplay sequences, with temporal lobe epilepsy patients demonstrating significantly more complex and unstable topological characteristics compared to healthy controls. For C_Brain→HF coupling, patients exhibited significantly reduced mean duration of microstate 3 (.34 ± .09 s vs. .38 ± .07 s, p = .02), increased occurrence rates of microstates 3 and 4 (both p < .001), and altered temporal coverage patterns. Similar abnormalities were observed across all sequences, with patients showing shortened microstate durations, altered occurrence rates, and disrupted temporal coverage. Spatial dissimilarity analysis revealed significant topological abnormalities across all microstates. A logistic regression model incorporating microstate parameters achieved 94.7% diagnostic accuracy for temporal lobe epilepsy, with an F1 score of .952 and an area under the curve of .932.

Temporal lobe epilepsy is characterized by profound disruptions in brain-heart functional coupling during interictal periods, manifesting as altered microstate topographies and temporal dynamics. These findings establish microstate-based analysis as a promising framework for characterizing brain-heart axis dysfunction in epilepsy.