Stronger pre-surgical functional connectivity networks are associated with improved surgical outcome in temporal lobe epilepsy.

OBJECTIVE

This study investigates the network differences in pre-surgical resting-state EEG between individuals with unilateral temporal lobe epilepsy who become seizure-free and those who continue to have seizures after epilepsy surgery.

METHODS

We retrospectively identified 15 individuals with unilateral TLE who were seizure-free (SF) after epilepsy surgery and 13 who continued to have seizures post-surgery (nSF). Functional connectivity was measured using cross-correlation techniques on clips of resting-state scalp EEG that were free of any visually apparent epileptiform abnormalities.

RESULTS

Stronger pre-surgical functional connectivity was associated with favorable post-surgical outcomes. The SF group demonstrated significantly higher connectivity strength, particularly in cross-hemispheric and intra-hemispheric networks involving the ictal hemisphere (P = 0.02). Functional connectivity strength predicted post-surgical seizure freedom with 75 % accuracy (AUC = 0.77). Notably, individuals with the strongest connectivity were all seizure-free, despite heterogeneity in clinical characteristics or imaging findings. Connectivity strength did not correlate with age, disease duration, hippocampal sclerosis, or bilateral epileptiform abnormalities.

CONCLUSION

Functional connectivity networks derived from visually normal EEG can provide non-invasive, non-redundant information beyond traditional assessments to predict post-surgical outcomes.

SIGNIFICANCE: This study further supports the concept that epilepsy is a disorder of neural networks.