Network coupling and surgical treatment response in temporal lobe epilepsy: A proof-of-concept study

Objective: This proof-of-concept study aimed to examine the overlap between structural and functional activity (coupling) related to surgical response. Methods: We studied intracranial rest and ictal stereoelectroencephalography (sEEG) recordings from 77 seizures in thirteen participants with temporal lobe epilepsy (TLE) who subsequently underwent resective/laser ablation surgery. We used the stereotactic coordinates of electrodes to construct functional (sEEG electrodes) and structural connectomes (diffusion tensor imaging). A Jaccard index was used to assess the similarity (coupling) between structural and functional connectivity at rest and at various intraictal timepoints. Results: We observed that patients who did not become seizure free after surgery had higher connectome coupling recruitment than responders at rest and during early and mid seizure (and visa versa). Significance: Structural networks provide a backbone for functional activity in TLE. The association between lack of seizure control after surgery and the strength of synchrony between these networks suggests that surgical intervention aimed to disrupt these networks may be ineffective in those that display strong synchrony. Our results, combined with findings of other groups, suggest a potential mechanism that explains why certain patients benefit from epilepsy surgery and why others do not. This insight has the potential to guide surgical planning (e.g., removal of high coupling nodes) following future research.

Automated summary

This proof-of-concept study examined the overlap between structural and functional activity related to surgical response and found that structural networks are associated with functional activity in TLE. Patients with poor seizure control after surgery had higher synchrony between structural and functional networks, suggesting that intervention targeting these networks may be ineffective for these patients.