Association between disconnected networks and surgical outcome in drug-resistant temporal lobe epilepsy

To characterize alterations in structural network connection strength (SNCS), functional network connection strength (FNCS), and structural-functional correlation (SFC) of preoperative disconnected networks in temporal lobe epilepsy (TLE) and the association of these measures with postoperative seizure outcomes.

This retrospective cohort study enrolled 39 TLE patients with 29 healthy controls (HCs). Patients were divided into seizure-free (SF) (Engel Ia) and non-seizure-free (NSF) (Engel Ib-IV) groups. Each network was partitioned into predefined resection-anchored tiers, including three disconnected-network tiers and an unaffected network. SNCS and FNCS of each subnet were calculated, and SFC was analyzed.

Compared with HCs, both SF and NSF groups showed lower FNCS in the 1st-, 2nd-, and 3rd-level disconnected networks, and these patient-control differences remained significant after FDR correction. SNCS abnormalities were more localized, with a significant corrected pairwise difference observed only between SF and HCs in the 1st-level disconnected network. The SF-NSF differences in 3rd-level FNCS and 1st-level SNCS were observed only in uncorrected post-hoc analyses and did not survive FDR correction. SFC was significant in HCs at the 1st-, 2nd-, and 3rd-level disconnected networks after FDR correction, whereas no significant SFC was detected in either patient group. In exploratory linear regression analyses, the SF group showed a positive SFC at the 2nd-level disconnected network.

The SFC of disconnected networks showed widespread reductions in TLE. Exploratory analyses suggested that second-tier SFC may be related to postoperative seizure outcome, highlighting the potential relevance of resection-anchored network organization in TLE surgery.