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Abstracts

Neural sensitization is a common feature of epileptic networks across diverse pathologies

Abstract number : 1.256
Submission category : 3. Neurophysiology / 3E. Brain Stimulation
Year : 2025
Submission ID : 1018
Source : www.aesnet.org
Presentation date : 12/6/2025 12:00:00 AM
Published date :

Authors :
Presenting Author: Ece Erder, MS – Wayne State University

Naoto Kuroda, MD, PhD – Wayne State University
Akari Ikeda, NA – Yokohama City University, School of Medicine
Yuri Yaguchi, NA – Yokohama City University, School of Medicine
Keisuke Hatano, MD, PhD – Wayne State University
Michael Cools, MD – Children's Hospital of Michigan
Aimee Luat, MD – Children’s Hospital of Michigan
Eishi Asano, MD, PhD – Wayne State University

Rationale: The seizure onset zone (SOZ) is a core component of the epileptic network and a key target for localizing the epileptogenic zone during presurgical evaluation. Cortico-cortical evoked potentials (CCEPs), elicited by single-pulse electrical stimulation (SPES), have been proposed as tools to assess local excitability and network dynamics. Although increased CCEP amplitudes at SOZ sites have been reported, it remains unclear whether such findings are consistent across different pathologies, including tumors, focal cortical dysplasia (FCD), tuberous sclerosis complex (TSC), and gliosis alone. We aimed to identify CCEP features that consistently characterize SOZ sites across diverse pathological substrates.
 


Methods: We studied 15 patients with drug-resistant epilepsy who underwent CCEP measurement during extraoperative intracranial EEG recording (5 tumors, 3 TSC, 2 FCD, 5 gliosis). CCEPs were elicited using SPES (5 mA, 1 Hz) delivered to adjacent electrode pairs over 40 trials. For each trial, N1 and N2 peak amplitudes were defined as the maximum evoked response occurring within 11–50 ms and 51–300 ms, respectively, and were z-score normalized using a −50 to −200 ms pre-stimulus baseline. For each site, we calculated the mean, standard deviation, and slope of peak amplitudes across trials. A linear mixed-effects model was applied within each pathology group to evaluate CCEP characteristics at SOZ sites, with Euclidean distance between stimulation and recording sites included as a covariate.

Results: Mean peak amplitude differences between SOZ and non-SOZ sites were not consistent across pathology groups. N1 peak amplitude was significantly reduced at SOZ sites in patients with tumors or gliosis. N2 amplitude was significantly reduced in tumors, FCD, and gliosis, but increased in TSC. In contrast, standard deviations of N1 and N2 amplitudes were consistently elevated at SOZ sites across all groups (N1 coefficient > 1.8, p < 0.001; N2 coefficient > 2.2, p < 0.001). Similarly, amplitude slopes over trials were consistently higher at SOZ sites (N1 slope > 0.014/trial, p < 0.001; N2 slope > 0.018/trial, p < 0.001).
Neurophysiology