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ORIGINAL RESEARCH article

Front. Neurol.
Sec. Epilepsy
Volume 16 - 2025 | doi: 10.3389/fneur.2025.1446471

Secondary bilateral synchronization of interictal EEG discharges in focal epilepsy: prevalence and associated factors

Provisionally accepted
Polina Specktor Polina Specktor 1*Ronen Spierer Ronen Spierer 2Mark Katson Mark Katson 3Moshe Herskovitz Moshe Herskovitz 2,3
  • 1 Neurology, Carmel Medical Center, Haifa, Israel
  • 2 Rappaport Family Institute for Research in the Medical Sciences, The Ruth and Bruce Rappaport Faculty of Medicine, Technion Israel Institute of Technology, Haifa, Haifa, Israel
  • 3 Rambam Health Care Campus, Haifa, Haifa, Israel

The final, formatted version of the article will be published soon.

    Background: Epilepsy is commonly categorized based on etiology, treatment, and prognosis. Misclassification can occur due to the presence of interictal secondary bilateral synchronization (SBS) discharges seen on an electroencephalogram (EEG), misleading the classification process.Objective: To examine the prevalence of interictal SBS discharges in patients with focal epilepsy and to identify predictors of these discharges.Design: Retrospective analysis of patients who underwent long-term video EEG monitoring (LTVEM) from August 2001 to May 2014. Methods: We included patients with focal epilepsy. The patients were divided into two groups based on whether or not they had SBS discharges.Results: We found 1017 patients who underwent LTVEM. Of the 221 patients included in the final analysis, 36 (16%) exhibited SBS discharges. Patients in the SBS group were younger and had an earlier onset age of epilepsy. They also had higher rates of unclear seizure onset zone and focal to bilateral tonic-clonic seizures. In the binary logistic regression analysis, young onset age of epilepsy was the only significant factor.The prevalence of SBS discharges in focal epilepsy is relatively high (16%), emphasizing the importance of cautious interpretation of interictal EEG in epilepsy classification. Young age of disease onset is associated with higher rates of SBS.

    Keywords: Secondary bilateral synchrony, Epilepsy, interictal, EEG, Epileptiform discharges

    Received: 09 Jun 2024; Accepted: 21 Jan 2025.

    Copyright: © 2025 Specktor, Spierer, Katson and Herskovitz. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Polina Specktor, Neurology, Carmel Medical Center, Haifa, Israel

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.