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A library of quantitative markers of seizure severity

Lookup NU author(s): Sarah Gascoigne, Dr Gabrielle SchroederORCiD, Dr Mariella Panagiotopoulou, Dr Jessica Blickwedel, Christoforos Papasavvas, Dr Rhys ThomasORCiD, Dr Kevin Wilson, Dr Peter TaylorORCiD, Dr Yujiang WangORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2023 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.Objective: Understanding fluctuations in seizure severity within individuals is important for determining treatment outcomes and responses to therapy, as well as assessing novel treatments for epilepsy. Current methods for grading seizure severity rely on qualitative interpretations from patients and clinicians. Quantitative measures of seizure severity would complement existing approaches to electroencephalographic (EEG) monitoring, outcome monitoring, and seizure prediction. Therefore, we developed a library of quantitative EEG markers that assess the spread and intensity of abnormal electrical activity during and after seizures. Methods: We analyzed intracranial EEG (iEEG) recordings of 1009 seizures from 63 patients. For each seizure, we computed 16 markers of seizure severity that capture the signal magnitude, spread, duration, and postictal suppression of seizures. Results: Quantitative EEG markers of seizure severity distinguished focal versus subclinical seizures across patients. In individual patients, 53% had a moderate to large difference (rank sum (Formula presented.), (Formula presented.)) between focal and subclinical seizures in three or more markers. Circadian and longer term changes in severity were found for the majority of patients. Significance: We demonstrate the feasibility of using quantitative iEEG markers to measure seizure severity. Our quantitative markers distinguish between seizure types and are therefore sensitive to established qualitative differences in seizure severity. Our results also suggest that seizure severity is modulated over different timescales. We envisage that our proposed seizure severity library will be expanded and updated in collaboration with the epilepsy research community to include more measures and modalities.

Publication metadata

Author(s): Gascoigne SJ, Waldmann L, Schroeder GM, Panagiotopoulou M, Blickwedel J, Chowdhury F, Cronie A, Diehl B, Duncan JS, Falconer J, Faulder R, Guan Y, Leach V, Livingstone S, Papasavvas C, Thomas RH, Wilson K, Taylor PN, Wang Y

Publication type: Article

Publication status: Published

Journal: Epilepsia

Year: 2023

Volume: 64

Issue: 4

Pages: 1074-1086

Print publication date: 01/04/2023

Online publication date: 02/02/2023

Acceptance date: 31/01/2023

Date deposited: 06/03/2023

ISSN (print): 0013-9580

ISSN (electronic): 1528-1167

Publisher: John Wiley and Sons Inc


DOI: 10.1111/epi.17525

PubMed id: 36727552


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Funder referenceFunder name
NIHR Biomedical Research Centre, Royal Marsden NHS Foundation Trust/Institute of Cancer Research