Idiopathic generalized epilepsies in the epilepsy monitoring unit: Systematic quantification of focal EEG and semiological signs

Johannes Koren; Clemens Lang; Gerhard Gritsch; Lisa Mayer; Manfred Hartmann; Sebastian Hafner; Tilmann Kluge; Christoph Baumgartner

doi:10.1016/j.clinph.2024.03.025

Idiopathic generalized epilepsies in the epilepsy monitoring unit: Systematic quantification of focal EEG and semiological signs

Clin Neurophysiol. 2024 Mar 30:162:82-90. doi: 10.1016/j.clinph.2024.03.025. Online ahead of print.

Authors

Johannes Koren¹, Clemens Lang², Gerhard Gritsch³, Lisa Mayer⁴, Manfred Hartmann³, Sebastian Hafner⁴, Tilmann Kluge³, Christoph Baumgartner⁵

Affiliations

¹ Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria; Department of Neurology, Clinic Hietzing, Vienna, Austria. Electronic address: johannes.koren@gesundheitsverbund.at.
² Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria; Department of Neurology, Clinic Hietzing, Vienna, Austria.
³ Center for Health & Bioresources, AIT Austrian Institute of Technology GmbH, Vienna, Austria.
⁴ Department of Neurology, Clinic Hietzing, Vienna, Austria.
⁵ Karl Landsteiner Institute for Clinical Epilepsy Research and Cognitive Neurology, Vienna, Austria; Department of Neurology, Clinic Hietzing, Vienna, Austria; Medical Faculty, Sigmund Freud University, Vienna, Austria.

PMID: 38603948
DOI: 10.1016/j.clinph.2024.03.025

Abstract

Objective: Focal seizure symptoms (FSS) and focal interictal epileptiform discharges (IEDs) are common in patients with idiopathic generalized epilepsies (IGEs), but dedicated studies systematically quantifying them both are lacking. We used automatic IED detection and localization algorithms and correlated these EEG findings with clinical FSS for the first time in IGE patients.

Methods: 32 patients with IGEs undergoing long-term video EEG monitoring were systematically analyzed regarding focal vs. generalized IEDs using automatic IED detection and localization algorithms. Quantitative EEG findings were correlated with FSS.

Results: We observed FSS in 75% of patients, without significant differences between IGE subgroups. Mostly varying/shifting lateralizations of FSS across successive recorded seizures were seen. We detected a total of 81,949 IEDs, whereof 19,513 IEDs were focal (23.8%). Focal IEDs occurred in all patients (median 13% focal IEDs per patient, range 1.1 - 51.1%). Focal IED lateralization and localization predominance had no significant effect on FSS.

Conclusions: All included patients with IGE showed focal IEDs and three-quarter had focal seizure symptoms irrespective of the specific IGE subgroup. Focal IED localization had no significant effect on lateralization and localization of FSS.

Significance: Our findings may facilitate diagnostic and treatment decisions in patients with suspected IGE and focal signs.

Keywords: Focal epileptiform discharges; Focal seizure symptoms; Idiopathic generalized epilepsy; Interictal epileptiform discharges; Video EEG monitoring.