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Updated: May 13, 2026
Network Analysis of Foramen Ovale Electrode Recordings in Drug-resistant Temporal Lobe Epilepsy Patients
Published on: December 18, 2016
On the prognostic value of ictal EEG patterns in temporal lobe epilepsy surgery: a cohort study
Bruno Z Monnerat1, Tonicarlo R Velasco, João A Assirati
1Department of Neuroscience and Behavioral Sciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil. bzmonnerat@usp.br
Purpose:
To investigate the prognostic value of ictal scalp EEG patterns in drug-resistant temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) prior to undergoing temporal lobectomy.
Methods:
Scalp EEGs of the first seizure recorded during presurgical long-term video-EEG monitoring of 284 patients were reviewed. Patients were divided according to seizure laterality as either unilateral, when the EEG was restricted to one cerebral hemisphere for the entire seizure, or bilateral, when there was involvement of both hemispheres during the seizure. In patients with unilateral hippocampal sclerosis (HS), seizures were subdivided according to the side of initial ictal activity in relation to the side of the HS, as concordant, non-lateralising or contralateral. Postsurgical seizure outcome, according to Engel's classification, was verified at 1, 2, and 5 years after surgery.
Results:
There was no significant association between ictal EEG characteristics and postsurgical seizure outcome. An Engel I seizure outcome was observed in 87.1% of the patients with unilateral ictal EEGs and in 79.6% of those with bilateral ictal EEGs (p=0.092).
Conclusion:
Analysis of the localisation, morphology, and lateralisation of ictal EEG patterns did not provide prognostic information regarding seizure-free status in patients with MTLE-HS undergoing temporal lobectomy.
