Foramen Ovale EEG Identifies Epileptogenic Zone in Mesial Temporal Lobe Epilepsy

EEG brain waves
EEG brain waves
The diagnostic tool may be especially useful in cases of nonlesional mesial temporal lobe epilepsy.
The following article is part of live conference coverage from the 2017 American Epilepsy Society Annual Meeting in Washington, DC. Neurology Advisor’s staff will be reporting breaking news associated with research conducted by leading experts in neurology. Check back for the latest news from AES 2017.

WASHINGTON, DC – Foramen ovale (FO) electroencephalography (EEG) is a useful, minimally invasive diagnostic tool for localizing the epileptogenic focus in nonlesional mesial temporal lobe epilepsy regardless of imaging showing presence of anatomic/functional brain lesion(s), according to data presented at the 2017 American Epilepsy Society Annual Meeting, December 1-5, 2017 in Washington, DC.

The study included 86 patients with possible MTLE with inconclusive scalp EEG recordings. The patients underwent FO EEG, and data was collected on age, sex, lesional status from MRI or PET findings, whether FO EEG was diagnostic, surgical status, and surgical outcomes, if applicable.

Among the 86 patients, FO EEG was diagnostic in 58 (67.4%), with 68 lesional and 18 nonlesional cases. FO EEG was diagnostic in 72.1% of lesional cases compared with 50% of nonlesional cases (P =.094). Overall, 46 patients underwent either anterior temporal lobectomy, other resection, vagal nerve stimulator placement, or responsive neurostimulation, with 25 lesional and 5 nonlesional cases undergoing anterior temporal lobectomy. The researchers observed no significant difference in surgical outcomes between the groups.

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Overall, the results suggest that FO EEG is a useful, minimally invasive diagnostic tool to help localize the epileptogenic focus in nonlesional MTLE, which is typically more difficult to diagnose and often multifocal. The results need to be replicated in larger nonlesional cohorts before being applied to clinical practice.

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Dolatshahi M, Bick S, Grannan B, Cole A, Eskandar E, Hoch D. Utility of foramen ovale electroencephalography to localize epileptogenic zone when imaging is inconclusive. Presented at: 2017 American Epilepsy Society Annual Meeting. December 1-5, 2017; Washington, DC. Abstract 3.158.