Minimally Invasive Ictal EEG Source Localization Including Sphenoidal Electrodes
Abstract number :
2.097
Submission category :
3. Neurophysiology / 3G. Computational Analysis & Modeling of EEG
Year :
2023
Submission ID :
465
Source :
www.aesnet.org
Presentation date :
12/3/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Kara Götz, – Charité – Universitätsmedizin Berlin
Martin Holtkamp, MD – Department of Neurology with Experimental Neurology / Epilepsy-Center Berlin-Brandenburg – Charité – Universitätsmedizin Berlin; Bernd Vorderwülbecke, MD – Department of Neurology with Experimental Neurology / Epilepsy-Center Berlin-Brandenburg – Charité – Universitätsmedizin Berlin
Rationale:
Epilepsy surgery is a highly effective treatment option for drug-resistant focal epilepsy. As part of the presurgical assessment, ictal EEG Source Localization (ESL) can be utilized to identify the most likely source of an EEG signal within the brain. Based on surface EEG electrodes, ESL is usually a non-invasive diagnostic tool. To better capture EEG signals originating from temporo-basal brain areas, minimally invasive sphenoidal electrodes can be placed in the infratemporal fossa. So far, the impact of sphenoidal electrodes on ictal ESL has not been investigated. This retrospective study aimed at assessing the diagnostic sensitivity of ictal ESL with vs. without signal from sphenoidal electrodes.
Methods:
Inclusion criteria were (1) drug-resistant focal epilepsy, (2) presurgical long-term video-EEG monitoring with at least 31 surface electrodes (extended 10-20-system) and bilateral sphenoidal electrodes, (3) at least 3 recorded seizures, (4) a first resective epilepsy surgery, (5) subsequent seizure-freedom for at least 12 months (ILAE class 1 or 2), and (6) a minimum age of 18 years. Individual head models were created based on the presurgical structural MRI, with the sphenoidal electrodes included in the model. Per patient, up to 5 EEG seizure patterns were subjected to ESL. Each was analyzed separately with vs. without the signal from the sphenoidal electrodes. Diagnostic sensitivity was calculated as the proportion of seizures with maximum within the resected brain area out of the total number of seizures evaluated.
Results:
Forty-two patients were included in this study, of whom 20 (48%) were female and 39 (93%) had an anterior temporal lobe resection. The median age at surgery was 30 years (range 18-59 years). Altogether, 184 seizures were recorded (mean 4.4 per patient). With sphenoidal electrodes included vs. not included, 172 vs. 171 out of the 184 seizures could be evaluated (93.5% versus 92.9%). Ictal ESL including sphenoidal electrodes achieved a diagnostic sensitivity of 73% [95%-CI: 66-80%] as compared to 50% [95%-CI: 43-57%] without sphenoidal electrodes.
Conclusions:
The inclusion of sphenoidal electrodes significantly improved the diagnostic sensitivity of ictal ESL and can therefore be considered beneficial. As a limitation of this study, surface EEG did not include sub-temporal electrodes (F9/10 – P9/10). Further studies should evaluate the benefit of sphenoidal electrodes for ictal ESL when sub-temporal surface electrodes are included.
Funding:
BJV received the Otfrid Foerster scholarship 2021 from the German Society of Epileptology.
Neurophysiology