Dual Lesions Involving the Limbic System: A Stereoelectroencephalography Approach to Identifying the Epileptogenic Network and Applying Cortico-cortical Evoked Potential in Resection Planning
Abstract number :
1.317
Submission category :
9. Surgery / 9A. Adult
Year :
2023
Submission ID :
378
Source :
www.aesnet.org
Presentation date :
12/2/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Yong Seo Koo, MD PhD – Asan Medical Center
Boyoung Kim, MD – Fellow, Neurology, Asan Medical Center
Rationale: This study aims to investigate the efficiency of cortico-cortical evoked potential in analyzing epileptogenic network.
Methods: We report a case of a 33-year-old female drug-resistant epilepsy patient who had two distant encephalomalatic lesions in left anterior temporal lobe and left posterior cingulate gyrus. She underwent stereoelectroencephalography (SEEG), ictal and interictal single photon emission computed tomography (SPECT) and F-18 fluorodeoxyglucose positron emission tomography (FDG-PET). SEEG recordings captured ten focal impaired awareness seizure with behavior arrest and oro-alimentary automatism. While ictal and interictal SPECT and FDG-PET suggested left temporal lobe epilepsy, ictal EEG showed ictal onset in left anterior hippocampus with very rapid propagation to left insular lobe and left posterior cingulate gyrus. For evaluating the connectivity between two brain structural lesions, cortico-cortical evoked potential was done. Single-pulse electrical stimulation (SPES) was used for cortico-cortical evoked potential (0.3 millisecond pulses, 6-10 mA, 1 Hz).
Results: When stimulating electrodes implanted in left anterior hippocampal area, where all ten recorded seizures started according to SEEG, SPES responses were recorded in left post hippocampal area and left posterior insular area, which was concordant with the ictal SEEG propagation pattern. Stimulating left posterior insular area and left posterior cingulate gyrus evoked SPES responses in left middle cingulate gyrus, left posterior cingulate gyrus and left orbitofrontal area, which was also concordant with the findings in ictal SEEG. However, on the contrary, SPES responses were not seen in left anterior hippocampal area. This SPES results supports the SEEG data in assessing not only the connectivity between two brain areas but also the directions of the connection.
Conclusions: In dual limbic lesion epilepsy patients, differentiating the epileptogenic zone and propagation zone can be challenging, even in the help of SEEG. Cortico-cortical evoked potential can be useful in exploring ictal propagation patterns and epileptogenic networks.
Funding: This work was supported by grants (Grant No.: 2020IE0013-1, 2022IE0001-1, 2023IE0002-1) from Asan Medical Center, Asan Institute for Life Sciences, Seoul, Republic of Korea
Surgery