Ictal EEG desynchronization during low-voltage fast activity for prediction of surgical outcomes in focal epilepsy

Lingli Hu; Kai Xiong; Lingqi Ye; Yuyu Yang; Cong Chen; Shan Wang; Yao Ding; Zhongjin Wang; Wenjie Ming; Zhe Zheng; Hongjie Jiang; Hong Li; Junming Zhu; Cenglin Xu; Yi Wang; Meiping Ding; Zhong Chen; Yingcai Wu; Shuang Wang

doi:10.3171/2022.11.JNS221469

Ictal EEG desynchronization during low-voltage fast activity for prediction of surgical outcomes in focal epilepsy

J Neurosurg. 2022 Dec 16;139(1):238-247. doi: 10.3171/2022.11.JNS221469. Print 2023 Jul 1.

Authors

Lingli Hu¹, Kai Xiong², Lingqi Ye¹, Yuyu Yang¹, Cong Chen¹, Shan Wang¹, Yao Ding¹, Zhongjin Wang¹, Wenjie Ming¹, Zhe Zheng¹, Hongjie Jiang¹, Hong Li³, Junming Zhu¹, Cenglin Xu⁴, Yi Wang⁴, Meiping Ding¹, Zhong Chen⁴, Yingcai Wu², Shuang Wang¹

Affiliations

¹ 1Department of Neurology, Epilepsy Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou.
² 2School of Computer Science and Technology, Zhejiang University, Hangzhou.
³ 3Department of Radiology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou; and.
⁴ 4Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou, China.

PMID: 36681967
DOI: 10.3171/2022.11.JNS221469

Abstract

Objective: The authors investigated alterations in functional connectivity (FC) and EEG power during ictal onset patterns of low-voltage fast activity (LVFA) in drug-resistant focal epilepsy. They hypothesized that such changes would be useful to classify epilepsy surgical outcomes.

Methods: In a cohort of 79 patients with drug-resistant focal epilepsy who underwent stereoelectroencephalography (SEEG) evaluation as well as resective surgery, FC changes during the peri-LVFA period were measured using nonlinear regression (h2) and power spectral properties within/between three regions: the seizure onset zone (SOZ), early propagation zone (PZ), and noninvolved zone (NIZ). Desynchronization and power desynchronization h2 indices were calculated to assess the degree of EEG desynchronization during LVFA. Multivariate logistic regression was employed to control for confounding factors. Finally, receiver operating characteristic curves were generated to evaluate the performance of desynchronization indices in predicting surgical outcome.

Results: Fifty-three patients showed ictal LVFA and distinct zones of the SOZ, PZ, and NIZ. Among them, 39 patients (73.6%) achieved seizure freedom by the final follow-up. EEG desynchronization, measured by h2 analysis, was found in the seizure-free group during LVFA: FC decreased within the SOZ and between regions compared with the pre-LVFA and post-LVFA periods. In contrast, the non-seizure-free group showed no prominent EEG desynchronization. The h2 desynchronization index, but not the power desynchronization index, enabled classification of seizure-free versus non-seizure-free patients after resective surgery.

Conclusions: EEG desynchronization during the peri-LVFA period, measured by within-zone and between-zone h2 analysis, may be helpful for identifying patients with favorable postsurgical outcomes and also may potentially improve epileptogenic zone identification in the future.

Keywords: EEG desynchronization; epilepsy surgery; focal epilepsy; low-voltage fast activity; surgical technique.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Drug Resistant Epilepsy* / surgery
Electroencephalography
Epilepsies, Partial* / surgery
Epilepsy*
Humans
Treatment Outcome