Quantifying Interictal Spike Asymmetry on Scalp EEG to Lateralize the Seizure-Onset Zone in Temporal Lobe Epilepsy
4 affiliations
- 1Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia;
- 2Department of Computer and Information Sciences, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia;
- 3Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia;
- 4Department of Neurology, Massachusetts General Hospital, Boston;
Abstract
Background and objectives
Accurate lateralization of the seizure focus in temporal lobe epilepsy (TLE) is critical for surgical planning. Our current approach of capturing multiple seizures often misses bilateral disease because of seizure-onset variability. Interictal spike rate asymmetry is a promising marker of TLE laterality. However, visual analysis has low interrater reliability and cannot estimate long-term spike rates. This study evaluated whether asymmetry of automatically detected interictal spikes on scalp EEG can lateralize the clinician-annotated seizure focus in TLE.Methods
We performed a retrospective cohort study of patients with drug-resistant TLE who underwent scalp EEG recording at the Hospital of the University of Pennsylvania. Spike rates were quantified using a validated deep learning model, with a novel leave-one-hemisphere-out approach developed to lateralize the side of the spikes. We developed a logistic regression model to predict the clinician-determined laterality. Model performance was assessed using the area under the ROC curve (AUC), accuracy, and area under the precision-recall curve (AUPRC).Results
Of 365 included patients (205 women [56.2%]; median age 38, range 18-86 years), the training cohort comprised 261 patients and the independent, time-shifted validation cohort comprised 104. In the test cohort, classification of left TLE vs right/bilateral achieved an AUC of 0.78 (95% CI 0.69-0.87), an accuracy of 70%, and an AUPRC of 0.80 (95% CI 0.69-0.91), and classification of right TLE vs left/bilateral achieved an AUC of 0.80 (95% CI 0.70-0.88), an accuracy of 75%, and an AUPRC of 0.71 (95% CI 0.56-0.85). Model-surgery concordance was positively associated with favorable surgical outcomes. Engel I outcomes were associated with higher concordance probabilities (median difference = 0.20; 95% CI -0.02 to 0.39; r = 0.35; p = 0.037), and no significant association was observed for ILAE 1-2 (median difference = 0.20; 95% CI -0.06 to 0.38; r = 0.29; p = 0.084).Discussion
Interictal spike asymmetry on scalp EEG shows promise as a noninvasive lateralizing marker in TLE. Applying this model could confirm TLE laterality when it agrees with other noninvasive data or identify patients with a high likelihood of bilateral TLE, potentially avoiding un-necessary invasive studies and reducing the number of seizures needed for evaluation.
Related
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BibTeX
@article{kim2026quantifying,
title = {{Quantifying Interictal Spike Asymmetry on Scalp EEG to Lateralize the Seizure-Onset Zone in Temporal Lobe Epilepsy}},
author = {Juri Kim and Carlos A. Aguila and William K.S. Ojemann and Oluwatomisin Adenekan and Joshua Asuncion and Jin Jing and M. Brandon Westover and Kathryn A. Davis and Brian Litt and Erin C. Conrad},
journal = {Neurology open access},
year = {2026},
month = aug,
doi = {10.1212/wn9.0000000000000157},
url = {https://europepmc.org/article/PMC/PMC13718986},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Quantifying Interictal Spike Asymmetry on Scalp EEG to Lateralize the Seizure-Onset Zone in Temporal Lobe Epilepsy
AU - Juri Kim
AU - Carlos A. Aguila
AU - William K.S. Ojemann
AU - Oluwatomisin Adenekan
AU - Joshua Asuncion
AU - Jin Jing
AU - M. Brandon Westover
AU - Kathryn A. Davis
AU - Brian Litt
AU - Erin C. Conrad
PY - 2026
DA - 2026/08/12
JO - Neurology open access
DO - 10.1212/wn9.0000000000000157
UR - https://europepmc.org/article/PMC/PMC13718986
AB - Background and objectives Accurate lateralization of the seizure focus in temporal lobe epilepsy (TLE) is critical for surgical planning. Our current approach of capturing multiple seizures often misses bilateral disease because of seizure-onset variability. Interictal spike rate asymmetry is a promising marker of TLE laterality. However, visual analysis has low interrater reliability and cannot estimate long-term spike rates. This study evaluated whether asymmetry of automatically detected interictal spikes on scalp EEG can lateralize the clinician-annotated seizure focus in TLE.Methods We performed a retrospective cohort study of patients with drug-resistant TLE who underwent scalp EEG recording at the Hospital of the University of Pennsylvania. Spike rates were quantified using a validated deep learning model, with a novel leave-one-hemisphere-out approach developed to lateralize the side of the spikes. We developed a logistic regression model to predict the clinician-determined laterality. Model performance was assessed using the area under the ROC curve (AUC), accuracy, and area under the precision-recall curve (AUPRC).Results Of 365 included patients (205 women [56.2%]; median age 38, range 18-86 years), the training cohort comprised 261 patients and the independent, time-shifted validation cohort comprised 104. In the test cohort, classification of left TLE vs right/bilateral achieved an AUC of 0.78 (95% CI 0.69-0.87), an accuracy of 70%, and an AUPRC of 0.80 (95% CI 0.69-0.91), and classification of right TLE vs left/bilateral achieved an AUC of 0.80 (95% CI 0.70-0.88), an accuracy of 75%, and an AUPRC of 0.71 (95% CI 0.56-0.85). Model-surgery concordance was positively associated with favorable surgical outcomes. Engel I outcomes were associated with higher concordance probabilities (median difference = 0.20; 95% CI -0.02 to 0.39; r = 0.35; p = 0.037), and no significant association was observed for ILAE 1-2 (median difference = 0.20; 95% CI -0.06 to 0.38; r = 0.29; p = 0.084).Discussion Interictal spike asymmetry on scalp EEG shows promise as a noninvasive lateralizing marker in TLE. Applying this model could confirm TLE laterality when it agrees with other noninvasive data or identify patients with a high likelihood of bilateral TLE, potentially avoiding un-necessary invasive studies and reducing the number of seizures needed for evaluation.
SN - 2998-7601
ER -