Seizure detection using ultra-long-term subcutaneous electroencephalography: A deep learning CNN-BiLSTM approach.
Sihyeong Park1, Jordan S Clark1, Pedro F Viana2,3,4
1Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA.
Epilepsia
|October 7, 2025
Summary
A new deep learning algorithm (CNN-BiLSTM) effectively detects seizures using subscalp electroencephalography (EEG). This automated method offers high sensitivity for epilepsy monitoring, improving upon traditional techniques.
Area of Science:
- Neuroscience
- Artificial Intelligence
- Medical Technology
Background:
- Ultra-long-term monitoring in epilepsy can yield novel insights but generates massive electroencephalographic (EEG) data.
- Manual review of extensive EEG data is impractical for identifying seizure patterns.
- Automated seizure detection is crucial for analyzing large datasets and enabling new therapeutic strategies.
Purpose of the Study:
- To develop and validate a deep learning algorithm for automated seizure detection.
- To utilize two-channel subscalp electroencephalographic (EEG) recordings for enhanced epilepsy monitoring.
- To improve the efficiency and accuracy of seizure detection compared to conventional methods.
Main Methods:
- A nine-layer convolutional neural network-bidirectional long short-term memory (CNN-BiLSTM) hybrid algorithm was developed.
- The algorithm processed 5-minute spectrograms with 50% overlap from retrospective subscalp EEG data of 16 patients.
- Performance was evaluated against a spectral power classifier and compared using intrapatient training-testing approaches.
Main Results:
- The CNN-BiLSTM algorithm trained on scalp and subscalp EEG achieved an AUROC of 0.98 and AUPRC of 0.50 (94% sensitivity, 1.11 false detections/day).
- Models trained solely on intracranial EEG (iEEG) or using only the first 45% of subscalp data showed lower performance.
- The CNN-BiLSTM detector significantly outperformed a conventional spectral band power detector.
Conclusions:
- A CNN-BiLSTM framework enables highly sensitive and specific automated seizure detection in two-channel subscalp EEG.
- Training with subcutaneous EEG data yields superior performance compared to intracranial EEG data.
- Augmenting training data with scalp EEG seizures proved beneficial for algorithm performance.


