Evaluation of Postictal Electroencephalogram (EEG) Slowing and Development of a Postictal EEG Source Imaging Technique to Localize Seizure Onset in Epilepsy (RPA Pilot / Seed Project)

The localization of the seizure onset zone is critical for the successful surgical management of refractory epilepsy. Although postictal electroencephalogram (EEG) has shown the potential to obtain additional localizing and lateralizing information, current studies fail to provide generalized conclusions explaining its key features and their association with the seizure onset. Furthermore, despite the potential importance of postictal EEG localization, EEG source imaging (ESI) has traditionally been restricted to the interictal and ictal periods, neglecting the postictal period, and no foundational study exists to provide a strategy for postictal ESI. Even though well-established ESI techniques on interictal EEG have provided assistive diagnostic information on seizure onset localization in refractory focal epilepsy, strategies for postictal EEG have not been adequately studied. To address these gaps, we will perform a spectral analysis of postictal slow waves (delta frequency, <4Hz), which is a key characteristic of postictal EEG, for its predictive value in seizure onset localization. We expect that our novel approach for postictal EEG will complement established interictal and ictal strategies with a new diagnostic tool that can improve seizure localization in epilepsy to ultimately assist clinical decision-making.