Abstracts

Rationale: Scalp EEG source imaging (ESI) has been established as a promising tool for epilepsy evaluation. However, the analysis of ictal data to localize the seizure onset zone is complex and difficult due to several reasons, including muscle and movement artifacts, low spatial resolution and insufficient synchronization during functional activity of the cerebral cortex. The goal of this study is to establish a robust approach of source localizations for ictal oscillations (0.1 - 120 Hz) during seizure onset and propagation of epileptiform discharges in patients using 256 dense-array EEG (dEEG) recordings and high-resolution individual head models. Methods: Our clinical procedures are (1) a physician visual identification of the seizure onset zone, (2) an inspection of ictal oscillations assisted by join time-frequency analysis, (3) a source localization of ictal oscillations and (4) a validation using interictal spike, intracranial EEG and surgical outcomes. Results: In this preliminary study, five patients with epilepsy were examined and validated. Multiple seizures from each patient were identified and consistently aligned with intracranial EEG and surgical outcomes localizations. The result supports the ability of the noninvasive dEEG recording to precisely and accurately localize the seizure onset zone. Conclusions: Therefore, the source localization of ictal oscillations using dEEG might help to guide the placement of invasive electrodes for the imaging seizure onset zone or provide more informative diagnoses for patient pre-surgical evaluation or treatment planning.