title: Seizure localization using three-dimensional surface projections of intracranial EEG power.
abstract: Intracranial EEG (icEEG) provides a critical road map for epilepsy surgery but it has become increasingly difficult to interpret as technology has allowed the number of icEEG channels to grow. Borrowing methods from neuroimaging, we aimed to simplify data analysis and increase consistency between reviewers by using 3D surface projections of intracranial EEG poweR (3D-SPIER). We analyzed 139 seizures from 48 intractable epilepsy patients (28 temporal and 20 extratemporal) who had icEEG recordings, epilepsy surgery, and at least one year of post-surgical follow-up. We coregistered and plotted icEEG β frequency band signal power over time onto MRI-based surface renderings for each patient, to create color 3D-SPIER movies. Two independent reviewers interpreted the icEEG data using visual analysis vs. 3D-SPIER, blinded to any clinical information. Overall agreement rates between 3D-SPIER and icEEG visual analysis or surgery were about 90% for side of seizure onset, 80% for lobe, and just under 80% for sublobar localization. These agreement rates were improved when flexible thresholds or frequency ranges were allowed for 3D-SPIER, especially for sublobar localization. Interestingly, agreement was better for patients with good surgical outcome than for patients with poor outcome. Localization using 3D-SPIER was measurably faster and considered qualitatively easier to interpret than visual analysis. These findings suggest that 3D-SPIER could be an improved diagnostic method for presurgical seizure localization in patients with intractable epilepsy and may also be useful for mapping normal brain function.
authors.affiliation: Department of Neurology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Neurology, Ewha Womans University School of Medicine and Ewha Medical Research Institute, 1071, Anyangcheon-ro, Yangcheon-gu, Seoul 158-710, South Korea.
authors.forename: Hyang Woon
authors.initials: HW
authors.lastname: Lee
authors.forename: Mark W
authors.initials: MW
authors.lastname: Youngblood
authors.forename: Pue
authors.initials: P
authors.lastname: Farooque
authors.forename: Xiao
authors.initials: X
authors.lastname: Han
authors.forename: Stephen
authors.initials: S
authors.lastname: Jhun
authors.forename: William C
authors.initials: WC
authors.lastname: Chen
authors.forename: Irina
authors.initials: I
authors.lastname: Goncharova
authors.forename: Kenneth
authors.initials: K
authors.lastname: Vives
authors.forename: Dennis D
authors.initials: DD
authors.lastname: Spencer
authors.forename: Hitten
authors.initials: H
authors.lastname: Zaveri
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Hirsch
authors.forename: Hal
authors.initials: H
authors.lastname: Blumenfeld
mesh_terms: D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D001931:Brain Mapping / Q000379:methods*; D004569:Electroencephalography / Q000379:methods*; D004827:Epilepsy / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D012640:Seizures / Q000473:pathology* / Q000503:physiopathology
keywords: Brain mapping; Electrocorticography (ECoG); Epilepsy; Outcome; Surgery