title: Source localization of the seizure onset zone from ictal EEG/MEG data.
abstract: Surgical treatment of drug-resistant epilepsy relies on the identification of the seizure onset zone (SOZ) and often requires intracranial EEG (iEEG). We have developed a new approach for non-invasive magnetic and electric source imaging of the SOZ (MSI-SOZ and ESI-SOZ) from ictal magnetoencephalography (MEG) and EEG recordings, using wavelet-based Maximum Entropy on the Mean (wMEM) method. We compared the performance of MSI-SOZ and ESI-SOZ with interictal spike source localization (MSI-spikes and ESI-spikes) and clinical localization of the SOZ (i.e., based on iEEG or lesion topography, denoted as clinical-SOZ).
  
  
  
  A total of 46 MEG or EEG seizures from 13 patients were analyzed. wMEM was applied around seizure onset, centered on the frequency band showing the strongest power change. Principal component analysis applied to spatiotemporal reconstructed wMEM sources (0.4-1 s around seizure onset) identified the main spatial pattern of ictal oscillations. Qualitative sublobar concordance and quantitative measures of distance and spatial overlaps were estimated to compare MSI/ESI-SOZ with MSI/ESI-Spikes and clinical-SOZ.
  
  
  
  MSI/ESI-SOZ were concordant with clinical-SOZ in 81% of seizures (MSI 90%, ESI 64%). MSI-SOZ was more accurate and identified sources closer to the clinical-SOZ (P = 0.012) and to MSI-Spikes (P = 0.040) as compared with ESI-SOZ. MSI/ESI-SOZ and MSI/ESI-Spikes did not differ in terms of concordance and distance from the clinical-SOZ.
  
  
  
  wMEM allows non-invasive localization of the SOZ from ictal MEG and EEG. MSI-SOZ performs better than ESI-SOZ. MSI/ESI-SOZ can provide important additional information to MSI/ESI-Spikes during presurgical evaluation. Hum Brain Mapp 37:2528-2546, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada.|Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Pellegrino
authors.affiliation: Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada.
authors.forename: Tanguy
authors.initials: T
authors.lastname: Hedrich
authors.affiliation: Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada.
authors.forename: Rasheda
authors.initials: R
authors.lastname: Chowdhury
authors.affiliation: Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada.
authors.forename: Jeffery A
authors.initials: JA
authors.lastname: Hall
authors.affiliation: Département de Génie Electrique, École de Technologie Supérieure, Montreal, Québec, Canada.|Centre De Recherches En Mathématiques, Montreal, Québec, Canada.|Centre D'etudes Avancées En Médecine Du Sommeil, Centre De Recherche De L'hôpital Sacré-Coeur De Montréal, Montreal, Québec, Canada.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Lina
authors.affiliation: Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada.
authors.forename: Francois
authors.initials: F
authors.lastname: Dubeau
authors.affiliation: Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada.
authors.forename: Eliane
authors.initials: E
authors.lastname: Kobayashi
authors.affiliation: Multimodal Functional Imaging Lab, Biomedical Engineering Department, McGill University, Montreal, Québec, Canada.|Neurology and Neurosurgery Department, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada.|Centre De Recherches En Mathématiques, Montreal, Québec, Canada.|Physics Department and PERFORM Centre, Concordia University, Montreal, Québec, Canada.
authors.forename: Christophe
authors.initials: C
authors.lastname: Grova
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D000069279:Drug Resistant Epilepsy / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D000069280:Electrocorticography / Q000379:methods; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D008953:Models, Anatomic; D064847:Multimodal Imaging; D011300:Preoperative Care; D025341:Principal Component Analysis; D012640:Seizures / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D058067:Wavelet Analysis; D055815:Young Adult
keywords: EEG; MEG; electric source imaging; epilepsy; inverse operator; localization; magnetic source imaging; seizure; source; spike