title: Localization of Epileptogenic Zone on Pre-surgical Intracranial EEG Recordings: Toward a Validation of Quantitative Signal Analysis Approaches.
abstract: In patients diagnosed with pharmaco-resistant epilepsy, cerebral areas responsible for seizure generation can be defined by performing implantation of intracranial electrodes. The identification of the epileptogenic zone (EZ) is based on visual inspection of the intracranial electroencephalogram (IEEG) performed by highly qualified neurophysiologists. New computer-based quantitative EEG analyses have been developed in collaboration with the signal analysis community to expedite EZ detection. The aim of the present report is to compare different signal analysis approaches developed in four different European laboratories working in close collaboration with four European Epilepsy Centers. Computer-based signal analysis methods were retrospectively applied to IEEG recordings performed in four patients undergoing pre-surgical exploration of pharmaco-resistant epilepsy. The four methods elaborated by the different teams to identify the EZ are based either on frequency analysis, on nonlinear signal analysis, on connectivity measures or on statistical parametric mapping of epileptogenicity indices. All methods converge on the identification of EZ in patients that present with fast activity at seizure onset. When traditional visual inspection was not successful in detecting EZ on IEEG, the different signal analysis methods produced highly discordant results. Quantitative analysis of IEEG recordings complement clinical evaluation by contributing to the study of epileptogenic networks during seizures. We demonstrate that the degree of sensitivity of different computer-based methods to detect the EZ in respect to visual EEG inspection depends on the specific seizure pattern.
authors.affiliation: Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: Ralph G
authors.initials: RG
authors.lastname: Andrzejak
authors.affiliation: Brain Function and Neuromodulation, Université Joseph Fourier, Grenoble, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: David
authors.affiliation: Unit of Experimental Neurophysiology and Epileptology, Fondazione Istituto Neurologico Carlo Besta, Milan, Italy.
authors.forename: Vadym
authors.initials: V
authors.lastname: Gnatkovsky
authors.affiliation: INSERM, U1099, Université de Rennes 1, LTSI, 35000, Rennes, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Wendling
authors.affiliation: INSERM, U1106, Clinical Epileptology Unit, La Timone, 13000, Marseille, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bartolomei
authors.affiliation: Claudio Munari Epilepsy Surgery Center, Ospedale Niguarda Ca' Granda, Milan, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Francione
authors.affiliation: Epilepsy Unit, Neurology & Psychiatry Department, Grenoble University Hospital, Grenoble, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Kahane
authors.affiliation: qEEG Group, Department of Neurology, Inselspital, Bern University Hospital, University of Bern, 3010, Bern, Switzerland.
authors.forename: Kaspar
authors.initials: K
authors.lastname: Schindler
authors.affiliation: Unit of Experimental Neurophysiology and Epileptology, Fondazione Istituto Neurologico Carlo Besta, Milan, Italy. decurtis@istituto-besta.it.
authors.forename: Marco
authors.initials: M
authors.lastname: de Curtis
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology / Q000503:physiopathology*; D001931:Brain Mapping; D058256:Brain Waves / Q000502:physiology*; D004569:Electroencephalography; D004827:Epilepsy / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
keywords: Computer-based signal analysis; Epilepsy surgery; Epileptogenic zone; Focal epilepsy; Intracranial EEG