title: Visual and semiautomated evaluation of epileptogenicity in focal cortical dysplasias - An intracranial EEG study.
abstract: The aim of the study was the evaluation of the added value of depth to subdural electrodes in delineating epileptogenicity of focal cortical dysplasias (FCDs) and to test the Epileptogenicity Index (EI) in this setting.
  
  
  
  Fifteen patients with FCD underwent iEEG with subdural and depth electrodes. Visual/EI analysis was performed in up to three habitual seizures per patient.
  
  
  
  Visual analysis: Grid onset seizures (n=10) started in electrodes overlying the lesion in 7 and remote from it in 3 cases. Depth onset seizures (n=7) affected only intralesional contacts in 4, intra- and extralesional in 2, and exclusively extralesional in 1 patient. Seizures started in depth and grid contacts simultaneously in 2 cases. EI analysis: The EI completely confirmed visual localization of seizure onset in 8 cases and depicted ictal onset-time accurately in 13. Beta/gamma ictal patterns were most reliably captured. Impact on surgical decision: Resection outline differed from MRI lesion in 7 patients based on grid and in three based on depth electrode information.
  
  
  
  In FCD, seizures can be generated within gyral/deep tissue appearing normal on imaging.
  
  
  
  Investigating FCD with subdural and depth electrodes is efficient to outline the seizure onset zone. The EI is a helpful additional tool to quantify epileptogenicity. Specific ictal patterns are prerequisite for reliable results.
authors.affiliation: NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology & National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, United Kingdom; Epilepsy Center, Department of Neurology, University Hospital Erlangen, Erlangen, Germany. Electronic address: Stephanie.gollwitzer@uk-erlangen.de.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Gollwitzer
authors.affiliation: NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology & National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, United Kingdom.
authors.forename: Ivan
authors.initials: I
authors.lastname: Valente
authors.affiliation: NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology & National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, United Kingdom; Epilepsy Society, Chalfont St Peter, SL9 0RJ, United Kingdom.
authors.forename: Roman
authors.initials: R
authors.lastname: Rodionov
authors.affiliation: NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology & National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, United Kingdom.
authors.forename: Catherine
authors.initials: C
authors.lastname: Scott
authors.affiliation: Clinical Neurosciences Department, King's College, NHS Foundation Trust, Denmark Hill, London SE5 9RS, United Kingdom.
authors.forename: Laura Mantoan
authors.initials: LM
authors.lastname: Ritter
authors.affiliation: NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology & National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, United Kingdom.
authors.forename: Tim
authors.initials: T
authors.lastname: Wehner
authors.affiliation: Epilepsy Center, Department of Neurology, University Hospital Erlangen, Erlangen, Germany.
authors.forename: Hajo M
authors.initials: HM
authors.lastname: Hamer
authors.affiliation: Service de Neurophysiologie Clinique, APHM, Hôpital de la Timone, 13005 Marseille, France; INSERM UMR 1106, INS, 27 Bd Jean Moulin, 13385 Marseille, France; Aix Marseille Université, Faculté de Médecine, Marseille, France; Hôpital Henri Gastaut, Etablissement Hospitalier Spécialisé dans le traitement des Epilepsies, 300 Boulevard de Sainte-Marguerite, 13009 Marseille, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bartolomei
authors.affiliation: NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology & National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, United Kingdom.
authors.forename: Beate
authors.initials: B
authors.lastname: Diehl
mesh_terms: D000328:Adult; D015331:Cohort Studies; D000069280:Electrocorticography / Q000379:methods; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D054220:Malformations of Cortical Development / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008875:Middle Aged; D012189:Retrospective Studies; D012640:Seizures / Q000000981:diagnostic imaging / Q000503:physiopathology; D013355:Subdural Space / Q000503:physiopathology; D013686:Telemetry / Q000379:methods; D016896:Treatment Outcome; D055815:Young Adult
keywords: Epilepsy surgery; Epileptogenicity Index; Focal epilepsy; SEEG