title: What is the concordance between the seizure onset zone and the irritative zone? A SEEG quantified study.
abstract: OBJECTIVE
  In focal epilepsies, the accurate delineation of the epileptogenic network is a fundamental step before surgery. For years, the relationship between the interictal epileptic spikes (defining the "irritative zone", IZ) and the sites of seizure initiation (SOZ) has been a matter of debate.
  
  
  METHODS
  Our goal was to investigate from intracerebral recordings (stereoelectroencephalography, SEEG) the distribution of interictal epileptic spikes (based on a spike frequency index, SI) and the topography of the SOZ (based on the Epileptogenicity Index, EI) in patients having focal neocortical epilepsies. Thirty-one patients were studied. A total of 539 brain regions were quantified in term of both spike generation (SI) and seizure initiation (EI).
  
  
  RESULTS
  We found a 56% (18/32) rate of agreement between maximal EI and maximal SI values. When considering separately patients with focal cortical dysplasia (FCD), the proportion of patients with good concordance was ∼75% (15/20), whereas it was only 33% (4/12) in the non FCD group.
  
  
  CONCLUSIONS
  Our results show that a significant part of patients have some dissociation between regions showing pronounced spiking activity and those showing high epileptogenicity. e is clinically important.
  
  
  CONCLUSIONS
  For patients with these dissociations, other markers than spiking frequency remain to be investigated. In the FCD group, the good concordance between SI and EI confirms that the mapping of the irritative zone is clinically important.
authors.affiliation: CHU Timone, Service de Neurophysiologie Clinique, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France; INSERM, UMR1106, Marseille F-13005, France; Aix Marseille Université, Institut de Neurosciences des Systèmes Marseille, F-13005, France. Electronic address: fabrice.bartolomei@ap-hm.fr.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bartolomei
authors.affiliation: CHU Timone, Service de Neurophysiologie Clinique, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France; INSERM, UMR1106, Marseille F-13005, France; Aix Marseille Université, Institut de Neurosciences des Systèmes Marseille, F-13005, France.
authors.forename: Agnes
authors.initials: A
authors.lastname: Trébuchon
authors.affiliation: CHU Timone, Service de Neurophysiologie Clinique, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France; INSERM, UMR1106, Marseille F-13005, France; Aix Marseille Université, Institut de Neurosciences des Systèmes Marseille, F-13005, France.
authors.forename: Francesca
authors.initials: F
authors.lastname: Bonini
authors.affiliation: CHU Timone, Service de Neurophysiologie Clinique, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France; INSERM, UMR1106, Marseille F-13005, France; Aix Marseille Université, Institut de Neurosciences des Systèmes Marseille, F-13005, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Lambert
authors.affiliation: CHU Timone, Service de Neurophysiologie Clinique, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France; INSERM, UMR1106, Marseille F-13005, France; Aix Marseille Université, Institut de Neurosciences des Systèmes Marseille, F-13005, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Gavaret
authors.affiliation: INSERM, UMR1106, Marseille F-13005, France; Aix Marseille Université, Institut de Neurosciences des Systèmes Marseille, F-13005, France.
authors.forename: Marmaduke
authors.initials: M
authors.lastname: Woodman
authors.affiliation: INSERM, UMR1106, Marseille F-13005, France; Aix Marseille Université, Institut de Neurosciences des Systèmes Marseille, F-13005, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Giusiano
authors.affiliation: INSERM, U1099, Université Rennes 1, Rennes, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Wendling
authors.affiliation: CHU Timone, Service de Neurophysiologie Clinique, Assistance Publique des Hôpitaux de Marseille, Marseille F-13005, France; INSERM, UMR1106, Marseille F-13005, France; Aix Marseille Université, Institut de Neurosciences des Systèmes Marseille, F-13005, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Bénar
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004569:Electroencephalography / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D054220:Malformations of Cortical Development / Q000175:diagnosis* / Q000503:physiopathology*; D008875:Middle Aged; D012640:Seizures / Q000175:diagnosis* / Q000503:physiopathology*; D055815:Young Adult
keywords: Focal cortical dysplasia; Focal epilepsy; SEEG; Seizures; Spikes