title: Co-occurrence of high-frequency oscillations and delayed responses evoked by intracranial electrical stimulation in stereo-EEG studies.
abstract: To perform a side-by-side comparison of two epileptogenicity biomarkers, high frequency oscillations (HFOs) and delayed responses (DRs), as a result of single-pulse electrical stimulation.
  
  
  
  We have recorded stimulation-evoked HFOs and DRs in 16 epileptic patients undergoing presurgical evaluation using the stereoelectroencephalographic method. To evaluate converging and complementary information provided by the biomarkers, we analyzed them individually and for logical "and"/"or" combinations between them. 3D maps of the biomarkers' distributions by recording location (inbound maps) and by stimulation location (outbound maps) were created to analyze their relationship with the epileptogenic structures.
  
  
  
  HFOs occur less frequently than DRs, by 18.7%, when counting by recording contacts, and more frequently, by 7.4%, when counting by stimulation contacts. 40.6% of the contacts exhibiting HFOs also exhibit DRs, and 44.1% of the contacts exhibiting DRs also exhibit HFOs. When combining biomarkers, there was a tradeoff between increased seizure onset zone (SOZ) sensitivity, from 21.3% to 73%, and decreased specificity, from 87.2% to 34.3%.
  
  
  
  There is a moderate similarity in the information provided by the DRs and HFOs.
  
  
  
  The biomarkers complement each other, but there is a tradeoff between different metrics for SOZ localization.
authors.affiliation: Physics Department, University of Bucharest, Str. Atomistilor 405, Magurele, Jud. Ilfov CP MG-11, Bucharest-Magurele, Romania; Epilepsy Center, University Hospital of Freiburg, Breisacher Str. 64, Freiburg, Germany.
authors.forename: Cristian
authors.initials: C
authors.lastname: Donos
authors.affiliation: Neurology Department, University Emergency Hospital, Splaiul Independentei 169, Bucharest, Romania; Neurology Department, Carol Davila University of Medicine and Pharmacy, Blvd. Eroii Sanitari 8, Bucharest, Romania.
authors.forename: Ioana
authors.initials: I
authors.lastname: Mîndruţă
authors.affiliation: Neurology Department, University Emergency Hospital, Splaiul Independentei 169, Bucharest, Romania.
authors.forename: Mihai Dragoş
authors.initials: MD
authors.lastname: Malîia
authors.affiliation: Department of Neurosurgery, Bagdasar-Arseni Emergency Hospital, Şos. Berceni 12, Bucharest, Romania.
authors.forename: Alin
authors.initials: A
authors.lastname: Raşină
authors.affiliation: Department of Neurosurgery, Bagdasar-Arseni Emergency Hospital, Şos. Berceni 12, Bucharest, Romania.
authors.forename: Jean
authors.initials: J
authors.lastname: Ciurea
authors.affiliation: Physics Department, University of Bucharest, Str. Atomistilor 405, Magurele, Jud. Ilfov CP MG-11, Bucharest-Magurele, Romania; FHC Inc, 1201 Main St, Bowdoin, ME, USA. Electronic address: andrei.barborica@fizica.unibuc.ro.
authors.forename: Andrei
authors.initials: A
authors.lastname: Barborica
mesh_terms: D000328:Adult; D058256:Brain Waves; D002648:Child; D046690:Deep Brain Stimulation; D000069279:Drug Resistant Epilepsy / Q000503:physiopathology*; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D011930:Reaction Time
keywords: Delayed responses; Drug resistant epilepsy; Epilepsy biomarkers; High-frequency oscillations; Seizure onset zone; Single pulse electrical stimulation