title: Intracranial video-EEG monitoring in presurgical evaluation of patients with refractory epilepsy.
abstract: OBJECTIVE
  Reviewing our experience in intracranial video-EEG monitoring in the presurgical evaluation of patients with refractory epilepsy.
  
  
  METHODS
  We report on 62 out of 202 (31%) patients with refractory epilepsy, who underwent a long term video-EEG monitoring (LTM). The epileptogenic zone (EZ) was localised either based on the results of LTM or after intracranial EEG recordings from depth, subdural or foramen ovale electrodes. The decision on the location of the electrodes was based upon semiology of the seizures, EEG findings and the lesions visualised in MRI brain scan. Intraoperative corticography was carried out before and right after the resection of the seizure onset zone.
  
  
  RESULTS
  The video-EEG monitoring could localise EZ in 43 (69%) cases based. The remaining patients underwent invasive diagnostics: 10 (53%) had intracerebral depth electrodes, 6 (31%) depth and subdural and 3 (16%) foramen ovale electrodes. Intracranial video EEG recordings showed seizure focus in all the patients. Ten of them had EZ in mesial temporal structures, 4 in accessory motor area, 3 at the base of the frontal lobe and 2 in parietal lobe. There was one case of an asymptomatic intracerebral haematoma at the electrode. All patients were subsequently operated on. In 15 (79%) cases the seizures subsided (follow-up from 2 to 5 years), in 4 (21%) they decreased.
  
  
  CONCLUSIONS
  The intracranial EEG is required in all patients with normal MRI (so-called nonlesional cases) in whom EZ is suspected to be located in the hippocampus, insula or in the basal parts of the frontal lobe.
authors.affiliation: Department of Neurosurgery and Oncology of Central Nervous System, Barlicki University Hospital, Medical University of Lodz, Lodz, Poland.
authors.forename: Marlena
authors.initials: M
authors.lastname: Hupalo
authors.affiliation: Department of Neurosurgery and Oncology of Central Nervous System, Barlicki University Hospital, Medical University of Lodz, Lodz, Poland.
authors.forename: Rafal
authors.initials: R
authors.lastname: Wojcik
authors.affiliation: Department of Neurosurgery and Oncology of Central Nervous System, Barlicki University Hospital, Medical University of Lodz, Lodz, Poland. Electronic address: dariusz.jaskolski@umed.lodz.pl.
authors.forename: Dariusz J
authors.initials: DJ
authors.lastname: Jaskolski
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000295:instrumentation*; D002540:Cerebral Cortex / Q000503:physiopathology / Q000601:surgery; D004292:Dominance, Cerebral / Q000502:physiology; D000069279:Drug Resistant Epilepsy / Q000503:physiopathology* / Q000601:surgery*; D000069280:Electrocorticography / Q000295:instrumentation*; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000295:instrumentation*; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D011300:Preoperative Care; D014741:Video Recording / Q000295:instrumentation*; D055815:Young Adult
keywords: Depth electrodes; Electrocorticography; Presurgical evaluation; Refractory epilepsy; Streoelectroencephalography