title: Intracerebrally recorded high frequency oscillations: simple visual assessment versus automated detection.
abstract: OBJECTIVE
  We compared the possible contribution (in the detection of seizure onset zone - SOZ) of simple visual assessment of intracerebrally recorded high-frequency oscillations (HFO) with standard automated detection.
  
  
  METHODS
  We analyzed stereo-EEG (SEEG) recordings from 20 patients with medically intractable partial seizures (10 temporal/10 extratemporal). Independently using simple visual assessment and automated detection of HFO, we identified the depth electrode contacts with maximum occurrences of ripples (R) and fast ripples (FR). The SOZ was determined by independent visual identification in standard SEEG recordings, and the congruence of results from visual versus automated HFO detection was compared.
  
  
  RESULTS
  Automated detection of HFO correctly identified the SOZ in 14 (R)/10 (FR) out of 20 subjects; a simple visual assessment of SEEG recordings in the appropriate frequency ranges correctly identified the SOZ in 13 (R)/9 (FR) subjects.
  
  
  CONCLUSIONS
  Simple visual assessment of SEEG traces and standard automated detection of HFO seem to contribute comparably to the identification of the SOZ in patients with focal epilepsies. When using macroelectrodes in neocortical extratemporal epilepsies, the SOZ might be better determined by the ripple range.
  
  
  CONCLUSIONS
  Standard automated detection of HFO enables the evaluation of HFO characteristics in whole data. This detection allows general purpose and objective evaluation, without any bias from the neurophysiologist's experiences and practice.
authors.affiliation: Brno Epilepsy Center, Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Pail
authors.forename: Josef
authors.initials: J
authors.lastname: Halámek
authors.forename: Pavel
authors.initials: P
authors.lastname: Daniel
authors.forename: Robert
authors.initials: R
authors.lastname: Kuba
authors.forename: Ivana
authors.initials: I
authors.lastname: Tyrlíková
authors.forename: Jan
authors.initials: J
authors.lastname: Chrastina
authors.forename: Pavel
authors.initials: P
authors.lastname: Jurák
authors.forename: Ivan
authors.initials: I
authors.lastname: Rektor
authors.forename: Milan
authors.initials: M
authors.lastname: Brázdil
mesh_terms: D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex; D003626:Data Display; D004566:Electrodes; D004569:Electroencephalography / Q000295:instrumentation / Q000379:methods*; D004828:Epilepsies, Partial / Q000175:diagnosis*; D005260:Female; D006624:Hippocampus; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012640:Seizures / Q000175:diagnosis; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult
keywords: Epileptogenic zone; Extratemporal lobe epilepsy; Fast ripples; High frequency oscillations; Ripples; Seizure onset zone; Spikes; Temporal lobe epilepsy