title: Significance of Very-High-Frequency Oscillations (Over 1,000Hz) in Epilepsy.
abstract: OBJECTIVE
  We previously reported ictal very-high-frequency oscillations (VHFO) of 1,000 to 2,500Hz recorded by subdural macroelectrodes using a 10-kHz sampling rate. The purpose of this study was to clarify the clinical significance of ictal VHFO in neocortical epilepsy.
  
  
  METHODS
  This study included 13 patients with neocortical epilepsy who underwent subdural electrode implantation and had at least 1 seizure recorded at a 10-kHz sampling rate and were followed for more than 2 years postoperatively. Extent of resection was determined considering the seizure onset zone (SOZ) and irritative zone, structural lesion, and functional areas. Areas showing VHFO and those with HFO were not taken into consideration. The presence or absence of VHFO (>1,000 Hz), HFO (200-1,000Hz) and SOZ, and completeness of resection of these areas were compared with postoperative seizure outcome.
  
  
  RESULTS
  Seven patients had favorable (Engel class Ia) and 6 had unfavorable outcomes (other classes). VHFO was recorded in 6 of 7 patients with a favorable outcome. On the contrary, VHFO was recorded in only 1 of 6 patients with unfavorable outcome. The presence of VHFO was significantly associated with favorable outcome. VHFO was recorded on a limited number of electrodes, and VHFO-generating areas were resected completely, whereas HFO-generating areas and/or SOZ were not always resected completely in both favorable and unfavorable outcome groups.
  
  
  CONCLUSIONS
  The presence of ictal VHFO may be predictive of favorable outcome. Ictal VHFO may be a more specific marker than ictal HFO or SOZ for identifying the core of epileptogenic zone.
authors.affiliation: National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan.
authors.forename: Naotaka
authors.initials: N
authors.lastname: Usui
authors.affiliation: National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan.
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Terada
authors.affiliation: National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Baba
authors.affiliation: National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Matsuda
authors.affiliation: National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Usui
authors.affiliation: National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan.
authors.forename: Takayasu
authors.initials: T
authors.lastname: Tottori
authors.affiliation: National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan.
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Mihara
authors.affiliation: National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan.
authors.forename: Yushi
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D000293:Adolescent; D000328:Adult; D058256:Brain Waves / Q000502:physiology*; D002648:Child; D004567:Electrodes, Implanted; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000503:physiopathology / Q000601:surgery; D004827:Epilepsy / Q000503:physiopathology / Q000601:surgery; D017034:Epilepsy, Frontal Lobe / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019579:Neocortex / Q000503:physiopathology* / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult