title: Asymmetrical generalized paroxysmal fast activities in children with intractable localization-related epilepsy.
abstract: BACKGROUND
  Generalized paroxysmal fast activity (GPFA) consists of burst of generalized rhythmic discharges; 100-200 μV; 1-9s; 8-26 Hz; with frontal predominance; appearing during NREM sleep. GPFA was originally described as an electrographic feature of Lennox-Gastaut Syndrome (LGS). We analyzed GPFA on scalp video EEG (VEEG) in children to evaluate that GPFA presents in patients with intractable localization-related epilepsy.
  
  
  METHODS
  We collected cases with GPFA with intractable localization-related epilepsy who underwent scalp VEEG, MRI, and magnetoencephalography (MEG) prior to intracranial video EEG (IVEEG) and surgical resection. We collected 50 epochs of GPFA per patient during the first night during scalp VEEG. We analyzed amplitude, duration and frequency of GPFA over the bilateral frontal region between surgical resection side with grid placement and non-resection side.
  
  
  RESULTS
  We identified 14 (14%) patients with GPFA on scalp VEEG. The mean amplitude ranged from 145 to 589 μV (mean 293 μV). The mean duration ranged from 1.18 to 2.31s (mean 1.6s). The mean frequencies ranged from 9.3 to 14.7 Hz (mean 11.1 Hz). The amplitude (307 ± 156 μV) and duration (1.62 ± 0.8s) of GPFAs in all the patients over the resection side were significantly higher than those (279 ± 141 μV, 1.58 ± 0.8s) of the non-resection side (p<0.001). All nine patients who showed significant duration differences between two hemispheres (p<0.05) had longer duration of GPFA over the resection side. Eight of 12 patients who showed significant amplitude differences between two hemispheres (p<0.05) had higher amplitude of GPFA over the resection side. Four of six patients who showed significant frequency differences between two hemispheres (p<0.05) had higher frequency of GPFA over the resection side. Nine (64%) patients became seizure free after surgical resection including multilobar resections in eight patients.
  
  
  CONCLUSIONS
  GPFA can exist in localization-related epilepsy with secondary bilateral synchrony. Although EEG shows GPFA on scalp VEEG, the precise localization of the epileptogenic zone using IVEEG could achieve the successful surgical resection.
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada; Department of Pediatric Neurology, Children's Medical Center, Tehran, Iran.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Mohammadi
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Tohru
authors.initials: T
authors.lastname: Okanishi
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Okanari
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Shiro
authors.initials: S
authors.lastname: Baba
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sumiyoshi
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Satoru
authors.initials: S
authors.lastname: Sakuma
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Ayako
authors.initials: A
authors.lastname: Ochi
authors.affiliation: Diagnostic Imaging, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Elysa
authors.initials: E
authors.lastname: Widjaja
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: Cristina Y
authors.initials: CY
authors.lastname: Go
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada.
authors.forename: O Carter
authors.initials: OC
authors.lastname: Snead
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada. Electronic address: hiroshi.otsubo@sickkids.ca.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Otsubo
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male
keywords: Amplitude; Asymmetry; Children; Cortico-thalamic epileptic network; Duration; Epilepsy surgery; Epileptogenic hemisphere; Generalized paroxysmal fast activity (GPFA); Intracranial video EEG; Localization-related epilepsy