title: An interictal EEG can predict the outcome of vagus nerve stimulation therapy for children with intractable epilepsy.
abstract: OBJECTIVE
  This study aimed to evaluate the long-term efficacy of vagus nerve stimulation (VNS) in children and adolescents with intractable epilepsy and identify predictive factors for responsiveness to VNS.
  
  
  METHODS
  Medical records of pediatric patients who underwent VNS implantation at two Korean tertiary centers were reviewed. At 0.5, 1, 3, and 5 years post-VNS implantation, the frequency of the most disabling seizures in each patient was assessed. Responders were defined as showing an overall 50 % reduction from baseline seizure frequency during follow-up. The clinical characteristics of responders and non-responders were compared.
  
  
  RESULTS
  Among 58 patients, approximately half (29/58) were responders. The mean age at implantation was 10.9 years (range, 2.7-20.9) and the mean follow-up duration after VNS implantation was 8.4 years (range, 1-15.5). At 0.5, 1, 3, and 5 years after implantation, 43.1, 50.0, 56.9, and 58.1 % of patients exhibited ≥50 % seizure frequency reduction disabling seizures. The patients with focal or multifocal epileptiform discharges were more likely to be responders than those with generalized epileptiform activities by video or conventional EEG at the time of VNS implantation (Pearson's and χ2test, p = 0.001). No other clinical variables were found to be associated with seizure outcomes. Wound infections caused VNS removal in two cases. All other adverse events, including cough and hoarseness, were tolerable.
  
  
  CONCLUSIONS
  VNS is a well-tolerated and effective adjuvant therapy in pediatric patients with intractable epilepsy. Notably, patients with focal epileptiform discharges alone rather than those with generalized epileptiform discharges maybe better candidates for VNS.
authors.affiliation: Department of Pediatrics, Asan Medical Center Children's Hospital, Ulsan University College of Medicine, 43 Olympic-ro, Songpa-gu, Seoul, 138-736, South Korea.
authors.forename: Min-Jee
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Asan Medical Center Children's Hospital, Ulsan University College of Medicine, 43 Olympic-ro, Songpa-gu, Seoul, 138-736, South Korea.
authors.forename: Mi-Sun
authors.initials: MS
authors.lastname: Yum
authors.affiliation: Department of Pediatrics, CHA Gangnam Medical Center, CHA University, Pocheon-si, South Korea.
authors.forename: Eun-Hee
authors.initials: EH
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Asan Medical Center Children's Hospital, Ulsan University College of Medicine, 43 Olympic-ro, Songpa-gu, Seoul, 138-736, South Korea.
authors.forename: Yun-Jeong
authors.initials: YJ
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Asan Medical Center Children's Hospital, Ulsan University College of Medicine, Seoul, South Korea.
authors.forename: Junkyo
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Asan Medical Center Children's Hospital, Ulsan University College of Medicine, Seoul, South Korea.
authors.forename: Seokho
authors.initials: S
authors.lastname: Hong
authors.affiliation: Department of Pediatrics, Sanggye Paik Hospital, Inje University College of Medicine, 1342 Dongil-ro, Nowon-gu, Seoul, 139-707, South Korea. sjyou@paik.ac.kr.
authors.forename: Su Jeong
authors.initials: SJ
authors.lastname: You
authors.affiliation: Department of Neurosurgery, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, South Korea.
authors.forename: Yong Soon
authors.initials: YS
authors.lastname: Hwang
authors.affiliation: Department of Pediatrics, Asan Medical Center Children's Hospital, Ulsan University College of Medicine, 43 Olympic-ro, Songpa-gu, Seoul, 138-736, South Korea. tsko@amc.seoul.kr.
authors.forename: Tae-Sung
authors.initials: TS
authors.lastname: Ko
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D000069279:Drug Resistant Epilepsy / Q000503:physiopathology* / Q000628:therapy*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D016896:Treatment Outcome; D055536:Vagus Nerve Stimulation / Q000379:methods*; D055815:Young Adult
keywords: Child; EEG; Epilepsy; Pediatric; Vagus nerve stimulation (VNS)