title: Observations on the use of vagus nerve stimulation earlier in the course of pharmacoresistant epilepsy: patients with seizures for six years or less.
abstract: BACKGROUND
  This study retrospectively compared the effectiveness of vagus nerve stimulation (VNS) therapy among a constant cohort of patients in the patient outcome registry, which systematically monitors outcomes of patients receiving VNS therapy. Patients in the study had pharmacoresistant seizures for 6 years or less (early treatment group) or more than 6 years (late treatment group) before initiation of VNS therapy, and results are provided after both 3 and 12 months.
  
  
  RESULTS
  Of 405 patients, 51 were in the early and 354 in the late treatment groups. Median age at onset of seizures was 7 years in the early and 4.5 years in the late treatment group. Seizure reduction of 100% was reported in 7.8% (early) and 3.7% (late) patients at 3 months and 11.8% (early) and 4.5% (late) at 12 months (P = 0.033). Reductions in seizure frequency greater than or equal to 90% for early and late treatment groups were similar: 11.8% (early) and 11.0% (late) at 3 months and 23.5% (early) and 17.0% (late) at 12 months.
  
  
  CONCLUSIONS
  Patients treated earlier with VNS therapy were twice as likely to report no seizures as patients who had seizures for more than 6 years before they received VNS therapy. The effectiveness of VNS therapy should be assessed among other patients with pharmacoresistant seizures and lesser cumulative seizure loads.
authors.affiliation: Emory University School of Medicine, Atlanta, GA, USA. sandra_helmers@emory.org
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Helmers
authors.forename: David A
authors.initials: DA
authors.lastname: Griesemer
authors.forename: J Christine
authors.initials: JC
authors.lastname: Dean
authors.forename: Jorge D
authors.initials: JD
authors.lastname: Sanchez
authors.forename: Douglas
authors.initials: D
authors.lastname: Labar
authors.forename: Jerome V
authors.initials: JV
authors.lastname: Murphy
authors.forename: David
authors.initials: D
authors.lastname: Bettis
authors.forename: Yong D
authors.initials: YD
authors.lastname: Park
authors.forename: Robert M
authors.initials: RM
authors.lastname: Shuman
authors.forename: George L
authors.initials: GL
authors.lastname: Morris
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000927:Anticonvulsants / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004599:Electric Stimulation Therapy / Q000706:statistics & numerical data*; D004827:Epilepsy / Q000503:physiopathology* / Q000628:therapy*; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D012042:Registries / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D014630:Vagus Nerve / Q000503:physiopathology*
chemical_list: D000927:Anticonvulsants