title: Factors underlying scalp-EEG interictal epileptiform discharges in intractable frontal lobe epilepsy.
abstract: OBJECTIVE
  Scalp-EEG interictal epileptiform discharges (IEDs) may be less predictive of the outcome of frontal lobe epilepsy surgery than of temporal lobe epilepsy surgery. We identified factors associated with the location of scalp-EEG IEDs in intractable frontal lobe epilepsy.
  
  
  METHODS
  Ten factors were assessed in a retrospective review of 53 patients with either concordant (frontal lobe seizure focus) or discordant (generalized or outside frontal seizure focus) IED or both, who had excellent surgical outcomes. The Fisher exact test and the Wilcoxon rank sum test determined statistically significant associations.
  
  
  RESULTS
  Thirty-six patients (68%) had concordant IED, 24 (45%) discordant IED, and 17 (32%) both. Younger age at onset was significantly associated with discordant IED (mean, 7.5 years versus 17 years for patients without discordant IED; P < 0.01), whereas duration of epilepsy was not. Seizure foci at the frontal convexity were associated with concordant IED. About 72% of patients with a convexity seizure focus had concordant IED, compared with only 33% of patients with mesial frontal foci having concordant IED (P = 0.06).
  
  
  CONCLUSIONS
  Early seizure onset in intractable frontal lobe epilepsy is associated with IEDs discordant with seizure focus. Frontal convexity seizure foci are more likely than mesial frontal seizure foci to be associated with concordant discharges.
authors.affiliation: Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
authors.forename: Lata
authors.initials: L
authors.lastname: Vadlamudi
authors.forename: Elson L
authors.initials: EL
authors.lastname: So
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Worrell
authors.forename: Russell K
authors.initials: RK
authors.lastname: Mosewich
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Cascino
authors.forename: Fredric B
authors.initials: FB
authors.lastname: Meyer
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Lesnick
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003937:Diagnosis, Differential; D004569:Electroencephalography; D017034:Epilepsy, Frontal Lobe / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D019635:Neurosurgical Procedures / Q000379:methods; D012189:Retrospective Studies; D012535:Scalp; D012720:Severity of Illness Index; D020535:Video-Assisted Surgery