title: Early EEG improvement after ketogenic diet initiation.
abstract: OBJECTIVE
  This study examines electroencephalographic (EEG) changes in children with medication resistant epilepsy treated with the ketogenic diet (KD).
  
  
  METHODS
  Routine EEGs were obtained prior to KD initiation, then one month and three months later. Changes in EEG background slowing and frequency of interictal epileptiform discharges (IEDs) were evaluated using power spectrum analysis and manual determination of spike index. KD responders were compared to non-responders to determine if baseline or early EEG characteristics predicted treatment response (>50% seizure reduction) at three months.
  
  
  RESULTS
  Thirty-seven patients were evaluated. No differences in baseline EEG features were found between responder groups. Frequency of IEDs declined in 65% of patients as early as one month, by a median of 13.6% (IQR 2-33). Those with a ten percent or greater improvement in IED frequency at one month were greater than six times more likely to be KD responders (OR 6.5 95% CI 0.85-75 p=0.03). Qualitative and quantitative measures of EEG background slowing improved in the whole cohort, but did not predict responder status.
  
  
  CONCLUSIONS
  Baseline predictors of KD response remain elusive. Most patients experienced a reduction in IEDs and improvement in EEG background slowing after KD initiation. Reduction of IEDs at one month strongly predicted KD responder status at three months.
authors.affiliation: Department of Neurology and Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA. kesslers@email.chop.edu
authors.forename: Sudha Kilaru
authors.initials: SK
authors.lastname: Kessler
authors.forename: Paul R
authors.initials: PR
authors.lastname: Gallagher
authors.forename: Renée A
authors.initials: RA
authors.lastname: Shellhaas
authors.forename: Robert R
authors.initials: RR
authors.lastname: Clancy
authors.forename: A G Christina
authors.initials: AG
authors.lastname: Bergqvist
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D055423:Diet, Ketogenic / Q000379:methods*; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy / Q000175:diagnosis / Q000178:diet therapy*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D018709:Statistics, Nonparametric