title: Reduced default mode network connectivity in treatment-resistant idiopathic generalized epilepsy.
abstract: OBJECTIVE
  Idiopathic generalized epilepsy (IGE) resistant to treatment is common, but its neuronal correlates are not entirely understood. Therefore, the aim of this study was to examine resting-state default mode network (DMN) functional connectivity in patients with treatment-resistant IGE.
  
  
  METHODS
  Treatment resistance was defined as continuing seizures despite an adequate dose of valproic acid (valproate, VPA). Data from 60 epilepsy patients and 38 healthy controls who underwent simultaneous electroencephalography (EEG) and resting-state functional magnetic resonance imaging (fMRI) were included (EEG/fMRI). Independent component analysis (ICA) and dual regression were used to quantify DMN connectivity. Confirmatory analysis using seed-based voxel correlation was performed.
  
  
  RESULTS
  There was a significant reduction of DMN connectivity in patients with treatment-resistant epilepsy when compared to patients who were treatment responsive and healthy controls. Connectivity was negatively correlated with duration of epilepsy.
  
  
  CONCLUSIONS
  Our findings in this large sample of patients with IGE indicate the presence of reduced DMN connectivity in IGE and show that connectivity is further reduced in treatment-resistant epilepsy. DMN connectivity may be useful as a biomarker for treatment resistance.
authors.affiliation: Neuroscience Graduate Program, University of Cincinnati, Cincinnati, Ohio, USA. benjamin@benkay.net
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Kay
authors.forename: Mark W
authors.initials: MW
authors.lastname: DiFrancesco
authors.forename: Michael D
authors.initials: MD
authors.lastname: Privitera
authors.forename: Jean
authors.initials: J
authors.lastname: Gotman
authors.forename: Scott K
authors.initials: SK
authors.lastname: Holland
authors.forename: Jerzy P
authors.initials: JP
authors.lastname: Szaflarski
mesh_terms: D000293:Adolescent; D000328:Adult; D015536:Down-Regulation / Q000502:physiology; D004829:Epilepsy, Generalized / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology*; D011446:Prospective Studies; D017211:Treatment Failure; D016896:Treatment Outcome; D014635:Valproic Acid / Q000494:pharmacology / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D014635:Valproic Acid