title: Differences in brain morphological findings between narcolepsy with and without cataplexy.
abstract: OBJECTIVE
  Maps of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) obtained by diffusion tensor imaging (DTI) can detect microscopic axonal changes by estimating the diffusivity of water molecules using magnetic resonance imaging (MRI). We applied an MRI voxel-based statistical approach to FA and ADC maps to evaluate microstructural abnormalities in the brain in narcolepsy and to investigate differences between patients having narcolepsy with and without cataplexy.
  
  
  METHODS
  Twelve patients with drug-naive narcolepsy with cataplexy (NA/CA), 12 with drug-naive narcolepsy without cataplexy (NA w/o CA) and 12 age-matched healthy normal controls (NC) were enrolled. FA and ADC maps for these 3 groups were statistically compared by using voxel-based one-way ANOVA. In addition, we investigated the correlation between FA and ADC values and clinical variables in the patient groups.
  
  
  RESULTS
  Compared to the NC group, the NA/CA group showed higher ADC values in the left inferior frontal gyrus and left amygdala, and a lower ADC value in the left postcentral gyrus. The ADC value in the right inferior frontal gyrus and FA value in the right precuneus were higher for NA/CA group than for the NA w/o CA group. However, no significant differences were observed in FA and ADC values between the NA w/o CA and NC groups in any of the areas investigated. In addition, no correlation was found between the clinical variables and ADC and FA values of any brain areas in these patient groups.
  
  
  CONCLUSIONS
  Several microstructural changes were noted in the inferior frontal gyrus and amygdala in the NA/CA but not in the NA w/o CA group. These findings suggest that these 2 narcolepsy conditions have different pathological mechanisms: narcolepsy without cataplexy form appears to be a potentially broader condition without any significant brain imaging differences from normal controls.
authors: Japan Somnology Center, Neuropsychiatric Research Institute, Tokyo, Japan ; Tokyo Medical University, Department of Somnology, Tokyo, Japan.
authors: Masaki
authors: M
authors: Nakamura
authors: Shingo
authors: S
authors: Nishida
authors: Kenichi
authors: K
authors: Hayashida
authors: Yoichiro
authors: Y
authors: Ueki
authors: Yves
authors: Y
authors: Dauvilliers
authors: Yuichi
authors: Y
authors: Inoue
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D002385:Cataplexy / Q000175:diagnosis / Q000209:etiology* / Q000473:pathology*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D009290:Narcolepsy / Q000150:complications* / Q000175:diagnosis / Q000473:pathology*; D055815:Young Adult