title: White and gray matter abnormalities in narcolepsy with cataplexy.
abstract: OBJECTIVE
  The authors applied diffusion-tensor imaging including measurements of mean diffusivity (MD), which is a parameter of brain tissue integrity, fractional anisotropy (FA), which is a parameter of neuronal fiber integrity, and voxel-based morphometry, which is a measure of gray and white matter volume, to detect brain tissue changes in patients with narcolepsy-cataplexy.
  
  
  METHODS
  N/A.
  
  
  METHODS
  Patients with narcolepsy-cataplexy (n = 16) and age-matched healthy control subjects (n = 12) were studied.
  
  
  METHODS
  Whole cerebral MD, FA measures, and the volumes of the gray and white matter compartments were analyzed using statistical parametric mapping.
  
  
  RESULTS
  Significant MD increases and concomitant FA decreases were localized in the fronto-orbital cortex (P < 0.001) and the anterior cingulate (FA, P < 0.001; MD, P = 0.03) in narcolepsy-cataplexy. Additional MD increases without FA changes were detected in the ventral tegmental area, the dorsal raphe nuclei (P < 0.001), and the hypothalamus (P < 0.01). FA signal decreases were observed in the white matter tracts of the inferior frontal and inferior temporal cortices of narcolepsy-cataplexy patients (P < 0.001). Brain volume loss was evident in focal areas of the inferior and superior temporal cortices (P < 0.001) and the cingulate (P = 0.038).
  
  
  CONCLUSIONS
  Areas of increased diffusivity in the hypothalamus appear consistent with hypocretinergic cell loss reported in narcolepsy-cataplexy. Signal abnormalities in the ventral tegmental area and the dorsal raphe nuclei correspond to major synaptic targets of hypocretin neurons that were associated with the regulation of the sleep-wake cycle. Brain tissue alterations identified in the frontal cortex and cingulate are crucial in the maintenance of attention and reward-dependent decision making, both known to be impaired in narcolepsy-cataplexy.
authors.affiliation: Department of Neurology, Innsbruck Medical University, Innsbruck, Austria. christoph.scherfler@i-med.ac.at
authors.forename: Christoph
authors.initials: C
authors.lastname: Scherfler
authors.forename: Birgit
authors.initials: B
authors.lastname: Frauscher
authors.forename: Michael
authors.initials: M
authors.lastname: Schocke
authors.forename: Michael
authors.initials: M
authors.lastname: Nocker
authors.forename: Viola
authors.initials: V
authors.lastname: Gschliesser
authors.forename: Laura
authors.initials: L
authors.lastname: Ehrmann
authors.forename: Markus
authors.initials: M
authors.lastname: Niederreiter
authors.forename: Regina
authors.initials: R
authors.lastname: Esterhammer
authors.forename: Klaus
authors.initials: K
authors.lastname: Seppi
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Brandauer
authors.forename: Werner
authors.initials: W
authors.lastname: Poewe
authors.forename: Birgit
authors.initials: B
authors.lastname: Högl
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002385:Cataplexy / Q000378:metabolism / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008032:Limbic System / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008636:Mesencephalon / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D009434:Neural Pathways / Q000473:pathology; D009929:Organ Size