title: Increased brain white matter axial diffusivity associated with fatigue, pain and hyperalgesia in Gulf War illness.
abstract: BACKGROUND
  Gulf War exposures in 1990 and 1991 have caused 25% to 30% of deployed personnel to develop a syndrome of chronic fatigue, pain, hyperalgesia, cognitive and affective dysfunction.
  
  
  METHODS
  Gulf War veterans (n = 31) and sedentary veteran and civilian controls (n = 20) completed fMRI scans for diffusion tensor imaging. A combination of dolorimetry, subjective reports of pain and fatigue were correlated to white matter diffusivity properties to identify tracts associated with symptom constructs.
  
  
  RESULTS
  Gulf War Illness subjects had significantly correlated fatigue, pain, hyperalgesia, and increased axial diffusivity in the right inferior fronto-occipital fasciculus. ROC generated thresholds and subsequent binary regression analysis predicted CMI classification based upon axial diffusivity in the right inferior fronto-occipital fasciculus. These correlates were absent for controls in dichotomous regression analysis.
  
  
  CONCLUSIONS
  The right inferior fronto-occipital fasciculus may be a potential biomarker for Gulf War Illness. This tract links cortical regions involved in fatigue, pain, emotional and reward processing, and the right ventral attention network in cognition. The axonal neuropathological mechanism(s) explaining increased axial diffusivity may account for the most prominent symptoms of Gulf War Illness.
authors.affiliation: Georgetown University Medical Center, Department of Medicine, Division of Rheumatology, Immunology and Allergy, Washington, DC, United States of America. rur@georgetown.edu
authors.forename: Rakib U
authors.initials: RU
authors.lastname: Rayhan
authors.forename: Benson W
authors.initials: BW
authors.lastname: Stevens
authors.forename: Christian R
authors.initials: CR
authors.lastname: Timbol
authors.forename: Oluwatoyin
authors.initials: O
authors.lastname: Adewuyi
authors.forename: Brian
authors.initials: B
authors.lastname: Walitt
authors.forename: John W
authors.initials: JW
authors.lastname: VanMeter
authors.forename: James N
authors.initials: JN
authors.lastname: Baraniuk
mesh_terms: D000328:Adult; D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D056324:Diffusion Tensor Imaging; D005221:Fatigue / Q000503:physiopathology; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology; D018923:Persian Gulf Syndrome / Q000473:pathology* / Q000503:physiopathology*; D014728:Veterans