title: Prefrontal lactate predicts exercise-induced cognitive dysfunction in Gulf War Illness.
abstract: BACKGROUND
  25% to 30% of Veterans deployed to the 1990 to 1991 Persian Gulf War exhibit an idiopathic syndrome of chronic fatigue, exertional exhaustion, pain, hyperalgesia, cognitive and affective dysfunction known as Gulf War Illness (GWI).
  
  
  METHODS
  Gulf War veterans (n=15) and sedentary veteran and civilian controls (n=11) completed a 2-back working memory test in an fMRI before and after two bicycle exercise stress test. We performed single voxel (1)H MRS to evaluate brain metabolic differences in the left anterior cingulate cortex and the changes associated with exercise.
  
  
  RESULTS
  Eight GWI subjects increased their 2-back scores after exercise (labelled increasers) and seven GWI subjects decreased their 2-back scores after exercise (labelled decreasers). These phenotypic responses were absent for controls. Decreasers had significantly elevated prefrontal lactate levels compared to Increasers prior to completion of the exercise stress tests. Evaluation of prefrontal lactate levels prior to exercise demonstrated predictability (ROC analysis) of the two diametrically opposed subgroups.
  
  
  CONCLUSIONS
  Prefrontal lactate levels may be a potential biomarker for exercise-induced subgroups in GWI. The alterations in brain energetics may be in part responsible for a subgroup of GWI and underlie some of the symptoms present in the patient population.
authors.affiliation: Division of Rheumatology, Immunology and Allergy; Department of Medicine, Georgetown University Medical Center Room 3004F 3rd Floor PHC Building, 3800 Reservoir Road, NW, Washington, DC 20007, USA.
authors.forename: Rakib U
authors.initials: RU
authors.lastname: Rayhan
authors.forename: Megna P
authors.initials: MP
authors.lastname: Raksit
authors.forename: Christian R
authors.initials: CR
authors.lastname: Timbol
authors.forename: Oluwatoyin
authors.initials: O
authors.lastname: Adewuyi
authors.forename: John W
authors.initials: JW
authors.lastname: Vanmeter
authors.forename: James N
authors.initials: JN
authors.lastname: Baraniuk
keywords: Gulf War Illness (GWI); biomarker; exercise-induced cognitive dysfunction; pre-frontal lactate