title: Quantitative EEG in acute mountain sickness.
abstract: OBJECTIVE
  To investigate if the EEG response at moderate altitude may predict a person's tolerance to acute mountain sickness (AMS).
  
  
  METHODS
  Frequency analysis (QEEG) of tape-recorded ambulatory EEG was performed in 6 climbers during a mountaineering expedition to 7546 m above sea level. The QEEG response in climbers, measured at sea level, at 4500 m, and at 1800 m 1-4 days after maximal altitude exposure, was compared to the change observed during consecutive sea level recordings in 10 control subjects.
  
  
  RESULTS
  Three climbers experienced slight (grade 1) AMS symptoms both at 4500 m and at maximal altitude exposure (Group 1). Three other climbers (Group 2) had no symptoms at 4500 m, but they developed AMS (grades 1, 2, or 3) at maximal altitude. Alpha amplitudes were higher at 4500 m in group 1 climbers, while it was lower in group 2 climbers compared to the sea level recording. Significant time x group interactions in ANOVA were found for delta (P = 0.005), theta (P = 0.001) and alpha (P = 0.001) amplitude, indicating that QEEG amplitudes decreased significantly at high altitude in group 2 climbers.
  
  
  CONCLUSIONS
  The QEEG response to moderate hypobaric hypoxia is not uniform, but the direction of QEEG amplitude change, particularly in the alpha band, may possibly predict the risk of developing AMS.
authors.affiliation: Department of Neurology, University Hospital of Trondheim, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Sand
authors.forename: O
authors.initials: O
authors.lastname: Nygaard
mesh_terms: D000208:Acute Disease; D000328:Adult; D000532:Altitude Sickness / Q000503:physiopathology*; D000704:Analysis of Variance; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D018570:Risk Assessment