Neurological Effects of Exposure to Non-Hypoxic Hypobaria

Abstract

The objective of this study was to investigate the neurological effects of exposure to non-hypoxic hypobaria following an outbreak of neurological decompression sickness in U-2 pilots. Eighty-three altitude chamber personnel (PHY), 105 U-2 pilots (U2P), and 162 age and medically matched doctorate degree controls (DOC) underwent high-resolution magnetic resonance imaging. Eighty-seven U-2 pilots underwent neurocognitive testing and were compared to 83 USAF pilot controls (AFP). White matter hyperintensities (WMH) are more prevalent in PHY (volume p=0.020/count p=0.040) and U2P (volume p<0.001/count p<0.001) when compared to DOC, while PHY is not significantly different than U2P. Lower neurocognitive performance in the domains of reasoning/calculation (p=0.001), memory (p=0.036), information processing accuracy (p=0.032), and general cognitive functioning (p=0.004) was demonstrated in U2P compared to AFP. Lower neurocognitive test performance within the U2P shows lower performance in the domains of reasoning/calculation, memory, general cognitive functioning, and general cognitive proficiency in U2P with higher WMH burden compared to U2P with lower WMH burden. This study provides strong evidence that non-hypoxic hypobaric exposure in U2P and PHY is associated with subcortical WMH in a young, healthy population lacking other risk factors for WMH and adds this occupational exposure to other environmentally related potential causes of WMH. This study also demonstrates measurable lower neurocognitive test performance in otherwise highly functioning U2P compared to AFP and furthermore demonstrates higher WMH burden is associated with lower neurocognitive test performance.

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Document Details

Document Type
Technical Report
Publication Date
Apr 16, 2014
Accession Number
ADA608671

Entities

People

  • Alan Flower
  • Gary Ford
  • Gerald York
  • Joe Wood Iii
  • John Sladky
  • Patrick Grogan
  • Paul Sherman
  • Roger Hesselbrock
  • Stephen A McGuire

Organizations

  • 59th Medical Wing

Tags

Communities of Interest

  • Biomedical

DTIC Thesaurus Topics

  • Accuracy
  • Air Force
  • Air Force Research Laboratories
  • Altitude
  • Altitude Chambers
  • Brain Injuries
  • Decompression Sickness
  • Diseases And Disorders
  • Health Services
  • High Resolution
  • Information Processing
  • Institutional Review Board
  • Magnetic Resonance
  • Magnetic Resonance Imaging
  • Medical Personnel
  • Risk Factors
  • Three Dimensional

Fields of Study

  • Medicine

Readers

  • Auditory Neuroscience/Auditory Physiology.
  • Psychometric Testing or Psychological Assessment.