Neurological Effects of Exposure to Non-Hypoxic Hypobaria
Final rept. May 2011-Apr 2014
AIR FORCE MEDICAL WING (59TH) LACKLAND AFB TX WILFORD HALL AMBULATORY SURGICAL CENTER
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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 p0.020count p0.040 and U2P volume p0.001count p0.001 when compared to DOC, while PHY is not significantly different than U2P. Lower neurocognitive performance in the domains of reasoningcalculation p0.001, memory p0.036, information processing accuracy p0.032, and general cognitive functioning p0.004 was demonstrated in U2P compared to AFP. Lower neurocognitive test performance within the U2P shows lower performance in the domains of reasoningcalculation, 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.
- Medicine and Medical Research
- Stress Physiology