McGuire Stephen A, Boone Goldie R E, Sherman Paul M, Tate David F, Wood Joe D, Patel Beenish, Eskandar George, Wijtenburg S Andrea, Rowland Laura M, Clarke Geoffrey D, Grogan Patrick M, Sladky John H, Kochunov Peter V
Department of Neurology, 59th Medical Wing, Joint Base San Antonio-Lackland, TX, USA.
Aerosp Med Hum Perform. 2016 Dec 1;87(12):983-988. doi: 10.3357/AMHP.4585.2016.
Nonhypoxic hypobaric (low atmospheric pressure) occupational exposure, such as experienced by U.S. Air Force U-2 pilots and safety personnel operating inside altitude chambers, is associated with increased subcortical white matter hyperintensity (WMH) burden. The pathophysiological mechanisms underlying this discrete WMH change remain unknown. The objectives of this study were to demonstrate that occupational exposure to nonhypoxic hypobaria is associated with altered white matter integrity as quantified by fractional anisotropy (FA) measured using diffusion tensor imaging and relate these findings to WMH burden and neurocognitive ability.
There were 102 U-2 pilots and 114 age- and gender-controlled, health-matched controls who underwent magnetic resonance imaging. All pilots performed neurocognitive assessment. Whole-brain and tract-wise average FA values were compared between pilots and controls, followed by comparison within pilots separated into high and low WMH burden groups. Neurocognitive measurements were used to help interpret group difference in FA values.
Pilots had significantly lower average FA values than controls (0.489/0.500, respectively). Regionally, pilots had higher FA values in the fronto-occipital tract where FA values positively correlated with visual-spatial performance scores (0.603/0.586, respectively). There was a trend for high burden pilots to have lower FA values than low burden pilots.
Nonhypoxic hypobaric exposure is associated with significantly lower average FA in young, healthy U-2 pilots. This suggests that recurrent hypobaric exposure causes diffuse axonal injury in addition to focal white matter changes.McGuire SA, Boone GRE, Sherman PM, Tate DF, Wood JD, Patel B, Eskandar G, Wijtenburg SA, Rowland LM, Clarke GD, Grogan PM, Sladky JH, Kochunov PV. White matter integrity in high-altitude pilots exposed to hypobaria. Aerosp Med Hum Perform. 2016; 87(12):983-988.
非低氧性低压（低气压）职业暴露，如美国空军U - 2飞行员以及在高海拔舱内工作的安全人员所经历的那样，与皮质下白质高信号（WMH）负担增加有关。这种离散的WMH变化背后的病理生理机制仍然未知。本研究的目的是证明职业性非低氧性低压暴露与白质完整性改变有关，这种改变通过使用扩散张量成像测量的分数各向异性（FA）来量化，并将这些发现与WMH负担和神经认知能力联系起来。
102名U - 2飞行员和114名年龄和性别匹配、健康状况相当的对照组人员接受了磁共振成像检查。所有飞行员都进行了神经认知评估。比较了飞行员和对照组之间全脑和逐束的平均FA值，然后在分为高WMH负担组和低WMH负担组的飞行员内部进行比较。神经认知测量用于帮助解释FA值的组间差异。
飞行员的平均FA值显著低于对照组（分别为0.489/0.500）。在区域上，飞行员在额枕束中的FA值较高，其中FA值与视觉空间性能得分呈正相关（分别为0.603/0.586）。高负担飞行员的FA值有低于低负担飞行员的趋势。
非低氧性低压暴露与年轻、健康的U - 2飞行员的平均FA显著降低有关。这表明反复的低压暴露除了导致局灶性白质变化外，还会引起弥漫性轴索损伤。
麦圭尔SA，布恩GRE，谢尔曼PM，泰特DF，伍德JD，帕特尔B，埃斯坎达尔G，维滕堡SA，罗兰LM，克拉克GD，格罗根PM，斯拉德基JH，科丘诺夫PV。暴露于低压环境的高海拔飞行员的白质完整性。航空航天医学与人类表现。2016；87(12):983 - 988。
