Normobaric hypoxia (NH) and hypobaric hypoxia (HH) are both used to train aircraft pilots to recognize symptoms of hypoxia. NH (low oxygen concentration) training is often preferred because it is more cost effective, simpler, and safer than HH. It is unclear, however, whether NH is neurophysiologically equivalent to HH (high altitude). Previous studies have shown that neural oscillations, particularly those in the alpha band (8–12 Hz), are impacted by hypoxia. Attention tasks have been shown to reliably modulate alpha oscillations, although the neurophysiological impacts of hypoxia during cognitive processing remains poorly understood. To address this we investigated induced and evoked power alongside physiological data while participants performed an attention task during control (normobaric normoxia or NN), NH (fraction of inspired oxygen = 12.8%, partial pressure of inspired oxygen = 87.2 mmHg), and HH (3962 m, partial pressure of inspired oxygen = 87.2 mmHg) conditions inside a hypobaric chamber. No significant differences between NH and HH were found in oxygen saturation, end tidal gases, breathing rate, middle cerebral artery velocity and blood pressure. Induced alpha power was significantly decreased in NH and HH when compared to NN. Participants in the HH condition showed significantly increased induced lower-beta power and evoked higher-beta power, compared with the NH and NN conditions, indicating that NH and HH differ in their impact on neurophysiological activity supporting cognition. NH and HH were found not to be neurophysiologically equivalent as electroencephalography was able to differentiate NH from HH.

常压缺氧 (NH) 和低压缺氧 (HH) 均用于训练飞机飞行员识别缺氧症状。NH（低氧浓度）训练通常是首选，因为它比 HH 更具成本效益、更简单且更安全。然而，尚不清楚 NH 在神经生理学上是否等同于 HH（高海拔）。先前的研究表明，神经振荡，尤其是 α 波段（8-12 Hz）的神经振荡，会受到缺氧的影响。尽管认知过程中缺氧对神经生理学的影响仍知之甚少，但注意力任务已被证明可以可靠地调节阿尔法振荡。为了解决这个问题，我们在参与者在控制（常压常氧或 NN）、NH（吸入氧分数 = 12.8%，吸入氧分压 = 87.2 mmHg）和 HH（吸入氧分压 = 87.2 mmHg）和 HH（ 3962 m，吸入氧分压 = 87.2 mmHg）低压室内条件。NH 和 HH 之间的氧饱和度、潮气末气体、呼吸频率、大脑中动脉流速和血压没有显着差异。与 NN 相比，NH 和 HH 中的诱导 α 功率显着降低。与 NH 和 NN 条件相比，HH 条件下的参与者表现出显着增加的诱导较低 β 功率和诱发较高 β 功率，表明 NH 和 HH 对支持认知的神经生理活动的影响不同。NH 和 HH 被发现在神经生理学上并不等同，因为脑电图能够区分 NH 和 HH。