INTRODUCTION: Recently, portable dry electroencephalographs (dry-EEGs) have indexed cognitive workload, fatigue, and drowsiness in operational environments. Using this technology this project assessed whether significant changes in brainwave frequency power occurred in response to hypoxic exposures as experienced in military aviation.METHODS: There were 60 (30 women, 30 men) student Naval Aviators or Flight Officers who were exposed to an intense (acute) high-altitude (25,000 ft) normobaric hypoxic exposure, and 20 min later, more gradual (insidious) normobaric hypoxic exposure up to 20,000 ft while flying a fixed-wing flight simulation and monitored with a dry-EEG system. Using MATLAB, EEG frequencies and power were quantified and analyzed. Cognitive performance was also assessed with a cognitive task validated under hypoxia. Normobaric hypoxia and O2 saturation (Spo2) were produced and monitored using the Reduced Oxygen Breathing Device (ROBD2).RESULTS: Significant Spo2 decreases were recorded at acute 25K and insidious 20K simulated altitudes. Significant power decreases were recorded in all frequencies (alpha, beta, gamma, and theta) and all channels with acute 25K exposures. Gamma, beta, and theta frequency power were significantly decreased with insidious 20K exposures at most of the channels. The frequency power decreases corresponded to significant decreases in cognitive performance and flight performance. Most importantly, frequency power suppressions occurred despite 42% of the volunteers not perceiving they were hypoxic in the acute phase, nor 20% in the insidious phase.DISCUSSION: Results suggest EEG suppression during acute/insidious hypoxia can index performance decrements. These findings have promising implications in the development of biosensors that mitigate potential in-flight hypoxic physiological episodes.Rice GM, Snider D, Drollinger S, Greil C, Bogni F, Phillips J, Raj A, Marco K, Linnville S. Dry-EEG manifestations of acute and insidious hypoxia during simulated flight. Aerosp Med Hum Perform. 2019; 90(2):92–100.

These results imply that ergonomic stressors that adversely impact lumbar symmetry may be a predominant factor in LBP during flight. Significant prevalence rates may persist in the absence of design enhancements that mitigate these stressors. Height was a significant predictor for in-flight LBP among U.S. Navy helicopter pilots studied and BMI, TFHs, and airframe were not. For every 1" increase among male pilot height values, the odds of experiencing significant LBP in flight increased by 9.3%, with those equal/taller than median (71 in.) having over twice the odds compared with those shorter.

Fexofenadine is comparable to placebo in its effect on the cognitive skills important for piloting an aircraft, while cetirizine impairs cognition and may affect piloting ability.

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These results suggest the use of wearable accelerometers is a valid means of detecting G forces during high performance aircraft flight. Future studies using this surrogate method of detecting accelerative forces combined with physiological information may yield valuable in-flight normative data that heretofore has been technically difficult to obtain and hence holds the promise of opening the door for a new golden age of aeromedical research.