Subtle Cognitive Effects of Moderate Hypoxia

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Subtle Cognitive Effects of Moderate Hypoxia

Hewett, Kate J.
Curry, Ian P.
Rath, Edna
Collins, Stephanie M.

USAARL 2009-17

Increasing worldwide concern over the effects of moderate altitude exposure on aircrew performance in unpressurized aircraft recently prompted efforts to formulate international standards for the use of supplementary oxygen. The purpose of this study was to assess the impact of low to moderate levels of hypoxic hypoxia on the performance of aircrew personnel. Fifty subjects were exposed in a randomized controlled fashion to 45-min exposures at each altitude (sea level, 8000, 10,000, 12,000 and 14,000 ft) simulated by the ROBD. During the latter part of the exposure the subjects completed the CogScreen®-HE to measure their cognitive performance. Saturation of Peripheral Oxygen (SpO2) analysis showed that although the subjects did become hypoxic (p<001), there was not statistically significant change in reaction time (p=.781), accuracy (p=.152), or throughout (p=.967) with
increasing altitude. The results indicate that healthy individuals aged 19 to 45 years do not experience significant cognitive deficit, as measured by the CogScreen®-HE, when exposed to moderate levels of hypoxia for exposure times of 45 min at various altitudes.