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Mechanisms of Memory Dysfunction during High Altitude Hypoxia Training in Military Aircrew

Published online by Cambridge University Press:  07 December 2016

Daniel A. Nation*
Affiliation:
Department of Psychology, University of Southern California, Los Angeles, California
Mark W. Bondi
Affiliation:
Veterans Affairs San Diego Healthcare System, San Diego, California Department of Psychiatry, University of California at San Diego, La Jolla, California
Ellis Gayles
Affiliation:
United States Navy, Marine Corps Air Station Miramar, San Diego, California
Dean C. Delis
Affiliation:
Department of Psychiatry, University of California at San Diego, La Jolla, California
*
Correspondence and reprint requests to: Daniel A. Nation, Department of Psychology, University of Southern California, 3620 South McClintock Avenue, Los Angeles, CA 90089-1061. E-mail: [email protected]

Abstract

Objectives: Cognitive dysfunction from high altitude exposure is a major cause of civilian and military air disasters. Pilot training improves recognition of the early symptoms of altitude exposure so that countermeasures may be taken before loss of consciousness. Little is known regarding the nature of cognitive impairments manifesting within this critical window when life-saving measures may still be taken. Prior studies evaluating cognition during high altitude simulation have predominantly focused on measures of reaction time and other basic attention or motor processes. Memory encoding, retention, and retrieval represent critical cognitive functions that may be vulnerable to acute hypoxic/ischemic events and could play a major role in survival of air emergencies, yet these processes have not been studied in the context of high altitude simulation training. Methods: In a series of experiments, military aircrew underwent neuropsychological testing before, during, and after brief (15 min) exposure to high altitude simulation (20,000 ft) in a pressure-controlled chamber. Results: Acute exposure to high altitude simulation caused rapid impairment in learning and memory with relative preservation of basic visual and auditory attention. Memory dysfunction was predominantly characterized by deficiencies in memory encoding, as memory for information learned during high altitude exposure did not improve after washout at sea level. Retrieval and retention of memories learned shortly before altitude exposure were also impaired, suggesting further impairment in memory retention. Conclusions: Deficits in memory encoding and retention are rapidly induced upon exposure to high altitude, an effect that could impact life-saving situational awareness and response. (JINS, 2017, 23, 1–10)

Type
Research Articles
Copyright
Copyright © The International Neuropsychological Society 2016 

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References

Asmaro, D., Mayall, J., & Ferguson, S. (2013). Cognition at altitude: Impairment in executive and memory processes under hypoxic conditions. Aviation, Space, and Environmental Medicine, 84(11), 11591165.Google Scholar
Australian Transport Safety Bureau. (2014). MH370 - Definition of underwater search areas. Retrieved from https://www.atsb.gov.au/newsroom/news-items/2015/mh370-definition-of-underwater-search-areas.aspx.Google Scholar
Cable, G.G. (2003). In-flight hypoxia incidents in military aircraft: Causes and implications for training. Aviation, Space, and Environmental Medicine, 74(2), 169172.Google Scholar
Cavaletti, G., Moroni, R., Garavaglia, P., & Tredici, G. (1987). Brain damage after high-altitude climbs without oxygen. Lancet, 1(8524), 101.Google Scholar
Crow, T.J., & Kelman, G.R. (1971). Effect of mild acute hypoxia on human short-term memory. British Journal of Anaesthesia, 43(6), 548552.CrossRefGoogle ScholarPubMed
Crow, T.J., & Kelman, G.R. (1973). Psychological effects of mild acute hypoxia. British Journal of Anaesthesia, 45(4), 335337.CrossRefGoogle ScholarPubMed
Denison, D.M., Ledwith, F., & Poulton, E.C. (1966). Complex reaction times at simulated cabin altitudes of 5,000 feet and 8,000 feet. Aerospace Medicine, 37(10), 10101013.Google Scholar
Fowler, B., Paul, M., Porlier, G., Elcombe, D.D., & Taylor, M. (1985). A re-evaluation of the minimum altitude at which hypoxic performance decrements can be detected. Ergonomics, 28(5), 781791. doi: 10.1080/00140138508963198 Google Scholar
Frisby, J.P., Barrett, R.F., & Thornton, J.A. (1973). Effect of mild acute hypoxia on a decision-making task. Aerospace Medicine, 44(5), 523526.Google Scholar
Gold, R.E., & Kulak, L.L. (1972). Effect of hypoxia on aircraft pilot performance. Aerospace Medicine, 43(2), 180183.Google Scholar
Gozal, D., Daniel, J.M., & Dohanich, G.P. (2001). Behavioral and anatomical correlates of chronic episodic hypoxia during sleep in the rat. Journal of Neuroscience, 21(7), 24422450.Google Scholar
Green, R.G., & Morgan, D.R. (1985). The effects of mild hypoxia on a logical reasoning task. Aviation, Space, and Environmental Medicine, 56(10), 10041008.Google Scholar
Island, R., & Fraley, E. (1993). Analysis of USAF hypoxia incidents January 1976 through March 1990. Paper presented at the Proceedings of the 31st Annual SAFE Symposium, Creswell, OR.Google Scholar
Kalaria, R., Ferrer, I., & Love, S. (2015). Vascular disease, hypoxia and related conditions. In S. Love, A. Perry, J. Ironside, & H. Budka (Eds.), Greenfield’s neuropathology (9th ed.). New York: CRC Press.Google Scholar
Kelman, G.R., & Crow, T.J. (1969). Impairment of mental performance at a simulated altitude of 8,000 feet. Aerospace Medicine, 40(9), 981982.Google Scholar
Kida, M., & Imai, A. (1993). Cognitive performance and event-related brain potentials under simulated high altitudes. Journal of Applied Physiology, 74(4), 17351741.CrossRefGoogle ScholarPubMed
Kramer, A.F., Coyne, J.T., & Strayer, D.L. (1993). Cognitive function at high altitude. Human Factors, 35(2), 329344.Google Scholar
Malle, C., Quinette, P., Laisney, M., Bourrilhon, C., Boissin, J., Desgranges, B., & Pierard, C. (2013). Working memory impairment in pilots exposed to acute hypobaric hypoxia. Aviation, Space, and Environmental Medicine, 84(8), 773779.Google Scholar
McCarthy, D., Corban, R., Legg, S., & Faris, J. (1995). Effects of mild hypoxia on perceptual-motor performance: A signal-detection approach. Ergonomics, 38(10), 19791992.Google Scholar
Newman, D.G. (2000). Runaway plane. Flight Safety Australia, March–April: 42–44.Google Scholar
Paul, M.A., & Fraser, W.D. (1994). Performance during mild acute hypoxia. Aviation, Space, and Environmental Medicine, 65(10 Pt 1), 891899.Google Scholar
Pavlicek, V., Schirlo, C., Nebel, A., Regard, M., Koller, E.A., & Brugger, P. (2005). Cognitive and emotional processing at high altitude. Aviation, Space, and Environmental Medicine, 76(1), 2833.Google Scholar
Petrassi, F.A., Hodkinson, P.D., Walters, P.L., & Gaydos, S.J. (2012). Hypoxic hypoxia at moderate altitudes: Review of the state of the science. Aviation, Space, and Environmental Medicine, 83(10), 975984.Google Scholar
Turner, C.E., Barker-Collo, S.L., Connell, C.J., & Gant, N. (2015). Acute hypoxic gas breathing severely impairs cognition and task learning in humans. Physiology and Behavior, 142, 104110. doi: 10.1016/j.physbeh.2015.02.006 Google Scholar
Vargha-Khadem, F., Gadian, D.G., Watkins, K.E., Connelly, A., Van Paesschen, W., & Mishkin, M. (1997). Differential effects of early hippocampal pathology on episodic and semantic memory. Science, 277(5324), 376380.CrossRefGoogle ScholarPubMed
Virues-Ortega, J., Buela-Casal, G., Garrido, E., & Alcazar, B. (2004). Neuropsychological functioning associated with high-altitude exposure. Neuropsychology Review, 14(4), 197224.Google Scholar