Mental Performance in Chronic Anoxia

Greene, Raymond

doi:10.1136/bmj.1.5026.1028

Cited by 14 publications

(10 citation statements)

References 3 publications

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“…Altitude related medical problems are gaining importance and attention as an increasing number of trekkers and recreational climbers attempt ascents to very high (3500m to 5500m) or extreme altitudes (>5500m) [ 1 ]. The possibility of long-term cerebral sequelae from exposure to severe hypobaric hypoxia has been a topic of controversy for decades [ 2 – 4 ]. Structural cerebral changes detected by magnetic resonance imaging (MRI) have been reported after high-altitude climbs [ 5 – 12 ].…”

Section: Introductionmentioning

confidence: 99%

Morphological Brain Changes after Climbing to Extreme Altitudes—A Prospective Cohort Study

et al. 2015

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BackgroundFindings of cerebral cortical atrophy, white matter lesions and microhemorrhages have been reported in high-altitude climbers. The aim of this study was to evaluate structural cerebral changes in a large cohort of climbers after an ascent to extreme altitudes and to correlate these findings with the severity of hypoxia and neurological signs during the climb.MethodsMagnetic resonance imaging (MRI) studies were performed in 38 mountaineers before and after participating in a high altitude (7126m) climbing expedition. The imaging studies were assessed for occurrence of new WM hyperintensities and microhemorrhages. Changes of partial volume estimates of cerebrospinal fluid, grey matter, and white matter were evaluated by voxel-based morphometry. Arterial oxygen saturation and acute mountain sickness scores were recorded daily during the climb.ResultsOn post-expedition imaging no new white matter hyperintensities were observed. Compared to baseline testing, we observed a significant cerebrospinal fluid fraction increase (0.34% [95% CI 0.10–0.58], p = 0.006) and a white matter fraction reduction (-0.18% [95% CI -0.32–-0.04], p = 0.012), whereas the grey matter fraction remained stable (0.16% [95% CI -0.46–0.13], p = 0.278). Post-expedition imaging revealed new microhemorrhages in 3 of 15 climbers reaching an altitude of over 7000m. Affected climbers had significantly lower oxygen saturation values but not higher acute mountain sickness scores than climbers without microhemorrhages.ConclusionsA single sojourn to extreme altitudes is not associated with development of focal white matter hyperintensities and grey matter atrophy but leads to a decrease in brain white matter fraction. Microhemorrhages indicative of substantial blood-brain barrier disruption occur in a significant number of climbers attaining extreme altitudes.

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Section: Introductionmentioning

confidence: 99%

Morphological Brain Changes after Climbing to Extreme Altitudes—A Prospective Cohort Study

et al. 2015

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“…151 Additionally, motivation and training can effectively compensate for the stress imposed by a high-altitude atmosphere, with motivation a more important factor than training in maintaining performance at high altitude. 49 In 1957, Greene 152 described several effects of chronic hypoxia. For example, chronic hypoxia affects people differently.…”

Section: Individual Differencesmentioning

confidence: 99%

Cognitive performance, mood, and neurological status at high terrestrial elevation

Banderet¹,

Shukitt-Hale²

2002

PsycEXTRA Dataset

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. ABSTRACT (Maximum 200 words)Cognitive and psychomotor performance and mood states, including many critical behavioral functions such as sleep, memory, ■ reasoning, and vigilance, are significantly impaired by ascent to HTE higher than 3,000 m. Impairments in behavior caused by HTE can degrade military operations because the judgment and rate and accuracy of performance of military personnel can be affected. Such adverse effects have distinct and measurable time courses; onset of some effects is immediate (cognitive performance), whereas the onset of others is delayed (symptoms of AMS or adverse moods). The behavioral consequences of HTE are primarily dependent on the level of altitude, the duration of exposure the rate of ascent, an individual's state of physiological acclimation or acclimatization, characteristics of the task performed, and characteristics of the individual such as hypoxic sensitivity. Military history documents that the adverse effects induced by HTE need to be considered when military operations at altitude are planned and undertaken. Current research indicates that some performance decrements induced by ascent to extremely high mountains (e.g., Mount Everest, 8,848 m) may persist for a year or longer after return to lower elevations. Psychological, operational, and medical strategies have been employed to minimize these adverse effects. Psychological strategies often involve training and familiarization with the adverse effects that will be experienced at high altitude. Operational strategies include staging at intermediate altitudes, acclimatizing, and using supplemental oxygen from tanks of oxygen generators. Medical strategies often involve the use of medications to improve functioning at altitude and techniques to avoid complications. In most situations, multiple strategies are employed. The strategies now available and new developments to come will ensure that high-altitude military operations in the future will be less affected by adverse changes in cognitive and psychomotor performance and mood.14. SUBJECT TERMS high altitude, hypoxia, cognitive performance, moods, symptoms, time course of altitude effects, behavior NUMBER OF PAGES 3516. PRICE CODE

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“…Visual degradation is generally consistent and starts occurring at around 1500 m (5000 ft). Over the years, the effect of hypoxia on cognitive performance and mental functioning has been investigated extensively (Cudaback 1984;Greene 1957;Petrassi et al 2012). Motor and cognitive performance impairments vary from person to person and depend on the altitude level and rate of ascent.…”

Section: Hypobaric Stress: Hypoxic Hypoxiamentioning

confidence: 99%

Environmental Stress in Military Settings

Sullivan-Kwantes

Cramer

Bouak

et al. 2021

Handbook of Military Sciences

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During military training and operations, exposure to extremes of noise, temperature, humidity, pressure, or acceleration can induce levels of physiological strain that degrade cognitive and physical capabilities, threaten health and safety, and affect behavior and performance. The overarching purpose of this chapter is to discuss the impact of environmental stress on military personnel. Because each of the aforementioned stressors induces disparate effects, each section addresses a unique stressor in terms of (i) the nature of the threat, (ii) physiological and biomedical effects, (iii) the impact on performance, and (iv) management strategies. The evolution of next-generation wearable biosensors, smart performance algorithms, and scientifically based operational training methods including stress inoculation exposure that will contribute to improved training, adaptation, and tolerance to these operational stresses is discussed.

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Mental Performance in Chronic Anoxia

Cited by 14 publications

References 3 publications

Morphological Brain Changes after Climbing to Extreme Altitudes—A Prospective Cohort Study

Morphological Brain Changes after Climbing to Extreme Altitudes—A Prospective Cohort Study

Cognitive performance, mood, and neurological status at high terrestrial elevation

Environmental Stress in Military Settings

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