Please use this identifier to cite or link to this item: https://doi.org/10.1371/journal.pone.0174277
Title: Caudwell xtreme everest: A prospective study of the effects of environmental hypoxia on cognitive functioning
Authors: Griva K. 
Stygall J.
Wilson M.H.
Martin D.
Levett D.
Mitchell K.
Mythen M.
Montgomery H.E.
Grocott M.P.
Aref-Adib G.
Edsell M.
Plant T.
Imray C.
Cooke D.
Harrington J.
Khosravi M.
Newman S.P.
Ahuja V.
Burnham R.
Chisholm A.
Clarke K.
Coates D.
Coates M.
Cook D.
Cox M.
Dhillon S.
Dougall C.
Doyle P.
Duncan P.
Edwards L.
Evans L.
Gardiner P.
Gunning P.
Hart N.
Harvey J.
Holloway C.
Howard D.
Hurlbut D.
Ince C.
Jonas M.
Van Der Kaaij J.
Kolfschoten N.
Luery H.
Luks A.
McMorrow R.
Meale P.
Morgan G.
Morgan J.
Murray A.
O'Dwyer M.
Pate J.
Pun M.
Richards P.
Richardson A.
Rodway G.
Simpson J.
Stroud C.
Stroud M.
Symons B.
Szawarski P.
Van Tulleken A.
Van Tulleken C.
Vercueil A.
Wandrag L.
Windsor J.
Basnyat B.
Clarke C.
Hornbein T.
Milledge J.
West J.
Keywords: adult
age
altitude disease
Article
attention
cognitive defect
controlled study
executive function
female
human
incidence
language ability
major clinical study
male
memory
mood
neuropsychological test
prospective study
psychomotor activity
sea level
verbal behavior
altitude
cognition
Cognitive Dysfunction
complication
hypoxia
language
middle aged
pathophysiology
risk factor
Adult
Age Factors
Altitude
Attention
Cognition
Cognitive Dysfunction
Executive Function
Female
Humans
Hypoxia
Incidence
Language
Male
Middle Aged
Neuropsychological Tests
Prospective Studies
Risk Factors
Issue Date: 2017
Citation: Griva K., Stygall J., Wilson M.H., Martin D., Levett D., Mitchell K., Mythen M., Montgomery H.E., Grocott M.P., Aref-Adib G., Edsell M., Plant T., Imray C., Cooke D., Harrington J., Khosravi M., Newman S.P., Ahuja V., Burnham R., Chisholm A., Clarke K., Coates D., Coates M., Cook D., Cox M., Dhillon S., Dougall C., Doyle P., Duncan P., Edwards L., Evans L., Gardiner P., Gunning P., Hart N., Harvey J., Holloway C., Howard D., Hurlbut D., Ince C., Jonas M., Van Der Kaaij J., Kolfschoten N., Luery H., Luks A., McMorrow R., Meale P., Morgan G., Morgan J., Murray A., O'Dwyer M., Pate J., Pun M., Richards P., Richardson A., Rodway G., Simpson J., Stroud C., Stroud M., Symons B., Szawarski P., Van Tulleken A., Van Tulleken C., Vercueil A., Wandrag L., Windsor J., Basnyat B., Clarke C., Hornbein T., Milledge J., West J. (2017). Caudwell xtreme everest: A prospective study of the effects of environmental hypoxia on cognitive functioning. PLoS ONE 12 (3) : e0174277. ScholarBank@NUS Repository. https://doi.org/10.1371/journal.pone.0174277
Rights: Attribution 4.0 International
Abstract: Background: The neuropsychological consequences of exposure to environmental hypobaric hypoxia (EHH) remain unclear. We thus investigated them in a large group of healthy volunteers who trekked to Mount Everest base camp (5,300 m). Methods: A neuropsychological (NP) test battery assessing memory, language, attention, and executive function was administered to 198 participants (age 44.5±13.7 years; 60% male). These were studied at baseline (sea level), 3,500 m (Namche Bazaar), 5,300 m (Everest Base Camp) and on return to 1,300 m (Kathmandu) (attrition rate 23.7%). A comparable control group (n = 25; age 44.5±14.1 years; 60% male) for comparison with trekkers was tested at/or near sea level over an equivalent timeframe so as to account for learning effects associated with repeat testing. The Reliable Change Index (RCI) was used to calculate changes in cognition and neuropsychological function during and after exposure to EHH relative to controls. Results: Overall, attention, verbal ability and executive function declined in those exposed to EHH when the performance of the control group was taken into account (RCI .05 to -.95) with decline persisting at descent. Memory and psychomotor function showed decline at highest ascent only (RCI -.08 to -.56). However, there was inter-individual variability in response: whilst NP performance declined in most, this improved in some trekkers. Cognitive decline was greater amongst older people (r = .42; p < .0001), but was otherwise not consistently associated with socio-demographic, mood, or physiological variables. Conclusions: After correcting for learning effects, attention, verbal abilities and executive functioning declined with exposure to EHH. There was considerable individual variability in the response of brain function to sustained hypoxia with some participants not showing any effects of hypoxia. This might have implications for those facing sustained hypoxia as a result of any disease. © 2017 Griva et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Source Title: PLoS ONE
URI: https://scholarbank.nus.edu.sg/handle/10635/161201
ISSN: 19326203
DOI: 10.1371/journal.pone.0174277
Rights: Attribution 4.0 International
Appears in Collections:Elements
Staff Publications

Show full item record
Files in This Item:
File Description SizeFormatAccess SettingsVersion 
10_1371_journal_pone_0174277.pdf902.75 kBAdobe PDF

OPEN

NoneView/Download

Google ScholarTM

Check

Altmetric


This item is licensed under a Creative Commons License Creative Commons