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Physiol Behav. 2015 Apr 1;142:104-10. doi: 10.1016/j.physbeh.2015.02.006. Epub 2015 Feb 4.

Acute hypoxic gas breathing severely impairs cognition and task learning in humans.

Author information

1
Exercise Neurometabolism Laboratory, Centre for Brain Research, The University of Auckland, New Zealand.
2
School of Psychology, Centre for Brain Research, The University of Auckland, New Zealand.
3
Exercise Neurometabolism Laboratory, Centre for Brain Research, The University of Auckland, New Zealand. Electronic address: n.gant@auckland.ac.nz.

Abstract

Impairments in neural function are common when oxygen supply to the brain is reduced. This study examined neurocognitive processes that are vulnerable to oxygen deprivation. We induced moderate-to-severe hypoxia in healthy adults, thereby inducing impairments caused by low brain oxygen availability. 22 healthy adults participated in this matched-pairs study with a single-blind, randomised design. Baseline neurocognitive function was examined during a familiarisation trial and participants were assigned to hypoxia (10% O2) or sham (21% O2) groups. Neurocognitive performance was assessed via computerised test battery after 50 min of breathing a gas mixture that reduced arterial oxygen saturation by 20% (p<0.01). Hypoxia severely reduced performance across all neurocognitive domain scores; with significant drops in neurocognitive index (-20%), composite memory (-30%), verbal memory (-34%), visual memory (-23%), processing speed (-36%), executive function (-20%), psychomotor speed (-24%), reaction time (-10%), complex attention (-19%) and cognitive flexibility (-18%; all p<0.05). Practice effects were blocked by hypoxia but occurred in sham for information processing speed (+30%), executive function (+14%), psychomotor speed (+18%), reaction time (+5%), cognitive flexibility (+14%), and overall cognitive functioning (+9%; all p<0.05). Neuropsychological performance decrements caused by acute experimental hypoxia are comparable to cognitive domains impaired with high altitude exposure and mild traumatic brain injury.

KEYWORDS:

High-altitude; Hypoxic emergencies; Learning effects; Mild traumatic brain injury; Neurocognition; Oxygen deprivation

PMID:
25660759
DOI:
10.1016/j.physbeh.2015.02.006
[Indexed for MEDLINE]

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