Background: Every year million people visit high altitude areas. Studies indicate that at 3000 – 4000 meters above sea level, 25% of subjects suffer from acute mountain sickness. It is claimed that brain function might be depressed, but is this something that can be measured? Tales of strange behaviour and dangerous situations during climbs are numerous. Could it be that altered brain performance is the reason for this?
Objectives: Our goal was to investigate whether the current literature supports the hypothesis that cognitive function is reduced at high altitudes.
Material and methods: By performing a limited search in PubMed 11 publications were identified and here presented as a review. Search terms used were: altitude or mountain combined with cognitive or brain performance.
Results: Six publications found a reduction in cognitive function, three were inconclusive due to limited numbers of subjects while one author reported an increase in cognitive function. It was not possible to compare these publications directly, mainly because the term “cognitive function” was not specifically defined. We found a cut of point at 5 000 meters above sea level where all articles showed a reduction in cognitive function regardless of quality tested.
Conclusion: Research performed during climbs often suffers under the participants’ determination to reach the top, and the studies are of a rather poor quality. Nevertheless, they do indicate that cognitive function is altered during high climbs independent of acclimatisation and that cognitive function probably can be measured if better methods are developed.
Supervisor: Anton HaugeInstitute of Basic Medical Sciences. Faculty of Medicine, University of Oslo.