Italian researchers took MRI scans of nine world-class mountain climbers, who had been climbing for at least 10 years, before and after expeditions to Mount Everest (8,848 metres) and K2 (8,611 metres) without an oxygen supply. They compared their MRI brain scans with 19 age and sex matched healthy control subjects.
Both the climbers and controls were carefully checked to exclude the presence of any major systemic, psychiatric or neurological illnesses. None of the control group subjects had any history of high-altitude exposure over 3,000 metres.
The results demonstrated that the climbers showed a reduction in both the density and volume of white matter in the left pyramidal tract, near the primary and supplementary motor cortex, when their baseline measurements were compared with the control group.
And when the researchers compared the before and after scans for the climbers, they also found a reduction in the density and volume of grey matter in the left angular gyrus.
“The aim of our study was to measure the quantitative loss of white and grey matter, using voxel-based morphometry, which takes spatial, unbiased MRI measurements independent of the operator” explains lead author Dr Margherita Di Paola from the Neuroimaging Laboratory at the IRCCS Fondazione Santa Lucia in Rome.
“The scans were then assessed by two experienced observers who were unaware of whether the scans belonged to the climbers or control group.”
All the climbers who took part in the study - carried out in collaboration with the National Research Council, Institute of Biomedical Technologies, Milan, and the Ev-K2-CNR Committee – were male.
They ranged from 31 to 52 years, with an average age of just under 38, and were used to climbing to altitudes of at least 4,000 metres several times a year.
The researchers took the first scans eight weeks before the expedition began and the second set eight weeks after they returned.
One climber reached the top of Everest and K2 and two reached the top of one mountain. The remainder reached altitudes of over 7,500 metres and spent at least 15 days over altitudes of 6,500 metres.
A number of neuropsychological tests were also carried out to assess the climber’s cognitive abilities, such as memory and motor functions.
“Despite the loss of grey and white matter, the climbers in our study did not suffer any significant neuropsychological changes after the expedition” says Dr Di Paola.
“Some of the subjects did show abnormal scores on the neuropsychological tests, but in these cases there was no significant difference between the baseline and follow up results. This suggests that there were no significant changes as a result of a single expedition.
“As they had been carefully checked for any pathological conditions that could cause these abnormal scores, we conclude that these test results are most likely to be due to progressive, subtle, brain insults caused by repeated high-altitude exposure.”
Overall, the researchers found that the cognitive abilities that were most likely to be affected were the climbers’ executive function and memory. Indeed, six of the nine climbers had lower than average scores on the Digit Symbol test, which measures executive functions such as the ability to anticipate outcomes and adapt to changing situations.
Four scored lower than average on the Block Design test, which measures visuo-motor functions, and three out of nine scored lower than average on the Prose Memory test (immediate recall) and on the Rey’s Figure test (delayed recall), which measure the verbal and visuo-spatial memory respectively.
“Our results provide evidence that extremely high-altitude climbs with no external oxygen supply may cause subtle changes in brain tissue, even when well acclimatised individuals do not experience any neurological symptoms” concludes Dr Di Paola.
“These changes in white and grey matter appear to be highly specific to regions of the brain involved in motor activity.”
Annette Whibley | alfa
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy