The Spanish report is not the only one to examine brain damage in otherwise healthy high-altitude climbers.
By comparing scans of nine climbers' brains before and after trips to K2 or Everest, Dr. Margherita Di Paola and her colleagues at the University of Rome found that the climbers lost both gray and white matter. The study also showed greater damage to the brain regions controlling the dominant side of the bodypresumably from the greater oxygen demands in the parts controlling movement.
A 1996 study in the British journal Clinical Science compared brain scans of 21 elite climbers who had climbed above 26,000 feet and a control group of 21 people who had never been to high altitude. Sixty percent of the elite climbers showed signs of mild cortical atrophy or damage in the white matter deep in the brain. Notably, seven elite Sherpas who climbed that high but lived at high altitude were also studied. Only one showed similar effects. The authors recommended slower acclimatization.