Jet Pilots High Altitude Brain Lesions
August 20, 2013

Jet Pilots More Likely To Develop Dangerous Brain Lesions

Lee Rannals for - Your Universe Online

A study published in the journal Neurology found that high altitudes may increase the risk of brain lesions. Researchers reported that pilots who fly at high altitudes for extended periods of time are more likely to have brain lesions than non-pilots.

The team performed MRI brain scans on 102 U-2 United States Air Force pilots and 91 non-pilots between the ages of 26 and 50. During the scans, the scientists measured the amount of white matter hyperintensities, or tiny brain lesions associated with memory decline in other neurological disorders.

"Pilots who fly at altitudes above 18,000 feet are at risk for decompression sickness, a condition where gas or atmospheric pressure reaches lower levels than those within body tissues and forms bubbles," said study author Stephen McGuire, MD, with the University of Texas in San Antonio, the US Air Force School of Aerospace Medicine and a Fellow of the American Academy of Neurology.

McGuire said the risk for this sickness among Air Force pilots has tripled since 2006, potentially due to more frequent flights and longer periods of exposure to the higher altitudes. He added that so far they have not been able to demonstrate any permanent clinical neurocognitive or memory decline in the pilots. Symptoms that can accompany decompression sickness include slowed thought processes, confusion, unresponsiveness and permanent memory loss.

The researchers discovered that pilots had nearly four times the volume and three times the number of brain lesions as non-pilots in the study. They said the results were the same whether or not the pilots had a history of symptoms of decompression sickness. Lesions in non-pilots were mainly found in the frontal white matter, while lesions in the pilots were evenly distributed throughout the brain.

"These results may be valuable in assessing risk for occupations that include high-altitude mountain climbing, deep sea diving and high-altitude flying," McGuire said.

In 2010, scientists discovered a genetic feature that has evolved in Tibetans to help them live more comfortably in higher elevations. People who live in Tibet thrive in an environment with an average elevation of 16,000 feet. Scientists found that Tibetans have developed a special genetic adaptation that allows them to breath easier in the higher altitude, as well as keep clear from altitude sickness.

Scientists from the pilot study could continue their research by comparing the pilot MRI scans with people in Tibet to see if their genetic development has also helped keep them from developing brain lesions.