Do long trips to outer space cause brain damage?

New research has linked spending a long time in outer space with possible brain damage.

This is an Inside Science story.

Over the past several years, scientists have published research suggesting that people's brains change after spending longer than a few months in space. These studies started because astronauts experienced issues like vision problems and swollen optic nerves upon returning to Earth after long missions.

Researchers are now wondering whether these extended trips to space damage the brain. In a new study of five male cosmonauts (Russian astronauts), researchers looked at levels of different proteins in the blood that are often also seen in people with some sort of head trauma or brain disease. They found that on average, the cosmonauts had higher levels of some of the proteins in the three weeks following the mission than before.

Dr. Donna Roberts, a neuroradiologist at the Medical University of South Carolina in Charleston who did not contribute to the new paper, said that more studies need to be done to determine if these changes are clinically significant, but that the new paper is "an example of the type of tests we need to start doing more of" to better understand the effects of the brain's changes during long-duration spaceflight.