Peter Rogers, How long-term space missions change the brain, Big Think, May 15, 2022.
According to the 2015 NASA report, astronauts who spent long periods in space described motor-control problems and vision impairment, neither of which are ideal for individuals operating billion-dollar pieces of equipment in outer space.
One particularly common visual impairment, spaceflight-associated neuro-ocular syndrome (SANS), affects up to 70% of NASA astronauts who undergo long-duration missions aboard the International Space Station (ISS). These symptom indicated neurological changes, so it became more common for astronauts to undergo MRIs before and after missions.
These brain scans revealed significant structural changes. The group of international researchers sought to determine whether these changes in the brain are associated with SANS. Donna Roberts, M.D., a neuroradiologist at the Medical University of South Carolina who helped lead the study, explained in a press release:
"By putting all our data together, we have a larger subject number. That's important when you do this type of study. When you're looking for statistical significance, you need to have larger numbers of subjects." [...]
After being in space, all the space travelers exhibited similar brain changes: cerebrospinal fluid buildup and reduced space between the brain and the surrounding membrane at the top of the head. The Americans, however, also had more enlargement in the regions of the brain that serve as a cleaning system during sleep, e.g. the perivascular space (PVS).
