THURSDAY, Nov. 21, 2024 (HealthDay News) -- For astronauts who spend months at a time working on the International Space Station (ISS), there's good news.

While their bodies and brains are affected by radiation, altered gravity, challenging working situations and sleep loss on these missions, a study of 25 astronauts found no evidence that those conditions damage their thinking skills over the long haul.

"Living and working in space was not associated with widespread cognitive impairment that would be suggestive of significant brain damage," said first author Sheena Dev, of NASA's Behavioral Health and Performance Laboratory.

During space deployments, astronauts must perform complex tasks and even small mistakes can have serious consequences. 

On average, those participating in this study worked six months on the ISS. 

Tests of mental skills administered before, during and after their missions did show some changes, but nothing permanent or suggestive of damage to the central nervous system, researchers said.

For the study, astronauts took a series of tests to measure speed and accuracy on various mental tasks. They were tested before their mission, during early and late flight, and again at 10 and 30 days after returning to Earth.

In space, they took longer to complete tests of mental processing speed, working memory and attention, the study found. But their results were no less accurate than on Earth. Changes lasted for different periods.

"Slowed performance on attention, for example, was only observed early during the mission while slowed performance on processing speed did not return to baseline levels until after the mission ended and crew were back on Earth," Dev said.

The tests did show that some cognitive domains were more likely to be affected than others.

"Even on Earth, processing speed, working memory and attention are cognitive domains that can show temporary changes when an individual is under stress," Dev said. "Other domains, such as memory, are less vulnerable."

By way of explanation, she noted that a wakeful night usually makes it harder to pay attention at work the next day or more time-consuming to complete tasks.

Astronauts face these same stressors, but others that are unique to space also take a toll, the study showed.

"We found that the most vulnerable domains while astronauts are aboard the ISS are the same as those that are more susceptible to stressors on Earth," they said.

Researchers said the study, published Nov. 19 in the journal Frontiers in Physiology, sheds light on which changes in mental functioning might be expected when humans go to extreme environments. 

It didn't show why changes happened, however. Nor did it set out to evaluate whether astronauts' operational performance suffered.

"It could be that even in areas with observed declines, astronauts were still able to compensate and effectively complete their tasks," Dev said in a journal news release.

Researchers expect this data from the low Earth orbit to be valuable once astronauts head to the moon, Mars or even deeper into space. The data provide a comparison that can help detect cognitive changes brought about by increased radiation exposure and extended communication delays more quickly, researchers said.

More information

There's more about how space travel affects the human body at the Baylor Center for Space Medicine.

SOURCE: Frontiers, news release, Nov. 20, 2024