Wed, Mar 14, 2012 - Page 7 News List

Brain scans reveal time in space might cause abnormalities

The Guardian, LONDON

Brain scans of NASA astronauts who have returned to Earth after more than a month in space have revealed potentially serious abnormalities that could jeopardize long-term space missions.

Doctors examined 27 astronauts who had flown long-duration missions with the US space agency and found a pattern of deformities in their eyeballs, optic nerves and pituitary glands that remain unexplained.

The problems are similar to those caused by intracranial hypertension, a rare medical condition that occurs when pressure inside the skull rises and presses on the brain and the backs of the eyes.

Medical crews at NASA and space agencies in Europe, Russia, Japan and Canada are now screening astronauts before, during and after space missions.

Astronauts who had flown on the space shuttle and International Space Station reported changes to eyesight, with some seeing worse and others better.

Brain scans revealed that seven of the 27 astronauts had a flattening of the back of one or both eyes. By making the eyeball shorter, this made the astronauts more long-sighted, which in some cases reduced or corrected their short-sightedness.

Larry Kramer, who led the study at the University of Texas Health Science Center in Houston, said the impact on astronauts’ eyesight might become “a new limiting factor” to long excursions into space.

His results, published in the journal Radiology, suggested the abnormalities were worse and more frequent in astronauts who spent longer in weightless, or microgravity, conditions.

“Consider the possible impact on proposed manned missions to Mars or even the concept of space tourism. Can risks be eventually mitigated? Can abnormalities detected be completely reversed? The next step is confirming the findings, defining causation and working towards a solution based on solid evidence,” Kramer said.

Four of the astronauts had swelling around the optic nerve, which could affect the transmission of signals from the eye to the brain and, in the longer term, cause nerve fibers to die off.

The worrying changes add to the effects of bone loss and muscle wastage that astronauts and their medical crews have known about for decades.

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