With jam-packed schedules and a video feed to Earth, astronauts enjoy precious little privacy as it is. Soon, doctors might peek into an astronaut's last bastion of solitude, thanks to a portable brain scanner that could one day go into orbit.

Mission control could use the device to remotely monitor astronauts for signs of brain injury, depression and even mental fatigue that could compromise their ability to make a critical repair of equipment.

"If you had a magic cap to say, 'Are you good to go?' that might be valuable," says Jonathan Clark of the National Space Biomedical Research Institute (NSBRI) in Houston, Texas, US, which funds the work. "Think of it like a breathalyser for the brain."

But the scanner, currently under development at Massachusetts General Hospital in Boston, US, must prove its worth and safety before NASA even considers sending a brain scanner into orbit, Clark tells New Scientist.

Unlike the hulking, tunnel-like MRI machines that peer into the brain with super-strong magnets, the space brain scanner resembles a large remote control tethered to a Velcro headband by long, thin wires.

Yet the technology – called near-infrared optical spectroscopy – works something like functional MRI, which equates changes in blood flow to brain activity.

Mild depressionIn lieu of a magnet, the optical scanner sends weak pulses of near-infrared light into the brain, then reads back the reflected wavelengths. That reveals how much oxygen is in the blood, a gauge of brain activity, says Gary Strangman, a psychiatrist leading development of the scanner, which he and others are already using on Earth-bound patients.

Currently, Strangman's focus is on diagnosing and understanding depression in orbit. Astronauts frequently report feeling despondent, and a recent four-year study of the crew aboard the International Space Station found signs of mild depression and mental fatigue.

After 211 days in space aboard the former Mir space station, cosmonaut Valentin Lebedev noted, according to the NSBRI: "My disposition changed; sunny disposition turned sour."

"People do change in space," says Nick Kanas, a psychiatrist at the University of California in San Francisco, US, who conducted the study of space station crew members. "If you can demonstrate their cognition changes, as well as gets slowed down in some way, then it would be very useful to have a tool to assess this."

In orbit, the scanner might look for changes in brain activity in regions that have been previously linked to depression, Strangman says.

Mental stressIt could also be used to sense brain damage caused by environmental problems – such as low oxygen or carbon monoxide – in the shuttle or space station.

More controversially, it might help avoid close calls – and even catastrophe – by picking up on signs of mental stress before they're apparent to an astronaut or the crew. However, such a sensor may not be popular with astronauts.

"Having a little black box telling them they may not to be able to do what they've been training for may not go over well, as you could imagine," Strangman says.

However, Strangman's space scanner isn't a fait accompli. Although his lab will receive around $400,000 from NASA's biomedical arm to develop the brain scanner, the agency will need proof of its usefulness to green light the device for flight, Clark says.

That could mean measuring other vital signs, such as blood pressure and heart rate. Ideally, NASA would want a Swiss Army knife for the body. But with few competing technologies, Strangman's brain scanner looks promising, Clark says.

"As it stands, it's pretty much the only game in town for trying to monitor brain status," he says.

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RESOURCE/SOURCE: http://space.newscientist.com/article/dn14247-brain-breathalysers-may-scan-astronauts-for-stress.html?feedId=online-news_rss20 on Thursday July 3, 2008.