Astronaut balancing act: Training to help explorers adapt to a return to gravity

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Astronaut balancing act: Training to help explorers adapt to a return to gravity

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National Space Biomedical Research Institute (NSBRI) and NASA researchers are

developing techniques to help astronauts adapt quickly to a new gravity

environment and to overcome balance disturbances. They are using an Adaptability

Training System that induces balance disturbances through support surface

movement and changes in visual information. The system consists of a treadmill

mounted on a base that can be actively moved in different directions paired with

a virtual scene projected in front of the subject providing a variety of balance

challenges as the user walks. (Photo by NASA.) Click the image to see a larger

version.

Astronauts returning from challenging long-duration missions face one more

challenge when they get back to Earth – standing up and walking.

Upon returning to normal gravity, astronauts often suffer from balance problems

that lead to dizziness and difficulty standing, walking and turning corners. Dr.

Bloomberg is leading a group of National Space Biomedical Research

Institute (NSBRI) scientists in a project to develop techniques to help

astronauts adapt quickly to a new gravity environment and to overcome balance

disturbances. This concept will also have benefits for non-astronaut populations

such as the elderly or people with balance disorders.

Bloomberg of NASA Space Center Neurosciences Laboratory and his

colleagues use a system that consists of a treadmill mounted on a base that can

be actively moved in different directions to simulate balance disturbances.

Called an Adaptability Training System, the treadmill has a projection screen in

front of it that shows an image of a room or hallway that moves as the user

walks. Disturbances are simulated by tilting the treadmill in one direction as

the image is tilted in another.

" At first, people find it difficult to walk on the treadmill since its movement

and images are out of sync. But over time, they learn to walk on it efficiently.

We call this concept `learning to learn,' " said Bloomberg, who is the associate

team leader of NSBRI's Sensorimotor Adaptation Team and a senior research

scientist at NASA.

In order to perform everyday activities, the brain interprets information

provided by the body's sensory systems: the eyes, the inner ear balance organs,

the skin and muscle movement receptors. Bloomberg said the problems for

astronauts occur during the transition period in which the brain is trying to

adapt to a new gravity environment – either returning to Earth or in the future

adjusting to lunar or martian gravity.

" In space, information from the sensory systems is different, particularly when

you take away gravity. The brain reinterprets that information, makes

adjustments and allows you to do the activities you need to do in space, "

Bloomberg said. " The down side to that is when you return to Earth, the sensory

systems are not used to a normal gravity environment. "

Former NASA astronaut Dr. Leroy Chiao experienced balance disturbances following

his four spaceflights, one of which was a six-month stay on the International

Space Station (ISS). He compared the effects to those experienced after stepping

off a fast-spinning playground merry-go-round. " After a merry-go-round ride, the

effects go away pretty quickly, " Chiao said. " But after a spaceflight, they

linger. "

Post-flight data collected indicates a correlation between the length of the

mission and how long effects linger. Bloomberg said if an astronaut has been in

space on a typical two-week shuttle mission, it may take several days to

recover. For six-month stays aboard the ISS, it could take at least several

weeks to return to normal.

In addition to maximizing training efficiency, Bloomberg is looking at how long

the benefit of the adaptability training lasts. Once subjects master the

treadmill, they come back periodically for testing to see how well they perform.

He is investigating if subjects can retain the training for up to six months,

which would allow the training to take place before a long space mission.

Another goal of the researchers is to integrate a version of the system into the

treadmill on a spacecraft, allowing astronauts to perform adaptability training

on long missions. Integration would save space and power, both precious

commodities on a spacecraft.

Chiao, who is the chairman of NSBRI's User Panel, said the research could

provide insight about much longer missions. " On a flight to Mars, astronauts

will be in zero-gravity for six months or more. When they get to Mars, they will

experience one-third gravity, " Chiao said. " Will systems like this allow them to

go to work right away? Or will there need to be a recovery period or procedures

before exploration can begin? These are important questions that this research

is addressing. "

Project co-investigator Dr. Helen Cohen, professor of otolaryngology at Baylor

College of Medicine, said, " It will not be a good situation if an astronaut

lands on a new planet and has problems maintaining balance. The training could

help maintain astronaut safety and help them accomplish mission objectives. "

Sensorimotor disturbances are not limited to standing up and walking. " Some

people with inner ear trouble don't steer a vehicle well, " said Cohen, associate

director of the Center for Balance Disorders at BCM. " Adaptability training

could also help people to perform these types of tasks better. "

Even though the cause of the sensorimotor problems is different, Bloomberg said

the adaptability training concept could help prevent falls in the elderly.

" For astronauts, the sensory systems are working just fine but the information

is being interpreted differently. For the elderly, it could be a combination of

issues: the sensory systems may be deteriorated or the information may not be

integrated by the brain as well as before, " he said. " We might use this training

to improve some of the deficits that the elderly might experience. There are

definitely applications in the clinical world in terms of fall prevention with

the elderly population. "