Balancing act

The third system involved with balance, called proprioceptive, consists of sensory information from muscles and joints that indicate their relative locations. (It's how you can touch your nose with your eyes closed.)

Defects in the brain's processing ability or in any of the systems - caused by infection, trauma, or slowed response time - can result in symptoms ranging from vertigo to nausea.

While the Temple lab does mainly basic science that may shape future rehab, some other labs are using virtual reality for rehabilitation. Iraq war veterans with post-traumatic stress disorder, for example, have been desensitized through gradual exposure to virtual war. The University of Southern California is creating virtual environments that require specific motor movements within a game for rehabilitation.

Researchers at the University of Pittsburgh study and treat people with balance-related anxiety disorders in a virtual grocery store - it makes them sweaty and nauseous to move down the aisle in combination with all the head movements required to scan products in a busy environment.

Slaboda spent her first year as a Temple post-doc studying how children and adults stand up. Each subject was seated on a stool surrounded by the artificial scene, which she made to pitch (nose up or down, as in an airplane) or roll (wing up or down).

Under one condition, they were told to stand up as soon as the room began to move. Under another condition, they sat and watched for 10 seconds, and then were told to stand.

With all the data creating stick figures in her computer, Slaboda analyzed how they stood up - calculating the angles of head to trunk, trunk to leg, and plotting graphs of flexion and extension and time between movements.

Bottom line: "If you sit and watch first, you'll stand up slower," she said, because you had more time to become disoriented. She submitted her findings to a journal for publication last week and will soon begin the second half of her study: how stroke patients stand up.

The handful of researchers affiliated with the lab come from a variety of disciplines. Slaboda has a doctorate in biomedical engineering. Keshner has expertise in dance, engineering, special education and movement science, in addition to physical therapy.

Jay Barton, the lab manager, is researching the brain-machine interface for the creation of prosthetic limbs controlled by thought. His training as an electrical engineer took him only so far. The biomechanics of real people offers surprises. Such as:

"How an engineer would design the body is not how the body operates," he said.

Look for links to animation and video of how balance works at:

See VIRTUAL on D2