A little help from an exoskeleton

The U-M team has no plans to build a commercial version, but their results suggest promising avenues of research in rehabilitation and physical therapy.

"This could benefit stroke patients or patients with spinal-cord injuries," says Daniel Ferris, associate professor in movement science at U-M. "For patients that can walk slowly, a brace like this may help them walk with less effort."

Ferris and his team found that ankle-exoskeleton users learned to walk in about 30 min. And the wearer's nervous system could control the exoskeleton three days later.

Typically, patients wear robotic rehab devices with a brace that receives instructions from a computer. Such devices use repetition to help force a movement pattern. In the U-M device, however, electrodes on the wearer's leg receive signals from the brain, which are translated into exoskeleton movements.

"The artificial muscles are pneumatic. When the computer gets a signal from the wearer's muscle, it increases air pressure into the artificial muscle on the brace," Ferris says. "Essentially, the artificial muscle contracts with the person's muscle."

The work was supported by a grant from the National Institute of Neurological Disorders and Stroke.