After the bionic limbs controlled by the nerves of the amputee, now researchers have designed a robotic exoskeleton commanded by the body's nerves. "A robotic exoskeleton controlled by the wearer's own nervous system could help users regain limb function, which is encouraging news for people with partial nervous system impairment," says University of Michigan team.

Initially, the ankle exoskeleton was probed by healthy volunteers to assess how it affected ankle function.

The researchers did not start their investigation for commercial purposes, but the technology seems promising for rehabilitation and physical therapy. "This could benefit stroke patients or patients with incomplete injuries of the spinal cord," said Daniel Ferris, associate professor in movement science at U-M. "For patients that can walk slowly, a brace like this may help them walk faster and more effectively."

Those wearing the exoskeleton learned how to walk with it in about 30 minutes. Moreover, the subject's nervous system maintained the ability to control the exoskeleton for three days. Electrical signals sent by the brain to our muscles tell them how to move.

People that suffered spinal injuries or neurological impairments received weak or uncoordinated brain electric commands. These patients lose capacity to keep track of exactly where and how their muscles act, which makes re-learning movement even more difficult.

Most robotic rehabilitative devices move the limb receiving commands from a computer and employ repetition to enforce a movement pattern, but the robotic exoskeleton works differently. Electrodes were attached to the wearer's leg, picking up electrical signals sent by the brain and translating them into movement commands for the exoskeleton. "The (artificial) muscles are pneumatic. When the computer gets the electrical signal from the (wearer's) muscle, it increases the air pressure into the artificial muscle on the brace," Ferris said. "Essentially the artificial muscle contracts with the person's muscle."

As the exoskeleton makes the muscle stronger, the initial gait is disrupted, but in 30 minutes, the wearers adapted to the skeleton and used their muscles less. "The next step is to test the device on patients with impaired muscle function," Ferris said.

Image credit: University of Michigan