Tiny robots to help amputees control prosthetics
Researchers in Canada and the U.S. have developed technology that is giving the sensation of feeling back to amputees and helping those missing limbs feel connected to their motorized prosthetics.
Using miniature custom-made robots to stimulate nerve endings at the base of the amputation, the team focused its attention on engineering a real-world application of the movement illusion concept.
Study co-author and rehabilitation physician at Edmonton’s Glenrose Rehab Hospital, Dr. Jacqueline Hebert, said current technology uses muscle signals to open and close a motorized prosthetic. But it’s an imperfect science.
Without the sensation of feeling, the bionic arm operates at maximum effort, meaning that if the amputee is not watching their hand, there is a tendency to crush an object or drop it.
However, by coupling the vibration robots with targeted nerve innervation — in which surgeons go in and rewire the nerves that are left in the person’s residual limb — researchers have been able to provide amputees with the sensation of the missing hand.
The tiny robots stimulating the nerves have a soft head that pushes into the muscle on the skin inside the socket with a certain force and that vibrates at a really fast frequency.
That is then synchronized with the movement of the hand so when amputees are activating the prosthetic hand, the vibration creates the appropriate feeling.
“We are harnessing that illusion to provide that person’s brain with the feeling that the limb is moving in a way that it feels like their own hand is moving and we match that with the prosthetic movement,” she said.
“We are just giving the brain information it desperately wants. It just wants to know how things are moving.
“We are essentially closing the loop.”
Next up, Hebert said they plan to test the technology on all levels of amputation, including those who have not had the innervation surgery.
There are also plans to continue to shrink the tiny robots even further.
The researchers’ findings from their four-year study are published in the journal Science Translational Medicine.