Les Baugh lost both of his arms at the shoulder level to an electrical accident 40 years ago. It’s a long time to adjust to life without them, to forget them.
But it’s all coming back to him now thanks to new research at Johns Hopkins University Applied Physics Laboratory (APL), where Baugh has shown he can use his mind to control high-tech Modular Prosthetic Limbs (MPLs) and complete everyday tasks.
Baugh underwent a surgery called targeted muscle reinnervation to prepare his body to use the limbs.
“It’s a relatively new surgical procedure that reassigns nerves that once controlled the arm and the hand,” explained John Hopkins Trauma Surgeon Albert Chi, M.D. “By reassigning existing nerves, we can make it possible for people who have had upper-arm amputations to control their prosthetic devices by merely thinking about the action they want to perform.”
The arms are attached to Baugh’s torso and shoulder through a custom socket that also makes a connection to the reinnervated nerves. An algorithm identifies Baugh’s muscle contractions and translates them to movements within the arms.
What this means is that, with practice, Baugh has learned to control the limbs just by thinking about what he wants them to do.
“I just went into a whole different world,” said Baugh, who used the limbs to make complex motions like moving a cup to a higher shelf and other everyday tasks that just aren’t possible with the prostheses currently available to him.
Researchers were surprised at how adept Baugh became with the system in just 10 days.
“We expected him to exceed performance compared to what he might achieve with conventional systems, but the speed with which he learned motions and the number of motions he was able to control in such a short period of time was far beyond expectation,” APL’s Courtney Moran, a prosthetist working with Baugh, said. “What really was amazing, and was another major milestone with MPL control, was his ability to control a combination of motions across both arms at the same time. This was a first for simultaneous bimanual control.”
Soon the researchers hope to send Baugh home with a pair of the arms. He says he looking forward to the new arms because it will allow him to do “simple things that most people don’t think of. And it’s re-available to me.”