Amputee able to control prosthetic limbs through thought

By simply thinking about moving his prosthetic limbs, a Colorado man is regaining control he’s missed since he lost his arms in an electrical accident 40 years ago.

Les Baugh became the first bilateral shoulder-level amputee to wear and simultaneously control two Modular Prosthetic Limbs (MPL), which was developed by the Johns Hopkins University Applied Physics Laboratory (APL) as part of the Revolutionizing Prosthetics Program (RP).

In June, Baugh underwent a surgery at John Hopkins Hospital known as targeted muscle reinnervation.

“It’s a relatively new surgical procedure that reassigns nerves that once controlled the arm and the hand,” Johns Hopkins trauma surgeon Dr. Albert Chi explained in a news release. “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.”

“I went into the surgery knowing that he was going to move nerves in my chest. I remember when I first [came] out from under it, the pain, I’d never had, I don’t even remember the original being that much excruciating pain but I imagine probably that my mind blocked that anyway,” Baugh said in a video released by researchers.

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After recovery, Baugh received MPL training at the laboratory. Researchers worked with him on the pattern recognition system that identified individual muscle contractions and how the muscles communicate with one another. That information is then translated into actual movements with the prosthetic.

Baugh was fitted with a custom socket, a type of body brace that makes neural connections with re-innervated nerves and supports the prosthetic limbs. The team then had Baugh work with the limb system through a virtual-reality  version of the MPL.

“Once the training sessions were complete and they released me and let me be the computer, basically, to control that arm, I just went into a whole different world,” Baugh said.

Baugh was able to move several objects, including an empty cup from a counter-shelf height to a higher shelf— a task that required him to coordinate the control of eight separate motions to complete.

This movement is not possible with currently available prostheses, researchers noted.

“He was able to do this with only 10 days of training, which demonstrates the intuitive nature of the control,” said APL’s Courtney Moran, clinical lead for amputee research, adding that the team was floored by what Baugh was able to accomplish.

“I think we’re just getting started at this point. It’s like the early days of the Internet, there’s just a tremendous amount of potential ahead of us and we just started down this road and I think the next five, 10 years is going to bring some really phenomenal advancements,” Mike McLoughlin, RP principal investigator, said in the news release.

The next step is to send Baugh home with a pair of limb systems so he can work on integrating them with his everyday life.

Baugh is looking forward to that day.

“Maybe I’ll be able to for once put change in a pop machine, get the pop out— simple things like that that most people never think of,” he said. “And it’s re-available to me.”