A Colorado man has become the first bilateral shoulder-level amputee to wear and simultaneously control two modular prosthetic limbs with his mind at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.
Les Baugh, who lost both arms 40 years ago in an electrical accident, was able to operate the system by simply thinking about moving his limbs, performing a variety of tasks during a short training period, according to a press release.
Before operating the system, Baugh underwent a targeted muscle reinnervation surgery.
“It’s a relatively new surgical procedure that reassigns nerves that once controlled the arm and the hand,” Albert Chi, MD, a Johns Hopkins trauma surgeon, said in the press 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.”
After recovery, Baugh visited the laboratory for training on the use of the modular prosthetic limbs (MPLs). First, he worked with researchers on the pattern recognition system. Then Baugh was fitted for a custom socket for his torso and shoulders that supports the prosthetic limbs and also makes the neurological connections with the reinnervated nerves. While the socket got its finishing touches, the team had Baugh work with the limb system through a virtual integration environment, a virtual-reality version of the MPL.
When Baugh was fitted with the socket, and the prosthetic limbs were attached, he 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 task simulated activities that may commonly be faced in a day-to-day environment at home,” Courtney Moran, CP, MS, who worked with Baugh on his recovery, said in the release. “This was significant because this is not possible with currently available prostheses. He was able to do this with only 10 days of training, which demonstrates the intuitive nature of the control.”
Moran said the research team was floored by what Baugh was able to accomplish.
“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,” she said in the release. “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.”