Project Receives Funding From UCNI Schofield is part of a team of engineers, scientists and surgeons at UC Davis working to make life easier for amputees through a combination of surgery, advanced machine learning and smart prosthetics. It is work that recently received funding from UCNI. Their goal is “prosthesis embodiment,” to get these devices to mimic a biological limb so amputees gain better muscle control and sensory feedback without increased complexity. “We’re trying to fill that gap,” Schofield said. “We’re asking how can we allow someone to think about making a pinching motion or think about making a fist with their missing hand and just let the prosthetic limb do that for them.” Brockman is taking part in an experiment to help the UC Davis group and other researchers advance prosthetics. He now has a new myoelectric prosthetic hand, one much closer to the real thing. It looks like a glove and its fingers can move independently. Brockman said the new prosthetic hand will make a huge difference in his life. “For me, I love the outdoors. This is a dream come true because I’ll be able to grab my fishing pole and reel and grab things again instead of trying to hook it and it keeps slipping off,” he said.
Advanced Prosthetics Difficult to Operate Myoelectric devices, which use muscle activity from the remaining limb to operate, still require a lot of effort to get them to work, said Laduan Smedley, a certified prosthetist orthotist at UC Davis Health. “I describe it somewhat like Morse code,” Smedley said. “Amputees have to memorize these kinds of patterns of flexion and extension or co-contraction to operate the hand.” Some of the more advanced myoelectric hands are more intuitive but require a smartphone app to select the desired type of grasp, such as pinching or gripping. The UC Davis research group wants to incorporate what scientists know about how humans learn and control movement, said Wilsaan Joiner, a UCNI scholar, neuroscientist and professor in the Department of Neurobiology, Physiology and Behavior in the College of Biological Sciences. “If you’re not utilizing what is a natural ability or natural infrastructure of our motor system to control an external device, it’s probably going to be incredibly difficult and nonintuitive to learn how to do,” Joiner said.
Peyton Young, a UC Davis Ph.D. candidate in the lab of UC Noyce Initiative researcher Jonathon Schofield, demonstrates how electromyography works using a robotic arm. The robotic arm recognizes the electrical signals from his forearm muscles and it moves accordingly. (Gregory Urquiaga/UC Davis)
UC Davis Health certified prosthetist orthotist Laduan Smedley is making sure the sleeve of David Brockman’s prosthetic hand fits correctly. (Gregory Urquiaga/UC Davis)
Amputations Improved by Targeted Muscle Reinnervation Surgeons have led the way to make myoelectric devices easier to use. Not long ago, the standard amputation could still leave patients in a lot of pain. Surgeons cut bone, muscle and nerves to remove a limb. They buried those nerves under muscle or in bone to prevent their endings from growing toward the surface of the skin. “The idea was that if you bury it far away from the skin then patients don’t get pain,” said Clifford Pereira, an associate professor in the Department of Surgery at UC Davis Health and UCNI scholar. “We found that despite doing that, people still get chronic pain and phantom pain.”
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