Media Contacts

Vincent Horiuchi

Public relations associate, College of Engineering
Phone: 801-585-7499

Jul 24, 2019 12:00 PM


What seems simple for nearly everyone else can be more of a Herculean task for Walgamott, who lost his left hand and part of his arm in an electrical accident 17 years ago. But he was testing out the prototype of a high-tech prosthetic arm with fingers that not only can move, they can move with his thoughts. And thanks to a biomedical engineering team at the University of Utah in collaboration with a rehabilitation specialist and surgeon at U of U Health, he “felt” the egg well enough so his brain could tell the prosthetic hand not to squeeze too hard.

That’s because the team, led by U biomedical engineering associate professor Gregory Clark, Ph.D., has developed a way for the “LUKE Arm” (so named after the robotic hand that Luke Skywalker got in “The Empire Strikes Back”) to mimic the way a human hand feels objects by sending the appropriate signals to the brain. Their findings were published in a new paper co-authored by U biomedical engineering doctoral student Jacob George, physical medicine and rehabilitation assistant professor Christopher Duncan, M.D., orthopedics professor Douglas Hutchinson, M.D., and other colleagues, in the latest edition of the journal Science Robotics.

“We changed the way we are sending that information to the brain so that it matches the human body. And by matching the human body, we were able to see improved benefits,” says George “We’re making more biologically realistic signals.”

That means an amputee wearing the prosthetic arm can sense the touch of something soft or hard, understand better how to pick it up, and perform delicate tasks that would otherwise be impossible with a standard prosthetic with metal hooks or claws for hands.


After hand surgeon Douglas Hutchinson, M.D., implanted several arrays of electrodes into Walgamott’s nerves and the muscles in his forearm that help control the hand and wrist, he was able to test the LUKE arm. In Clark’s lab, Walgamott plucked grapes without crushing them, picked up an egg without cracking it, and held his wife’s hand with a sensation in the fingers similar to that of an able-bodied person.

“They feel their sense of self is returned,” says Hutchinson referring to study participants like Walgamott. “And that’s a big, wonderful thing.”

Rehabilitation specialist Duncan focused on an early phase of the study in an attempt to answer a fundamental question. “How does a person move through their space if they’re missing their hands?” he asks. “Your thoughts and feelings might be the same but your ability to act on them is substantially limited.”

Duncan began to find out by 3-D printing hands and implanting sensors so volunteers could start to control the prosthetics with their thoughts. These initial steps were a bridge to the LUKE hand.

“We’re learning how important it is to sense an object when you’re picking it up and manipulating it and how much, paradoxically, it makes it more a part of your body to just perceive sensation,” says Duncan. “It’s something that becomes a part of your body.”

The LUKE Arm


Meanwhile, the U team has been developing a system that allows the prosthetic arm to tap into the wearer’s nerves, which are like biological wires that send signals to the arm to move. It does that thanks to an invention by University of Utah biomedical engineering Emeritus Distinguished Professor Richard A. Normann called the Utah Slanted Electrode Array. The Array is a bundle of 100 microelectrodes and wires that are implanted into the amputee’s nerves in the forearm and connected to a computer outside the body. The array interprets the signals from the still-remaining arm nerves, and the computer translates them to digital signals that tell the arm to move.





Future Research




The research involves a number of institutions including the U’s Department of Neurosurgery, Department of Physical Medicine and Rehabilitation and Department of Orthopedics, the University of Chicago’s Department of Organismal Biology and Anatomy, the Cleveland Clinic’s Department of Biomedical Engineering, and Utah neurotechnology companies Ripple Neuro LLC and Blackrock Microsystems. The project is funded by the Defense Advanced Research Projects Agency and the National Science Foundation.


Research News