In the shadows of his North Salt Lake garage, Matthew Beckstead uses the ends of his arms to cradle the conduit pipe that almost killed him. These aren’t stumps, he says. “A stump is the end of a tree. I call them my arms.” He points with his chin to the grooves in the metal. “Here’s where my ﬁngers melted into the pipe,” he says. Beckstead was just 19 when he lost his arms below the elbow in 1998 while working on a billboard in Ogden. He was holding the conduit pipe he now keeps as a souvenir when an illegal power line sent 27,000 volts through his hands. He fell in ﬂames to the ground, only for the impact to restart his heart.
The double amputee says he had to reteach himself how to put on his socks, bathe, go to the bathroom, and make food, as well as how to ﬁsh, hunt, mow the lawn, and care for his wife and three children. Despite his relentless pursuit of self-sufficiency, the dream of one day getting his hands back, as opposed to using the most up-to-date commercial prosthetics currently languishing in his closet, remained just a dream.
That is until 2016, when he took part in tests led by Gregory Clark, associate professor of biomedical engineering at the University of Utah’s College of Engineering. These tests seek to electrically connect the user’s remaining arm nerves and muscles to a sophisticated artiﬁcial arm called Life Under Kinetic Evolution, or LUKE. Made by DEKA Research & Development Corporation, the arm is named after Luke Skywalker, who lost a hand in a light saber duel in the Star Wars classic The Empire Strikes Back. U emeritus professor of biomedical engineering Richard Normann and colleagues have developed a neural interface called the Utah Slanted Electrode Array (USEA) that functionally joins the volunteer’s severed nerve ending to the LUKE arm.
“Our job is to connect the arm to the person so they can move it just by thinking about it,” Clark says. And by communicating back a sense of touch and movement, he notes, the limb feels real. In essence, their brain tells them they have their arm back.
The U’s multidisciplinary team—drawing on neuroengineers, materials scientists, electrical and computer engineers, surgeons, and rehabilitation specialists—has been pushing the boundaries of the relationship between human and technology under the umbrella of the Department of Defense-funded program Hand Proprioception and Touch Interfaces (HAPTIX), with additional support from the National Science Foundation.
Beckstead was the fourth of seven volunteers, all amputees. After U hand surgeon Douglas “Hutch” Hutchinson implanted two USEAs, each with 100-point electrodes, into Beckstead’s nerves, researchers hooked him up to a computer to see if he could manipulate a virtual hand with his mind. While lab technicians busied themselves, Beckstead thought about bending his pinkie, then his thumb, then his ﬁnger, only for the screen hand to respond to his thoughts. One of the technicians looked over his shoulder, wide-eyed. “Is that you?”
The resultant hullabaloo among Clark’s team made Beckstead marvel at never having seen so many people get so excited in all his life. “I was the first person in the world to control the hand they’re working on, on the screen,” he says, with the same passion and pride similarly expressed by the other volunteers who have helped turn the Skywalker arm from prosthesis to dexterous hand.
"THEIR BRAIN TELLS THEM THEY HAVE THEIR ARM BACK."
THE GIFT OF ONESELF
Losing a hand is akin to losing a family member, one volunteer told Clark. “Emotionally, to get back the sense that their hand is actually alive again—which is something we can begin to do—is very, very meaningful to them,” Clark says.
“If we can give them some sensation, then they start to feel it’s theirs and they’ll use it,” adds Hutchinson.
With each volunteer, each piece of the puzzle, Clark and his team get ever closer to reuniting people with, in some senses at least, their own hand, although it’s far more than that. “I want people to have their sense of self restored, to feel whole again,” Clark says.
In 2015, the U received the ﬁrst part of a $4.8 million federal grant that funded the most recent round of testing, carrying the neural interface program from virtual reality to volunteers testing a wireless arm both in the lab and on campus grounds. The involvement of U amputation rehabilitation specialist Christopher Duncan focused in part on “taking them from basic science, watching a computerized hand on a screen moving through a range of motions, to real space.” He began by printing 3-D open-source hands and implanting sensors that meant volunteers could start to control the prosthetics with their thoughts. These accomplishments were a bridge to the LUKE hand, says Clark. The team has high hopes for the impact of the HAPTIX program. Duncan recalls how one double-amputee hadn’t felt anything with his hands in 20 years.
The volunteer had withdrawn from society to a nocturnal life of video games, which he played with his toes. But as he spent more time at the lab, “we saw him blossom,” says Duncan. “He was positively ecstatic he could feel things.”
As Keven Walgamott talks about the accident that claimed his left hand, he repeatedly massages the end of his arm where the hand was amputated. The Twin Falls, Idaho-born realtor was pulling a submersible pump out of a 20-foot well on his property when an arc of electricity from overhead high voltage lines struck his pole as he raised it. The electricity went in through his left hand, through his body, blew half his left foot off, and knocked him unconscious.
His prosthetist recommended him for Clark’s studies. “I thought it would be helpful if they could improve the prosthesis,” Walgamott says. “I don’t wear one now because it’s so impractical.”
After Hutchinson implanted several arrays of electrodes into the nerves and muscles in his forearm that help control the hand and wrist, Walgamott underwent tests in Clark’s lab. His amputated left arm was hidden on one side of a small barricade, but he was able to control one of Duncan’s 3-D printed hands, which was in front of him.
Once the experiments for the day concluded, Suzanne Wendleken, a student researcher, asked Walgamott if there was anything he’d like to do. “I’d like to clasp my hands together,” he said.
Clark’s ears pricked up. Not clasp the prosthetic—but “my hands.” Walgamott reached out with his intact biological hand and gripped the prosthetic. “I really felt like it was my hand,” he recalls. “For a split second, it was remarkable to be able to clasp hands again.” In the second half of Walgamott’s 14 months with the lab, the team brought in the LUKE arm and conducted the tests all over again, but this time with the more advanced LUKE arm electrically connected to Walgamott’s motor and sensory systems. He was the ﬁrst person to try the sensorized LUKE arm this way. “Not only did it move, but I felt things when I touched them, too. I hadn’t felt anything on my hand in 12 years,” he says. Walgamott turned to his wife, and she took his left hand—his LUKE hand—and shook it. Perhaps more than any other volunteer, he highlighted that “what you do when you love somebody, you touch them,” adds Duncan.
ON THE CHOPPING BLOCK
Perry Pezzarossi’s contribution to HAPTIX began in late August 2017, when his primary doctor in Louisiana referred him to U of U Health to ﬁnd an answer to the chronic pain in his right hand. For many years, since shattering his wrist in 1993 on active service, he had been forced to live with excruciating pain. He faced one solution, albeit not one he wanted to act on: amputation. Pezzarossi met with Clark, and the researchers connected the LUKE arm to him.
His wife handed a ball to the LUKE hand, and Pezzarossi tossed it back to her with his thoughts—even though his biological hand couldn’t move because of his shattered wrist. “That’s it,” he said. “Chop and swap. I’m in.” Because he lived out of state, U researchers hadn’t been considering Pezzarossi as a possible test subject. In addition, unlike the six previous volunteers who had lost their hands a decade or more before their involvement, Pezzarossi still had to go through the removal of his damaged hand before he could participate. “If I prevent one person going through what I have, then I win,” he says.
Hutchinson amputated Pezzarossi’s right hand to help reduce his chronic pain and make it possible to attach a conventional prosthetic arm. He implanted three electrode arrays in Pezzarossi’s arm nerves and 32 electrodes in his remaining forearm muscles. Pezzarossi’s long disuse of his broken, twisted hand, its aberrant movements (called dystonia), and arm-muscle atrophy all raised questions for the research team about how soon he would be able to control the arm post-surgery. They needn’t have worried. “He was very successful, right off the bat,” Clark says, controlling up to 16 different ﬂexion and extension movements of a virtual arm.
"I FELT THINGS WHEN I TOUCHED THEM. I HADN’T FELT ANYTHING ON MY HAND IN 12 YEARS."
Ultimately, “Perry was able to accomplish multiple sophisticated activities of daily living both inside and outside the lab.” Three months post- surgery, Pezzarossi started wearing the LUKE arm, quickly learning he’d have to retrain his brain to use it. “It doesn’t feel like this feels,” he says, holding up his left hand. “I had to learn what the new feeling was going to be. It’s tough, it’s great, but it’s not easy.” In total, Pezzarossi had implants for a record 17 months, the ﬁrst of the volunteers to use the LUKE arm beyond the lab’s conﬁnes. When he tested the hand under supervision outside the campus lab, he said,“I’m thinking ‘OK, it’s real, it can really happen. I’m proving right now it can be done.’ ”
While Clark and his team await approval from the U.S. Food and Drug Administration to begin testing a new wireless version of the program that would allow volunteers to take the LUKE arm home, those who’ve helped to bring HAPTIX to this point inevitably wonder what their life would be like if they had their own LUKE arm. Like many others, Walgamott says he doubted a dexterous prosthetic arm would be accessible in his lifetime and hoped at least future amputees would beneﬁt. But when he got to brieﬂy test the arm in the lab, he did things he hadn’t been able to do for years, such as pulling on a pillowcase and hammering a nail. He marvels,“These things are closer than I ever knew they were.”
Then he expressed something Pezzarossi and Beckstead also wanted passed along. “If they need another volunteer, please contact me again.”
About the author: Stephen Dark is a writer for University of Utah Health.