An amputee can feel his wife’s hand using advanced prosthetic technology after signing up for an experimental research project.
Brandon Prestwood lost his left arm in 2012 He was reassembling an industrial conveyor belt as part of a maintenance crew when someone turned it on His arms were dragged off, and his bones were crushed. After four years of using the hook, Prestwood volunteered for an experimental research project funded by the Department of Defense and Veterans Affairs, he told 60 Minutes correspondent Scott Pell.
Now, Prestwood controls an advanced prosthetic arm with his thoughts. Electrodes, implanted in muscles in his arms, pick up his brain’s electrical signals for movement. A computer translates those signals into the hand. Plastic finger sensors are connected by computer to nerves in his arm to return a rudimentary sense of touch, which he can demonstrate with his eyes closed.
“It just doesn’t feel like my right arm. It’s a tingling sensation,” Prestwood said. “It’s not painful. It’s kind of like, if your hand is asleep, right at the end, right before you wake up… for me, it’s pleasant, it’s a pleasant tingle.”
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Biomedical Engineer Dustin Tyler Case led the research at Western Reserve University and the Cleveland VA Tyler first attempted an artificial connection in 2012. He turned it on as a volunteer and wondered what would happen.
“So I was worried, is it going to be his whole arm? Is it going to be painful? Is it not going to feel anything? We had no idea,” Tyler said. “So, one of those big moments in my career was, he comes in, we turn on the first stimulus, and he stops for a second and he goes, ‘That’s my thumb. That’s the tip of my thumb'”
Seventeen years ago, the Department of Defense launched a $100 million project Revolutionize prosthetics. Slimane Bensmaiah of the University of Chicago is one of the world’s leading experts in the neuroscience of touch. In 2008, when he joined the Defense Department’s prosthetics project, he didn’t think the Pentagon knew what it was up against.
“The brain has 100 billion neurons interconnected with 100 trillion synapses,” Bensmaiah said. “I mean, the human brain, it’s like the most complex system in the known universe.”
He believed that targeting electrical stimulation to exactly the right neuron was too complicated and the stimulation would not be effective, but he was proven wrong by his own research with volunteers, including Scott Imbrie.
Imbry’s movement and sense of touch are limited by a spinal cord injury from a car accident. Computer ports in Imbry’s skull are connected to the motor and sensory parts of his brain. The electrodes receive electrical signals from the brain that were meant for muscles, and a computer translates those signals into the robotic arm.
Ten years ago, Scott Pelley reported on robotics Prosthetics that can be moved with the mindBut there was no sense of touch. Later, Bensmaiah, in collaboration with a team of researchers at the University of Pittsburgh, successfully demonstrated that, using a brain-machine interface, they could not only connect a person to an artificial arm controlled by their mind, but connect it. Sensors in the prosthesis that could be fed back into the participant’s brain produced touch sensations that felt like they were coming from their own hands.
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There are challenges. Eventually, the brain builds scar tissue over the implant, limiting the motor electrodes. But one patient’s implant lasted more than seven years. Imbry has been working for two years. He believes that his experience as a subject of study is the most meaningful work of his life.
“I wanted someone else to have a chance to be free again,” Imbrie said.
The greatest freedom cannot be artificial at all. This wonderful possibility is becoming a reality. Austin Begin became a quadriplegic after an accident during vacation within weeks of graduating from college. Begin’s brain impulses are transmitted through a computer implanted in his own arm that fires his muscles, stimulating movement.
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Motor and sensory impulses flow through ports in his skull and a computer, bypassing his damaged spinal cord. Case Western Reserve University biomedical engineer Bolu Ajiboye led the study.
“Our goal is to restore full arm function, including efficient hand function and reaching ability so that Austin and others who have suffered severe spinal cord injuries can, you know, regain some level of functional independence.” Dr. Ajiboye.
Amazing progress is coming fast. Prestwood’s next device will replace some cables with Bluetooth connectivity. This experimental rig and surgery cost an estimated $200,000, but a final commercial procedure could cost significantly less while delivering precious moments, such as his wife regaining feeling in her hand with a prosthesis. Prestwood told Scott Pele that feeling meant the world to him.
“I was a whole person again,” Prestwood said.