We don’t often think about how the sense of touch makes our lives possible. We grip a paper coffee cup with perfect force but do not crush it. Our feet always find the floor. But for those with prosthetic limbs, or those with spinal cord injuries, the loss of touch can put the world beyond their grasp. Seventeen years ago, the Department of Defense launched a $100 million project To revolutionize prosthetics. The robotics you’re about to see is amazing—but even more remarkable is how people like Brandon Prestwood are returning to ‘feelings’.
Brandon Prestwood: For me, it was a battle if I wanted to live or die.
Scott Pele: You weren’t sure you wanted to live?
Brandon Prestwood: No. I didn’t know if I wanted to or not.
Brandon Prestwood’s battle began with the loss of his left arm. In 2012, he was on a maintenance crew reassembling an industrial conveyor belt when someone turned it on.
Brandon Prestwood: And my arm was pulled up to the shoulder. It crushed my bones in my arm and fed through my arm with about an inch gap.
Scott Pell: How did they save your life?
Brandon Prestwood: Other maintainers jump in. They basically start taking the machine apart. Once we took it apart, I could look and see what was in there. And one of the gentlemen was a Vietnam veteran…
SCOTT PELLE: And the Vietnam veteran knew what to do.
Brandon Prestwood: Yeah.
The Vietnam veteran knew the tourniquet, but Prestwood lost his hand and could not return to his job.
After four years on the hook, he told his wife, Amy, he wanted to volunteer for experimental research on surgery at the VA.
Amy Prestwood: I wasn’t 100% to begin with. But I knew he had his mind set that he was– he had to do it. And I couldn’t hold him.
Six years later, thanks to Department of Defense and VA projects, Prestwood controls this hand without his thoughts.
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Lab tech: Everything still looking good?
Brandon Prestwood: Maybe, when I get him around here…
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 attached to nerves in his arms to return a rudimentary sense of touch that he can demonstrate with his eyes closed.
Biomedical Engineer Dustin Tyler Case led the research at Western Reserve University and the Cleveland VA
Dustin Tyler: Touch is really about connection, connection to the world, it’s a connection to others and it’s a connection to yourself, right? I mean, we never experience not being touched. It is the largest sensory organ in our body.
In 2012, Tyler first attempted an artificial connection He started it as a volunteer and wondered what would happen
Dustin Tyler: So I was concerned, would it be his whole arm? Will it be painful? Won’t it feel something? We had no idea. So, one of those big moments in my career is he comes in, we turn on the stimulus first, and he stops for a second and he goes, “That’s my thumb. That’s the tip of my thumb.
Scott Pelley: What happened at this moment?
Dustin Tyler: First time.
Scott Pell: It didn’t require any brain training.
Dustin Tyler: No. That was the beauty of it, “My Thumb.”
Brandon Prestwood remembers the moment that happened to him.
Brandon Prestwood: “It’s my finger.” I feel my fingers that I don’t have anymore. I feel them.
A certain feeling, he told us, but different.
Brandon Prestwood: It just doesn’t feel like my right hand. It’s a tingling sensation. It is not painful. It’s kind of, if your hand is asleep, right at the end, right before you wake up, to me it’s pleasant, it’s a pleasant tingle.
A jerk that’s light to the touch but gets stronger the harder he presses. With eyes closed, he can pinch a cherry hard enough to pull it from its stem but not crush it.
I had to use my lightest touch with bare eggshells.
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Scott Pelley: So if I hold it here–
Brandon Prestwood: I can feel it. I feel it here and here.
It feels more than a decade in the making.
Scott Pell: At the beginning of this research, how did you imagine that this would be possible?
Slimane Bensmaiah: I never imagined. I imagined it would not be possible.
Slimane Bensmaiah, of the University of Chicago, is one of the world’s leading experts in the neuroscience of touch. In 2008, he joined a Defense Department project to revolutionize prosthetics but didn’t think the Pentagon knew what it was up against.
Slimane Bensmaiah: The brain has 100 billion neurons interconnected with 100 trillion synapses. I mean, the human brain, it’s like the most complex system in the known universe.
Too complicated, he believed, was to aim electrical stimulation at just the right neurons.
Sliman Bensmaiah: And when we electrically stimulate, we activate hundreds, thousands at the same time, in a way that would never happen naturally. It seemed that a very poor interface with this nervous system would never do anything–be able to do anything useful. And it turns out I was wrong.
He has been proven wrong by his own research…
Scott Imbry: How are you Scott, nice to meet you.
Scott Pelley: Nice to meet you, Scott.
…with volunteers including Scott Imbrie
Scott Pele: And you can feel it?
Scott Imbry: I feel it in my fingertips.
…whose 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. Electrodes pick up electrical signals from the brain that were meant for muscles. A computer translates those signals into the robot arm.
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We saw it first Brain/Machine Interface Ten years ago at the University of Pittsburgh. But, then there was no more sensation.
Scott Imbry: Index finger…
In collaboration with Pitt, neuroscientist Slimane Bensmaiah showed that touch signals can be relayed back to the brain.
Scott Pelley: How do you possibly know which part of the brain the tip of the index finger is?
SLIMAN BENSMAIA: We took Scott and we put him in a scanner, a functional magnetic resonance imaging scanner. And then we visualize him moving his thumb, imagine moving his index finger, imagine moving his digits as we monitor his brain activity. And lo and behold, the sensory and motor parts of the brain that are involved with the hand, lit up.
There are challenges. Eventually the brain builds up scar tissue on the implant that limits the motor electrodes. But one patient’s implant lasted seven years. Scott Imbry has been working for over two years.
Scott Pelley: You’ve been a subject of this work for years now. And I wonder why.
Scott Imbry: I wanted someone else to have a chance to be free again.
Scott Pelle: Most meaningful work of your life?
Scott Imbrie: Yes, sir. 100%
The greatest freedom cannot be artificial at all. And we saw this wonderful possibility with a pioneer, Austin Begin. His brain impulses are not directed at the robot, but at the implant in his own arm that fires his muscles.
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Scott Pell: What function did you have in this hand before the implant?
Austin Begin: Oh, not at all.
Scott Pele: Nothing? Can’t you move it at all?
Austin Begin: No. So, all I can really do is shrug my shoulders and shift them a bit. Unfortunately, this is what came back after my accident.
Her accident was on a vacation celebrating her college graduation. A dive into a submerged sandbar left him a quadriplegic. Now, motor and sensory impulses flow through ports in Begin’s skull and a computer, bypassing his damaged spinal cord.
Case Western Reserve University biomedical engineer Bolu Ajiboye led the study.
Bolu Ajiboye: Our goal is to restore full upper arm function and reach ability with efficient hand function so that Austin and others who suffer from, you know, severe spinal cord injuries can regain some degree of functional independence.
The swing under his arms only supports the weight – all motion is his own. It takes effort. He must concentrate on—
Computers require frequent adjustments. But his parents Shelly and Brad have shown us where that can lead.
Begin retained limited sensation following his injury, making him ideal for evaluating the prosthetic sense of touch. His motor skills continue to improve.
Austin Begin: So if I could expand first. Let me open my arms for you and squeeze around it. You’ll feel me start to really dig in there.
Scott Pelley: You have a gripe.
Austin Begin: Yes. (laughs) It really is. And let go and I will bring back the hand.
Scott Pelley: Congratulations.
Austin Begin: Yes. Thank you. thanks–
Scott Pelley: Amazing.
Austin Begin: — a lot.
Amazing progress is coming fast. Danny Warner lost his leg in Vietnam. But 47 years later, he was reattached to touch a prosthetic leg that helps him balance, climb stairs and walk on uneven ground. Brandon Prestwood’s next device will replace some cables with Bluetooth connectivity. His experimental rig and surgery cost an estimated $200,000. But a final commercial system can cost significantly less while delivering priceless moments.
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Scott Pelle: What does it mean to feel Amy’s hand in yours?
Brandon Prestwood: The world. I am whole again. I don’t have to worry about those dark thoughts.
Amy Prestwood: It gave me back my husband who means the world to me. He is himself again.
‘Self’ because the sense of feeling is what makes us human. Maybe that’s why, when we see a tender moment, it’s called “touching.”
Brandon Prestwood: I love you.
Produced by Aaron Wiese. Associate Producer, Ian Flickinger. Broadcast Associate, Michelle Karim. George J. Edited by Garcia.
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