JOHN YANG: Roughly 300,000 people in the United States have suffered spinal cord injuries,
life-changing events with far reaching-effects.
But, as William Brangham reports, new research out of the University of Louisville is giving
dozens of paralyzed people the prospect of regaining some of what they have lost.
It's part of our series Breakthroughs on the Leading Edge of science.
WILLIAM BRANGHAM: For the last 10 years, this is the only way Kent Stephenson has been able
to get around.
He has a severe spinal cord injury, no feeling or movement below his chest.
So, what you're about to see is something that shouldn't be possible, because doctors
told him his legs would never work again.
And yet, today, he's back on his feet, struggling and straining to relearn how to take steps
again.
Let's back up.
In 2009, Stephenson was a semi-pro motocross rider.
But one day at practice, he took a jump, his bike seized up, and he crashed.
As he was rolled into the hospital on a gurney, he got a glimpse of a future he'd never imagined.
KENT STEPHENSON, Suffered Spinal Cord Injury: Opened my eyes, and you could see the ceiling,
and it was metal, and you could see the reflection of myself.
And that was when it really hit me, because one of my boots was still on for some reason.
I don't know why they didn't take it off, but I was like, oh, boy, I cannot feel that.
WILLIAM BRANGHAM: Stephenson had destroyed two vertebrae in his back.
Doctors said he'd be in a wheelchair for the rest of his life.
His career was over.
KENT STEPHENSON: I mean, that was my dream since I was little, was to go do that, race
that pro circuit and do all that.
And it was -- I mean, it was like, heck, yes, let's go, because everything was in place,
and then everything changed that day.
WILLIAM BRANGHAM: But, in 2010, he enlisted in an experimental research program at the
University of Louisville.
The traditional view has been that when someone like Stephenson has such a bad injury, the
signal between his brain and his spinal cord is permanently severed.
But Susan Harkema -- that's her in red -- directs spinal cord injury research at the University
of Louisville and the Frazier Rehab Institute.
She wondered whether there was more to it than that.
SUSAN HARKEMA, University of Louisville: When a person has a spinal cord injury, as devastating
as that is, it's only where the bone is broken that the neurons die.
But there's millions of neurons below that are still alive and can function under the
right conditions.
And then we know all the neurons in the brain are still there.
It's just that communication network that's broken.
WILLIAM BRANGHAM: Harkema and her colleagues ran a series of experiments using what's known
as an epidural stimulator, a device typically used to treat pain.
Implanted near the base of the spine, it delivers a small electrical current.
They wanted to test the idea that this current could restore some of that spinal communication.
But when Stephenson got his implant, he thought the whole thing sounded pretty far-fetched.
I know, the whole time, you're just thinking, like, come on, guys, we know what the answer
of this is.
KENT STEPHENSON: Yes.
WILLIAM BRANGHAM: It ain't going to happen.
KENT STEPHENSON: You know, the little gremlin over here on my shoulder, yes, he's like,
what are you -- you're wasting your time.
WILLIAM BRANGHAM: That was, until something remarkable started to happen.
This video is from 2011.
That's Stephenson there.
He'd just had his stimulator implanted.
Remember, he hadn't moved his lower body in years.
But now he's going to try.
KENT STEPHENSON: Up.
Down.
WOMAN: Awesome.
KENT STEPHENSON: Oh, man, I mean, it was -- my mom was in the room.
And I was there.
We got all eye-watery and everything.
I mean, I was like, oh, boy, you know, now what?
Where's this going to go, you know?
(LAUGHTER)
KENT STEPHENSON: Because I have just been told from day one that you just traumatically
injured your spinal cord.
It's done.
You know, there's nothing.
WILLIAM BRANGHAM: Harkema acknowledges she too was stunned at these results.
She and her colleagues don't exactly know how or why this all works.
The theory is, even with the most severe spinal injuries, some pathways remain intact, and
the stimulator helps amplify the signal from the brain through the spine to the limbs.
Then, to augment this effect, they use intense physical therapy to recreate what it physically
and mentally feels like to walk again.
SUSAN HARKEMA: You put weight back on the legs, you get them extended, you get the trunk
upright, and the spinal circuitry says, oh, I know what that is.
That's standing.
I know how to do that.
And then the circuits for standing relearn again.
WILLIAM BRANGHAM: Nearly two dozen others have been implanted with stimulators through
this program.
Twelve are now able to stand upright with support.
Two have been able to walk assisted over flat ground.
One managed to walk nearly a quarter-of-a-mile, with breaks, over the course of an hour.
Other programs in Switzerland and the Mayo Clinic in Minnesota have produced similar
results.
Of course, it's all easier said than done.
Training, in many cases, takes more than a year.
Marissa Kirkling has had her implant since last summer.
After a car accident last year left her paralyzed below the chest, she too had been told this
would never happen.
WOMAN: One, two, three.
WILLIAM BRANGHAM: She's in the early days of learning to stand again.
And she's the first to admit it's really hard.
MARISSA KIRKLING, Suffered Spinal Cord Injury: You have to be thinking.
As I keep talking, I kind of get a little off -- focused off my legs.
I'm losing them.
WILLIAM BRANGHAM: So, am I distracting you here?
Should I go away?
MARISSA KIRKLING: No, you're OK.
WILLIAM BRANGHAM: She's got to concentrate on every single muscle, her posture, where
her feet are, not to mention answer my questions.
MARISSA KIRKLING: Before my accident, you know, you don't have to really think.
Like, you're standing there right now.
You don't have to think, oh, squeeze your glutes, toes up, heels to the floor.
WILLIAM BRANGHAM: So, you're thinking all those thoughts right now?
MARISSA KIRKLING: Yes.
I am, like head up straight, neck back, shoulders back, yes, so -- because if you don't think
about them, you're going to -- I'm going to buckle.
WILLIAM BRANGHAM: But the benefits for her go beyond standing.
Spinal cord injuries also impair some people's ability to regulate their blood pressure.
Kirkling says hers would drop so suddenly, even getting out of bed was a challenge.
MARISSA KIRKLING: Then you pass out, and then it's like you're out, and then you just come
back.
And then you just have to try again.
WILLIAM BRANGHAM: And that would happen several times during an average day?
MARISSA KIRKLING: Yes.
Yes.
It's just -- you could be at the grocery store or the mall shopping, just sitting there watching
a movie.
It doesn't matter.
WILLIAM BRANGHAM: But the epidural stimulator also improves this function.
Now Kirkling is off most of her blood pressure medications, and she can get through most
days without passing out.
She's also regaining her ability to sing, something else her accident robbed her of.
Of course, there are still plenty of other open questions.
Dr. Ali Rezai is a neurosurgeon and director of the Rockefeller Neuroscience Institute
at West Virginia University.
DR.
ALI REZAI, West Virginia University: It's interesting and it's exciting, but there's
a lot of constraints that we need to look at, in terms of, not every -- it doesn't work
in everybody.
So we have got to understand, why is it?
I think being able to just get rough movements is very exciting, no doubt, but we need to
translate that into functional, practical applications.
WILLIAM BRANGHAM: Beyond that, Rezai says, there's the issue of scalability.
DR.
ALI REZAI: A lot of these studies across the world have large teams, neurosurgeons, neuroscientists,
neurologists, dozens of people.
And the patients have to come to the hospital or to the clinic.
We need to translate that to the home.
WILLIAM BRANGHAM: Harkema acknowledges this research is still just the tip of the iceberg.
SUSAN HARKEMA: We need to look at the process differently right now.
Regardless of epidural stimulation, whether it should be a treatment or not, we know people
can recover.
I mean, that's clear.
WILLIAM BRANGHAM: For Kent Stephenson and his wife, who were babysitting their niece
when we visited, it's meant dreams of an expanding future.
KENT STEPHENSON: One of my questions right out of the gate in the back of my mind was,
can I have kids?
You know, the physical fitness that I have gotten back from being part of the stimulator
program, it gives me that instillment that I could be, you know, the utmost father that
I was going to be before or after injury.
WILLIAM BRANGHAM: For Marissa Kirkling, it not only means the possibility of one day
standing and walking on her own, but regaining the ability to do something she loves.
(SINGING)
WILLIAM BRANGHAM: For the "PBS NewsHour," I'm William Brangham in Louisville, Kentucky.