GWEN IFILL: Next, some gee-whiz technology that's changing lives for people with serious disabilities.

NewsHour science correspondent Miles O'Brien tells the story.

AMANDA BOXTEL, Berkeley Bionics: I'm stable, confident, feeling tall.

MILES O'BRIEN: There's a lot of pain and sadness behind that stubborn smile. Nineteen years ago, Amanda Boxtel took a bad fall skiing, never to walk again, until now. Amanda is among the first paraplegics to try her legs as a test pilot on a sophisticated exoskeleton called eLegs. It allows her to stand tall and walk.

It's not about speed?

AMANDA BOXTEL: No, it's not about speed at that moment. I mean, yes, I would love to be able to have the run mode working. And I would -- they wouldn't be able to catch me. I would run out of this building and keep going.

New Generation of 'Bionic' Body PartsTakes Shape

(LAUGHTER)

MILES O'BRIEN: The eLegs got to Amanda on the backs of some able-bodied soldiers. The Pentagon funded the research and development to make it possible for troops to hike longer and faster while carrying much more.

Life imitating art? "Iron Man" fan and Berkeley Bionics CEO Eythor Bender hopes to have eLegs available to take home in three years, selling for about $50,000. He marvels at how technology has marched toward this moment. He says it feels like the computer revolution of the '70s.

EYTHOR BENDER, Berkeley Bionics: There is -- the technology is coming together, just like semiconductors and so on were happening in the early '70s, and software and so on happened at that time. Suddenly, just this is possible.

MILES O'BRIEN: But how? V.P. of engineering John Fogelin explained it to me.

These are the batteries.

JOHN FOGELIN, Berkeley Bionics: Yes, that's right.

MILES O'BRIEN: And this is the actual commuter here?

JOHN FOGELIN: That's right.

MILES O'BRIEN: The computer takes in data from sensors on the knees, hips, arms, and on tip of the crutches, and then decides if it's OK to take a step.

JOHN FOGELIN: The computer acts as a -- has veto power. I mean, if you say -- Amanda could say, give me a step, but if there's something that's not really a particular -- the machine will not instigate a step.

MILES O'BRIEN: So these small steps are really a giant leap in the burgeoning world of bionics, that is, the fusion of biology and electronics.

ACTOR: Steve Austin, astronaut.

MILES O'BRIEN: You remember when you likely first heard that word, right?

ACTOR: We can rebuild him. We have the technology. We can make him better than he was.

MILES O'BRIEN: So we're talking about the $6 million man, right?

DEAN KAMEN, DEKA Research and Development Corporation: The thing they got most wrong was the cost.

MILES O'BRIEN: Inventor Dean Kamen of Segway fame is helping push an explosion in the world of bionics.

So, want to put a price tag on what it will be?

GLEN LEHMAN: Well, accounting for the inflation of the world of science fiction, $6 billion man is probably closer to what will have been spent on these various devices.

MILES O'BRIEN: He is focused on this amazing bionic device, an artificial arm brimming with actuators, batteries and silicon that creates 10 powered degrees of freedom and comes a lot closer to a human arm than the body-powered split-hook devices that were the only prosthetic option for arm amputees for so many years.

Kamen calls his arm Luke, a nod to this scene from the Star Wars series. But, of course, the real thing doesn't measure up to the silver screen science fiction.

GLEN LEHMAN: I don't know anybody today that would say, yes, I would rather have your arm than the original equipment. We're not there yet.

Almost every physical capability you have in your body, there's some actuator that can do it better. And I think those systems will eventually become part of people in prosthetic devices that they either wear or have embedded. And that will just be the natural progression of technology.

MILES O'BRIEN: Kamen's arm is also funded by the Pentagon. The goal? To improve the lives of wounded warriors, people like Glen Lehman, who lost his right arm in a grenade attack in Iraq in 2008.

You didn't know much about the state of the art of prosthetics beforehand, right?

GLEN LEHMAN, Iraq veteran: I had no idea. I'm the first arm amputee I have ever met.

MILES O'BRIEN: But he's an expert now and one of only 50 amputees in the world who can do this simply by thinking about it.

All right, so what did you do to make it do just that?

GLEN LEHMAN: I thought about lifting my arm up, just like you would think about raising your arm or lowering your arm.

MILES O'BRIEN: It's that natural?

GLEN LEHMAN: It's that natural.

MILES O'BRIEN: Lehman can perform this magic after undergoing breakthrough surgery called targeted muscle reinnervation, pioneered here at the Rehabilitation Institute of Chicago by Dr. Todd Kuiken.

DR. TODD KUIKEN, Rehabilitation Institute of Chicago: The idea of targeted reinnervation is that, even though we lose our arm, the nerves that used to go to the arm are still there. And they carry motor command signals to tell the arm what to do.

MILES O'BRIEN: The first person to get the surgery in 2001, double amputee Jesse Sullivan, had the nerves that controlled the basic function of his arm attached to his chest muscles. So, when he thought about moving his missing arm:

DR. TODD KUIKEN: The signal is sent down and a piece of the chest muscle contracts. When the chest muscle contracts, it emits a little bit of electricity called an EMG signal. And we can record that with little antennas or electrodes over the muscle.

MILES O'BRIEN: The electrodes detect the tiny electrical current. They are linked to a computer in the arm which moves the actuators.

DR. TODD KUIKEN: The key thing is to be able to control even what we have got. No one has made wrist flexors until recently because we never had a way to control them.

MILES O'BRIEN: And now you can.

DR. TODD KUIKEN: Now we can.

MILES O'BRIEN: But what if you could eliminate the nerves and the muscles altogether, and tap directly into the brain to control a bionic limb?

That is what this monkey is doing here at the University of Pittsburgh. Tiny electrodes are implanted in his brain that can detect when neurons are firing. Dr. Andrew Schwartz is trying to decipher the patterns of brain activity related to arm movement in order to make better bionic limbs.

DR. ANDREW SCHWARTZ, University of Pittsburgh: So the monkey is going to draw an oval. And you will see that as he goes up with his hand, the neuron fires.

MILES O'BRIEN: These observations are fed into a formula or a model that essentially translates the language of the brain into something a computer understands, making it possible for the monkey to move a robotic arm the same way he would move his own: by thinking about it.

Eventually, Schwartz would like to make the link between mind and mechanical arm a two-way street.

DR. ANDREW SCHWARTZ: And, eventually, we're going to take the information that's being transduced at the fingertips and feed it back to the brain.

MILES O'BRIEN: So it really could give someone who is missing a limb some time in the distant future a sense of touch.

DR. ANDREW SCHWARTZ: That's right.

MILES O'BRIEN: Wow.

Schwartz will soon begin trials on humans with paralysis, as they have here at Brown University, where those tiny electrodes were implanted in the brains of a handful of paralyzed people, making it possible for someone who is shut in to move a mouse or a wheelchair just by thinking about it.

John Donoghue leads the so-called BrainGate study. His long-term goal? To bypass the robotics entirely.

JOHN DONOGHUE, Brown University: We envision that this technology will one day go to a point where we will rewire people and cause it -- and allow them to have their brain signals hooked back up to their body, controlling their own muscles.

And if it's all implanted inside the body, we know that those people will be able to carry out certain functions without you detecting that they have any kind of technology on them at all.

MICHAEL CHOROST, "World Wide Mind": So, it's a very profound process to actually have something inside the body.

MILES O'BRIEN: Partially deaf since birth, Michael Chorost, lost all of his hearing 10 years ago in the span of four hours. Within month, his brain was implanted with cochlear implants, computers that decipher sound into signals his brain could detect and he could comprehend. The experience prompted him to write "World Wide Mind," which explores the melding of mind and machine. But count him skeptical.

MICHAEL CHOROST: I think there is a lot of misplaced optimism at this point. And what I mean by misplaced optimism is the assumption that we will soon and easily be able to replace all damaged and disabled body parts. There is no reason in principle why that can't be done, but science fiction makes it look like it's easy. And it's not.

MILES O'BRIEN: In the meantime, people like Kathy Blake will gladly take what science and technology can provide.

KATHY BLAKE, Artificial Retina Study subject: When I don't have the glasses on, I really don't see anything.

MILES O'BRIEN: She is one of about 40 people in the world with bionic eyesight. A camera in the glasses gathers the image. It gets fed into a small computer, which sends a wireless signal to tiny electrodes implanted on the retina. They stimulate the remaining nerve cells, sending the visual images to the brain. And that literally means fireworks on the Fourth of July for Kathy Blake.

KATHY BLAKE: I'm almost speechless. When I saw the fireworks, I was really just mesmerized watching it, just not believing that I could actually see that.

MILES O'BRIEN: So, what happens to our humanity as we equip our bodies with all these manmade parts?

Dr. Mark Humayun of USC leads the team that is pushing this bionic vision technology.

DR. MARK HUMAYUN, University of Southern California: I think, instead of us becoming more machines, what these machines do is actually make us more human. And, in fact, one of our patients told us that, that this device allows me to integrate more, to be able to play with my grandson, and it allows me to be more human.

MILES O'BRIEN: Or is it superhuman? Indeed, the prosthetic limbs South African sprinter Oscar Pistorius wears are so advanced, he faces accusations he has an unfair advantage as he petitions to compete in the 2012 Olympics.

AIMEE MULLINS, paralympian: It's about people throwing off the shackles of history saying that some people are less than.

MILES O'BRIEN: Aimee Mullins was among the first double amputees to successfully compete in NCAA Division 1 sports. She ran track at Georgetown. She says those carbon cheetah running legs are no different than carbon golf clubs, titanium bicycles, or LASIK surgery. All of it can improve human performance.

AIMEE MULLINS: There is no such thing as a level playing field in any sport.

MILES O'BRIEN: But where nature or misfortune has taken something human away, humans may be on the verge of finding ways, not just to replace what is lost, but to do better, just like "The Bionic Woman" or "The Six Million Dollar Man."

AIMEE MULLINS: And that music would come on, that slow-most, and, you know, seeing her leap over, you know, fences, and him being on the operating table with that somber voice-over saying, "We can rebuild him," I -- it's like, yes, we can.

(LAUGHTER)

AIMEE MULLINS: And, of course, I had my wooden legs at the time with a big leather cuff, and nothing technologically sexy at all. But -- but I knew it was possible. And it is now. It's becoming possible.

MILES O'BRIEN: Dean Kamen recently made Aimee some high-tech swim fins that would let her leave other athletes in her wake.

So, who is abled and who is disabled? Is she more, or less, or superhuman? And how can I get some fins like that?