Scuba diving could raise hope for the paralyzed

A new study maybe giving hope to people with paralysis. Researchers found that patients had improved feeling and function after they'd been scuba diving. CBS News contributor Dr. Sanjay Gupta looked into this latest development.

Cody Unser seemed to have a storybook childhood. She was a natural athlete with a famous father, former racecar driver Al Unser, Jr.

It ended when she was 12.

"I went down to touch my left leg and it was numb," she told "48 Hours" in 1999. "I looked to my mom and said, 'What's happening to me?'"

Unser was diagnosed with transverse myelitis -- a disease that causes the immune system to attack the spinal cord. She was paralyzed from the chest down.

Early on, one thing gave her freedom from her wheelchair was scuba diving.

"It's so liberating and so freeing down there," Unser, now 24, said. "My body just feels so -- I don't know, I feel like I'm flying."

"You also noticed something else, right in terms on your own body?" Gupta asked her.

"Oh, yeah."

"What else were you starting to notice?"

"I was starting to notice some sensation in my legs."

Unser was so sure those sensations were from the scuba, she convinced her neurologists at Johns Hopkins and Kennedy Krieger Institute to study it.

"This is brand new," said Dr. Daniel Becker, a neurologist at the Kennedy Krieger Institute. "It has not been done, and that's why there is no comparison."

Becker and neurologist Adam Kaplin took Unser along with ten paralyzed veterans on a four-day dive trip to the Cayman Islands. All were tested for motor control and sensitivity to pinprick and touch before and after diving to depths of more than 60 feet -- a depth where the pressure on the body is nearly triple normal atmospheric pressure on the surface.

"Almost all of the subjects got stronger after going diving," Becker said. "It completely blew us out of the water."

"I thought, 'This is kind of odd,'" said Unser, "and it lasted for about three weeks. It wasn't just in the water and then it went away as soon as I got up on the surface."

At those depths, nitrogen builds up in the bloodstream. Researchers say the leading theory is that nitrogen accumulation in the subjects' tissues, as a result of repeated dives, may increase levels of the chemical serotonin in their central nervous systems. That might jump start nerves in the spine without input from the brain.

"There could be a back door into reactivating sort of circuitry that already exists in the spinal cord," said Kaplin. "You just have to be able to go back and find the right way to stimulate it to regain some function and re-teach it how to work again."

"The study will help create something that's much larger than myself," said Unser. "I would love to walk again and put my feet in the sand."

If results can be repeated in larger studies, researchers believe it could open up a whole new avenue of research for helping paralyzed patients regain function, outside of things like electrical stimulation and stem cell transplants. In fact, this Hopkins team believes Cody may -- in her lifetime -- feel her legs and be able to feel that sand in her toes as she talked about.

CBS Evening News anchor Scott Pelley asked Gupta what other neurologists have said about this research.

"I think a lot of them were somewhat skeptical initially," said Gupta, "thinking that scuba diving could actually cause this regain of function. Now they recognize it appears to be true, figuring out 'What's the delivery mechanism here?' 'What exactly is causing it?' and 'How do you replicate that?' Obviously, you're not going to take people on scuba diving trips all the time. But there is something specifically with the nitrogen for example -- 'Can you deliver that in a different way?' That's where they sort of went ahead with this."

For more information, visit these links:

Cody Unser First Step Foundation:www.cufsf.org
Kennedy Krieger Institute: www.kennedykrieger.org
University of Central Florida: www.ucf.edu
Christopher Productions: www.christopherproductions.org