Terry Wallis, right, is shown with his mother Angilee Wallis in his parents home in Stone County, Ark., Saturday July 1, 2006. For the first time, doctors say they have proof the brain can grow its own repairs. Their evidence is Wallis who regained speech and movement after being barely conscious for nearly 20 years. The scientists say Terry Wallis' brain spontaneously rewired itself by replacing the tiny nerve connections that were cut in a car crash. [AP Photo]

Doctors have their first proof that a man who was barely conscious for nearly 20 years regained speech and movement because his brain spontaneously rewired itself by growing tiny new nerve connections to replace the ones sheared apart in a car crash.

Terry Wallis, 42, is one of the few people known to have recovered so dramatically so long after a serious brain injury. He still needs help eating and cannot walk, but his speech continues to improve and he can count to 25 without interruption.

Wallis' sudden recovery happened three years ago at a rehabilitation center in Mountain View, Ark., but doctors said the same cannot be hoped for people in a persistent vegetative state, such as Terri Schiavo, the Florida woman who died last year after a fierce right-to-die court battle. Nor do they know how to make others with less serious damage, like Wallis, recover.

"Right now these cases are like winning the lottery," said Dr. Ross Zafonte, rehabilitation chief at the University of Pittsburgh Medical Center, who was not involved in the research. "I wouldn't want to overenthuse family members or folks who think now we have a cure for this."

Wallis has complete amnesia about the two decades he spent barely conscious, but remembers his life before the injury.

"He still thinks Ronald Reagan is president," his father, Jerry, said in a statement, adding that until recently his son insisted he was 20 years old.

The research on Wallis, published Monday in the Journal of Clinical Investigation, was led by imaging expert Henning Voss and neurologist Dr. Nicholas Schiff at the Weill Medical College of Cornell University in New York City and included doctors at JFK Medical Center in Edison, N.J.

Wallis was 19 when he suffered a traumatic brain injury that left him briefly in a coma and then in a minimally conscious state, in which he was awake but uncommunicative other than occasional nods and grunts, for more than 19 years.

"The nerve fibers from the cells were severed, but the cells themselves remained intact," unlike Schiavo, whose brain cells had died, said Dr. James Bernat, a neurologist at Dartmouth-Hitchcock Medical Center in New Hampshire, who is familiar with the research.

Nerve cells that have not died can form new connections; for example, nerves in the arms and legs can grow about an inch a month after they are severed or damaged. However, this happens far less often in the brain.

The new research suggests that instead of the sudden recovery Wallis seemed to make when he began speaking and moving three years ago, he actually may have been slowly recovering all along, as nerves in his brain formed new connections at a glacial pace until enough were present to make a network.

Researchers used a new type of brain imaging only available in research settings, not ordinary hospitals or rehabilitation centers, to establish the regrowth. It tracks the direction of water molecules in and around brain cells, an indicator of brain activity.

"It's a roadmap of how the connections are running," Schiff said.

Doctors compared Wallis' brain function to that of 20 healthy people and another minimally conscious patient who showed virtually no recovery for six years. All were imaged twice, 18 months apart.

In Wallis' brain, "what we first see is how overwhelmingly severe this injury was," with many abnormalities compared to the healthy people, Schiff said.

The second set of images showed changes from the first, strongly suggesting that new connections had formed. These correlated with areas of the brain that affect the ability to move and talk.

The other minimally conscious patient, a 24-year-old man who suffered a severe brain injury in a car accident when he was 18, also had evidence of changes in nerve connections, but they were not organized in a way that made a difference in his ability to function.

"We'll have to understand more about why recovery occurred" in Wallis' case, Zafonte said. "The question is 'why?' It's not just 'wait.'"

Until that is known, imaging cannot be used to predict who will recover, or to help patients' brains rewire, he said.

The Charles A. Dana Foundation, which finances brain research, funded the scientific work. The lead author, Voss, also received money from the Cervical Spine Research Society, whose sponsors include companies that make spine care products. The British Discovery Channel and HBO paid to fly Wallis and family members to Cornell for tests.

"Most neurologists would have been willing to bet money that whatever the cause of it, if it hadn't changed in 19 years, wasn't going to change now," Bernat said. "So it's really extraordinary."

Wallis' father said his son is now able to make jokes. "That was something he wasn't able to do early in his recovery," Jerry Wallis said. "He now seems almost exactly like his old self. And he very often tells us how glad he is to be alive."