MILWAUKEE. Wisconsin (AP) -- A man who was barely conscious for nearly 20 years regained speech and movement three years ago because his brain spontaneously rewired itself, growing tiny new nerve connections to replace the ones sheared apart in a car crash, doctors say they now can prove.
The Arkansas man, 42-year-old Terry Wallis, is thought to be the only person in the United States to recover so dramatically so long after a severe brain injury.
Although his progress is exciting and inspiring, doctors said the same cannot be hoped for people in a persistent vegetative state. Nor do they know how to make others with less serious damage recover, as Wallis did.
"Right now these cases are like winning the lottery," said Dr. Ross Zafonte, rehabilitation chief at the University of Pittsburgh Medical Center. "I wouldn't want to overenthuse family members or folks who think now we have a cure for this."
He had no role in the research, which 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, New Jersey.
Results were published Monday in the Journal of Clinical Investigation.
Wallis was 19 when an accident gave him 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," said Dr. James Bernat, a neurologist at Dartmouth-Hitchcock Medical Center.
Nerve cells that have not died can form new connections; for example, nerves in the arms and legs can grow about an inch (2.5 centimeters) 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 imaging available only in research settings -- not ordinary hospitals or rehabilitation centers -- to establish this.
It tracks the direction of water molecules in and around brain cells, an indicator of brain activity, and makes pictures in red, green and blue -- one color for each direction of movement (up/down, back/front, top/bottom).
"It's a roadmap of how the connections are running," Schiff explained.
Doctors compared Wallis' brain function with 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," evidencing many abnormalities compared with 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 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, Henning 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.
"It's the sort of case that ought to be studied in great depth and I compliment the investigators for doing that," Bernat said. "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. So it's really extraordinary."
Wallis needs help eating and cannot walk, but his speech continues to improve and he can count to 25 without interruption. He has complete amnesia about the two decades he spent barely conscious, but remembers his life before the accident.
"He still thinks Ronald Reagan is president ... and up until recently, he has insisted that he's 20 years old," his father, Jerry Wallis, said in a statement distributed by Cornell.
"One new thing is that he's now able to joke -- that was something he wasn't able to do early in his recovery. He now seems almost exactly like his old self. And he very often tells us how glad he is to be alive."