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."

The new study calls the whole field of sleep research into question.

"People don't think they get enough sleep and they get less sleep than they think," said Diane Lauderdale, associate professor of health studies at the University of Chicago and an author of the new study.

Other studies have indicated that average sleep time declined from 9 hours in 1900 to 7 hours in the 1970s, and that things have gotten worse ever since as modern life has become more hectic.

"Our study tells that we can't entirely trust those earlier surveys," Lauderdale said, "because people do not know how much they sleep."

Sleeping patterns varied among the participants:

* White women: 6.7 hours a night
* White men: 6.1 hours
* Black women: 5.9 hours
* Black men: 5.1 hours

The results are detailed in the July issue in the American Journal of Epidemiology.

Average sleep duration in the new study is "remarkably lower" than values reported in most previous studies, writes Stuart Quan of the University of Arizona in a commentary of the research for the journal.

Lack of sleep has been linked to:

* Reduced ability to concentrate
* Decreased attention to detail
* Increased risk of motor vehicle accidents
* Medical problems, including obesity, diabetes and hypertension

The study was supported by the
National Institutes of Health, a federal agency.

A mutation in the CK1 gene, called the tau mutation, had been thought to slow the gene's activity, allowing the body clock to speed up.

But researchers in Michigan and Utah now report that the mutation speeds up the body clock by increasing the activity of the gene rather than slowing it.

"The key to developing treatments for problems like depression and insomnia - disorders influenced by circadian rhythm - is being able to predict how the body's internal clock can be controlled," Dr. David Virshup of the University of Utah's Huntsman Cancer Institute said in a statement.

Virshup and Daniel Forger of the University of Michigan were co-lead authors of the report.

A protein called PER helps set the body's biological clock and the researchers studied how fast PER degraded in cells.

The theory had been that the tau mutation would cause PER to build up more quickly. But when they tested the idea in mouse cells the circadian rhythm sped up as the CK1 gene became more active and PER disappeared more quickly than normal.

Funding for the study was provided by the National Institutes of Health, the Huntsman Cancer Institute and the Sloan Foundation.

"This shows there's no substitute for a healthy lifestyle," said Stephanie Chiuve, lead author of the study to be published in Circulation: Journal of The American Heart Association.

The study tracked 43,000 men between 40 and 75 who were free of diabetes, heart disease and other chronic conditions when the study began in 1986. They completed biannual questionnaires and researchers used the data to tease out correlations between heart disease and lifestyle habits.

The benefits of the healthy habits were apparent even if they were adopted over time.

"In other words, it's never to late to change," said Chiuve. "You can still achieve benefits if you make changes in middle age or later in life."

Men with the lowest risk of heart disease were those who practiced all five healthy habits, but not smoking alone reduced the risk of heart problems by 50 percent, she said.

Jenny Greenberg, the group's director, suggests funding the Innocence Initiative as a state-supported, autonomous law office to protect clients' privacy. She won't say how much she is seeking, saying any amount would help. The group is operating on a $214,000 private grant this year.

"Every politician says there's no more important issue," said Greenberg, one of two paid employees. "We aren't getting a penny" from the state.

The Innocence Initiative didn't ask the Legislature for money this year for fear of jeopardizing a bill to eliminate deadlines for when prisoners can request DNA testing, she said.

The measure passed this spring and was signed earlier this month by Gov. Jeb Bush. However, since the bill also made some changes that will now prevent the Initiative from requesting federal dollars, state support might become even more important.

Bush said he'd consider a request from Greenberg.

Florida gives nonprofit organizations across the state money every year, a spokeswoman for the state's financial services department said. Greenberg already has a list for how the Initiative would spend the money.

First, hire another staffer to help respond letters from prisoners across the state. Already, 800 letters line Greenberg's office like wallpaper. Most of these letters will only warrant a brief reply, she said. Others will launch record searches that cost hundreds of dollars but lead to dead ends. Some, the golden ones, could trigger new DNA testing that helps an innocent prisoner clear his name from behind bars.

Second, launch a search for other innocent prisoners.

"Innocent prisoners should not be looking for us," Greenberg said. "We should be looking for them." She wants to set up a statewide network of workers who search for innocents among Florida's estimated 88,000 prisoners - many of whom can't read and don't know what DNA testing is, she said.

Third, offer rehabilitation services to wrongfully convicted prisoners. They're not like other inmates, who serve a full sentence or are paroled and thus eligible for post-jail counseling, Greenberg said. Rather, they live in a no-man's-land, left alone to deal with their trauma.

"Not being believed when you tell the truth is a deep, deep wound," Greenberg said. "It doesn't heal."

Not all Florida's criminal justice experts agree with funding the Innocence Initiative. Instead, they say, prisoners should turn to the system they're already in.

"I really think that our system, even though it's not perfect, is pretty much geared over to defendants," said Willie Meggs, the state attorney in Leon County. Defendants who can't afford private lawyers can get help from one of Florida's 20 public defender's offices - five of which help inmates with appeals.

Plus, prosecutors themselves are on the side of innocent people, he said.

"I don't know of a single solitary attorney who wants to put an innocent person in jail," Meggs said. "We're the first ones to step up to the plate if we find information that establishes a person's innocence."

Skip Babb, president of Florida's Public Defender Association, said he thinks Greenberg's idea is great - but unrealistic.

"Can you say, 'Never gonna happen?'" he said. "We've had to fight so hard for the funds we get in the public defender's office, they're (legislators) not about to fund anything else."

Florida has about 1,300 assistant public defenders, lawyers who start at $38,500 and sometimes represent 200 clients at a time. They could sure use the help, he said.

"It would be another level of assurance that innocent people aren't in jail," Babb said. "It would be a luxury to have that, but to get the Legislature to fund that would be a monumental task."

With or without more funds, Greenberg said she and her staff will keep working - it's the only way she can sleep at night.

"I'm doing what I can do," she said. "So long as I can say that, I have to be all right."