In 2003, almost 20 years after suffering a severe brain injury during a car accident, Terry Wallis suddenly emerged from what doctors call a "minimally conscious state" -- somewhere between being awake and being in a vegetative state.
Now, researchers believe the "miracle" that allowed the 42-year-old to rejoin the world was actually a very slow process in which his brain grew new connections to heal its injured parts.
What is remarkable about this is that up until now, brain experts did not know to what extent the brain could still heal itself so many years after an injury.
"In essence, Terry's brain may have been seeking out new pathways to re-establish functional connections to areas involved in speech and motor control -- to compensate for those lost due to damage," said Nicholas Schiff, the senior author of a study on brain damage published in the July 1 issue of The Journal of Clinical Investigation.
The study used a combination of new and standard brain imaging techniques to look at the state of Wallis' brain at various points after he became fully conscious.
While technically conscious, he still suffers from complete amnesia. He's convinced that it's still the 1980s, and he can't walk and needs helps eating.
"High-tech brain imaging is suggesting that cells in the relatively undamaged areas of Terry's brain slowly grew important, novel connections over a period of years," said Schiff, who is also the director of the Laboratory of Cognitive Neuromodulation at Weill Cornell Medical College in New York City.
Not too many years ago, conventional wisdom said that the nervous system -- and certainly the brain -- stopped growing once it fully developed during childhood and that it did not regenerate or repair itself.
However, this study confirms there is still a lot to be learned about the brain and its cells, known as neurons.
"Currently, there is very little known about this process," said Joy Hirsch, professor of radiology and psychology in the Center for Neurobiology and Behavior at Columbia University Medical Center in New York City. "This study is a landmark study because of its potential clinical relevance."
Although the goal is to eventually be able to predict which patients have the best chance of recovering consciousness, experts warn that this research is only one step in that direction.
"The brain is the most complicated organ, and trauma is the most complicated injury," said David Hovda, director of the UCLA Brain Injury Research Center. "We need to study multiple patients over time and the same patients at different times in their recovery before we'll be able to predict which patients have the best chance of recovery."
Wallis' Long Ordeal
Wallis was 19 when he was severely injured in an automobile crash. After emerging from a coma -- meaning he had been unresponsive to stimuli -- in the early months following his accident, his doctors determined he would likely spend the rest of his life in a vegetative state. His eyes had opened but he was still unresponsive.
When his parents were told nothing more could be done, they took him back to a nursing home near their Arkansas home, where they helped care for him. His ordeal was showcased in the documentary "The Man Who Slept for 19 Years."
Everyone, to say the least, was utterly surprised when Wallis awoke three years ago and called out the word "mom," asking for the woman who had spent the previous two decades at his bedside.
A New Diagnosis: 'Minimally Conscious State'
When Wallis suffered his injury, the diagnosis "minimally conscious state" did not exist. Experts say it is a fairly new category of consciousness.
"It is defined by evidence at the bedside of some awareness of the environment or self-awareness," Schiff said.
"Patients will respond to sensory stimuli. They may track objects in the room, reliably fixate their eye or respond to auditory stimuli. On the higher end, [they] will respond to commands. [They] may even verbalize or intermittently communicate. But … although they show evidence of conscious awareness, patients are unable to reliably communicate."
Some experts believe it may be a transition stage from unconsciousness to consciousness.
"Usually patients pass through a state of minimal consciousness as they emerge to consciousness," Hirsch said.
Not Quite a Coma, Not Quite Consciousness
There are important distinctions between being in a coma and being in minimally conscious or vegetative states.
While the term "coma" is loosely used by the public to describe any unresponsive state, in clinical terms it occurs early in brain injury.
It is the stage in which a person is unresponsive and the eyes remain closed.
Once the eyes are open, it is no longer a coma. At that point a determination must be made as to whether one has passed into a minimally conscious state or a vegetative state.
"In a vegetative state, patients show no evidence of any response to their environment," Schiff said.
"A vegetative state patient, like a coma patient, is completely unresponsive. They may have some reflex changes when they're pressed with very intense stimuli. … [They] have a period when the eyes open and the eyes close."
Joseph Giacino, one of the study's authors, said that because the minimally conscious state was a relatively new diagnosis, it might not always be so clear-cut for physicians to identify.
"There may indeed be patients who are somewhat conscious who are being misdiagnosed as being in a vegetative state, and thus being shipped off to nursing homes without being given the opportunity, resources, [and] therapy to get better," said Giacino, associate director of neuropsychology at JFK Johnson Rehabilitation Institute in Edison, N.J.
"It's not that doctors are negligent. It's just that it is very difficult to measure consciousness. For example, a patient who doesn't speak, respond to voices, or move their head when spoken to might still have some level of awareness. And, if they do, it is more likely that they will improve in the future."
Giacino said that while Wallis' case of regaining consciousness after almost 20 years was "unbelievably rare," he feared some doctors and insurance companies might be "jumping the gun" and diagnosing a vegetative state too early.
"I think the whole point of this work is to aim at better abilities to identify patients who we can help and figure out ways in which we might be able to help them," Schiff said. "That's the point of the work, and that's where we hope to head with it."
Cathy Becker, medical producer for Good Morning America, contributed to this story.