TERRY WALLIS awoke from a coma-like state 19 years after tumbling over a guard rail in a utility and falling nearly 10 metres into a dry riverbed. Now doctors armed with some of the latest brain-imaging technology think they know part of the reason why.While Wallis showed few outward signs of consciousness, his brain was methodically rebuilding the white-matter infrastructure necessary for him to interact with the outside world, researchers reported in the Journal of Clinical Investigation.”I believe it’s a very, very slow self-healing process of the brain,” said Henning Voss, a physicist at Weill Cornell Medical College and head author of the study.
Wallis emerged from a minimally conscious state in 2003 at the age of 39 and uttered his first word: “Mom.” Since then he has regained the ability to form sentences and recovered some use of his limbs, though he still can’t walk or feed himself.
Using positron emission tomography scans and an advanced imaging technique called diffusion tensor imaging, the researchers examined the Arkansas man’s brain after he regained full consciousness. They found that cells in the relatively undamaged areas had formed new axons, the long nerve fibres that transmit messages between neurons.
“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 a study author, Dr Nicholas Schiff, a neurologist at the Weill Cornell Medical College in New York.
He cautioned that Mr Wallis was a “1-in-300 million” case. But Steven Laureys, a neurologist at the University of Liege in Belgium, said the findings would force doctors to reconsider the way they treat patients in minimally conscious and persistent vegetative states.
In a minimally conscious state, a patient shows intermittent signs of awareness but is often unable to interact with the outside world. It is a less severe condition than a persistent vegetative state, in which the patient is awake but has no awareness of herself or her surroundings. Terri Schiavo, the Florida woman at the centre of a bitter right-to-die battle, had been in a persistent vegetative state for 15 years when her husband won a court order to have her feeding tube removed last year.
Neurologists believe the longer a person is in a minimally conscious or persistent vegetative state, the lower the recovery chances. Such patients are often neglected by doctors and insurance companies, Dr Laureys said. In his last few years at an Arkansas nursing and rehabilitation centre, Mr Wallis’s family began to notice that the former mechanic and Ford enthusiast would grunt when a Chevrolet commercial came on the television. They said he answered questions by blinking his eyes.
About two years before he regained full consciousness, he began taking the antidepressant Paxil, which doctors say may have contributed to his recovery. Within a week of his first utterance, Mr Wallis began speaking in simple sentences. Los Angeles Times
Filed under: Other | Leave a comment »