A man in a deeply unconscious state for five years has been able to communicate with doctors using just his thoughts in a study scientists say is a "game changer" for care of vegetative state patients.
British and Belgian researchers used a brain scanner called functional magnetic resonance imaging to show the man, who suffered a severe traumatic brain injury in a road accident in 2003, was able to think "yes" or "no" answers to questions by wilfully changing his brain activity.
Experts say the result means all patients in coma-like states should be reassessed and it may change the way they are cared for in future.
After detecting signs of awareness, the doctors scanned the man's brain while he was asked to say "yes" or "no" to questions such as "is your father's name Thomas?". The results showed that by changing his brain activity, the man communicated his answer.
"We were astonished when we saw the results of the patient's scan and that he was able to correctly answer the questions that were asked by simply changing his thoughts," said Dr Adrian Owen, co-author of the study from the Medical Research Council. "Not only did these scans tell us that the patient was not in a vegetative state but, more importantly, for the first time in five years it provided the patient with a way of communicating his thoughts to the outside world."
Dr Owens said the research raised a number of ethical issues.
"The interesting philosophical point is what it says about consciousness. If you sit in a chair and do nothing, I have no way of knowing that you are conscious. Patients like this must always have existed, and more are bound to be detected in the future, but we've never been able to identify them before," he said. "This man has done everything that you or I are able to do, at least within the parameters of what we have tested. We can't say that he's not completely conscious.
"Obviously this fits into the issue of when patients should be allowed to die, and I imagine data like this will be used in that context before long. However there are a number of really important things to consider. One is that just because somebody can say 'yes' or 'no' does not mean they have the cognitive wherewithal to make complicated decisions about their destiny," he said.
"It's quite a leap to say 'let this patient decide whether he lives or dies"'
Dr Owen said he hoped to see fMRI used as a diagnostic tool for brain damaged patients within three years. At present the technique was confined to research labs.
The man, now 29, was one of 23 patients diagnosed as being in a vegetative state who were scanned using functional magnetic resonance imaging (fMRI).
The scans detected signs of awareness in four of the patients, the researchers wrote in their study published in the New England Journal of Medicine yesterday.
The fMRI method used can decipher the brain's answers to questions in healthy people with 100 per cent accuracy, but it has never been tried before in patients unable to move or speak.
Nicholas Schiff, a neurologist from Weill Cornell Medical College in New York, said the findings were a "game changer" that could "have a profound impact across medicine".
In comments sent by email, he said the results called for the reassessment of all patients currently in so-called "minimally conscious" or "vegetative" states.
A bitter right-to-die row erupted in the United States in 2005 over the fate of Terri Schiavo, a 41-year-old woman who had been in a vegetative state since a heart attack in 1990.
Her case went back and forth through the US courts and even prompted then president George W. Bush to intervene as her husband fought for doctors to halt feeding and let her die.
Experts say traumatic brain injury can heal better than injury from stroke or heart attack, such as Ms Schiavo suffered.
A similar case in Italy involved a comatose woman whose father had battled for 10 years to have her feeding tube disconnected. Eluana Englaro died last year.
Reuters