A study published on Wednesday reveals that a man who was presumed to be in a vegetative state for the past five years can apparently communicate yes and no via his thought patterns.

In 2003, the man, who is now 29, sustained a severe traumatic brain injury in a road traffic accident. He remained physically unresponsive and was presumed to be in a vegetative state for five years, according to the researchers in Belgium and Britain.

Using functional magnetic resonance imaging (fMRI), the patient's brain activity was mapped while he was asked to answer yes and no questions such as "Is your father's name Thomas?" according to the study results published in the authoritative New England Journal of Medicine.

"We were astonished when we saw the results of the patient's scan. He was able to correctly answer the questions that were asked by simply changing his thoughts, which we then decoded using our fMRI technique," explained Dr Adrian Owen who headed the team from the Wolfson Brain Imaging Centre in Cambridge, England.

The new technique can decode the brain's answers to such questions in healthy, non-vegetative, participants with 100 percent accuracy. But it has never before been tried in a patient who cannot move or speak.

In a three-year study, 23 patients diagnosed as vegetative were scanned in Cambridge and Liege. The new technique was able to detect signs of awareness in four of these cases.