Patient in a vegetative state 'talks' to scientists

Dr Owen said: 'We were astonished when we saw the results of the patient's scan.

'Not only did these scans tell us that the patient was not in a vegetative state, but, more importantly, for the first time in years it provided the patient with a way of communicating his thoughts to the outside world.'

He said fMRI scanning was an expensive tool but in future, computer devices might help patients to communicate whether they needed pain relief or would like to try new drugs.

He said: 'Just for patients to exercise some autonomy is a massive step forward.'

Dr Nicholas Schiff, a neuroscientist at the Weill Cornell College in New York, said the work 'changes everything'. He said: 'These findings have extremely broad implications for concerns about the accurate assessment of patients in custodial care situations.'

Chris Frith, Emeritus Professor of Neuropsychology, University College London, said: 'It is difficult to imagine a worse experience than to be a functioning mind trapped in a body over which you have absolutely no control.

'We have the distinct possibility that, in the future, we will be able to detect cases of other patients who are conscious and what's more, we will be able to communicate with them.'