A Belgian man who doctors thought was in a coma for 23 years was conscious all along, it has been revealed.
Medical staff believed Rom Houben had sunk irretrievably into a coma after he was injured in a car crash in 1983.
The University of Liege doctor who discovered in 2006 that, although Mr Houben was paralysed, his brain was working, said the case was not unique.
Mr Houben said that at first he felt angry at his powerlessness, but eventually learned to live with it.
"Other people had an opinion of me," Mr Houben, now 46, told the BBC.
"I knew what I could do and what I was capable of but other people had a rather pathetic image of me. I had to learn to be patient and now finally we are on an equal footing."
'He's an optimist'
It was only in 2006 that a scan revealed Mr Houben's brain was in fact almost entirely functioning.
He now communicates by using a special keyboard attached to his wheelchair.
His mother, Fina Houben, told the BBC that she always believed her son could communicate.
"He is not depressed, he is an optimist," she said. "He wants to get out of life what he can."
The BBC's Dominic Hughes, in Belgium, says the case raises the issue of how many other people believed to be in comas are actually trapped inside their bodies, desperate to communicate.
Mr Houben's story was revealed in a paper written by Steven Laureys, a doctor at Liege University.
In it, Mr Laureys said that in about 40% of cases in which people were classified as being in a vegetative state, closer inspection revealed signs of consciousness.