A man presumed to have been in a coma for 23 years has spoken of his “second birth” after doctors realised that he had been fully conscious all along but unable to communicate.

Rom Houben (46) was paralysed in a car accident that left him in what doctors thought was a persistent vegetative state. In fact he remained aware of his surroundings and could hear medical staff gradually giving up hope.

Researchers using new scanning techniques discovered that his brain was still active and trained him to use his right forefinger to express himself on a specially adapted keyboard.

His case is being highlighted in his native Belgium by doctors who are pioneering new ways of understanding coma victims, hundreds of whom could be conscious but locked in paralysis and, unlike a true coma patient, able to feel pain.

“I shall never forget the day when they discovered what was truly wrong with me, it was my second birth,” Mr Houben tapped out on his custom-built keyboard at the nursing home east of Brussels where he is given care.

“All that time I just literally dreamt of a better life. Frustration is too small a word to describe it.”

Mr Houben, an engineering student and martial arts expert, had been written off as in an “extinct” state after he was seriously injured in a car crash in 1983.

He “woke up” three years ago thanks to coma specialists at the University of Liege.

He recalled the terrifying realisation that he had lost complete control of his body but no one knew that he was fully conscious.

“I screamed, but there was nothing to hear,” he said.