It seemed to be a medical miracle: the car crash victim assumed for 23 years to be in a coma who was suddenly found to be conscious and able to communicate by tapping on a computer.

The sceptics said it was impossible – and it was. The story of Rom Houben of Belgium, which made headlines worldwide last November when he was shown to be "talking", was today revealed to have been nothing of the sort.

Dr Steven Laureys, one of the doctors treating him, acknowledged that his patient could not make himself understood after all. Facilitated communication, the technique said to have made Houben's apparent contact with the outside world possible, did not work, Laureys declared.

"We did not have all the facts before," he said. "To me, it's enough to say that this method doesn't work." Just three months ago the doctor was proclaiming that Houben had been trapped in his own body, the victim of a horrendous ­misdiagnosis, and only rescued from his terrible plight thanks to medical advances.

At that time Houben was pictured using the technology, which involves a speech therapist being guided by a patient to write words using a keyboard. A basic test appeared to prove it was indeed Houben who was communicating. "I shall never forget the day when they discovered what was truly wrong with me," Houben apparently tapped. "It was my second birth. I want to read, talk with my friends via the computer and enjoy my life now that people know I am not dead."

"Just imagine," he purportedly typed. "You hear, see, feel and think, but no one can see that."

Laureys, leader of the coma science group and department of neurology at Liege University hospital, said a study he had done of three speech therapists working with minimally-conscious patients showed that in two cases, including Houben's, facilitated communication failed. "From the start, I did not prescribe this technique. But it is important not to make judgments. His family and care­givers acted out of love and compassion," he said.

The turnaround vindicates those doctors who had doubted Houben's apparent ability. "It's like using an Ouija board," said Arthur Caplan, a professor of bio­ethics at the University of Pennsylvania. "It was too good to be true, and we shouldn't have believed it."

Facilitated communication can be used with some patients but should be avoided with patients such as Houben who are severely brain injured, said Tom McMillan, a professor of neuropsychology at Glasgow University. "It has an inter­mediary who can exert control and that can affect the outcome," he said.