For 23 torturous years, Rom Houben says he lay trapped in his paralysed body, aware of what was going on around him but unable to tell anyone or even cry out.
The car crash victim had been diagnosed as being in a vegetative state but appears to have been conscious the whole time. An expert using a specialised type of brain scan that was not available in the 1980s finally realised it, and unlocked Mr Houben's mind again.
Mr Houben, 46, is now communicating with one finger and a special touchscreen on his wheelchair.
"Powerlessness. Utter powerlessness. At first I was angry, then I learnt to live with it," he said, punching the message into the screen during an interview with the Belgian RTBF network, aired on Monday. He has called his rescue his "renaissance".
"I would scream, but no sound would come out,'' he said. "I will never forget the day they finally discovered what was wrong - it was my second birth.''
He could hear what was being said around him throughout but was unable to respond.
"I became the witness to my own suffering as doctors and nurses tried to speak to me and eventually gave up," he said.
Cut off from the world, he passed his time in thought.
"I dreamed of a better life all the time. Frustration is too small a word to describe what I went through," he said.
"I want to read, to talk to my friends with the computer and to live life now people know I'm not dead."
Over the years, Mr Houben's family refused to accept the word of his doctors, firmly believing their son knew what was happening around him and gave no thought to letting him die, his mother, Fina, said.
She was vindicated when the breakthrough came.
"At that moment, you think, 'Oh, my God. See, now you know.' I was always convinced," she said.
The discovery took place three years ago but only recently came to light, after publication of a study on the misdiagnosis of people with consciousness disorders.
While a 23-year error is highly unusual, the wrong diagnosis of patients with consciousness disorders is far too common, said the study, led by Steven Laureys of Belgium's Coma Science Group.
"Despite the importance of diagnostic accuracy, the rate of misdiagnosis of vegetative state has not substantially changed in the past 15 years," the study said.
Back then, studies found that "up to 43 per cent of patients with disorders of consciousness are erroneously assigned a diagnosis of vegetative state".