A paralyzed Belgian man who spent the past 23 years incorrectly diagnosed as being in a vegetative state, was fully conscious and could hear everything around him the entire time.
The man, Rom Houben, can finally communicate, thanks to a neurologist's persistent research.
Doctors had assumed the 1983 car crash that paralyzed Houben, now 46, had also put him in a vegetative state -- awake but not conscious of his surroundings.
Houben, a one-time engineering student and martial arts enthusiast was trapped in his own world. That is, until Dr. Steven Laureys of the University of Liege, using modern brain scanning technology unavailable in the 1980s, saw that Houben's brain lit up with near-normal functioning when he was asked a question.
Houben had heard the doctors, nurses and family speaking in his room for decades.
"I shall never forget the day when they discovered what was truly wrong with me -- it was my second birth," Houben told the German magazine Der Spiegel, communicating via a special keyboard.
Laureys discovered Houben' state in a Belgian hospital three years ago, but the case has only just come to light after Laureys published a study in the journal, BMC Neurology earlier this year. Laureys said in recent study of his, "4 out of 10 patients where we thought they were in a vegetative state in reality were not, [they] were minimally conscious."
"In Rom's case, it was very dramatic, because he was fully conscious… so, yes he now can actually tell us how horrible it was and it's hard for us to even imagine what it must be like.... to be conscious yet, cut off from the outside world," said Laureys.
He argued that new imaging technology will show that many more people like Houben, believed in a vegetative state are actually misdiagnosed.
According to ABC News senior health and medical editor Dr. Richard Besser, misdiagnosis can happen fairly easily in the beginning of treatment.
"When you have a major accident, an injury, you can damage the entire brain," Besser told "Good Morning America." "Over time, parts of it can come back. The damage to the outer brain, that gets better [and] they don't do additional testing."
More often than not it's a family member that realizes the patient is not in a vegetative state just from being with them in the room, Besser said.
But until Laureys' research moves out of the experimental phase and into standard testing at hospitals, experts say there may be some rare situations where doctors still miss the signs that someone is completely paralyzed but fully aware.
"If there's anything we've learned in the past couple of years, is that we have to be very cautious about prognosticating; providing a severe prognosis early on," said Dr. Michael DeGeorgia, director of the Neurocritical Care Center at University Hospitals Case Medical Center in Cleveland.
DeGeorgia said determining a person's state of consciousness after a severe brain injury can be a subtle and difficult process, especially shortly after an accident when people are often on heavy pain medication. Now there is an entire sub-specialty of neurology to look at "neurocritical care," but not when Houben was diagnosed.
Without the modern functional imaging technology Laureys used, DeGeorgia said doctors more often relied on a "primitive" test called the Glasgow Coma Scale, a 15-point check list of eye and motor movements in response to questions.