EDITOR'S NOTE: Some of the scientific findings discussed in this story have subsequently been revised. For an updated story, please click here .

For half of his life Rom Houben, 46, had to listen to people say that he was as good as dead. At first, doctors would occasionally bend over him and wave their hands in front of his eyes, but because his gaze remained unresponsive, they eventually gave up. Caregivers would plead for some indication that he knew they were there -- a wink or a squeeze of the hand. But they too gave up after a while. Diagnosis: addressing him was pointless. There was no one home.

A former martial artist and engineering student, conversant in four languages, Houben was now wheelchair-bound, his body crooked and helpless. After his car accident, he became a creature that could just barely breathe, swallow and digest food, but was otherwise believed to be an empty shell of a human.

But the whole time, Houben was conscious -- and no one knew.

How did you survive those 23 years, Monsieur Houben? The man in the wheelchair makes a deep growling noise. He appears to be pondering the question. Suddenly his right index finger rattles swiftly across the keyboard attached to his armrest, and words appear on a monitor, one letter at a time. "I meditated, I dreamed that I was somewhere else," he writes. "And please call me Rom."

The man who became lost to his surroundings now lives in an attractive nursing home in Zolder, a town in northwest Belgium. He is still almost completely paralyzed, but he is capable of a small amount of movement in his right hand, which he uses to communicate. With the help of a speech therapist, who stands behind him and supports his hand, Houben can now write on an on-screen keyboard.

'My Second Birth'

His finger rattles across the screen again, as he writes: "I will never forget the day they discovered me, the day of my second birth."

It was a lucky coincidence. Steven Laureys, a Belgian neurologist, had heard about the case. Laureys, who heads the Coma Science Group at the University of Liege, had long suspected that many patients who are in a coma are in fact conscious, at least intermittently, but that their awareness goes undetected. But even Laureys had rarely encountered such an extreme case of doctors failing to recognize that a patient believed to be in a coma was in fact conscious. When Laureys pushed the man from Zolder into an MRI tube, large areas of the brain were lit up on the monitor. The cerebrum, with its gray matter, was apparently only slightly damaged, leading Laureys to the conclusion that the mind of the man in the seemingly empty shell of a body was in fact largely intact.

How could all of the people who had treated and cared for Houben have failed to notice this for so long? Laureys attributes this to a fault in the system. "Once someone is stamped as being 'not conscious,' it becomes very difficult to get rid of that label."

After his car accident, Houben was classified as a hopeless case, a coma patient in what is called a persistent vegetative state (PVS). Such patients have their eyes open, but they do not react consciously to their environment. Experts are relatively sure that they do not even feel pain. Their prospects of recovery are considered slim to nonexistent.

But this diagnosis is sometimes wrong. In fact, Laureys and his team have already uncovered dozens of such cases, and expensive tomography brain scans are not always necessary. As a recent study has shown, taking a thorough look at the patient is often all it takes.

Remnants of Consciousness

Laureys and his team of researchers examined 103 coma patients in Belgian clinics and nursing homes. Of those, 44 were considered clearly vegetative by their caregivers. However, the study reached a completely different conclusion: In reality, 18 of these 44 patients were in fact responsive, and there was evidence that remnants of consciousness were stirring in their brains.

The alarming conclusion is that more than 40 percent of PVS patients are incorrectly diagnosed as hopeless.

This is not necessarily the result of sloppiness on the part of the medical community. In the cases uncovered by the Laureys team, all of the doctors, nurses and speech therapists were convinced of the accuracy of their diagnosis. Shortly before performing their tests, the researchers asked the medical team to agree on the condition of the patient in question. The patient was then re-examined within 24 hours, but only if the medical team's conclusions were unanimous.

The researchers used a series of tests that systematically search for indications of consciousness. The patients must complete a number of tasks. For example, they are asked to look into a mirror that is being moving slowly in front of their faces. They are also asked to grasp a comb placed near one of their hands. In another test, a researcher claps his or her hands loudly behind the patients to see whether they turn their heads toward the source of the noise.

Involuntary Reflex?

The procedure can take hours. In addition, it should be repeated at various times of the day, because many PVS patients drift in and out between an awake and dreamlike state. It is important to catch them when they happen to be present.

It is rare for anyone to take the time necessary to perform this battery of tests. Even experts, as Laureys' study showed, often reach their conclusions much too quickly. If a patient happens to apply pressure with his hand later on, they tend to dismiss this as an involuntary reflex with no further significance.

But there is a great deal at stake. In patients who are in a vegetative state, the cerebral cortex, the center of higher mental function, is in fact completely destroyed. Other than good nursing care, there isn't much else that can be done for these patients. But it's a different story when parts of the brain are still active. Such patients sometimes respond when addressed, but they cannot communicate in an organized fashion. The parts of their brain that are still intact are no longer sufficiently connected, which explains why their minds flicker sporadically, but unreliably. Neurologist Laureys calls this a minimal state of consciousness.

A person in this state appears to understand some things. If a familiar voice tells a story taken from the patient's life, the neural networks for speech processing become active. More importantly, however, minimally conscious patients remain receptive to pain, even if they are unable to show this. "That's the key difference," says Laureys. "They have to be given painkillers when they need them. But that usually doesn't happen."

This is also a problem in Germany, where the medical community doesn't even differentiate between a vegetative and a minimally conscious state. As long as patients are being cared for in a clinic, this isn't necessarily harmful, because effective caregivers observe their patients to see, for example, whether they begin to sweat or grimace during a tracheoscopy. If that's the case, the patients are given painkillers until they relax again.

Overdosed

However, most PVS patients live in nursing homes or with their families. As a result, a doctor in private practice is usually the person responsible for alleviating their ailments, from back pain to spastic cramps, which are often chronic. "However, many are not qualified to cope with these patients," says Andrea von Helden, the chief physician at the Center for Patients with Severe Traumatic Brain Injury at the Vivantis Hospital in Berlin. "Most of them simply dispense with pain medication altogether."

Some coma patients, on the other hand, are routinely given doses of pain medication that are much too high -- because it's practical. "They are so drugged that they can't even wake up anymore," says Helden, who once took on an apparently unconscious patient who in fact was under a permanent overdose of anti-epileptic drugs. The dosages had hardly been corrected before the patient gradually returned to life. "The man lives at home now, and he can walk and speak," says Helden. "The nursing homes need to be combed through looking for such cases."

In Germany, about 100,000 people a year sustain severe traumatic brain injuries, of which roughly 20,000 remain in a coma for more than three weeks. Some of them die, while others regain their health. But an estimated 3,000 to 5,000 people a year remain trapped in an intermediate state: they are alive, but they never quite return to full consciousness.

'We Always Knew Our Son Was There'

These patients are placed in long-term care facilities, provided their families can afford it. The system has a tolerably good reputation. In the better homes, music therapists perform for the silent residents, rabbits are set out to hop around within their field of vision and, in some places, trained therapy dogs lie with them in bed. These methods are effective, even with the most absent patients. In most cases, their heart rates settle down and their muscle tension diminishes.

With effective care even vegetative patients, as the case of American Terri Schiavo demonstrated, can remain alive for decades. But their fate is more or less sealed. Only 5 percent of PVS patients experience any improvement after a year.

In a minimally conscious state, on the other hand, many things are possible. American Terry Wallis was unresponsive for 19 years before suddenly addressing his mother as "Mom!" When a team of researchers in New York imaged his brain, the results were astonishing: Countless neural pathways had sprouted between the few intact areas of the brain. This enabled these previously isolated islands in the brain to resume contact -- a condition of consciousness.

Of course, no long-term patient has ever been able to walk again -- they all continue to require nursing care. But it is worthwhile to search for remaining sparks of intellect, says Andreas Zieger, a come specialist at the Protestant Hospital in the northwestern German city of Oldenburg. If Zieger had his way, all coma patients in Germany would be thoroughly examined. People with residual consciousness, says Zieger, have a right to receive special support, such as speech therapy, because there is always hope. As scientists know today, the brain is still capable of making minor progress after being severely damaged.

Dying of a Simple Infection

Berlin doctor Helden remembers a patient who fell into a coma two years ago. Today he can swallow on his own again, and he turns his head when his girlfriend walks into the room. "It doesn't seem like much, but it's a tremendous achievement for him," says Helden. "And if no one appreciates the progress these people make, they lose their drive and end up dying of a simple infection."

A persistent vegetative state is also believed to be an emotional drama. When a patient has suffered a shock, his consciousness is shut down in the interest of saving his life. "When that happens, the body must first slowly extend its feelers once again," says Oldenburg expert Zieger. Some nursing homes are so understaffed that they do little to help their patients acquire a taste for life again, and to entice and encourage them. "In those places, they are merely given palliative treatment, and they soon die."