Alex Schadenberg has an excellent post on the man who emerged a 23-year long coma (persistent vegetative state) and the dangers that such a diagnosis presents to patients. He concludes:

Medical professionals need to be far more careful before diagnosing a patient as PVS. If society rejects hypocratic medicine and accepts euthanasia, the time would come where people in PVS would be treated as non-persons, euthanized out of a concept of false compassion or used as an organ donor based on utilitarian ethics. Since approximately 40% of PVS cases are misdiagnosed, and since the PVS diagnosis is often treated like a death sentence, therefore society needs to reject the current paradigm by once again treating people in coma states as human beings deserving of care.

We must reject the dehumanizing of the PVS patient and develop new techniques to offer them new opportunities for recovery.