Persistent Vegetative States

From an article by Ian Sample in The Guardian titled "For first time, doctors communicate with patient in persistent vegetative state":

A 23-year-old woman who has been in a vegetative state since suffering devastating brain damage in a traffic accident has stunned doctors by performing mental tasks for them. Brain scans revealed that the woman, who has shown no outward signs of awareness since the accident in July last year, could understand people talking to her and was able to imagine playing tennis or walking around her home when asked to by doctors. The discovery has astounded neuroscientists who believe it could have dramatic implications for life and death decisions over other patients diagnosed as being in a persistent vegetative state (PVS)... "This is extremely important. It's the difference between life and death. From cases in the UK and the US, we know that end-of-life decisions are of course extremely important and this will definitely change the way we deal with these patients. When you have signs of consciousness, you cannot decide to stop hydration and nutrition," said Steven Laureys, a neurologist at the University of Liege and co-author of the study which appears in the journal Science today... Persistent vegetative state was first described in 1972 by Scottish and American neurologists and only came to medical attention because of extraordinary advances in keeping severely brain-damaged patients alive for longer. Neurologically, the condition is a slight improvement on a coma. Patients diagnosed as PVS show no signs of consciousness or awareness, but unlike those in a coma, have periods of sleep and wakefulness and periodically open their eyes. The condition is a source of huge controversy in medical and legal fields, largely because of the difficulty in proving a patient is unaware and the extreme difficulty in predicting whether a patient will ever recover. Adults typically have a 50% chance of recovering from a persistent vegetative state within the first six months, but after a year, the chances of recovery drop dramatically. Those who recover after longer periods usually experience serious disabilities. The mysterious condition continues to confound scientists. In May, a team of British and South African doctors announced they had given sleeping pills to a PVS patient to help calm restless movements at night. The patient woke up 15 minutes later and was able to speak and even tell jokes. Doctors have kept the patient on the pills, and believe it works by acting on part of the brain that had been shut down in response to the patient's original trauma.