Brain activity detected in patients in vegetative states

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The World's Rhitu Chatterjee reports on a new study by British and Belgian scientists that suggests that some patients in a ?vegetative state? retain some level of consciousness.

KATY CLARK: A new study by British and Belgian scientists has raised provocative questions about the inner life of patients in what doctors call a vegetative state. They're seemingly unconscious or unaware. The new research published online by the New England Journal of Medicine suggests that some of these patients can respond to simple "yes" and "no" questions with their brains. The World's science correspondent Rhitu Chatterjee explains.

RHITU CHATTERJEE: The patients in the study had all suffered severe brain injuries. Neuroscientist Adrian Owen of Britain's Medical Research Council says the patients could involuntarily open and shut their eyes, but they appeared to be permanently unconscious

ADRIAN OWEN: They'd had had all sorts of clinical tests and assessments to verify that they were vegetative. And on that basis, the assumption is that they are entirely unaware of their current circumstances and anything that may be going on around them.

CHATTERJEE: But Owen wanted to look deeper for signs of consciousness. So he decided to use a technology called Functional Magnetic Resonance Imaging or fMRI. It enabled scientists to detect tell-tale patterns of activity in the brain when people perform specific mental tasks.

OWEN: When you perform a mental task like imagining making a movement or imagining going from place to place, areas of the brain that are involved in those processes will require more oxygen delivery and we can pick that up with the MRI machine. And it will appear as bright blobs on the brain.

CHATTERJEE: So Owen and his team devised a clever experiment. They asked the seemingly unconscious patients simple "yes" and "no" questions. They told the patients to respond yes by for instance thinking about playing tennis. They could respond no by imagining themselves walking from room to room in their own homes. In healthy people, these two different tasks light up different regions of the brain. Now, for the vast majority of the 23 patients in the study the experiment yielded nothing interesting. It showed no sign that they could understand the questions or respond to them. But Adrian Owen says that wasn't the case for four patients.

OWEN: The patients could activate the area of the brain precisely when we asked the to do so and they could keep activating it until we asked them to stop. So we were very sure that people were completely in control of this brain activity. So they weren't vegetative at all.

CHATTERJEE: Owen emphasizes that it's not clear how conscious these patients are or whether their brains are capable of complex thought. But the study raises a host of difficult questions. Have some people supposedly in vegetative states been misdiagnosed? Might it be possible some day to communicate with these patients about whether they want to be kept alive?

GEORGE ANNAS: The real question is not how it's going to change diagnosis, it's how it's going to prognosis.

CHATTERJEE: That's George Annas, a Bioethicist at Boston University.

ANNAS: What are the long-term consequences of being in what looks a persistent vegetative state, but actually having some minimal activity in your brain? Does that mean that you might be able to recover more activity in your brain while you're locked into that small activity? In which case, we really haven't changed the decision-making of what should be done with these patients.

CHATTERJEE: That question: What should be done with such patients, how long they should be kept alive has long been a point of controversy both in the US and abroad. The new study in itself can't answer that question, but it may offer some valuable new tools. Doctors can now probe inside the brains of people who were otherwise thought to be unreachable, and perhaps some day find out what they're thinking. For The World, I'm Rhitu Chatterjee