Seeking Consciousness, Doctors Turn To Brain Scans

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A closeup of a CT scan with brain.
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Dr. Adrian Owen has spent his career studying brain damage as a cognitive neuroscientist and a professor at Western University in Ontario, Canada. His new findings may change the way neuroscientists decide which "vegetative" patients are conscious and which are not—a tactic that may change how countless brain trauma patients are treated all over the world.

"Typically when we talk about a persistent vegetative state, what we mean is a patient who is awake but unaware—they'll open their eyes, they may even seem to look around the room, and they go to sleep at night sometimes," says Dr. Owen. "But they seem to be completely unaware, and by that I mean you cannot attract their attention with a noise, ask them to look at something, or address them in any way and expect a response."

For many years, scientific and medical communities have generally accepted that persons in a persistent vegetative state are completely unaware. But Dr. Owen says that new technologies are shedding light on the brain functions of people in vegetative states. His new, innovative research detects consciousness in unresponsive patients. Rather than asking his patients to physically respond to stimuli or commands, Dr. Owen and his colleagues have used functional magnetic resonance imaging (FMRI) to conduct brain scans and observe activity in the minds of vegetative patients.

"Neuroimaging tools called FMRIs are being used to show that some of these patients have some residual abilities that were simply not detectable at the bedside," says Dr. Owen. "Even though they appear to be unaware, some of them may turn out to have some level of awareness in the FMRI scanner."

Dr. Owen and his team asks his patients to imagine playing tennis or walking around their homes, and then they examine which areas of the brain light up. About 20 percent of patients are responsive.

"When you're trying to establish whether the patient is aware, often you'll say, 'Squeeze my hand,' and the patient may not be able to do it," he says. "We put the patient in the scanner and say imagine this scenario or that scenario. These are scenarios that we know that are linked to particular changes in FMRI activity in the brain."

Dr. Owen says when people are asked to imagine that they are playing a game of tennis, they often picture themselves moving their arms. When visualized, that scenario activates the motor regions of the brain.

"Instead of asking the patient to raise their arm we're asking them to imagine moving their arm," says Dr. Owen. "We can detect that imaginary response. Although it is an imaginary response, it is still a response, and in that sense it can still indicate awareness or some residual awareness because the patient is doing what we're asking them to do—albeit with their brain rather than their body." 

While this research seems cutting-edge, Dr. Owen says that a large majority of patients will respond as a matter of reflex.

"If for example we play the patient speech, we will see activity in the so-called speech areas of the brain—the parts of the brain that we know process language," he says. "We know that doesn't mean that all of these patients understand speech, are processing it, and can respond. It's because the brain's response to speech is an automatic one—you can't turn your brain off from listening to speech."

Dr. Owen and his team have created a hierarchy of neuro-responses to determine what is reflexive or automatic behavior, and what is genuine awareness or consciousness. 

"The higher-level responses where the person is actively generating a brain state occurs really in a much smaller number of patients," he says.

While the number of individuals that are able to respond while in a vegetative state is extremely small, it's not impossible. Dr. Owen says that he and his team were able to connect with a man that has been in a vegetative state for more than a decade. 

"He had been in a vegetative state for 15 years," says Dr. Owen. "This gentleman, we put him into the scanner on many occasions and we actually got into a situation where we were having a fairly regular dialogue. We asked him many questions about his life, his situation. We were able to establish that he knew who he was, where he was, and he knew how long he'd been there. He had attitudes, he had opinions."

While the breakthroughs Dr. Owen describes happen with just a small minority of patients, he says these new findings represent a new period for neuroscience. 

"We're beginning to detect them and we're beginning to enter an era where we may be able to communicate with them on a regular basis," says Dr. Owen. "It may allow them to contribute to their own therapeutic future and make decisions about what happens to them."