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DR. ADRIAN OWEN: Imagine this scenario. You've unfortunately had a terrible accident. You're lying in a hospital bed and you're aware—you're aware but you're unable to respond, but the doctors and your relatives don't know that. You have to lie there, listening to them deciding whether to let you live or die. I can think of nothing more terrifying.

I'm Dr. Adrian Owen. I'm the author of 'Into the Gray Zone', a neuroscientist explores the border between life and death.

Communication is at the very heart of what makes us human. It's the basis of everything. What we're doing is we're returning the ability to communicate to some patients who seem to have lost that forever. The vegetative state is often referred to as a state of wakefulness without awareness. Patients open their eyes, they'll just gaze around the room. They'll have sleeping and waking cycles, but they never show any evidence of having any awareness.

So, typically, the way that we assess consciousness is through command following. We ask somebody to do something, say, squeeze our hand, and if they do it, you know that they're conscious. The problem in the vegetative state is that these patients by definition can produce no movements. And the question I asked is, well, could somebody command follow with their brain? It was that idea that pushed us into a new realm of understanding this patient population. When a part of your brain is involved in generating a thought or performing an action, it burns energy in the form of glucose, and it's replenished through blood flow. As blood flows to that part of the brain, we're able to see that with the FMRI scanner.

I think one of the key insights was the realization that we could simply get somebody to lie in the scanner and imagine something and, based on the pattern of brain activity, we will be able to work out what it is they were thinking. We had to find something that produces really a quite distinct pattern of activity that was more or less the same for everybody. So, we came up with two tasks. One task, imagine playing tennis, produces activity in the premotor cortex in almost every healthy person we tried this in. A different task, thinking about moving from room to room in your house, produces an entirely different pattern of brain activity; particularly, it involves a part of the brain known as the parahippocampal gyrus. And again, it's very consistent across different people.

So, we realized that we could use this as a simple mechanism for asking yes or no questions. We could say, well, I'm going to ask you a question. If the answer is yes, imagine playing tennis. If the answer is no, imagine thinking about moving through the rooms of your home. I can still remember exactly what it felt like the first time we saw a patient that we thought was in a vegetative state activate their brain in the scanner. The patient's name was Kate. Nobody would have predicted that we would have seen brain activity in response to asking a patient to do something. And when we first saw it, it was absolutely astonishing.

Before we made that discovery, nobody ever bothered to look at any of these patients. Very few people even ask the question: Is it possible that some of them are there? Now, people ask this question all the time. We've scanned several hundred patients who were presumed to be in a vegetative state. It turns out that about 20%, or one in five of them, is not that at all. By that, I mean they're aware of the situation they're in, they're aware of conversations going on around them, they have thoughts, they have emotions. They maybe even have feelings about their future but are largely unable to move any part of their body.

I think you could very easily describe what we've done as an early version of mind reading. I think over the next few years this is going to be a really exciting area of research and we will move closer and closer to being able to decode what somebody is actually thinking. We are now in a position where we can ask some of these patients what it is that would make them more comfortable, even, are you in any pain? And of course, we can act on those questions, we can make them more comfortable.

Communication is the thing that really makes us human. If we can give these patients back the ability to make decisions, I think we can give them back a little piece of their humanity.