Those who are locked into paralyzed bodies, yet still aware, say later that it is like being buried alive. They have thoughts yet are completely incapable of relaying those thoughts to the outside world. So if we cannot communicate or receive a response from someone in a vegetative state how can we know for certain they are still aware? How can we know that they are conscious? Until recently there really has been no way of knowing for certain.
Scientists have been trying to crack this holy grail of Philosophy since medicine has been facing such consciousness disorders. Within the last five years Adrian Owen, who holds the Canada Excellence Research Chair in Cognitive Neuroscience and Imaging at the University of Western Ontario, and his teams have been fine tuning a technique using brain imaging where they have successfully communicated with vegetative patients, allowing them a voice to respond. Interestingly this "voice" comes from asking the patients to imagine playing tennis.
SmartPlanet spoke with Owen about this unusual discovery and the potential groundbreaking innovations coming within the next 10 years.
SmartPlanet: What is your definition of consciousness?
Adrian Owen: I think about it simply in terms of wakefulness and awareness. These are two different components that you can actually measure. If we think about what happens to you when you have a general anesthetic, there are two ways you start to lose consciousness: One is that you start to fall asleep and you lose wakefulness, and the other is you stop being aware.
SP: What is the difference between being awake and being aware?
AO: Well the difference becomes most apparent in patients in a vegetative state. Those are patients that are awake but they are unaware. They’ll open their eyes, they’ll even appear to look around the room although they won’t look at anything in particular, but they are entirely unaware. You cannot attract their attention, they don’t turn to a noise in the room. In a sense the lights are on but there is nothing going on inside.
SP: How can you tell if someone is aware?
AO: This is the interesting thing about consciousness, how can you really tell if somebody is conscious? Thinking about the two components, with wakefulness it’s very easy, you can just look at somebody and if their eyes are open then you know that they are awake. With awareness it’s much more difficult. You actually can’t tell that somebody is aware. We don’t have any instrumentation or special scans that you can just put on their head and know that they are aware. Essentially you have to ask them something that will generate a response.
SP: And how do we do that?
AO: The example I use is of a doctor by the side of a road accident who asks the patient to squeeze their hand. If the patient squeezes their hand you know that they are aware. Because you know they can hear and understand what you say, and generate a response. But if the patient doesn’t squeeze your hand, you have two possibilities: One is that they are not aware, and the other is that they just can’t respond. So awareness is very, very tricky.
In fact I’ve always argued it’s impossible to conclude that somebody is not aware. It’s not philosophically possible. But you can use other methods to conclude that somebody is aware.
SP: What have you been doing to try and detect awareness in patients in vegetative states?
AO: We’ve been following patients now for many years. Patients who have a variety of conditions known as disorders of consciousness. The vegetative state is the big daddy of those disorders. Another one is the minimally conscious state, which is similar to the vegetative state but there is some evidence that they are aware.
And we’ve come to realize something that is really fundamental about this population of patients. And that is: What you see is not what you get. Just testing them, doing a neurological examination, looking at their behavior, that often doesn’t tell you the whole story about the patient. We found this when we started using new types of brain imaging. And in the early days we’d find some activity going on that we really couldn’t explain.
Around 2006, we had this idea that perhaps some of these patients are in fact conscious and aware but are completely locked into their bodies. Completely incapable of generating responses so when you ask them to do something they won’t do it but in fact the will may still be there.
So we worked out a way with a technique called functional magnetic resonance imaging (fMRI) of getting people to make responses simply by using their brains. The analogy is to think about the doctor by the side of the road asking the patient to squeeze their hand. Instead of doing that we asked the patient to activate a certain area of their brain, and we know that when you ask people to imagine certain things they will activate particular areas of the brain.
SP: You asked patients to imagine playing tennis, right?
AO: Right. If I ask you to imagine playing tennis, you will activate a part of your brain known as the pre-motor cortex. That is the part of the brain responsible for sending the signal to prepare to move. It’s not the part that actually does the movement. If you simply imagine waving your arms as most of us do when we imagine playing tennis this area of the brain lights up. And what we found is that when we put healthy people into the scanner and we said imagine playing tennis, this part of the brain would light up. And then we’d say, now stop. And that part of the brain would stop lighting up.
And we found it was just as consistent as asking someone to squeeze your hand. It’s just a different way of getting a response out of somebody, but it doesn’t require them to have any physical ability to actually respond.
SP: And then you tried it on a patient.
AO: Yes. In 2006 we put our first vegetative patient into the scanner. She was a woman who had been involved in a road traffic accident and had been vegetative for five months. When we asked her to imagine playing tennis the pre-motor cortex suddenly lit up and when we said “stop” the pre-motor cortex would stop lighting up.
And she could do this again and again.
SP: There is not something specific to the sport of tennis that allows this technique to work, correct?
AO: Right. I still use tennis but I have tried several other things like swimming or soccer. But it turns out that tennis is particularly good, because all we really want people to do is to imagine moving their arms around. If people run around it gets a bit confusing. It activates too many different parts of the brain.
I could put you in our scanner and I could ask you to imagine playing tennis and I could say that this very specific part of your brain will light up. Five years after our first trial with this it still takes my breath away. We have a running gag in my lab where whenever this happens one of us will turn to the other and say, "You know this fMRI stuff really works." When are actually able to point at a bit of the brain and say: When I tell this person to do this thing that part is going to light up. It’s tremendously powerful. Because when it happens you know it’s meaningful, it doesn’t happen by chance. It is not automatic.
SP: What sorts of techniques are refining now?
AO: Well electroencephalography or EEG is one of them. There are a lot of really smart people working on brain-computer interfaces with EEG who I think can use what we’ve done and do some pretty cool things. I don’t think it’s going to be very long before we see a patient, who is entirely non-responsive, actually communicating via some form of brain-computer interface using EEG-based technology.
SP: Hopefully with new merging of techniques we can have more complicated communication beyond a yes/no format which is what you can get now with the “imagine playing tennis” task.
AO: Absolutely. We are actually achieving quite a lot with yes/no. But yes/no is an answer to a question. Ideally you would like a patient to spontaneously generate a question or a speech or a desire. I think that is what EEG will provide because it’s portable. We do great things with fMRI and it still sets the gold standard, but fMRI scanners are not going to get any smaller [they require a huge room] and they are not going to get less expensive. So there is not going to be a world where we send a patient home with their personal MRI scanner. But I can imagine a world where we send a patient home with an EEG kit. That is entirely plausible and affordable.
SP: Have any of your patients recovered?
AO: The better your MRI response the more likely there will be some recovery. We’ve seen a significant correlation over the last 10 years. And that could be important in life or death decision making. If someone is generating good activity then maybe you might think longer about what that means for that person’s future.
On the other hand: When we talk about “recovery” we are not talking about the same type of recovery people might think of. I have seen a few hundred patients over the last decade, several have recovered, but none of them have gone back to work, can live alone, are self-sufficient. They are still severely disabled. If you have been in a vegetative state for a few months, you are never going to recover in the sense that most think of when we say “recovery.”
SP: So when trying to communicate with a vegetative patient, will these techniques become a routine part of the examination?
AO: Well I am a big believer in this now, so yes I believe it will be routine. And I can see the good it can do. I think it’s pretty inevitable that the various medical bodies that would have to come together in different jurisdictions. I am sure they are going to include brain imaging in the next version of the criteria for analyzing and recognizing such patients. In the UK it’s the Royal College of Physicians. In that sense I believe it will become very widely used to determine whether or not any of these patients are in fact conscious.
SP: If you were to dream big what would you want fMRI or brain scanning to be able to do?
AO: I think a truly portable and affordable system for allowing a patient who is unresponsive to communicate on a routine basis with their family members. If we manage that I really think we’ll have achieved something great. It’s a big aim, in the sense that so many things have to come together.
For me and my work I am really interested and have this goal of working with people who have absolutely no way of communicating. I think about how awful it must be to be conscious and feel like you could respond but not have anything come out. You are literally trapped inside your body. Those are the people I want to help. If we can get somebody who is in that kind of situation to actually be able to communicate on a routine basis then we would have done something quite amazing.
SP: What do you think will come in the next few years?
AO: We are exploring various spelling devices using both EEG and fMRI. Also we are exploring whether, instead of imagining playing tennis, could they imagine a word they want to convey, and could we decode that word and work out what they are thinking. Right now this is not technically possible. But there are people working on those sorts of ideas. Of decoding brain activity, in ways that will allow us enable people to convey more information.