1 in 4 vegetative patients can still follow instructions

An international study has found that one in four patients in a vegetative or minimally conscious state are actually able to follow instructions and perform cognitive tasks. The research was carried out on a large cohort of patients, including a hundred in Cambridge. Emmanuel Stamatakis from the University of Cambridge is part of the study...

Emmanuel - We put these people in an MRI scanner or we fitted what we call an EEG cap, it looks like a hair net with sensors on it on their head. And we measured activity in their brain. Now the activity was in response to something we asked them to do. So we asked them to think they're playing tennis for about 30 seconds, and then we asked them to stop and then we asked them to play tennis again or move their hand. Imagine they're moving their hands. So 30 seconds on, 30 seconds off. We then do a mathematical analysis of this data and we see which part of the brain they use to think they're moving. And if they respond to this task, it means, first of all, they understand language, they understand the instruction, they can retain the instruction, they have what we call working memory, and they can do the task, they can imagine they're moving. So a very complex set of skills is required to carry out this task.

Chris - Quite a while ago, I remember a colleague of yours, Adrian Owen, came on this program and said, to actually some dramatic fanfare, that people who were regarded as completely cut off from the world could communicate in this way. They asked people to imagine giving someone a tour around their house versus, as you say, playing tennis. And they could see the different activations in their brain and they concluded these people were responding meaningfully and that perhaps people we'd regarded as unconscious, not as unconscious as we thought. So what's the question you've asked next then? How have you built on that study from nearly 20 years ago?

Emmanuel - So that original study was carried out in a handful of patients. Now we're having a group of 350 patients. The data from which was acquired from all over the world, mostly northeast US, Paris, Liege in Belgium, Cambridge. So this is the biggest group of patients we have ever looked at to understand whether there is residual cognitive function.

Chris - And what fraction of people who are in that state have this residual cognitive function, then, based on these big numbers you've now looked at.

Emmanuel - So, so far studies with a lot smaller numbers suggested 10% to 20% could respond to these tasks. For the first time with this group of 350 people, we found out that a quarter can respond to these tasks.

Chris - That's a big number. And it's alarming in a number of ways because what this means is that people who we had looked after but perhaps regarded as not really there with us, are probably listening to a lot of what's being said around them and they're thinking, and they would probably love to communicate, but they can't.

Emmanuel - Absolutely. This discovery, this research presents us with a huge number of ethical considerations. You mentioned one of them yourself. Should we have these discussions around these patients? Should we try to perhaps harness what we've discovered and work towards some means of communication?

Chris - Because you can use this almost like a yes no answer system, can't you? Nod for yes, shake your head for no. Because you can ask them questions, look at the brain response, and this means you can have a, albeit limited, but a conversation with these people for the first time.

Emmanuel - Absolutely. The task you mentioned earlier, if one imagines one is playing tennis, the area of the brain you use is quite high in the brain. If you imagine you wandering around the rooms of your house, the area of the brain that responds to this is quite low in the brain. So we have two distinct areas. So yes, in a way we can use that kind of task to respond yes or no. At the same time, with functional imaging, what we can do these days is we decode pictures we look at. So we can look at brainwaves and decide, well, a computer can decide what kind of picture you're looking at. So I don't think it's going to be very far before we can advance this to speech and language.

Chris - Have you had some meaningful conversations with people in this study? The participants as in, apart from just asking them yes or no type things, have you begun to elicit information from them that gives you some kind of insight into what it's like to be in their situation?

Emmanuel - No. At Cambridge, we haven't. I think we will need to, again, going back to the ethical implications of this request, ethical approval before we start doing something like this, but this kind of result may open the way to that kind of study.

Chris - Does it also open the door to better rehabilitation? Because when someone hurts their leg, we give them physiotherapy, we exercise the damaged leg and we restore movement and so on. If someone is regarded as in a persistent vegetative state, there's nothing happening neurologically, we thought, therefore we didn't exercise the brain. Have we missed an opportunity to rehabilitate them? Could we now reopen that door and restore better function for those people?

Emmanuel - There are two directions that research is going on that particular front. We have published work two years ago using, again, functional MRI, suggesting that dopaminergic drugs may be a way forward with this kind of patient.

Chris - These are the same drugs that we give to people with Parkinson's disease. They mimic the action of dopamine.

Emmanuel - Absolutely. At the same time, there's a huge revolution in a way happening with what we call neurostimulation, stimulating the brain with ultrasound or with magnetic waves, non-invasive techniques and invasive techniques where neurosurgeons implant electrodes and we started understanding better what unconsciousness means. So I think the future is bright for this kind of patient.

Chris - You've dwelled on the ethics a couple of times. One of the things that's immediately coming to the front of my mind is that we sometimes, unfortunately in medicine, find ourselves in a situation where we have to make a decision about whether to carry on treating someone. And very often people look at a person who's in a position like this and they say, well, we don't think there's any prospect of recovery. And that influences the decision. Is that going to change then off the back of what you've found?

Emmanuel - I think it should change. I think we have established that we have technology that at least in cases where patients are responsive, can give us additional information than what we have currently, than what medics who take those decisions consider. I think again, in the very near future, we should see changes in this kind of consideration.