Vegetative patients could be contacted using simple, cheap and portable technique – EEG

By Dr. Ananya Mandal, MDNov 10 2011

Scientists from the UK and Belgium have found a way to communicate with brain damaged patients who appear to be in a vegetative state. Writing in The Lancet medical journal they describe how they measured electrical activity in the brain to detect consciousness. The technique, known as EEG or electroencephalogram, is painless and involves attaching electrodes to the head.

Doctors hope it can be used as a diagnostic tool in homes and hospitals. For the study they conducted a trial that involved 16 patients at Addenbrooke's Hospital in Cambridge and the University Hospital of Liege in Belgium. All had been diagnosed as being in a vegetative state. The patients were asked to imagine wiggling their toes or squeezing their right hand. The brain activity of three of the 16 patients showed they were repeatedly able to follow commands.

“The vegetative state is often referred to as a condition of wakefulness without awareness, and that's because these patients open their eyes, they often appear to look fleetingly around the room, but certainly there's never any signs they're actually aware,” said principal researcher Dr. Adrian Owen of the Centre for Brain and Mind at the University of Western Ontario. “They don't actually respond to anything in the outside world, so you can't attract their attention, you can't make them look in one direction or another,” Owen said Wednesday during a webcast to describe the research.

Professor Owen said, “Many areas of the brain that activate when you perform a movement also activate when you imagine doing it. We know these three patients were conscious as they were able to respond repeatedly to the instructions we had given them. One of the patients was able to do it more than 100 times.”

Professor Owen's team at the MRC Cognition and Brain Sciences Unit in Cambridge previously showed that it was possible to communicate with some vegetative patients using functional magnetic resonance imaging (fMRI). But many brain injured patients cannot be assessed in these scanners because they have metal plates or pins, or they are unable to remain still.

The EEG device on the other hand is comparatively cheap and portable. Professor Owen said, “This is exciting because it means we can get out into the community, take it to patients in nursing and care homes, and assess many more patients at the bedside to see if we can detect covert awareness.” The EEG had 129 electrodes and fits over the head a bit like an elasticated hair-net.

Helen Gill-Thwaites, a consultant in the diagnosis of low awareness states at the Royal Hospital for Neuro-disability (RHN) in Putney said, “For a small proportion of patients EEG could be a very useful tool in the diagnostic process. It would however be a useful addition and not a replacement, to current methods of assessing severely brain-injured patients. Sadly, in my work outside of the RHN I meet many patients who have never had a proper assessment and have been wrongly diagnosed as being in a vegetative state.”

Paul Matthews, Professor of Clinical Neurosciences, Department of Medicine, Imperial College, London said, “The approach suggests a simple, practical way in which some of these patients might be helped to communicate. This innovative work has taken fundamental brain science right to the bedside. Efforts to further evaluate this and related approach in the clinic should be prioritized.”

Julian Savulescu, director of the Oxford Centre for Neuroethics, said, “This important scientific study raises more ethical questions than it answers. People who are deeply unconscious don't suffer. But are these patients suffering? How bad is their life? Do they want to continue in that state? If they could express a desire, should it be respected? The important ethical question is not: are they conscious? It is: in what way are they conscious? Ethically, we need answers to that.”

“That's the challenge for the immediate future, to work out how we can speed this up,” Owen said. “And actually only then will somebody really be able to have a conversation in real time with one of these patients.” “It opens up a whole world of new opportunities for communicating with these patients and finding out what their inner world is like,” Owen said. “And I think it would be a mistake to jump in with both feet and say, 'Right, well, let's start asking them whether they want to live or die, or what they would like to happen to them.'…Just because somebody can answer a yes or no question doesn't mean that (we know) everything about their inner mental world — we don't know whether they're depressed, unhappy or happy, or whether they want to live or die.”