The researchers said that while it is still early days, they hope their method will lead to ways of enabling aware patients trapped in unresponsive bodies to control their environment, express their feelings, and communicate more fully.
You can read about the study in a paper published online on 3 February in the New England Journal of Medicine, NEJM. The research was based at two major referral centres in Cambridge, UK and Liège in Belgium, and the researchers were from the Medical Research Council (MRC), the Wolfson Brain Imaging Centre in Cambridge and the University of Liège.
In their background information, first author Dr Martin Monti, a Postdoctoral Researcher at the Medical Research Council, Cognition and Brain Sciences Unit in Cambridge, UK, and colleagues wrote that doctors have great difficulty diagnosing disorders of consciousness and the rate of misdiagnosis is about 40 per cent, hence the urgent need for new reliable methods to complement bedside testing, especially in the case of patients where there are hardly any behavioural signs they are aware.
For the study, they used functional magnetic resonance imaging (fMRI) to scan the brains of 54 patients for specific activation of blood-oxygenation- level-dependent responses to being asked to perform well-known mental imagery tasks.
The fMRI technique they used in this study was a further development of one they first used with a patient in a vegetative state in a study they published three years ago.
The results showed that:
- 5 of the patients were able wilfully to modulate their brain activity.
- 3 of the 5 patients revealed signs of awareness when they underwent further bedside tests.
- The remaining 2 patients, however, showed no voluntary behaviour that could be detected clinically.
- One of the 3 responsive patients was able to use the technique to answer "yes" or "no" to questions during the fMRI, however "it remained impossible to establish any form of communication at the bedside", wrote the authors.
"A small proportion of patients in a vegetative or minimally conscious state have brain activation reflecting some awareness and cognition."
"Careful clinical examination will result in reclassification of the state of consciousness in some of these patients," they added, and suggested the "technique may be useful in establishing basic communication with patients who appear to be unresponsive".
The male patient at the centre of this study was in a road traffic accident in 2003 when he was 29 years old. He sustained a severe traumatic brain injury that left him physically unresponsive and doctors concluded he was in a vegetative state.
Using their latest fMRI method, Monti and colleagues mapped the patient's brain while they asked him to answer "yes" or "no" to questions like "Is your father's name Thomas?" The scan showed that the patient could wilfully change his brain activity to communicate his answers.
One of the methods they used in the study was to ask the patient to imagine doing something like "playing tennis" when the correct answer was spoken. The fMRI showed that patient's brain became active in the pre-motor cortex, the part that deals with movement.
Co-author Dr Adrian Owen, also from the MRC Cognition and Brain Sciences Unit, told the press that:
"We were astonished when we saw the results of the patient's scan and that he was able to correctly answer the questions that were asked by simply changing his thoughts."
"Not only did these scans tell us that the patient was not in a vegetative state, but more importantly, for the first time in 5 years it provided the patient with a way of communicating his thoughts to the outside world," he added.
Co-author Dr Steven Laureys, a member of the team based at the University of Liège in Belgium said that so far the scans have been the only viable way to communicate with the patient since his accident.
"It's early days, but in the future we hope to develop this technique to allow some patients to express their feelings and thoughts, control their environment and increase their quality of life," said Laureys.
Monti explained that scanning brain activity of patients who are aware but can't move in the way they did in this study, could be used to address important clinical problems, for instance doctors could ask if they are feeling pain, so they can decide which painkillers to give them.
"Willful Modulation of Brain Activity in Disorders of Consciousness."
Monti, Martin M., Vanhaudenhuyse, Audrey, Coleman, Martin R., Boly, Melanie, Pickard, John D., Tshibanda, Luaba, Owen, Adrian M., Laureys, Steven.
N Engl J Med Published online 3 February 2010.
Belgian Man Trapped In Coma For 23 Years Was Conscious Throughout, 24 November 2009
Source: MRC CBU