By using more portable and affordable means, Damian Cruse, a postdoctoral fellow at Western’s Brain and Mind Institute, plans to bring his research to the bedside. And for those locked in a vegetative state, it could mean an opportunity to once again communicate with family and friends.
Through the use of an electroencephalography (EEG) machine, portable enough to fit inside a pair of small suitcases, Cruse says testing can be taken directly to a patient’s bedside which “brings the real possibility that every patient may now be given the opportunity to demonstrate they are aware.”
As lead author for the study of this novel technique, published this week in The Lancet, the world’s leading general medical journal, Cruse says these latest findings have strong implications for family and friends of these patients. It is now considerably easier for them to learn what level of awareness their loved ones might possess.
OWEN
“I think you’ll appreciate that discovering that your friend or relative is able to understand you when you speak to them, and is conscious of what happens around them, is going to have quite a profound impact on both the patient and the family,” Cruse says.
In 2006, Western neuroscientist Adrian Owen, a colleague of Cruse, demonstrated for the first time some patients in a vegetative state not only may have cognitive thoughts, but also the ability to communicate.
While Owen’s work was revolutionary in terms of patient care, that didn’t mean access and affordability were in line. Up until now, assessments of vegetative patients have used functional magnetic resonance imaging (fMRI) which, while a fantastic technique, has a limited availability and high pricetag in Canada.
“It’s also the stress and expense involved in transferring a patient to an appropriate facility,” Cruse says. “The vast majority of these patients don’t reside near a scanner and, as a result of their injuries, it is often completely unfeasible to transport them to a facility where a scanner is housed.”
He adds a large proportion of patients also have metal implants as a result of their injuries, and would be unable to enter in the scanner regardless.
While an fMRI measures the flow of blood around the brain, an EEG measures electrical signals that come from the neurons in the brain, which can be used to determine which parts of the brain are responsive at particular points in time.
In most EEG set-ups, there is an amplifier or recording unit to which the EEG electrodes are connected, and a laptop to record the brain activity.
For this recent study, Cruse collaborated with colleagues from the Medical Research Council Cognition and Brain Sciences Unit in Cambridge, the Department of Clinical Neurosciences, University of Cambridge and the Coma Science Group, University Hospital of Liège.
They wanted to know if this cheaper method of diagnosis still returned useful and accurate assessments on the state of such patients. If so, the findings would open up access to more and more individuals.
In his previous work, Owen found 17 per cent of the two dozen vegetative patients studied retained a level of awareness, which could not be detected by observing their behavior. Cruse says similar results were found using the EEG technique.
“This EEG task, which we developed, had a group of 16 vegetative patients and we found that 19 per cent of these patients retained this covert level of awareness. Clearly, the proportions are very comparable between the two techniques,” Cruse says.
“It doesn’t means that all vegetative patients are aware; it is only some,” Owen adds. “But when you think of the number of patients there are around the world in this situation, 17-20 per cent is quite a lot of patients.
“Five years ago, I think it was inconceivable to most of us that we would ever be able to establish that a patient that appeared to be vegetative would actually be conscious. That generated yet another question and that was, ‘Could we make a portable version of this that we can take out and use in the community?’ That’s where we are at now.”
As for further research, this portable and inexpensive technique brings in the real possibility of practical communication with these patients, Cruse says.
“If they are able to understand what we say to them,” he says, “we can develop ways for them to answer us back using their thoughts.”
Damian Cruse, the lead writer on a study published today in The Lancet, demonstrates on post doc fellow (psychology) Irene Sperandio a new method using electroencephalography (EEG) to diagnosis individuals possibly diagnosed incorrectly as vegetative state patients.
