Despite rigorous clinical assessment, a significant proportion of vegetative state patients are misdiagnosed. Recent studies have proven that a significant minority of these patients are consciously aware and, in some cases, their awareness of the outside world can be detected by functional magnetic resonance imaging (fMRI). While this solution is revolutionary in terms of patient care and facilitation, expense and accessibility prevent the wider use of assessing the majority of vegetative patients in this way.
The new research shows that 19% of a group of patients who were entirely unresponsive and presumed to be vegetative were actually aware – a figure that exceeds previous estimates of the number of people with undetected awareness in the group.
Dr Damian Cruse, the lead author of the study at the University of Western Ontario in Canada, says:
“Our new method uses electroencephalography (EEG) which is relatively cheap, portable and widely available. This means that we can now go out into the community and visit patients in their residential care homes or hospitals and provide a more accurate diagnosis than was previously possible.”
Dr Adrian Owen, a Canada Excellence Research Chair (CERC) in Cognitive Neuroscience and Imaging at Western’s Centre for Brain and Mind (CBM), adds:
“It’s astonishing. In some of these cases, patients who seemed to be entirely unresponsive to the outside world were able to signal that they were, in fact, conscious by changing their patterns of brain activity – sometimes hundreds of times.”
Professor Susan Gathercole, Director of the MRC Cognition and Brain Sciences Unit in Cambridge, adds
“An accurate diagnosis is vital to enable doctors to provide the best treatment and care options available. We are very pleased that the Medical Research Council has been involved in this fascinating study, which brings us one step closer towards improving diagnostic tools for patients thought to be in a vegetative state and pinpointing levels of awareness that were not previously possible.”
The researchers collaborated with colleagues from the MRC Cognition and Brain Sciences Unit in Cambridge, the Department of Clinical Neurosciences, University of Cambridge, and the Coma Science Group, University Hospital of Liège on this study.
Their findings are published online today in The Lancet.