Detecting Awareness in the vegetative and minimally conscious states: novel clinical applications

In recent years, improvements in hospital care have lead to an increase in the number of people surviving severe brain injury. Although some people make a good recovery, many do not, and they progress to a vegetative or a minimally conscious state. These are very complex conditions that are difficult to assess at the bedside because these patients are often unable to move or speak. It is therefore difficult to determine how much they understand and what abilities they retain. For the last 10 years, we have been exploring whether state-of-the-art brain imaging technology (fMRI) can provide a solution to this problem, with some notable successes. For example, in 2006 we showed that a patient who had all the behavioural signs of being in a vegetative state was in fact consciously aware and able to generate responses with her brain activity. We now wish to extend this research to assess a range of brain functions, including memory and language, in a much larger group of patients and to follow them up over time to see whether the additional information that brain imaging provides can tell us who is most likely to recover, and why. We will also develop new techniques that can be used at the bedside, for patients who cannot be put into MRI scanners or for situations where fMRI is not available. In some case, these systems may allow patients who are unable to communicate effectively using speech or movement to convey their thoughts and emotions using so-called ?brain-computer interfaces?. We will distribute the results of this research as widely as possible, in order to encourage the use of brain imaging technology in assessing the effects of serious brain injury. In doing so, we believe that it will have important implications for diagnosis, the development of potential therapies and quality of life in this patient group.

In recent years, improvements in intensive care have lead to an increase in the number of patients who survive severe brain injury. Although some of these patients go on to make a good recovery, many do not, and some of these individuals progress to a vegetative or minimally conscious state. It is extremely difficult to assess cognitive function in these patients, because their movements may be minimal or inconsistent, or because no cognitive output (e.g. speech) is possible. In recent years, we have demonstrated that functional neuroimaging may provide a solution to this problem; we have used fMRI to show that aspects of speech perception, emotional processing, language comprehension and even conscious awareness may be retained in some patients who behaviourally meet all of the criteria defining the vegetative state. To fully realise the translational potential of this work we now need to apply these techniques to a much larger group of patients and to follow them longitudinally to determine whether our imaging data has prognostic value. In doing so, we will broaden our fMRI paradigms to examine other cognitive domains that may be intact in patients who are unable to move or speak. We will develop complementary electrophysiological methods to ensure that the maximum number of patients can benefit, if necessary through assessments at the bedside. We will also extend our pilot work with brain-computer interfaces to develop methods of real-time communication for some of these patients. This research will have profound and direct implications for the assessment, diagnosis and clinical care of patients after brain injury. The work will inform medical ethics and legal discussions (in terms of withdrawal of life-sustaining therapies) and drive future efforts to develop interventions to facilitate recovery and quality of life. Finally, such efforts are likely to provide important new prognostic indicators and improve therapeutic choices by revealing the pathophysiological mechanisms responsible for different outcomes in this patient group.