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UK: "Caution urged over fMRI for life or death decisions"

"Bioethicists funded by the Wellcome Trust have urged caution over the use of advanced neuroimaging techniques in making life or death decisions about patients in a vegetative state. Writing in the 'Journal of Medical Ethics', researchers from the Oxford Uehiro Centre for Practical Ethics at the University of Oxford and colleagues say that while functional magnetic resonance imaging (fMRI) offers new insights into the conscious state of vegetative state patients, we still do not know how to interpret these findings.

'It is very tempting to think that brain scans will provide clear cut, black and white answers, but it is unlikely that they will,' says Dr Dominic Wilkinson of the Oxford Uehiro Centre, one of the authors of the paper.

'Even if they do, there are lots of difficult ethical questions that go with these decisions. Neuroimaging will not provide a shortcut or make these easier.'

After a severe brain injury, some patients emerge from a coma in a vegetative state where they appear awake but are unaware of themselves or their environment.

Previous studies have used fMRI to examine vegetative state patients for evidence of cognitive function. One study found two patients that could apparently obey commands to imagine different activities (in this case playing tennis and walking around a house) that activate different parts of the brain. The researchers claimed at the time that this provided definitive proof that the patients were conscious.

Findings like this have led to calls for fMRI to be used as evidence when making life or death decisions involving patients in a vegetative state.

However, after reviewing the scientific evidence, the authors concluded that the evidence for consciousness from fMRI is still unclear.

'The problem is with interpretation,' says Dr Wilkinson, 'whether these patients really are conscious or if it is just a reflex.' Patients under anaesthesia, for example, can show signs of cognitive brain activity, including language processing, even when unconscious.

'There is brain activity, but is that the same as consciousness? And even if it is, this pattern of brain activity is unlikely to be found in most patients in a vegetative state. Moreover, it is not clear whether such findings make the patients any more likely to recover from their severely impaired state.'

Nevertheless, Dr Wilkinson says it is increasingly likely that fMRI data will be called on, particularly in contentious court decisions over the withdrawal of life support.

'People place a great deal on the diagnosis of consciousness in a vegetative state. But hard evidence for this is hard to come by.'

'It is not clear that the science is ready to be used in the courtroom. We should be very cautious to avoid overcalling the findings of these studies.'

'The ethics and the science are some way from a complete approach,' says Professor Julian Savulescu from the Oxford Uehiro Centre and lead author on the paper.

'What is critical is deciding what matters - for example, whether a person should autonomously decide to live or die, or which lives are worth living. This is an ethical question that science cannot answer.'"


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