Is the brain half full – or half empty?

There have been dramatic headlines in the media ('Coma Man. I think…I’m alive') following the publication yesterday of a new study using brain scans to detect consciousness in profoundly brain damaged patients. For the first time scientists and doctors have demonstrated that some patients diagnosed with persistent vegetative state may be able to communicate using functional magnetic resonance imaging (fMRI).

The technique itself has been described previously (including on this blog). Patients are asked to imagine themselves either playing tennis or walking around their house. The brain states associated with these different imagined activities are sufficiently different that they can be reliably distinguished using fMRI. The scientists, based in Cambridge and Brussels, have previously demonstrated that some patients in a vegetative state, appeared able to perform this task in response to instructions. The dramatic new finding is of a single patient in whom they used this paradigm to seek a response to questions (if ‘yes’ imagine playing “tennis”, if ‘no’ imagine walking around your house). This finding suggests that the patient in question – rather than being completely unaware, as would previously have been assumed of a patient in this condition, was in fact conscious. His state resembles that of a patient in a locked-in-syndrome, unable to move, but conscious and aware of his surroundings.

We have discussed elsewhere some of the moral, practical and legal implications of developments such as these for patients in a vegetative state. Further posts on this blog may discuss in more details the specifics of the new study and its limitations. But broadly there are two ways of looking at these findings.

The optimistic version, reflected in many of the media reports, is that this finding gives new hope to vegetative patients and their families. It can no longer be said, to borrow a phrase from James Rachels, that their ‘biographical life’ has ended. Patients who appear to all intents and purposes oblivious to their surroundings may nevertheless appreciate the presence of family and friends, hear their voices, and know that they are cared for. It raises the possibility of communicating with them, of assessing whether they are in pain  and treating it appropriately, as well as giving them a say in important decisions about their lives. By identifying patients with preserved capacity for consciousness it may enable targeting of treatments that would ultimately lead them to more significant recovery.

However, there is also a darker, more pessimistic reading of these results. So far, these findings have been found only in a small proportion of patients in a vegetative state. (The ability to communicate using brain scans has only been shown in a single patient). It remains conceivable, indeed likely, that the majority of patients in vegetative state are not conscious. Moreover, at this stage the technology is a long way from being able to provide reliable ongoing communication tools for patients. At best, patients, such as the one described in the report may be able to answer simple yes/no questions during the brief periods when they are inside an fMRI machine. The answers provided in such a setting may not be sufficient to allow patients significant input into decisions about life-saving treatment. Furthermore, there is a sense in which patients found to have preserved consciousness despite appearing to be in a vegetative state may be worse off. If they are conscious they are likely to be able to experience pain, discomfort and distress. It is perhaps little consolation to family members to learn that their loved one are in fact trapped inside their damaged brain, unable to communicate, to move, or to improve. At this stage there is no evidence that patients in vegetative state, found to have evidence of consciousness on brain scans are able to recover beyond an extremely impaired state.

It is likely that this new study will significantly impact on families, doctors, and courts – particularly in relation to decisions about life-sustaining treatment. It will raise uncertainty about whether or not a particular patient is conscious, even if they appear not to be. Some will almost certainly take these results to preclude withdrawal of life-saving treatment. However, there are both positives and negatives in the discovery of consciousness in a small number of patients diagnosed with vegetative state. Both the glass half-full and the glass half-empty interpretations have some merit. Brain scans, in and of themselves, do not answer the difficult ethical question about life-saving treatment.

LInks

Monti et al Willful Modulation of Brain Activity in Disorders of Consciousness NEJM 03/02/2010

Wilkinson et al. Functional neuroimaging and withdrawal of life-sustaining treatment from vegetative patients. Journal of medical ethics (2009) vol. 35 (8) pp. 508-11

Kahane et al. Brain damage and the moral significance of consciousness. The Journal of medicine and philosophy (2009) vol. 34 (1) pp. 6-26

Skene et al. Neuroimaging and the withdrawal of life-sustaining treatment from patients in vegetative state. Medical law review (2009) vol. 17 (2) pp. 245-261

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