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Sunday, February 7th 2010

When You’re Not A Vegetable

A joint British and Belgian group has published new findings with fMRI evaluating consciousness in patient’s previously meeting clinical classification for persistent wakeful unconscious states.

We used functional magnetic resonance imaging (MRI) to assess each patient’s ability to generate willful, neuroanatomically specific, blood-oxygenation-level–dependent responses during two established mental-imagery tasks. A technique was then developed to determine whether such tasks could be used to communicate yes-or-no answers to simple questions.

Of the 54 patients enrolled in the study, 5 were able to willfully modulate their brain activity. In three of these patients, additional bedside testing revealed some sign of awareness, but in the other two patients, no voluntary behavior could be detected by means of clinical assessment. One patient was able to use our technique to answer yes or no to questions during functional MRI; however, it remained impossible to establish any form of communication at the bedside.

The emphasis is my own because it is those findings which made the news as the NEJM published the study ahead of print online. While hyperbolic, the results have elicited titles in the media such as ‘I’m alive! ‘Vegetative’ patient speaks to scientists using his brainwaves‘ and responses from pro-life advocates such as ‘‘Stop dehydration deaths,’ says Terri Schiavo’s brother in response to new brain scan‘.

Functional MRI has been front and center in the news the past several years with claims of scans that can predict people’s responses and actions before they make them and decipher people’s motives or tell us when they’re lying or telling the truth.

And it’s true studies such as those by Monti, et al raise important and serious questions about the right to life and the right to die. In an editorial to accompany NEJM’s publication Dr. Allan Ropper says,

Even in a preselected population, brain activation was infrequent, but it occurred often enough that it will now be difficult for physicians to tell families confidently that their unresponsive loved ones are not “in there somewhere.”

Indeed, the MRC and Belgian group’s efforts are game changers certainly. It, and future studies along the same lines, have made and will make the main stream news and will no doubt be commonly quoteb by anyone faced with a loved one who is awake but seemingly not there by any measure short of fMRI. And they should be. For all the reassurance the medical community gives family and friends the misdiagnosis of persistent vegetative states is a problem. Now further uncertainty is thrown on it.

But as much as the preservation of life and function is an important goal, arguably secondary only to primum non nocere, I still think caution is in order when using information as Monti et al have provided. Dr. Ropper likely says it better than I can,

First, in this study, brain activation was detected in very few patients. Second, activation was found only in some patients with traumatic brain injury, not in patients with global ischemia and anoxia. Third, cortical activation does not provide evidence of an internal “stream of thought” (William James’s term), memory, self-awareness, reflection, synthesis of experience, symbolic representations, or — just as important — anxiety, despair, or awareness of one’s predicament. Without judging the quality of any person’s inner life, we cannot be certain whether we are interacting with a sentient, much less a competent, person. Moreover, persons who look to this study to justify continued and unqualified life support in all unresponsive patients are missing the focus of the findings.

The presence of some rudimentary preserved cognition that is indicated by means of functional MRI will no longer be in question, but its meaning will continue to be subject to interpretation.

Be gentle in how we use these new resources to define consciousness; how we use these new resources to define who is still is with us.

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