Sunday, September 10, 2006

Detecting awareness in a gravely brain injured woman

Science has published research findings suggesting awareness in a woman in a persistent vegetative state (these findings were published as 'Brevia,' essentially an announcement of findings, not as a full peer-reviewed research article). The 23 year old woman, in a PVS due to a traumatic brain injury, was studied 5 months after her injury using functional MRI. Essentially the fMRI findings suggested that the woman's brain was responding 'appropriately' (as in how an uninjured brain would respond) to verbal cues and commands--some part of her brain heard the commands and processed them appropriately. The story has been making the rounds on the news, and while I haven't checked out the so-called pro-life blogosphere I imagine the findings are being used to all sorts of ill-ends including and not limited to revisiting the death of Terri Schiavo. I found this NY Times article quite reasonable, and it also made the revealing point that this woman 11 months post-injury recovered a little and is now in a minimally conscious state.

Some things to keep in mind about this event. 1) What has happened, while probably rare, is also perfectly consistent with the known natural history of the PVS. PVS following traumatic brain injury (as opposed to anoxic brain injury) has a better prognosis: people make some sort of recovery more often than in anoxic PVS and it takes longer before one's PVS is considered permanent (meaning <<1% chance of recovery). Even anoxic PVS's of 5 months duration have been known to have some recovery. It seems that the researchers caught fMRI evidence of some form of consciousness before it was clinically evident: there should be nothing surprising about this. 2) Could fMRI be used as a way of predicting those likely to make some recovery? Sure, of course, but no one has any clue if this will pan out or not yet. 3) These findings represent a growing refinement in medicine's understanding of prolonged states of impaired consciousness and we should be prepared for more, much more, of this in the coming years. The PVS, the MCS, etc., are clinical, bedside diagnoses and describe a final common pathway from a multitude of neurologic insults but there are probably many subtypes of each with their own etiologies, natural histories, (and maybe at some point therapies), etc., and things are going to change. Helping families make decisions about appropriate medical care for loved ones in these conditions is already complicated, and will probably get more complicated at least for a while as new information comes out. 4) The fact remains that for many of us the distinction between the prolonged states of impaired consciousness is meaningless & when people say "I don't want to be kept alive artificially if I'm like that," by "like that" they mean profoundly disabled and unable to have meaningful communication with loved ones. This includes the PVS, the MCS, profound dementia, etc., and the prospect of going from a pain- & suffering-free PVS to a potentially suffering- & pain-full MCS doesn't seem like a good deal. Not everyone of course would agree with this, but I'd wager most people reading this blog and most North Americans would agree with this. (A distinction between the two which is more likely to have meaning to at least some people is the difference in their prognoses as one's chance of a decent neurologic/cognitive recovery in a PVS is tiny vs. not quite as tiny in an MCS.) 5) These are findings in a single person and no one knows how frequently, if ever, this will be replicated let alone what the long-term implications will be. 6) These findings have zero implications either medically/scientifically or morally/ethically for the highly controversial public PVS cases including Terri Schiavo.

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