I actually think about "brain death" a lot. It seems to me that people think of brain death as a yes/no switch. When really it's likely a continuum (please tell me if your studies say the opposite, I am interested).

I struggle to figure out what I would write on my advanced directive. It seems impossible. If I were comfortable, if I could feel the sun on my skin, hear sounds, if my mind had some thoughts or something like thoughts, then (putting aside the cost to society (a big putting aside)) I'd like to live on. People talk about people in a "vegetative state," like a vegetable, or a potted plant. What if that were an interesting or pleasant state?

Yes, I know, weird and inefficient, my thoughts. In opposition: the costs of keeping someone alive past their "productive" time, the emotional costs to family members, the medical complications that may accompany the loss of brain and motor functioning (I'm not a medical person but I imagine infections, bed sores, collapsed veins, all sorts of yuck).

Yeah, that's pretty much what I'm finding. What I find most interesting, and scary, is that people are saying that the medical tests we use to determine brain functioning are likely not actually measuring viability; there's obviously an implicit assumption, when we test for "critical brain functions," that we know (a) which functions of the brain are indeed critical, and (b) how to accurately test for them.

What popped into my mind on reading that was a short article I saw recently about "junk DNA," and how researchers had totally written off large portions of genes as "not doing anything," but now they're finding that there are (of course) reasons for those structures to be there. I think we're so quick to assume that if we have basic understanding then that's the whole picture (especially if shiny new tests or technologies tell us so), and so we just assume that anything that doesn't fit into the shiny new framework must not be important or critical and can be written off.

Which I think was Agatha Christie's point with most of her mysteries -- you can't ignore the clues that don't fit your theory; if they exist, it means your theory's wrong, not that the clues are unimportant.

Therefore, in conclusion: We should, um, resurrect Agatha Christie and have her rule on this issue.

Or something.

My favorite quote from an article I read, which gets at your last point, Claudia: "Defining death is a different job from deciding when it is best to remove the life-support systems." Which I think turns it back into an issue with practical, implementable solutions, even if it's still obviously in fuzzy, difficult territory.

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I wonder what comas are like. My father spent 28 days in a coma. Then my mother had a talk with him and said it was OK to let go, she'd take care of us kids. He stopped breathing and his heart stopped five minutes later. and I'll never get over it though I was there soon afterward kissing his cold forehead

Relevant story in today's NYT Magazine (re brain-injured vet). I also remember the New Yorker article, maybe 1 year ago? About how some purportedly vegetative patients respond to words and sounds.

Here's the article from The New Yorker.

dabitch, very telling your comment on your father 'letting go'. Very. At least you were there for him...in the end. I think it mattered a lot that you came by to say 'Ciao'. I hope you don't blame your mother for telling him 'it's cool if you don't want to stay, but everything's under control'. After all, that shows true love, in my mind. You let people be free and themselves. That means to the end, as much as it hurts.
Sadly, I never knew my father much, but he died at a pretty young age [56]. I get the feeling, he let go long time ago, frankly, and after his 3rd heart attack that he made a conscious decision that that was it. The will is an important, ah, what's the word¿...component of life¿

I don't believe instruments can measure one's state of cognition or not.
There's something more going on than what any damn human 'instrument' can measure.

I am judging from the 'communication' that I have with my 106 year old grandmother. We've always been close. She can't talk. She's forgotten or rather, can't remember how to speak. But with touch, I hold her hand and speak to her, she does get it, not that she can respond verbally though. Touch focuses her attention on a different level, past verbal communication. Nor does it matter her hearing aid isn't up to scratch to her liking. But I know she's getting everything I'm telling her. I feel her frustration in trying to communicate verbally with me and understand completely what she's 'saying'. Yet, we can still communicate and 'talk'.
It's not an assumption on my part.
It's something that can't be explained in scientific terms, but something felt and understood on a completely different day to day level.

She's having her 106th birthday bash this week and judging from her reaction during her 105th bash, it'll be the same. She gets it, it's an occasion that's special and it seems everyone is there and wishing her well. So what, she can't speak to them, she still can communicate, if you take the time. She'll smile and laugh otherwise.
We give her some wine, food and cake and liqueur and she's just loving it, even though she gets a lot of attention at the home, daily, she knows this is a different day, even if it takes her some time to remember.. who are you¿ So I stay by her side, hold her hand and reintroduce her to whom this is...
It seems quite different from any kind of 'dementia' or Alzheimer's, which I'm familiar with, an ex g'f's father who didn't recognize his 3 daughters nor wife in the latter stage.

There was a scientist interviewed on CBC that had studied rats and concluded that rats taught a certain lesson was learned for rats all over. Say Australia. Just because the rats in Canada had learned a lesson, it was transmitted as knowledge learned in rats far away. I can't recall the term, however, interesting. Now, how are you going to measure that¿ You can't, it's in the ether, shall we say.
There is no ether measurement, see¿