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Student , Cooper Union for the Advancement of Science and Art

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How does life/death manifest itself in the human brain? Is brain death the ultimate end stage of life?

Recently, I watched the TED talk “Stroke of Insight” by Jill Bolte Taylor (http://www.ted.com/talks/jill_bolte_taylor_s_powerful_stroke_of_insight.html), in which she discusses the experience of having a stroke from a scientific perspective. She was able to diagnose herself throughout the process, even as her brain functions slowed or stopped altogether. Her story gives rise to a very important question: what is the connection between life, death, and the human brain?

In my Bioelectricity class this week, we discussed the use of EEG’s to record brain waves. A patient whose EEG reading shows a lack of brain activity is declared to be “brain dead.” In the medical community, “brain death” is considered to be equivalent to “death.” However, many consider this definition of death to be problematic. Even when a patient exhibits a lack of brain activity, her or she may still have functioning organs. The circulatory and respiratory systems, for instance, have been observed to be active in people who are brain dead. Is it really appropriate to define death as the cessation of brain function? Or, should the medical definition of death be modified from its current form?

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  • Mar 8 2012: I think that we should keep the term "brain dead"to mean just what you described, and that is different from being completely dead.
    • Mar 8 2012: Vlad,
      Thank you for your contribution!
      I think the issue here is that we don't have a clear definition of what "completely dead" means. The convention in the medical sphere, for instance, is to consider a person completely dead once brain function ceases.
      • Mar 8 2012: It doesn't seem like it should be so hard... death is cesation of neural activity without chance of recovery.

        Braindead is cessation of major brain function with significantly diminished (i.e. not in a coma, or unconcious) chance of recovery.

        The difference between significantly diminished and without chance is whether or not the brain has the capacity to regenerate the neural matter that is damaged or loss.

        I suppose with our imperfect understanding and tools, this ambiguity could be cause for concern for some. But really, the intention is to define between; obviously this person is stuffed (i.e. catastrophic brain matter destruction, but somehow miraculously the body/organs can still operate with sufficient intervention), and we are uncertain of the state of this person's neurlogical function (i.e. there's no higher level brain function, but the brain doesn't appear to be destroyed).

        Nonetheless, as a pragmatic person that values life, I recognize that holding PVS patients with extremely low recovery chances at the expense of accomodating for other patients with a better chance of survival and recovery is generally counterproductive. Ideally, we would release PVS patients as the facilities and accomodations are required; placing PVS patients at lowest care priority.
        • Mar 8 2012: George, it seems that you have accepted the medical definition of death as the cessation of neural activity. Certainly, once you accept this definition, the matter of life vs. death becomes significantly less complicated. What I propose in my question is that we (as a society) should decide whether the medical definition of death itself should be amended. In many cases, the heart continues pumping, the body continues to regulate its temperature, etc. after the brain "dies." Can we really consider a person who has living organs, tissues, and cells dead? Or, should a person be considered dead only after all of his or her cells are dead?
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          Mar 13 2012: Personally, I believe that with the current system and the technology we have available to perform the diagnoses of “brain death” (along with any errors it might have), the decision and ultimately the very definition of death lies solely on the patient’s family. Until there is solid evidence that a drug or a certain stimulation might reactivate (and in which cases it does not) a brain dead patient, the ball remains firmly with each patient’s medical proxy. In the current system, we cannot even think of imposing a limit on when to call a “brain dead” person dead. The hospital would get sued for all it’s worth. Some families, who believe that “brain death” is equal to death, could certainly argue that the hospital was trying to exhort extra money by keeping the patient in the hospital. Others might accuse the hospital for killing a live person solely for organ transplants and cite the very cases cited above of miraculous recoveries.
      • Mar 9 2012: As humans, we take our identity from our capacity for higher order thought. Even in diminished forms, as long as there's still some inkling that remains, then we include them in the category of human and assign them all their appropriate rights.

        Given that... if a person irrevocably loses their capacity for higher order thinking... that is, they become a person whose brain may or may not be alive enough to maintain basic bodily function, but nothing else, then it would seem as though they cease to be human in a manner that is critical to them. The critical factors of the mind/body that make up that self identity has perished.

        In that case, then for all intents and purposes should be considered dead - not assigned more rights than a body that has functioning organs that never had a functioning mind (which is only a possibility as a hypothesis, but is appropriate for this thought experiment).

        From a personal point of view, I think the discontinuity of brain wide electrical activity means that we're already expired from a personal point of view. I base this on the idea that if we were to clone myself through the process of violently ripping apart my molecular structure to read it - wait a moment or many... then reproduce us molecularly identically - that my consciousness would not magically transfer to that individual, as otherwise identical as he would be to me.

        Accepting that PVS is just a step above death is a pragmatic concension on my behalf, recognizing that most people do have a natural (if erroneous) attachment to the flesh/body of a person.
        • Mar 14 2012: I agree with your assertion that the individual is characterized by the consciousness and without the possibility of continuity of consciousness, the individual should be considered dead. But the issue of PVS is a complex one, not to mention a political hot potato. Like you, I think that there is value in keeping these patients alive so long as there is even a remote possibility of future recovery. It is important to recognize, though, that there are possible pitfalls in the diagnostic process and that current technologies and methods are limited. Call me an idealist, but today's major brain trauma might be tomorrow's migraine headache.

          And of course, whenever you talk about taking someone off life support who is arguably still "alive" by some definitions, you will encounter the slippery slope argument, which, despite all denials of constructivist lines in the sand, is as valid here as anywhere else.

          No one likes to talk about triage and rationing of care, but, as you aptly point out, in the real world these scenarios occur with enough frequency to warrant the appropriate planning. I think each patient must be evaluated on a case-by-case basis and care must only be terminated if the condition is hopeless under current methods and practices, resources are absolutely necessary for other patients and with the weighty consideration that the patient might be cured or proved curable the next day by some new medical innovation.
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      Mar 8 2012: Right on on Vlad
      Brain dead plus the body stopping functioning would be the definition of medically dead, artificially alive would be on respirators.You could be brain dead and artificially alive, or artificially alive and not brain dead. We need multiple categories of life and death, and they should expand to include the various levels of consciousness as well. Biologically active but not viable, would be the condition of early stage fetus's , artificially viable for many premature births , then the many stages of consciousness, sleep ,waking, comatose, dreaming,hallucinating, this would include the many near death experiences and the unusual circumstances that allow revival of some children immersed in cold water for extreme periods which occur, then there would be brain dead or not brain dead , and artificially alive or biologically alive. Artificially supported would be people with pacemakers artificial hearts or in need of dialysis, or defibrillators. The needs of people in various conditions must be planned for and that means having an accurate census of them, which requires accurate categories.

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