A recent study of brain scans in 125 people from multiple locations in the U.S. and Europe suggests a set of patterns of brain activity that are closely linked to differentiating human consciousness from unconsciousness, which has been an elusive Holy Grail for neuroscientists. [1] While the patterns are not yet “sufficient proof” of consciousness, this finding gives us one more tool in the difficult public policy issue of determining the point of “legal death.” Today’s cheery topic is the tie between loss of brain activity and the usually-undiscussed probabilistic math relating to death, plus the relationship of that math to ethical behavior and future public policy.

Remembering Terri Schiavo

I was doing graduate study in ethics in the early 1990s when the Terri Schiavo case, about a young woman who had suffered severe brain damage and lived in a form of “unresponsive wakefulness syndrome” (still more commonly called “persistent vegetative state,” an awful term) first hit the courts and the medical ethics classroom as part of a big malpractice suit,. This was over a decade before she became a cause célèbre in the popular press and Congress. The definition of consciousness itself became a key issue in the case. Was Mrs. Schiavo conscious in some form?

Despite massive, irreversible damage to her cerebral cortex, Schiavo continued to exhibit some eye movement and facial grimacing, which certainly gave an appearance of “something there.” Yet even in that early first court case, scientific evidence had been presented that these reactions were likely driven by basic brain stem activity without requiring any “higher-order” brain function, which she did not appear to have. In more common parlance, Mrs. Schiavo was “brain dead” in the early 1990s, but her other bodily functions were kept going through life support technology for over ten more years until several more rounds of court cases ended with these efforts stopped in 2005.

That first early-1990s court case brought to my attention a bit of this history of public policy’s determination of the point of “legal death,” as well as the mathematics of probability that have increasingly come to the fore. The legal and common definitions of death have evolved over the centuries.

Our “holy breath” 

Some of the first “science” learned and shared among early human populations was the observation that life had something to do with breath. Up through Greek and early Roman times, the concepts and words for “breath” and “spirit” were closely linked, if not identical. Such modern terms as pneumonia and respiration had their roots in ancient Greek and Latin, respectively, rooted in terms for breath/spirit.

If you had “good breath,” in other words warm unlabored breathing, then you had some “spirit of life” within you. When that breath turned “bad,” and then stopped completely, you were pronounced dead. Through the 1700s people would commonly put a mirror under a dying person’s nose to assess a point of “legal death” under the conventions of that age. In ancient Greek “science” terms, a living person’s breath had three essential elements: “air”, “fire” (warmth) and “water” (which condensed on the mirror, or not).

Heart death and brain death

Knowledge of the human circulatory system increased in the early 1600s, much of this demonstrated by English physician William Harvey (1578–1657). The concept of heart death, the cessation of the heartbeat and the pulse, eventually took on an equal or even greater role to the cessation of breathing in determining the point of death.

Brain death, the cessation of detectable neurological activity in the large cerebrum of the brain, was of course not measurable for another 300 years. Interestingly, it was the increasing feasibility of transplanting organs from one person to another, plus the growing ability to artificially sustain cardiac activity for long periods, that necessitated changes to laws worldwide in the 1960s, defining “brain death” as the final legal standard. However, as demonstrated by the Schiavo case, even that standard has proven to be scientifically problematic and culturally misunderstood.

The probabilities of death

Likely far more often than most people realize, people who die in hospitals live in a human-invented, machine-sustained “limbo” for either a short period or a long period until a consensus of family and medical staff determine certain of these efforts will stop, letting “nature take its course.”

Although hard numbers are rarely used (but more research could likely provide), there are two types of probability evaluations going on by medical personnel. The first is the probability of the person stabilizing at some more sustainable level of life. While people sometimes hang in this “limbo” state unchanged for some time, most of the time “things get worse,” which you can think of as us sliding down a probability curve, either slowly or quickly, where the “probability of coming back” becomes smaller and smaller.

The second probability estimate is “How far back toward normal will the person get?” This is the one neither well-understood by family nor well-articulated by physicians. In 2011, physician Ken Murray received a lot of attention for an essay, along with its statistical follow-up, which suggested that physicians have a darker view of the “quality of life” experienced by people “saved” by cardiopulmonary resuscitation (CPR) and similar technological advances, and more often than the general public personally choose not to use them.

The public policy question

I wrote an earlier post about “the mind-body dilemma,” that still separates the consensus of most neuroscientists from widespread public perception about what happens when our brains stop functioning normally. Where does the “mind” (often equated with the “soul” by religious people) go to? When should we “pull the plug?”

There is no avoiding the medical, ethical, cultural, and religious issues that come into play here, to which I add the public policy issues, as the question of “Who pays?” increasingly noses its way into the discussion. [2] Medical professionals are often uncomfortable with the “God language” that is the primary communication mode for many religious people. Most families of patients don’t know the “medical language,” and few people on either side know “ethical language” or the math of probability.

Out of that conflict of competing “languages,” a consensus public policy can arrive proactively or reactively. My observation of the current state of American medicine is that we are defaulting to insurance companies as “death/life” power brokers, which is probably the worst outcome or all.

Notes:

1. Sanders, Laura. “Brain Scans Uncover a Key Sign of Consciousness.” Science News, 8 Feb. 2019.
2. An excellent readable discussion of these issues from a medical perspective is found on the National Institutes of Health website: Manalo, Maria Fidelis C. “End-of-Life Decisions about Withholding or Withdrawing Therapy: Medical, Ethical, and Religio-Cultural Considerations.” Palliative Care, 10 Mar. 2013.