The Border of Death

A human skull

This article is dedicated to the memory of Victor Mikecz (6-20-1926 – 4-13-2018), who passed away during the writing of this article.

Death seems like a black and white subject. There is not much middle ground between alive and dead. Or is there? The law has strictly defined definitions of death that are used during examinations and in making medical decisions for those kept alive by external life support. However, the border between life and death has many shades of gray. For those in states of persistent unconsciousness, life becomes a condition ranging from hope for full recovery to death only being a matter of time. For healthy individuals going through cardiac arrest, they may have “near-death experiences” with previously unexplained “lights.” New research in these subjects is giving humanity greater insight into both conditions of unconsciousness and the electrical nature of near death experience. Though death is defined legally, our understanding of human conditions near the border of death continues to grow with advances in brain research and electrical technology.

Background, The UDDA Death Document

In the United States, death is defined by the Uniform Determination of Death Act. The National Conference of Commissioners on Uniform State Laws wrote the document in 1980 for adoption across all 50 states, and is currently adopted by 37 US states, Washington D.C., and the U.S. Virgin Islands. The American Medical Association (AMA), the American Bar Association (ABA), and President’s Commission on Medical Ethics all approved this document. The document was necessary because medical methods throughout the 1970s were clashing with out-of-date legal standards of death. Simply put, at that time death was still defined by common law as the cessation of the cardiorespiratory system. The UDDA builds on the old common law by extending the definition of death to include complete not only heart and lung failure, but termination of all brain function, including the brain stem.

This is an important point, because the brain stem is a very tough little bugger,

The brain stem of a human brain
The three parts of the human brain stem.

and will continue to function under harsh circumstances. It is the most primitive part of the human brain. It handles some very core aspects of human functioning. Among other things, the brain stem controls the cardiovascular system, respiratory function, alertness, and consciousness. Therefore, loss of brain stem function is the end of the road for a human being. This total loss of function in the brain is a brain death.

Hello…? Any controversy in there?

Where exactly is the issue? The difference between between brain death and persistent vegetative states is critical in understanding how the US defines death and how patients are treated in each condition. Think of the term “brain-dead,” and the type of person it is used to describe—someone in a coma, someone unresponsive. This layman’s word is similar to brain-death but does not mean the same thing. Well, what many think is a brain death could be a persistent vegetative state (PVS). In a persistent vegetative state, medical care usually consists of nothing more than a feeding tube. People who have suffered severe brain trauma typically are the ones who suffer with persistent vegetative states. The condition is one in which the patient retains some function of consciousness. They exhibit sleep-wake cycles, and often can use some motor function such as use of their eye-lids. What is the difference, exactly between PVS, a brain death and a coma? The key difference is that people in PVS still retain function of their brain stem, whereas in a brain death, the brain stem has lost all function and the patient has to be supported by external equipment. Lastly, in a coma, the patient has lost all consciousness, and will not respond at all to touch, speech, or any other form of contact.

The Electric Brain

Advances in medical instrumentation now help determine the cognitive functioning of patients in PVS states. For example, in a recent article published in New England Journal of Medicine, researchers used fMRI to ask questions to a patient, and then measure the response using fMRI equipment. The article called Willful Modulation of Brain Activity in Disorders also states that

“…a small proportion of patients in a vegetative or minimally
conscious state have brain activation reflecting some awareness and cognition.”
-Martin Monti et. al,, New England Journal of Medicine
fMRI of brain
fMRI (functional Magnetic Resonance Imaging) allows doctors to view brain activity in real time.

The article states that scientists could ask questions and patients responded “yes” or “no” via measurement with fMRI. These researchers also state that new methods are required to make diagnoses of conditions of consciousness such as comas and persistent vegetative states. The article states that 40% of these conditions are misdiagnosed!

fMRI of yes/no answer
Actual “yes” and “no” responses of patients correspond with similar brain activity of control patients. Source: New England Journal of Medicine

Despite these scans appearing promising for all PVS patients, it is important to note that only a minority of PVS patients in this study exhibited this ability to “communicate” via fMRI in this study. Specifically, five of fifty-four patients (~9%) could do so. This is important to note, as fMRI is by no means a miraculous means of communicating, but can be effective for investigating the state of a patient’s conscious state.

On that same token, vegetative states encompass a wide range of conditions. The definition of the state is rather broad in most contexts. The Royal College of Physicians defines vegetative states as “A state of wakefulness without awareness in which there is preserved capacity for spontaneous or stimulus-induced arousal, evidenced by sleep–wake cycles and a range of reflexive and spontaneous behaviours.” In plain English, aside from sleep-wake cycles and some motor movement, vegetative states can be applied to a very broad range of states of consciousness after a traumatic brain injury. This is probably why fMRI communication does not work with all patients, some simply have more damage than others and are in lowered states of consciousness.

Life After Death for a Healthy Brain

Aside from other states of consciousness that linger near death, healthy human brains actually exhibit strange electrical activity after death. In a article published in PNAS called “Surge of neurophysiological coherence and connectivity in the dying brain,” researchers at the University of Michigan state that their research partially explains why many cardiac-arrest patients have “near-death experiences.” Their research shows that when rats clinically die, and blood flow stops to the brain, the brain actually exhibits electrical activity similar to that in conscious perception.

Jimo Borjigin
Jimo Borjigin
“High-frequency neurophysiological activity in
the near-death state exceeded levels found during the conscious
waking state. These data demonstrate that the mammalian brain
can, albeit paradoxically, generate neural correlates of heightened
conscious processing at near-death.”

Jimo Borjigin, et al., University of Michigan

The quote above paints a picture different from what researchers expected. After a clinical death, they expected brain activity to slow down to a halt. However, what they saw was quite different. Researchers found that the brain activity actually increased for a period after the death, resulting in a heightened state of consciousness processing. The brain scientists state that this electrical activity could account for the “lights” that people experience during near-death experiences of cardiac arrest patients.

Looking Deeper

The human brain is a miraculous work. Lingering states before death can be confusing for all involved, and education is critical to making decisions regarding loved ones. Currently, the US law has very specific rules for handling patients in comatose, PVS, and brain-death conditions. Current law also accounts for legal statements made before the patient fell into their condition.

Advances in fMRI technology are allowing doctors to make more accurate decisions in diagnosis. Physicians achieve this by comparing fMRI imagery of patients with severe brain trauma with control patients. Are some PVS patients capable of even more communication beyond yes or no questions? Will the use of this technology change our medical procedures and law? It is hard to say, but the future looks promising for using more advanced communications methods with brain damaged patients on the border of death.

Our understanding of near-death experience continues to give credence to reports of cardiac arrest patients. How will this body of research continue to grow? If electrical activity in the brain really is responsible for the “lights” experienced in death, can we officially include this experience in medical texts? Readers are encouraged to continue to push the boundaries of our current understanding of death. Doing so will not only increase our understanding of the ultimate commonality among creatures, but can bring feelings of peace when we or a loved one has to face it.

Legal Docs

UDDA Document

Scientific Articles

Monti, Martin, et al. “Willful Modulation of Brain Activity in Disorders of Consciousness | NEJM.” New England Journal of Medicine, www.nejm.org/doi/full/10.1056/NEJMoa0905370.

Borjigin, Jimo, et al. “Surge of Neurophysiological Coherence and Connectivity in the Dying Brain.” PNAS, National Academy of Sciences, 27 Aug. 2013, www.pnas.org/content/110/35/14432.abstract.

Photos

Top Skull Photo – Title: Memento Mori!, Author: Milan Nykodym, from Kutna Hora, Czech Republic,

fMRI (first)- John Graner, Neuroimaging Department, National Intrepid Center of Excellence, Walter Reed National Military Medical Center, 8901 Wisconsin Avenue, Bethesda, MD 20889, USA

fMRI (second) – Photo sourced from “Willful Modulation…” by Monti, Martin et. al.

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