Friday, October 20, 2017

Consciousness after death

Death just became even more scary: scientists say people are aware they’re dead because their consciousness continues to work after the body has stopped showing signs of life.

That means that, theoretically, someone may even hear their own death being announced by medics.

The claim was made by Dr Sam Parnia, director of critical care and resuscitation research at NYU Langone School of Medicine in New York City.

He and his team are looking at people who suffered cardiac arrest, technically died, but were later revived. It’s the largest study of its type ever carried out.

Some of those studied say they had awareness of full conversations and seeing things that were going on around them, even after they were pronounced dead.

These accounts were then verified by the medical and nursing staff who were present at the time.

Death is defined as the point at which the heart no longer beats, and blood flow to the brain is cut
off. Dr Sam Parnia said: “Technically, that's how you get the time of death – it's all based on the moment when the heart stops.

“Once that happens, blood no longer circulates to the brain, which means brain function halts almost instantaneously.

“You lose all your brain stem reflexes – your gag reflex, your pupil reflex, all that is gone.”

However, there’s evidence to suggest that there’s a burst of brain energy as someone dies.

In 2013 researchers at the University of Michigan looked at the electrical signals inside the brains of nine anaesthetised rats having an induced heart attack.

They saw activity patterns which are linked to a “hyper-alerted state” in the brief period after clinical death.

Dr Parnia said: "In the same way that a group of researchers might be studying the qualitative nature of the human experience of 'love', for instance, we're trying to understand the exact features that people experience when they go through death, because we understand that this is going to reflect the universal experience we're all going to have when we die."


  1. Li D, Mabrouk OS, Liu T, Tian F, Xu G, Rengifo S, Choi SJ, Mathur A, Crooks CP, Kennedy RT, Wang MM, Ghanbari H, Borjigin J. Asphyxia-activated corticocardiac signaling accelerates onset of cardiac arrest. Proc Natl Acad Sci U S A. 2015 Apr 21;112(16):E2073-82.

    The mechanism by which the healthy heart and brain die rapidly in the absence of oxygen is not well understood. We performed continuous electrocardiography and electroencephalography in rats undergoing experimental asphyxia and analyzed cortical release of core neurotransmitters, changes in brain and heart electrical activity, and brain-heart connectivity. Asphyxia stimulates a robust and sustained increase of functional and effective cortical connectivity, an immediate increase in cortical release of a large set of neurotransmitters, and a delayed activation of corticocardiac functional and effective connectivity that persists until the onset of ventricular fibrillation. Blocking the brain's autonomic outflow significantly delayed terminal ventricular fibrillation and lengthened the duration of detectable cortical activities despite the continued absence of oxygen. These results demonstrate that asphyxia activates a brainstorm, which accelerates premature death of the heart and the brain.

  2. This borderland is becoming increasingly populated, as scientists explore how our existence is not a toggle—“on” for alive, “off” for dead—but a dimmer switch that can move through various shades between white and black. In the gray zone, death isn’t necessarily permanent, life can be hard to define, and some people cross over that great divide and return—sometimes describing in precise detail what they saw on the other side.

    Death is “a process, not a moment,” writes critical-care physician Sam Parnia in his book Erasing Death. It’s a whole-body stroke, in which the heart stops beating but the organs don’t die immediately. In fact, he writes, they might hang on intact for quite a while, which means that “for a significant period of time after death, death is in fact fully reversible.”…

    And in New York, Parnia spreads the gospel of sustained resuscitation. He says CPR works better than people realize and that under proper conditions—when the body temperature is lowered, chest compression is regulated for depth and tempo, and oxygen is reintroduced slowly to avoid injuring tissue—some patients can be brought back from the dead after hours without a heartbeat, often with no long-term consequences. Now he’s investigating one of the most mysterious aspects of crossing over: why so many people in cardiac arrest report out-of-body or near-death experiences, and what those sensations might reveal about the nature of this limbo zone and about death itself…(continued)

  3. (continued)But sometimes people who’ve been rescued, thanks to persistent, high-quality resuscitation, come back with stories that are quite clear—and eerily similar. These survivors can be thought of as having crossed over to the other side and returned with stories that offer some insight into how it feels to die. Their tales from the gray zone have been the subject of some scientific scrutiny, most recently in a study called AWARE (AWAreness during REsuscitation), led by Sam Parnia. Beginning in 2008, Parnia, director of resuscitation research at Stony Brook University, and his colleagues looked at 2,060 cases of cardiac arrest at 15 American, British, and Austrian hospitals. Among them were 330 survivors, 140 of whom were interviewed. Fifty-five of the 140 patients said that during the time when they were being resuscitated, they perceived some kind of awareness.

    Though most couldn’t quite recall details, others mentioned sensations similar to those found in best-selling books such as Heaven Is for Real: time either speeding up or slowing down (27 people), peacefulness (22), separating from their bodies (13), joy (9), or seeing a bright light or golden flash (7). Some (the exact number wasn’t specified) said they remembered bad sensations: fear, drowning or being dragged through deep water, or in one case, seeing “men in coffins being buried upright.” The study, Parnia and his co-authors wrote in the medical journal Resuscitation, provides “further understanding of the broad mental experience that likely accompanies death after circulatory standstill.” They wrote that the next step would be to study whether and how these episodes—which most investigators call near-death experiences (NDEs), though Parnia prefers “actual death experiences”—affect survivors after recovery, either with positive influences or negative ones, such as cognitive problems and post-traumatic stress. What the AWARE team didn’t explore was a common aftereffect of NDEs: a renewed sense of purpose and meaning to one’s life. That’s the feeling you often hear about from survivors—especially those who go on to write books about it. Mary Neal, an orthopedic surgeon from Wyoming, mentioned that effect to a large audience at a 2013 New York Academy of Sciences panel discussion called Rethinking Mortality. Neal, author of To Heaven and Back, described drowning while kayaking in Chile 14 years earlier. She said she could feel her spirit peeling away from her body and rising out of the river, as her knees bent backward, breaking her bones. She remembered walking down an “incredibly beautiful pathway toward this great domed structure that I knew was the point of no return—and I could hardly wait.” She described thinking how strange the whole experience was, wondering how long she’d been underwater (later she learned it had been at least 30 minutes), finding comfort in the knowledge that her husband and children would be fine without her. Then she felt her body come out of the boat and could see the first responders doing CPR. She heard one of them calling to her, “Come back, come back!”—which she said she found “really very irritating.”

    Kevin Nelson, a neurologist at the University of Kentucky, was on Neal’s panel, and he was skeptical—not of her memory, which he acknowledged was intense and valid, but of its explanation. “These are not return-from-death experiences,” he said, also contradicting Parnia’s view of what had happened. “During these experiences the brain is very much alive and very much active.” He said that what Neal went through could have been a phenomenon called REM intrusion, when the same brain activity that characterizes dreaming somehow gets turned on during other, nonsleep events, such as a sudden loss of oxygen. To him, near-death and out-of-body experiences are the result not of dying but of hypoxia—a loss of consciousness, not of life itself.

  4. To Sam Parnia, death is potentially reversible. Cells inside our bodies don’t usually die when we die, he says; some cells and organs can remain viable for hours, maybe even days. The timing of the declaration of death is sometimes a matter of personal attitude, he says. When he was in training, he notes, people would stop CPR after just five to ten minutes, assuming that any longer would mean irreparable brain damage.

    But resuscitation scientists have learned ways to keep the brain and other organs from dying even after the heart stops. They know that lowering body temperature helps—which happened naturally with Gardell Martin, and which happens deliberately in some ERs that routinely chill patients before doing CPR. They know that persistence helps too, especially in hospitals that use machines to regulate chest compressions or that someday might use drugs such as iodide.

    Parnia compares resuscitation science to aeronautics. It never seemed possible for people to fly, yet in 1903 the Wright brothers flew. How incredible, he says, that it took only 66 years from that first, 12-second flight to a moon landing. He thinks such advances can happen in resuscitation science too. When it comes to reversing death, Parnia believes we’re still in the Kitty Hawk era.