Sep 19 2008

Studying Near Death Experiences

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Comments: 16

Near death experiences (NDEs) have been a favorite topic for the paranormal crowd for some time. If one could prove that consciousness survives the physical death of the body that would go a long way to opening the door to a wide range of paranormal claims. NDEs often occur in the medical setting, and this is partly why a team of doctors from the UK and USA are planning a rigorous study of NDEs.

That NDEs occur is not controversial – many people report remembering experiences around the time of cardiac arrest from which they were revived. Typical experiences include a sense of floating outside of one’s body, even looking down upon oneself and the events going on. Some people report a bright light, and others report “passing over” and being greeted by deceased loved-ones. The experience is often peaceful or euphoric, which contrasts to the way people feel when they eventually wake up. Surviving a cardiac arrest takes its toll and is not a pleasant experience.

The question is not whether or not people have such experiences – the question is how to interpret them. Just as even the most rigorous skeptic does not question that people see UFOs, but rather what the UFOs likely are.

The burden of proof for anyone claiming that NDEs are evidence for the survival of the self beyond the physical function of the brain is to rule out other more prosaic explanations. This burden has not been met.

Neuroscientists are piecing together plausible explanations for each of the components of the NDE. The sensation of floating outside one’s body can be reliably induced by suppressing that part of the brain that makes us feel as if we possess our bodies. The experience is identical to that reported by those who have had an NDE. This experience can be replicated by drugs or magnetic stimulation. There are even reports (I have had one such patient) of people who have a typical NDE experience during seizures. The bright light can be explained as a function of hypoxia (relative lack of oxygen) either to the retina or the visual cortex. Any everything else is simply the culturally appropriate hallucinations of a hypoxic brain.

Critics of such explanation try to argue that during the experience the brain is not active, therefore the brain cannot be the source of the experiences. There are two problems with this argument. First, it has not been established that the brain is not sufficiently active to generate experiences. In all cases people survived the experience (by definition) to report what they remember. That means the brain did not go entirely without oxygen for very long or otherwise it would have been catastrophically damaged. During cardiopulmonary resuscitation (CPR) the cardiac output is about 20-25% normal – enough to delay damage to tissues. So the brain is getting some oxygen. Not enough to be conscious, but enough to have some function – perhaps generate a dream-like hallucination or out-of-body experience.

Second, the argument assumes without justification that the memories reported by those who survive CPR and have an NDE were formed during the CPR or when they were unconscious. It is more likely that some or all of those memories formed when the person was waking up adn their sense of time is as distorted as all their brain function. Unlike in the movies, people do not wake up fully conscious and lucid after having their heart restarted. After minutes of CPR the brain has taken a hit due to the hypoxia. People typically wake from this event slowly – taking hours or even days, depending on the duration and quality of the CPR. They will necessarily pass through a phase where they are what is called encephalopathic (their brain is functioning but not well), which is a type of delirium. It is common to have bizarre thoughts and perceptions, hallucination, and illusions during this period.

When patients then fully wake up to report their experiences, all they have is their memories, which includes the memories of the transition period from unconscious, through a delirious period, and to fully conscious.  They have no way of knowing when those memories formed.

The only way to definitively distinguish between memories formed during CPR and those formed during the period of encephalopathy is for the memories to contain specific details that could only have been obtained during the CPR. This claim is often made, but either there is a lack of compelling documentation, or the details are too vague to be definitive. People describing a typical CPR experience, for example, is not specific. Sometimes people after a NDE will claim to recognize the nurse or doctor who worked on them, but they may just be attaching those memories to people they encountered before or after the experience.

This brings us to the proposed study. What Dr. Sam Parnia, the head of the study, wants to do is to place a sign with specific information on it on top of shelving so that it can only be viewed from the ceiling. These will be placed in intensive care units and emergency departments. Patients who experience cardiac arrest and survive will be systematically interviewed at the participating hospitals and asked if they had any NDE and also be asked if they were able to identify the signs on top of the shelves. Assuming no cheating goes on, the only way such patients could have obtained the information would be if there experience of floating above their bodies was an actual experience interacting with the real physical world.

The study is likely to take 2-3 years so we won’t have results for a while.

The purpose of the study explicitly recognizes that the claim that NDEs are a non-physical experience of consciousness requires this type of evidence to distinguish it from a mere hallucination of a hypoxic or encephalopathic brain.  I predict that the study will be negative, and that proponents of NDEs as a spiritual experience will be unmoved by this evidence.


16 responses so far

16 Responses to “Studying Near Death Experiences”

  1. Steve Pageon 19 Sep 2008 at 10:16 am

    Nice job, Steve. I can’t help but feel that we’ll be hearing the patter of Egnorant feet over hear pretty sharpish, though.

  2. jonmckon 19 Sep 2008 at 10:18 am

    Richard Feynman describes an induced out-of-body experience he had in Surely You’re Joking. If I remember correctly, sensory deprivation–sound and sight specifically–brought it on. He talked about being able to see himself from the outside, how he tried to experiment with the phenomenon.

    I do wonder what the history of the “bright light phenomenon” is, though. My guess is that it’s a recent phenomenon that coincides with the advent of CPR and defibrillators, and the synthesis of drugs like epinephrine, atropine, etc. (all of which happened about the same time).

  3. Steven Novellaon 19 Sep 2008 at 10:22 am

    He is still behind on his Shiavo rant.

  4. Jim Shaveron 19 Sep 2008 at 3:45 pm

    Proposed message for one of the signs: “WE ARE SORRY FOR THE INCONVENIENCE.”

  5. pekka son 19 Sep 2008 at 4:15 pm

    Might the medical staff know the nature of the signs? Isn’t there a great risk of information leakage in that case? Is this controlled for in some way? Since extraordinary claims require extraordinary proof the controlls have to be extraordinarily tight. Am I wrong?

    And what kind of criteria are they using for evaluating patient feedback on the signs? How accurate must the descriptions be to be labeled hits? Will subjective validation be a problem? How well are the interviews documented? Are the interviewees aware of the nature of the signs?

    Are there other possible problems?

    I’d really hate if this kind of research were found to be useless because of sloppy methodology.

  6. sock puppeton 19 Sep 2008 at 11:45 pm

    As a doctor how do you handle this, I can only imagine you “roll” with there interpretations as there wouldn’t be, on an individual basis, be a point in offering alternative explanations.

    ps it’s greeted: “greated by deceased loved-ones”

  7. ccromeon 20 Sep 2008 at 1:40 pm

    I’ve had this kind of experience many times, induced intentionally. As a kid, I’d often faint when I stood up. The dreaming/floating and intense dreams are an absolutely incredible experience. Really cool. In high school, some friends and I would ‘pass each other out’ by hyperventilating, then holding our breath. I can’t imagine it was really good for us, but what can I say, we were idiots.

    I can attest, the hallucinations were quite amazing.

  8. Roy Nileson 20 Sep 2008 at 3:11 pm

    I’m told that whenever these experiences include brief glimpses of deceased relatives waiting on the “other side,” these people always have their clothes on. Apparently the soul of modesty is not just an idle metaphor.

  9. bundleson 21 Sep 2008 at 6:43 am

    sock puppet: it’s their (“roll” with there interp…), you used “be” twice in a row, and your whole sentence is a run-on. Let’s keep it about the issues and save correcting the good Doctor for spell-check.

  10. pholton 22 Sep 2008 at 5:06 am

    I’m a bit doubtful about this. Not because it’s not a good idea to study this phenomena but because Parnia seems like a true believer.

    If the results are negative I’d expect we will hear no more about it. It’s not the first time he’s undertaken this kind of study. See this story here:

  11. sock puppeton 23 Sep 2008 at 12:11 am

    I never claimed to be an English major, I certainly make my grammar mistakes and I would be lost without spell check. I only offered that in case Steve wanted to fix it, being that it is a blog and mine only a comment, You also notice I kept it about the “issues” and only put that as a post script. Though I appreciate your concern.

  12. daedalus2uon 24 Sep 2008 at 9:22 am

    ccrome, that is an exceedingly dangerous practice. What you are doing is inducing ischemic preconditioning in the brain. That shuts down necessary aspects of brain maintenance to conserve ATP for cells to remain viable but perhaps damaged. Damaged but alive is infinitely better than dead.

    There are several aspects to this damage, the long term wear and tear from reduced maintenance including unrepaired DNA damage, the acute loss of neurons due to active “pruning” to reduce metabolic load to match perfusion supply.

    The visual effects are likely very much like what sometimes occurs during migraine. Migraine is also a triggering of ischemic preconditioning and also causes long term brain damage and also causes visual effects.

  13. mnairon 24 Sep 2008 at 12:53 pm

    Sam Parnia’s claims of being a scientist with his “research”A Groundbreaking Study into the Nature of Life and Death does the same thing for Cornell University as John Mack did for Harvard with his alien abduction “research”.It is only in a country where (supposedly )half the people believe in angels that he can get this kind of coverage.Obviously if a person who is comatose/cardiac arrested /hypothermic gets revived the person was never dead.The term”near death” has no more scientific validity than “creation science”

  14. Frankiemouseon 04 Oct 2008 at 12:13 pm

    i know this comment is a bit late on this post and this is also total hearsay, but i trust the person from whom i heard it. the University of Pittsburgh Medical Center has already done this study a few years ago. i don’t know if it was an official study, or just an informal attempt to gather information. what they did was place signs on the walls above cabinets so they cold not be seen from anyone standing at floor level. i believe it was throughout one of their hospitals and not just in the er. no one who worked in the hospital (drs, nurses, etc) new what the signs said and they signs were periodically switched between the rooms. over the course of the study none of the people who reported a NDE even mentioned there being signs let alone accurately relaying what they said.

  15. cuervoon 17 Oct 2008 at 3:26 pm

    Sorry it’s late but :

  16. [...] Deepak Chopra, have tried to use near-death experiences as support for a mind separate from brain. I have written about his before as well. There are two reasons why NDEs are not evidence for a mind separate from brain. The first [...]

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