Posted: Sep 13, 2012 11:07 am
DrParisetti wrote:3. Many posters take the position that the conscious experience owes to the fact that the brain is not "dead" and there is some residual activity. Professionals in this field, who do this for a living and are not related to NDE research, say that this is categorically impossible. There may be residual activity but not even the most basic, survival-related functions of the brain stem shut down. People don't even breath autonomously, but are supposed to have a structured conscious experience, generally described as "more real that everyday reality"? And produce long-term memory?
You are failing to understand the argument. Even if we assume there is a period where the brain is completely devoid of any activity whatsoever, we are talking about people who suffered a cardiac arrest, and then were resucitated. So this period of "brain death" was preceded and followed by periods during which at least rudimentary brain activity was present. So by far the more likely and parsimonious explanation is that the experiences under discussion are the result of those periods, when the brain is still active, but severely impaired.
4. Other arguments are recursive. How can you have consciousness when there is no brain? Well, that is my question!
And until you can provide an answer, the most likely explanation rermains that you can't have consciousness without a brain, and we have no evidence that you can.
5. Fantasy, fear of death, hallucination, CO2, hypoxia and drugs have been dealt with in the landmark 2001 Lancet paper by Pim Van Lommel et al.
http://profezie3m.altervista.org/archiv ... et_NDE.htm
That paper is not very convincing at all. As discussed by Dr. Mark Crislip:
I read the article from the perspective of a practicing physician who spends all his time in an acute care hospital and has been involved with many cardiac arrests over the years. The NDE question in this study hinges on whether the were dead or nearly dead. In the article the authors “defined clinical death as a period of unconsciousness caused by insufficient blood supply to the brain because of inadequate blood circulation, breathing, or both. If, in this situation, CPR is not started within 5–10 min, irreparable damage is done to the brain and the patient will die.”
Every patient in this study had CPR, most within 10 minutes of their cardiac arrest, so they all had blood delivered to their brain. That is the point of CPR. The authors write: “If purely physiological factors resulting from cerebral anoxia caused NDE, most of our patients should have had this experience.” Yet, good CPR does not lead to cerebral anoxia. Most patients in this study did not have an NDE because they had CPR, so they had blood and oxygen delivered to the brain; thus, they could not have an anoxia mediated NDE.
So the real question is whether patients who had brain anoxia had an NDE, and there is no way to determine that in this paper. CPR by its self is not a good surrogate for cerebral anoxia. Having a cardiac arrest and being promptly coded does not mean there is insufficient blood and oxygen being supplied to the brain. CPR has variable efficacy, depending on the both the patient and the experience of the provider. Most of us who have had to be involved with a code know, for example, the horrible sensation of all the ribs cracking when you start CPR on a frail old lady and knowing that the CPR is probably not going to be effective.
As a result of variable CPR, the time it takes the brain to become anoxic is variable. And it is surprising at how little oxygen people can tolerate with no discernible dysfunction in their cognition, although you might not want them flying your 747. People come into the hospital all the time with the amount of oxygen in their blood decreased by 30,40, and even 50 percent, and yet can still walk and talk.
6. We have indications that people are conscious at the moment when they are being resuscitated from a long series of well documented anecdotes. But we agreed that we will leave them aside. (Still, it would be interesting to understand why people would invent such elaborate stories, lie, and involve others in their well-orchestrated deception...).
Anecdotes are anecdotes, no matter how "well-documented". And no one here is accusing these people of inventing these stories.
Recollections of death: A medical investigation (New York: Harper and Row, 1982). Cardiologist Michael Sabom reports on his careful and systematic work. The first part of the research consisted of collecting data: Sabom used detailed protocols to interview patients who reported visual experiences while undergoing cardiac surgery or in connection with cardiac arrests. He then went on to consult with members of the medical teams and other witnesses, and also examined the clinical records of these patients, in order to determine to what extent these perceptions could be verified. In most instances, Sabom was able to provide compelling evidence that these patients were reporting precise details concerning their operation, the equipment used, or characteristics of the medical personnel involved, which they could not have known about by normal means.
The second part of Dr. Sabom’s investigation consisted of a control procedure, devised to further test the reality of what the patients reported. He identified 25 chronic coronary care patients who had never been resuscitated, and asked them to imagine what the procedure would be like as if they were a spectator of their own resuscitation, much like the NDEers experience. The results from this control group were intriguing, to say the least. 22 of his 25 control respondents gave descriptions of their hypothetical resuscitation that were riddled with errors; their accounts were often vague, diffuse, and general. According to Sabom, the reports from patients who had actually been resuscitated were never marred by such errors and were considerably more detailed as well.
Again, this assumes that the recollections occurred from a time where brain activity was completely absent. It's not surprising that people who had never been resuscitated would have less knowledge of the procedure than people who were.
Here's an interesting question: Are people who are under a general anaesthetic still aware of their surroundings? They just might be. So how can we assume that people who are seemingly unconscious from a cardiac arrest are not aware?
And, critics have to explain the continuity of experience described by NDEers
Easily done by someone who knows how human memory typically works.
DrParisetti wrote:Oh, one more thing, quickly. Explaining the dramatic, long-standing psychological changes with "a brush with death". Oh, please! You will have to do a LOT more than that. Come on! How do you explain that only NDErs show this changes, an all those who had the same condition but did not have an NDE don't? I am a passionate mountain climber and peel off a face at 3,000 metres in 2009, flew for some 20 metres and fortunately only broke an ankle. That was quite a brush with death, and have none of the changes described in the studies.
Again, easily explained: People who have had a NDE believe they have had an experience of an afterlife. So even if this experience is completely hallucinatory, it would still affect their lives as if it were real.
I'm a psychiatrist who specializes in schizophrenia. Many of my patients have their lives deeply alterred by their experiences of delusions and hallucinations. But that does not mean those experiences actually exist outside of their minds.