Hey THT: doctors study of the Near Death Experience...
Extract from an article in the current (June 2002) issue of The Fortean Times:
[quote]
How The Dead Live
The most comprehensive study yet of clinically dead people and their near death experiences, published in The Lancet, has raised some intriguing questions, reports Mark Pilkington
Might some remnant of consciousness survive when brain function has ceased? This is the question asked in a remarkable paper presented by four Dutch doctors in the 15 December edition of the venerable medical journal The Lancet. In 'Near-death experience in survivors of cardiac arrest: a prospective study in the The Netherlands', cardiologist Pim van Lommel and three colleagues describe an eight-year study of 344 heart attack patients, all registered as clinically dead with no brain EEG output before successful resuscitation.
Unlike most Near-Death Experience (NDE) studies, in which self-selected experiencers describe NDEs long after they actually took place, the subjects were interviewed as soon as possible after waking and questioned again two and eight years later. 62 of the patients, 18 per cent of the total, reported NDEs, 41 of them (12 per cent) described 'core' experiences featuring classic elements (of the typical NDE) such as the tunnel of light, life review, dead friends (appearing) and out-of-body experiences (OBEs).
Among the conditions suggested by sceptics to explain NDEs are the effects of anaesthetic or sedative medicines, religious beliefs or other psychological factors and most often, cerebral anoxia, the starvation of oxygen to the brain. However, the Dutch team found that neither medical nor psychological factors could adequately account for the experiences: "although all patients had been clinically dead, most did not [report] NDEs...If purely physiological factors, resulting from cerebral anoxia caused NDEs, most of our patients should have [reported] this experience. Patients' medication was also unrelated to the frequency of NDE. Psychological factors are unlikely to be important as fear was not associated with NDE."
One patient in the study afterwards identified a nurse who had treated him while he lay in a deep coma and then told her where she had placed his dentures. He also told her that "he desperately and unsuccessfully tried to make it clear to us [the doctors] that he was still alive and that we should continue CPR". The nurse stated that his condition was so poor they feared he would not survive.
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[quote]
How The Dead Live
The most comprehensive study yet of clinically dead people and their near death experiences, published in The Lancet, has raised some intriguing questions, reports Mark Pilkington
Might some remnant of consciousness survive when brain function has ceased? This is the question asked in a remarkable paper presented by four Dutch doctors in the 15 December edition of the venerable medical journal The Lancet. In 'Near-death experience in survivors of cardiac arrest: a prospective study in the The Netherlands', cardiologist Pim van Lommel and three colleagues describe an eight-year study of 344 heart attack patients, all registered as clinically dead with no brain EEG output before successful resuscitation.
Unlike most Near-Death Experience (NDE) studies, in which self-selected experiencers describe NDEs long after they actually took place, the subjects were interviewed as soon as possible after waking and questioned again two and eight years later. 62 of the patients, 18 per cent of the total, reported NDEs, 41 of them (12 per cent) described 'core' experiences featuring classic elements (of the typical NDE) such as the tunnel of light, life review, dead friends (appearing) and out-of-body experiences (OBEs).
Among the conditions suggested by sceptics to explain NDEs are the effects of anaesthetic or sedative medicines, religious beliefs or other psychological factors and most often, cerebral anoxia, the starvation of oxygen to the brain. However, the Dutch team found that neither medical nor psychological factors could adequately account for the experiences: "although all patients had been clinically dead, most did not [report] NDEs...If purely physiological factors, resulting from cerebral anoxia caused NDEs, most of our patients should have [reported] this experience. Patients' medication was also unrelated to the frequency of NDE. Psychological factors are unlikely to be important as fear was not associated with NDE."
One patient in the study afterwards identified a nurse who had treated him while he lay in a deep coma and then told her where she had placed his dentures. He also told her that "he desperately and unsuccessfully tried to make it clear to us [the doctors] that he was still alive and that we should continue CPR". The nurse stated that his condition was so poor they feared he would not survive.
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Comments
I'd be curious to see how they explain how schizophenia works, as well as the similarities of people using ketamine to that of a near death experience.
<strong>So, what is the Dutch team saying is happening?
I'd be curious to see how they explain how schizophenia works, as well as the similarities of people using ketamine to that of a near death experience.</strong><hr></blockquote>
I don't know if they cover those particular subjects, but you can read the full article (too long and complex to post here) on the <a href="http://www.thelancet.com"; target="_blank">Lancet web site</a>
BTW, this thread is not just for THT's benefit - other comments welcome
[quote] Discussion
Our results show that medical factors cannot account for occurrence of NDE; although all patients had been clinically dead, most did not have NDE. Furthermore, seriousness of the crisis was not related to occurrence or depth of the experience. If purely physiological factors resulting from cerebral anoxia caused NDE, most of our patients should have had this experience. Patients' medication was also unrelated to frequency of NDE. Psychological factors are unlikely to be important as fear was not associated with NDE.
The 18% frequency of NDE that we noted is lower than reported in retrospective studies,1,8 which could be because our prospective study design prevented self-selection of patients. Our frequency of NDE is low despite our wide definition of the experience. Only 12% of patients had a core NDE, and this figure might be an overestimate. When we analysed our results, we noted that one hospital that participated in the study for nearly 4 years, and from which 137 patients were included, reported a significantly (p=0·01) lower percentage of NDE (8%), and significantly (p=0·05) fewer deep experiences. Therefore, possibly some selection of patients occurred in the other hospitals, which sometimes only took part for a few months. In a prospective study17 with the same design as ours, 6% of 63 survivors of cardiac arrest reported a core experience, and another 5% had memories with features of an NDE (low score in our study); thus, with our wide definition of the experience, 11% of these patients reported an NDE. Therefore, true frequency of the experience is likely to be about 10%, or 5% if based on number of resuscitations rather than number of resuscitated patients. Patients who survive several CPRs in hospital have a significantly higher chance of NDE (table 3).
We noted that the frequency of NDE was higher in people younger than 60 years than in older people. In other studies, mean age at NDE is lower than our estimate (62·2 years) and the frequency of the experience is higher. Morse10 saw 85% NDE in children, Ring1 noted 48% NDE in people with a mean age of 37 years, and Sabom8 saw 43% NDE in people with a mean age of 49 years; thus, age and the frequency of the experience seem to be associated. Other retrospective studies have noted a younger mean age for NDE: 32 years,9 29 years,6 and 22 years.11 Cardiac arrest was the cause of the experience in most patients in Sabom's8 study, whereas this was the case in only a low percentage of patients in other work. We saw that people surviving CPR outside hospital (who underwent deeper NDE than other patients) tended to be younger, as were those who survived cardiac arrest in a first myocardial infarction (more frequent NDE), which indicates that age was probably decisive in the significant relation noted with those factors.
In a study of mortality in patients after resuscitation outside hospital,18 chances of survival increased in people younger than 60 years and in those undergoing first myocardial infarction, which corresponds with our findings. Older people have a smaller chance of cerebral recovery after difficult and complicated resuscitation after cardiac arrest. Younger patients have a better chance of surviving a cardiac arrest, and thus, to describe their experience. In a study of 11 patients after CPR, the person that had an NDE was significantly younger than other patients who did not have such an experience.19 Greyson7 also noted a higher frequency of NDE and significantly deeper experiences at younger ages, as did Ring.1
Good short-term memory seems to be essential for remembering NDE. Patients with memory defects after prolonged resuscitation reported fewer experiences than other patients in our study. Forgetting or repressing such experiences in the first days after CPR was unlikely to have occurred in the remaining patients, because no relation was found between frequency of NDE and date of first interview. However, at 2-year follow-up, two patients remembered a core NDE and two an NDE that consisted of only positive emotions that they had not reported shortly after CPR, presumably because of memory defects at that time. It is remarkable that people could recall their NDE almost exactly after 2 and 8 years.
Unlike our results, an inverse correlation between foreknowledge and frequency of NDE has been shown.1,8 Our finding that women have deeper experiences than men has been confirmed in two other studies,1,7 although in one,7 only in those cases in which women had an NDE resulting from disease.
The elements of NDE that we noted (table 2) correspond with those in other studies based on Ring's1 classification. Greyson20 constructed the NDE scale differently to Ring,1 but both scoring systems are strongly correlated (r=0·90). Yet, reliable comparisons are nearly impossible between retrospective studies that included selection of patients, unreliable medical records, and used different criteria for NDE,12 and our prospective study.
Our longitudinal follow-up research into transformational processes after NDE confirms the transformation described by many others.1-3,8,10,13-16,21 Several of these investigations included a control group to enable study of differences in transformation,14 but in our research, patients were interviewed three times during 8 years, with a matched control group. Our findings show that this process of change after NDE tends to take several years to consolidate. Presumably, besides possible internal psychological processes, one reason for this has to do with society's negative response to NDE, which leads individuals to deny or suppress their experience for fear of rejection or ridicule. Thus, social conditioning causes NDE to be traumatic, although in itself it is not a psychotraumatic experience. As a result, the effects of the experience can be delayed for years, and only gradually and with difficulty is an NDE accepted and integrated. Furthermore, the longlasting transformational effects of an experience that lasts for only a few minutes of cardiac arrest is a surprising and unexpected finding.
One limitation of our study is that our study group were all Dutch cardiac patients, who were generally older than groups in other studies. Therefore, our frequency of NDE might not be representative of all cases--eg, a higher frequency could be expected with younger samples, or rates might vary in other populations. Also, the rates for NDE could differ in people who survive near-death episodes that come about by different causes, such as near drowning, near fatal car crashes with cerebral trauma, and electrocution. However, rigorous prospective studies would be almost impossible in many such cases.
Several theories have been proposed to explain NDE. We did not show that psychological, neurophysiological, or physiological factors caused these experiences after cardiac arrest. Sabom22 mentions a young American woman who had complications during brain surgery for a cerebral aneurysm. The EEG of her cortex and brainstem had become totally flat. After the operation, which was eventually successful, this patient proved to have had a very deep NDE, including an out-of-body experience, with subsequently verified observations during the period of the flat EEG.
And yet, neurophysiological processes must play some part in NDE. Similar experiences can be induced through electrical stimulation of the temporal lobe (and hence of the hippocampus) during neurosurgery for epilepsy,23 with high carbon dioxide levels (hypercarbia),24 and in decreased cerebral perfusion resulting in local cerebral hypoxia as in rapid acceleration during training of fighter pilots,25 or as in hyperventilation followed by valsalva manoeuvre.4 Ketamine-induced experiences resulting from blockage of the NMDA receptor,26 and the role of endorphin, serotonin, and enkephalin have also been mentioned,27 as have near-death-like experiences after the use of LSD,28 psilocarpine, and mescaline.21 These induced experiences can consist of unconsciousness, out-of-body experiences, and perception of light or flashes of recollection from the past. These recollections, however, consist of fragmented and random memories unlike the panoramic life-review that can occur in NDE. Further, transformational processes with changing life-insight and disappearance of fear of death are rarely reported after induced experiences.
Thus, induced experiences are not identical to NDE, and so, besides age, an unknown mechanism causes NDE by stimulation of neurophysiological and neurohumoral processes at a subcellular level in the brain in only a few cases during a critical situation such as clinical death. These processes might also determine whether the experience reaches consciousness and can be recollected.
With lack of evidence for any other theories for NDE, the thus far assumed, but never proven, concept that consciousness and memories are localised in the brain should be discussed. How could a clear consciousness outside one's body be experienced at the moment that the brain no longer functions during a period of clinical death with flat EEG?22 Also, in cardiac arrest the EEG usually becomes flat in most cases within about 10 s from onset of syncope.29,30 Furthermore, blind people have described veridical perception during out-of-body experiences at the time of this experience.31 NDE pushes at the limits of medical ideas about the range of human consciousness and the mind-brain relation.
Another theory holds that NDE might be a changing state of consciousness (transcendence), in which identity, cognition, and emotion function independently from the unconscious body, but retain the possibility of non-sensory perception.7,8,22,28,31
Research should be concentrated on the effort to explain scientifically the occurrence and content of NDE. Research should be focused on certain specific elements of NDE, such as out-of-body experiences and other verifiable aspects. Finally, the theory and background of transcendence should be included as a part of an explanatory framework for these experiences. <hr></blockquote>
It's just occurred to me that there's no reason why I can't quote the study's conclusions right here. And THT - note that it does mention ketamine</strong>
It's good that you quoted it here since I was not willing to register on the Lancet website. Thank you.
I don't know. Doesn't seem that controversial to me. They maybe jumping to some conclusions and eliminating causes too much, but they are really saying that much.
<strong>[qb]Originally posted by The Blue Meanie:
It's just occurred to me that there's no reason why I can't quote the study's conclusions right here. And THT - note that it does mention ketamine</strong>
It's good that you quoted it here since I was not willing to register on the Lancet website. Thank you.
I don't know. Doesn't seem that controversial to me. They maybe jumping to some conclusions and eliminating causes too much, but they are really saying that much.[/QB]<hr></blockquote>
"They are really saying that much"? Nice of you to admit that
I'm with you on having to register at sites. It's a real pain, and I normally use false information