Wednesday October 8 2014
Near-death experiences: visions of the afterlife or hallucinations?
“Life after death is a real phenomenon,” Metro reports – but the headline is pure hype. Researchers were actually looking at “near-death experiences” – a very different thing. Indeed, the research involved people who did not die (even “technically”).
Near-death experiences are reported by people claiming to have had experiences when they were close to death, such as when their heart stops during a cardiac arrest.
Reported near-death experiences can range from the mystical (seeing a bright light) or having an out-of-body experience (feeling like you’re floating above your body), to the disturbing (a drowning sensation).
The study involved 140 people who had recovered from a cardiac arrest. Of these, 55 reported having a near-death experience during their cardiopulmonary resuscitation (CPR).
To assess the accuracy of claims of “out-of-body experiences”, researchers put shelves in hospital rooms where cardiac arrests were likely to occur, and placed one image on each shelf that could only be seen from above. One person recalled looking down from the top corner of the room. His descriptions appear to be accurate, but cannot be validated as his treatment occurred in an area without the shelves and pictures.
This study certainly does not provide proof of life after death. It suggests, but provides little evidence, that levels of awareness during CPR may be higher than expected.
Where did the story come from?
The study was carried out by researchers from the State University of New York at Stony Brook, the University of London, the University of Southampton and various other UK, US and Austrian Universities. It was funded by Resuscitation Council (UK), the Nour Foundation and the Bial Foundation.
The Bial Foundation says its mission is to “foster the scientific study of the human being from both the physical and spiritual perspectives”.
The Nour Foundation says that its “central goal” is to “stimulate an objective and intelligent discourse on existential questions from an unbiased and interdisciplinary perspective that is rooted not only in theories, but in shared commonality of personal experience as well.”
The study was published in the peer-reviewed medical journal Resuscitation.
The media have all reported that these experiences occurred when the brain had “stopped” or “completely shut down”, when in fact all the people in the study were receiving CPR during the time of the experience, and so had oxygenated blood being pumped around their brain. Therefore, none of the claims around proof of an “afterlife” are strictly true.
A more accepted definition of death is when brain stem death occurs, which is when all neural activity in the deepest brain ceases. While it is possible to keep the heart functioning using life support systems, a person with brain stem death has permanently lost the potential for consciousness.
The existence of an “afterlife” remains a matter of belief, not scientific proof.
What kind of research was this?
This was an observational study that aimed to objectively assess reports of awareness and the broad range of mental experiences during CPR, including out-of-body experiences.
What did the research involve?
15 hospitals in the US, UK and Austria participated in the study between July 2008 and December 2012. To assess reports that people can look down on themselves from above, the hospitals installed shelves in places where cardiac arrests were likely to occur, such as the emergency department and acute medical wards, and placed one image on each shelf that could only be seen from above. These images included nationalistic and religious symbols, people, animals and major newspaper headlines. A triangle was placed on the underside of the shelf, so that they could assess whether patients looked up after recovery or had had their eyes open during cardiac arrest.
Participants were over 18 and had had a cardiac arrest – defined as no heartbeat or breathing, in or out of hospital with cardiopulmonary resuscitation (CPR) still occurring by the time they were in the emergency department. They had to be considered unconscious with a Glasgow Coma Scale Score of 3/15, meaning that they were unresponsive to pain. If they survived, and were well enough to be interviewed according to their doctor and family, then they were asked to participate.
A research nurse conducted a first general interview, preferably when the person was still in hospital, but some interviews were conducted over the phone. The second interview included the 16-point Greyson Near Death Experience (NDE) Scale, which asks questions including:
- Did you have the impression that everything happened faster or slower than usual?
- Did scenes from your past come back to you?
- Did you see, or feel surrounded by, a brilliant light?
- Did you see deceased or religious spirits?
An in-depth interview was conducted in those people who had detailed visual and sound experiences while they had a cardiac arrest.
What were the basic results?
There were 2,060 recorded cardiac events, and 330 people (16%) survived to hospital discharge. An interview was possible for 140 of them, and 101 completed two interviews. All of those who reported a near-death experience had at least two interviews, while nearly half of those who reported no such experience dropped out after the first interview.
The inpatient interviews took place between three days and four weeks after the event and the telephone interviews took place between three months and a year after the event.
There were 55 people (39%) who remembered something from the time that they were considered to be unconscious. There were no significant differences in age or sex between people who remembered something and those that didn’t.
Of the 101 people who completed the Greyson NDE Scale:
- 27 had the impression that everything happened faster or slower than usual
- 22 had a feeling of peace or pleasantness
- 13 felt their senses were more vivid than usual
- 13 felt separated from their body
Nine people experienced enough of the items on the scale strongly enough that they were classified as having a near-death experience.
Seven of these people had no auditory (sound) or visual recall, whilst the remaining two people described full visual and sound awareness. One was unable to complete an in-depth interview due to ill health, but the other male participant, aged 57, recalled looking down from the top corner of the room.
His descriptions of the people, sounds and the use of a defibrillator twice during his resuscitation appeared to be accurate, according to his medical records.
Unfortunately, his cardiac arrest occurred in an area without the pictures and the shelves (as did 78% of the cardiac arrests in the study), so the researchers were unable to determine whether he actually did have an out-of-body experience.
How did the researchers interpret the results?
The researchers concluded that people who survived cardiac arrest “commonly experience a broad range of cognitive themes, with 2% exhibiting full awareness. This supports other recent studies that have indicated consciousness may be present despite clinically undetectable consciousness. This together with fearful experiences may contribute to PTSD [post-traumatic stress disorder] and other cognitive deficits” following cardiac arrest."
This study set out to objectively test reports of awareness and the broad range of mental experiences during CPR, including people being able to look down at their body from above.
The study found that 39% of the survivors who agreed and were well enough to be interviewed remembered experiences while they appeared to be unconscious during CPR. This is probably due to the fact that although the participants had no heartbeat or spontaneous breathing, they were all receiving CPR, which means that their brains were still receiving oxygenated blood.
Only two people described full visual and sound awareness, and one of these was well enough to be interviewed, and described events in line with his medical records.
Other limitations of the study noted by the authors include:
- potential recall bias due to the amount of time between the event and when the interviews were able to be conducted
- the limited number of people who survived and had memories of the event
- the small number of people meant that they were not able to adjust the results for other possible confounders, which could have impacted on the blood flow in the brain. These include the length of time the cardiac arrest continued, the quality of the resuscitation, whether it happened in or out of hospital, the heart rhythm and the use of hypothermia during the cardiac arrest
It is perfectly plausible that people would continue to have thoughts and experiences while there is still oxygenated blood flowing to the brain.
Overall, this study provides no evidence to support the existence of an afterlife, merely that people near death may still have memorable experiences.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.