A tunnel with a bright light at the end, your own life passing you by or even out-of-body experiences: some people were very close to death and yet returned to life. Her memory of the moment the heart stops beating is fascinating - and it has fascinated scientists for years. Because behind this lies perhaps one of humanity's oldest questions: What do we experience when we die?
A few months ago, US researchers published that brain activity increases rapidly when a dying patient is removed from life support devices. In addition, the scientists used animal experiments to find that the nerve cells can recover significantly longer after such an incident than previously assumed.
These theses have now been confirmed by a new study: A team of researchers from New York University led by cardiologist Sam Parnia examined a total of 567 patients between May 2017 and March 2020 after they had suffered a cardiac arrest. They were hooked up to an electroencephalogram (EEG) to measure their brain activity.
At the same time as the examination, resuscitation measures were carried out to get the heart beating again. Only ten percent of the people studied survived this scenario. 28 of them were then able to be interviewed about their experiences. The researchers also interviewed 126 additional subjects who had suffered a cardiac arrest outside of a hospital and survived.
40 percent of those surveyed said they could remember the moment of cardiac arrest and the resuscitation measures. For example, they report physical pain such as pressure on the chest - either as a real-looking experience or as dream-like.
They also reported “classic” near-death experiences such as going through a tunnel, reviewing their own lives, or going to a “pleasant place with light,” but then turning around and “returning.” Objectively, these reports are difficult to verify.
However, the examinations of the patients in the hospital have shown astonishing things: in 40 percent of those examined, in whom no measurable brain activity could be temporarily detected, this returned after a certain period of time. And this in such a way that it can be concluded that consciousness is functioning, according to the researchers. In some cases, these activities only occurred 60 minutes after resuscitation began.
Whether the activities can actually be classified as consciousness is controversial among scientists. However, it is clear to the authors of the study that the findings should be taken into account in future treatments for possible brain damage. "It was previously assumed that the brain suffered irreversible damage ten minutes after the oxygen supply was interrupted due to cardiac arrest. However, our study shows that the brain can restore its electrical activity much later," explained Parnia.
A typical motif that people with near-death experiences report is seeing their own life flash before their mind's eye. It is still not clear why so many people affected report this. For the authors of the study, this could be due to the fact that the barriers that are normally installed in the brain to prevent memories and thoughts from flowing uninterrupted dissolve in the dying process. It is possible that dying people would reach a level of consciousness that is the same for all people, but is only accessible shortly before death, according to the researchers.
As the "Standard" reports, the research findings are "remarkable" for intensive care physician Lakhmir Chawla, who himself researches EEG activities. He told Scientific American magazine that he was convinced that patients should be treated "as if they were awake" during resuscitation measures.
Even if a patient cannot be saved, he believes family or friends should be allowed to be with the patient in the last minutes of life, because they may be able to hear or perceive them.
Sources: Study, "Der Standard", "Scientific American"