For years people who have talked of having an out-of-body near-death experience have been dismissed as crackpots or attention seekers. But a new study reveals that one in 10 heart-attack victims have spoken of just such an episode which left them feeling either at peace or at the gates of hell.
When the first explanation for near-death experiences came, it seemed straightforward.
According to scientists the cause was anoxia, when the brain is starved of oxygen.
Caroline Watts of Edinburgh University explained: "Cells in the visual cortex of the brain are dying off and some are firing randomly.
"It has been argued that this causes flashes of circles which appear to be a tunnel with a light at the end to the person experiencing them."
"People who have experienced near-death experiences - NDEs - often say it is pleasant.
"But if you are near death or injured your body releases endorphins, which are the body's natural opiates, which help to produce the serene and peaceful feelings associated with NDEs."
However, a recently completed 13-year study conducted in Dutch hospitals appears to turn this theory on its head.
According to the man in charge of it, Dr Pim van Lommel, anoxia cannot be the sole explanation as only 18 per cent of heart attack victims experienced an NDE.
If the theory was correct, he argued, all patients who were later revived should have had one. This has led Dr van Lommel and other medical professionals to speculate that the mind can operate independently from the brain.
One of the striking things about NDEs is how similar they are.
In cardiac victims they often start with the feeling of floating out of the body and viewing ongoing medical efforts to save them.
This is followed by a voyage through a dark or black tunnel towards a bright light and accompanied by feelings of love and peace. Sometimes there is a review of your life.
Many report meeting either a supernatural being, such as God, or dead relatives who tell them it's not their time to die and to go back. People who experience this type of NDE subsequently no longer fear death.
However, sometimes people are dragged or fall down the tunnel towards a black nothingness away from the bright light. This void is described as a place full of fear, pain and terror. Not surprisingly, these people fear death afterwards.
A study was lead by cardiologist Pim van Lommel, MD, and set up in ten different hospitals in Holland over a period of 13 years. In this time period, 344 patients who had cardiac arrest were successfully resuscitated and they were then shortly after interviewed about their experience of being near to death. The study found that of the 344 patients, 62 patients or 18 percent reported having a near-death experience.
This prospective study gives strong evidence that near-death experiences are not just stories that people make up, but that something does indeed happen to people who come close to death. Still, many experts remain skeptical. One attempt to explain the near-death phenomenon is that the experience is simply due to hallucinations brought on by the loss of oxygen to the brain, which in medical term is called "anoxia."
However, this explanation is a bit problematic because as we all know people who collapse or faint usually have total blackout or are at least very confused about what happened to them. But the near-death experiencer has a clear consciousness of the event, remembering the episode acutely for many years. So, the big question for the skeptics is; how can people have clear consciousness in a state of cardiac arrest with no brain activity (flat EEG)? Clearly these cases should not be called near death experiences but life after death experiences because people with cardiac arrest are clearly dead with no breathing or heart beat.
"Interestingly, NDEs are like religious conversion experiences. "Many of those who become born-again into a religion report they no longer fear death."
Ann Winsper, a North parapsychologist, said: "Many theories have been put forward to explain NDEs in purely "scientific" terms. However, for every theory proposed there have been scientific studies of cases that do not fit the proposed explanation.
"Death is usually accepted once a patient has a flat EEG (Electro Encephalography) reading . . . brain death equates with death of the individual.
"However there are documented studies of patients having accurate impressions of events that took place while their brains showed a flat EEG, and they were clearly dead.
"This has enormous implications. Does it imply that consciousness continues after death, and does this confirm that NDEs are not simply the last gasps of a dying brain, but transition to an afterlife?
"So far, we just don't know."