Near-death experiences

When doctors returned to check on the patient who had almost died and been in a deep coma before being resuscitated, he thanked them for all the work they had done. He had, he told the surprised team of medics, been very impressed and had watched everything they had done. He had heard all that had been said, too, and, at one point, had been concerned when resuscitation was about to be abandoned. He then went on to describe in detail the room where he had been treated – although he had never been conscious in there.

That near-death experience is one of a number recorded by Dutch doctors and one of thousands of similar cases that have now been documented in a major worldwide study.

New research shows that many critically ill kidney dialysis patients have similar experiences, and that almost one in 10 heart-arrest survivors also report near-death experiences whose features include out of body sensations, bright lights, dark tunnels, and images of life events and spiritual entities.

But there's no consensus on what lies behind near-death experiences, even though they are being increasingly reported. Are they, as some people are convinced, signs of the soul leaving the body? Or are they, as others suggest, the last, dreamlike act put on by a dying brain?

The spiritual theorists have it that this is the immediate prelude to death itself, and that it establishes that there is life after death. These theories take what the individual sees, hears and feels as being a report of exactly what happened. One suggestion is that, at the time of death, the body and soul separate and near-death experiences are a glimpse of the first part of that process.

A range of psychological theories have been put forward to explain the phenomenon. One suggests that it is a defence mechanism in the face of impending death. Another floats the idea that the working of the brain is somehow altered by changes in chemicals that occur shortly before death. Other explanations include false memories, a reaction to acute stress, and anoxia, or lack of oxygen, resulting in sensory disturbances.

A newer theory suggests the arousal system is implicated, and that the near-death experience is triggered by the crisis. The idea is that rapid eye movement (or REM sleep, where most dreaming occurs, and where the sleeper is paralysed, with only the heart, diaphragm, eye muscles and the smooth muscles active) is involved. At the root of the theory is the notion that some people are more prone to a condition called REM intrusion, where sleep paralysis occurs when they are awake. It is found in people with narcolepsy, or excessive sleepiness, and it can be accompanied by hallucinations or delusional experiences that are unusually vivid and often frightening.