Near Death Experience
The sensations reported by people who have recovered from traumatic, near-death circumstances such as during an operation or in casualty following a serious accident are varied and not completely consistent. It can range from out-of-body experiences (the sensation of floating above the action separate from one's own body), to 'light at the end of the tunnel' visions and even the common 'life flashing before me' type sensations. We commonly group these as 'Near Death Experiences' or NDEs. Many religious people use NDEs as evidence of an afterlife or for a soul. The explanation would be that the experience felt by the patient is real and is what she imagines it to be - the soul leaving its body, approaching a beatific light of an afterlife and being welcomed by a religious figure or missed dead loved-one.
US Psychiatrist Raymond Moody popularised the term in the 1970's (though there are countless reports from history and they may help explain the visions and hallucinations reported by many religious figures) According to Moody, the typical NDE includes a buzzing or ringing noise, a sense of blissful peace, a feeling of floating out of your own body and observing it from above, moving through a tunnel into a bright light, meeting dead people (saints, Jesus, angels or dead relatives) and finding it all so wonderful that you simply don't want to return to life.
Studies done by parapsychologists and psychologists, for example Caroline Watt, Susan Blackmore and Chris French, point to more prosaic answers. They point out many flaws with spiritual or transcendental explanations: The experience is by definition self-reported and open to all the cognitive biases familiar to skeptics; the reports are never cross-cultural (Baptists don't report seeing the Virgin Mary and Muslims don't see Vishnu) and there is no way to tell when in the recovery process these experiences actually occur to the patient because we rely on them reporting it once they recover. As Chris French has noted "the survivalist approach does not appear to generate clear and testable hypotheses. Because of the vagueness and imprecision of the survivalist account, it can be made to explain any possible set of findings and is therefore unfalsifiable and unscientific."