A near-death experience (NDE) is a profound personal experience associated with death or impending death which researchers describe as having similar characteristics. When positive, which the great majority are, such experiences may encompass a variety of sensations including detachment from the body, feelings of levitation, total serenity, security, warmth, joy, the experience of absolute dissolution, review of major life events, the presence of a light, and seeing dead relatives. When negative, such experiences may include sensations of anguish, distress, a void, devastation, vast emptiness, seeing hellish places and "the devil."
NDEs usually occur during reversible clinical death. Explanations for NDEs vary from scientific to religious. Neuroscience research hypothesizes that an NDE is a subjective phenomenon
resulting from "disturbed bodily multisensory integration" that occurs during life-threatening events. Some transcendental and religious beliefs about an afterlife include descriptions similar to NDEs.
In the U.S., an estimated nine million people have reported an NDE, according to a 2011 study in Annals of the New York Academy of Sciences. Most of these near-death experiences resulted from serious injury that affects the body or brain.
The equivalent French term expérience de mort imminente ("experience of imminent death") was proposed by French psychologist and epistemologist Victor Egger as a result of discussions in the 1890s among philosophers and psychologists concerning climbers' stories of the panoramic life review during falls.
In 1892, a series of subjective observations by workers falling from scaffolds, war soldiers who suffered injuries, climbers who had fallen from heights or other individuals who had come close to death (near drownings, accidents) was reported by Albert Heim. This was also the first time the phenomenon was described as a clinical syndrome.
In 1968, Celia Green published an analysis of 400 first-hand accounts of out-of-body experiences.