Near-death experiences are still partly shrouded in mystery. Mystical explanations aside, researchers from the University of Liège’s Coma Science Group and Liège CHU are attempting to elucidate the physiological and psychological processes likely to explain how they occur and how ‘experiencers’ experience them. In an article recently published in Consciousness and Cognition, they show that the emotions reported by patients with locked-in syndrome who have had a near-death experience, are less positive than those of other experiencers, but their autobiographical memories are richer.

Near-death experiences (NDE) are relatively frequent, with approximately 10 % of people having survived cardiac arrest reporting them. In addition, some people say they have had a NDE even though their life wasn’t in danger and they didn’t go through a period of coma at any moment. Hence, a syncope or extreme stress (for instance, when people escape a car accident with no serious injuries) are sometimes sufficient to cause an NDE, even if, in this case, the term isn't really appropriate.

The components of near-death experiences are highly spectacular. Indeed, it is characteristic to recall a feeling of intense well-being, of having the impression of leaving the body, seeing a bright light emerging from a tunnel-like dark spacel, losing the sense of time, visiting ‘another world’, being certain of having communicated with the dead or a mystical being, or a feeling of complete harmony with the universe. However, to be considered an ‘experiencer’ (someone who has had a near-death experience), it isn't necessary to have experienced all the characteristic phenomena of an NDE, just a certain number of them.

Neuroscientists and psychologists refer to specific scales to assess, as objectively as possible and in a standardised way, whether a subject has indeed had an NDE or not. The most commonly used one is the Greyson NDE scale. Exploring several aspects (cognitive, affective, paranormal, etc.), it is based on 16 questions with a score of 0, 1 or 2. A person can be said to have had an NDE if the total score obtained by an individual who answered the 16 questions is seven or more (out of 32).

Based on a cohort studied in 2014 (ref frontiers), the researchers found that the most reported feature is the feeling of well-being, followed by “out-of-body experiences” (OBE), seeing a brilliantbright light. In other words, NDE can have a variety of aspects. Vanessa Charland-Verville, an FNRS research fellow and a doctoral student in medical sciences in the University of Liège’s Coma Science Group and Liège CHU points out that NDE memories are most often interpreted through major cultural, philosophical and religious values.

Out-of-body experiences

The theories proposed to explain NDE can be grouped into three categories: spiritual, psychological and neurological.

Supporters of a spiritual explanation assert that these experiences prove the existence of a soul outside the body. They mainly support this theory based on the fact that one third of people who have had an out-of-body experience (OBE) state that they witnessed their resuscitation from above. During research carried out in Scandinavia, researchers decided to conceal images close to the ceiling of the operating theatre, that were invisible to a patient lying on the operating table. In 2008, a similar study was launched on an international level. It involved 25 hospitals. If the experiencers managed to confirm the presence of these hidden images on the ceiling, this would tend to prove that consciousness is probably separable from the body. For the time being, the issue has never been raised because no patient has ever reported seeing these images.