Near-Death Experiences Unraveled in World's Largest Study of Human Consciousness

Scientists have taken a closer look at the experience of death. After a four-year international study of 2,060 cardiac arrest cases, they've found that the themes relating to the experience of death are far broader than what has been understood so far, or what has been described as so-called near-death experiences.

Recollections in relation to death, also known as out-of-body experiences (OBEs) or near-death experiences (NDEs), have often been considered hallucinatory or illusory in nature. Yet objective studies in relation to these experiences have been limited. That's why scientists decided to dig a bit deeper in order to find out the nature of these experiences.

In 2008, a large-scale study involved 2,060 patients was launched. Known as the AWARE (AWAreness during Resuscitation) study, it tested the validity of conscious experiences using objective markers for the first time.

"Contrary to perception, death is not a specific moment but a potentially reversible process that occurs after any severe illness or accident causes the heart, lungs and brain to cease functioning," said Sam Parnia, one of the researchers, in a news release. "If attempts are made to reverse this process, it is referred to as 'cardiac arrest'; however, if these attempts do not succeed it is called 'death.' In this study we wanted to go beyond the emotionally charged yet poorly defined term of NDEs to explore objectivity what happens when we die."

While 39 percent of patients who survived cardiac arrest were able to describe a perception of awareness, they did not have any explicit recall of events. This, in particular, suggests more people may have mental activity initially but then lose their memories after recovery. Among those who reported awareness, 46 percent experienced a broad range of mental recollections that weren't compatible with the commonly used term of NDEs; these included fearful and persecutory experiences. Only 9 percent had experiences compatible with NDEs and 2 percent exhibited full awareness compatible with OBEs.

One case in particular was validated and timed using auditory stimuli during cardiac arrest.

"This is significant, since it has often been assumed that experiences in relation to death are likely hallucinations or illusions, occurring either before the heart stops or after the heart has been successfully restarted, but not an experience corresponding with 'real' events when the heart isn't beating," said Parnia. "In this case, consciousness and awareness appeared to occur during a three-minute period when there was no heartbeat."

The findings reveal a bit more about near-death experiences. More specifically, it shows that people can sense what's going on around them, even while the heart is stopped. Currently, scientists hope to conduct further studies to explore whether awareness may lead to long term adverse psychological outcomes, including post-traumatic stress disorder.

The findings are published in the journal Resuscitation.