British near-death expert, Dr. Sam Parnia, discussed his work as a critical-care physician and the NDE research that led him to write What Happens When We Die. As part of his study, Parnia examined the accounts of cardiac arrest patients who were brought back from clinical death. According to Parnia, between 10- and 20-percent of these patients claimed to have had near death experiences.
Parnia detailed some common elements of NDEs, which include a feeling of peacefulness, seeing a bright light or tunnel, meeting with deceased relatives, and going through a life review. He said reports of NDEs go back as far as Plato, who described near death experiences in the Republic. Artist Hieronymus Bosch also dealt with NDEs in his work, Parnia explained, describing one of Bosch's paintings that depicts a tunnel of light with angels escorting the newly departed to the other side.
Parnia cited cases of patients who allegedly rose above their bodies while on the operating room table to see and hear everything the doctors were doing to them. He also talked about an experiment he conducted using 'targets' that could only be seen by looking down from the ceiling in an effort to prove whether or not these patients were really having out of body experiences. Parnia said he has not yet gathered a large enough sample to draw any useful results from the experiment. While he could not say conclusively whether these experiences prove the existence of an external reality, Parnia said "people of all backgrounds [including atheists] have near death experiences."