Parnia pointed out that aside from one reference to a 1950 text book which is out of print, nothing he's read in the medical literature has been able to mimic a near-death experience with a chemical. He made the analogy of the release of endorphins or hormones with a person who experiences love for their child.
"You can't say your love was a hallucination, because we find the chemical pathways that simulate love," said Parnia, who is based at Weill Cornell Medical Center in New York City and the University of Southampton in England. "If there is a chemical, that doesn't mean that the experience isn't real, it doesn't mean that he experienced a hallucination.
However, Parnia believes science can still test near-death experiences. Parnia leads the multi-institutional AWARE study by the Human Consciousness Project in which different hospitals around the world place "targets" or objects only visible from the ceiling in hospital rooms. When a patient who is resuscitated reports a near-death experience, including floating above the body, researchers check to see if they saw the object.
"We're actually going through the data now and we'll have an answer in a year's time," said Parnia. They have 700 cases to go through."