"Contrary to popular perception, death is not a specific moment," said Sam Parnia, MD, an expert in the field of near-death research and the leader of the AWARE Study, launched by the University of Southhampton's Human Consciousness Project.
"It is a process that begins when the heart stops beating, the lungs stop working, and the brain ceases functioning---a medical condition termed cardiac arrest, which from a biological viewpoint is synonymous with clinical death. During a cardiac arrest, all three criteria of death are present. There then follows a period of time, which may last from a few seconds to an hour or more, in which emergency medical efforts may succeed in restarting the heart and reversing the dying process. What people experience during this period of cardiac arrest provides a unique window of understanding into what we are all likely to experience during the dying process."
A number of recent scientific studies carried out by independent researchers have demonstrated that 10 to 20 percent of people who go through cardiac arrest and clinical death report lucid, well-structured thought processes, reasoning, memories and sometimes detailed recall of events during their experience. During the AWARE Study, doctors use sophisticated technology to study the brain and consciousness during cardiac arrest.
Source: University of Southampton press release, September 2008