Washington, Sept 15 : While people often claim to have seen a bright light at the end of a long dark tunnel following a near-death experience, an international research team has launched a new study to determine what really happens when people have a brush with death.
The new study titled AWARE (AWAreness during REsuscitation) will involve patients who reach a state called cardiac arrest.
The researchers will study what happens to the brain and consciousness when someone is on the verge of dying, whether it is possible for people see and hear during cardiac arrest, and what's going on during out of body experiences.
"Contrary to popular perception, death is not a specific moment," Live Science quoted lead researcher Dr. Sam Parnia of the University of Southampton in the UK as saying.
"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," he added.
The scientists have long been studying the precise moment when the death occurs.
A person is thought to have died when he stops breathing, his heart stops beating, and his brain activity ceases.
"During a cardiac arrest, all three criteria of death are present," Parnia said.
"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," he added.
Previous research have shown that about 10 to 20 percent of people who live through cardiac arrest report lucid, well-structured thought processes, reasoning, memories and sometimes detailed recall of events during their near death experience.
One study had found that people who reported peaceful feelings, bright light and out-of-body experiences during a brush with death are more likely to have had difficulty separating sleep from wakefulness in their everyday lives.
Both before and after their near-death experiences, these people often have symptoms of the rapid-eye movement (REM) state of sleep while awake.