From ABC America : "It's an unusual area of science, but after a patient described mysterious experiences and feelings during a close brush with death, Dr. Kevin Nelson knew he wanted to learn more.
"'It was so vivid to him. I was struck by the intensity of the report he gave me,' Nelson said of the patient's near-death experience, which occurred when Nelson was a medical intern.
"He and his team of researchers discovered that the near-death study group had a significantly higher rate (60 percent compared with 24 percent) of a sleep disorder known as rapid eye movement, or REM, intrusion.
"This disorder causes one of the most active dream states of sleep -- REM -- to intrude into wakefulness, causing a person to sometimes wake up and feel paralyzed, experience leg muscle weakness or wake up to hear sounds other people didn't."