NEW YORK, Aug. 29 -- The question that opened the AWARE II study was not a metaphysical one. It was clinical. When the heart stops and brain activity flatlines, medicine treats that moment as the end of conscious experience. Dr. Sam Parnia and a team of researchers at NYU Langone Medical Center spent more than a decade testing whether that clinical assumption holds.

What they found, published in the journal Resuscitation Plus, is that it may not, at least not cleanly. Among 550 cardiac arrest survivors drawn from hospitals across the United States, the United Kingdom, Canada, and Austria, roughly a quarter reported recalled experiences during the period of clinical death. Those recollections were not random. They followed a structure so ...