IT IS a phenomenon that has been reported many times but never proved for certain. Like UFO sightings, many people have said they can remember episodes after clinically dying - known as near-death experiences - but science has so far failed to find out whether it really occurs.
Now a scientific investigation into life after death is being done by a nurse at one of Wales's busiest intensive care units. Penny Sartori has been given ethical approval to help examine what happens when critically ill patients have a "near-death experience" (NDE).
Working at Morriston Hospital in Swansea, she has so far detailed 50 accounts from accident and heart attack victims and other patients who have almost died but survived.
Nearly all described floating above the resuscitation room, walking into a bright light in a loving atmosphere and seeing dead relatives before being told to "go back".
But one woman patient reported a "hellish" experience, being surrounded by dark, frightening shapes.
Mrs Sartori's work is being super-vised by Britain's leading clinical authority on near-death experiences, Dr Peter Fenwick, an internationallyrenowned neuropsychiatrist and Fellow of the Royal College of Psychiatrists.
He is leading research into whether near-death experiences are mere hallucinations caused by drugs, or a true glimpse of an afterlife.
After a study at Southampton General Hospital where 60 seriously ill patients reported the phenomena he looked for more research. Mrs Sartori agreed to help.
She said, "When I started working in the intensive care unit where I was obviously surrounded by death and serious illness it made me want to find out if there really was anything after death."
The Swansea project has involved "marker" cards being placed on top of cupboards in the Morriston intensive care unit. But none of the patients who said they had floating-type near-death experiences reported looking down and seeing the cards.
However, Mrs Sartori, 31, of Uplands, Swansea, does not believe this disproves any genuine transcendental experience.
She said, "Because we monitor patients' heart and brain activity very closely in the unit we know exactly their levels of consciousness.
"I know from personal experience that a number of patients who reported exactly the resuscitation actions of doctors and nurses were deeply unconscious at the time.
"That means they could not have dreamt or seen the experience and most patients would not know anything about emergency procedures.
"I don't think the fact NDE patients did not report seeing the marker cards disproves anything. Most of them said they floated in directions away from the cupboards and some said they did not float directly over them."
In follow-up studies the nurse has found that in almost all cases, NDEs have a life-changing effect on those who go through them.
She said, "The lady who had a negative experience, a religious minded lady, did not want to speak about it after initially explaining it.
"But many want to talk and talk about it and they say it has changed their outlook on life positively, making them less afraid of death and generally happier."
Mrs Sartori is coming close to the end of her research and plans to draw up her conclusions for Dr Fenwick later this year.