DOCTORS believe they may have found the cause of the powerful spiritual experiences reported by people “brought back from the dead”.
A study of the brainwaves of dying patients showed a surge of electrical activity in the moments before their lives ended.
The researchers suggest this surge may be the cause of near-death experiences, the mysterious medical phenomena in which patients who have been revived when close to death report sensations such as walking towards a bright light or a feeling that they are floating above their body.
Many people experience the sensation as a religious vision and treat it as confirmation of an afterlife. However, the scientists behind the new research believe that is wrong. “We think the near-death experiences could be caused by a surge of electrical energy released as the brain runs out of oxygen,” said Lakhmir Chawla, an intensive care doctor at George Washington University medical centre in Washington.
“As blood flow slows down and oxygen levels fall, the brain cells fire one last electrical impulse. It starts in one part of the brain and spreads in a cascade and this may give people vivid mental sensations.”
Many revived patients have reported being bathed in bright light or suffused with a sense of peace as they start to walk into a light-filled tunnel. A few even say they experienced visions of religious figures such as Jesus or Muhammad or Krishna, while others describe floating above their own deathbed, observing the scene.
In one of the most famous cases, in 1991, Pam Reynolds, an American singer, reported watching the top of her own skull being removed by surgeons before she moved into a bright glowing realm, including detailed accounts of the surgery and the conversations by her surgeons.
If Chawla is right, however, such experiences have a biological explanation rather than a metaphysical one. In the research he used an electroencephalograph (EEG), a device that measures brain activity, to monitor seven terminally ill people.
The medical purpose of the devices was to make sure that the patients, suffering from conditions such as cancer and heart failure, were sufficiently sedated to be out of pain. However, Chawla noticed that moments before death the patients experienced a burst in brainwave activity lasting from 30 seconds to three minutes.
The activity was similar to that seen in people who are fully conscious, even though the patients appeared asleep and had no blood pressure. Soon after the surge abated, they were pronounced dead.
Chawla’s research, published in the Journal of Palliative Medicine, is thought to be the first to suggest that near-death experiences have a particular physiological cause. Although it describes only seven patients, he says he has seen the same things happening “at least 50 times” as people die.
Other scientific studies suggest that 15%-20% 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 encounter with death.
In Britain, such research has prompted the launch of the Awareness During Resuscitation study, known as Aware, led by Sam Parnia, an intensive care physician at Cornell Medical Center in New York, who is also a researcher at Southampton University's school of medicine.
Parnia believes Chawla’s research is interesting, but treats its conclusions with caution, pointing out that there is no proof that the electrical surge observed by Chawla is linked to a near-death experience.
“Since the patients all died, we cannot tell what they were experiencing,” he said.
Parnia and his colleagues are interviewing 700 Britons who have had cardiac arrests and been brought back to life. The aim is to study all the mental consequences of cardiac arrests, ranging from near-death experiences to long-term cognitive disabilities.
“We see death as a moment, but actually it is a process and one which modern medicine can often reverse,” said Parnia. “Death starts when the heart stops beating, but we can intervene and bring them back to life, sometimes even after 3-4 hours when people are kept very cold.
“It could be that a far higher proportion of people have near-death experiences but just don’t remember them.”
Those who do remember such phenomena, however, can find their lives transformed. One Dutch study, published in 2001 in The Lancet, the medical journal, looked at 344 cardiac arrest victims, finding that 18% of them underwent near-death experiences.
The researchers followed surviving patients for several years, finding that those who had had a near-death experience became happier, more altruistic, less afraid of death and less materialistic.
Chawla says the study is an important first step in understanding near-death experiences but is now planning further research using much more advanced EEG machines to see if he can confirm a link between the observed surge in brain activity and patients’ experiences.