Patrick Coghlan was dying. He was peaceful and motionless, and his daughter, Mairead O’Connor, sat by his bedside, knowing the end was not far.

Suddenly — shockingly — he roused from his unconscious state, sat bolt upright, opened his eyes wide, and waved at something or someone only he could see.

Mrs O’Connor likes to think it was her late mother.

“His face looked radiant and happy,” she remembers.

“I knew I was witnessing something special.”

Moments later, he died.

For a long time, deathbed visions such as Mr Coghlan’s have been relegated to the realm of religion and superstition.

But increasingly, doctors are applying the rigours of science to a phenomenon they have seen too often to dismiss as the hallucinations of a failing mind.

One of those doctors is Australia’s Michael Barbato, a retired palliative care expert who has watched hundreds of patients pass away during his decades in medicine, and whose fascination with the mysteries of dying led him to conduct groundbreaking research into the behaviour of the brain at death.

Thirty patients at a Port Kembla hospital allowed palliative care researchers to put brain monitors on their head as they died, hoping to contribute to the scant knowledge of the dying brain. And the results are striking; they suggest that, for many people, the final seconds of life bring a last, powerful, surge of activity in the brain.

The resulting study, published this month in the Journal of Pain and Symptom management, found almost three quarters of the patients (73 per cent) had a spike in brain activity at the time of death.

“It is contrary to what one would expect,” said Dr Barbato.

“With impending death, the circulation slows, the heartbeat weakens, and the breathing gets slower or more irregular, but just as the heart beat and breathing case, the brain seems to have a burst of activity.”

Dr Barbato and his colleagues used bispectral (BIS) index monitoring, which is commonly used to measure sedation under anaesthetic. It has a 0-100 scale, where 100 is full awareness, 50 is deep sedation or sleep, and 0 is brain death.

Twenty-two patients had a spike from their baseline of an average 31 points. Ten of them had a spike of 40-50 points above their baseline. In only eight patients was the spike absent or smaller than 10 points.

“You see the line hovering at around 50, and all of a sudden it jumps to 80 or sometimes 90, almost consistent with the wide awake state, and then it drops right off to zero,” Dr Barbato said.

All patients had been given pain medication and none showed visible signs of awareness or discomfort.

Dr Barbato is cautious about his findings. More work, he says, is needed to show exactly what is happening. But these results, and evidence from other studies, suggest the spike might be due to a dream or vision.

“The only way to investigate this further is with a brain wave machine (EEG), although it would be hard to justify such a study involving dying patients,” he says.

“If other studies replicate our findings, then we should ask, ‘is this proof enough to conclude the surge is due to an end-of-life dream or vision, and if so, why do dreams and visions occur at the moment of death?'”

In 1926, deathbed visions crossed from superstition to science with a book by British Physicist William Barratt. He collected stories such as this one from a nurse who wrote about a woman suffering an aggressive and painful cancer.

“Suddenly her sufferings appeared to cease,” she said. “The expression on her face, which a moment before had been distorted by pain, changed to one of radiant joy. Gazing upwards, with a glad light in her eyes, she raised her hands and exclaimed, ‘oh mother dear, you have come to take me home. I am so glad!’ And in another moment, her physical life ceased.”

Deathbed visions, as described by Barratt and those who came after him, are different to near-death experiences, in which patients describe the sensation of leaving their body and being attracted to a bright light.

They are a comforting vision, often of friends or relatives, reassuring the patient that they will not be alone, and need not be afraid.

Barratt was one of the first to approach the subject scientifically, but it has taken another century for discussion of this subject — let alone clinical research into it — to be taken seriously by the medical community. Even now, many doctors and scientists consider the area too fringe, and too fraught.

“There’s a politics in science,” says Professor Allan Kellehear, an Australian-born expert and advocate in end-of-life care now working at the University of Bradford in the United Kingdom.

“One of the big problems with deathbed visions and near-death experiences and visions of the bereaved, is they prompt a very old debate between people with religious beliefs and materialists.”

Prof Kellehear’s own investigations have been rigorously scientific. His peer-reviewed research estimates that one in three deaths involve a vision, although others put the rate at 40 to 50 per cent.

He does not believe the visions are hallucinations — why would so many people see dying relatives on their deathbed, and not at other times? — and he does not think medication causes them.

But he also believes there is no empirical evidence to back up the theory that a near-death vision is the last flush of a dying brain.

“I have been researching dying for 30 years, as part of palliative care research, and the honest scientific answer is that we don’t know what they are,” he says. “But it’s important to reassure family that these are usually comforting things.”

During 30 years in palliative care, as a nurse and educator, Molly Carlile has seen many things that would make a lay person’s hair stand on end.

“Talk to any nurse who has worked in palliative care for any period of time, and they will be able to tell you stories about strange things,” she says.

Just recently, Ms Carlile’s mother-in-law died. She had always been afraid of death, but as it approached, accepted it calmly.

“I am not scared, I can see a door,” she said. “Can’t you see it? There’s a door, and there’s a hole in it, and the hole is beautiful, it’s full of life. That’s the door I am going through.” Soon afterwards, she died.

“Academics might say it’s all a coincidence,” Ms Carlile said. “When those sorts of experiences happen for families, it gives them a sense of comfort, a sense of meaning. It eases the traumatic nature of death, so why would you question it?

“It’s okay not to understand why it happens. There doesn’t have to be a double blind randomised control trial on every human experience to prove its validity. If it’s someone’s experience, then it’s their experience.”

As a country GP then palliative care specialist, Dr Barbato has witnessed hundreds of deaths. He has often seen sudden, dramatic returns to consciousness in patients that had been unconscious for days — a bright smile, a sudden stare, an extended hand to an empty corner of the room, before the patient lies back, and breathes their last.

He has watched the dying greet long-dead relatives as though they are in the room. He has seen patients hold on to life for days, waiting for a loved-one to reach their bedside, and die minutes later.

And he has seen others, often mothers, let go when their child has left the room briefly, perhaps protecting them to the last.

“That to me is the biggest mystery, the moment of death,” says Dr Barbato. “I have had people just sit up, dramatically — they are hardly alive, and they will sit up, and look straight ahead, and stay like that, as if they are staring. Within minutes, they will lie back again, and die.

“It is as though at the moment of death, something happens.”

These questions fascinate Dr Barbato. Why do we have visions as we die? Why do they happen to some, and not others? Is our subconscious somehow programmed to comfort us at the moment of our greatest uncertainty?

“I am not out to solve this mystery, but what I and my colleagues are trying to do is to learn more about dying,” he says.

So what does his study really mean?

“That’s the big question,” he says. “My belief is it does represent an alteration in the state of consciousness, rather than the agonal throes of a dying brain.

“What is happening in the unconscious to bring this experience to the fore in the moment of death?

Dr Barbato hopes there will be more studies on how the brain responds to death. Not to solve the mystery, but to help doctors understand dying so they can help patients and families better prepare for it.

Research is just a small part of Dr Barbato’s vocation. He was attracted to palliative care after the loss of his baby daughter, Moira, to SIDS, almost 40 years ago, an experience that still leaves his eyes teary and his voice shaking.

Now, having retired from clinical practice, he runs courses called Midwifing Death, hoping to teach carers how to support the dying, which, in its essence, involves being attuned to the needs of the dying person, and supporting them in the kind of death they want.

After a life devoted to death, Dr Barbato doesn’t believe in life after death — but he doesn’t reject the possibility, either.

“We are dealing with something that’s beyond rational thought,” he says. “I think the question of life after death is unknowable in its mystery. We will only know when we die.”

One thing Dr Barbato does know, however, is this. “If I have a vision when I die, if a hand is reaching out to me, I want it to be Moira’s.”