Why does a person experience sudden consciousness on the deathbed?

For decades, researchers, hospice caregivers, and family members of people with Alzheimer’s or other forms of dementia have witnessed people suddenly regain their lost memories and personalities just before death. This situation may seem like a second chance to family members, but to many experienced treatment staff, it can be a sign that the end of the person’s life is near.

Christopher Kerr, executive director and chief medical officer at the Hospice and Care Center in Buffalo, New York, has studied the phenomenon of consciousness at the time of death in hundreds of terminally ill patients. The phenomenon “usually occurs in the last few days of a person’s life,” he says. according to Andrew Petersona researcher of bioethics and consciousness from George Mason University, who has conducted research on this subject at the request of the National Institutes of Health, the phenomenon of “vigilance at the end of life” is defined as the unexpected return of cognitive abilities, such as speech and “communication” with other people.

This communication goes beyond the return of lost communication abilities and situational awareness. Peterson What seems so profound to family members observing a person’s consciousness is a state we call “emergent old age,” he says. There is a lot of evidence that these people are not only aware of their surroundings, but also know exactly how they relate to others. This ability is revealed by using a nickname or referring to an old joke.

As strange as these events may seem, they are very common. Jason Karlavish“Our study was not a cross-sectional study,” says gerontologist at the Penn Memory Center and senior researcher of the study. However, he adds, “What we found is that consciousness in patients with dementia is more common than the exception, which suggests that the idea that it’s the end of the road is not entirely correct.” Instead, he suggests that this consciousness should be considered part of the “illness experience” rather than an aberrant event. Karlovy Vary “We actually found that many different types of these events occurred months or even years before the person died,” he notes.

However, many experts including Chor And Prenia They agree that most of these events are directly related to a person’s approach to death. Prenia “It’s almost like these people are preparing themselves to die,” he says. The potential consequences of this broad and temporary cognitive renaissance are palpable. Peterson It notes that there may be residual neural networks or neural pathways and functions in the brain that could potentially help restore cognitive abilities in people thought to be permanently brain-impaired.

But research on this phenomenon is still in its early stages. Peterson “We don’t really know what process is going on in the brain during death that is somehow related to these events,” he says. Despite this uncertainty, further research into brain activity near death, or at the time of death, could provide scientists and doctors with more insight into some of the processes that take place in the brain of a sick or dying person.

At research Published in May in the Proceedings of the National Academy of Sciences (PNAS), University of Michigan researchers observed increased organized brain activity in two out of four people in a coma. These people suffered cardiac arrest after the life support devices were cut off. This research was based on more than a decade of research and study on animals.

One of these studies A study in PNAS It was in 2013 that showed a similar increase in concurrent brain activity in mice exposed to cardiotoxin. Also in Another study In 2015, the mice died of suffocation. In all of these studies, researchers found that gamma ray activity increased during the first few minutes of cardiac arrest and then stopped. Gamma rays are brain wave frequencies that are commonly associated with wakefulness, alertness, and memory recall.

Jimo Burjigin, a neurologist and associate professor of molecular and integrative physiology at the University of Michigan, has participated in all three studies. According to his observations, the growth of gamma waves in dying subjects, especially in an area of ​​the brain known as the “hot zone” posterior cortex» Known near the back of the skull, it was very intense. Some other researchers believe that this region may also be necessary in the context of conscious experiences.

Parts of the brain in the aforementioned area are related to visual, auditory and motor perception; A phenomenon that Borjigin believes is involved in the “out-of-body experiences” reported by people near death and recovering. He notes that patterns of gamma-ray activation, similar to those observed in comatose subjects, are associated with activities involving familiar image recognition (such as human faces) in healthy subjects.

In both human and animal studies, after the reduction of oxygen, the subjects’ brain activity suddenly increased. Borjigin “The brain to re-oxygenate this,” he says The mechanism of isostasis “It activates the heart, either by breathing harder or by making the heart beat faster.” Also, it is hypothesized that the increase in more complex brain activity observed in humans and animals that suffer cardiac arrest is also the result of the brain trying to re-establish homeostasis or biological balance after detecting a lack of oxygen.

also, Borjigin believes that this type of survival mechanism may also play a role in other changes in cognition around death. Consciousness at the time of death in dementia patients may be due to this kind of final effort in the brain, he adds. When physiological systems fail, the brain tries to save itself.