Tag: death process

Categories : Hospitals NeurologyTags :

New Evidence of Patients Recalling Death Experiences after Cardiac Arrest

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Up to an hour after cardiac arrest, some patients revived by cardiopulmonary resuscitation (CPR) had clear memories afterward of experiencing death and had brain patterns while unconscious linked to thought and memory, report investigators in the journal Resuscitation.

In a study led by researchers at NYU Grossman School of Medicine, some survivors of cardiac arrest described lucid death experiences that occurred while they were seemingly unconscious. Despite immediate treatment, fewer than 10% of the 567 patients studied, who received CPR in the hospital, recovered sufficiently to be discharged. Of the survivors, four in 10 recalled some degree of consciousness during CPR not captured by standard measures.

The study also found that in a subset of these patients, who received brain monitoring, nearly 40% had brain activity that returned to normal, or nearly normal, from a “flatline” state, at points even an hour into CPR. As captured by EEG, the patients saw spikes in the gamma, delta, theta, alpha, and beta waves associated with higher mental function.

Survivors have long reported having heightened awareness and powerful, lucid experiences, say the study authors. These have included a perception of separation from the body, observing events without pain or distress, and a meaningful evaluation of their actions and relationships. This new work found these experiences of death to be different from hallucinations, delusions, illusions, dreams, or CPR-induced consciousness.

The study authors hypothesise that the “flatlined”, dying brain removes natural inhibitory (braking) systems. These processes, known collectively as disinhibition, may open access to “new dimensions of reality,” they say, including lucid recall of all stored memories from early childhood to death, evaluated from the perspective of morality. While no one knows the evolutionary purpose of this phenomenon, it “opens the door to a systematic exploration of what happens when a person dies.”

Senior study author Sam Parnia, MD, PhD, associate professor in the Department of Medicine at NYU Langone Health and director of critical care and resuscitation research at NYU Langone, says, “Although doctors have long thought that the brain suffers permanent damage about 10 minutes after the heart stops supplying it with oxygen, our work found that the brain can show signs of electrical recovery long into ongoing CPR. This is the first large study to show that these recollections and brain wave changes may be signs of universal, shared elements of so-called near-death experiences.”

Dr Parnia adds, “These experiences provide a glimpse into a real, yet little understood dimension of human consciousness that becomes uncovered with death. The findings may also guide the design of new ways to restart the heart or prevent brain injuries and hold implications for transplantation.”

The AWAreness during REsuscitation (AWARE)-II study followed 567 adults who suffered in-hospital cardiac arrest between May 2017 and March 2020 in the US and UK. Only hospitalised patients were enrolled to standardise the CPR and resuscitation methods used, as well as recording methods for brain activity. A subset of 85 patients received brain monitoring during CPR. Additional testimony from 126 community survivors of cardiac arrest with self-reported memories was also examined to provide greater understanding of the themes related to the recalled experience of death.

The study authors conclude that research to date has neither proved nor disproved the reality or meaning of patients’ experiences and claims of awareness in relation to death. They say the recalled experience surrounding death merits further empirical investigation and plan to conduct studies that more precisely define biomarkers of clinical consciousness and that monitor the long-term psychological effects of resuscitation after cardiac arrest.

Source: Elsevier

Categories : Medical Research & TechnologyTags :

Do People’s Lives ‘Flash Before Their Eyes’ When They Die?

On By ModernMedia
Source: Pixabay CC0

By chance, neuroscientists were able to record the activity of a dying human brain and discovered brain wave patterns similar to dreaming, memory recall, and meditation. An analysis of this case, reported in Frontiers in Aging Neuroscience suggests a possible explanation for near-death experiences.

Imagine reliving your entire life in the space of seconds. Like a flash of lightning, you are outside of your body, watching memorable moments you lived through. This process, known as ‘life recall’, can be similar to what it’s like to have a near-death experience. What happens inside your brain during these experiences and after death are questions that have puzzled neuroscientists for centuries. However, the present study suggests that your brain may remain active and coordinated during and even after the transition to death, and may in fact be programmed to orchestrate the whole ordeal.

When an 87-year-old patient developed epilepsy, Dr Raul Vicente of the University of Tartu, Estonia and colleagues used continuous electroencephalography (EEG) to detect the seizures and treat the patient. During these recordings, the patient had a heart attack and passed away. This unexpected event allowed the scientists to record the activity of a dying human brain for the first time ever.

“We measured 900 seconds of brain activity around the time of death and set a specific focus to investigate what happened in the 30 seconds before and after the heart stopped beating,” said Dr Ajmal Zemmar, a neurosurgeon at the University of Louisville, US, who organised the study.

“Just before and after the heart stopped working, we saw changes in a specific band of neural oscillations, so-called gamma oscillations, but also in others such as delta, theta, alpha, and beta oscillations.”

Brain oscillations (aka ‘brain waves’) are patterns of rhythmic brain activity normally present in living human brains. These different types of oscillations, including gamma, are involved in high-cognitive functions, such as concentrating, dreaming, meditation, memory retrieval, information processing, and conscious perception, just like those associated with memory flashbacks.

“Through generating oscillations involved in memory retrieval, the brain may be playing a last recall of important life events just before we die, similar to the ones reported in near-death experiences,” Dr Zemmar speculated. “These findings challenge our understanding of when exactly life ends and generate important subsequent questions, such as those related to the timing of organ donation.”

Though this is the first study to ever measure live brain activity during the process of dying in humans, similar changes in gamma oscillations have been previously recorded in rats kept in controlled environments. This raises the possibility that, during death, the brain organises and executes a biological response that could be conserved across species.

The interepretation of this however is complicated by the fact that these measurements are based on a single case and stem from the brain of a patient who had suffered injury, seizures and swelling. Nonetheless, Dr Zemmar plans to investigate more cases and sees these results as a source of hope.

“As a neurosurgeon, I deal with loss at times. It is indescribably difficult to deliver the news of death to distraught family members,” he said.

“Something we may learn from this research is: although our loved ones have their eyes closed and are ready to leave us to rest, their brains may be replaying some of the nicest moments they experienced in their lives.”

Source: Frontiers