What the recording of a dying human brain could tell us

For the first time, doctors have collected detailed brain wave activity before and after a sudden death. In their interpretation, the researchers suggest life may indeed “flash before our eyes”—but other experts aren’t so convinced. 

Doctors in Estonia were monitoring the brain of a 87-year-old patient to detect and treat his newly developed epileptic seizures. During these readings, the patient suddenly had a heart attack and passed away. But that left the team with a unique new set of data: the first electroencephalogram (EEG) recordings of a dying human brain. The team looped in international collaborators to analyze the recordings of the patient’s brain 30 seconds before and after his heart stopped beating. They found that brain waves remain active and coordinated during and even after that transition into death. 

Two types of brain waves were most active: Gamma waves, which are especially associated with dreaming and memory retrieval; and alpha waves, which are associated with information processing and the visual cortex—the team speculates this could indicate “life flashing before your eyes” in the moments before death.

“It is intriguing to speculate that such activity could support a last ‘recall of life’ that may take place in the near-death state,” the researchers wrote in their paper, which was published in Frontiers in Aging Neuroscience on Tuesday.

The study authors say these data may show a dying brain retrieving and visualizing memories. “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,” Ajmal Zemmar, a University of Louisville neurosurgeon and the organizer of the study, said in a statement. “These findings challenge our understanding of when exactly life ends.”

While these findings are intriguing and unique, they far from prove any life-flashing phenomena. Each different type of brain wave is associated with a plethora of different cognitive functions—they’re more sweeping categories of brain activity than indicators of any specific thoughts.

Linking an increase in gamma brain waves with flashbacks before death is a stretch, Steve Taylor, a psychologist at Leeds Beckett University in England who wasn’t part of the research team, told The Guardian. He added that, “I don’t think we can assume this is a representative example of how the human brain behaves at the point of death.”

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It’s important to note that these observations occurred in a single patient, who had recently suffered injury. The 87-year-old patient entered into emergency care after a fall. He had concerning neurological symptoms as well as a midline shift due to bleeding in the brain—when the brain is pushed off-center due to uneven pressure in the skull. Combined with the effects of medications, the patient’s brain activity in his last moments may not even be representative of what could happen in others.

“Whether the recorded activity underlies any particular kind of subjective experience—whether so-called ‘near death experiences,’ or impressions of life flashing before one’s eyes—is impossible to say, and will likely remain so,” Anil Seth, a neuroscientist at the UK’s University of Sussex who was not involved in the research, told The Guardian. Though, he added, the data are “pretty unique,” especially because there is no ethical way to experimentally obtain readings like these. 

Similar changes in gamma waves have been previously observed in the brains of dying rats following heart attacks, suggesting a heightened consciousness in moments right before death. Zemmar plans to investigate more of these cases.