Spikes in EEG at time of death
Information on the Study
There have been reports of a study indicating that patients who are on the verge of passing away in a hospice had a spike in electrical activity in the brain. The researchers involved in this study, from the Department of Critical Care Medicine in George Washington University Medical Centre in the United States, had concluded that near death experiences may be a consequence of a spike of electrical activity. See article
According to a report prepared by the Telegraph (read article) newspaper’s science reporter Richard Alleyne: “Doctors believe that a burst of brain activity occurs just before death and this could account for vivid "spiritual" experiences reported by those who come back from the brink.
The researchers suggest this surge could be why some 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. “We think the near-death experiences could be caused by a surge of electrical energy released as the brain runs out of oxygen,” said Dr 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.
Dr Chawla believes 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, Dr 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.
Dr 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.
Debate Regarding the Conclusions of this Study
This study which had generated a lot of interest in the global media raises a number of interesting points for discussion, which prompted us to explore it in more detail with our readers.
One of the major challenges with the interpretations that have arisen from the study as regards “near death experiences” is that it is not at all clear whether anyone had indeed experienced a near death experience at all. In this research study there was no actual confirmation that any of these patients had any “experiences” of any kind during the time in which they were dying let alone having “near death experiences”. Subjects in this study were those who were dying and were of course not resuscitated back to life and therefore the researchers would not have been able to know whether they had experienced anything at all. Of course, the patients were not able to be interviewed because they were allowed to pass away peacefully.
Therefore, the conclusions drawn by the researchers are at best hugely speculative. Perhaps more importantly there are a myriad of reasons why people could have a spike of electrical activity in the brain at the end of life.
Possible interpretation of the spikes
There is usually a change in the movement of calcium or other electrically charged substances in and out of cells. Every day we have significant movement of such substances in and out of our brain cells and that is why our brain cells generate electrical activity. This process mediates all kinds of events that take place both from a physiological and cognitive perspective. Because of this, it is almost impossible to conclude that electrical activity (which would have been the result of a movement in such substances) had necessarily been related to any “experience”. It is in fact far more likely that the spike in electrical activity is an artifact that is occurring when a person is developing severe disorders in the brain due to a lack of blood flow. There is extensive literature on the effects of blood flow on brain cells and it is clear that this does lead to significant movements of calcium.
Brain chemistry and human experience
An important question that is also raised is: “Does identifying a chemical change in the brain necessarily have impact on the meaning or reality of any human experience whether it be a near death experience or otherwise?
All human experience is mediated by the brain and in particular brain cell activity and thus identifying a specific pattern of brain cell changes cannot determine the reality or otherwise of any experience. For example, we know that human love or empathy as well as other emotions, such as jealousy, are all mediated by chemical changes across certain parts of the brain, however identifying them doesn’t imply they are “real” or not. The reality or otherwise of any experience is determined socially and is not based upon a pattern of changes in brain cells. Therefore scientifically speaking it is also not possible to determine whether near death experiences are real or hallucinations simply by observing a pattern of brain cell activity (even though there is a perception by some that the identification of brain based processes in near death experiences (or other human experiences) would imply that these are not real but rather hallucinations).
In summary, although we find this study to be somewhat interesting and does generate a number of important questions, there is unfortunately no evidence that the spike of electrical activity that the authors noted had any correlation with any human experiences whether near death or otherwise.