Thursday, March 16, 2006

Near Death Experiences: close to having actual proof.

Near Death Experiences and the Mystery of Consciousness
Dr. Sam Parnia
Although we have all heard a great deal about near death experiences in the past 25 years, much of this has been debate and controversy centred around whether they are hallucinations or a glimpse of an afterlife.
The true significance of these experiences may soon finally be revealed through scientific research. Recent medical studies in cardiac arrest patients have begun to shed light on this fascinating phenomenon and have indicated that the mind and consciousness may in fact be what remains of us after death. If proven, this will of course have huge implications for all humankind. In this article I will examine our understanding of NDE during cardiac arrest and their significance for the wider debate on the nature of consciousness.
If one examines the medical literature in the last two decades, the most common theories for the occurrence of NDEs have involved either a hallucination brought about by physiological changes during the dying process, or a psychological stress reaction to the perceived threat of death. For many years these two theories have formed the basis of possible scientific explanations.
Many brain mediators have been proposed to account for the experiences, although none has yet been shown to be responsible for the phenomenon. These include release of endorphins; the body’s own morphine-like substance, lack of brain oxygen, increased carbon dioxide, various drugs and in particular those that can cause hallucinations such as ketamine and temporal lobe seizures.
The argument in favour of a psychological explanation has been based largely on observations made from retrospective cases indicating that near death experiences may sometimes occur in those who were not yet physically close to death at the time of the experience - such as in those occurring just before an accident. In addition, other studies have indicated the possibility of some cultural differences between near death experiences.
The answer about the significance of NDE is beginning to come from studies carried out with patients who have had a cardiac arrest.
Cardiac arrest patients are a subgroup of people who come closest to death. In such a situation an individual initially develops two out of three criteria (the absence of spontaneous breathing and heartbeat) of clinical death. Shortly afterwards (within seconds) these are followed by the third, which occurs due to the loss of activity of the areas of the brain responsible for sustaining life (brainstem) and thought processes (cerebral cortex).
Brain monitoring using EEG in animals and humans has also demonstrated that the brain ceases to function at that time. During a cardiac arrest, the blood pressure drops almost immediately to unrecordable levels and at the same time, due to a lack of blood flow, the brain stops functioning as seen by flat brain waves (isoelectric line) on the monitor within around 10 seconds. This then remains the case throughout the time when the heart is given ‘electric shock’ therapy or when drugs such as adrenaline are given until the heartbeat is finally restored and the patient is resuscitated.
Due to the lack of brain function in these circumstances, therefore, one would not expect there to be any lucid, well-structured thought processes, with reasoning and memory formation, which are characteristic of NDEs.
Nevertheless, and contrary to what we would expect scientifically, studies have shown that ‘near death experiences’ do occur in such situations. This therefore raises a question of how such lucid and well-structured thought processes, together with such clear and vivid memories, occur in individuals who have little or no brain function. In other words, it would appear that the mind is seen to continue in a clinical setting in which there is little or no brain function. In particular, there have been reports of people being able to ’see’ details from the events that occurred during their cardiac arrest, such as their dentures being removed.

A study by our group examining 63 cardiac arrest survivors on the coronary care and emergency units of Southampton General Hospital, which was published in the medical journal ‘Resuscitation’ demonstrated that approximately 6-10% of people with cardiac arrest have NDEs and out of body experiences.
There was no evidence to support the role of drugs, oxygen or carbon dioxide (as measured from the blood) in causing the experiences. In another study just completed in Holland, 344 cardiac arrest survivors from 10 hospitals were interviewed over a 2-year period, and 41 or 12% reported a core NDE. Patients with NDEs were then followed up for a further 8 years following the event and reported less fear of death and a more spiritual outlook on life. This study by a cardiologist Dr Pim van Lommel, is due to be published in the prestigious medical journal The Lancet either at the end of this year or early next year.
The occurrence of NDEs in cardiac arrest further highlights the fact that we currently know very little about the relationship between the mind and the brain. It also raises the possibility that some of the current theories regarding mind/consciousness, spirituality and the brain may need to be re-examined.
In the scientific community it is generally thought that the mind is a product of brain cell (neuronal) activity. This is based upon a number of studies including those with a technique known as functional MRI which have shown that certain sets of brain cells (neurones) in various areas of the brain become metabolically (chemically) active in response to a particular thought or feeling. This has led to a common view that the particular area of the brain that has been observed to change metabolically equates with the production of a particular thought. However, when examined critically, this observation only implies the role of such cells as a mediator in expressing those thoughts and does not necessarily imply an origin to the thought itself.
What is not known and what is currently an issue causing great debate in the field of neuroscience is how brain cells (neurones) which like other cells in the body produce molecular products such as proteins can lead to the subjective experience of the mind and thought. Although the conventional scientific view is that the mind is the product of complex chemical processes in groups of brain cells (neural networks) there are others who disagree.
In a lecture at the Royal College of Physicians in London a few years ago, entitled "Brains and minds: a brief history of neuromythology" to my surprise, the lecturer; a well respected professor of medicine discussed the mind/brain topic and concluded that the belief held by some neuroscientists that some day the discovery of more complicated molecular pathways would lead to an understanding of the mind is more compatible with "neuromythology" than neuroscience.
In addition to the neural network theory other alternative views have also been put forward. Some scientists and most notably Stuart Hameroff, an anaesthesiologist in Arizona and Roger Penrose, a mathematician in the UK, have proposed that mind or consciousness may be produced by quantum processes in brain cells.
Another view proposed by David Chalmers, a philosopher in Arizona, contends that the mind may itself be a separate entity in its own right. This is similar to the discovery of electromagnetic phenomena in the 19th century which could not be explained in terms of previously known principles, and which consequently led scientists to introduce electromagnetic charge as a fundamental entity in itself.
In a series of lectures held at the University of Sorbonne in Paris, Bahram Elahi, a professor of paediatric surgery has also defined ‘consciousness’ or the ’soul’ as a separate entity, which is made of a subtle type of matter that remains as yet undiscovered. Hence, contrary to popular belief, he defines ’spirituality’ as a science in its own right with its own laws theorems and axioms.
The occurrence of NDE and out of body experiences in cardiac arrest would support the view that mind, ‘consciousness’ or the ’soul’ is a separate entity from the brain. However, large studies are now needed to test and verify this. The key point in any study rests on testing the validity of consciousness and an active mind at a time when the brain does not function and the criteria of death has been reached. This can be done using large-scale studies together with independent tests of the out of body phenomenon in cardiac arrests. If the results are positive, this will then settle this age-old philosophical debate.

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