Re: Is there recent scientific information on brain activity and death?

Patrick:

Welcome to the wonderful world of the limits of measurement.

First, many stories are not true. The classic is that someone "wakes up" after 10-odd years in a coma to start a new career and date Meg Ryan.

In reality, it does not happen. Those that wake up were never in a coma. I refer you to one of my previous answers for a discussion on what coma actually is to avoid repetition.

Right, the media unwittingly, and not so unwittingly, distorts stories. Remember the story that we had cured cancer about three years ago?

What is "brain activity" that we "measure." Frankly, the best and most reliable method is the clinical exam--what you see is what you get. An electroencephalogram [EEG--Ed.] measures summations of potential differences registered from the scalp. What does that mean? Good question! It does not measure "activity" at all--though the "active" brain has known patterns. The reason I stress this is because the popular conception is that EEGs measure thought or that a "flat-line" EEG means brain death.

One can depress the activity of neurons--overdose on some barbiturates. In this way, one can depress the EEG. The person is not dead--provided you take care of some minor functions for him like breathing--and will return once the depressant gets metabolized. This is similar to any global assault to the brain.

EEG serves best to rule out a condition such as a seizure. A seizing brain does not function. A "subclinical" seizure in which you have an unresponsive patient with no overt sign of a seizure--convulsions, twitching, et cetera can be revealed by an EEG.

Now for what will seem like a tangent of sorts . . . EEG had become linked to brain death. Brain death involves the irreversible loss of function of the cerebrum and brain stem. An EEG that shows waves argues against a dead brain, and clinicians used this for that purpose. Does a "flat" EEG prove brain death? No. Again, Hollywood leads us to suspect it: "He has gone flat-line!"

EEG suffers from a lot of artifacts. Cases exist of "active" EEGs obtained from dead--necrotic on autopsy--patients. Indeed, monitors in the room can play havoc. Furthermore, if we depress your metabolism, shut your brain down, we do the same to your EEG.

Back to your story, this assumes it happened and that someone obtained an EEG. Now, a dead brain not only has no "activity" it does not have a near-death experience. People placed in a clinical coma and woken later do not have a "near death" experience during the coma. They do not remember the period.

"Near-death" experiences appear to result from a stressed brain--such as anoxia [Lack of oxygen--Ed.] in a cardia arrest. Clincally, the person fails rapidly and during probably the recovery, the stressed brain essentially makes things up. It cannot process stimuli properly.

How do we know this? We can recreate the conditions. The brain will make up things to fill gaps--confabulate in a sense. A person coming out of a stress will confabulate--and the events seem very real. "But wait, the guy said he was floating above the stretcher and heard exactly what the doctors, nurses, priests, and undertakers were saying!" Well, have you ever had a third person dream? You watch yourself? The brain can do that. Also, as you "come to" you process information not at all well. You can remember some parts, not others, and, frankly, make up details. The popular stories of "near death"--like "alien abductions"--provide you a frame work on which to attach events to create the story. Finally, just as a dream can distort the period of time you think has passed, the same can occur in the "near death" experience.

References? You want references? Not a lot of work has been done in the "main-stream"--how do you perform studies? College undergrads are gullible, but eventually word gets around. Also, doctors and researchers who are religious and want or expect an afterlife tend to find evidence for it, just as if you assume a person is guilty of a crime, you tend to underscore the evidence supporting it and dismiss contrary evidence. Negative studies do not spark much interests, especially for an ill-defined rare entity. Add in the little problem that a "negative" implies, to some, no existence of an afterlife, and you open a religious debate many wish to deny and avoid.

Now, to "cut to the chase" where is the evidence for this? I refer you to some articles in two journals--The Skeptical Inquirer and The Skeptic. The editor of the second has a few books, one of which describes how he unwittingly recreated the events similar to a "near-death" and an "alien abduction" on a grueling cross COUNTRY bike race. Check out the pages: www.csicop.org and www.skeptic.com.

Doctor X