Archive for September, 2008

Sep 30 2008

Scientific Consensus

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I often refer to the “consensus of scientific opinion” and was asked to elaborate on exactly what that is and, more importantly, how it is determined. From a practical point of view, how can the average citizen get a handle on what the scientific consensus is on any given topic? For some burning questions, like whether or not there is significant anthropogenic global warming, much of the debate centers around whether or not there is a consensus and what it means. For others, like should we invest in biofuel from corn, a consensus seems elusive.

The Role of Consensus

For anyone trying to take a scientific approach to knowledge about the world, we must rely heavily upon experts, or those who are more knowledgable than we are. There is no choice – there is simply too much specialized scientific knowledge for anyone to be an expert in everything, or even a significant portion of scientific disciplines.

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Sep 29 2008

A Behaviorial Marker for Autism

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Autism researchers at the Yale Child Study Center have published the results of their research looking at the behavior of 2 year old children with autism. Specifically, they used eye-tracking software to see where they were focusing their gaze when looking at someone who is talking with them.

Lead author Warren Jones, with Ami Klin and Katelin Carr, found that children with autism tend to look at the mouth of someone who is talking, while children without autism tend to look at the eyes.

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Sep 26 2008

McCain’s Ptosis

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This has gone around the science blogs already, but as a practicing neurologist I thought I should weigh in. Moving Meet seems to have started the rumor, and Neurotopia has also added to the speculation.  Some people have just noticed that presidential candidate John McCain has left ptosis – which is a slight drooping of his left eyelid. From this they speculate that he may have had a stroke, or worse a brain tumor.

Orac has already done a fine job of dissecting this claim, pointing out that there are many causes of ptosis, most of which are benign. The one correction I would make (which is not his fault as he lifted it from a reliable resource) is that forehead Botox (the location of treatments used for cosmetic purposes) does not cause eyelid ptosis. It may cause brow ptosis (drooping of the brow, which is not what McCain has) but not lid ptosis. Injections of the eyelids themselves for things like blepharospasm (involuntary blinking) can cause lid ptosis. It would take ridiculously poor technique to cause lid ptosis from a forehead injection.

First, I think it is very irresponsible for non-specialists to speculate in public about the significance of a physical finding they don’t understand. It seems that the purpose is to generate rumors disguised as speculation.

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Sep 25 2008

Calorie Restriction for Life Extension

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There is a fairly direct correlation between scientific medicine and life expectancy, both historically and geographically. This makes sense – as we get better at preventing and treating diseases people will live longer. But the ultimate “disease” is aging itself. As we get older, our cells age, their DNA is damaged and the repair mechanisms are less effective. In short, our cells wear out.

Some researchers have therefore focused their efforts on discovering what, exactly, is happening to our cells as they age and can these processes be stopped or reversed. The motto of these researchers is “death in an engineering problem.” It is not inevitable – it is simply a challenge. Researcher Aubrey de Grey has been one of the most visible proponents of so-called “rejuvenation research.”

I have watched this research with an open mind but skeptical eye. Theoretically there does not have to be anything inevitable about aging. It is just another physical process. There is not theoretically reason why it should not be possible to intervene in whatever processes constitute aging.

However, I think aging will be a much tougher nut to crack than the rejuvenation enthusiasts imagine. Once we pick the low-hanging fruit, we are likely to find that some effects of aging are very difficult to address. Further, once we start trying to fix some of the effects of aging, only then will we discover what the true implications of such interventions are. There may be a host of downstream effects that then have to be addressed.

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Sep 24 2008

Homeland Security “Reads Minds”

Published by under Skepticism

Well, that’s what the headline says, anyway. Headlines are often misleading. They are often written by headline writers, not the journalists who write the articles, and they are optimized to titillate and intrigue, not to accurately represent the content of the article.

Still, such gross misrepresentation is irritating.

The technology being discussed is an experimental airport scan that would read a a passenger’s body temperature, facial expressions, and other biological markers and infer from them stress level, which will then be used as a warning sign of terrorist intentions.

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Sep 23 2008

Bacteria Are Your Friend

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In the Robot series of science fiction books by Isaac Asimov, which take place in the far future, there are “Spacers”, who are those who live on colonies off earth. The Spacers live in a germ-free environment, since the planets that they colonized were initially sterile and access to those worlds includes the requirement of being treated to remove any bacteria or viruses. This created worlds free of infectious disease, but as a consequence the Spacers have impaired immune systems. Without the regular workout of fighting off germs, their immune systems are weak.

The Hygiene Hypothesis

Like many ideas Asimov cooked up, there is some legitimate science to this science-fiction. The modern industrialized world is obsessed with hygiene. There is undoubted benefit to this cleanliness (other than its putative divine propinquity) – crowding together in cities, airports, schools, and shopping malls creates a friendly playground for viruses and bacteria, and good hygiene is the best prevention against infection.

But perhaps we are heading toward having too much of a good thing. From watching TV commercials you would think that the goal of healthy living is to have a germ-free environment. Clean your hands regularly with anti-bacterial soap, wash all surfaces with germ-killing agents, keep your food vacuum packed, and don’t play in the dirt.

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Sep 22 2008

More On Near Death Experiences

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There has been a great deal of discussion about the planned study of near death experiences (NDEs) since I wrote about the study on Friday. I focused my attention primarily on the neurological and scientific issues, but other issues were raised with regard to this study.

GM Woerlee wrote an extensive piece on this topic focusing also on the medical aspects of what happens during cardiopulmonary resuscitation (CPR). His primary point is that CPR generates enough blood flow to the brain in order to explain the experiences that survivors report. He also emphasizes that this research into NDEs has been done enough to arrive at the reliable conclusion that it is the experience of an anoxic brain and tha this further research is unecessary.

This, of course, raises the question of the usefulness of this proposed study – to place signs near the ceilings in ERs and ICUs and then see if people with NDEs could read the signs, meaning they were actually outside their bodies and not just feeling as if they were. I agree with the argument that this is a questionable use of finite research funds. There are certainly more pressing medical questions with a greater probability of a practical outcome. Public interest and the ideology of individual researchers – not good medicine – is driving this research.

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Sep 19 2008

Studying Near Death Experiences

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Near death experiences (NDEs) have been a favorite topic for the paranormal crowd for some time. If one could prove that consciousness survives the physical death of the body that would go a long way to opening the door to a wide range of paranormal claims. NDEs often occur in the medical setting, and this is partly why a team of doctors from the UK and USA are planning a rigorous study of NDEs.

That NDEs occur is not controversial – many people report remembering experiences around the time of cardiac arrest from which they were revived. Typical experiences include a sense of floating outside of one’s body, even looking down upon oneself and the events going on. Some people report a bright light, and others report “passing over” and being greeted by deceased loved-ones. The experience is often peaceful or euphoric, which contrasts to the way people feel when they eventually wake up. Surviving a cardiac arrest takes its toll and is not a pleasant experience.

The question is not whether or not people have such experiences – the question is how to interpret them. Just as even the most rigorous skeptic does not question that people see UFOs, but rather what the UFOs likely are.

The burden of proof for anyone claiming that NDEs are evidence for the survival of the self beyond the physical function of the brain is to rule out other more prosaic explanations. This burden has not been met.

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Sep 18 2008

NIMH Calls Off Chelation Study for Autism

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The NIMH has abandoned its plans to perform a study of chelation therapy in autism. In my opinion, this was the right move. It also appears that the decision was influenced by widespread criticism from many quarters, including the science blogging community, that such a study would be unethical.

I wrote about the NIMH plans to study chelation in autism for Science-Based Medicine.  In that article I brought up the main points of criticism – that the risks of chelation therapy were not outweighed by the probability of it being effective for autism, an unfavorable risk vs benefit ratio means that studying it in a vulnerable population (autistic children) entails special ethical problems, and that the primary stated goal of the study – to counter anecdotal reports of the treatment’s utility – would not be accomplished. The anti-vaccine mercury militia is not a group persuaded by scientific evidence, and so performing a scientifically and ethically dubious study to satisfy them is a fool’s errand.

Apparently, the NIHM got the message.

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Sep 17 2008

What’s in a Dinosaur Name

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I have a fascination with naming conventions. It probably derives from my predilection for systems and organization. (This is a predilection I believe my younger daughter has inherited – she obsessively sorts and organizes everything, like lining up all her stuffed animals by size, just because.) I was enthralled, for example, by the whole hubbub over the categorization of Pluto. I do think this kind of thing matters – language reflects thought, and how we organize our taxonomy reflects how we think about how things relate to each other.

At the same time I detest “language Nazis” who pedantically obsess over minutiae of language that do not reflect underlying organization of thought. For example, someone took me to task once for saying “hieroglyphics” instead of “hieroglyphic writing,” simply because the latter is correct.  I pointed out that language is a living thing that changes with usage, and when a word or phrase can be shortened for convenience without any loss of information, meaning, or unambiguity – that’s a good thing. Let it happen. “Hieroglyphics” is a perfectly cromulent word. (Incidentally, he later conceded the point when he heard a world expert in “hieroglyphics” use that term.)

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