The American Heart Association and the American Stroke Association recently published in the journal Stroke a thorough analysis of the evidence for an association between cervical manipulative therapy (CMT) and both vertebral artery dissection (VAD) and internal carotid artery dissection (ICAD). The full article is online: “Cervical Arterial Dissections and Association With Cervical Manipulative Therapy: A Statement for Healthcare Professionals From the American Heart Association/American Stroke Association.” For background, an arterial dissection is essentially a tear in the inner lining of the artery. This tear disrupts the normal flow of blood, and also causes platelets to gather at the site of injury. This can result in a blood clot at the site of the dissection. This blood clot can block flow through the artery, or it can break off and lodge downstream, blocking flow at that point. Dissections, therefore, can result in a stroke (a lack of blood flow to a portion of the brain causing damage). There are four arteries in the neck that bring blood from the heart to the brain, two carotid arteries in the front, and two vertebral arteries in the back. A dissection in one or more of these arteries is associated with 2% of all strokes, but with 8-25% of strokes in patients <45 years old. This is mostly because strokes associated with processes like atherosclerosis are much less common in the younger population. Arterial dissections are classified as either spontaneous or traumatic. Trauma can be either severe, such as whiplash injury from a car accident, or subtle, such as from yoga or simply turning one’s neck to look past the shoulder. (more…)
Archive for Neuroscience/Mental Health
Years of analyzing popular but dubious claims leads to the impression that just about all knowledge that filters down to the popular consciousness is essentially wrong, at least as a first approximation. This may sound cynical, but think about any area in which you have specialized knowledge and compare that to what the average person believes about that area. Now extrapolate that to every other area of specialized knowledge.
I may be skeptical, but I am not a nihilist. I do think the situation can be and is being improved by popularizing science and other areas of knowledge. Experts need to be directly involved in teaching the public about their area, and when they are, popular beliefs can be corrected.
One example is the myth that we only use 10% of our brain. This is still fairly popular, and was recently a central plot element to the blockbuster movie, Lucy. However, Google “10% brain” and you will find nothing but links to sites debunking this myth, at least in the first few pages.
The BBC recently reported that a Guinean singer, Alama Kante, sang through her surgery in order to protect her voice. The reporting is unfortunately typical in that it emphasizes the seemingly amazing aspects of the story without really trying to put them into proper context. Specifically, the story emphasizes that hypnosis was used during the surgery, since Kante could not be placed under general anesthesia and still be able to sing, reporting:
“The pain of such an operation is intolerable if you are fully awake. Only hypnosis enables you to stand it,” he was reported as saying by to French publication Le Figaro.
“She went into a trance listening to the words of the hypnotist. She went a long way away, to Africa. And she began to sing – it was amazing,” he said.
Reports of major surgery being performed using self-hypnosis or hypnosis instead of anesthesia crop up regularly, because of the obvious sensationalism of such stories. I reported a similar case from 2008, for example. At least in this case the news report gave the critical piece of information, often missing entirely from such reports:
The Guinean singer, who is based in France, was given just a local anaesthetic and hypnotised to help with the pain during the operation in Paris.
I am formally requesting that Cancer retract an article claiming that psychotherapy delays recurrence and extends survival time for breast cancer patients. Regardless of whether I succeed in getting a retraction, I hope I will prompt other efforts to retract such articles. My letter appears later in this post.
In seeking retraction, I cite the standards of the Committee on Publication Ethics (COPE) for retraction. Claims in the article are not borne out in simple analyses that were not provided in the article, but should have been. The authors instead took refuge in inappropriate multivariate analyses that have a high likelihood of being spurious and of capitalizing on chance.
The article exemplifies a much larger problem. Claims about innovative cancer treatments are often unsubstantiated, hyped, lacking in a plausible mechanism, or are simply voodoo science. We don’t have to go to dubious websites to find evidence of this. All we have to do is search the peer-reviewed literature with Google Scholar or PubMed. Try looking up therapeutic touch (TT).
I uncovered unsubstantiated claims and implausible mechanisms that persisted after peer review in another blog post about the respected, high journal-impact-factor (JIF = 18.03) Journal of Clinical Oncology. We obviously cannot depend on the peer review processes to filter out this misinformation. The Science-Based Medicine blog provides tools and cultivates skepticism not only in laypersons, but in professionals, including, hopefully, reviewers who seem to have deficiencies in both. However, we need to be alert to opportunities not just to educate, but to directly challenge and remove bad science from the literature. (more…)
There used to be a time when I dreaded Autism Awareness Month, which begins tomorrow. The reason was simple. Several years ago to perhaps as recently as three years ago, I could always count on a flurry of stories about autism towards the end of March and the beginning of April about autism. That in and of itself isn’t bad. Sometimes the stories were actually informative and useful. However, in variably there would be a flurry of truly aggravating stories in which the reporter, either through laziness, lack of ideas, or the desire to add some spice and controversy to his story, would cover the “vaccine angle.” Invariably, the reporter would either fall for the “false balance” fallacy, in which advocates of antivaccine pseudoscience like Barbara Loe Fisher, Jenny McCarthy, J. B. Handley, Dr. Jay Gordon, and others would be interviewed in the same story as though they expressed a viewpoint that was equally valid as that of real scientists like Paul Offit, representatives of the CDC, and the like. Even if the view that there is no good evidence that vaccines are associated with an increased risk of autism were forcefully expressed, the impression left behind would be that there was actually a scientific debate when there is not. Sometimes, antivaccine-sympathetic reporters would simply write antivaccine stories.
I could also count on the antivaccine movement to go out of its way to try to implicate vaccines as a cause of the “autism” epidemic, taking advantage of the increased media interest that exists every year around this time. Examples abound, such as five years ago when Generation Rescue issued its misinformation-laden “Fourteen Studies” website, to be followed by a propaganda tour by Jenny McCarthy and her then-boyfriend Jim Carrey visiting various media outlets to promote the antivaccine message.
Earlier this month, the typical media outlets were abuzz (“Childhood nightmares may point to looming health issues“) with the results of a newly published study linking early childhood nightmares and night terrors with future psychotic experiences. Expressing little in the way of skepticism, most reports simply regurgitated the University of Warwick press release. The research, published in the quite legitimate journal Sleep, is interesting but I’m not sure it tell us anything that we don’t already know. And it certainly doesn’t support any causal relationship between sleep disorders of any variety and “delusions, hallucinations, and thought interference”. But before we delve into the specifics of the paper, I believe a quick review of sleep, and sleep problems, in children is in order.
What is sleep?
To the outside observer, sleep appears as an altered level of consciousness where response to our environment and voluntary movements are noticeably decreased. But, with a certain degree of variability, the line between sleep and wakefulness is pretty thin. This distinguishes it from the increasing stimulation required to reverse other states of altered consciousness such as lethargy, obtundation, stupor and ultimately coma, which is not acutely reversible. I don’t plan on getting too technical, but there is obviously much more to sleep than that. Physiologically our metabolic demands drop a bit, and we enter a generalized anabolic or “growth” state during which a number of beneficial processes take place, predominantly, we think, involving the brain.
Sleep is a vital aspect of human life that has appears to have both physiological and psychological purpose, and is essentially universal in the animal kingdom. All you need to do is observe a cat for more than five minutes to see that we aren’t the only animal species that both needs and seemingly enjoys sleep. In fact, if you could talk to a nematode, it would likely go on for hours about how much it enjoys sleeping in on Sundays. Humans spend roughly a third of their lives asleep, but the percentage of each day devoted to sleep is significantly higher during infancy and early childhood.
We don’t know why the need to sleep became part of the blueprint for life so early on in our evolutionary history, and researchers certainly haven’t worked out all of the nuances of why humans and other animal species continue to be so dependent on it throughout the lifespan. It is likely that its purpose has broadened over time as species branched out into new environments. There are a number of leading hypotheses, however. And barring some amazing technological or medical advance, we appear to be stuck with sleep.
Depression affects approximately 10% of Americans. It can be fatal; I found estimates of suicide rates ranging from 2-15% of patients with major depression. When it doesn’t kill, it impairs functioning and can make life almost unbearably miserable. It is a frustrating condition because there is no lab test to diagnose it, no good explanation of its cause, and the treatments are far from ideal.
Jonathan Rottenberg is a psychologist and research scientist who began to study depression after his own recovery from a major depressive illness. He teaches psychology at the University of South Florida, where he is the director of the Mood and Emotion laboratory. He has launched the Come Out of the Dark campaign to start a better, richer national conversation about depression. In a new book The Depths: The Evolutionary Origins of the Depression Epidemic, he reviews insights from recent experiments and asks a number of difficult questions, such as why humans evolved to be subject to incapacitating depressions. He comes up with some startling hypotheses, including the idea that evolution favored depression because of its survival value and that depression is essentially a good thing. He offers his ideas as the basis of a paradigm shift. (more…)
The word “paradigm” is over misused and overused, diluting its utility. Thomas Kuhn coined the term in The Structure of Scientific Revolutions to refer to an overarching explanatory system in science. Scientists, according to Kuhn, work within a paradigm during periods of “normal science,” punctuated by occasional “paradigm shifts” when the old explanatory model no longer sufficed, and a radically new explanatory system was required. The term has since come into colloquial use to mean any scientific breakthrough, which marketers quickly overused to refer to just about any new product.
I am therefore cautious about using the term, but I think it is appropriate in this case. In medicine I would consider a new paradigm to be an entirely new approach to some forms of illness. Common treatment paradigms include nutrition, physical therapy, surgery, and pharmacology. A new paradigm is emerging in my field of neurology – directly affecting brain function through electromagnetic stimulation.
The brain is a chemical organ, with many receptors for specific neurotransmitters. This has allowed us to use a pharmacological approach in treating brain disorders – using drugs that are agonists (activators) or antagonists (blockers) of various neurotransmitter receptors, or that affect the production or inactivation of the neurotransmitters themselves. There are limits to this approach, however. First, neurotransmitters are not the only factor affecting brain function. The brain is also a biological organ like any other, and so all the normal physiological factors are in play. Further, there is only so much evolved specificity to the neurotransmitters and their receptors.
One of the goals of rigorous science is to disentangle various causes so we can establish exactly where the lines of cause and effect are. In medicine this allows us to then optimize the real causes (what aspect of treatments actually work) and eliminate anything unnecessary.
Eliminating the unnecessary is more than just about efficiency – every intervention in medicine has a potential risk, so this is also about risk reduction.
It often seems to me that the goal of “alternative” medicine is to blur the lines of cause and effect, to exploit non-specific effects in order to promote a useless but profitable ritual (acupuncture comes to mind).