Another one bites the dust.
The National Center for Complementary and Alternative Medicine (NCCAM) is generally a waste of taxpayer money, but they have sponsored several well-designed large trials of popular herbal supplements. And one by one these studies have shown these popular products, such as echinacea for the common cold, to be ineffective.
To add to the list, published in JAMA this week are the results of the largest and longest trial to date of Gingko biloba for the improvement of cognitive function and to treat, prevent, or reduce the effects of Alzheimers disease or other dementia. The results of the study are completely negative.
The study was very rigorous – a consensus trial designed to address all the criticisms of prior smaller studies. It was a direct comparison of Gingko biloba at 120mg twice a day, double blind, randomized, multi-center trial involving 3019 subjects aged 72-96 for a median of 6.1 years. Subjects were followed with standardized tests of cognitive function.
Peter Lipson reported Monday about new research suggesting that Multiple Sclerosis may be caused by venous blockage. He correctly characterized some of the hype surrounding this story as “irrational exuberance.”
This is a phenomenon all too common in the media – taking the preliminary research of an individual or group (always presented as a maverick) and declaring it a “stunning breakthrough,” combined with the ubiquitous personal anecdote of someone “saved” by the new treatment.
The medical community, meanwhile, responds with appropriate caution and healthy skepticism. Looks interesting – let’s see some more research. There is a reason for such a response from experts – experience.
The primary reason that I and others favor science-based medicine, as opposed to the alternatives, is that science works. As Carl Sagan said, “Science delivers the good.” Science has other virtues – it is transparent and self-corrective also.
Recently two unrelated news items have provided an opportunity to compare a scientific vs a pseudoscientific approach to the same problem – that of communicating to patients who are locked-in.
Locked-in describes those who suffer from an injury or neurological disease that mostly paralyzes them, so that they cannot move or communicate. One scenario that leads to a locked-in state is a brainstem stroke, where patients are paralyzed below the eyes – they can only blink and move their eyes, but nothing else. Widespread trauma can lead to a similar situation. ALS, which leads to progressive loss of motor neurons, can also result in total or near total paralysis.
Several weeks ago I wrote the first in a brief series of posts discussing the different types of evidence used in medicine. In that post I discussed the role of correlation in determining cause and effect.
In this post I will discuss the basic features of an experimental study, which can sere as a check-list in evaluating the quality of a clinical trial.
Medical studies can be divided into two main categories – pre-clinical or basic science studies, and clinical studies. Basic science studies involve looking at how parts of the biological system work and how they can be manipulated. They typically involve so-called in vitro studies (literally in glass) – using test tubes, petri dishes, genetic sequencers, etc. Or they can involve animal studies.
Clinical trials involve people. They are further divided into two main categories – observational studies and experimental studies. I will be discussing experimental studies in this post – studies in which an intervention is done to study subjects. Observational studies, on the other hand, look at what is happening or what has happened in the world, but does not involve any intervention.
Many parents of children with autism have expressed to me their dismay that the anti-vaccine lobby is sucking all the oxygen out of the room for autism awareness. They feel that just being a parent of a child with autism makes others assume that they are anti-vaccine. They also worry that resources and attention are being diverted from promising legitimate research because of all the attention being paid to the failed vaccine hypothesis.
So it is good to occasionally focus on mainstream autism research to show that progress is being made, despite the unfortunate anti-vaccine sideshow.
A recent study published in the latest issue of Pediatrics shows that early intervention in toddlers with autism can have significant benefits. The study is a randomized controlled trial of the Early Start Denver Model compared to conventional treatment in 18-30 month old children with a diagnosis of autism spectrum disorder (ASD). The study is a reasonable size for this kind of intervention – 48 children were randomized – and this is sufficiently powered to get statistical significance. But it should be noted this is still a smallish study and replication to confirm the results is welcome.
Another potential weakness is that the control group was “referral to community providers for intervention commonly available in the community.” Therefore the control group was not standardized and it’s possible this group was sub-optimally treated. Further, while the groups were randomized they were not blinded.
I don’t know. The mainstream media is doing a wonderful job sensationalizing this case, presenting it without skepticism. Some outlets are doing a good job of discussing the relevant issues – but they don’t have the information to have a meaningful discussion of this particular case. Details are tantalizing but thin.
The case is that of Rom Houben. The story was broke, as far as I can tell, by the Mail Online – yes, that is a huge red flag. It does not make the story wrong, it just doesn’t instill in me confidence in the reporting.
Mr. Houben was in a terrible motor vehicle accident 23 years ago and has been paralyzed ever since. His diagnosis has been PVS – persistent vegetative state. However, recently, we are told, his mother insisted on a neurological re-evaluation. This is actually quite reasonable, generally speaking (again, without knowing specific details of this case).
There are two general approaches to subverting science-based medicine (SBM): anti-science and pseudoscience. Anti-scientific approaches are any that seek to undermine science as the determinant of the standard of care, often overtly advocating for spiritual or subjectively-based standards. Some attack the validity of science itself, usually with post-modernist philosophy.
Pseudoscientific proponents, on the other hand, praise science, they just do it wrong. In reality there is a continuum along a spectrum from complete pseudoscience to pristine science, and no clear demarcation in the middle. Individual studies vary along this spectrum as well – there are different kinds of evidence, each with its own strengths and weaknesses, and there are no perfect studies. Further, when evaluating any question in medicine, the literature (the totality of all those individual studies) rarely points uniformly to a single answer.
These multiple overlapping continua of scientific quality create the potential to make just about any claim seem scientific simply by how the evidence is interpreted. Also, even a modest bias can lead to emphasizing certain pieces of evidence over others, leading to conclusions which seem scientific but are unreliable. Also, proponents can easily begin with a desired conclusion, and then back fill the evidence to suit their needs (rather than allowing the evidence to lead them to a conclusion).
In a special episode of the Skeptics’ Guide to the Universe podcast, I host a discussion with David Gorski, Mark Crislip, and Joe Albietz about the flu, the H1N1 “swine” flu pandemic, and the controversies surrounding the flu vaccine.
You can download or stream the episode here. You can also subscribe to the podcast via iTunes or other popular aggregators.
Homeopathy, as a cultural phenomenon, remains an enigma. In the two centuries since its invention it has failed to garner significant scientific support. In fact, developments in physics, chemistry, biology, and medicine have shown the underlying concepts of homeopathy to be wrong – guesswork and speculation that lept in the wrong direction.
It turns out, like does not cure like. This is nothing more than sympathetic magic – popular at the time but now considered nothing more than superstition without any scientific basis.
It also turns out that diluting a substance does not make it more potent – this nonsensical idea (ridiculed even in the 19th century) violates the laws of thermodynamics, and the chemical principle of mass action. This is especially true when you dilute a substance beyond the point where chance would have even a single molecule of active ingredient left behind. The background noise of chemicals in homeopathic water is orders of magnitude greater than the signal of whatever had previously been diluted in it.
I have never used those words to a patient or about a patient. I have also never heard a colleague use any similar term to a patient. And yet on many occasions I have had patients ask me, “So you’re telling me it’s all in my head?”
The concept of what are now called psychogenic symptoms is a tricky one for various reasons. There is an unfortunate stigma attached to the notion that our brains can cause physical symptoms. Making the diagnosis is complex. Outcomes are variable and are hampered by the difficulty in communicating the diagnosis to patients. Psychogenic symptoms often mask underlying physiological disease. And the risks of both false positives and false negatives are high.
This complexity leads some to argue, in essence, that psychogenic symptoms do not exist at all – that the diagnosis is a cop out, a way to blame the patient for the failings of the physician. But this approach, ironically, is a cop out, because it seeks to white wash what is a real and complex disorder with an overly simplistic and moralistic approach.