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.
Charlene Werner is getting a lot of attention she probably did not anticipate or desire. She is the star of a YouTube video in which she explains the scientific basis of homeopathy. Before you watch it, make sure you are sitting down, relax, and brace yourself for an onslaught of profound scientific illiteracy combined with stunning arrogance. For those with more delicate constitutions I will give you the quick summary:
Einstein taught us that energy equals matter and light, but because matter can be condensed down to a very small space if you remove all the empty space between the elementary particles (I am paraphrasing to make her statements minimally coherent), we can mostly ignore matter. Therefore energy is light, and we are all made of energy – not matter (or at least so little matter, you can ignore it). Stephen Hawking then came up with string theory, which tells us that all matter (which we can ignore) is made of vibrating strings. Therefore we are made of vibrating energy. All diseases are therefore caused by unhealthy vibrational states, and all disease can be treated by returning the body to a previous healthy vibrational state. This can be done with homeopathy, which extracts the vibrational energy out of stuff and places it in a small pill that can be used at any time.
Got it? This is now my favorite example of meaningless pseudobabble from a CAM proponent. Also, I am not picking on some unrepresentative crank – this is as good as homeopathy gets. Werner may be more clumsy and fumbling than more eloquent homeopathy proponents, but when you strip it down, magical vibrations is what you get. But Werner does a fabulous job of exposing the gaping holes is homeopathic nonsense.
A recent study published in the journal Complementary Therapies in Medicine shows no benefit from copper or magnetic bracelets for symptomatic treatment of arthritis. While this is a relatively small study, it highlights the lack of evidence to support this billion dollar plus industry.
The study is a double-blind, controlled crossover study involving 45 subjects with osteroarthritis. Each subject wore one of four bracelets – copper, two types of magnetic bracelet, and one demagnetized, in random order each for 16 weeks. It showed no difference among the four groups.
This is only the second published controlled trial looking at copper bracelets for arthritis. The first is from 1976 and showed some benefit. Then there are no published studies (just reviews and comments) for the next 33 years, until this current study.
Dr. Jay Gordon is a pediatrician to a particular subculture of pseudoscientific celebrities, such as Jenny McCarthy. He lends his MD cred to this community. He also appears, in my opinion, to be a shameless self-promoter – one of those pop professionals (Dr. Oz, Dr. Phil) who has sold his soul for some easy celebrity.
Regardless of his motivations, he has been spouting arrogant nonsense about vaccines for years, essentially arguing that his clinical gut feeling and anecdotal experience trump the actual science. This is exactly the wrong approach to science-based medicine.
In a recent open letter on his website, he adds to the anti-vax chorus advising not to get the H1N1 (swine flu) vaccine. It’s almost as if this crowd wants to maximize the morbidity and suffering from this somewhat preventable disease. I know this is not literally true, but their ideologically motivated and confused actions will have the same effect.