Friday, July 24, 2009

Cognitive Dissonance

Recent discussions on the alternative veterinary medicine e-mail list and on Pet Connection have made me think more about Cognitive Dissonance and the other ways humans can deceive themselves. Prometheus at Photon in the Darkness coincidentally has an excellent post up about cognitive dissonance today.

Unfortunately, Narda Robinson seems to be an excellent example of cognitive dissonance as well. For those of you who are not familiar with Dr. Robinson, she is the Director of Colorado State University's Center for Integrative Pain Medicine. While she seems to be very skeptical and science based in her analysis of many alternative modalities such as homeopathy, herbal medicine, and others, she often credulously endorses Reiki and possibly therapeutic touch, and teaches a $4,400 dollar course in acupuncture at CSU. She has studied the "neuroanatomical" approach to acupucture for many years. There is no doubt that sticking needles into living bodies causes a reaction in the nervous system. This reaction seems to include an effect on nerve transmission and can cause the release of endorphins in the central nervous system. The question is, does this have any significant clinical effect? Increasingly, the answer seems to be no.
Detailed and well-referenced discussions of the scientific evidence for the efficacy of acupunture are available here, and here. The acupucture archive at Science-Based Medicine is well worth a look as well. In short, the development of sham acupucnture procedures such as placing needles in random points, the use of fake needles that do not puncture the skin but appear to and tricking patients into thinking they are being needled by using things like toothpicks to create an illusion of being needled all seem to be as effective as "real" acupucture. This would indicate that the act of inserting needles has a potent psycological effect that can induce a placebo efect in humans, and possibly animals as well. (My previous post discussing the placebo effect in animals and their owners shows how thismight happen.) People often like to do something, indeed anything to help alleviate their animal's suffering. Unforunately, using an inefective or minimally effective treatment may convince the owner and veterinarian that they are helping, but the animal may still be suffering.
This is my foremost concern with the promotion of veterinary acupuncture. It is quite common for the proponents of veterinary acupuncture to claim that acupucture can reduce the need for anesthetic drugs, or help with postoperative pain and chronic pain. This may result in the use of inadequate doses of other, effective analgesic drugs and techniques. Veterinary pain relief has come a long way in the past few decades, and acupuncture to me seems to be a step backward rather than an improvement.
The reason I think that Dr. Robinson is an excellent example of cognitive dissonance is because she tries to force unscientific isdeas into her inconsistent idea of what the evidence shows. A true scientist and skeptic will put all their ideas, no matter how treasured, to the test of the evidence. While acupuncture is more plausible than homeopathy, the results of the best trials do not show much effect. Dr. Robinson and CSU are making a lot of money from their courses in acupucture and from treating pets with acupucture and other therapies with weak evidence. It is their responsibility to produce good evidence or effectiveness or to stop deluding themselves and others.

Orac's Friday dose of woo.

Orac has his Friday dose of woo up and it is about veterinary medicine this week. A good example of woo, which unfortunately is all too often practiced by licensed veterinarians due to the nature of veterinary practice acts in the US and UK at least.

Monday, July 20, 2009

"Not testable by science"

It is very common for practitioners of many "alternative" healing modalities to claim that the energy, vibrations, or "auras" they manipulate cannot be detected by modern science. Statements like this show a depressingly weak understanding of what we already know and what we are capable of measuring. The electromagnetic spectrum has been well known for over a century, and there are not any gaps in our understanding of it (there is no room for new unknown wavelengths or particles in the range of energy that exists in living bodies). We know in great detail how nerves, muscles and other tissues create and utilize energy, both chemical and electric and are continuously learning more details, none of which suggest any new, unknown mysterious force.
Our ability to measure incredibly small amounts of electromagnetic energy has also improved past the point that the discovery of some new unknown energy or vibration having a physiologic effect is vanishingly small. We can detect light and other wavelengths that have traveled for billions of years across the universe. We can also detect the light emitted by chemical reactions in human bodies. To get these types of images requires cameras that can detect light one photon at a time. Very weak signals in all other wavelengths (radio through gamma) can also be detected.
This understanding of the electromagnetic spectrum combined with extremely sensitive detectors makes the likelihood of discovering some new type of energy affecting bodies vanishingly small. Claims by CAM practitioners that science cannot measure what they do reflect either a profound ignorance on their part or a criminal disdain for the intellect of their customers.
An interesting exercise when confronting quacks is to ask how whatever they do works. If you get vague answers, keep asking questions. Often you will find that their ultimate answer is that it cannot be measured by science. This is a strong indication that their claims are unsupported by the evidence, and are not worth risking your money or your health (or your animals health).

Monday, July 13, 2009

The problem of Prior Probability, or why controlled trials of improbable propositions are a waste of time and money.

A common criticism aimed by supporters of alternative medicine modalities at those who are skeptical is that we are closed-minded and intolerant. "It can't hurt to study homeopathy, acupuncture, etc. We might find out that it actually works!" There are many studies that show that many types of CAM are at least mildly effective, but I would like to suggest that there are good reasons why a mild effect might show up in research, and why skeptics do not accept these types of results.

Some of the reasons a treatment may seem to work include the placebo effect as discussed previously, selection and observation bias, and unfortunately outright deception (this can be unintentional). This can result in studies being published that appear to show an effect. Often negative studies are not published at all (publication bias) as researchers and institutions often do not like to publish negative studies. Since the evidence-based medicine movement considers controlled trials the gold standard, reviews of CAM research can show potential mild effects or a need for further research that do not really exist. The prior probability of the modality may not be considered at all.

What is prior probability? It is simply defined as the scientific basis for something. CAM modalities such as Homeopathy, Reiki, Therapeutic Touch and other forms of "energy medicine" have extremely low prior probabilities because they either defy all known principles of physics, chemistry and biology (homeopathy) or are based on "energies" which no one can measure or demonstrate the existence of. Other types of CAM such as herbal medicine may have higher prior probabilities because they actually contain measurable amounts of chemicals that may or may not have an effect. This concept of prior probability is why skeptics say that extraordinary claims require extraoridnary evidence. An idea of how this applies can be gained from an understanding of Bayes theorem, which uses prior probability to evaluate the likelihood that a hypothesis may be true. Bayes theorem can be used in place of p-values (which can be misleading because they may not have a sound theoretical foundation). Kimball Atwood gave an excellent overview of these ideas at the Science-Based Medicine conferece jsut before TAM7 last week. His bibliography is here. This bibliography contains much more detailed discussions of these concepts than I have presented here.

A good understanding of basic statistics and of Bayes Theorem demonstrates why extraordinary evidence is required to prov extraordinary claims. When the plausibility and/or probability of a claim is exceedingly low, weak evidence is not sufficient to prove that it is true or even suficcient to justify spending further resources researching it.

Saturday, July 4, 2009

The Placebo Effect in Animals, and Their Owners.

A common reason people give as "proof" that various questionable therapies work is that "animals do not get placebo effects, because they don't know they are supposed to feel better".
This seems to make sense-animals do not "know" that a given treatment is supposed to do something, and I have been known to say this myself in years past. However, there are several reasons why this view may not be accurate.
One reason is conditioned responses, otherwise known as a Pavlovian response. Animals learn to respond in certain ways to actions or treatments. This response becomes automatic or subconscious. Humans are susceptible to conditioned responses just as animals are, and a conditioned response may affect our expectations or the way we perceive a given situation.
It does take time for a conditioned response to develop, but it may happen fairly quickly, sometimes over the course of a few treatments. When combined with effective treatments, regression to the mean and/or the normal healing process, the effect can seem dramatic. We (both owners and veterinarians) have a tendency to think that what we are doing is helpful because we want it to be helpful. This is a normal part of human nature, and is why randomized, blinded and controlled trials have been devised to help eliminate sources of error and bias, and why such trials are considered stronger, more reliable evidence than case reports, anecdotes, and unblinded, uncontrolled trials.
Another thing that has been demonstrated to affect both animals and humans is expectation.
It is not unusual for dogs to be more active and lively even after a simple, quick treatment like a vaccination. The dog has learned that a trip to the vet involves a brief, mildly unpleasant episode, then often a treat or car ride that the dog enjoys. The same expectation on the human owner's or veterinarian's part of improvement can also affect the way we perceive how a treatment is working.
What is the evidence that this expectation on the part of a caregiver can create a "placebo effect" in the caregiver as well as the patient? There have not really been any studies done in the veterinary field, but a some studies of preconceptions held by parents demonstrate how such an expectation may affect how caregivers can be affected by treatments. This report discusses how the common perception that sugar or other foods cause hyperactivity in young children is unfounded, and a recent review shows how parents, teachers and medical personnel can be effected by knowledge and expectation of treatment. I have seen several clients give their pets rescue remedy, a bach flower remedy which is a type of homeopathic remedy to their pets to help with anxiety just before a visit. I have always thought that the remedy seemed to calm the owner down more than the pet, and these reports help to explain why that may be.
A reasonable understanding of these effects on caregivers should instill some humility in any caregiver, and a critical analysis of how effective any treatment is. Unfortunately, such humility and critical analysis seems to be nearly entirely absent in many practitioners of alternative treatments and often in conventional practitioners as well. The difference between the effective treatments that have been developed over the last century or so and ineffective alternatives is testing and analysis by the scientific method. If someone claims that a treatment is not testable by science, or that science cannot detect the effect, that should be a red flag that the claim that the treatment works is bogus.