Thursday, April 07, 2016

Evidence vs: plausibility in manual therapy

About "evidence-based" vs: "plausibility-based" - here's the thing. At least, here's the thing the way I see it.
You cannot prove any specificity with manual therapy. None that I know of, anyway. By that I mean, you cannot prove any cause-effect relationship. You can't prove that when you do x, y always happens. Sometimes y happens, and sometimes z happens. Sometimes nothing happens. The point is, you will never EVER 'know' what's going to happen. It's a crap shoot. N will always equal 1.
Take stroke following neck manipulation. That's pretty specific, right? Seems to happen a lot, right? An ER nurse I talked to once said that in her ER alone, she saw at least three per year, strokes following neck manipulation, by chiro. But let's not stroke out the chiros by talking about stroke *from* chiro, even though nearly 100% of the reports of death and maiming are about chiro neck manip. In fact that's the only time chiros seem to want to dissociate themselves from manip, instead of conflating themselves with it .. but I digress.
A manipulation event occurs, followed shortly thereafter by stroke. You would think it would only take one or two of these before the law would catch on and declare neck manipulation a kind of assault and battery. Especially since it leaves the patient mad and angry and feeling betrayed, and often litigious.
But no, neck manipulation is still allowed, probably because it cannot be "proven" to be causal! (see Roger Kerry's paper, Cervical spine pre-treatment screening for arterial dysfunction: out with the old, in with the new -  which lists a bunch of red flags for neck manipulation. Also see Harriet Hall's latest on the topic of no evidence, Chiropractic and Stroke: No Evidence for Causation But Still Reason for Concern.

We get nowhere in manual therapy, trying to find "evidence."
In fact, the DNM group page on Facebook was started by the researcher I was working with, years ago. She left the group after the study went down in flames. I remember her explaining about P values, confidence intervals, trend lines... talk that still gives me a dull headache. See the link Keith Eric Grant provided re: P values and how slippery it all seems to be,  Scientific method: Statistical errors.

In the end we had to toss the study because the subjects had backfilled their data books - one thing statistical analysis was good for - picking up on patterns that looked too perfect!
I don't want to sound negative about science - I love science. In the broad sense, I mean. A wide-angle view on the world, reality-based. And who knows? Maybe some day somebody will figure out the right question to ask, and put the right frame around it, and be capable of demonstrating some sort of direct causal connection between human primate social grooming and pain relief.
But I will not hold my breath waiting for that to happen:
If you can't "prove" that manual therapy (the stupid kind) is specifically causal for maiming and killing by stroke, I will bet the farm that you will never be able to "prove" that your light, slow, kind, interactive, responsive and *intelligent* ways of working at the surface of the body are specifically causal for pain relief.
It will always boil down to "non-specific effects." I.e., the patient's brain hacked its own self (in some smart, specifically unrepeatable, non-lethal way!) and changed its opinion about the state of its body, because, context.
So, that is why I prefer to think of a dermoneuromodulating approach as being plausibility-based instead of evidence-based.
We are already where we want to be, which is as far as we can get anyway, if we go with plausibility instead.
So, when you treat around the head and neck, please don't press hard on ANYthing there. And no jerking, K?
Set a favourable context, embrace uncertainty, let your fingers and hands be receptive, not blunt weapons, do no harm, and hope for the best.

Michael Leunig's brilliant cartoon.
It sums up the reality of the non-clarity of manual therapy.

Saturday, April 02, 2016

Pain does not equal nociception

Reading about pain can be very confusing. Why? Because those who are writing unconsciously or deliberately, from a biomedical standpoint, continue to conflate nociception and pain.
Once you learn the difference it is not so bad. Your brain will grow an automatic translation program that kicks in all by itself.

Here is the one I use:

1. Pain is a perception, perceived as a sensation.
2. The nervous system is separable, for mental exercise sake, into "central" and "peripheral"
3. Spinal cord is "central" nervous system, as is brain.
4. Once a signal reaches the first synapse in the dorsal horn, bam! it has reached the central nervous system.
5. Up to then, a noxious signal is merely nociception.
6. After that, if it makes it past that first hurdle, up to the thalamus and beyond, it may contribute to a pain experience.
7. Note that I said may contribute, which leaves space for a lot of other processing and inhibition before something else, called "pain," might be even potentially experienced.
8. Pain is multifactorial. Which means, experiencing it depends on a large number of factors.

It is good to know something about general features of sensory systems, the difference between tonic and phasic firing, and the difference between temporal and spatial summation, the difference between interoception (which, as far as I am concerned, includes proprioception) and exteroception. It's also good to know about the skin organ and where neurons came from. But none of those is what this blog post is about.