“Evolutionary Reasoning: It can transform your manual care” – Barrett Dorko

This is the first article to be posted on Physical Therapy Web by featured writer Barrett Dorko. It is entitled “Evolutionary Reasoning: It can transform your manual care.” Please leave your comments.

You can find an extensive collection of Barrett’s writing at The Clinician’s Manual.

I’m no expert on animal behavior but I’ve read a bit and I am, after all, a human animal and I own a dog. Though it’s been said that we are distinguished from the ape by our opposable thumbs, I’m not certain that this makes us more capable in every sense. Apes certainly seem far better at relaxing in the jungle. For this I personally need a large recliner. My thumbs don’t come into play here.

If I were to choose, I’d say that it was my ability to think before I act that makes me human. I have a sense of what instinct might do to drive my movement and thus inhibit that movement with the higher centers of my brain. It separates me from the Beagle (see Running With Buckeye for more on this).

As a clinician, teacher and writer I’ve found some wonderful material on reasoning in practice that I want to share here. I’ll do it briefly and provide some references. Things I write for you in the future or have written will reinforce all of this. I really hope this doesn’t just become a “because I’ve already said so” kind of thing. Feedback is more than welcomed.

Defense or Defect?

Louis Gifford states in An introduction to evolutionary reasoning: diets, discs, fevers and placebo (Topical Issues in Pain Volume 4) “Good reasoning when applied to the understanding of any presenting observation, or condition involves two perspectives: An evolutionary perspective asks the simple question “Why?” and a more traditionally scientific perspective asks the question “What?” or “How?” about structure and mechanisms. The ‘what and ‘how’ reasoning perspective is termed a proximal, or near explanation of cause for a given observation. In medicine, proximal explanations address how a body works. Evolutionary or ultimate explanations show why humans, in general, are susceptible to some diseases and not to others (See Nesse & Williams Why We Get Sick: The New Science of Darwinian Medicine Vintage 1994).”

Without a doubt, we need both the near and ultimate explanations in order to form a plan of treatment in our heads, but while the former is commonly used the latter seems absent in many of the clinics I’ve visited. To me, this is like an instinctive reaction overwhelming a thoughtful response.

Evolutionary or ultimate reasoning suggests we divide bodily response to trauma or disease into one of two categories – defects and defenses. Defects are those processes or behaviors that reveal the body’s weaknesses; they are the result of the disease process and are present without any particular utility. Defenses serve a purpose. They promote a change toward health and homeostasis. If we categorize our findings upon exam in this way, we are guided toward care that seeks to reduce the manifestation of the defect and leave the defense to do its job.

Here’s the example that I always use while teaching: If you sense or demonstrate a persistent isometric contraction in your patient, how might you interpret that?

If the origin of their complaint of pain is mechanical deformation (see The Origins of Pain), how do you interpret that finding? Well, it depends upon whether you reason proximally or ultimately. Using only the former you’ll assume this is an isolated problem, in fact, a defect at the level of the muscle itself and you’ll work to “relax” it. Seen from the ultimate perspective, this activity may easily be understood as a defense and thus you’ll work not to stop it, but enhance it. That is to say you’ll create a context that permits its fuller isotonic expression.

Wouldn’t that change everything?

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