May 21, 2021
Summer marks the seventeenth anniversary of my first evidence-based practice course. If you’re a Marquette graduate who took one of my first classes, let me apologize now. The early years were rough. The turning point did not come until I could answer two questions.
1) At the end of this course, what should students know?
2) What should they be able to do?
Once I figured that out, I became more effective. Every reading assignment, lecture, and project was designed to help students get to the endpoint. I stopped assigning entire chapters of the textbook, replaced Medline searches with PubMed, and began emphasizing statistical interpretation over computation. I increased the number of research articles students read, and I created appraisal guides that always asked why. “Yes, the sample size was small, but why does that threaten the believability of the authors’ conclusions?” But no matter how many times I’ve revised the course, one thing has never changed. I always spend a lot of time on theory.
A theory is our best attempt to explain a set of events, observations, or phenomena. Theories are testable, changeable, and used to make predictions. There is a terrific example of a scientific theory in Iain Pears’ historical novel, An Instance of the Fingerpost. One of the characters, a physician-scientist working in 15th century England, is discussing respiration when he asks,
“Why do we breathe? We assume it is to regulate the body heat, to draw in cool air and thus moderate the blood. Again, is that true? Although the tendency to breathe more often when we exercise indicates this, the converse is not true, for I placed a rat in a bucket of ice and stopped his nose, but it died nonetheless.”
The character theorizes that breathing moves air in and out of the body to cool the blood. Supporting evidence comes from the observation that, during exercise when our bodies heat up, we breathe heavily. He makes a prediction. A cold rat need not breathe. Unfortunately (especially for the rat), the character’s theory does not withstand his test. Immersed in ice with his nose plugged shut, the rat meets his demise. At this point, the reader can only hope that the character will modify his theory to account for recent events and spare other rats a similar fate.
It’s easy to laugh at the naiveté of Pears’ character, who does not yet appreciate that respiration permits the exchange of oxygen and carbon dioxide, which his vital to life regardless of temperature. But when we’re done chuckling, we’d be wise to appreciate that his question (i.e., What will happen if I plug the nose and cool the rat down?) is completely logical in light of his theory. We all hold theories, proven and unproven, that influence our actions. Here’s a few that might hit closer to home.
· Are you old enough to remember when we thought that spicy food caused stomach ulcers? I am. People suffering from ulcers were advised to change their diet. Today the prevailing theory is that ulcers are caused by bacterial infection, and antibiotics are a first line treatment.
· I also remember learning that slow-release narcotic medications were not addictive. We all know how that theory evolved.
· Are you a physical therapist? If so, you probably believe that a well-designed exercise prescription improves physical function and that better posture reduces neck pain. But have you ever worked with a patient for whom stretching, strengthening, and postural education does not work? Is the problem with the patient or your theory? If I thought my theory were flawed, I’d probably change course and try a different approach to care, maybe manual therapy. But if I thought the patient were the problem, I might nag her with, “Do your exercises!” Regardless, my theory drives my actions.
In a few days, 65 students will walk into my classroom. Each will come with their own theories. Some will be common to the group, like “PT is a worthy profession.” And, “I’ll probably do better in this course if I skip the beach and show up for class.” Others will be unique. One year I mentored a group who wanted to study whole body cryotherapy for people with rheumatoid arthritis. Their theory was that cold clears toxins from the body. In our initial discussion, I asked them to identify the toxin(s) that cold would clear (mercury, perhaps?) and to explain the relationship between toxins and rheumatoid arthritis. Afterall, if the theory predicts that clearing toxins will resolve symptoms, it follows that the condition is influenced by toxins. They flushed it out (their ideas, not the toxins), and their theory evolved.
I don’t know what this summer will bring. Theories about cupping? No, Olympic swimming hasn’t started yet. Interest in dry needling? Maybe. Motivational interviewing has come to the fore; maybe students will want to talk about that. Regardless, we’ll meet the learning objective from the syllabus stating that “students will be able to recognize, articulate, and evaluate theories underlying patient care decisions.” That’s the endpoint. And regardless of the topic, it’s important that we get there. Why? Carefully considered theories lead to better clinical decisions. That’s my theory, anyway.
Thanks for reading. If you like what we’re doing, you can support the work at https://www.buymeacoffee.com/ptworkshop. We would like to keep Shop Talk free and are actively seeking sponsorship. If you’d like to underwrite our work (or know someone who would), please contact The Evidence Workshop at [email protected]. Until next time, take care.
For those who want to learn more, check out the resources below.
· Here’s a link to Iain Pears’ books. https://www.penguinrandomhouse.com/authors/23472/iain-pears/
· Here’s some information on stomach ulcers. Scroll down to Cause to learn about bacterial and dietary factors. https://en.wikipedia.org/wiki/Peptic_ulcer_disease
· The FDA provides some information on whole body cryotherapy here. https://www.fda.gov/consumers/consumer-updates/whole-body-cryotherapy-wbc-cool-trend-lacks-evidence-poses-risks
· Information on rheumatoid arthritis, including complementary treatment, can be found on the Arthritis Foundation website. https://www.arthritis.org/health-wellness/detail?content=treatment
· The Summer Olympics are scheduled to begin in Tokyo on July 23rd. https://en.wikipedia.org/wiki/2020_Summer_Olympics
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