Last updated: Tue, Aug 13, 2024
Several authors have emphasized that the inadequate perception of bodily states, especially, muscle tension levels, might contribute to the maintenance of chronic pain problems....Patients with chronic pain were shown to be notoriously unable to correctly perceive muscle tension levels at not only the affected muscle but also at a muscle unrelated to the pain problem. On the other hand, they greatly overestimated physical symptoms related to the tension production tasks, rated the tasks as more aversive, and experienced more pain upon tensing their muscles. This inability to estimate the correct current muscle tension levels might contribute to the continued maintenance of high muscle tension levels after stressors have subsided. The high focus on bodily symptoms and their overestimation may contribute to the perception of pain even at low levels of stimulation.1
I think it's rather a stretch to say that chronic pain patients are "notoriously" unable to perceive muscle tension. It's certainly not something that people talk about at parties.
Actually, on its face this seems a very plausible idea. I hope that physical therapists know all about it, and I appreciate that the researchers have my best interests at heart. However, there are serious weaknesses in the viewpoint presented above. In terms of body mechanics this is a problem only to the extent that it affects one's coordination and timing.
The experimenters tested the ability of their subjects to tense a particular muscle to correlate with the height of a bar on a computer screen. If the subject performed this task well, he was deemed to have good perception of bodily states, and if he performed poorly, he was deemd to have poor perception. This experimental task isn't very close to the natural task that we all must perform in order to stand and move. In the natural task, the inputs are myriads of inputs from skin, joints, muscles, eyes, and the inner ear. In the natural task, the relevant ouput isn't an EMG reading from a single muscle, but a symphony of interrelated forces and motions unwinding over time. It may seem likely (or even obvious) that someone who has trouble with the experimental task may also have trouble using his body in a safe and healthy way, but seeming likely is not scientific evidence of anything. Many gaps must be filled to establish this as even probably connected to long-term body health.
When Dr. Flor states that the chronic pain patients "greatly overestimated physical symptoms," what is she saying? Inescapably, one thing that she is saying is that she is better placed to correctly estimate the subjects' physical symptoms than the subjects are themselves. We have seen already (see, for example, Chronic Pain Physiology) that chronic pain patients have different nervous systems than normal people do. Does Dr. Flor perhaps mean instead that the patients judged the physical symptoms to be greater than the normal patients did? If so, that is an important distinction to keep in mind. We'll look at other ramifications of the subjective symptom/observer problem as it relates to both pain research and pain treatment.
When Dr. Flor mentions "a muscle unrelated to the pain problem," what is she saying? It appears to me that she is probably making an assertion that pain in one part of the body should not affect another part. Just from the pain physiology that I've shared with you so far this is certainly not something to be assumed. Pain signals at times may originate in one spot, but the picture of the overall pain system is of a high degree of interconnectedness. There are well-established patterns of bleed-through, and inside the brain all pain, wherever it may originate, seems to be boiled down to global affect. It seems to me that there are strong echoes of pain specificity theory (see The Specificity Model) in this statement.
When I'm in pain I don't have “a muscle unrelated to the pain problem.” My whole being is involved.
The final sentence in the long quote above is, The high focus on bodily symptoms and their overestimation may contribute to the perception of pain even at low levels of stimulation.
Assuming that were all true, what then? Let's break it down. First, it should be no surprise that people who are in pain are aware of it, or that it should be important to them. Next we have "overestimation" again. One of the hazards surrounding pain research and pain treatment is that pain is no more and no less than a perception. It is what it is. The assertion that an individual is "overestimating" their perception can never be a scientific assertion. This problem comes up in dozens of forms in this field, and one of the points of this book is to look at these problems to see who they are a problem for and whether they are dealt with prudently. Finally, taking this sentence altogether, does it really say anything more than that chronic pain patients hurt more than it seems to someone else that they should? How does a statement like that help anyone, and why is it worth the paper and ink to print it on? Just askin'
I included this example to raise the point that interpretation of experimental results is hazardous, and there seems to be a bias toward exaggeration of both concepts and the weight of evidence. This idea will be followed up in several of the following chapters.