A muscle tone measuring gadget

You can learn something new every day, if you’re trying — and I never stop trying. Amazingly, I can still be surprised by the discovery of seemingly obvious things I have somehow missed after almost thirty years of constant study.

Like “myotonometry” — a muscle-tone measuring technology that has been around since the late 1980s. Missed it!

I knew about elastography: imaging technology that shows tissue stiffness and elasticity.

And I knew about algometers: gadgets that measures sensitivity to pressure.

But I had never even heard of myotonometry: tapping soft tissue to measure its reaction with accelerometers, revealing its tone and stiffness. It was invented in the late 1980s, and it started to pop up a lot in research in the 2010s. And yet, until recently, my article about cramps, spasms, twitches and tremors said this:

And so the idea of “normal muscle tone” cannot be defined, or even objectively measured. There is no tensionometer.

But there is! I stand corrected.

Myotonometry is a “valid measure to discriminate normal from abnormal muscle tone.” For whatever it’s worth, apparently it measures what we think it does (valid), and it does so consistently (reliable, see McGowen).

But there are some “here be dragons” problems, even if we trust the citations given (which is hardly a given). Abnormal muscle tone is very diverse, and many kinds would probably be missed or misrepresented by myotonometry because they are too transient, localized, and/or highly sensitive to contextual factors. Myotonometry’s accuracy is also limited by layers of other tissues, especially fat. Like any tool, it has limitations.

And then there’s the so-what factor: what is it worth? Is it actually telling us anything clinically useful? I look forward to digging into it more … now that I know it exists. I have doubts, of course.

But yeah… there is indeed a “tensionometer”! It does seem a bit weird to miss something like that, but it’s just part of exploring any deep topic thoroughly—the deeper you go, the stranger it feels to find whatever you’ve missed. And I’m now well into that phase of my career. 😜