Relationship between Fatigue and Physical Activity in a Polish Cohort of Multiple Sclerosis Patients : Rzepka et al 2020

https://www.mdpi.com/1010-660X/56/12/726?type=check_update&version=2

 

Patients with lower physical activity and greater MS related disability have more fatigue because it is so hard for them to do anything. They expend a lot of effort doing things that are easy for a healthy person. Think climbing a flight of stairs with one hand and a plaster cast on your leg.

 

I find studies like this very frustrating because they have not actually measured fatigue or activity, yet that is what they are claiming they have done.

They have only measured perception of fatigue related symptoms and perception of physical activity. Both sets of measures are subject to a common bias and hence the correlations don't mean much. While the obvious suggestion is to use objective measures of physical activity and fatigue. This is also another case where qualitative research would give better results than using a bunch of questionnaires and pretending that it is high quality because you can perform statistics that provide the illusion of quantitative results.

 

Sometimes I wish we had a "fuck YES!" button in addition to a "like" button.

This is the very thing in pain research that drives me absolutely crazy.

 

Note the way they use word order here to convey their implicit assumption about direction of causation. That is, that lower physical activity leads to greater fatigue.

Its like saying that "those who visit the doctor more frequently have a greater risk of death". You would never put it that way, because it suggests that the doctor visits somehow increase the death risk - almost everyone would agree that the direction of causation is almost certainly the other way.

I'm so sick of seeing these kinds of sleight-of-hand tricks. Its time to call them out.

 

Above all, the thing that makes me question these people's relationship to reality, is this simple act of complete illogic: arguing that since fatigue is the most common feature of disease, then causality must be the other around, the extremely unlikely and extraordinary other way around, because the obvious explanation is literally too obvious. This is the core of the argument: X cannot be true because X is too common, even more so when it presents with those very same features.

Above all it's this blatant rejection of Occam's razor that makes it loud and clear that absolutely none of this is rational or serious. The very same people who will trot the "think horses" line are also the ones jumping to the idea that maybe the hoof beats are just a magical Foley artist (the people who make sounds in movies) that follow people around, or some other farcical reason that can't even be said to be far out left field, it comes straight, or curved, from an extra dimension made entirely of, I don't know, wheat fiber or whatever. Makes no difference, it's just so far beyond breaking the fourth wall.

It's a desperate obsession with seeking out the supernatural while huffing and puffing about doing the opposite. I will never stop marveling at this.