Cerebellar Excitability Regulates Physical Fatigue Perception, 2023, Casamento-Moran et al

[I think this is the right forum for this study but please move if it's in the wrong place]

Cerebellar Excitability Regulates Physical Fatigue Perception

https://www.jneurosci.org/content/43/17/3094

The Washington Post has an article discussing this study which is how I found it:
Rethinking fatigue: Feeling tired vs. being physically depleted

(gift link) https://wapo.st/3NGfh8v

This article has a quote from Brian Walitt:

 

Begs the question: Why didn’t the study just use a Hand Grip strength measurement?

That would have provided some physical evidence of a decline in ability for people experiencing PESE.

 

Merged thread

https://www.washingtonpost.com/wellness/2023/05/04/fatigue-tired-coping/

This article is also on the ME Association face book: https://www.facebook.com/meassociat...rHHyA7Hg6CVAPtCyhHKan91EqFEuQKBQn695TKMUeTFml

I've (hopefully will be forgiven) stolen their choice of quotes and intro to describe it:

The Washington Post: Rethinking fatigue: Feeling tired vs. being physically depleted.

"A study suggests that perception of fatigue differs from physical fatigue, and this difference could lead to better treatments.
Fatigue affects the health and quality of life for many people, but there are few effective treatments for it, experts say.

Now new research suggests that redefining fatigue, and understanding how a brain region known as the cerebellum processes fatigue, may hold clues for better treatment."

 

It's sad that something so obvious--that 'fatigue' is still undefined and not understood--is newsworthy as an observation from a research study. Even more so that the study is poorly designed to really add to understanding fatigue. Fatigue, in its various forms, is something everyone experiences, and it has a very significant effect on the economy, worker safety, and other parts of human civilization, yet there's no push to understand it. I think it's deserving of more research effort, but with proper goals, so that the funding isn't wasted on studies of mice on roller skates or whatever.

 

Could be one of those lucky accident scenarios that was all that was needed where someone ran an experiment that happened to as part of its data capture the obvious and blow out the 'fatigue as captured by subjective surveys with leading questions' as if it were some measure. They've a valid point, and its been plain as day so nice to see. But yes, the solution isn't another quick fix but chucking out the dodgy pretend stuff to show it isn't a thing is an important part in starting it

But I guess the fact it is was used at all, and then a surprise [to see it inversely correlated] says it all about the up-is-down culture that has been fed far and wide by some of these 'ideas' of BPS. I suspect the only reason they thought to ask what their perceived fatigue was is because those groups have made it 'the norm' as if it meant something. Turns out it often means the opposite.

I'm pretty sure the cognitive psychologists who work with e.g. air traffic control would never measure fatigue as the BPS do (and they have to in order to look at and recommend breaks and working times, as well as set-ups to know how much drain different scenarios have and how long the human brain can keep it up for etc because if someone isn't on the ball the results aren't just that worker being tired), so it has been around for 30yrs the methods they could be using to have measured it more objectively and check their 'concept' was 'real' if it added up/was.

I guess it just says what we all know which is those who are most genuinely fatigued get used to and stoical about the level they experience so inverse relationship possibly between the measures the BPS use and reality of what most people understand fatigue to actually be in layman's terms. ie that in itself is a pretty prime point to make and stops us feeling like we are howling at the moon when someone suggests 'thinking less tired' will make a disease disappear is demonstrated by using a load of leading questions asking people 'how tired are you thinking right now'

 

No, those are two different aspects or forms of 'fatigue'. You could be unable to walk a mile due to metabolic limits, but you could also be unable to do that task due to perceptual problems: your brain is convinced that you don't have the energy to do so. If a hypnotist convinces someone that they are fatigued, is their ATP really reduced by that?

From my own ME experiences, I've never felt that my 'fatigue' was due to inadequate ATP. Unless I had physically overexerted myself, my legs always felt capable of a 40 km bike ride, but I often didn't have the mental energy to make the effort. My ME 'fatigue' seems to be neurological rather than metabolic.

 

Our experiences are very different, opposite in fact. I have the mental energy to do things, but my body wont fulfil what is asked of it. My motivation writes checques my body cant cash.

 

Physical strength and stamina are not a function only of ATP; there's a complex set of systems involved. Think of a modern gasoline engine: it's got all sorts of sensors feeding computers that control how well an engine runs. A failure in a sensor or a computer or a communication line can cause poor engine performance, even if the engine and fuel and air and ignition components are all working properly. I can't recall any ME studies that show that ATP production is drastically reduced in patients experiencing reduced physical ability. If the cause was reduced ATP production, that should be reasonably easy to clinically prove. The lack of such evidence means that the cause is more likely to be neurological. Your brain's "muscle performance monitor" might be telling you that your muscles have reached their limits, but that could be caused by a single nerve or glial cell malfunctioning.

If a car was having ME-like symptoms, you could do a computer or sensor swap. Swapping out a brain, spinal cord and nerve fibres is just not feasible. Simulating nerve signals with electric pulses should be easy enough, and you can compare physical and metabolic factors between PWME and controls. If there's not much difference, then it's not the muscles or mitochondria causing the experienced physical limitations. To me it seems like a simple and cheap experiment that would decide whether there should be further funding for the metabolic hypotheses for ME.

 

Yes, but this thread is also making assumptions of the cause of the lack of physical ability. "No energy in the tank" implies that there's limited ATP production, which isn't proven. "Inability to exert one's self" is more open to different causes.

This reminded me of an automotive problem I was told about. A guy's truck simply wouldn't start. Nothing was wrong with the engine. The problem was a brake light not working. Someone must have programmed the computer to consider that a critical safety failure, and prevented the engine from operating. Maybe ME is mis-registering something in the body as a critical safety failure and is blocking muscle signals to "help the body recover", and is stuck in that state.