Fatigue measurement scales

Yes, me too – it does have a medical meaning that's a bit different, but all the same it's not quite right. Still think the most accurate definition I can draw from my own experience is an absence of energy, distinguishing it both from the normal sensation of tiredness, and from the psychological state of ennui.

 

Yeah I know. It's still more accurate but it's already been corrupted to a psychosocial thing so not an improvement. So technically they mean the same thing. But they don't. And they mean many other things. And many other words mean the same thing.

What an incredible mess, there is no other profession that fails so miserably on basic vocabulary. The infamous crash of a mars lander because of a mismatch between metric and imperial units is so much less egregious than this and it's still commonly used as an example of technical failure. But measurement units are clear and unambiguous so it's easy to communicate.

 

The huge problem with subjective sensations such as fatigue, is that without biomarker backup, it is incredibly difficult to differentiate between someone experiencing the sensation of utter fatigue, signalling to them they have no more useful energy left when in fact they do, versus someone experiencing the same sensation because they really don't have any useful energy left. The BPS crew always presume the former no matter what, because I suspect the latter is outside their ability or willingness to comprehend. They seem to lack the most fundamental requisite - common sense.

I find it horrifying that so many people in so many different roles in society, who hold the lives of so many others in their power, lack this most basic aptitude.

 

Basically highlights the whole problem. Fatigue, in all its forms, is so universally experienced, yet so immensely nebulous and hard to pin down when attempting to classify - let alone quantify - it. True of many subjective experiences I think.

 

I think the key here is that it's not measuring fatigue itself, it's measuring the impact of fatigue.

To my mind, what this MS Fatigue Impact scale highlights yet again is how differently we are being treated to people with diseases like MS.

There isn't all that much wrong with any of the questions if you start with the assumption of a 'real' underlying physical illness, and that people can be trusted to accurately assess and report the impact that illness has on them.

In that context questions like "I have been less motivated to participate in social activities" make sense. If you feel wiped out by your MS you'll naturally be less inclined to socialise. Easy to understand and empathise with.

If, on the other hand, you have ME and answer in the strongly affirmative, you'll have your doctor's choice of depression or (social) anxiety.

Same for statements like "I have had to pace myself in my physical activities", totally accepted if you have MS but viewed as a false belief if you have ME.

 

The key is to use a different approach in development, the unique step being to prune the list of questions on the basis of FACE VALIDITY by patients.

Too often the questions are selected by researchers, not patients.

 

This.

 

In software development it is a rare luxury to design and develop something completely from scratch. I've done so quite a few times and it is highly rewarding, but it is far from the norm at least in my experience. Mostly you are developing features that are strongly dependent on legacy infrastructure, and are bound by having to amend and extend what is already there. Inevitably the feeling is always "If only I could rip all this up and start afresh, and not have to make do and mend". If you can start over, then you get the chance to avoid the pitfalls of the original, rather than be stuck with and trying to work around them.

We have the luxury here of starting afresh with a clean slate, unsullied by outdated and flawed prior "solutions". Need to clear our heads of what has gone before.

 

To me, fatigue kicks in when your energy/performance level starts to drop, and in the cognitive dissonance test that I was trying out, I guess really I was measuring cognitive fatigue – not the performance level, but an abnormal drop in energies very quickly. It is also a measure of the time it takes for that energy to return, but I have no idea how you would measure that, because in measuring it you would prolong it.

I wonder if a simple physical test could measure the same thing. This is complete random thinking, so be kind to an old man, but what if there was something, say, to squeeze a few times (something calibrated to be well within your own level – not demanding), and you had to squeeze it just a very few times, rest, then repeat. I think we would start to show a fade long before we were aware of it, and long before healthy people. Perhaps a use for the old Scalextric controllers.

I'm not sure that you can measure fatigue in a questionnaire, and I certainly don't like anything that asks you to rate it on an undefined scale. As I mentioned in the physical activity questionnaire thread, the FINE trial results showed the weirdest changes in ratings among several patients (one went from 33 then to zero, back to 33, where zero is better than when healthy in every respect!)

I dislike it intensely when questionnaires confuse motivation with fatigue.

 

Ah, the old man gets repetitive, and is reminded gently by Trish! How on earth is anyone going to measure me going senile when I am already this bad?

Mind, I wasn't proposing anything that needed strength. I was thinking something quite easy: even then I think we would fade before noticing it. You've tried the cognitive tests: they were short enough not to have any real payback. I wonder if a gentle repetitive grip test would show a pattern. Perhaps a very easy grip to be squeezed five times, then a cup of coffee, then five more.

 

Yes, I'm pretty sure that if you could reliably measure a pwME's energy availability in real time, and plot it on a graph, the shape of the graph would very possibly be a strongly indicative signature in its own right. And possibly not plotted against time, but maybe against energy output or something.

And yes, measurement instruments that affect what is being measured can be a significant issue that has to be accounted for.

 

That might be something very interesting to see plotted on a graph, and see if the profile is different to healthy people. Does the rate of decline fall more sharply? Maybe other characteristics?

 

https://www.s4me.info/threads/hand-...l-biomarker-for-me-cfs-2018-nacul-et-al.6612/

More forum threads on hand grip strength via tag search:

https://www.s4me.info/tags/hand-grip-strength/

 

Chalder Fatigue Questionnaire mentioned here:

Pust, G., Pöttgen, J., Randerath, J., Lau, S., Heesen, C., Gold, S. M., & Penner, I. K. (2019). In search of distinct MS-related fatigue subtypes: results from a multi-cohort analysis in 1.403 MS patients. Journal of neurology, 266(7), 1663–1673. https://doi.org/10.1007/s00415-019-09311-2

https://pubmed.ncbi.nlm.nih.gov/31004211/

Abstract

Fatigue is among the most disabling symptoms in patients with multiple sclerosis (PwMS). The common distinction between cognitive and motor fatigue is typically incorporated in self-rating instruments, such as the Chalder Fatigue Questionnaire (CFQ), the Fatigue Scale for Motor and Cognitive Functions (FSMC) or the Modified Fatigue Impact Scale (MFIS).

The present study investigated the factor structure of the CFQ, the FSMC and the MFIS utilizing exploratory (EFA) and confirmatory factor analysis (CFA) as well as exploratory structural equation modeling (ESEM). Data of 1.403 PwMS were analyzed, utilizing four samples.

The first sample (N = 605) was assessed online and split into two stratified halves to perform EFA, CFA, and ESEM on the CFQ and FSMC. The second sample (N = 293) was another online sample. It served to calculate CFA and ESEM on the CFQ and FSMC. The third sample was gathered in a clinical setting (N = 196) and analyzed by applying CFA and ESEM to the FSMC. The fourth sample (N = 309) was assessed in a clinical setting and allowed to run a CFA and ESEM on the MFIS.

Proposed factor structures of all questionnaires were largely confirmed in EFA. However, none of the calculated CFAs and ESEMs could verify the proposed factor structures of the three measures, even with oblique rotation techniques.

The findings might have implications for future research into the pathophysiological basis of MS-related fatigue and could affect the suitability of such measures as outcomes for treatment trials, presumably targeting specific sub-components of fatigue.

Haven't read yet and don't understand the abstract ATM so just leave it here in case it could be relevant.

Related forum threads see opening post.

 

A good Twitter thread from Putrino Labs, explaining how symptom measurement needs to improve for LC and ME/CFS. Gives fatigue as one example.