Fatigue and perceived fatigability, not objective fatigability, are prevalent in people with post-COVID-19, 2022 Fietsam et al

Abstract


Persistent symptoms after acute COVID-19 infection, termed post-COVID-19 fatigue, occur in 44–70% of patients. Characterizing fatigue in this population is vital to determine the etiology of post-COVID-19 fatigue symptoms and to assess the effectiveness of potential interventions.

The purpose of this study was to assess differences in perceived and objective fatigability between people with post-COVID-19 symptoms (N = 29, 20 females) and people who had COVID-19 but are not experiencing persistent symptoms (N = 20, 12 females).

Perceived fatigability, fatigue, pain, and quality of life were assessed with the Fatigue Severity Scale (FSS), Fatigue Assessment Scale (FAS), Visual Analog Scale for Pain (VAS), and the EQ-5D-5L, respectively.

Objective fatigability was evaluated with torque and work fatigue indices (FI-T and FI-W), calculated via an isokinetic fatigue task.

The results revealed that, the subjects with post-COVID-19 symptoms had significantly higher FAS (p < 0.01), FSS (p < 0.01), VAS (p < 0.01), and EQ-5D-5L VAS (p < 0.01) scores compared to subjects without post-COVID-19 symptoms, indicating greater fatigue and perceived fatigability, increased pain, and worse quality of life.

However, there were no differences between the two groups for the FI-Ts (all p ≥ 0.07) or FI-W (all p ≥ 0.08), indicating no differences in objective fatigability. This study found that people with post-COVID-19 symptoms have increased fatigue and perceived fatigability, but not objective fatigability, compared to subjects without post-COVID-19 symptoms.

paywalled (but graphs available at link)
https://link.springer.com/article/10.1007/s00221-022-06518-0

 

This is a good example of actual biological reductionism. On what basis has it been decided that this single test is a reliable objective measure of fatigability? Is fatigability even well-defined enough to be of use? When fatigue is clearly not? When PEM is involved, another concept that medicine simply refuses to even bother learning. On the basis of a single arbitrary test, reality has been decided to be one way or another about an entire group of people, whose main feature is a wildly fluctuating illness with many grades and severity levels.

This entire paradigm makes no sense at all. This is the opposite of comprehensive testing, so much effort to check one thing only, not even a relevant one, and what is even the point?

Given the name "isokinetic fatigue task" and the figures referencing an extensor, the test is probably something like this:

 

It spends some time exploring the idea that brain hypo-metabolism could be the cause of the perceived fatigue. It cites previous studies to support this, for example: "A review by Rudroff et al. (Rudroff et al. 2021) summarized studies in people with post-COVID-19 that showed FDG-PET hypo-metabolism in a variety of brain regions and associations with symptoms (Fleischer et al. 2022). For example, Guedj et al. (Guedj et al. 2021) found hypo-metabolism in the bilateral rectal/orbital gyrus (including the olfactory gyrus), hippocampus, temporal lobe (including the amygdala), bilateral pons/medulla brainstem, thalamus, and the bilateral cerebellum using FDG-PET in people with post-COVID-19 symptoms (Guedj et al. 2021). Importantly, this hypo-metabolism was associated with the patients’ symptoms (e.g., hyposmia/anosmia, cognitive impairment, pain and insomnia) (Guedj et al. 2021)."

 

sorry for the delay in answering . here is the study

 

Hmm I'm thinking a better conclusion might have been that the method used was unable and unsuitable to identifying or helping to elucidate in any way the symptoms patients experience. Not that there is some problem with patients perceptions of their own experience, which is I suspect how many will read and interpret the paper's results.

 

Hi Hutan, thank you for the welcome. No I don't have an association with the study, I just saw the discussion and wanted to know what people thought once they had seen the whole thing. It just resonates with my husband's symptoms that almost everything seems to be a problem with his brain not functioning properly.