Fatigue acts as a distractor in monotonous and dual attention tasks in patients with multiple sclerosis but not with LC, 2024, Helmut Hildebrandt

[Mij]

Abstract and Figures
Background: Fatigue associated with long COVID-19 has become an issue of great concern. Fatigue is also a consequence of multiple sclerosis (MS), leading to reduced quality of life and early retirement. Based on our model of fatigue [15], we hypothesized that the severity of fatigue in both diseases is related to performance on monotonous attention tasks and in one of the two streams of a divided attention task, but not on other cognitive tasks.

Method: In this retrospective study, we analyzed the relationship between subjective cognitive fatigue and neuro-psychological test results in two groups of patients (Long COVID: n = 35; MS: n = 50), controlling for depressive mood. Age-, sex-and education-corrected percentile scores were used, first for both groups combined and then for the two groups separately.

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[SNT Gatchaman]

The link to the published article on the journal site appears to be behind a paywall, but the authors have posted on ResearchGate, as linked above by Mij. I've expanded the abstract.

Fatigue acts as a distractor in monotonous and dual attention tasks in patients with multiple sclerosis but not with long COVID
H Hildebrandt; K Hanken; T Duning; H Stuke; P Eling

BACKGROUND
Fatigue associated with long COVID-19 has become an issue of great concern. Fatigue is also a consequence of multiple sclerosis (MS), leading to reduced quality of life and early retirement. Based on our model of fatigue [15], we hypothesized that the severity of fatigue in both diseases is related to performance on monotonous attention tasks and in one of the two streams of a divided attention task, but not on other cognitive tasks.

METHODS
In this retrospective study, we analyzed the relationship between subjective cognitive fatigue and neuropsychological test results in two groups of patients (Long COVID: n = 35; MS: n = 50), controlling for depressive mood. Age-, sex- and education-corrected percentile scores were used, first for both groups combined and then for the two groups separately.

RESULTS
Both patient groups did not differ in age, depression score, and severity of fatigue. As predicted, we found an association between cognitive fatigue and reaction times in the monotonous attention task and, for the first time, between cognitive fatigue and one stream of the divided attention test. Post hoc analysis showed that these correlations were not significant in the long COVID group. None of the other neuropsychological test scores correlated with fatigue.

CONCLUSIONS
Cognitive fatigue in patients with MS and Long Covid can be objectified using monotonous tests or a divided attention task. Future studies could vary the salience of the two streams to be processed in divided attention tasks to increase their sensitivity and specificity for measuring cognitive fatigue.

Link | PDF (Neurologie und Rehabilitation via ResearchGate)

 

[SNT Gatchaman]

Based on our model of fatigue [15]

The Representation of Inflammatory Signals in the Brain – A Model for Subjective Fatigue in Multiple Sclerosis (2014)
Hanken, Katrin; Eling, Paul; Hildebrandt, Helmut

In multiple sclerosis (MS) patients, fatigue is rated as one of the most common and disabling symptoms. However, the pathophysiology underlying this fatigue is not yet clear.

Several lines of evidence suggest that immunological factors, such as elevated levels of pro-inflammatory cytokines, may contribute to subjective fatigue in MS patients. Pro-inflammatory cytokines represent primary mediators of immune-to-brain-communication, modulating changes in the neurophysiology of the central nervous system.

Recently, we proposed a model arguing that fatigue in MS patients is a subjective feeling, which is related to inflammation. Moreover, it implies that fatigue can be measured behaviorally only by applying specific cognitive tasks related to alertness and vigilance.

In the present review, we focus on the subjective feeling of MS-related fatigue. We examine the hypothesis that the subjective feeling of MS-related fatigue may be a variant of inflammation-induced sickness behavior, resulting from cytokine-mediated activity changes within brain areas involved in interoception and homeostasis including the insula, the anterior cingulate, and the hypothalamus.

We first present studies demonstrating a relationship between pro-inflammatory cytokines and subjective fatigue in healthy individuals, in people with inflammatory disorders, and particularly in MS patients. Subsequently, we discuss studies analyzing the impact of anti-inflammatory treatment on fatigue.

In the next part of this review, we present studies on the transmission and neural representation of inflammatory signals, with a special focus on possible neural concomitants of inflammation-induced fatigue. We also present two of our studies on the relationship between local gray and white matter atrophy and fatigue in MS patients. Finally, we discuss some implications of our findings and future perspectives.


Link | PDF (Frontiers in Neurology) [Open Access]

 

[SNT Gatchaman]

See also Comments on energy conservation treatments for MS-related fatigue and a new proposal (2024, Journal of the Neurological Sciences)

 

[Hutan]

I think that ambiguous title just means that the reported level of cognitive fatigue negatively correlates with performance on a couple of specific cognitive function tests (more reported cognitive fatigue = a reduced performance) in MS but not in Long Covid. However, I don't think it can be concluded that the fatigue of some people with long Covid doesn't also negatively correlate with performance on e.g. the monotonous attention task.

As predicted, we found an association between cognitive fatigue and reaction times in the monotonous attention task and, for the first time, between cognitive fatigue and one stream of the divided attention test. Post hoc analysis showed that these correlations were not significant in the long COVID group.

One reason is that the Long Covid group in this study is substantially smaller than the MS group (35 versus 50). If the samples had been the same size, the finding in the LC group might have been statistically significant.

Another is that the Long Covid group will almost certainly include people with a range of problems, and so you would need a larger sample to get rid of the noise.

Another is that they controlled for depressive mood and corrected for other things. Goodness knows what that did to the data. So that may have dampened the signal in the LC group.


The good thing about this study is that it identifies two tests that may show cognitive dysfunction in LC and ME/CFS: the monotonous attention task and a dual attention task.