Cognitive functioning in patients with chronic fatigue syndrome: Slowed information processing or a deficit in attentional selectivity?, 2025, Banovic

https://psycnet.apa.org/doiLanding?doi=10.1037/neu0000982 paywall

APA PsycArticles: Journal Article
Cognitive functioning in patients with chronic fatigue syndrome: Slowed information processing or a deficit in attentional selectivity?
Banovic, I., Šaban, I., Ayad, A., Fornasieri, I., Parris, B. A., Tourny, C., & Augustinova, M. (2025). Cognitive functioning in patients with chronic fatigue syndrome: Slowed information processing or a deficit in attentional selectivity? Neuropsychology, 39(2), 152–161. https://doi.org/10.1037/neu0000982

Objective:

By addressing numerous statistical, theoretical, and methodological weaknesses of existing research on chronic fatigue syndrome (CFS), this study attempted to examine closely whether cognitive dysfunction in CFS patients is restricted to slowed information processing or whether it extends to less efficient attentional selectivity. Method: In an online study, 83 CFS patients and 83 healthy controls (all French-speaking volunteers) first completed the Multidimensional Chronic Asthenia Scale and then performed the two-to-one version of the Stroop task known to carefully measure different components of the Stroop effect including the targeted Stroop interference (i.e., prima facie indicators of attentional selectivity).

Results:

Adequately powered analyses of raw reaction times pointed to differences in the magnitude of Stroop interference between CFS patients and healthy controls. However, these differences are entirely explained by generally slower processing speed in CFS patients. Indeed, no such differences were found when standardized (i.e., z scored) reaction times that take into account preexisting differences in processing speed were analyzed, and this absence of differences was attested—for the first time—by strong Bayesian evidence in favor of the null.

Conclusion:

Although the present study showed that attentional selectivity is not impaired in CFS patients and that their cognitive dysfunction is restricted to slowed information processing, other studies are still needed to fully understand cognitive impairments associated with CFS. (PsycInfo Database Record (c) 2025 APA, all rights reserved)

Impact Statement

Key Points—Question:

There is a long-lasting question of whether cognitive functioning in patients with chronic fatigue syndrome is characterized by a slowed information processing or by an additional deficit in attentional selectivity.

Findings:

Performance of patients with chronic fatigue syndrome was slower compared with that of healthy controls. After controlling statistically for these differences, no further differences were found between patients with chronic fatigue syndrome and their healthy counterparts.

Importance:

The present study unambiguously showed that attentional selectivity is not impaired in patients with chronic fatigue syndrome and that their cognitive dysfunction is restricted to slowed information processing.

Next Steps:

Whether this reflects preservation or compensation is yet unknown. Therefore, future work is needed to address this issue and, more generally, to fully understand cognitive impairments associated with chronic fatigue syndrome.

 

I’m not familiar with these concepts. Can anyone explain?

 

Interesting paper. The null result on attentional selectivity is surprising given previous research. The 2:1 mapping helps disaggregate response from semantic conflict, and it's a better sample size than many Stroop papers (initially n=90 in both groups, with some exclusions taking both groups down to 83) and the authors demonstrate that it is adequately powered. The Bayesian analysis is something that I haven't often seen in this kind of research. The result doesn't preclude compensatory processes (in the discussion the authors suggest that patients may be compensating via additional neural recruitment or altered attentional-control strategies).

Two caveats: as the authors state, they did not systematically collect data regarding medication use or comorbidities that could alter psychomotor speed or attention. Secondly, with regard to the inclusion criteria:

The description of "CFS/ME/SEID patients" as "patients presenting a disease-unrelated [chronic asthenia]" doesn't fill me with confidence, and it would certainly have helped to establish whether they met modern diagnostic criteria.

There was a significant correlation between self-report on the MCAS scale and observed processing speed:

 

«Indeed, these results indicate that CFS/ME/SEID patients are experts in the analysis of their fatigue, its levels, and its possible consequences and adjust their subsequent performance—balancing speed and accuracy in the Stroop task—accordingly.»

I just want to repeat this.