Azcue, N, Gómez-Esteban, J C, Acera, M et al. · Journal of translational medicine · 2022 · DOI
This study compared brain fog and fatigue symptoms in people with ME/CFS and those recovering from COVID-19 to see if they might be the same condition triggered by different causes. Both groups showed similar problems with fatigue, sleep, and muscle pain, but people with ME/CFS had more severe cognitive difficulties like trouble concentrating and processing information. Interestingly, loss of smell that lasted a long time in COVID-19 patients appeared connected to their cognitive problems.
This study provides evidence that ME/CFS and post-COVID-19 condition may share similar underlying pathophysiology despite different triggers, which could inform treatment strategies and research priorities. Understanding the cognitive patterns specific to each condition helps validate brain fog as a measurable symptom rather than psychological, potentially improving clinical recognition and patient support. The potential link between olfactory dysfunction and cognitive decline offers a new avenue for understanding post-viral neurological sequelae.
This cross-sectional study does not establish causation or whether these conditions share an identical underlying mechanism—it only shows similarities in symptom patterns and cognitive impairment. The study cannot prove that loss of smell causes cognitive decline in COVID-19 patients; it only demonstrates correlation. The findings also cannot be generalized to all ME/CFS or post-COVID-19 patients, as this represents a specific sample at one time point.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Azcue, N, Gómez-Esteban, J C, Acera, M, Tijero, B, Fernandez, T, Ayo-Mentxakatorre, N, et al. (2022). Brain fog of post-COVID-19 condition and Chronic Fatigue Syndrome, same medical disorder?. Journal of translational medicine. https://doi.org/10.1186/s12967-022-03764-2
BibTeX
@article{mecfsatlas-azcue-2022-brain-fog,
author = {Azcue, N and Gómez-Esteban, J C and Acera, M and Tijero, B and Fernandez, T and Ayo-Mentxakatorre, N and Pérez-Concha, T and Murueta-Goyena, A and Lafuente, J V and Prada, Á and López de Munain, A and Ruiz-Irastorza, G and Ribacoba, L and Gabilondo, I and Del Pino, R},
title = {Brain fog of post-COVID-19 condition and Chronic Fatigue Syndrome, same medical disorder?},
journal = {Journal of translational medicine},
year = {2022},
doi = {10.1186/s12967-022-03764-2},
note = {PubMed: 36474290},
url = {https://www.mecfsatlas.com/evidence/azcue-2022-brain-fog},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/azcue-2022-brain-fog
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