Johnson, S K, DeLuca, J, Fiedler, N et al. · Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 1994 · DOI
Many people with ME/CFS experience brain fog and difficulty thinking clearly, which can be just as disabling as physical symptoms. This review examined research on these cognitive problems and found that the issue may not be with memory itself, but rather with how the brain processes information—like a computer that struggles to handle incoming data quickly enough. Understanding this difference is important for developing better treatments and support strategies.
Cognitive dysfunction ('brain fog') is one of the most debilitating symptoms for many ME/CFS patients, yet it is often underrecognized. This study helps distinguish whether cognitive problems stem from memory loss or processing difficulties, which has implications for how researchers investigate the underlying biology and how clinicians can better support patients with targeted strategies.
This narrative review does not establish causation or identify the biological mechanisms causing impaired information processing. It also does not measure the severity or prevalence of cognitive dysfunction in the broader ME/CFS population, and conclusions depend on the quality and scope of studies included in the review.
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
Johnson, S K, DeLuca, J, Fiedler, N, & Natelson, B H (1994). Cognitive functioning of patients with chronic fatigue syndrome.. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. https://doi.org/10.1093/clinids/18.supplement_1.s84
BibTeX
@article{mecfsatlas-johnson-1994-cognitive-functioning,
author = {Johnson, S K and DeLuca, J and Fiedler, N and Natelson, B H},
title = {Cognitive functioning of patients with chronic fatigue syndrome.},
journal = {Clinical infectious diseases : an official publication of the Infectious Diseases Society of America},
year = {1994},
doi = {10.1093/clinids/18.supplement_1.s84},
note = {PubMed: 8148459},
url = {https://www.mecfsatlas.com/evidence/johnson-1994-cognitive-functioning},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/johnson-1994-cognitive-functioning
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