Barofsky, I, Legro, M W · Reviews of infectious diseases · 1991 · DOI
This paper examines how fatigue is defined and measured in ME/CFS, highlighting that these definitions have not been well-developed in medical research. The authors reviewed different tools available to measure fatigue—ranging from simple single-item questions to more complex multi-part assessments—and discussed how fatigue in ME/CFS differs from fatigue studied in healthy people in laboratory settings. They emphasize the need to study fatigue as it actually occurs in patients with ME/CFS and to use consistent measurement methods across research.
Accurate measurement of fatigue is fundamental to understanding ME/CFS, diagnosing the condition, and evaluating treatment effectiveness. This foundational paper highlights why developing consistent, validated fatigue assessment tools matters for ensuring that research findings are comparable and clinically meaningful across studies.
This review paper does not establish what causes fatigue in ME/CFS, nor does it determine whether the relationship between psychiatric illness and ME/CFS is causal or coincidental. It also does not validate any specific measurement tool or prove that standardized assessments will resolve current diagnostic challenges—it only recommends their use.
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
Barofsky, I & Legro, M W (1991). Definition and measurement of fatigue.. Reviews of infectious diseases. https://doi.org/10.1093/clinids/13.supplement_1.s94
BibTeX
@article{mecfsatlas-barofsky-1991-definition-measurement,
author = {Barofsky, I and Legro, M W},
title = {Definition and measurement of fatigue.},
journal = {Reviews of infectious diseases},
year = {1991},
doi = {10.1093/clinids/13.supplement_1.s94},
note = {PubMed: 2020809},
url = {https://www.mecfsatlas.com/evidence/barofsky-1991-definition-measurement},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/barofsky-1991-definition-measurement
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