Klebek, Lauren, Sunnquist, Madison, Jason, Leonard A · Fatigue : biomedicine, health & behavior · 2019 · DOI
This study compared three similar long-term illnesses that cause fatigue and muscle problems: Post-polio syndrome (PPS), ME, and CFS. Researchers used questionnaires and computer analysis to identify which symptoms best distinguish these conditions from each other. They found that people with ME/CFS tend to have more severe overall functional impairment than those with PPS, and that three specific areas—brain fog, post-exertional malaise (getting worse after activity), and hormone-related symptoms—are most helpful in telling these illnesses apart.
Accurate differential diagnosis among ME/CFS, PPS, and similar conditions remains clinically challenging due to overlapping symptoms. This study identifies specific symptom domains—particularly PEM and neurocognitive dysfunction—that may improve diagnostic accuracy and guide targeted treatment approaches for ME/CFS patients who are frequently misdiagnosed or grouped with other conditions.
This study does not establish causal mechanisms underlying symptom differences or explain why these domains distinguish the illnesses. The cross-sectional design cannot determine whether observed differences reflect disease pathophysiology or other factors. Additionally, findings describe group-level patterns and may not apply reliably to individual diagnostic cases.
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
Klebek, Lauren, Sunnquist, Madison, & Jason, Leonard A (2019). Differentiating Post-Polio Syndrome from Myalgic Encephalomyelitis and Chronic Fatigue Syndrome.. Fatigue : biomedicine, health & behavior. https://doi.org/10.1080/21641846.2019.1687117
BibTeX
@article{mecfsatlas-klebek-2019-differentiating-post,
author = {Klebek, Lauren and Sunnquist, Madison and Jason, Leonard A},
title = {Differentiating Post-Polio Syndrome from Myalgic Encephalomyelitis and Chronic Fatigue Syndrome.},
journal = {Fatigue : biomedicine, health & behavior},
year = {2019},
doi = {10.1080/21641846.2019.1687117},
note = {PubMed: 33014628},
url = {https://www.mecfsatlas.com/evidence/klebek-2019-differentiating-post},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/klebek-2019-differentiating-post
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