Jain, S S, DeLisa, J A · American journal of physical medicine & rehabilitation · 1998 · DOI
This review examined over 200 scientific studies about ME/CFS to understand what we know about the condition, particularly focusing on thinking problems and exercise. The authors found that while patients often report cognitive difficulties, actual measured problems are subtle and mainly affect how quickly the brain processes complex information. Brain imaging studies suggest changes may occur in the white matter of the brain rather than in the muscles themselves.
This review synthesizes early evidence that ME/CFS may involve brain changes rather than simple muscle weakness, supporting the biological basis of the condition and validating patient-reported cognitive symptoms. It highlights the critical need for better research methodology and careful study of exercise effects, directly informing how clinicians should approach both diagnosis and treatment recommendations for ME/CFS patients.
This literature review does not definitively prove what causes ME/CFS or establish whether cognitive deficits are caused by central nervous system changes versus deconditioning, as the authors themselves note these remain difficult to separate. The review does not establish clear diagnostic criteria for ME/CFS or demonstrate that exercise uniformly exacerbates or improves the condition. As a narrative review rather than a systematic analysis, it does not quantify the strength of evidence across studies or account for publication bias.
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
Jain, S S & DeLisa, J A (1998). Chronic fatigue syndrome: a literature review from a physiatric perspective.. American journal of physical medicine & rehabilitation. https://doi.org/10.1097/00002060-199803000-00018
BibTeX
@article{mecfsatlas-jain-1998-chronic-fatigue,
author = {Jain, S S and DeLisa, J A},
title = {Chronic fatigue syndrome: a literature review from a physiatric perspective.},
journal = {American journal of physical medicine & rehabilitation},
year = {1998},
doi = {10.1097/00002060-199803000-00018},
note = {PubMed: 9558019},
url = {https://www.mecfsatlas.com/evidence/jain-1998-chronic-fatigue},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-27. https://www.mecfsatlas.com/evidence/jain-1998-chronic-fatigue
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