Samii, A, Wassermann, E M, Ikoma, K et al. · Neurology · 1996 · DOI
This study measured how the brain's motor cortex responds to exercise using magnetic stimulation in people with ME/CFS, depressed patients, and healthy controls. After exercise, healthy people showed a much stronger increase in brain activity (218%), while ME/CFS patients showed a weaker increase (126%), suggesting their brains may not respond as vigorously to physical exertion as they should.
This mechanistic study provides neurobiological evidence that ME/CFS involves abnormal central nervous system responses to exercise, distinct from normal fatigue. Understanding how the brain responds differently to exertion in ME/CFS may help explain post-exertional malaise and guide development of targeted interventions.
This study does not establish whether reduced cortical excitability is specific to ME/CFS or a general feature of chronic illness and depression. The cross-sectional design cannot determine if altered motor responses cause ME/CFS symptoms or result from the disease. The findings do not directly measure post-exertional malaise or explain the clinical mechanisms of symptom worsening after activity.
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
Samii, A, Wassermann, E M, Ikoma, K, Mercuri, B, George, M S, O'Fallon, A, et al. (1996). Decreased postexercise facilitation of motor evoked potentials in patients with chronic fatigue syndrome or depression.. Neurology. https://doi.org/10.1212/wnl.47.6.1410
BibTeX
@article{mecfsatlas-samii-1996-decreased-postexercise,
author = {Samii, A and Wassermann, E M and Ikoma, K and Mercuri, B and George, M S and O'Fallon, A and Dale, J K and Straus, S E and Hallett, M},
title = {Decreased postexercise facilitation of motor evoked potentials in patients with chronic fatigue syndrome or depression.},
journal = {Neurology},
year = {1996},
doi = {10.1212/wnl.47.6.1410},
note = {PubMed: 8960719},
url = {https://www.mecfsatlas.com/evidence/samii-1996-decreased-postexercise},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/samii-1996-decreased-postexercise
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