Jason, L A, Tryon, W W, Taylor, R R et al. · Psychological reports · 1999 · DOI
This study asked one person with ME/CFS to track their symptoms hourly and daily to understand what makes fatigue better or worse. Researchers found that energy levels, physical activity, and mental effort were closely connected to how tired the person felt. This detailed tracking method could help doctors and researchers better understand ME/CFS patterns.
This study demonstrates the feasibility and potential value of intensive symptom monitoring in ME/CFS, which could inform personalized management strategies and help identify individual symptom patterns. The methodology addresses longstanding research challenges in ME/CFS by capturing real-time symptom fluctuations rather than relying on retrospective recall, potentially improving future study designs.
This case study does not establish that perceived energy, exertion, or fatigue have causal relationships—only that they correlate. The single-subject design cannot determine whether these patterns apply to other ME/CFS patients, and the study provides no evidence about underlying biological mechanisms driving these correlations.
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
Jason, L A, Tryon, W W, Taylor, R R, King, C, Frankenberry, E L, & Jordan, K M (1999). Monitoring and assessing symptoms of chronic fatigue syndrome: use of time series regression.. Psychological reports. https://doi.org/10.2466/pr0.1999.85.1.121
BibTeX
@article{mecfsatlas-jason-1999-monitoring-assessing,
author = {Jason, L A and Tryon, W W and Taylor, R R and King, C and Frankenberry, E L and Jordan, K M},
title = {Monitoring and assessing symptoms of chronic fatigue syndrome: use of time series regression.},
journal = {Psychological reports},
year = {1999},
doi = {10.2466/pr0.1999.85.1.121},
note = {PubMed: 10575979},
url = {https://www.mecfsatlas.com/evidence/jason-1999-monitoring-assessing},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/jason-1999-monitoring-assessing
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