Michiels, V, Cluydts, R, Fischler, B · Journal of the International Neuropsychological Society : JINS · 1998 · DOI
This study tested thinking and memory skills in 20 people with ME/CFS and compared them to 22 healthy people. The researchers found that people with ME/CFS had difficulty with attention tasks that required handling multiple pieces of information at once, and they performed worse on remembering spoken information. However, their ability to focus on a single thing while ignoring distractions appeared to work normally.
This study provides objective evidence that cognitive difficulties in ME/CFS are real and measurable, not imagined or purely psychological. Identifying which specific attention and memory processes are affected helps clinicians better understand patient reports of 'brain fog' and informs strategies for managing cognitive demands during illness.
This cross-sectional study cannot determine whether cognitive impairment is a direct cause of ME/CFS, a consequence of the illness, or related to other factors like deconditioning or medication effects. The study does not measure whether cognitive symptoms worsen with exertion (post-exertional malaise) or establish the underlying brain mechanisms responsible for the observed deficits.
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
Michiels, V, Cluydts, R, & Fischler, B (1998). Attention and verbal learning in patients with chronic fatigue syndrome.. Journal of the International Neuropsychological Society : JINS. https://doi.org/10.1017/s135561779845505x
BibTeX
@article{mecfsatlas-michiels-1998-attention-verbal,
author = {Michiels, V and Cluydts, R and Fischler, B},
title = {Attention and verbal learning in patients with chronic fatigue syndrome.},
journal = {Journal of the International Neuropsychological Society : JINS},
year = {1998},
doi = {10.1017/s135561779845505x},
note = {PubMed: 9745235},
url = {https://www.mecfsatlas.com/evidence/michiels-1998-attention-verbal},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-29. https://www.mecfsatlas.com/evidence/michiels-1998-attention-verbal
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