Hazendonk, K M, Crowe, S F · Neuropsychiatry, neuropsychology, and behavioral neurology · 2000
This study compared how well people with postpolio syndrome could think and remember compared to polio survivors without the condition and healthy controls. Although people with postpolio syndrome reported mental fatigue and memory problems, standard tests of thinking and memory showed no real differences between the groups. The researchers found that depression and worry about illness were more common in the postpolio syndrome group and may explain why patients feel cognitively impaired.
This study is relevant to ME/CFS because both conditions feature prominent subjective cognitive complaints ('brain fog' or 'mental fatigue') despite unclear objective cognitive deficits. The finding that depression and illness-related distress may explain reported cognitive difficulties—rather than actual neurological damage—informs clinical interpretation of cognitive complaints in postinfectious illnesses and suggests that mood-focused interventions could be important. Understanding the relationship between subjective and objective cognition helps clinicians and patients accurately assess and manage cognitive symptoms.
This study does not prove that cognitive complaints are purely psychological or 'not real'—subjective cognitive impairment is a genuine clinical symptom regardless of objective test results. It does not establish causation or definitively prove depression causes cognitive complaints; depression and cognitive complaints could share a common underlying mechanism. The cross-sectional design means we cannot determine the temporal relationship between depression and cognitive symptoms, and results specific to postpolio syndrome may not directly translate to ME/CFS.
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
Hazendonk, K M & Crowe, S F (2000). A neuropsychological study of the postpolio syndrome: support for depression without neuropsychological impairment.. Neuropsychiatry, neuropsychology, and behavioral neurology. https://pubmed.ncbi.nlm.nih.gov/10780629/
BibTeX
@article{mecfsatlas-hazendonk-2000-neuropsychological-study,
author = {Hazendonk, K M and Crowe, S F},
title = {A neuropsychological study of the postpolio syndrome: support for depression without neuropsychological impairment.},
journal = {Neuropsychiatry, neuropsychology, and behavioral neurology},
year = {2000},
note = {PubMed: 10780629},
url = {https://www.mecfsatlas.com/evidence/hazendonk-2000-neuropsychological-study},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/hazendonk-2000-neuropsychological-study
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