Altay, H T, Toner, B B, Brooker, H et al. · International journal of psychiatry in medicine · 1990 · DOI
This study looked at whether ME/CFS patients who reported memory and concentration problems actually showed these difficulties when tested. Surprisingly, the patients performed better than average on standard cognitive tests, even though they felt they had cognitive problems. The researchers suggested that psychological factors might explain why patients' subjective experience didn't match their test results.
This study directly addresses a common and distressing symptom in ME/CFS—cognitive dysfunction (often called 'brain fog')—by attempting objective measurement. Understanding whether cognitive complaints reflect actual impairment or other factors is crucial for validating patient experiences and guiding appropriate treatment approaches.
This study does not prove that cognitive complaints are purely psychological or without physiological basis. The cross-sectional design cannot establish causation, and the lack of comparison groups (healthy controls, other chronic illnesses) limits interpretation. Additionally, cognitive testing on a single occasion may not capture fluctuating symptoms or cognitive fatigue that worsens with exertion, which is characteristic of 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 →
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