Grafman, J, Schwartz, V, Dale, J K et al. · Journal of neurology, neurosurgery, and psychiatry · 1993 · DOI
This study tested memory and thinking skills in 20 people with ME/CFS who reported memory problems. The researchers found that patients did have mild difficulty with memory tasks that required deep thinking and organization of information, but performed normally on other types of memory tests. Importantly, the severity of fatigue and other physical findings did not predict how well people performed on memory tests.
This study provides objective evidence that memory complaints in ME/CFS patients reflect genuine—though mild—cognitive impairment, rather than purely psychological factors. Understanding the specific type of memory affected (conceptual processing rather than basic memory storage) helps guide patient education and realistic expectations about cognitive function.
This small cross-sectional study does not establish causation or explain why conceptual memory processes are affected. The findings cannot be generalized to all CFS patients since only 20 participants were studied, and the study does not determine whether cognitive impairment predates illness onset or progresses over time.
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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