Sejvar, James J, Curns, Aaron T, Welburg, Leonie et al. · Journal of neuropsychology · 2008 · DOI
This study looked at 54 people who had recovered from West Nile virus infection about 1.5 years after getting sick. Researchers tested their memory, thinking skills, and quality of life. They found that half of the mildly ill patients and three-quarters of those with more severe illness still had ongoing symptoms and problems with daily functioning, even though most performed normally on formal cognitive tests.
This study is relevant to ME/CFS research because it documents a pattern seen in both West Nile virus and CFS: persistent symptoms and functional impairment despite normal or near-normal performance on standard cognitive tests. Understanding this dissociation may help explain why ME/CFS patients often report cognitive difficulties that do not show up on conventional neuropsychological testing, and suggests that current cognitive assessment methods may not capture the subtle impairments or disease mechanisms underlying post-viral illnesses.
This study does not prove that subjective cognitive complaints are purely psychological or non-organic; rather, it shows that standard neuropsychological tests may not be sensitive enough to detect the underlying pathology. It also does not establish the specific mechanisms causing persistent symptoms, nor does it prove that West Nile virus and CFS share identical neurocognitive pathologies—only that both show similar patterns of subjective versus objective dissociation. The cross-sectional design at 18 months does not establish whether impairments persist long-term or resolve with further 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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