Wojcik, Grzegorz M, Shriki, Oren, Kwasniewicz, Lukasz et al. · Frontiers in neuroscience · 2023 · DOI
This study looked at brain electrical activity in people who had COVID-19 and experienced 'brain fog'—persistent mental cloudiness that can last several months. Researchers compared three groups using advanced brain scans while people performed thinking tasks, and used computer algorithms to see if they could distinguish between those with brain fog, those without it, and healthy controls. They found measurable differences in brain activity patterns between the groups, suggesting brain fog has a detectable physical basis in the brain.
Brain fog remains poorly understood in post-viral illnesses including ME/CFS, and this study provides objective electrophysiological evidence that cognitive complaints correlate with measurable brain activity changes. Developing biomarkers for brain fog could improve patient recognition, prognosis, and monitoring of recovery—critical for optimizing rehabilitation and return-to-function.
This study does not establish causation or mechanism—only that brain activity patterns differ between groups. The 60-70% classification accuracy means this approach cannot yet reliably diagnose brain fog in individual patients. The authors explicitly note that explaining *why* these differences exist requires much larger cohorts and additional investigation.
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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