ORIGINAL RESEARCH article
Front. Psychiatry
Sec. Neuroimaging
This article is part of the Research TopicBrain Circuitry and Neuropsychiatric Outcomes in COVID-19View all 7 articles
Brain Fog Symptoms in Individuals With and Without Post COVID-19 Condition: Translation and Validation of the Brain Fog Scale
Provisionally accepted
- 1University of Cyprus, Nicosia, Cyprus
- 2Center for Applied Neuroscience, University of Cyprus, Nicosia, Cyprus
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Introduction: Brain fog describes a heterogenous symptom encompassing cognitive symptoms, mental fatigue and reduced mental clarity, particularly prevalent among individuals with Post COVID – 19 Condition (PCC). This study aimed to translate and validate the Brain Fog Scale (BFS), originally developed in Polish, among a Greek-speaking population and explore whether individuals diagnosed with PCC report significantly more brain fog symptoms, compared to those without PCC. Methods: The BFS was translated in Greek, using a forward – backward translation process and was administered online. Principal Component Analysis and Confirmatory Factor Analysis were run to assess factor structure. Results: A total of 602 individuals (76.6% female) completed the BFS, of which 36 had a self-reported diagnosis of PCC. Internal consistency for the entire sample was excellent, α = 0.96. The BFS largely retained its original three factor structure with little variability: (1) impaired cognitive acuity (α = 0.95), (2) inattentiveness (α = 0.92), (3) mental exhaustion (α = 0.84). A Mann-Whitney U test revealed that individuals diagnosed with PCC reported significantly more brain fog symptoms compared to those without PCC, U = 2178.50, p = .011. MANOVA analyses further indicated significantly higher scores in the impaired cognition Factor among individuals with PCC, F(1, 125) = 7.32, p = .008. Conclusion: The BFS comprises a valid tool for assessment of brain fog and can facilitate person-centred rehabilitation planning in PCC. Findings are discussed in relation to the literature regarding brain fog symptom burden in PCC with suggestions for future research made.
Keywords: brain fog, cognitive impairment, COVID – 19, Neurocognitive ability, Post COVID – 19 Condition
Received: 07 Aug 2025; Accepted: 09 Feb 2026.
Copyright: © 2026 Loizidou, Solomou, Nikolaou and Constantinidou. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Fofi Constantinidou
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