SynthesisMedicine2026
Prevalence and long-term outcomes of brain fog and cognitive impairment in individuals with long COVID: A systematic review.
Synthesis in Medicine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
1 citing paper in PubMed.
- Neurological Manifestations of Long COVID: Current Evidence, Emerging Concepts, and Future Perspectives.Journal of clinical medicine · 2026Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundLong COVID is increasingly recognized as a complex multisystem condition, with brain fog and cognitive impairment emerging as some of its manifestations. Despite growing literature, the pooled prevalence, subgroup differences, and underlying mechanisms remain incompletely understood.
methodsWe systematically reviewed 47 studies (2000-2025) encompassing over 25,000 patients to evaluate the prevalence of brain fog and cognitive impairment among long COVID populations. Data were extracted on study design, patient demographics, follow-up duration, and subgroup variables including gender, hospitalization, vaccination, and geographic region. Risk of bias was assessed using the Newcastle-Ottawa Scale (NOS v9.0) and JBI checklists. Quantitative synthesis was performed with subgroup and temporal analyses, presented in forest plots and summary figures.
resultsThe pooled prevalence of brain fog was 30% (95% CI: 28-32), while cognitive impairment was 25% (95% CI: 23-27). Female patients consistently showed higher rates compared to males (34% vs 23% for brain fog; 29% vs 21% for cognitive impairment). Community-managed patients demonstrated higher prevalence compared to hospitalized cohorts, and unvaccinated individuals had a greater burden than vaccinated ones. Temporal analyses indicated that prevalence increased with longer follow-up, suggesting symptom persistence or late manifestation. Pathophysiological explanations include neuroinflammation, microvascular injury, immune dysregulation, and psychosocial stressors.
conclusionBrain fog and cognitive impairment are common, persistent, and clinically significant features of long COVID. Gender differences, vaccination status, and follow-up duration influence prevalence. Future studies should focus on mechanisms, preventive strategies, and targeted interventions to mitigate long-term cognitive sequelae.
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Registered trials
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