SynthesisThe Laryngoscope2022
Neuroradiological Basis of COVID-19 Olfactory Dysfunction: A Systematic Review and Meta-Analysis.
Synthesis in The Laryngoscope, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers, 4 of them syntheses that pooled it.
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.
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Who cites it
12 citing papers in PubMed, 4 syntheses or guidelines pooled it, 30 citations in OpenAlex.
- Olfactory Impairment and Incident Cognitive Decline: A Systematic Review and Meta-Analysis.International forum of allergy & rhinology · 2025Pooled it
- Brain MRI findings in neurologically symptomatic COVID-19 patients: a systematic review and meta-analysis.Journal of neurology · 2023Pooled it
- Olfactory system measurements in COVID-19: a systematic review and meta-analysis.Neuroradiology · 2023Pooled it
- Prognosis and persistence of smell and taste dysfunction in patients with covid-19: meta-analysis with parametric cure modelling of recovery curves.BMJ (Clinical research ed.) · 2022Pooled it
- Subphenotypes of self-reported symptoms and outcomes in long COVID: a prospective cohort study with latent class analysis.BMJ open · 2024Observational
- A Comprehensive Review of COVID-19-Related Olfactory Deficiency: Unraveling Associations with Neurocognitive Disorders and Magnetic Resonance Imaging Findings.Diagnostics (Basel, Switzerland) · 2024Review
- Long COVID-19-related and non-COVID-19 postviral olfactory dysfunction a comparative MRI study focusing on the olfactory cleft and bulbs.Frontiers in neurology · 2024Article
- Altered structural connectivity in olfactory disfunction after mild COVID-19 using probabilistic tractography.Scientific reports · 2023Article
- Persistent post-COVID-19 dysosmia: Practices survey of members of the French National Union of Otorhinolaryngology-Head and Neck Surgery Specialists. CROSS analysis.European annals of otorhinolaryngology, head and neck diseases · 2023Article
- SARS-CoV-2 S1 protein causes brain inflammation by reducing intracerebral acetylcholine production.iScience · 2023Article
- Short Communication: Stellate Ganglion Blockade for Persistent Olfactory and Gustatory Symptoms Post-COVID-19.Local and regional anesthesia · 2023Article
- COVID-19 Smell Impairment and Crosstalk with Hypoxia Physiology.Life (Basel, Switzerland) · 2022Article
Corrections and comments
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Authors and funding
11 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectiveOlfactory dysfunction (OD) is a common presenting symptom of COVID-19 infection. Radiological imaging of the olfactory structures in patients with COVID-19 and OD can potentially shed light on its pathogenesis, and guide clinicians in prognostication and intervention.
methodsPubMed, Embase, Cochrane, SCOPUS were searched from inception to August 1, 2021. Three reviewers selected observational studies, case series, and case reports reporting radiological changes in the olfactory structures, detected on magnetic resonance imaging, computed tomography, or other imaging modalities, in patients aged ≥18 years with COVID-19 infection and OD, following preferred reporting items for systematic reviews and meta-analyses guidelines and a PROSPERO-registered protocol (CRD42021275211). We described the proportion of radiological outcomes, and used random-effects meta-analyses to pool the prevalence of olfactory cleft opacification, olfactory bulb signal abnormalities, and olfactory mucosa abnormalities in patients with and without COVID-19-associated OD.
resultsWe included 7 case-control studies (N = 353), 11 case series (N = 154), and 12 case reports (N = 12). The pooled prevalence of olfactory cleft opacification in patients with COVID-19 infection and OD (63%, 95% CI = 0.38-0.82) was significantly higher than that in controls (4%, 95% CI = 0.01-0.13). Conversely, similar proportions of cases and controls demonstrated olfactory bulb signal abnormalities (88% and 94%) and olfactory mucosa abnormalities (2% and 0%). Descriptive analysis found that 55.6% and 43.5% of patients with COVID-19 infection and OD had morphological abnormalities of the olfactory bulb and olfactory nerve, respectively, while 60.0% had abnormal olfactory bulb volumes.
conclusionOur findings implicate a conductive mechanism of OD, localized to the olfactory cleft, in approximately half of the affected COVID-19 patients. Laryngoscope, 132:1260-1274, 2022.
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