ReviewJournal of neurophysiology2022
COVID-19 and olfactory dysfunction: a looming wave of dementia?
Review in Journal of neurophysiology, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 31 papers, 2 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
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
31 citing papers in PubMed, 2 syntheses or guidelines pooled it, 48 citations in OpenAlex.
- Efficacy of Omega-3 supplementation in olfactory dysfunction: a systematic review of randomized controlled trials.BMC nutrition · 2025Pooled it
- The impact of the COVID-19 pandemic on mortality in people with dementia without COVID-19: a systematic review and meta-analysis.BMC geriatrics · 2022Pooled it
- Impacts of different treatment methods on patients with COVID-related olfactory dysfunction: a systematic review and network meta-analysis.Clinics (Sao Paulo, Brazil) · 2026Article
- Longitudinal evaluation of neurocognitive outcomes in a cohort with persistent post-COVID olfactory dysfunction.Scientific reports · 2026Article
- Persistent olfactory dysfunction as an indicator of cognitive impairment in long COVID-19 syndrome: implications for monitoring and rehabilitation.European archives of psychiatry and clinical neuroscience · 2026Article
- Review
- Olfactory Dysfunction After SARS-CoV-2 Infection in the RECOVER Adult Cohort.JAMA network open · 2025Article
- γ neuromodulations: unraveling biomarkers for neurological and psychiatric disorders.Military Medical Research · 2025Review
- Alpha-synuclein pathology and Parkinson's disease-related olfactory dysfunctions: an update on preclinical models and therapeutic approaches.Mammalian genome : official journal of the International Mammalian Genome Society · 2025Review
- Post-COVID-19 Hyposmia Does Not Exhibit Main Neurodegeneration Markers in the Olfactory Pathway.Molecular neurobiology · 2024Article
- Odor representation and coding by the mitral/tufted cells in the olfactory bulb.Journal of Zhejiang University. Science. B · 2024Review
- Identification of the needs of individuals affected by COVID-19.Communications medicine · 2024Article
- Article
- Olfactory and cognitive decrements in 1991 Gulf War veterans with gulf war illness/chronic multisymptom illness.Environmental health : a global access science source · 2024Article
- Human senses and sensors from Aristotle to the present.Frontiers in neurology · 2024Review
- Inflammation and olfactory loss are associated with at least 139 medical conditions.Frontiers in molecular neuroscience · 2024Article
- Integrating the patient's voice into the research agenda for treatment of chemosensory disorders.Chemical senses · 2024Article
- Understanding the olfactory role in post-COVID cognitive and neuropsychiatric manifestations.Frontiers in psychology · 2024Article
- Dementia and epilepsy following COVID-19 infection in a 25-year-old female: A case report.Clinical case reports · 2024Article
- Review
Corrections and comments
- Erratum issued
Authors and funding
1 author at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Olfactory dysfunction is a hallmark symptom of COVID-19 disease resulting from the SARS-CoV-2 virus. The cause of the sudden and usually temporary anosmia that most people suffer from COVID-19 is likely entirely peripheral-inflammation and other damage caused by the virus in the sensory epithelium inside the upper recesses of the nasal cavity can damage or prevent chemicals from properly activating the olfactory sensory neurons. However, persistent olfactory dysfunction from COVID-19, in the form of hyposmia and parosmia (decreased or altered smell) may affect as many as 15 million people worldwide. This epidemic of olfactory dysfunction is thus a continuing public health concern. Mounting evidence suggests that the SARS-CoV-2 virus itself or inflammation from the immune response in the nasal sensory epithelium may invade the olfactory bulb, likely via non-neuronal transmission. COVID-19-related long-term olfactory dysfunction and early damage to olfactory and limbic brain regions suggest a pattern of degeneration similar to that seen in early stages of Alzheimer's disease, Parkinson's disease, and Lewy body dementia. Thus, long-term olfactory dysfunction coupled with cognitive and emotional disturbance from COVID-19 may be the first signs of delayed onset dementia from neurodegeneration. Few treatments are known to be effective to prevent further degeneration, but the first line of defense against degeneration may be olfactory and environmental enrichment. There is a pressing need for more research on treatments for olfactory dysfunction and longitudinal studies including cognitive and olfactory function from patients who have recovered from even mild COVID-19.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.