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The relationship between persistent olfactory dysfunction associated with COVID-19 and olfactory bulb morphology

https://doi.org/10.33667/2078-5631-2025-15-61-66

Abstract

Olfactory disorders are more relevant than ever in the era of the pandemic of the new coronavirus infection (COVID-19). According to statistical data, about 60 % of patients complain of olfactory dysfunction (OD) in the acute period, while 6.2 % of patients note that complaints persist for more than a month after recovery from COVID-19. However, no more than 5 % of those with persistent OD seek medical help. Currently, the diagnosis of OD is difficult due to the lack of a single examination protocol. Attempts have been made to compare the MRI data of the olfactory nerve and the severity of OD, based on changes in the volume of the olfactory bulb (OB), at the same time, one should not forget that in addition to the volume of OB, it is possible to assess the morphology of OB, which changes in response to direct respiratory exposure. The article provides up-to-date information, including an assessment of 15 meta-analyses on the features of MRI diagnosis of OD associated with COVID-19, as well as the results of the authors' personal experience.

About the Authors

A. S. Adamova
North-Western State Medical University named after I. I. Mechnikov
Russian Federation

Adamova Anastasiya S., 4th year post-graduate student at Dept of Neurology n.a. S. N. Davidenkov



E. G. Klocheva
North-Western State Medical University named after I. I. Mechnikov
Russian Federation

Klocheva Elena G., DM Sci (habil.), professor at Dept of Neurology n.a. S. N. Davidenkov



V. V. Goldobin
North-Western State Medical University named after I. I. Mechnikov
Russian Federation

Goldobin Vitalii V., DM Sci (habil.), head of Dept of Neurology n.a. S. N. Davidenkov



References

1. Niimura Y., Nei M. Evolutionary dynamics of olfactory and other chemosensory receptor genes in vertebrates. J Hum Genet. 2006; 51 (6): 505–517. DOI: 10.1007/s10038-006-0391-8. Epub 2006 Apr 11.

2. Pinto J. M., Wroblewski K. E., Kern D. W. et al. Olfactory dysfunction predicts 5-year mortality in older adults. PLoS One. 2014 Oct 1; 9 (10): e107541. DOI: 10.1371/journal.pone.0107541

3. Stark R. The olfactory bulb: A neuroendocrine spotlight on feeding and metabolism. J Neuroendocrinol. 2024 Jun; 36 (6): e13382.DOI: 10.1111/jne.13382

4. Burges Watson D. L., Campbell M., Hopkins C. et al. Altered smell and taste: Anosmia, parosmia and the impact of long COVID-19/PLoS One. 2021 Sep 24; 16 (9): e0256998. DOI: 10.1371/journal.pone.0256998

5. Doty R. L. The olfactory vector hypothesis of neurodegenerative disease: is it viable? Ann Neurol. 2008 Jan; 63 (1): 7–15. DOI: 10.1002/ana.21327. PMID: 18232016

6. Petrocelli M., Ruggiero F., Baietti A. M. et al. Remote psychophysical evaluation of olfactory and gustatory functions in early-stage coronavirus disease 2019 patients: the Bologna experience of 300 cases. J Laryngol Otol. 2020 Jul; 134 (7): 571–576. DOI: 10.1017/S 0022215120001358

7. Cooper K. W., Brann D. H., Farruggia M. C. et al. COVID-19 and the Chemical Senses: Supporting Players Take Center Stage. Neuron. 2020 Jul 22; 107 (2): 219–233. DOI: 10.1016/j.neuron.2020.06.032

8. Frasnelli J., Hummel T. Olfactory dysfunction and daily life/Eur Arch Otorhinolaryngol. 2005 Mar;262(3):231–5.DOI: 10.1007/s00405–004–0796-y

9. Kobal G., Hummel T., Sekinger B. et al. «Sniffin' sticks»: screening of olfactory performance. Rhinology. 1996 Dec; 34 (4): 222–6.

10. Duprez T. P., Rombaux P. Imaging the olfactory tract (cranial nerve #1). Eur J Radiol. 2010 May; 74 (2): 288–98. DOI: 10.1016/j. ejrad.2009.05.065

11. Kandemirli S. G., Altundag A., Yildirim D. et al. Olfactory Bulb MRI and Paranasal Sinus CT Findings in Persistent COVID-19 Anosmia. Acad Radiol. 2021 Jan; 28 (1): 28–35. DOI: 10.1016/j.acra.2020.10.006

12. Morrison E. E., Costanzo R. M. Morphology of olfactory epithelium in humans and other vertebrates. Microsc Res Tech. 1992 Oct 1; 23 (1): 49–61. DOI: 10.1002/jemt.1070230105

13. Bushdid C., Magnasco M. O., Vosshall L. B. et al. Humans can discriminate more than 1 trillion olfactory stimuli. Science. 2014 Mar 21; 343 (6177): 1370–2. DOI: 10.1126/science.1249168

14. Sullivan S. L., Adamson M. C., Ressler K. J. et al. The chromosomal distribution of mouse odorant receptor genes. Proc Natl Acad Sci U S A. 1996 Jan 23; 93 (2): 884–8. DOI: 10.1073/pnas.93.2.884

15. Chehrehasa F., Key B., St John J. A. The shape of the olfactory bulb influences axon targeting/Brain Res. 2007 Sep 12; 1169: 17–23. DOI: 10.1016/j.brainres.2007.06.073.

16. Quintela R. M., Brunert D., Rothermel M. Functional role of the anterior olfactory nucleus in sensory information processing. Neuroforum. 2022; 28 (3): 169–175.DOI: 10.1515/nf-2022-0008

17. Kay L. M., Sherman S. M. An argument for an olfactory thalamus. Trends Neurosci. 2007; 30 (2): 47–53.DOI: 10.1016/j.tins.2006.11.007

18. Nagayama S., Takahashi Y. K., Yoshihara Y. et al. Mitral and tufted cells differ in the decoding manner of odor maps in the rat olfactory bulb/J Neurophysiol. 2004 Jun; 91 (6): 2532–40. DOI: 10.1152/jn.01266.2003

19. Radtsig E. Yu., Osipova E.P About the classification of olfactory disorders (based on domestic and foreign documents). Russian otorhinolaryngology. 2019; 100 (3): 87–92. (In Russ.).

20. Leopold D. Distortion of olfactory perception: diagnosis and treatment. Chem Senses. 2002 Sep; 27 (7): 611–5. DOI: 10.1093/chemse/27.7.611

21. Hernandez A. K., Landis B. N., Altundag A. et al. Olfactory Nomenclature: An Orchestrated Effort to Clarify Terms and Definitions of Dysosmia, Anosmia, Hyposmia, Normosmia, Hyperosmia, Olfactory Intolerance, Parosmia, and Phantosmia. Olfactory Hallucination. ORL J Otorhinolaryngol Relat Spec. 2023; 85 (6): 312–320. DOI: 10.1159/000530211

22. Whitcroft K. L., Altundag A., Balungwe P. et al. Position paper on olfactory dysfunction: 2023. Rhinology. 2023 Oct 1; 61 (33): 1–108. DOI: 10.4193/Rhin22.483

23. Mueller A., Rodewald A., Reden J. et al. Reduced olfactory bulb volume in post-traumatic and post-infectious olfactory dysfunction. Neuroreport. 2005 Apr 4; 16 (5): 475–8. DOI: 10.1 097/00001756-200504040-00011

24. Capelli S., Caroli A., Barletta A. et al. MRI evidence of olfactory system alterations in patients with COVID-19 and neurological symptoms. J Neurol. 2023 Mar; 270 (3): 1195–1206. DOI: 10.1007/s00415-023-11561-0

25. Hura N., Yi J. S., Lin S. Y. et al. Magnetic Resonance Imaging as a Diagnostic and Research Tool in Patients with Olfactory Dysfunction: A Systematic Review. Am J Rhinol Allergy. 2022 Sep; 36 (5): 668–683. DOI: 10.1177/19458924221096913

26. Frosolini A., Parrino D., Fabbris C. et al. Magnetic Resonance Imaging Confirmed Olfactory Bulb Reduction in Long COVID-19: Literature Review and Case Series. Brain Sci. 2022; 24 (4): 1–12. DOI: 10.3390/brainsci12040430

27. Muccioli L., Sighinolfi G., Mitolo M. et al. Cognitive and functional connectivity impairment in post-COVID-19 olfactory dysfunction. Neuroimage Clin. 2023; 37: 1–10. DOI: 10.1016/j. nicl.2023.103410

28. Yao L., Yi X., Pinto J. M. et al. Olfactory cortex and Olfactory bulb volume alterations in patients with post-infectious Olfactory loss. Brain Imaging Behav. 2018 Oct; 12 (5): 1355–1362. DOI: 10.1007/s11682-017-9807-7. PMID: 29234959.

29. Han P., Winkler N., Hummel C. et al. Alterations of Brain Gray Matter Density and Olfactory Bulb Volume in Patients with Olfactory Loss after Traumatic Brain Injury. J Neurotrauma. 2018 Nov 15; 35 (22): 2632–2640. DOI: 10.1089/neu.2017.5393

30. Akkaya H., Kizilog Lu A., Dilek O. et al. Evaluation of the olfactory bulb volume and morphology in patients with coronavirus disease 2019: can differences create predisposition to anosmia? Rev Assoc Med Bras (1992). 2021 Oct; 67 (10): 1491–1497. DOI: 10.1590/1806– 9282.20210678

31. Tan C. J., Tan B. K.J., Tan X. Y. et al. Neuroradiological Basis of COVID-19 Olfactory Dysfunction: A Systematic Review and Meta-Analysis. Laryngoscope. 2022 Jun; 132 (6): 1260–1274. DOI: 10.1002/lary.30078

32. Zatorre R. J., Jones-Gotman M., Evans A. C. et al. Functional localization and lateralization of human olfactory cortex. Nature. 1992 Nov 26; 360 (6402): 339–40. DOI: 10.1038/360339a0

33. Parlak A. E., Selçuk Ö. T., Yilmaz G. Ö. et al. Olfactory Bulb Volume and Morphology Changes in COVID-19 Patients With Olfactory Disorders Using Magnetic Resonance Imaging. J Comput Assist Tomogr. 2024 Mar–Apr 01; 48 (2): 317–322. DOI: 10.1097/RCT.0000000000001559

34. Wu A., Yu B., Komiyama T. Plasticity in olfactory bulb circuits. Curr Opin Neurobiol. 2020 Oct; 64: 17–23. DOI: 10.1016/j.conb.2020.01.007. Epub 2020 Feb 13


Review

For citations:


Adamova A.S., Klocheva E.G., Goldobin V.V. The relationship between persistent olfactory dysfunction associated with COVID-19 and olfactory bulb morphology. Medical alphabet. 2025;(15):61-66. (In Russ.) https://doi.org/10.33667/2078-5631-2025-15-61-66

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ISSN 2078-5631 (Print)
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