Olfactory training outcomes in post COVID 19 olfactory dysfunction


  • Mohammed Abdulwahab Bahjat Kirkuk Health Directorate, Ministry of Health, Kirkuk, Iraq.
  • Raad Darweesh Fadhil Kirkuk Health Directorate, Ministry of Health, Kirkuk, Iraq.
  • Usama Zidan Khalaf Kirkuk Health Directorate, Ministry of Health, Kirkuk, Iraq.




Olfactory training, outcomes, COVID-19, olfactory dysfunction


Objectives: The aim of study is to evaluate the olfaction recovery of patients who performed OT (olfactory training) in a post-COVID-19 PPVOD.

Methods: Study included 50 patients with a sudden loss of smell and a confirmed COVID-19 diagnosis from January 2020 to January 2021 in Kirkuk General Hospital. These participants were submitted to The Sniffin’ Sticks test in order to identify those with persistent olfactory dysfunction who were treated either by olfactory training combined with a 10-day course of oral corticosteroids, or by olfactory training alone.

Results: Cross sectional comparative study for 50 patients have history of COVID 19 infection, mean age of patients [47 ± 10] years. [56%] of patients at age group ≥ 45 years, [44%] of patients are females and [56%] are males. The mean of TDI score increase after OT than before OT with significant difference.

Conclusion: Olfactory function appeared to improve only in peripheral aspects of post COVID-19 PPVOD after OT. patients < 45 years have high mean of TDI score than patients ≥ 45 years old.


Riestra-Ayora, J.; Yanes-Diaz, J.; Esteban-Sanchez, J.; Vaduva, C.; Molina-Quiros, C.; Larran-Jimenez, A.; Martin-Sanz, E. Long Term Follow-up of Olfactory and Gustatory Dysfunction in COVID-19: 6 Months Case—Control Study of Health Workers. Eur. Arch. Oto-Rhino-Laryngol. 2021, 278, 4831–4837. [CrossRef] [PubMed]

Lucidi, D.; Molinari, G.; Silvestri, M.; De Corso, E.; Guaraldi, G.; Mussini, C.; Presutti, L.; Fernandez, I.J. Patient-Reported Olfactory Recovery after SARS-CoV-2 Infection: A 6-Month Follow-Up Study. Int. Forum Allergy Rhinol. 2021, 11, 1249–1252. [CrossRef] [PubMed]

Hopkins, C.; Surda, P.; Vaira, L.A.; Lechien, J.R.; Safarian, M.; Saussez, S.; Kumar, N. Six Month Follow-Up of Self-Reported Loss of Smell during the COVID-19 Pandemic. Rhinol. J. 2021, 59, 26–31. [CrossRef]

Boscolo-Rizzo, P.; Guida, F.; Polesel, J.; Marcuzzo, A.V.; Antonucci, P.; Capriotti, V.; Sacchet, E.; Cragnolini, F.; D’Alessandro, A.; Zanelli, E.; et al. Self-Reported Smell and Taste Recovery in Coronavirus Disease 2019 Patients: A One-Year Prospective Study. Eur. Arch. Oto-Rhino-Laryngol. 2022, 279, 515–520. [CrossRef]

Lechien, J.R.; Chiesa-Estomba, C.M.; Beckers, E.; Mustin, V.; Ducarme, M.; Journe, F.; Marchant, A.; Jouffe, L.; Barillari, M.R.; Cammaroto, G.; et al. Prevalence and 6-Month Recovery of Olfactory Dysfunction: A Multicentre Study of 1363 COVID-19 Patients. J. Intern. Med. 2021, 290, 451–461. [CrossRef] [PubMed]

Petrocelli, M.; Cutrupi, S.; Salzano, G.; Maglitto, F.; Salzano, F.A.; Lechien, J.R.; Saussez, S.; Boscolo-Rizzo, P.; De Riu, G.; Vaira, L.A. Six-Month Smell and Taste Recovery Rates in Coronavirus Disease 2019 Patients: A Prospective Psychophysical Study. J. Laryngol. Otol. 2021, 135, 436–441. [CrossRef] [PubMed]

Arnaud, T.; Evelina, T.; Mats, J.O.; Nina, G.-N.; Sebastian, H.; Charlotte, T.; Johan, N.L. High Prevalence of Olfactory Disorders 18 Months after Contracting COVID-19. medRxiv 2022. [CrossRef]

Vandersteen, C.; Payne, M.; Dumas, L.-E.; Metelkina-Fernandez, V.; Plonka, A.; Chirio, D.; Demonchy, E.; Risso, K.; Askenazy-Gittard, F.; Guevara, N.; et al. Persistent Olfactory Complaints after COVID-19: A New Interpretation of the Psychophysical Olfactory Scores. Rhinol. Online 2021, 4, 66–72. [CrossRef]

Aschenbrenner, K.; Hummel, C.; Teszmer, K.; Krone, F.; Ishimaru, T.; Seo, H.-S.; Hummel, T. The Influence of Olfactory Loss on Dietary Behaviors. Laryngoscope 2008, 118, 135–144. [CrossRef]

Valsamidis, K.; Printza, A.; Constantinidis, J.; Triaridis, S. The Impact of Olfactory Dysfunction on the Psychological Status and Quality of Life of Patients with Nasal Obstruction and Septal Deviation. Int. Arch. Otorhinolaryngol. 2020, 24, e237–e246. [CrossRef]

Mazzatenta A, Neri G, D'Ardes D, De Luca C, Marinari S, Porreca E, Cipollone F, Vecchiet J, Falcicchia C, Panichi V, Origlia N, Di Giulio C. Smell and Taste in Severe CoViD-19: Self-Reported vs. Testing. Front Med (Lausanne). 2020 Dec 2;7:589409.

Delgado-Losada ML, Delgado-Lima AH, Bouhaben J. Spanish Validation for Olfactory Function Testing Using the Sniffin' Sticks Olfactory Test: Threshold, Discrimination, and Identification. Brain Sci. 2020;10(12):943.

Whitcroft KL, Hummel T. Olfactory Dysfunction in COVID-19: Diagnosis and Management. JAMA. 2020;323(24):2512–2514.

Oleszkiewicz A, Schriever VA, Croy I, Hähner A, Hummel T. Updated Sniffin' Sticks normative data based on an extended sample of 9139 subjects. Eur Arch Otorhinolaryngol. 2019 Mar;276(3):719-728.

Karamali K, Elliott M, Hopkins C. COVID-19 related olfactory dysfunction. Curr Opin Otolaryngol Head Neck Surg. 2022 Feb 1;30(1):19-25.

Wu TJ, Yu AC, Lee JT. Management of post-COVID-19 olfactory dysfunction. Curr Treat Options Allergy. 2022;9(1):1-18.

Webster KE, O'Byrne L, MacKeith S, Philpott C, Hopkins C, Burton MJ. Interventions for the prevention of persistent post-COVID-19 olfactory dysfunction. Cochrane Database Syst Rev. 2021;7(7):CD013877.

Hummel, T.; Rissom, K.; Reden, J.; Hähner, A.; Weidenbecher, M.; Hüttenbrink, K.-B. Effects of Olfactory Training in Patients with Olfactory Loss. Laryngoscope 2009, 119, 496–499.

Bordin, A.; Mucignat-Caretta, C.; Gaudioso, P.; Pendolino, A.L.; Leoni, D.; Scarpa, B.; Andrews, P.J.; Cattelan, A.M.; Antonini, A.; Nicolai, P.; et al. Comparison of Self-reported Symptoms and Psychophysical Tests in Coronavirus Disease 2019 (COVID-19) Subjects Experiencing Long-Term Olfactory Dysfunction: A 6-Month Follow-Up Study. Int. Forum Allergy Rhinol. 2021, 11, 1592–1595. [CrossRef]

Niklassen, A.S.; Draf, J.; Huart, C.; Hintschich, C.; Bocksberger, S.; Trecca, E.M.C.; Klimek, L.; Le Bon, S.D.; Altundag, A.; Hummel, T. COVID-19: Recovery from Chemosensory Dysfunction. A Multicentre Study on Smell and Taste. Laryngoscope 2021, 131, 1095–1100. [CrossRef]

Iannuzzi, L.; Salzo, A.E.; Angarano, G.; Palmieri, V.O.; Portincasa, P.; Saracino, A.; Gelardi, M.; Dibattista, M.; Quaranta, N. Gaining Back What Is Lost: Recovering the Sense of Smell in Mild to Moderate Patients after COVID-19. Chem. Senses 2020, 45, 875–881. [CrossRef] [PubMed].

Jafar, A.; Lasso, A.; Shorr, R.; Hutton, B.; Kilty, S. Olfactory Recovery Following Infection with COVID-19: A Systematic Review. PLoS ONE 2021, 16, e0259321. [CrossRef] [PubMed].

de Melo, G.D.; Lazarini, F.; Levallois, S.; Hautefort, C.; Michel, V.; Larrous, F.; Verillaud, B.; Aparicio, C.; Wagner, S.; Gheusi, G.; et al. COVID-19–Related Anosmia Is Associated with Viral Persistence and Inflammation in Human Olfactory Epithelium and Brain Infection in Hamsters. Sci. Transl. Med. 2021, 13, eabf8396. [CrossRef] [PubMed].

Vaira, L.A.; Salzano, G.; Le Bon, S.D.; Maglio, A.; Petrocelli, M.; Steffens, Y.; Ligas, E.; Maglitto, F.; Lechien, J.R.; Saussez, S.; et al. Prevalence of Persistent Olfactory Disorders in Patients with COVID-19: A Psychophysical Case-Control Study with 1-Year Follow-Up. Otolaryngol. Neck Surg. 2021, 23, 019459982110615.

Saussez, S.; Vaira, L.A.; Chiesa-Estomba, C.M.; Le Bon, S.D.; Horoi, M.; Deiana, G.; Petrocelli, M.; Boelpaep, P.; Salzano, G.; Khalife, M.; et al. Short-Term Efficacy and Safety of Oral and Nasal Corticosteroids in COVID-19 Patients with Olfactory Dysfunction: A European Multicenter Study. Pathogens 2021, 10, 698.

Hummel, T.; Whitcroft, K.L.; Andrews, P.; Altundag, A.; Cinghi, C.; Costanzo, R.M.; Damm, M.; Frasnelli, J.; Gudziol, H.; Gupta, N.; et al. Position Paper on Olfactory Dysfunction. Rhinol. J. 2017, 54, 1–30.

Oleszkiewicz, A.; Hanf, S.; Whitcroft, K.L.; Haehner, A.; Hummel, T. Examination of Olfactory Training Effectiveness in Relation to Its Complexity and the Cause of Olfactory Loss. Laryngoscope 2018, 128, 1518–1522.

Ojha, P.; Dixit, A. Olfactory Training for Olfactory Dysfunction in COVID-19: A Promising Mitigation amidst Looming Neurocognitive Sequelae of the Pandemic. Clin. Exp. Pharmacol. Physiol. 2022, 49, 462–473. [CrossRef] [PubMed].

Hummel, T.; Stupka, G.; Haehner, A.; Poletti, S.C. Olfactory Training Changes Electrophysiological Responses at the Level of the Olfactory Epithelium. Rhinology 2018, 56, 330–335.

Kollndorfer, K.; Fischmeister, F.P.S.; Kowalczyk, K.; Hoche, E.; Mueller, C.A.; Trattnig, S.; Schöpf, V. Olfactory Training Induces Changes in Regional Functional Connectivity in Patients with Long-Term Smell Loss. NeuroImage Clin. 2015, 9, 401–410.

McAlpine, L.S.; Fesharaki-Zadeh, A.; Spudich, S. Coronavirus Disease 2019 and Neurodegenerative Disease: What Will the Future Bring? Curr. Opin. Psychiatry 2021, 34, 177–185.




How to Cite

Bahjat, M. A. ., Fadhil, R. D. ., & Khalaf, U. Z. . (2022). Olfactory training outcomes in post COVID 19 olfactory dysfunction. Iraq Medical Journal, 6(3). https://doi.org/10.22317/imj.v6i3.1197