Smell training
Smell training or olfactory training is the act of regularly sniffing or exposing oneself to robust aromas[1] with the intention of regaining a sense of smell. The stimulating smells used are often selected from major smell categories, such as aromatic, flowery, fruity, and resinous.[1] Using strong scents, the patient is asked to sniff each different smell for a minimum of 20 seconds, no less than two times per day, for three to six months or more.[2][3] It is used as a rehabilitative therapy to help people who have anosmia or post-viral olfactory dysfunction, a symptom of COVID-19.[4] It was considered a promising experimental treatment in a 2017 meta-analysis.[1]
Efficacy
Along with olfactory implants,[5] smell training is a promising but experimental treatment option.[1]
Several individual studies have indicated that smell training can increase olfactory sensitivity.[6][7][8] In 2021 a meta-analysis was published that examined research studies of olfactory training for treating loss of smell as a consequence of a viral infection. It found clinically significant improvements and supported its use as a treatment option.[9] As of March 2021, there have been no studies of smell training's efficacy for children.[10]
In 2017, the International and European Rhinologic Societies recommended smell training for treating loss of smell due to various conditions.[11] In 2020, the British Rhinological Society published consensus guidelines for the treatment of smell loss due to COVID-19.[12] Although no specific studies were available at that time, the expert panel made recommendations regarding treatment options and concluded that "olfactory training was recommended for all [COVID-19] patients with persistent loss of sense of smell of more than 2 weeks duration."[12]
Critics such as
Mechanism
Smell training likely achieves results because the olfactory nerve and olfactory bulb have neural plasticity and are able to regenerate.[1]
History
The idea was first written about by Thomas Hummel, a German psychologist at the
Hummel's paper built on a 1989 study by the Monell Chemical Senses Center in Philadelphia. The study showed that after repeated exposure to androstenone, a chemical which half of all humans cannot detect, some subjects gained the ability to smell it.[16]
Alternatives
In addition to smell training, other treatments for anosmia that have been researched include
References
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- ^ Olfactory dysfunction in COVID-19: diagnosis and management. Whitcroft KL, Hummel T. JAMA. 2020;323:2512–2514. [Abstract] [Google Scholar]
- ^ Chabot A, Huntwork M. Turmeric as a Possible Treatment for COVID-19-Induced Anosmia and Ageusia Cureus. ;13(9). PMCID: PMC8502749.
- PMID 33663108.
- S2CID 207904053.
- PMID 32248300.
- ^ S2CID 5239574.
- PMID 33210732.
- S2CID 220519030.
- ^ Rodriguez CH (25 March 2021). "Nosing In on Kids Who Had Covid and Lost Their Sense of Smell". Kaiser Health News. Retrieved 25 March 2021.
- PMID 29528615. Retrieved 5 May 2021.
- ^ PMID 32854169.
- S2CID 204330823.
- ^ Gamble M. "People Are Trying a Questionable Therapy to Get Back Their Sense of Smell". Slate. Retrieved 5 May 2021.
- ^ Shapouri B (17 November 2020). "The Weird World of Olfactory Training". Allure. Retrieved 30 March 2021.
- PMID 2813372.
- PMID 32567798.
Further reading
- Michael Barbaro (23 March 2021). "A Food Critic Loses Her Sense of Smell". The Daily (Podcast). The New York Times. Retrieved 24 March 2021.
- Collins C (4 February 2021). COVID-19 patients and 'smell training' (Video). The Los Angeles Times.