{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,9]],"date-time":"2026-09-09T06:26:38Z","timestamp":1788935198763,"version":"build-2803163510"},"reference-count":40,"publisher":"Wiley","issue":"12","license":[{"start":{"date-parts":[[2025,5,15]],"date-time":"2025-05-15T00:00:00Z","timestamp":1747267200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["The Laryngoscope"],"published-print":{"date-parts":[[2025,12]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>Olfactory training is a recommended treatment in patients with olfactory dysfunction after COVID\u201019. However, the effectiveness of olfactory training in COVID\u201019\u2010induced olfactory dysfunction has been studied; only a few studies have included a placebo group to compare the effect of traditional olfactory training with odor\u2010free olfactory training. In this randomized placebo\u2010controlled trial, we evaluate the effect of olfactory training with essential oils versus olfactory training with placebo oils in patients with post\u2010COVID\u201019 olfactory dysfunction.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      Sixty\u2010five patients with COVID\u201019 induced olfactory dysfunction were randomized to the intervention or control group. Patients in the intervention group performed classic olfactory training with four essential oils (orange, lavender, clove, and peppermint) twice daily for 12\u2009weeks, while the control group performed the same olfactory training but with odor\u2010free placebo oils. Olfactory function was assessed using the Sniffin Sticks extended\n                      <jats:italic>TDI<\/jats:italic>\n                      test at baseline and at follow\u2010up after the 12\u2010week intervention.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The intervention group did not significantly improve their olfactory function compared to the control group after olfactory training. Additionally, no associations were found between changes in olfactory function after olfactory training and age, gender, rhinitis, time since infection, or pre\u2010infection vaccine. A regression analysis showed that the presence of parosmia was associated with reduced effectiveness of olfactory training.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>This study found that 12\u2009weeks of classical olfactory training is not effective in the treatment of COVID\u201019 induced olfactory dysfunction. Moreover, the study indicates that parosmia reduces the effect of olfactory training significantly.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Level of Evidence<\/jats:title>\n                    <jats:p>2.<\/jats:p>\n                    <jats:p>\n                      <jats:bold>Trial Registration:<\/jats:bold>\n                      <jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"http:\/\/clinicaltrials.gov\">Clinicaltrials.gov<\/jats:ext-link>\n                      registration number: NCT05539560\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/lary.32275","type":"journal-article","created":{"date-parts":[[2025,5,15]],"date-time":"2025-05-15T08:33:42Z","timestamp":1747298022000},"page":"4849-4857","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Effect of Olfactory Training in\n                    <scp>COVID<\/scp>\n                    \u201019 Related Olfactory Dysfunction\u2014A Placebo\u2010Controlled Trial"],"prefix":"10.1002","volume":"135","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6521-2555","authenticated-orcid":false,"given":"Ditte Gertz","family":"Mogensen","sequence":"first","affiliation":[{"name":"Department of Otorhinolaryngology, Head and Neck Surgery &amp; Audiology Copenhagen University Hospital, Rigshospitalet  Copenhagen Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7353-0817","authenticated-orcid":false,"given":"Kasper","family":"Aanaes","sequence":"additional","affiliation":[{"name":"Department of Otorhinolaryngology, Head and Neck Surgery &amp; Audiology Copenhagen University Hospital, Rigshospitalet  Copenhagen Denmark"},{"name":"Department of Clinical Medicine, Faculty of Health and Medical Sciences Copenhagen University  Copenhagen Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ida Brandt","family":"Andersen","sequence":"additional","affiliation":[{"name":"Department of Otorhinolaryngology, Head and Neck Surgery &amp; Audiology Copenhagen University Hospital, Rigshospitalet  Copenhagen Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3040-8384","authenticated-orcid":false,"given":"Mary","family":"Jarden","sequence":"additional","affiliation":[{"name":"Department of Clinical Medicine, Faculty of Health and Medical Sciences Copenhagen University  Copenhagen Denmark"},{"name":"Department of Hematology, Center for Cancer and Organ Diseases Copenhagen University Hospital, Rigshospitalet  Copenhagen Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7806-7219","authenticated-orcid":false,"given":"Vibeke","family":"Backer","sequence":"additional","affiliation":[{"name":"Department of Otorhinolaryngology, Head and Neck Surgery &amp; Audiology Copenhagen University Hospital, Rigshospitalet  Copenhagen Denmark"},{"name":"Department of Clinical Medicine, Faculty of Health and Medical Sciences Copenhagen University  Copenhagen Denmark"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2025,5,15]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.7326\/M20\u20102428"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.1002\/lary.30453"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1111\/joim.13564"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1159\/000525861"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.1007\/s40629\u2010022\u201000216\u20107"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.tins.2022.11.003"},{"key":"e_1_2_8_8_1","doi-asserted-by":"publisher","DOI":"10.3389\/fpsyg.2023.1165911"},{"key":"e_1_2_8_9_1","doi-asserted-by":"publisher","DOI":"10.1159\/000523893"},{"key":"e_1_2_8_10_1","doi-asserted-by":"publisher","DOI":"10.4193\/Rhino16.248"},{"key":"e_1_2_8_11_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.neubiorev.2022.104853"},{"key":"e_1_2_8_12_1","doi-asserted-by":"publisher","DOI":"10.1002\/lio2.62"},{"key":"e_1_2_8_13_1","doi-asserted-by":"publisher","DOI":"10.1002\/lary.24340"},{"key":"e_1_2_8_14_1","doi-asserted-by":"publisher","DOI":"10.1002\/lary.25245"},{"key":"e_1_2_8_15_1","doi-asserted-by":"publisher","DOI":"10.4193\/Rhino15.264"},{"key":"e_1_2_8_16_1","doi-asserted-by":"publisher","DOI":"10.1002\/lary.30101"},{"key":"e_1_2_8_17_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00405\u2010022\u201007570\u2010w"},{"key":"e_1_2_8_18_1","doi-asserted-by":"publisher","DOI":"10.1159\/000528188"},{"key":"e_1_2_8_19_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00405\u2010006\u20100173\u20100"},{"key":"e_1_2_8_20_1","doi-asserted-by":"publisher","DOI":"10.1093\/chemse\/22.1.39"},{"key":"e_1_2_8_21_1","doi-asserted-by":"publisher","DOI":"10.1002\/lary.27052"},{"key":"e_1_2_8_22_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00405\u2010018\u20105248\u20101"},{"key":"e_1_2_8_23_1","doi-asserted-by":"publisher","DOI":"10.1097\/01.mlg.0000234915.51189.cb"},{"key":"e_1_2_8_24_1","doi-asserted-by":"publisher","DOI":"10.1002\/lary.20101"},{"key":"e_1_2_8_25_1","volume-title":"Der 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