is metallic perception a taste, an aroma or a flavor ?
Aim Metallic taste is known to vanish with nasal occlusion, suggesting it should be termed metallic “aroma” rather than metallic “taste.” However, it also appears after neurological injuries, such as a chorda tympani section, which suppresses taste perception mediated by the facial nerve. Methods In 120 healthy volunteers, the perception of an iron sulfate solution was assessed at different lingual locations—corresponding to the facial and glossopharyngeal nerves—and with either open (n=60) or closed (n=60) noses to evaluate if it is a taste or an aroma. Results Nasal occlusion significantly reduced the perception of iron sulfate. It prevented perception in 31.7% of participants, though it did not completely eliminate it in the remaining 68.3%. Additionally, in open-nosed subjects, the intensity of iron sulfate perception was significantly greater when applied to the base of the tongue (glossopharyngeal nerve) than to the tip (facial nerve). These differences did not persist with nasal occlusion. Conclusion Nasal occlusion diminished but did not abolish the perception of iron sulfate. With an open nose, a differential taste perception was significant, but not with a closed nose. Therefore, metallic perception involves both retro-olfactory and gustatory components, suggesting it is a metallic flavor. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was funded by 'la Ligue contre le Cancer' ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: CPP Est IV on 16/12/2021 (no. 2021-A02149-32) for the open nose and on 05/08/2022 (no. 2022-A01475-38) for the occluded nose I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors
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