The human sense of smell

Abstract

The sense of smell, like taste and trigeminal senses, is a chemical sense dedicated to the perception of chemical stimulations and to the generation of responses to them. Although, from an evolutionary perspective, the chemical senses are the oldest of our senses, our knowledge on the neural processing of the three chemical senses is still incomplete and has been considerably lagging behind that of our other senses. The current review aims to give an overview about human smell function. In particular we focus on the anatomy and physiology of the olfactory system, the epidemiology and the causes of olfactory loss, and on the clinical management of olfactory disorders stressing the impact of smell loss on the quality of life. Lastly, we emphasize the importance of olfaction in every day life. In our opinion, the impairment of sense of smell should be taken into serious consideration by the clinicians, as it could be the indicator of important systemic diseases or the cause of domestic accidents.

Ultramicronized Palmitoylethanolamide and Luteolin Supplement Combined with Olfactory Training to Treat Post-COVID-19 Olfactory Impairment: A Multi-Center Double-Blinded Randomized Placebo- Controlled Clinical Trial

“…Several therapies, including administration of oral or topical corticosteroids, phosphodiesterase inhibitors, intranasal calcium buffers, and other treatments, are under study, but evidence of benefit is thus far insufficient to guide clinical care [ 11 ]. Treatments generally target COVID-19 smell impairment arising from either peripheral damage (injury to nasal neuroepithelium), central inflammation (injury to olfactory bulbs or higher olfactory centers), or both [ 29 ]. In this trial, individuals receiving PEA-LUT during olfactory training had a significantly higher likelihood of recovering olfactory function than those receiving placebo; an increase in TDI score was observed in 92.2 percent of those receiving PEA-LUT versus only 42 percent of those receiving placebo, with significantly lower rates of residual anosmia in the PEA-LUT group.…”

“…The sample size was calculated as indicated by Wang and Ji [ 29 ] and it was specific for Randomized Clinical Trial. The calculation was performed on the https://riskcalc.org .…”