The Smell and Taste Corner: The Human Chemical Senses Are Useless, Are They Not?

Abstract

Questioned about human senses, most people would spontaneously name vision, hearing, touch, and maybe smell. In contrast, taste is often forgotten, let alone the trigeminal sensitivity, and only few people are aware of the vestibular senses we have. So, in a way, people indicate that the chemical senses are useless. We would like to maintain that they are not – loss of olfactory function is associated with loss of flavor, social competence, and depression [1]. With the exception of sight, all these senses are, not exclusively, but widely located in the area of otolaryngologists. During the specialty training, we spend huge efforts on acquiring surgical skills and management of diseases but often forget that we do work on sensory organs, and too little attention is paid to the physiologic comprehension of these systems. With this upcoming series of articles labeled as “Smell and Taste Corner,” we would like to focus on the human chemical senses. Humans have at least three systems that enable them to perceive aqueous or volatile molecules to be sensed. Olfaction, located in the nose, and taste in the oropharyngeal cavity, are probably familiar to most specialists. However, the third chemical sense, the trigeminal system, represents the touch/tactile and chemo-somatosensory system of the oral and nasal mucosa and is less known. Clinically underexplored, it is probably a major player in maintaining normal nasal and oral perception, with dysfunctions being very disabling, probably involved in empty nose [2] or burning mouth syndrome. The field of chemical senses has also seen a tremendous evolution since it became clear that olfactory disorders precede many neurodegenerative disorders, opening a door to potential early, inexpensive, and easily accessible screening for such diseases [3]. Very recent contributions further suggest that olfactory function is highly trainable in health and disease [4], and that good olfactory function seems to be a reliable predictor for overall health and is inversely associated to mortality in the elderly population [5]. Consequently, smell and taste that are intimately related to otolaryngology because precise examination and testing has Received: July 5, 2019 Accepted: July 8, 2019 Published online: July 16, 2019