**1. Introduction**

Our sensory systems are continuously exposed to external stimuli that are processed in the neural pathways of the nervous system in order to maintain bodily homeostasis and to provide appropriate behavioral responses. While some of our senses are more readily recognized for their role in guiding our daily lives and routine behaviors, such as vision and hearing, other senses are noticed primarily when they fail to work or are impaired during disease. This is the case for our chemical senses, taste and smell [1]. Recent estimates suggest that more than 12% of the U.S. population experiences taste or smell (chemosensory) dysfunction [2, 3]. Therefore, it is critical to identify treatments for smell and taste disorders [4]. Olfaction is increasingly acknowledged for its predictive value as an indicator of disorders. Olfactory deficits are evident early on in certain disorders such as Alzheimer's Disease and Parkinson's Disease. More generally, olfactory dysfunction is found in diseases that cause degenerative neuropathology, progressive loss of memory and communication function, normal age-based decline of physiological functions, intellectual challenges, depressive and anxiety disorders, as well as post-traumatic stress disorders. The relevance of olfaction as a predictor of disease has come to the forefront during the Covid-19 pandemic. Many Covid-19 patients experience smell and taste dysfunctions that are not related to blockage of nasal passages as seen in the upper respiratory tract infections [5–8].
