Smell Loss

A research study to assess the baseline olfactory function, mental health status, clinical severity, and immunological profile in patients with smell loss. The impact of a 3-month olfactory training program on smell function, immunological changes, and mental health in patients with smell loss will be evaluated. The primary purpose of this study is to investigate tissue and blood samples to identify molecules that may be related to smell loss, ultimately aiming to develop future treatments for this condition and correlate with cognition.

This research study aims to investigate the function of the olfactory lining in the nasal cavity and its potential alterations in both healthy and diseased conditions. The olfactory lining is involved in the sense of smell. The purpose of this study is to collect tissue from the nasal cavity.

The goal of this clinical trial is to learn if ScentCare, a novel olfactory training device and accompanying companion web-based application, will lead to improved olfactory and well-being outcomes in elderly patients with Olfactory Dysfunction (OD). The main question it aims to answer is: \- What effect does the olfactory training device (ScentCare) and accompanying companion web-based application have on olfaction? Researchers will compare ScentCare to solving Sudoku puzzles to see the effects of olfactory training using this novel device on olfaction. Previous studies have used Sudoku puzzles when studying the effect of smell training. Since smell training is thought to work by stimulating and engaging higher order cognition, Sudoku is a suitable activity for participants in the control group since it serves as a correlate with similar degree of stimulation. Participants will: * Use ScentCare (intervention) or solve Sudoku puzzles (control) twice daily for 3 months. * Visit the clinic twice, once upon enrollment and once three months later. * Complete a formal smell test using Sniffin' Sticks smell test at the beginning of the study and again at the end of the study (3 months) during the initial and follow up visit. * Complete questionnaires at the beginning of the study and again at the end of the study (3 months) during the initial and follow up visit.

* Causes of olfactory dysfunction can be classified into conductive and sensorineural causes. * Conductive causes are mainly due to structural nasal problem, which can be treated by nasal surgery * Sensorineural causes included post-infection, post-head injury, post Head and Neck irradiation and other central nervous system diseases. * Olfactory Training is well established treatment for sensorineural olfactory dysfunction in foreign countries. * Olfactory Training by neurological chemosensory stimulation using aromatic substances delivered via electronic portable aromatic rehabilitation (EPAR) diffuser was proved to be effective treatment in COVID-19 related olfactory dysfunction in recent Hong Kong study. * However, there is a lack of local study on the effect of Olfactory Training in other non-COVID-19 sensorineural causes of olfactory dysfunction in Hong Kong population.

The goal of this observational study is to learn what can predict the return of the sense of smell in patients with chronic rhinosinusitis with nasal polyps being treated with dupilumab. The main questions it aims to answer are: 1. Does obstruction of the olfactory cleft predict return of the sense of smell? 2. Do electrophysiological signals generated by breathing and sniffing behavior predict return of the sense of smell? Participants starting dupilumab will undergo assessment for their degree of olfactory cleft obstruction, and an electrophysiologic assessment of their olfactory cleft and be followed over 6 months of treatment with dupilumab.