Olfactory Impairment

This is a prospective, observational study examining the impact of highly effective cystic fibrosis transmembrane conductance regulator (CFTR) modulators on chronic rhinosinusitis (CRS) and olfactory dysfunction (OD) in young children with cystic fibrosis (YCwCF). This study involves two groups: children 2-8 years old, inclusive at initial visit, receiving highly effective modulator therapy (HEMT), and a control group of children 2-8 years old, inclusive at initial visit, not receiving HEMT. Outcomes will include sinus magnetic resonance imaging (MRI) scans, olfactory tests, and quality of life surveys obtained over a two-year period.

* 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.