Khalid A. Alyahya

COVID-19 is associated with a common symptom of olfactory dysfunction, which may persist even after the infection is resolved. Olfactory training (OT) has emerged as the most effective intervention for post-viral olfactory dysfunction. OT involves daily exposure of the olfactory system to various odors. The current study aims to explore olfactory dysfunction following COVID-19 and the potential benefits of olfactory training. Methods: This is a cross-sectional study conducted among adults aged 18–60 living in Alahssa, Saudi Arabia. An online questionnaire containing an informed consent form and a survey to collect demographic data, vaccination status, level of loss of smell and taste, and the level of awareness about olfactory training (OT) was distributed among all participants who agreed to participate in this study. Results: The study included 524 participants and presented their baseline characteristics, including age, gender, COVID-19 infection status, and complaints. Most patients were female (66.0%), and 46.2% had previously been infected with COVID-19. About 54.8% of participants reported chemosensory dysfunction, while 286 had olfactory dysfunction. Of those, 29.8% had anosmia, 16.8% had hyposmia, and 8.0% had parosmia. Results suggest that being fully or partially vaccinated may offer some protection against olfactory dysfunction compared to being unvaccinated. Adherence to olfactory training was associated with improvement in the sense of smell. Conclusions: The study highlights the importance of awareness and adherence to olfactory training, which may improve the sense of smell in individuals with chemosensory dysfunction. The findings of this study can inform public health policies and interventions aimed at reducing the burden of olfactory dysfunction associated with COVID-19 vaccination.

Objectives This study is aimed to investigate the differences in the clinical features and surgical outcomes between hypopnea‐ and apnea‐predominant obstructive sleep apnea (OSA). Design Cohort study. Setting Single tertiary care centre. Participants This study included 190 patients with OSA who underwent multilevel upper airway surgery between September 2012 and September 2021. The patients were divided into two groups according to the proportion of each respiratory event: hypopnea‐predominant ( n = 102) and apnea‐predominant ( n = 88). Main Outcome Measures The primary outcome measure was the percentage improvement in the apnea‐hypopnea index (AHI) from baseline AHI after surgery. Results The apnea‐predominant group included more male patients and had higher AHI, respiratory disturbance index (RDI) and oxygen desaturation index (ODI) than the hypopnea‐predominant group. Both groups showed significant improvements in AHI, apnea index, RDI, supine AHI, REM AHI, non‐REM AHI, ODI, lowest O 2 saturation and Epworth Sleepiness Scale scores following the surgery. Notably, hypopnea index increased after surgery in the apnea‐predominant OSA group. Although the improvement in the absolute value of AHI by surgery was significantly greater in the apnea‐predominant group than in the hypopnea‐predominant group, the two groups showed no significant difference in the percentage improvement in AHI from baseline AHI. Conclusion Patients with apnea‐predominant OSA had more severe disease than those with hypopnea‐predominant OSA; however, surgical outcomes, as evaluated by percentage AHI improvement, were comparable between the two groups. In addition, multilevel upper airway surgery may induce the transition from apnea to hypopnea in patients with apnea‐predominant OSA.