Olfactory Function in Patients With Obstructive Sleep Apnea Using Positive Airway Pressure.

Previous studies reported that positive airway pressure (PAP) treatment may improve olfaction function in patients with obstructive sleep apnea (OSA) through various mechanisms. Olfactory function before and after PAP treatment is understudied regarding patient group at issue. The aim of this study is to investigate the contribution of PAP to olfactory function in patients with OSA. The study was conducted on 26 patients with OSA (10 females and 16 males, mean age 50.1 [9.3] years) who scheduled for PAP treatment. The Connecticut Chemosensory Clinical Research Center odor test was performed before and 4 months after PAP treatment. Patients were grouped (normal, anosmia, mild hyposmia, moderate hyposmia, and severe hyposmia) with respect to olfactory function by measuring odor test parameters, including threshold determination and identification. The odor test average scores of the patients after 4-month PAP treatment compared to pretreatment scores were increased and the difference was statistically significant (P = .002). In the apnea hypopnea index groups, statistically significant difference was found in the threshold and discrimination values regarding before PAP treatment (P = .038, P = .022, respectively). This study revealed that improvement in olfactory thresholds in patients with OSA receiving PAP treatment seems to improve olfactory dysfunction. This provides minimization of OSA consequences, including progressive upper airway inflammation, cognitive impairment, and associated olfactory dysfunction. Resolving the associations between olfactory function and PAP treatment is an important area for future research.