The relationships between the clinical and polysomnographic findings and the olfactory function in patients with obstructive sleep apnea syndrome

Abstract

Purpose This study aimed to investigate the relationships between the clinical and polysomnographic findings and the olfactory test results in patients with obstructive sleep apnea syndrome (OSAS). Four groups were established: non-snoring controls (group 1), non-apneic snorers (group 2), mild-moderate OSAS (group 3), and severe OSAS (group 4). The polysomnographic findings, otorhinolaryngologic findings, Epworth Sleepiness Scale (ESS), and Sniffin' Sticks olfactory test results of the four groups were compared. The relationships between the clinical data and the olfactory parameters were evaluated. Group 4 had the worst odor identification and discrimination scores. Non-apneic snorers also had worse odor parameters compared with the non-snorer controls. A significant negative correlation was found among the ESS, apnea-hypopnea index (AHI), mean arterial oxygen saturation, and odor identification and discrimination. Significant negative correlations were found between the tongue and tongue base sizes and among all olfactory parameters. Our study revealed olfactory dysfunction in patients with OSAS. A strong negative correlation between the olfactory parameters and the severity of sleep apnea was also found. Olfactory tests may be used to predict the presence and severity of OSAS in the future.