A comparison between recording sites of snoring sounds in relation to upper airway obstruction.

This paper presents the results of our study on investigating the acoustical properties of snoring sounds (SS) recorded by two microphones (one over trachea and one hung in the air within 30-50 cm away from the subject) in relation to sleep apnea. Several features were extracted from SS segments of 50 snorers with different Apnea-Hypopnea Index (AHI). We used an optimal subset of the sound features to cluster the SS segments into two clusters (A and B). Then, the number of SS segments in cluster A was calculated and normalized by the total number of SS segments for each subject, resulting in 50 × 1 vector R. A correlation analysis was run between AHI and R. The results show a difference in acoustical properties of the tracheal and ambient snoring sounds and their ability to distinguish two types of snoring; the ambient snoring sounds are not as characteristic as tracheal snoring sounds.