Acoustic analysis of snoring and the site of airway obstruction in sleep related respiratory disorders.

Seventy-five adult patients with sleep related respiratory disorders were examined by polysomnography with simultaneous recordings of the intraluminal pressure of the upper airway and snoring sound. Obstructed sites in the upper airway during sleep were determined by comparing the amplitude of respiratory fluctuation of the pressures in the epipharynx, mesopharynx, hypopharynx and esophagus. A definite correlation existed between the intensity of snoring sound and the amplitude of respiratory fluctuation of the intraesophageal pressure. Based on the results of the intraluminal pressure partitioning, the subjects were divided into the soft palate type (28), the tonsil/tongue base type (14), the combined type (27) and the larynx type (6). The average value of fundamental frequency (ff) was 102.8+/-34.9 Hz in the soft palate type, 331.7+/-144.8 Hz in the tonsil tongue base type, 115.7+/-58.9 Hz in the combined type and around 250 Hz in the larynx type.