Acoustic pharyngometry patterns of snoring and obstructive sleep apnea patients

Anatomic narrowing of the pharyngeal airway increases the relative negative pressure generated during inspiration, thus affecting the dynamic behavior of the upper airway. The aim of this work was to measure pharyngeal area in snoring patients with and without obstructive sleep apnea (OSA), as categorized by polysomnography and by acoustic pharyngometry, and to analyze the different curve patterns obtained from patients of both groups.

We examined 50 snorers who were divided into 2 groups matched for age, gender, and body mass index.

Mean Apnea Index (AI) in nonapneic snorers (group 1) was 4, and mean pharyngeal area was 2.41 cm(2). In snoring patients with OSA (group 2), mean AI was 25.9 with a mean pharyngeal area of 1.589 cm(2) (P < 0.001). In both groups, the dependent variable (AI) can be predicted from a linear relation with the independent variable (pharyngeal area) with normality and constant variance tests passed. In group 1, the resulting curve can be 1 of 2 types depending on the relative area of the pharyngeal segment to the velopharyngeal area. In group 2, the curve pattern can be categorized into 3 patterns depending on the possible pathology of pharyngeal obstruction.

The acoustic reflection technique is reproducible, noninvasive, and free from potential side effects. The good correlation between AI and pharyngeal area adds to the potential of acoustic pharyngometry. Careful study of the pharyngeal cross-sectional area and curve topography may give a good idea about the site of upper airway obstruction.