Laryngeal and pharyngeal activity during semioccluded vocal tract postures in subjects diagnosed with hyperfunctional dysphonia

Abstract

High vertical laryngeal position (VLP), pharyngeal constriction, and laryngeal compression are common features associated with hyperfunctional voice disorders. The present study aimed to observe the effect on these variables of different semioccluded vocal tract postures in 20 subjects diagnosed with hyperfunctional dysphonia. During observation with flexible endoscope, each participant was asked to produce eight different semioccluded exercises: lip trills, hand-over-mouth technique, phonation into four different tubes, and tube phonation into water using two different depth levels. Participants were required to produce each exercise at three loudness levels: habitual, soft, and loud. To determine the VLP, anterior-to-posterior (A-P) compression, and pharyngeal width, a human evaluation test with three blinded laryngologists was conducted. Judges rated the three endoscopic variables using a five-point Likert scale. An intraclass correlation coefficient to assess intrarater and interrater agreement was performed. A multivariate linear regression model considering VLP, pharyngeal width, and A-P laryngeal compression as outcomes and phonatory tasks and intensity levels as predictive variables were carried out. Correlation analysis between variables was also conducted. Results indicate that all variables differ significantly. Therefore, VLP, A-P constriction, and pharyngeal width changed differently throughout the eight semioccluded postures. All semioccluded techniques produced a lower VLP, narrower aryepiglottic opening, and a wider pharynx than resting position. More prominent changes were obtained with a tube into the water and narrow tube into the air. VLP significantly correlated with pharyngeal width and A-P laryngeal compression. Moreover, pharyngeal width significantly correlated with A-P laryngeal compression.

Keywords: Aryepiglottic narrowing; Dysphonia; Hyperfunction; Pharyngeal width; Semiocclusion; Vertical laryngeal position; Vocal tract; Voice therapy.