Phonation With a Variably Occluded Facemask: Effects of Task Duration

Abstract

Objective: Semioccluded vocal tract (SOVT) exercises are routinely included in many voice therapy programs because they have been shown to improve acoustic, aerodynamic, and patient-reported voice outcomes. One limitation of the traditional SOVT exercise is that the nature of phonation through straws or semioccluded oral postures allows only for single phoneme production. A variably occluded facemask (VOFM) allows for use of articulated connected speech beyond the production of single phonemes, while still providing occlusion and, presumably, the vocal efficiency benefits that arise from it. This study reports on the effect of time duration of phonation with a variably occluded facemask on voice outcomes in patients with voice disorders.

Design: Prospective, randomized cohort study.

Methods: Fifteen patients with voice disorders phonated for 5 minutes through a VOFM with diameter openings of 3.2, 6.4, and 9.6 mm. Acoustic and aerodynamic voice measures were collected before and after each occlusion trial. These results were compared to a historical patient group that received the same phonation training for 2 minutes.

Results: Positive effect sizes were found for acoustic and aerodynamic improvements for all patients for at least one occlusion diameter. Effect sizes for aerodynamic outcomes were greater in the 5-minute conditions for both the 9.6- and 6.4-mm occlusions than the 2-minute condition. Effect sizes for acoustic outcomes were greater in the 5 minute than 2-minute trial for the 9.6- and 6.4-mm occlusion diameter, but greater in the 2 minute than 5-minute trial for 3.2-mm diameter.

Discussion: This study provides evidence that all three occlusion sizes may elicit beneficial changes for different patients; however, 5 minutes of phonation into a facemask with end occlusion of 6.4-mm diameter results in improved acoustic and aerodynamic voice outcomes for many patients with voice disorders. Future studies should further explore phonatory physiologic changes of the VOFM in a larger sample of patients and translate effects into clinical treatment for patients with voice disorders.

Keywords: Acoustic; Aerodynamic; Facemask; Semiocclusion; Therapy; Voice.