Effects of a Variably Occluded Face Mask on the Aerodynamic and Acoustic Characteristics of Connected Speech in Patients With and Without Voice Disorders

Abstract

This study reports on experiments designed to examine the effects of a variably occluded face mask (VOFM) on (a) estimated subglottal pressure (Psub) in normophonic participants and (b) aerodynamic and acoustic characteristics of voice in dysphonic participants. A prospective design was used for experiment 1, and a prospective, randomized cohort design was used for experiment 2. The outlet ports of disposable anesthesia face masks were fitted with plastic caps with variable diameter drilled openings (9.6, 6.4, 3.2, and 1.6 mm) to create a series of mask openings. In experiment 1, Psub was measured in normophonic participants using the face mask during syllable repetitions in unoccluded and variable diameter opening conditions. In experiment 2, aerodynamic and acoustic measures were obtained in a group of dysphonic speakers before and after syllable and speech repetition tasks using the VOFM. In experiment 1, mean PSub was observed to decrease while using the VOFM in all occlusion conditions versus nonocclusion, with a significant reduction in Psub observed between the baseline and the 6.4 mm condition. In experiment 2, standardized mean differences showed that many dysphonic participants produced reduced Psub, increased airflow, and improved acoustic measures after the use of the VOFM in at least one occlusion condition. Beneficial changes in both aerodynamic and acoustic characteristics of voice may be obtained in dysphonic speakers using a VOFM. By moving the place of occlusion outside of the oral cavity, therapeutic stimuli options may be extended beyond vowel and humming elicitations to syllable and speech contexts and assist with generalization of voice therapy targets to conversational speech.