Oral vibratory sensations during voice production at different laryngeal and semi-occluded vocal tract configurations

Abstract

Voice therapy often emphasizes vibratory sensations in the front part of the vocal tract during phonation to improve vocal efficiency. It remains unclear what laryngeal and vocal tract adjustments are elicited in speakers by this emphasis on oral vibratory sensations. Using a three-dimensional phonation model, this study aims to identify laryngeal and epilaryngeal adjustments that might produce maximal oral vibratory sensations during phonation, as quantified by the oral sound pressure level (SPL), and thus are likely to be elicited in voice therapy at different semi-occluded vocal tract configurations. Results show that maximum oral SPL occurs at intermediate vocal fold adduction configurations characterized by a trade-off between glottal gap and vocal fold vertical thickness. Epilaryngeal tube narrowing further increases the oral SPL in an open vocal tract, but has little effect on oral SPL in semi-occluded vocal tracts. Laryngeal and epilaryngeal configurations producing the maximum oral SPL generally have lower peak vocal fold contact pressure when producing a target output SPL. These favorable configurations are more easily identified in open vocal tracts than semi-occluded vocal tracts. However, semi-occlusion increases both the mean and dynamic oral pressure, which may familiarize speakers with oral vibratory sensations and facilitate adoption of favorable laryngeal configurations.

Schlieren imaging and video classification of alphabet pronunciations: exploiting phonetic flows for speech recognition and speech therapy

“…Speech production involves a complex feedback mechanism that includes hearing, perception, and information processing within the brain. Similarly, speech therapy often utilizes auditory feedback and lip reading to evaluate and treat speech and language disorders [ 5 , 6 ]. In contrast to these conventional techniques, this study suggests that a schlieren-based speech flow visualization system can link the three most relevant observables: sound, oral motor, and speech flow.…”

“…The brain requires multiple forms of feedback to iteratively correct the oral motors for accurate pronunciation. Other techniques are often implemented to help patients generate more meaningful feedback, such as placing a fingertip on the lips or cheek to feel motion or exhaling onto a piece of paper to feel the flow [ 5 ]. While these methods are easy to implement and have proven useful in helping patients correct their articulations, they are limited by indirect feedback and interference with normal speech.…”