Regulation of intraoral air pressure during speech

Abstract

Speakers with velopharyngeal dysfunction produce higher intraoral air pressure than that obtained by simulating velopharyngeal openings using a passive mechanical model of the vocal tract and a compressed air source. It has been inferred that, in order to maintain air pressures within a regulated range, speakers with velopharyngeal dysfunction compensate for the leakage of air through the velopharyngeal port by altering their respiratory or vocal tract movements. An alternative explanation may be that, instead of depending on an active compensation, the pressure is maintained by the characteristics of the respiratory system. Previous modeling experiments have used an air source with constant flow into the vocal tract. However, it may be that the respiratory system acts more like a constant pressure source than a constant flow source, in which case the intraoral pressures would not be changed by the presence of a velopharyngeal leak. Experiments are reported comparing mechanical models of speech aerodynamics with constant flow and constant pressure inputs. Also reported on are experiments comparing vocal tract aerodynamics measured during speech with data from constant‐flow and constant‐pressure models.