Vocal fold bulging effects on phonation using a biophysical computer model

Glottal adduction is a primary laryngeal variable that helps to determine g lottal configuration and phonatory output. Greater adduction of the vocal f olds can be produced by narrowing the gap between the vocal processes or by bulging the medial surface of the vocal folds. This study examined phonato ry effects due to changing the degree of bulging using a computational mode l. Bulging was modeled as a quadratic surface and was related to active mus cle stress. Results indicated that bulging had a significant effect on glot tal now resistance, maximum glottal width and area, and mean glottal volume velocity. The results are discussed relative to clinical issues of hyperfu nction.