Effect of vocal fold asymmetries on glottal flow.

OBJECTIVES/HYPOTHESIS Voice disorders, such as unilateral vocal fold paralysis or paresis, and vocal fold scarring feature structural asymmetries of the vocal folds. Studies on how structural asymmetries affect voice has mostly been limited to computational simulations and experiments on mechanical models. The purpose of the current study is to examine the effects of asymmetries in left-right position, height, and length of the vocal folds on the intraglottal flow characteristics, as well as acoustics in the canine larynx model. STUDY DESIGN Basic science. METHODS Measurements of intraglottal flow velocity fields were taken in excised canine larynges using particle image velocimetry. Asymmetries of the vocal folds are induced by translating the vocal processes in space using a prong apparatus connected to a micrometer. RESULTS Asymmetries in length height and abduction produced a reduction in the intraglottal vortices strength and subsequently the glottal efficiency. CONCLUSION Current findings can affect future recommendations for surgical interventions that are used to treat unilateral vocal fold paralysis. LEVEL OF EVIDENCE NA Laryngoscope, 126:2534-2538, 2016.