Exploration of the Influences of Temporary Velum Paralysis on Auditory-Perceptual, Acoustic, and Tomographical Markers.

Abstract

Purpose To better understand hypernasality (HN), we explored the relations between velopharyngeal orifice, auditory perception of HN, and acoustic-spectral measures in an in vivo within-subject design: (a) with a normally functioning velum as the control condition and (b) with a temporarily paralyzed velum as the experimental condition. Method The velum of eight volunteers was injected with ropivacaine hydrochloride (Naropin) in the area of the levator veli palatini and tensor veli palatini muscles to induce temporary velopharyngeal inadequacy (VPI) and HN. Sustained [a] and [i] and oronasal text readings were recorded, and 3D cone-beam computed tomography images of the vocal tract were built before and during velar anesthesia. Differences between conditions and correlations in normal-to-numb differences between velopharyngeal cross-sectional area (VParea), mean ratings of HN severity, and nine acoustic-spectral measures were determined. Results Three subjects already had some incomplete velopharyngeal closure in the control condition. Temporary motor nerve blockage of the velum (increased VParea) was accomplished in seven subjects, leading to increased HN and changes in three acoustic-spectral measures. Furthermore, significant correlations only emerged between VParea, HN, and ModelKataoka. Conclusions In most of the participants, it was possible to temporarily increase the velopharyngeal orifice to investigate HN while controlling other speech variables and cephalic morphology. Although this study was exploratory and its are findings preliminary, it provided additional evidence for the possible clinical value of ModelKataoka, A 3-P 0, and B F1 for the objective measurement of VPI or HN.