[A phonation-related phase-model of the velopharyngeal closure based on high resolution manometry]

The production of many speech sounds requires a complete velopharyngeal closure (VPC) caused by muscular contractions and approximation of the pharyngeal walls. The contraction pressure of the muscles involved needs to be high enough to withstand phonation pressure. It is postulated that sustained phonation consists of 3 velopharyngeal phases: an initial pressure buildup, a steady state and a final pressure decrease. To test this hypothesis, phonation induced pressure changes in the VPC were measured in healthy participants.

High resolution manometry was performed on 8 participants during the sustained phonation of the vowel / i:/. Individual pressure curves have been compared in order to verify the postulated model and intraindividual reproducibility has been tested.

The intraindividual pressure curves were found to be reproducible, but an interindividual variation was observed. An initial pressure increase was detected in all participants at the onset of phonation, followed by a stable phase during sustained phonation. At the offset the pressures returned to the initial value during rest.

The postulated model was verified in all participants. An initial phase, a stable phase and a terminal phase could be differentiated. Further classifications can be made regarding the on- and offset of phonation allowing for a more detailed characterization of the VPC. Further studies should evaluate if this model is useful to describe changes in the VPC pressure profile of patients affected by rhinophonia.