Accuracy of the Pressure-Flow Method in Estimating Induced Velopharyngeal Orifice Area Effects of the Flow Coefficient Research Note
Research Note  |   October 01, 1991
Accuracy of the Pressure-Flow Method in Estimating Induced Velopharyngeal Orifice Area
 
Author Affiliations & Notes
  • David J. Zajac
    Cleft Palate-Craniofacial Center School of Dental Medicine University of Pittsburgh
  • Campbell C. Yates
    Cleft Palate-Craniofacial Center School of Dental Medicine University of Pittsburgh
  • Requests for reprints should be sent to David J. Zajac, PhD, 313 Salk Hall, University of Pittsburgh, Pittsburgh, PA 15261
Article Information
Speech, Voice & Prosodic Disorders / Special Populations / Speech, Voice & Prosody / Speech / Research Notes
Research Note   |   October 01, 1991
Accuracy of the Pressure-Flow Method in Estimating Induced Velopharyngeal Orifice Area
Journal of Speech, Language, and Hearing Research, October 1991, Vol. 34, 1073-1078. doi:10.1044/jshr.3405.1073
History: Received August 2, 1990 , Accepted January 11, 1991
 
Journal of Speech, Language, and Hearing Research, October 1991, Vol. 34, 1073-1078. doi:10.1044/jshr.3405.1073
History: Received August 2, 1990; Accepted January 11, 1991

A two-part study was conducted to determine the accuracy of the pressure-flow method in estimating induced velopharyngeal orifice areas when the flow coefficient k was empirically determined. In Study 1, short tubes, 4.5 cm in length and with internal diameters of 3.2, 4.8, and 6.4 mm, were placed in a model of the vocal tract, and the associated flow coefficients were calculated. In Study 2, the 4.8-mm internal diameter tube was inserted into the nasopharynx of a normal adult subject to induce oronasal coupling during production of the syllable I/pa/. Results for the human subject revealed that the error between the known and estimated orifice areas was approximately 7%. This finding indicates that the pressure-flow technique is accurate when the flow coefficient of the orifice is known. It is suggested that future research attempt to estimate flow coefficients associated with the geometry of the human velopharyngeal orifice in order to improve the accuracy of the pressure-flow technique.

Acknowledgments
This study was supported in part by a grant from the National Institute of Dental Research (DE01697-29). We would like to thank Betty Jane McWilliams for her helpful comments on the manuscript and James Kuo for his assistance with the collection of the model data.
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