Biomaterial Database

Accuracy of the pressure-flow method in estimating induced velopharyngeal orifice area: effects of the flow coefficient. 1991

D J Zajac, and C C Yates

Cleft Palate-Craniofacial Center, School of Dental Medicine, University of Pittsburgh.

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/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.

UI	MeSH Term	Description	Entries
D008722	Methods	A series of steps taken in order to conduct research.	Techniques,Methodological Studies,Methodological Study,Procedures,Studies, Methodological,Study, Methodological,Method,Procedure,Technique
D008961	Models, Structural	A representation, generally small in scale, to show the structure, construction, or appearance of something. (From Random House Unabridged Dictionary, 2d ed)	Model, Structural,Structural Model,Structural Models
D010160	Palate, Soft	A movable fold suspended from the posterior border of the hard palate. The uvula hangs from the middle of the lower border.	Velum Palatinum,Soft Palate,Palates, Soft,Palatinum, Velum
D010614	Pharynx	A funnel-shaped fibromuscular tube that conducts food to the ESOPHAGUS, and air to the LARYNX and LUNGS. It is located posterior to the NASAL CAVITY; ORAL CAVITY; and LARYNX, and extends from the SKULL BASE to the inferior border of the CRICOID CARTILAGE anteriorly and to the inferior border of the C6 vertebra posteriorly. It is divided into the NASOPHARYNX; OROPHARYNX; and HYPOPHARYNX (laryngopharynx).	Throat,Pharynxs,Throats
D011312	Pressure	A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Pressures
D012123	Pulmonary Ventilation	The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.	Respiratory Airflow,Ventilation Tests,Ventilation, Pulmonary,Expiratory Airflow,Airflow, Expiratory,Airflow, Respiratory,Test, Ventilation,Tests, Ventilation,Ventilation Test
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013060	Speech	Communication through a system of conventional vocal symbols.	Public Speaking,Speaking, Public
D014681	Velopharyngeal Insufficiency	Failure of the SOFT PALATE to reach the posterior pharyngeal wall to close the opening between the oral and nasal cavities. Incomplete velopharyngeal closure is primarily related to surgeries (ADENOIDECTOMY; CLEFT PALATE) or an incompetent PALATOPHARYNGEAL SPHINCTER. It is characterized by hypernasal speech.	Palatopharyngeal Incompetence,Inadequate Velopharyngeal Closure,Velopharyngeal Incompetence,Incompetence, Palatopharyngeal,Incompetence, Velopharyngeal,Insufficiency, Velopharyngeal,Velopharyngeal Closures, Inadequate