The effect of tongue position on division of airflow in the presence of velopharyngeal defects.
Results of studies of nasal to oral airflow ratios are reported using simple and accurate anatomical models to record the effect of differing positions of lips, tongue and soft palate, with particular reference to the effect of the position of the dorsum of the tongue and various sizes of velopharyngeal defect. The resistances to airflow produced by the labial, palatolingual, velopharyngeal and naral valves were found to be interdependent. Variations in tongue position alone could allow the same nasal airflow during a more than three-fold variation in the size of velopharyngeal defects. The degree of nasal escape of air which is responsible for the typical "cleft palate" type of speech cannot be assessed by observation of the size of the velopharyngeal defect alone.
D002972:Cleft Palate / Q000503:physiopathology*; D006801:Humans; D008953:Models, Anatomic; D012123:Pulmonary Ventilation; D013064:Speech Disorders / Q000503:physiopathology*; D014059:Tongue / Q000503:physiopathology*