Assessment of Velopharyngeal Function : Comparison of Various Methods.

Abstract

Precise estimation of velopharyngeal function is the essential first step in treating cleft palate speech either by surgery or by speech therapy. The methods in use at our daily clinic include judgement of speech, oral-inspection, rhinometric mirror, pneumotachography, velopharyngeal radiography, videonasoendofiberscopy, videofluororadiography and computerized tomography. Evaluation of velopharyngeal function on the basis of auditory impression, especially of nasality, is clinically important but requires accumulated experiences. This paper emphasizes the usefulness of 3 methods in particular : videonasoendofiberscopy, videofluororadiography and computerized tomography. Videonasoendofiberscopy provides direct visual information on the velopharyngeal closure during speech activity but quantitative analysis is impossible. There is also a problem in reproducibility and reliability due to possible different position of the fiberscope on each test. Videofluororadiography permits dynamic and quantitative assessment of velopharyngeal closure when the video-images are repeatedly displayed for measurement. Two directional projections--lateral and antero-posterior--are recommended for full understanding of the velopharyngeal function. It is also advantageous in that the relation between velopharyngeal function and articulatory lingual movement can be well visualized. A most modern computerized tomography can demonstrate the velopharyngeal aperature on a calibrated scale.