Use of nasometry as a diagnostic tool for identifying patients with velopharyngeal impairment.

A series of 117 patients were studied in an attempt to determine the extent to which acoustic assessments of speech made with a Kay Elemetrics Nasometer corresponded with aerodynamic estimates of velopharyngeal area and clinical judgments of hypernasality. Nasometer data were obtained while patients read or repeated a standardized passage with no nasal consonants. Pressure-flow data were obtained from 96 of these patients during repeated productions of the word "papa." Listener judgments were made in a clinical setting by the senior author using a 6-point equal-appearing interval scale. Nasometer and pressure-flow results were not known to the senior author when making listener assessments. With a cutoff nasalance score of 32, the sensitivity of Nasometer ratings in correctly identifying the presence or absence of velopharyngeal areas in excess of 0.10 cm2 was 0.78 and 0.79, respectively. The sensitivity and specificity of nasometry in correctly identifying subjects with more than mild hypernasality in their speech was 0.89 while the specificity was 0.95. The results suggest that the Nasometer is an appropriate instrument that can be of value in assessing patients suspected of having velopharyngeal impairment.