Reliability of the Nasopharyngeal Fiberscope (NPF) for Assessing Velopharyngeal Function: Analysis by Judgment

Abstract

The reliability and validity of data about velopharyngeal function obtained with the nasopharyngeal fiberscope was assessed in normal subjects. The experimental design included data reduction procedures that are likely to have clinical utility (clinical ratings). The results indicated that relative velar movement and size of the velopharyngeal port may be reliably and validly estimated using the procedures. However NPF estimates of lateral pharyngeal wall movement were not reliable. Finally, the data indicated that velar movement and size of V—P port were consistent within subjects and tasks across data collection sessions. Data about consistency of lateral wall movement across sessions was inconclusive, however. Additional research involving similar procedures with subjects who have morphologic deficits is indicated. A previous report (Ibuki, Karnell, and Morris, 1983) described the nasopharyn-geal fiberscope (NPF), its stability of placement for assessing velopharyngeal function , and some information about reliability and validity of NPF findings when they are analyzed by measurement. Those studies indicated that, with the criterion of acceptability of the NPF view that all bound— aries of the velopharyngeal mechanism are visible in a single NPF View, the fiberscope can be placed on repeated occasions in a reliable fashion. The data also indicated that the reliability of a trace-and-measure method of analysis is satifactorily high, except for determination of left lateral pha-ryngeal wall movement. This exception may be an artifact of our practice ofinsert— ing the fiberscope in the right nostril (into the right nasal passageway).