Reliability of the nasopharyngeal fiberscope (NPF) for assessing velopharyngeal function: analysis by judgment.

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.