Using simultaneous photodetection and nasometry to monitor velopharyngeal behavior during speech.

The purposes of this investigation were (a) to study the temporal relationships among velopharyngeal closing and opening maneuvers monitored by phototransduction and the onset and offset of Nasometer output signals and (b) to determine the extent to which photodetector output maxima are correlated with output peaks from the Nasometer when both are used simultaneously to monitor nasal productions among normal speakers. Simultaneous Nasometer and photodetector data were collected from 6 normal adult subjects as they produced 6 repetitions of 10 sentences. A major finding of this study was that over 96% of the 540 nasal utterances studied produced Nasometer and photodetector signal maxima that were within 30 ms of one another. The results of this study also suggest that simultaneous nasometry and photodetection may provide useful information concerning the temporal relationships among various velopharyngeal movements and the onset and offset of speech as indicated by output signals from the Nasometer. The potential use of this procedure with clinical patients is discussed.