Quantitative Endoscopic Phototransducer Investigation of Normal Velopharyngeal Physiology

Purpose: The purpose of this research was to learn the extent to which healthy individuals vary in their ability to achieve velopharyngeal closure for speech. Method: Twenty healthy adult volunteers (10 women, 10 men) were tested using an endoscopic phototransducer system that tracks variations in velopharyngeal closure during speech production. Each speaker produced multiple repetitions of three utterances that differed in phonetic content. The data were amplitude normalized and averaged for each speaker. Results: Average phototransducer measurements were similar across subjects for utterances containing only oral phonemes. Average percentage of velopharyngeal closure varied considerably among subjects when producing utterances containing both oral and nasal phonemes (54%-95%). Average percentage of velopharyngeal closure levels were significantly lower (p < 0.05) for utterances that included nasal consonants. Conclusions: Phototransducer measurements of velopharyngeal closure for speech are sensitive to nasal phoneme content. The findings suggest that motor programming that accomplishes rapid oral-nasal velopharyngeal valving for speech may differ among healthy subjects. However, such variations in motor programming may not perceptually affect typical speakers. If present in individuals with abnormal velopharyngeal mechanisms, these variations may help explain variations among speakers in speech outcomes after physical and behavioral management.