Influencing Oral-nasal Balance in Speech and Song

Oral-nasal balance is dependent on the valving of the velopharyngeal sphincter. This dissertation examined the control and modification of oral-nasal balance in speech and song. Literature was reviewed from the fields of speech science and singing voice pedagogy, which motivated three projects. The first project (Santoni et al., 2018) explored the role of altered nasal signal level feedback on the regulation of oral-nasal balance in singing in trained and untrained singers. Results indicated that all participants showed lower nasalance scores in response to both increased and decreased nasal signal level feedback. The findings implied that trained singers’ internal models for controlling oral-nasal balance may not be as refined as those that guide other vocal parameters. The second project (Santoni et al., 2019) explored the influence of voice focus adjustments (forward and backward vocal tract shape and length modifications) (Boone, 2007; Boone et al., 2010) on the control of oral-nasal balance in typical speakers in speech and song. Results indicated that forward focus led to higher and backward focus to lower nasalance scores. There was one exception wherein one female participant produced lower nasalance scores in forward focus during the nasal stimulus. The results confirmed that voice focus maneuvers influence oral-nasal balance in typical speakers. Findings from project 2 led to the clinical experiment described in project 3. The third project (Santoni, Thaut Bressmann, 2020) explored the influence of voice focus adjustments on the control of oral-nasal balance in speakers with hypernasality in speech and song. Results indicated that for a group of five speakers with hypernasality, forward focus resulted in higher and backward focus resulted in lower nasalance scores. There was one exception wherein one male participant produced lower nasalance scores in forward focus during the nasal stimulus. The results provided preliminary evidence that voice focus maneuvers influence oral-nasal balance in speakers with hypernasality. With further development of the voice focus method, the intervention could become a useful therapeutic approach for speakers with hypernasality.Ph.D