Hypernasality and velopharyngeal impairment

Area of Science:

• Speech-language pathology
• Acoustic analysis
• Physiology of speech production

Background:

• Hypernasality is primarily caused by impaired velopharyngeal (VP) function.
• Listener perception of hypernasality is influenced by factors beyond VP function alone.
• Understanding these factors is crucial for accurate diagnosis and treatment.

Purpose of the Study:

• To investigate the relationship between oral-nasal resonance balance and velopharyngeal orifice area.
• To assess the correlation between hypernasality and nasal airflow rate.
• To examine the link between perceived resonance and the duration of nasal airflow.

Main Methods:

• Utilized the pressure-flow technique to estimate velopharyngeal orifice area.
• Measured nasal airflow rate and duration using the pressure-flow technique.
• Collected listener ratings of oral-nasal resonance balance on a 6-point scale.

Main Results:

• Moderate correlations were found between hypernasality ratings and VP orifice area (r=0.66), nasal airflow rate (r=0.61), and nasal airflow duration (r=0.53).
• Adults were perceived as more hypernasal than children with similar degrees of VP impairment.
• For small VP openings, the duration of opening-closing movements influenced perceived resonance.

Conclusions:

• VP orifice area, nasal airflow rate, and duration are significant contributors to perceived hypernasality.
• Age appears to be a factor in how hypernasality is perceived.
• The dynamics of velopharyngeal closure, specifically movement duration, play a role in resonance balance, particularly in cases of minimal VP opening.