Warren D W, Dalston R M, Dalston E T
Department of Dental Ecology, University of North Carolina, Chapel Hill 27599.
Cleft Palate J. 1990 Jan;27(1):53-8; discussion 58-60. doi: 10.1597/1545-1569(1990)027<0053:mspitp>2.3.co;2.
Most, but not all, individuals with velopharyngeal inadequacy maintain consonant pressures greater than 3 cm H2O even with decreased velar resistance. The purpose of this study was to identify variables that might differentiate those who achieve adequate pressures from those who do not. Forty-four cleft lip and/or palate subjects were assessed during production of /p/ in the word "hamper." Twenty-three subjects achieved pressures greater than 3 cm H2O and 21 did not. The pressure-flow technique was used to assess velopharyngeal orifice size, nasal resistance, velar resistance, and nasal airflow during speech. Nasal cross-sectional area was measured during breathing. The data were analyzed by age and gender. Results indicate that the inability to achieve adequate consonant pressures in the presence of velopharyngeal inadequacy is more likely to occur in adults than in children. Although children are known to produce consonants at higher pressures than adults, the age disparity between groups did not account for the pressure differences. The most significant factor differentiating adequate and low pressure speakers was the magnitude of nasal plus velar resistance. This difference was consistent across age and gender.
