Aerodynamic studies of cleft-palate speech.

Abstract

The aerodynamic oral-nasal factors related to the speech of two groups of cleft-palate children were evaluated. One group presented hypernasality and the other group presented normal nasal resonance. The aerodynamic parameters evaluated were oral pressure, nasal flow, and flow-pressure ratio (nasal flow/oral pressure). Oral temperature readings were also obtained. These parameters were evaluated under three conditions (1) blowing, (2) vocalizing the vowel /i/, and (3) reading eight sentences representing two different rhythm patterns, two types of consonant loadings, and two conditions of syllable stress. The findings revealed significant differences between the hypernasal and normal resonance groups in flow-pressure ratio, oral pressure, and nasal flow while subjects were reading sentences. However, only a small proportion of the variability in these aerodynamic measurements could be accounted for based on the classification of hypernasality or normal nasal resonance. Oral-nasal aerodynamic studies done during speaking activity are more useful clinically than blowing activity or saying vowel sounds. No aerodynamic differences were noted between the two groups for the different rhythm and stress patterns and phonemic loadings within the sentences used.