Intraoral pressure and velopharyngeal function

The objective of this study was to determine the influence of velopharyngeal (VP) inadequacy on respiratory speech compensations.

The pressure-flow technique was used to measure pressure, airflow, and timing variables associated with VP closure during the production of the initial plosive consonant /p/ in a series of the utterance "papa."

The study was conducted in the speech and breathing laboratory of the UNC Craniofacial Center.

Eighty-two subjects with cleft lip and/or palate were assessed. The subjects were divided into two groups, those with adequate VP closure (VP size <.010 cm2) and those with inadequate VP closure (VP size >0.10 cm2). The adequate group was comprised of 62 subjects, and 20 subjects were categorized as inadequate.

Peak intraoral pressure decreased in the inadequate group, but the difference was not significant. Nasal airflow increased (p < .01), but duration of the pressure pulse was the same for both groups. The area under the pressure curve decreased for the inadequate group (p = .04).

These data contrast with previously reported published data using /p/ in the utterance "hamper." This suggests that phonetic context influences the compensatory response to velopharyngeal inadequacy. Additionally, while the findings are somewhat similar to studies that involved noncleft subjects whose oral airway was suddenly vented during the production of /p/, there is enough difference to suggest that learning also affects the compensatory outcome.