Pressure-flow measurements for selected nasal sound segments produced by normal children and adolescents

The purpose of this prospective study was to: (1) report simultaneous oral-nasal pressures, nasal airflow rates, and velopharyngeal orifice areas for nasal sounds produced by children and adolescents; (2) determine whether data could be statistically classified by age, sex, or utterance type; and (3) provide guidelines for determining typical from atypical productions.

The study involved 56 subjects, with two boys and two girls representing each age from 5 to 18 years. Subjects had no history of speech therapy, were judged as having normal speech and resonance at the time of testing, and had no upper respiratory tract infections or allergies at the time of testing.

All subjects repeated /mphaaa;/ and "hamper" at normal pitch and loudness after an examiner model. Mean oral-nasal pressures, nasal airflow rates, and velopharyngeal orifice areas were calculated for each subject's utterances. A discriminate function analysis determined whether data could be grouped by age and sex.

Significant differences in mean data for age groups of 5 to 9 years, 10 to 13 years, and 14 to 18 years were observed. Data showed decreases in pressures and increases in nasal airflow and orifice areas with age. Variability in pressure stayed consistent or decreased with age, but variability in nasal airflow and orifice areas increased with age.

We propose a scheme for categorizing velopharyngeal function for oral and nasal sound production to be used in clinical testing.