Aerodynamic measurements: normative data for children ages 6:0 to 10:11 years.

Normative measures of open quotient, speed quotient, maximum flow declination rate (MFDR), and subglottal pressure were determined for 75 children between the ages of 6 years 0 months and 10 years 11 months. The participants produced a sustained /a/ at low, comfort, and high pitches for a minimum of 5 seconds, and five to seven repetitions of /pa/ at low, comfort, and high pitches. No statistically significant differences were found in the mean measures of any aerodynamic variables (open quotient, speed quotient, maximum flow declination rate, subglottal pressure) between the frequency levels (low, comfort, high pitches). Also, no strong evidence (P > .05) exists that age or sex effect differed between the frequency levels (low, comfort, high) for any of the aerodynamic measures. For /a/ response tasks, mean open quotient measures increased slightly from low to comfort frequency and from comfort to high frequency. Mean speed quotient measures showed minimal differences between low and comfort frequency, with decreased mean measures for high frequency. Mean MFDR measures increased from low to comfort frequency and from comfort to high frequency. Mean subglottal pressure measures increased slightly from low to comfort frequency and from comfort to high frequency.