Maximum phonation time for children with normal voices.

Maximum phonation time (MPT) data were collected for 286 male and female children between the ages 3-6 and 17-11. Subjects sustained phonation of the vowel/a/for 14 consecutive trials. The influence of sex, age, and multiple trials on MPT was studied. The group mean MPT for the male subjects was significantly longer than for the female subjects. Generally, phonation time increased with age for both sexes. A definite monotonic increase in length of sustained phonation was not apparent across all age levels. Optimum MPT performance can be enhanced by using repeated trials, and by providing visual feedback and encouragement regarding depth of inhalation, verbal instructions and encouragement regarding increased phonation time, and visual feedback regarding length of sustained phonation prior to and during each trial. The large intra- and intersubject variability in MPT performance reported in this study prevents valid individual-group mean MPT comparisons. A more discriminatory clinical interpretation of MPT is necessary.