Abstract:

This case study investigates the difference between children’s fundamental frequency (F0) during structured and unstructured activities, building on the concept that task type influences F0 values. A healthy male child (67 months) was evaluate d (31 h, 4 days). During all activities, a National Center for Voice and Speech voice dosimeter was worn to measure long-term unstructured vocal usage. Four structured tasks from previous F0 studies were also completed: (1) sustaining the vowel ∕ɑ∕, (2) sustaining the vowel ∕ɑ∕ embedded in a phrase-end word, (3) repeating a sentence, and (4) counting from one to ten. Mean F0 during vocal tasks (≈257 Hz), as measured by the dosimeter and acoustic analysis of microphone data, matched the literature’s average results for the child’s age. However, the child’s mean F0 during unstructured activities was significantly higher (376 Hz). The mode and median of the vocal tasks were respectively 260 and 259 Hz, while the dosimeter’s mode and median were 290 and 355 Hz. Results suggest that children produce significantly different voice patterns during clinical observations than in routine activities. Further, long-term F0 distribution is not normal, making statistical mean an invalid measure for such. F0 mode and median are suggested as two replacement parameters to convey basic information about F0 usage.