Registers in Infant Phonation.
Eugene H Buder, Valerie F McDaniel, Edina R Bene and 2 others
PMID 29650330WHAT IT FOUND
Three typical infants spontaneously shifted within one vocalization from modal voice to loft-like high-pitched or pulse-like rasping voice.
For SLPs, pitch alone may not identify these qualities.
Key findings
01Three typically developing female infants produced within-vocalization transitions between modal and loft-like or pulse-like phonation at each sampled age.
02Loft-like phonation had a stronger first harmonic than second harmonic, while modal and pulse phonation had a stronger second harmonic than first.
03Pulse-like phonation was fully predicted by pitch alone, with a modal-versus-pulse threshold of 208.5 Hz.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
Only three female infants were studied, all typically developing, so the findings may not apply to boys, older infants, or infants with voice or developmental disorders. The infants were sampled at only three age bands, and the authors did not find age effects in this limited dataset. Coders were not trained to reliably distinguish true loft from modal, and the high-modal code included high-pitched segments that may not have been loft. Many measures depended on manually determined pitch in noisy infant recordings, and ambiguous cases were excluded. The study reports no clinical outcomes, no intervention, and no comparison with disordered populations.
The easy way to misread this
Do not conclude that high-pitched rasping infant vocalizations are clinically abnormal. In this small sample, pulse-like phonation was identified at a modal-versus-pulse threshold of 208.5 Hz, and no clinical outcomes were measured.