Modelling sound production from an aerodynamical model of the human newborn larynx

Considering on the one hand the important histological differences that exist between newborn and adult vocal folds and on the other hand the specifical subglottal pressure at birth, the sound production in a newborn larynx is studied. The laryngotracheal airflow has been numerically modelled in order to evaluate its role in voice production by the larynx in newborn. The FFT spectrum of the pressure signal acquired just above the vocal folds was calculated and compared to the spectrum of a sound generated by an excised larynx. It can be determined that first, the computed pressure signal has a fundamental frequency close to that obtained experimentally with an excised larynx, and second the FFT spectra are qualitatively similar to one another. Third, the computed pressure fluctuation is strong enough to be detected by the human ear. The conclusion is that the airflow and the aerodynamical phenomena observed in a rigid geometry are, by themselves, able to produce a sound and consequently, are one of the several elements leading to sound production in the newborn larynx.