[Study of the supra-glottic pressure during partial constriction of the vocal tract]

Phonation in a small plastic tube 22 cm length and 5 mms diameter (basic exercise of the method of Dr Amy de la Brèteque), is current practice in vocal rehabilitation in France. This work aims to show the effects of this method on the glottic vibration. The hypothesis was that at the time of phonation in the tube with a strong flow as recommended in the method, the vocal cords vibrate without contact. This limits the mechanical trauma at this level.

We have analyzed the sound production in a tube in 11 trained and not trained subjects. We simultaneously collected the intra-oral air pressure and the vocal signal which was subjected to a spectral analysis.

Spectral analysis confirmed that the signal was produced correctly i.e. with a strong flow and without interruption of the sound less rich in harmonics. We interpreted these results in the light of our preceding works on the glottic vibration and we show that this vocal production was of the sinusoidal type; this implies the absence of physical contact between the vocal cords, which validates our hypothesis.

Further works are necessary to better understand the physical relations between the supra-glottic aerodynamic phenomena and the vibratory functioning of the vocal cords and also to analyze the therapeutic potential ofthe method within speech therapy rehabilitation.