Air pulse stimulations for measuring vocal fold viscoelasticity

Hans Larsson and Stellan Hertegård

Tissue viscoelasticity is a critical factor for vocal fold vibration. Aberration in the elasticity of the vocal folds is a common course for vocal fold dysfunction. At present there is no clinically usable method for vocal fold elasticity measurement.
Air is the medium which drives vocal fold vibration, so our idea is to use air to blow on the vocal folds and to measure the resulting mucosal response. Thepulses are administrated via a tubing and feed to the vocal folds via the working channel on a flexible endoscope. As the equipment is not in contact with the vocal folds it is possible to measure with no or only slight local anesthesia. The effect of the air pulse stimulation is automatically measured with a laser fiber system controlled by a PC. From of the measurement data is it possibleto calculated the local viscoelasticity, Young’s modulus equivalent. Data from preliminary tests show that is possible to get realistic values but it is difficult to direct the probe to desired position and to obtain oblique angle.

Hans Larsson
Dept of Logopedics and Phoniatrics
B69 Karolinska Institutet/Huddinge
141 86 Stockholm Sweden
Phone +468 585 87405 Fax +468 585 81505 
hans.larsson@ki.se