ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

5aSP4. Stress-strain response of the human vocal ligament and its effect on F[sub 0] control.

Ingo R. Titze

Young B. Min

Fariborz Alipour-Haghighi

Natl. Ctr. for Voice and Speech and Dept. of Speech Pathol. and Audiol., Univ. of Iowa, Iowa City, IA 52242

The longitudinal elastic properties of the human vocal ligament were quantified by stress-strain measurements and by modeling the response mathematically. Human ligaments were obtained from surgery and autopsy cases. They were dissected, mounted, and stretched with a dual-servo ergometer to measure force versus elongation and to convert the results into stress and strain. To calculate a longitudinal Young's modulus, the stress-strain curves were fitted with polynomial and exponential functions and differentiated. Young's modulus was separately defined in the low and high strain regions. The mean Young's modulus for the low strain region was 33.1(plus or minus)10.4 kPa. In the high strain region, A and B parameters for an exponential fit in the high strain portion were 1.4(plus or minus)1.0 and 9.6(plus or minus)1.2 kPa, respectively. The stress-strain and Young's modulus curves showed the typical hysteresis and nonlinearity seen previously in other vocal fold tissues (muscle and mucosa), but the nonlinearity was most profound for the vocal ligament. The effect of these results on F[sub 0] control will be discussed. [Work supported by NIDCD Grant No. DC00976.]