Biomechanics Laboratory, Department of Mechanical Engineering, McGill University, Montreal, QC, Canada.
J Voice. 2012 Nov;26(6):688-97. doi: 10.1016/j.jvoice.2011.09.003. Epub 2012 Apr 7.
Dehydration may alter vocal fold viscoelastic properties, thereby hampering phonation. The effects of water loss induced by an osmotic pressure potential on vocal fold tissue viscoelastic properties were investigated. Porcine vocal folds were dehydrated by immersion in a hypertonic solution, and quasi-static and low-frequency dynamic traction tests were performed for elongations of up to 50%. Digital image correlation was used to determine local strains from surface deformations. The elastic modulus and the loss factor were then determined for normal and dehydrated tissues. An eight-chain hyperelastic model was used to describe the observed nonlinear stress-stretch behavior. Contrary to the expectations, the mass history indicated that the tissue absorbed water during cyclic extension when submerged in a hypertonic solution. During loading history, the elastic modulus was increased for dehydrated tissues as a function of strain. The response of dehydrated tissues was much less affected when the load was released. This observation suggests that hydration should be considered in micromechanical models of the vocal folds. The internal hysteresis, which is often linked to phonation effort, increased significantly with water loss. The effects of dehydration on the viscoelastic properties of vocal fold tissue were quantified in a systematic way. A better understanding of the role of hydration on the mechanical properties of vocal fold tissue may help to establish objective dehydration and phonotrauma criteria.
脱水可能会改变声带的黏弹性特性，从而影响发声。本研究旨在探讨渗透压引起的水分流失对声带组织黏弹性特性的影响。通过将猪声带浸泡在高渗溶液中进行脱水，对其进行长达 50%的准静态和低频动态牵引测试。利用数字图像相关技术，从表面变形确定局部应变。然后确定正常和脱水组织的弹性模量和损耗因子。采用八链超弹性模型来描述观察到的非线性应力-应变行为。与预期相反的是，组织质量随时间的变化表明，当组织浸泡在高渗溶液中时，会在循环拉伸过程中吸收水分。在加载历史中，随着应变的增加，脱水组织的弹性模量增加。当负载释放时，脱水组织的响应受影响较小。这一观察结果表明，在声带的细观力学模型中应考虑到水合作用。与发声努力相关的内滞后通常会显著增加，而脱水会导致内滞后显著增加。本研究系统地量化了脱水对声带组织黏弹性特性的影响。更好地了解水合作用对声带组织力学特性的影响，可能有助于建立客观的脱水和声创伤标准。
