Experimental study for quantification of traveling mucosal wave of the vocal fold

声带振动本质上是从声带下表面产生的粘膜行波的传播。黏膜行波速度(TWV)可定量评价黏膜波。在第一年，我们研究了发声时TWV和垂直声带运动速度(VVT)的关系。用激光测振仪(LDV)测量VVT，同时测量行波在声带上两个标记物之间以已知距离移动的时间，同时测量TWV。TWV与VVT呈显著正相关(相关系数为0.90~0.98)，提示VVT与TWV均可作为反映胃粘膜行波的有用指标。在第二年，我们同时记录了三种情况下声带的垂直和水平运动。LDV测量垂直运动，光声门图(PGG)测量水平运动。这两个动作结合在一起，画出了发声过程中声带的李萨如轨迹。两个方向的振幅随着气流的增加而增大。在犬喉中，甲状软骨收缩在开放初期引起垂直增大，在开放后期引起水平增大。另一方面，在人类的喉部，垂直方向的增大更为明显，而水平方向的幅度则变得更小。这种差异可能与人类喉部较薄的固有层和较厚的声门肌有关。

Vocal fold vibration is essentially propagation of mucosal traveling wave arising from the lower surface of the vocal fold. Velocity of the mucosal traveling wave (TWV) could quatitatively assess the mucosal wave. In the first year, We examined relationship between TWV and velocity of vertical vocal fold movement (Vvt) during phonation. Vvt was measured with the aid of laser doopler vibrometer (LDV) while TWV was simultaneously obtained by measuring the duration of time the traveling wave moved between two markers placed on the vocal fold with a known distance. TWV and Vvt had a significantly high correlation (correlation coefficient : 0.90 to 0.98), which suggested that Vvt as well as TWV is an useful index of mucosal traveling wave. In the second year, we recorded vertical and horizontal movements of thc vocal fold simultaneously under three conditions. Vertical movement was obtained using LDV and horizontal movement was measured with the aid of photoglottography (PGG). The two movements were combined to draw Lissajous trajectories of the vocal fold during phonation. Amplitude in the two direction increased when airflow was increased. In the canine larynx, thyroarytenoid contraction caused vertical enlargement during initial stage of thc opening phase and caused horizontal enlargement during late stage of the opening phase. On the other hand, in the human larynx, vertical enlargement was prominent while horizontal amplitude became even smaller. The difference may be ascribed to relatively thin lamina propria and thick vocalis muscle in thc human larynx.