DeJonckere Philippe Henri, Lebacq Jean, Titze Ingo R
Neurosciences, University of Leuven and Federal Agency for Occupational Risks, Brussels, Belgium.
Neurosciences Institute, University of Louvain, Brussels, Belgium.
J Voice. 2017 Nov;31(6):649-661. doi: 10.1016/j.jvoice.2017.03.001. Epub 2017 May 8.
Intraglottal pressure is the driving force of vocal fold vibration. Theoretically, simultaneous quantification of glottal area and transglottal airflow allows the calculation of the intraglottal pressure waveform during a single vibration cycle. In this study, we show that, by combining photoglottography (transglottal light transmission) and airflow (Rothenberg mask) measurements during sustained vocal emissions in vivo, the intraglottal pressure wave can be approximated in a way similar to what has been done in models. The results confirm in vivo that the intraglottal pressure is systematically larger during the opening phase than during the closing phase, so that over one whole cycle, the driving force performs net positive work, accounting for sustained vocal fold motion. A component of this driving force asymmetry is related to vocal tract inertance, which also accounts for the skewing of the airflow waveform compared with the area waveform. Furthermore, the intraglottal pressure ratio (opening:closing) increases with voicing intensity, reaches a maximum around 76 dB, and significantly decreases at higher intensities. This rise and fall suggests that there is a range of intensity values in which, mechanically, a maximum of the driving force is imparted to the vocal fold mass. This finding could have implications for voice economy in professional speakers.
声门内压是声带振动的驱动力。理论上，同时对声门面积和跨声门气流进行量化，能够计算出单个振动周期内的声门内压波形。在本研究中，我们表明，通过在体内持续发声时结合光声门图（跨声门光传输）和气流（罗滕伯格面罩）测量，声门内压波能够以类似于模型中的方式进行近似估算。结果在体内证实，声门内压在开放期系统性地大于关闭期，因此在整个周期内，驱动力做净正功，这解释了声带的持续运动。这种驱动力不对称的一个因素与声道惯性有关，这也解释了气流波形相对于面积波形出现偏斜的原因。此外，声门内压比（开放：关闭）随发声强度增加，在约76分贝时达到最大值，并在更高强度时显著降低。这种上升和下降表明，在一定强度值范围内，从机械角度而言，驱动力会最大程度地作用于声带质量。这一发现可能对职业演讲者的发声经济性具有启示意义。
