The objective occlusion effect induced by bone-conducted stimulation refers to the low frequency acoustic pressure increase that results from occluding the ear canal opening. This phenomenon is commonly interpreted as follows: the bone-conducted sound “leaks” through the earcanal opening and is “trapped” by the occlusion device. This instinctive interpretation misrepresents the fundamental mechanism of the occlusion effect related to the earcanal impedance increase and already highlighted by existing electro-acoustic models. However, these models simplify the earcanal wall vibration (i.e., the origin of the phenomenon) to a volume velocity source which, in the authors' opinion, (i) hinders an exhaustive comprehension of the vibro-acoustic behavior of the system, (ii) hides the influence of the earcanal wall vibration distribution, and (iii) could blur the interpretation of the occlusion effect. This paper analyzes, illustrates, and interprets the vibro-acoustic behavior of the open and occluded earcanal using an improved finite element model of an outer ear in conjunction with an associated electro-acoustic model developed in this work. The two models are very complementary to dissect physical phenomena and to highlight the influence of the earcanal wall vibration distribution, characterized here by its curvilinear centroid position, on the occlusion effect.

中文翻译：

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骨传导刺激引起的客观闭塞作用的低频基本机制的理论研究。

由骨传导刺激引起的客观阻塞效应是指由于阻塞耳道开口而导致的低频声压增加。通常将这种现象解释为：骨传导的声音通过耳道开口“泄漏”并被闭塞装置“捕获”。这种本能的解释歪曲了与耳道阻抗增加有关的阻塞效应的基本机制，并且已经被现有的电声模型所强调。然而，这些模型将耳道壁的振动（即现象的根源）简化为体积速度源，作者认为这（i）妨碍了对系统的振动声行为的详尽理解，（ii ）隐藏了耳道壁振动分布的影响，（iii）可能会模糊对遮挡效果的解释。本文使用改进的外耳有限元模型以及在这项工作中开发的相关电声模型，分析，说明和解释了开放式耳道和闭塞型耳道的振动声行为。这两种模型在解剖物理现象和突出耳道壁振动分布（此处以曲线的质心位置为特征）对咬合效应的影响方面非常互补。