Dynamic behavior of the human middle ear: A finite-element method (FEM) analysis

A few investigations of finite-element method (FEM) application to the analysis of the middle ear have already been reported [Funnell et al., J. Acoust. Soc. Am. 81, 1851–1859 (1987); K. R. Williams and T. H. J. Lesser, Br. J. Audiol. 24, 319–327 (1990)]. However, in the models of these studies, ossicles and middle ear cavities were neglected, and their effects on the dynamic behavior of the middle ear have not been analyzed. In this study, first, applying the authors’ own FEM program, a three-dimensional FEM model of a human auditory periphery was established. Then, vibration modes and transfer functions of the middle ear were obtained. The following conclusions can be drawn. (1) The vibration mode of the tympanic membrane and ossicles changes considerably due to the elastic ligament support of the ossicles. (2) This change enables the transfer function of the middle ear to keep flat. (3) The effect of the cavities on the dynamic behavior of the middle ear is large; the amplitude of the tympanic membrane vibration after opening the cavities is nearly two times larger than that before opening them. [Work supported by Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists.]