Effects of individual differences in size and mobility of the middle ear on hearing

Abstract

The size of the tympanic membrane and ossicles and the stiffness of the middle-ear ligaments and joint are different between individuals, and the effects of these differences on middle-ear transfer function have not been clarified. In this study, using finite-element middle-ear models, the effects of individual differences in the size and mobility of the middle ear on its transmission characteristics were analyzed. The individual differences in the size of the normal middle ear were found to affect the transfer function by up to 10 dB. The effects of the Young's moduli of the stapedial annular ligaments and the incudostapedial joint on the transfer function were large compared to the effects of the Young's moduli of the other parts of the middle ear. Copyright © 2006 by The Japan Society of Mechanical Engineers.