Predictions of middle-ear and passive cochlear mechanics using a finite element model of the pediatric ear

Abstract

A finite element (FE) model was developed based on histological sections of a temporal bone of a 4-year-old child to simulate middle-ear and cochlear function in ears with normal hearing and otitis media. This pediatric model of the normal ear, consisting of an ear canal, middle ear, and spiral cochlea, was first validated with published energy absorbance (EA) measurements in young children with normal ears. The model was used to simulate EA in an ear with middle-ear effusion, whose results were compared to clinical EA measurements. The spiral cochlea component of the model was constructed under the assumption that the mechanics were passive. The FE model predicted middle-ear transfer functions between the ear canal and cochlea. Effects of ear structure and mechanical properties of soft tissues were compared in model predictions for the pediatric and adult ears. EA responses are predicted to differ between adult and pediatric ears due to differences in the stiffness and damping of soft tissues within the ear, and any residual geometrical differences between the adult ear and pediatric ear at age 4 years. The results have significance for predicting effects of otitis media in children.

Fluid-Structure Finite-Element Modelling and Clinical Measurement of the Wideband Acoustic Input Admittance of the Newborn Ear Canal and Middle Ear

“…Stinson et al 1982;Stinson 1985a, b;Gilman and Dirks 1986;Stinson and Khanna 1989;Bergevin and Olson 2014;Khaleghi and Puria 2017). Wang et al (2016) simulated the effects of the compliant canal on the energy absorbance response, but they did not report the pressure distribution within the canal and middleear cavity. Since the ear canal is longer in adults (~25 mm (Anson and Donaldson 1992, p. 146)) than in newborns (~16 mm from the entrance to the umbo, in our model), the onset of standing waves happens at lower frequencies in adult canals.…”

Measurement of Wideband Absorbance as a Test for Otosclerosis

“…The changes are the greatest in the low-frequency region, where middle ear impedance is dominated by stiffness [ 4 ]. Effects of otosclerosis can be understood by examining electric equivalent circuit models of the middle ear [ 5 ] or finite-element models [ 6 , 7 , 8 ]. Traditional low-frequency tympanometry can sometimes reveal changes in middle ear admittance due to otosclerosis (e.g., a decrease in static compliance), but in a significant percentage of cases the compliance of otosclerotic ears remains normal [ 9 ].…”

Maturation of middle ear transmission in children

“…Sound transmission through the middle ear undergoes developmental changes throughout infancy (Hunter et al, 2015; Keefe and Levi, 1996; Keefe et al, 1993; Sanford and Feeney, 2008; Werner et al, 2010) and continues into childhood (Beers et al, 2010; Hunter et al, 2008; Okabe et al., 1988; Wang et al, 2016). Maturation of the middle ear transmission has important implications for perceptual and physiologic studies of auditory development.…”