Title: Complex modulus of round window membrane over auditory frequencies in normal and otitis media chinchilla ears

Authors: Xuelin Wang; Don Nakmali; Rong Z. Gan

Addresses: School of Aerospace and Mechanical Engineering and Bioengineering Center, University of Oklahoma, Norman, OK 73019, USA ' School of Aerospace and Mechanical Engineering and Bioengineering Center, University of Oklahoma, Norman, OK 73019, USA ' School of Aerospace and Mechanical Engineering and Bioengineering Center, University of Oklahoma, Norman, OK 73019, USA

Abstract: To better reveal the mechanical properties of round window membrane (RWM) in normal and pathological ears, the complex modulus of chinchilla RWM was determined by measuring its dynamic behaviour together with the finite element simulation. The acute otitis media (AOM) was created by transbullar injection of Haemophilus influenzae in chinchillas and RWM specimens in AOM ears were prepared four days post inoculation. Vibration of the RWM induced by coil-magnet force stimulation was measured by laser Doppler vibrometry over frequencies of 0.2-8 kHz. A finite element model-based inverse-problem solving method was used to determine the complex modulus of each RWM specimen in the frequency domain. Experimental results of the AOM ears indicated that the resonance frequency decreased by 13.94% compared with the normal ears and the mean storage modulus and loss modulus were decreased by 65% and 32%, respectively.

Keywords: round window membrane; RWM; complex modulus; viscoelasticity; acute otitis media; finite element method; FEM; modelling; auditory frequencies; chinchilla ears; mechanical properties; simulation; Haemophilus influenzae; vibration; chinchillas.

DOI: 10.1504/IJECB.2015.067680

International Journal of Experimental and Computational Biomechanics, 2015 Vol.3 No.1, pp.27 - 44

Received: 31 May 2014
Accepted: 01 Sep 2014
Published online: 18 Mar 2015 *