A viscoelastic model for the response of a step change in velocity of the human otolith organs

Abstract

The otolith organs are housed in the inner ear and are responsible for sensing accelerations and gravity. These inertial sensing systems are modeled in this thesis as a three material system consisting of a rigid otoconial plate attached to the skull by a gel layer, surrounded by a viscous endolymph fluid. The gel layer is considered to be a viscoelastic solid, and modeled as a simple Kelvin element. The governing differential equations are derived and nondimensionalized, yielding three nondimensional parameters: nondimensional density, R, nondimensional viscosity, M, and nondimensional elasticity, 6. The equations are solved using uÌ nite difference techniques on a digital computer. By comparing the modelâ s response with previous biological research, values for the nondimensional parameters are found. The value of R is 0.75 and the value of 6 is between 0.3 and 0.075. While the value of M is placed between 5. and 10., results indicate that to properly model the long time response of the otolith, a single and constant value for viscosity is not feasible.