Vibro-acoustic modelling of the outer and middle ear using the finite-element method

Area of Science:

• Biomechanics
• Computational Auditory Physiology
• Medical Device Engineering

Background:

• Understanding the ear's complex dynamics is crucial for developing effective treatments for hearing loss.
• Ossicular replacement prostheses aim to restore auditory function but their precise mechanical impact requires detailed analysis.

Purpose of the Study:

• To predict the forced-frequency response of the ear using finite-element analysis.
• To investigate the dynamic behavior of the tympanic membrane and ossicles with and without a prosthesis.
• To validate the model against experimental data.

Main Methods:

• A three-dimensional finite-element model of the ear was developed, incorporating ligaments, muscles, and damping effects.
• The model simulated the forced-frequency response, analyzing translation and rotation of the stapedial footplate.
• Model predictions were validated by comparing with experimental measurements of umbo displacement.

Main Results:

• Translatory motion of the stapedial footplate generally decreases with increasing frequency, with exceptions at natural frequencies.
• Stapedial footplate tilting motion is frequency-dependent.
• The presence of an ossicular replacement prosthesis significantly alters the dynamical response by shifting natural frequencies.

Conclusions:

• Finite-element analysis provides a powerful tool for visualizing and predicting the ear's dynamic behavior.
• Prostheses substantially modify the mechanical properties of the middle ear, impacting sound conduction.
• Further research can refine these models for improved prosthesis design and surgical outcomes.