Fitting pole-zero micromechanical models to cochlear response measurements.

Area of Science:

• Auditory Neuroscience
• Biophysics
• Mechanical Engineering

Background:

• The cochlea's linear micromechanical response is efficiently described by poles and zeros.
• Pole-zero models offer a framework for understanding cochlear mechanics.

Purpose of the Study:

• To develop and optimize pole-zero models for the coupled cochlea.
• To compare the fitting accuracy of one- vs. two-degree-of-freedom models to experimental data.

Main Methods:

• Derived pole-zero models with local scaling symmetry for 1 and 2 degree-of-freedom systems.
• Optimized a coupled cochlea model to minimize differences with basilar membrane measurements.
• Evaluated models at various excitation levels, including active and passive cochlear states.

Main Results:

• A two-degree-of-freedom micromechanical model generally provided a better fit than a single-degree-of-freedom model.
• The best fit was achieved with a two-degree-of-freedom model incorporating 3D fluid coupling.
• Model performance varied between active (low excitation) and passive (post-mortem) cochlear conditions.

Conclusions:

• Two-degree-of-freedom models, especially with 3D fluid coupling, better represent cochlear micromechanics.
• Fitted model parameters provide insights into the properties of lumped parameter networks for cochlear modeling.