Virtual Rhesus Labyrinth Model Predicts Responses to Electrical Stimulation Delivered by a Vestibular Prosthesis

Area of Science:

• Biomedical Engineering
• Neuroscience
• Computational Modeling

Background:

• Vestibular implants aim to restore balance sensation after hair cell loss.
• Accurate modeling of prosthetic current spread is crucial for effective implant design.
• The complex anatomy of the inner ear presents challenges for precise modeling.

Purpose of the Study:

• To develop a computational model of the primate labyrinth for simulating prosthetic current spread.
• To investigate the impact of electrode placement on vestibular afferent activity.
• To optimize electrode array and stimulation protocols for vestibular implant systems.

Main Methods:

• Generated 3D labyrinth geometry from micro-MRI and micro-CT scans of rhesus temporal bones.
• Computed extracellular potential fields using finite element methods for biphasic current pulses.
• Integrated potential fields with dynamic models of 2415 vestibular afferent axons.

Main Results:

• Model accurately predicted 3D vestibulo-ocular reflex (VOR) responses based on simulated afferent activity.
• Electrode placement significantly influenced prosthetic current spread and neural activation.
• Optimal performance predicted when the reference electrode is in the common crus (CC).

Conclusions:

• The developed primate labyrinth model effectively simulates prosthetic stimulation effects.
• Model predictions support improved vestibular prosthesis design through strategic electrode placement.
• Further extension to human anatomy will aid clinical application of vestibular implants.