Transmodiolar Electrode Array for Cochlear Implant Spatial Specificity
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Solution Overview
Problem
Existing cochlear implant systems face challenges in achieving spatially high-resolution electrical stimulation due to the diffusion of stimulating current and the distance between the electrode array and the spiral ganglia, leading to low specificity and potential damage from current application.
Innovation Solution
A transmodiolar electrode array is placed within the modiolus of the cochlea, reducing the distance to the spiral ganglia and using a stiffer, more densely packed electrode design with higher Young's modulus than conventional arrays, allowing for direct stimulation of the auditory nerve and minimizing current interactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional electrode array is inserted into the scala tympani, then the insertion procedure is easier and the array can be placed without complex surgical procedures, but the distance between the electrode and the spiral ganglia increases, reducing spatial specificity of stimulation
Solution Approach 1:
Instead of inserting the electrode array into the scala tympani (conventional approach), the patent inverts the approach by inserting the array through the modiolus (central axis) of the cochlea. This allows the electrodes to be positioned directly adjacent to the spiral ganglia, achieving high spatial specificity while maintaining a feasible surgical procedure through the round window niche.
2Object-affected harmful factors
If the electrode array is placed farther from the spiral ganglia, then the current diffusion is reduced, but the spatial specificity of stimulation decreases and more current is required, increasing risk of damage
Solution Approach 1:
The patent applies local quality by creating a steep current gradient through the modiolus bone. The bone acts as a natural barrier that confines current flow locally to the region immediately surrounding the electrode, preventing lateral diffusion while maintaining high spatial specificity. This allows effective stimulation with lower current levels.
3Measurement precision
If a higher number of electrodes with higher density is implemented, then the spatial resolution of stimulation is improved, but the manufacturing complexity and difficulty of precise positioning increase
Solution Approach 1:
The patent segments the electrode array into multiple independently controllable electrodes along the insertion direction, with each electrode capable of being activated separately. This segmentation enables high spatial resolution stimulation while the modular design simplifies manufacturing and positioning, as each segment can be precisely controlled and adjusted independently.
4Measurement precision
If the electrode array is positioned closer to the spiral ganglia, then the spatial specificity is improved, but the risk of damage from current application to the delicate neural structures increases
Solution Approach 1:
The patent uses the modiolus bone as an intermediary medium between the electrode and the spiral ganglia. The bone provides a protective barrier that prevents direct contact and potential damage to the delicate neural structures, while still allowing effective electrical stimulation to reach the spiral ganglia through the bone's conductive properties.
Data Source
AI summary
According to an embodiment, an electrode array for a transmodiolar implant is disclosed. The implant includes a substrate, a conductive metal located at a plurality of discrete portions on the substrate; and a single layer of insulation material over the conductive metal and the substrate. The single layer of insulation material includes a plurality of apertures that expose the conductive metal, the exposed conductive metal forming a plurality of electrodes, wherein stiffness of the electrode array is adapted to allow insertion of the electrode array into a modiolus of a subject.