Cochlear Implant Electrode Mapping for Low-Frequency Stimulation
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Solution Overview
Problem
Cochlear implants often fail to provide effective electrical stimulation for lower frequencies due to the limited insertion depth of electrode arrays, leading to a mismatch between expected and delivered frequencies, and longer arrays risk damaging the cochlea.
Innovation Solution
A cochlear implant design with a flexible electrode array biased to a snail-like shape and two ground electrodes, one external and one apical, allowing for deeper insertion and mapping electrical stimulation to different cochlear locations using both ground electrodes to stimulate lower frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the electrode array is made longer to reach deeper into the cochlea and stimulate lower frequencies, then the frequency range coverage is improved, but the risk of damaging cochlear structures during insertion increases and the insertion difficulty increases
Solution Approach 1:
The invention divides the ground return path into two separate ground electrodes: an apical ground electrode positioned near the apex of the cochlea and a basal ground electrode positioned near the base. This segmentation allows the electrode array to be shorter while still achieving deep cochlear stimulation by routing current through the apical ground electrode, thereby reducing insertion risk while maintaining frequency range coverage.
2Adaptability or versatility
If the electrode array is made longer to stimulate lower frequencies, then the low frequency stimulation capability is improved, but the insertion difficulty increases
Solution Approach 1:
The apical ground electrode serves as an intermediary element that enables low frequency stimulation without requiring a longer electrode array. By positioning the ground electrode at the apex and using it as the return path for current from more basal electrode contacts, the system achieves deep cochlear activation with a shorter, easier-to-insert array.
3Device complexity
If a single ground electrode external to the cochlea is used, then the device simplicity is maintained, but the ability to stimulate lower frequencies is limited
Solution Approach 1:
The ground return path is segmented into two spatially separated ground electrodes: one at the apex and one at the base of the cochlea. This segmentation creates additional current pathways that enable low frequency stimulation while maintaining relatively simple device architecture. The dual-ground configuration adds minimal complexity compared to the significant gain in frequency range capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances sound quality and speech-in-noise performance by accurately stimulating lower frequencies without increasing physical electrode array length, reducing the risk of cochlear damage.
Implementation Method 1
Each of the electrode contacts on the array stimulates a different part of the cochlea and therefore, due to the tonotopic organization of the cochlea, provides a different pitch
Data Source
AI summary
A cochlear implant includes an electrode array having a plurality of electrode contacts arranged along at least a portion of a length of an electrode array, and a processing arrangement configured to map at least one electrode contact to first and/or second mappings. The first mapping provides a first electrical stimulation from the electrode contact to a first ground electrode positioned external to a patient's cochlea to stimulate hearing at a first location in the cochlea positioned adjacent to the electrode contact when the implant is inserted into the cochlea. The second mapping provides a second electrical stimulation from the electrode contact to the second ground electrode to stimulate hearing at a location in the cochlea positioned further towards the apex of the cochlea as compared to a distal end of the electrode array when the implant is inserted into the cochlea.