Sparse Switch Network for Simultaneous Neural Stimulation
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Solution Overview
Problem
Current tissue-stimulating prostheses, such as cochlear implants, face challenges in delivering targeted electrical stimulation due to high voltage compliance requirements, which lead to large and costly IC devices, and traditional sequential monopolar stimulation results in significant neural population overlap, reducing precision in hearing outcomes.
Innovation Solution
The implementation of a sparse switch network that connects each current source to multiple electrodes and each electrode to a subset of current sources, preventing adjacent electrodes from sharing the same source, enabling simultaneous stimulation with reduced hardware size and power consumption, allowing for focused stimulation patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sequential monopolar stimulation is used, then the device structure is simple, but neural population overlap is significant, reducing precision in hearing outcomes
Solution Approach 1:
The electrode array is segmented into multiple independently controllable electrodes, allowing selective stimulation of specific electrode groups. This segmentation enables precise control over which electrodes are activated simultaneously, reducing neural population overlap while maintaining manageable device complexity through systematic electrode grouping and control.
2Reliability
If high voltage compliance is used to deliver electrical stimulation, then stimulation effectiveness is improved, but IC device size and cost increase
Solution Approach 1:
Multiple current sources are merged into a single integrated current source that can selectively drive different electrode groups. This consolidation reduces the overall IC device size and component count while maintaining the ability to deliver effective high voltage compliance stimulation through coordinated activation of multiple electrodes from the unified current source.
Solution Approach 2:
The current source is designed with multi-functionality to serve multiple electrode groups sequentially and simultaneously. By creating a universal current source that can adaptively connect to different electrode combinations, the device achieves effective stimulation across multiple targets without requiring separate dedicated current sources for each electrode, thereby reducing IC size.
3Measurement precision
If multiple current sources are used to enable simultaneous stimulation, then stimulation precision is improved, but device power consumption and complexity increase
Solution Approach 1:
Multiple current sources are merged into a single multi-functional current source that can selectively drive different electrode groups. This consolidation reduces the total power consumption associated with multiple independent current sources while maintaining the precision of simultaneous stimulation through coordinated electrode activation from the unified source.
Data Source
AI summary
Presented herein are implantable medical devices, such as tissue-stimulating prostheses, that are configured to deliver simultaneous stimulation to a recipient. In one embodiment, a tissue stimulating prosthesis comprises a plurality of current sources, a plurality of electrodes (e.g., a linear array of electrodes), and a hardwired electrical network of switches, sometimes referred to herein as a “sparse switch network.” The sparse switch network is configured to connect each of the current sources to more than one of the electrodes, and to connect each of the electrodes to only a subset of the current sources. The sparse switch network is configured to prevent adjacent electrodes from being connected to the same current source.