Cochlear Implant Current DAC Mapping for Wider Effective Dynamic Range
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Solution Overview
Problem
Cochlear implant users face challenges in sound quality due to pitch distortion and intensity discrimination, with limited ability to discriminate intensity levels between 5 and 45, compared to normal individuals who can discriminate between 50 and 200.
Innovation Solution
A method for improving neural stimulation in cochlear implants by setting a target range between a T level and a C level for stimulation current, mapping current levels within this range using a reconfigurable current DAC, and utilizing a neural stimulation IC chip with a clock & data recovery block, back telemetry block, neural stimulator, and digital controller to control stimulation pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the total number of current levels is increased to improve intensity discrimination, then sound quality improves, but device complexity and hardware overhead increase
Solution Approach 1:
The patent applies dynamic range compression by making the current level distribution adaptive rather than fixed. The system dynamically adjusts the mapping between digital codes and current levels based on the user's hearing profile, concentrating current levels within the effective dynamic range (between T level and C level) to maximize discrimination capability without requiring a fixed increase in total current levels.
Solution Approach 2:
The patent changes the parameter distribution by transforming the uniform current level distribution into a non-uniform distribution that concentrates levels within the effective dynamic range. This is achieved through mapping functions that adjust current levels based on user-specific hearing characteristics, thereby improving intensity discrimination without proportionally increasing the total number of current levels.
2Ease of manufacture
If current levels are uniformly distributed across the full range, then hardware implementation is simple, but intensity discrimination is poor within the effective dynamic range
Solution Approach 1:
The patent applies local quality by making the current level distribution non-uniform within the effective dynamic range. Instead of uniform distribution, the system concentrates current levels within the range between T level and C level, creating a localized high-density region where discrimination is most needed. This is achieved through mapping functions that adjust current levels based on user-specific hearing characteristics.
Solution Approach 2:
The system dynamically adjusts the current level mapping based on the user's hearing profile rather than using a fixed uniform distribution. The mapping function adapts the current levels to concentrate them within the effective dynamic range, thereby improving discrimination where it matters most while maintaining hardware simplicity.
3Adaptability or versatility
If more current levels are allocated outside the effective dynamic range, then the overall current range is expanded, but the resolution within the effective range is reduced
Solution Approach 1:
The patent applies partial action by focusing current level allocation on the effective dynamic range (between T level and C level) rather than uniformly across the full range. The system deliberately concentrates current levels within the effective range where they are needed for discrimination, rather than distributing them excessively across the entire range including regions outside the effective dynamic range.
Solution Approach 2:
The system changes the parameter distribution by transforming uniform current level allocation into a concentrated distribution within the effective dynamic range. The mapping function adjusts current levels to maximize resolution within the effective range, thereby improving discrimination performance without requiring excessive allocation of current levels outside this critical range.
Data Source
AI summary
The present disclosure discloses a method for improving an effective dynamic range including acquiring a hearing profile of a user, setting a section between a T level and a C level as a target range of a stimulation current for each of a plurality of electrodes included in an electrode array of a cochlear implant system based on the hearing profile, and mapping a plurality of current levels to an output current within the target range.