Frequency Transposition in EAS Hearing Systems
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Solution Overview
Problem
Existing hybrid Electric Acoustic Stimulation (EAS) systems face a frequency gap between residual acoustic hearing and electrical implant coverage, where patients with impaired hearing lack stimulation in a specific frequency range, leading to incomplete auditory rehabilitation.
Innovation Solution
The implementation of frequency transposition in the EAS system, where a signal processor generates both electrical and acoustic signals to cover this gap, using shallow electrode insertion and selective electrode activation to minimize power consumption and enhance auditory perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency transposition is implemented to bridge the frequency gap, then speech comprehension is improved, but device complexity increases
Solution Approach 1:
The patent introduces an intermediary frequency transposition process that acts as a bridge between the lower acoustic frequency range (processed by hearing aid) and the upper electrical frequency range (processed by cochlear implant). The signal processor transposes frequencies from the upper range down to the lower range, creating an intermediate representation that can be delivered acoustically through the hearing aid, thereby filling the frequency gap without requiring direct electrical stimulation in that range.
2Reliability
If shallow electrode insertion is used to preserve residual hearing, then auditory perception is enhanced, but electrical stimulation coverage is reduced
Solution Approach 1:
The patent addresses the coverage limitation by introducing a frequency dimension transformation. Instead of attempting to cover all frequency ranges electrically (spatial coverage), the system uses frequency transposition to map upper frequency information down to the lower frequency range that is preserved by shallow insertion. This transforms the problem from a spatial coverage issue to a frequency mapping issue, allowing comprehensive frequency coverage through the combination of acoustic and electrical paths.
3Use of energy by moving object
If selective electrode activation is used to reduce power consumption, then energy efficiency is improved, but stimulation effectiveness may be reduced
Solution Approach 1:
The patent extracts the frequency gap coverage function from the electrical stimulation path and assigns it to the acoustic path via frequency transposition. By transposing upper frequency information to the lower frequency range and delivering it acoustically through the hearing aid, the system removes the need for electrical stimulation in the gap region, thereby reducing the number of active electrodes and lowering power consumption while maintaining complete frequency coverage.
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
Frequency transposition effectively bridges the frequency gap, improving speech comprehension and reducing power consumption by leveraging residual hearing and targeted electrical stimulation, allowing for more efficient and effective auditory rehabilitation across the entire frequency range.
Implementation Method 1
the fluid-filled cochlea 104 functions as a transducer to generate electric pulses which are sensed by the acoustic nerve 113
Implementation Method 2
the signal processor uses frequency transposition to include the upper subrange in the lower subrange
Data Source
AI summary
An electric acoustic stimulation (EAS) hearing system includes a signal processor for processing an acoustic signal input to generate: i. an electrical communications signal representative of an upper electrical range of acoustic frequencies, and ii. an acoustic communications signal representative of a lower acoustic range of acoustic frequencies, the acoustic range including: (1) a lower subrange of acoustic frequencies perceivable by the patient with amplification, and (2) an upper subrange of acoustic frequencies not perceivable by the patient, wherein the signal processor uses frequency transposition to include the upper subrange in the lower subrange. An implanted electrical stimulation subsystem receives the electrical communications signal and delivers a corresponding electrical stimulation signal to auditory neural tissue of an implanted patient. An external acoustic stimulation subsystem receives the acoustic communications signal and delivers a corresponding amplified acoustic stimulation signal to the ear canal of the patient.