Hearing Device Sound Processing Using Internal and External Signals
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Solution Overview
Problem
Hearing devices with totally implantable designs face challenges in sound processing due to the presence of non-correlative sounds, such as wind noise and near-field sounds, which can lead to reduced perception of mid- or high-frequency sounds due to amplified low-frequency noise, impairing the recipient's ability to distinguish environmental sounds.
Innovation Solution
A sound processor in the hearing device determines the presence of triggering conditions in the externally-received sound and adjusts the sound signal processing by mixing internal and external sound signals, varying the percentage of each based on the severity of the condition, to generate a processed sound signal that prioritizes spectral components from the internal sound for improved sound perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the external unit processes and amplifies low-frequency sound components, then the recipient can perceive low-frequency sounds, but non-correlative sounds such as wind noise and near-field sounds are also amplified, reducing the recipient's ability to distinguish environmental sounds
Solution Approach 1:
The system dynamically changes the parameter of signal source selection by switching between external and internal microphones based on detected acoustic conditions. When non-correlative sounds are detected in the external signal, the system changes parameters by prioritizing internal microphone input, thereby adapting the low-frequency enhancement function to different acoustic environments and reducing the harmful impact of wind noise and near-field sounds.
Solution Approach 2:
The system employs feedback by continuously analyzing the external sound signal for triggering conditions (non-correlative sounds) and using this analysis to adjust the processing strategy. The detection of high energy in low-frequency bands combined with low correlation between external microphones triggers a feedback loop that switches the system to prioritize internal microphone input, thereby automatically adapting to reduce the impact of harmful sounds.
2Loss of information
If the external unit is used as the primary sound source, then the recipient receives environmental sounds, but skin and other tissue between the internal unit and the acoustic environment reduce the quality of sounds received at the internal unit
Solution Approach 1:
The system implements dynamic adaptability by switching between static operating modes (external-primary and internal-primary) based on real-time acoustic condition analysis. This dynamic adjustment allows the system to optimize sound quality by selecting the appropriate microphone source depending on whether non-correlative sounds are present, thereby compensating for the tissue interference that affects internal microphone performance in certain acoustic environments.
Solution Approach 2:
The system changes the operational parameter of sound source selection between external and internal microphones. By detecting triggering conditions in the external signal, the system dynamically adjusts which microphone serves as the primary source, thereby optimizing sound quality and minimizing the impact of tissue interference on internal microphone reception in challenging acoustic conditions.
3Reliability
If the system switches between using external and internal sound signals based on triggering conditions, then sound perception is improved, but the device complexity increases
Solution Approach 1:
The system segments the acoustic environment into distinct operational zones by defining specific triggering conditions (high low-frequency energy combined with low inter-microphone correlation). This segmentation allows the complex switching logic to be organized into discrete, manageable decision rules rather than continuous complex processing, thereby improving sound perception through conditional switching while keeping the processing logic structured and manageable.
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
This approach enhances sound perception by reducing the impact of noise from non-correlative sounds, ensuring that the recipient can better perceive a wider range of frequencies, thereby improving the overall sound representation and quality in challenging acoustic environments.
Implementation Method 1
The external unit may then send to the internal unit (e.g., via an inductive link) the external sound signal
Implementation Method 2
The external unit may receive at two or more external microphones (or other audio transducers) the sound from the acoustic environment. Each external microphone may similarly provide an external sound signal component
Data Source
AI summary
Disclosed herein are methods, systems, and devices for mitigating the impact of noise, such a low-frequency noise caused by wind, on sounds received at a hearing prosthesis. An example method includes receiving an external sound signal transduced externally to a recipient from an ambient sound and an internal sound signal transduced internally to the recipient from the ambient sound. The example method also includes determining that a triggering condition is present in the external sound signal. The triggering condition may be indicative of a condition in that more adversely affects externally-received sounds than internally-received sounds. In response to determining that the triggering condition is present in the external sound signal, the example method further includes generating a stimulation signal that is based at least in part on spectral information of the internally-transduced sound.