Directional Acoustic Fitting for Hearing Aids
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Solution Overview
Problem
Current hearing aid technologies and fitting systems fail to effectively enhance signal-to-noise ratios, diminish sound direction perception, and do not adequately compensate for loudness recruitment, leading to difficulties in understanding speech in noisy environments and requiring increased signal-to-noise ratios, which can result in discomfort and reduced user satisfaction.
Innovation Solution
The integration of near instantaneous head azimuth detection and measurement during the hearing aid fitting process, allowing for precise modification of sound channel information and programming to coordinate directional hearing cues, thereby improving signal-to-noise ratios and compensating for loudness recruitment, allowing users to better localize sounds across a range of frequencies and intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hearing aids amplify sounds to improve hearing threshold, then speech understanding improves, but directional information becomes smeared and sound localization ability deteriorates
Solution Approach 1:
The hearing aid system segments the audio signal into multiple frequency channels (at least two channels) and processes directional information separately for each channel. This segmentation allows the system to preserve directional cues in each frequency band while providing amplification, rather than processing all frequencies as a single mixed signal which would smear directional information.
Solution Approach 2:
The system applies different processing characteristics to different frequency channels, with each channel having its own directional processing parameters. This local quality approach ensures that directional information is preserved in the specific frequency regions where it is most important for localization, while still providing appropriate amplification for hearing threshold improvement.
2Measurement precision
If hearing aids provide broad amplification across all frequencies, then overall hearing sensitivity improves, but signal-to-noise ratio in noisy environments deteriorates
Solution Approach 1:
The system divides the audio spectrum into multiple frequency channels and applies different gain and noise processing to each channel. This segmentation enables the hearing aid to amplify speech frequencies while applying more aggressive noise reduction in frequency bands where background noise predominates, thereby improving the signal-to-noise ratio in noisy environments while maintaining overall hearing sensitivity.
3Measurement precision
If hearing aids increase amplification gain to compensate for hearing loss, then speech understanding improves, but loudness discomfort and user dissatisfaction increase
Solution Approach 1:
The system applies different amplification gains to different frequency channels based on the user's specific hearing thresholds for each frequency. This local quality approach ensures that amplification is precisely tailored to the user's hearing needs in each frequency region, providing sufficient gain for speech understanding while avoiding excessive amplification that would cause loudness discomfort. The directional processing further refines this by ensuring that amplified signals maintain their spatial characteristics.
Solution Approach 2:
The system incorporates feedback mechanisms where the processed output from each frequency channel is monitored and used to adjust processing parameters. This feedback loop allows the hearing aid to adapt to the user's real-time listening conditions and comfort levels, reducing loudness discomfort while maintaining speech understanding by dynamically adjusting amplification and directional processing based on actual performance.
Data Source
AI summary
Hearing aids and a method of acoustically fitting the hearing aids comprises providing a plurality of audible tones, each having a predetermined frequency through a pair of hearing aids being worn by a patient. The tones are provided at specific sound pressure in each ear. The patient changes the relative sound pressure in each ear until a perceived direction of source of the tone is in front of the patient. The amplification or attenuation requirements of a hearing aid are modified based on the difference in the sound pressures required for the left and right ears of the patient for perceived directional sameness for each frequency band-pass channel.