Hearing Instrument Fitting via Loudness Interpolation
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Solution Overview
Problem
Current hearing instrument fitting procedures require a large number of measurements, making them lengthy and cumbersome for both patients and audiologists, as they need to determine individual gain functions at multiple frequencies and loudness levels.
Innovation Solution
The method involves measuring perceived loudness at a higher frequency resolution for an intermediate loudness level, allowing for interpolation of frequency dependency for low and high loudness levels, reducing the number of measurement points and simplifying the fitting process by separating the frequency and loudness components, which are then used to calculate the individual gain function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional fitting procedures measure loudness contours at multiple frequencies and loudness levels, then individual gain function accuracy is improved, but the number of measurements and procedure length increase
Solution Approach 1:
The patent segments the measurement process into two distinct parts: first measuring loudness contours at only three frequencies (low, middle, high) across multiple loudness levels, then separately estimating the frequency dependency for all intermediate frequencies through interpolation. This segmentation allows reducing measurements from 84 points to just 9 points while maintaining accuracy by treating frequency and loudness dependencies as separable components.
Solution Approach 2:
The patent performs preliminary measurements at a reduced set of frequency points (only 3 frequencies instead of 12) before performing the interpolation step. By establishing the loudness contour shape at these key frequencies first, the subsequent interpolation can accurately estimate the remaining frequency points without requiring additional measurements, thus reducing total measurement time.
2Reliability
If measurements are taken at 12 different frequencies for 7 different loudness levels, then comprehensive hearing loss compensation is achieved, but the fitting procedure becomes lengthy and troublesome
Solution Approach 1:
The patent applies partial action by measuring only at 3 critical frequencies (low, middle, high) rather than all 12 frequencies, while still achieving comprehensive hearing loss compensation through mathematical interpolation. The measurements at these 3 frequencies provide sufficient information to reliably estimate the response at the remaining 9 frequencies, making the procedure simpler without sacrificing reliability.
Solution Approach 2:
The patent changes the measurement parameters from 12 frequencies × 7 loudness levels to 3 frequencies × 7 loudness levels, reducing the measurement burden. The missing frequency information is recovered through interpolation algorithms that estimate the loudness contour shape at intermediate frequencies based on the measured extreme frequencies, maintaining parameter comprehensiveness while reducing measurement complexity.
3Adaptability or versatility
If loudness contours are measured with the hearing instrument worn by the user, then individualized fitting is achieved, but the number of reading points investigated increases to 84
Solution Approach 1:
The patent extracts only the essential measurement information by taking out measurements at just 3 key frequencies instead of all 12 frequencies. The extracted data from these critical frequency points contains sufficient information to reconstruct the complete loudness contour through interpolation, eliminating the need for measurements at the remaining 9 frequency points and reducing procedure complexity while maintaining individualized fitting capability.
Data Source
AI summary
A method for individually fitting a hearing instrument to a user, by: starting operation of the hearing instrument; pre-defining a desired target loudness function perceived by the user defined as function of frequency and input sound pressure level at the microphone; measuring for a given measurement parameter set of perceived loudness levels and frequencies or frequency bands the respective transducer input audio signal level to be applied to the transducer input to achieve the respective perceived loudness level at the respective frequency or frequency band, said measurement parameter set having at least a low, intermediate and high loudness levels, and said intermediate loudness level being measured for a larger number of frequencies or frequency bands and with a finer frequency resolution than said low and high loudness levels; calculating an individual gain function to be implemented in the audio signal processing unit to achieve the pre-defined target loudness function by taking into account the measured transducer input audio signal levels; and operating the hearing instrument with the individual gain function.