Hearing Aid RECD Estimation Using Built-in Feedback Path
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Solution Overview
Problem
Existing methods for fitting hearing aids to individual users require external measurement systems and additional adaptors, which can be cumbersome and inaccurate, especially in determining the real-ear-to-coupler-difference (RECD) and effective vent size.
Innovation Solution
A method using existing components of the hearing aid, such as an on-board feedback manager and stored data, to estimate the user's individual RECD and effective vent size, potentially without the need for external equipment or adaptors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external measurement systems and additional adaptors are used to measure RECD and vent size, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The hearing aid uses its own built-in microphone and speaker to perform RECD measurements without requiring external measurement equipment. The device measures its own acoustic characteristics by playing test tones through its speaker and recording the output with its microphone, thereby serving its own measurement needs
Solution Approach 2:
The built-in microphone and speaker are used for multiple purposes: both for normal hearing aid operation and for RECD measurement. This multi-functionality eliminates the need for separate dedicated measurement equipment, reducing overall system complexity while maintaining measurement capability
2Measurement precision
If traditional RECD measurement methods are used with external equipment, then measurement accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The hearing aid autonomously performs measurements using its own components, eliminating the need for clinicians to set up and operate complex external measurement systems. The device automatically plays test tones, records responses, and calculates RECD values
Solution Approach 2:
The system uses feedback from the microphone recording the speaker output to automatically adjust and refine measurements. The measured acoustic response is fed back into the processing system to calculate RECD values and guide fitting decisions
3Device complexity
If existing hearing aid components are used for RECD estimation, then device complexity is reduced, but measurement precision may worsen
Solution Approach 1:
The system replaces traditional mechanical probe tube measurement systems with an electronic/acoustic approach using the hearing aid's own speaker and microphone. Test tones are played through the speaker and the acoustic response is captured and analyzed electronically
Solution Approach 2:
The system measures acoustic parameters (frequency response, resonance frequencies) and uses these to calculate RECD values. By changing from direct pressure measurement to acoustic parameter analysis, the system achieves accurate results using available hearing aid components
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 allows for more precise and user-specific fitting of hearing aids, improving sound pressure levels and reducing feedback, without the need for external measurement systems.
Implementation Method 1
an input transducer for converting input sound to an electric input signal representative of said input sound
Implementation Method 2
an output transducer for providing output sound in dependence on said input sound
Implementation Method 3
measuring a sound pressure level in said residual volume played by said output transducer and propagated via said at least one ventilation channel
Data Source
AI summary
A method of estimating a real-ear-to-coupler-difference (RECD) in a hearing is provided. The hearing aid comprises an input transducer; an output transducer; and an ITE-part configured to define a residual volume when mounted in an ear canal of a user. The method comprises providing an earpiece configured to fit tightly to walls of an ear canal of the user and to provide said residual volume; that the earpiece comprises at least one ventilation channel or opening; a sound outlet allowing sound from said output transducer to be played into said residual volume; characteristics of the at least one ventilation channel or opening; a frequency dependent feedback path estimate from said output transducer to said input transducer through said ventilation channel or opening; and estimating a low-frequency and high frequency RECD values in dependence said feedback path estimate; and determining estimated frequency dependent RECD values in dependence of said estimated low-frequency RECD value, and said estimated high-frequency RECD value.