Frequency-Modulated DPOAE Measurement for Hearing Threshold Accuracy

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Solution Overview

Problem

The fine structure of Distortion Product Otoacoustic Emissions (DPOAE) interferes with measurement accuracy and reproducibility, particularly in newborn hearing screening and diagnostic tests, causing errors in estimating hearing thresholds and extending test time due to its variability and interference with measurement signals.

Innovation Solution

The method employs frequency-modulated primary tones to compensate for fine structure effects at the cochlear level, using quadrature demodulation and statistical analysis to detect DPOAE signals, thereby reducing the impact of fine structure interference and improving measurement accuracy and reproducibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional DPOAE measurement methods are used, then the measurement process is simple, but measurement precision is degraded due to fine structure interference

Engineering Contradiction:

ImproveDPOAE measurement accuracyVSAvoidmeasurement system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies frequency modulation to the primary tones as a parameter change technique. By modulating the frequency of the primary tones and analyzing the resulting frequency-shifted DPOAE components, the fine structure variations are averaged out across multiple frequency positions, thereby improving measurement precision without requiring complex additional hardware

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs periodic frequency modulation of the primary tones and uses periodic analysis through Fourier transforms to separate the DPOAE signal from fine structure interference. The periodic nature of the modulation allows systematic separation of signal components in the frequency domain

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If high frequency resolution is used to detect DPOAE, then detection capability is improved, but fine structure effects become more prominent and interfere with measurement

Engineering Contradiction:

ImproveDPOAE detection capabilityVSAvoidfine structure interference

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent transforms the static measurement approach into a dynamic one by frequency-modulating the primary tones during measurement. This dynamic approach causes the DPOAE frequency to shift with the primary tone frequencies, allowing the system to sweep through different frequency regions and average out fine structure effects while maintaining high detection capability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent converts the harmful fine structure variations into a beneficial averaging effect. By deliberately frequency-modulating the primary tones and analyzing DPOAE across the entire modulated frequency range, the method transforms fine structure interference into a mechanism that averages out local variations, thereby improving measurement reliability

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If fine structure is present in DPOAE measurements, then measurement time is extended due to repeated testing, but measurement accuracy is also compromised

Engineering Contradiction:

Improvemeasurement reproducibilityVSAvoidtest time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent incorporates feedback through statistical evaluation of the frequency-modulated DPOAE measurements. By analyzing the distribution of DPOAE amplitudes across different frequency positions and using statistical criteria to determine passage/failure, the system achieves reliable measurements without requiring repeated testing, thereby reducing time loss while maintaining high reproducibility

Inventive Principle:

Principle #23Feedback

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 accurate and reproducible DPOAE measurements by eliminating fine structure at the source, enhancing the detection of DPOAE signals and reducing errors in hearing threshold estimation, thus shortening test times and improving diagnostic reliability.

Implementation Method 1

The mechanical activity of the OHC is non-linear, causing non-linear distortion to be produced in the inner ear

Methodology Applied

Scientific EffectNon-linear mechanical activity:

Implementation Method 2

The method employs frequency-modulated primary tones to compensate for fine structure effects at the cochlear level

Methodology Applied

Scientific EffectFrequency modulation: Phase Modulation

Implementation Method 3

using quadrature demodulation and statistical analysis to detect DPOAE signals

Methodology Applied

Scientific EffectQuadrature demodulation: Homodyne Detection

Data Source

PatentUS9232913B2Method and apparatus for measuring distortion product otoacoustic emissions (DPOAE) by means of frequency modulated stimuli

Publication Date: 2016.01.12 PATH MEDICAL

AI summary

A method to reduce DPOAE fine structure in the measurement of DPOAE acoustic signals generated in the cochlea in response to two primary tones.