DPOAE Hearing Test Pulse Pair Sequencing
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Solution Overview
Problem
Current methods for determining auditory thresholds using distortion product otoacoustic emissions (DPOAEs) are excessively time-consuming, making them unsuitable for clinical use, especially for hearing-impaired patients, and often result in unsatisfactory accuracy in measuring growth curves and threshold values.
Innovation Solution
A method involving the use of multiple pulse pairs with different excitation frequencies presented at staggered intervals, combined with adaptive stimulation and analysis, allows for the measurement of growth curves for multiple frequencies within a short time frame while suppressing artifacts and improving signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods are used to measure DPOAE growth curves, then measurement accuracy is maintained, but measurement time becomes excessively long
Solution Approach 1:
The patent segments the measurement process by dividing it into multiple measurement blocks, each containing a specific sequence of pulse pairs with different frequency ratios. This allows parallel measurement of multiple frequencies while maintaining adequate signal-to-noise ratio through repeated presentations, thereby reducing total measurement time without sacrificing accuracy
Solution Approach 2:
The patent employs periodic pulsed stimulation instead of continuous stimulation, presenting pulse pairs at specific intervals with defined duty cycles. This periodic action allows the cochlear amplifier to recover between stimuli while accumulating sufficient signal energy through temporal averaging, achieving both speed and accuracy
2Productivity
If measurement speed is increased by using fewer presentation repetitions, then measurement time is reduced, but signal-to-noise ratio deteriorates
Solution Approach 1:
The patent merges measurements across multiple frequency ratios by presenting them in an interleaved sequence within the same measurement blocks. The DPOAE responses at different frequency ratios are recorded simultaneously and processed together, allowing the system to achieve adequate signal-to-noise ratio for multiple frequencies without requiring separate measurement sessions for each frequency
Solution Approach 2:
The patent maintains continuous useful action by systematically varying the frequency ratio across measurement blocks rather than completing all measurements at one frequency ratio before moving to the next. This continuous variation ensures that measurement time is efficiently utilized across all required frequencies while maintaining adequate averaging for each frequency point
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 significantly reduces measurement time, enabling the estimation of auditory thresholds with a standard deviation of 3 to 4 dB and accuracy within 10 dB, making it clinically viable for assessing hearing function.
Implementation Method 1
The methods are based upon the measurement of distortion products of otoacoustic emissions (DPOAE's) that are generated by pairs of excitation signals
Implementation Method 2
This age-related hearing loss is dominated by an impairment of the so-called cochlear amplifier (the mechanical amplification of the traveling wave in the cochlea) in the inner ear, which amplifier in the healthy condition achieves an amplification of the vibration in the inner ear by the factor 300 to 1000 through a complex interplay of electro-mechano-biochemical mechanisms
Implementation Method 3
Pulse pairs comprising a first pulse of the first excitation signal and a second pulse of the second excitation signal are presented in the ear, and the DPOAE's evoked thereby are detected and evaluated
Data Source
AI summary
In a method for examining the faculty of hearing for at least one ear of a mammal, in which growth curves are determined on the basis of the measurement of DPOAE's evoked by pairs of excitation signals (f1, f2) for different excitation frequencies f2, the ear is presented with first excitation signals with a first excitation frequency f1 and a first noise level L1 and secondary excitation signals with a second excitation frequency f2 and a second noise level L2. Pulse pairs with a first pulse of the first excitation signal and a second pulse of the second excitation signal are presented in the ear, and the DPOAE's evoked thereby are captured and evaluated. A set of at least two different pulse pairs with different second excitation frequencies f2 is presented in one block that is repeated several times during a measuring period.