A sweep frequency equalization threshold noise test method for rapid detection of cochlear dead zone

Abstract

The invention relates to the field of noise detection technology, in particular to a swept frequency equalization threshold noise test method for rapid detection of cochlear dead zones, which can measure continuous dead zone results in a large range, solve the problem of isolated test frequency and easy omission of dead zones, and can accurately detect the edge frequency of the dead zone, continuously play the equalization threshold noise, and realize the feedback of hearing or not hearing by continuously pressing or releasing a button, when the subject presses the button, the intensity of the pure tone continuously decreases; when the subject releases the button, the intensity of the pure tone continuously increases, and a sawtooth curve whose hearing threshold constantly fluctuates when masked by the equalization threshold noise is obtained, and the midpoints of each segment of the sawtooth curve are connected to obtain a test result in one direction, and the signal-to-noise ratio of the hearing threshold after masking by the equalization threshold noise is greater than 10dB, and the area where the hearing threshold after masking is 10dB higher than the hearing threshold before masking is determined as the dead zone, and the frequency corresponding to the end point of the curve where the dead zone is located is the edge frequency of the dead zone.

Description

Technical Field

[0001] The present invention relates to the technical field of noise detection, and in particular to a sweep frequency equalization threshold noise testing method for rapid detection of cochlear dead zones. Background Art

[0002] The cochlea is an organ in the human body that converts the mechanical energy of external sound waves into nerve impulses. The round window of the cochlea receives the sound vibrations from the ossicles and causes the basilar membrane to vibrate. Sounds of different frequencies cause the basilar membrane to vibrate in different parts, and the vibration of the basilar membrane drives the hair cells to vibrate and produce hearing. Auditory hair cells are divided into outer hair cells and inner hair cells. The outer hair cells are like amplifiers, which are mainly responsible for amplifying the vibrations caused by sound on the basilar membrane. Their damage will reduce the gain of the cochlear amplifier; while the inner hair cells are like transducers, which mainly convert the vibrations of the basilar membrane into the excitement of the auditory nerve. Their damage will reduce the number of action potentials of the auditory nerve. Usually, sensorineural hearing loss is mainly caused by damage to the outer hair cells. At this time, amplifying the input through hearing aids can enable the patient to hear the sound again. However, in some cases, the inner hair cells or neurons of the auditory nerve in a certain frequency area of ​​the cochlea are severely damaged, resulting in the inability of the patient to hear in this part of the frequency domain no matter how the sound is amplified. This part of the frequency area is called the cochlear dead zone, or simply the dead zone.

[0003] The cochlear dead zone is the area where the inner hair cells or auditory neurons in the cochlea lose their function or almost lose their function. The detection of the cochlear dead zone is of great significance in hearing aid fitting and cochlear implantation. The existing method for detecting the cochlear dead zone: the test results of the equalized threshold noise test (TEN Test) are isolated frequency points, and what is detected is the "dead point" rather than the "dead zone". The tester is not clear whether there is a non-dead zone area between these isolated test points; on the other hand, due to the low frequency accuracy of its test results, the TEN Test cannot provide a more accurate dead zone edge frequency. Summary of the invention

[0004] In order to solve the problems that existing test results lack continuity, easily miss dead zones, and cannot provide more accurate dead zone edge frequencies, the present invention provides a swept frequency equalization threshold noise test method for rapid detection of cochlear dead zones, which can measure continuous dead zone results within a large range, solves the problems of isolated test frequencies and easy missing dead zones, and can accurately detect the edge frequencies of dead zones.

[0005] The technical solution is as follows: a swept frequency equalized threshold noise test method for rapid detection of cochlear dead zones, characterized in that the equalized threshold noise is played continuously, and the subject needs to judge whether he can hear the pure tone with a continuously changing frequency under the noise background, the intensity of the equalized threshold noise is the subject's hearing threshold + NdB at the frequency of the currently played pure tone, the frequency change rate of the pure tone is proportional to the current frequency, and the feedback of hearing or not hearing is achieved by continuously pressing or releasing the button, when the subject presses the button, the pure tone intensity continues to decrease; when the subject releases the button, the pure tone intensity continues to increase, and a sawtooth curve is obtained in which the hearing threshold constantly fluctuates when masked by the equalized threshold noise, and the midpoints of each segment of the sawtooth can be connected to obtain a test result in one direction, and the signal-to-noise ratio of the hearing threshold after masking with the equalized threshold noise is greater than NdB and the area where the hearing threshold after masking is N dB higher than the hearing threshold before masking is judged as a dead zone, and the frequency corresponding to the endpoint of the curve where the dead zone is located is the edge frequency of the dead zone.

[0006] Its further feature is that when the test adopts the swept frequency pure tone, the forward sweep frequency and the reverse sweep frequency are used respectively, and the sawtooth curve obtained by the test is smoothed to obtain a smooth curve, and the smooth curve is averaged on the time axis: first, the two smooth curves are respectively shifted left or right on the time axis by time t, t≤0.1s, and then the final test result is obtained by stacking and averaging, wherein the forward sweep frequency is from low to high frequency, and the reverse sweep frequency is from high to low frequency;

[0007] A further feature is that the time t is taken as the case where the difference between the two test results is the smallest among all the moves;

[0008] The value of N is 10.

[0009] After adopting the present invention, the test subject's "hearing / inaudible" feedback is changed from the original button pressing to continuous pressing or releasing the button, so that a continuous test curve can be obtained, and then the dead zone range is determined based on the comparison of the hearing threshold, so that continuous dead zone results in a large range can be measured, solving the problems of isolated test frequencies and easy omission of dead zones, and at the same time, the edge frequency of the dead zone is accurately detected according to the frequency corresponding to the end point of the curve where the dead zone is located. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the original curve and the smoothed curve of the forward frequency sweep when sweeping pure tone;

[0011] Figure 2 It is a schematic diagram of the original reverse frequency sweep curve and the smoothed curve when sweeping pure tone;

[0012] Figure 3 This is a schematic diagram of the average processed curve. DETAILED DESCRIPTION

[0013] A swept frequency equalized threshold noise test method for rapid detection of cochlear dead zones. The equalized threshold noise is played continuously, and the subject needs to judge whether he can hear a pure tone with a constantly changing frequency against the background of the noise. The intensity of the equalized threshold noise is the subject's hearing threshold at the current playing pure tone frequency + 10dB (frequencies without pure tone audiometry data are filled in using linear interpolation). In order to comply with the psychophysical property that the auditory frequency resolution is consistent with the logarithm of the current frequency, the frequency change rate of the pure tone is proportional to the current frequency. For example, the time it takes for the pure tone frequency to change from 500Hz to 1000Hz is the same as the time it takes for the pure tone frequency to change from 1000Hz to 2000Hz. The same; in order to measure the hearing threshold of the continuous subject when masked by the equalized threshold noise (TEN), the subject's feedback on "hearing or not hearing" is achieved by continuously pressing or releasing the button. When the subject presses the button, the pure tone intensity continues to decrease; when the subject releases the button, the pure tone intensity continues to increase, and a sawtooth curve is obtained in which the hearing threshold constantly fluctuates when masked by the equalized threshold noise. The test result in one direction can be obtained by connecting the midpoints of each segment of the sawtooth. The signal-to-noise ratio of the hearing threshold after masking by the equalized threshold noise (TEN) is greater than 10dB, and the area where the hearing threshold after masking is 10 dB higher than the hearing threshold before masking is judged as the dead zone, and the frequency corresponding to the endpoint of the curve where the dead zone is located is the edge frequency of the dead zone.

[0014] When the test uses swept pure tone, there is a certain reaction time between hearing the sound and pressing or releasing the button, so there will be a certain delay between the curve obtained by the test and the actual result. Therefore, forward sweep and reverse sweep are used respectively. The sawtooth curve obtained by the test is smoothed to obtain a smooth curve, and the smooth curve is averaged on the time axis: first, the two smooth curves are shifted left or right on the time axis by time t, t≤0.1s, and then the final test result is obtained by stacking and averaging. The forward sweep is from low to high frequency, and the reverse sweep is from high to low frequency, see respectively. Figure 1 , Figure 2 , Figure 3 As shown in Figure 2, the time t is taken as the case where the difference between the two test results is the smallest among all the movements. The frequency change of the swept pure tone can be adjusted according to the accuracy of the swept tone change.

[0015] The present invention changes the detection of dead points to detection of dead zones, which greatly improves the accuracy of the test and provides accurate results for hearing aid fitting or enables accurate implantation of artificial cochleae.

Claims

1. A sweep frequency equalization threshold noise test method for rapid detection of cochlear dead zone, characterized in that: Balanced threshold noise is played continuously, and the subjects need to judge whether they can hear the pure tone with constantly changing frequency under the noise background. The intensity of the balanced threshold noise is the subject's hearing threshold at the current pure tone frequency + NdB. The frequency change rate of the pure tone is proportional to the current frequency. Feedback of hearing or not hearing is achieved by continuously pressing or releasing the button. When the subject presses the button, the pure tone intensity continues to decrease; when the subject releases the button, the pure tone intensity continues to increase, and a sawtooth curve is obtained in which the hearing threshold constantly fluctuates when masked by the balanced threshold noise. The test result in one direction can be obtained by connecting the midpoints of each segment of the sawtooth. The area where the signal-to-noise ratio of the hearing threshold after masking with the balanced threshold noise is greater than NdB and the hearing threshold after masking is NdB higher than the hearing threshold before masking is judged as the dead zone, and the frequency corresponding to the endpoint of the curve where the dead zone is located is the edge frequency of the dead zone.

2. A sweep frequency equalization threshold noise test method for rapid detection of cochlear dead zone according to claim 1, characterized in that: When the test adopts swept frequency pure tone, forward sweep and reverse sweep are used respectively. The sawtooth curve obtained by the test is smoothed to obtain a smooth curve, and the smooth curve is averaged on the time axis: first, the two smooth curves are respectively shifted left or right on the time axis by time t, t≤0.1s, and then the superposition average calculation is performed to obtain the final test result, where the forward sweep is from low to high frequency, and the reverse sweep is from high to low frequency.

3. A sweep frequency equalization threshold noise test method for rapid detection of cochlear dead zone according to claim 2, characterized in that Time t is the case where the difference between the two test results is the smallest among all moves.

4. A sweep frequency equalization threshold noise test method for rapid detection of cochlear dead zone according to claim 1, characterized in that: The value of N is 10.

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