JP7770670B2 - Operating method and program for auditory characteristics measurement system, and auditory characteristics measurement system - Google Patents

Description

The present invention relates to an auditory characteristics measurement method, program, and auditory characteristics measurement system, and in particular to a technology for measuring auditory characteristics by outputting a stimulus sound toward the ear canal of a subject.

Patent Document 1 discloses an auditory threshold estimation device that estimates the auditory threshold used in the Auditory Brainstem Response (ABR) test to confirm the diagnosis of hearing impairment. This test is performed by providing the subject with a sound stimulus to excite the auditory nervous system, and then acquiring and recording six to seven electrical potentials that occur in the brainstem within 10 milliseconds of the sound stimulus via lead electrodes placed on the scalp.

JP 2014-188040 A

The present invention aims to provide an auditory characteristics measurement method, program, and auditory characteristics measurement system that can shorten the time required to measure a subject's auditory characteristics.

To achieve the above object, one embodiment of the present invention provides a hearing characteristic measurement method that includes an output step, a sound receiving step, and an analysis step. In the output step, a stimulus sound that is random noise is output toward the ear canal of the subject. In the sound receiving step, a reflected sound that occurs when the stimulus sound output in the output step is reflected in the ear canal is received. In the analysis step, the reflected sound received in the sound receiving step is frequency analyzed.

Furthermore, to achieve the above-mentioned object, a program according to one embodiment of the present invention causes one or more processors to execute the above-mentioned auditory characteristic measurement method.

In order to achieve the above object, an auditory characteristic measurement system according to one embodiment of the present invention comprises an output unit, a sound receiving unit, and an analysis unit. The output unit outputs a stimulus sound, which is random noise, toward the ear canal of the subject. The sound receiving unit receives a reflected sound generated when the stimulus sound output by the output unit is reflected in the ear canal. The analysis unit performs frequency analysis of the reflected sound received by the sound receiving unit.

The present invention provides an auditory characteristics measurement method, program, and auditory characteristics measurement system that can shorten the time required to measure a subject's auditory characteristics.

FIG. 1 is a schematic diagram showing the configuration of an auditory characteristic measurement system according to an embodiment. FIG. 2 is a schematic diagram showing an M-sequence tone. FIG. 3 is a schematic diagram showing the structure of the human ear. FIG. 4A is a schematic diagram showing the configuration of a cavity for calibration. FIG. 4B is a schematic diagram showing a cavity simulating the ear canal of a subject in a state where the middle ear is not resonating. FIG. 4C is a schematic diagram showing a cavity simulating the ear canal of a subject, in which the middle ear is resonating. FIG. 5 is a diagram showing an SPL (Sound Pressure Level) curve as an adult's hearing characteristic. FIG. 6A is a diagram showing an SPL curve as the hearing characteristic of an adult with normal hearing. FIG. 6B is a diagram showing an SPL curve as the hearing characteristic of a newborn baby with normal hearing. FIG. 7 is an explanatory diagram for explaining the unique characteristics of the external auditory canal of a newborn baby. FIG. 8 is an explanatory diagram for explaining the theoretical values of the SPL curve. FIG. 9 is a diagram showing theoretical values of the SPL curve in the cavity used for calibration. FIG. 10 is a flowchart showing an example of the operation of the hearing characteristic measuring system according to the embodiment. FIG. 11 is a comparison diagram between the measurement results of the auditory characteristic measuring system according to the embodiment and the measurement results of the auditory characteristic measuring system of the comparative example. FIG. 12A is a diagram showing the measurement results of the auditory characteristic measuring system according to the embodiment when an adult with normal hearing is used as a test subject. FIG. 12B is a diagram showing the measurement results of the hearing characteristic measurement system of the comparative example when the test subject was an adult with normal hearing. FIG. 13 is a correlation diagram between the output time of the M-sequence sound as the stimulus sound and the measurement results of the auditory characteristics of the subject. FIG. 14 is an explanatory diagram of a tympanogram showing the measurement results of tympanometry. FIG. 15A is a diagram showing the measurement results of the comparative example auditory characteristic measurement system for a subject with normal hearing. FIG. 15B is a diagram showing the measurement results of the comparative example auditory characteristic measurement system on a subject with ossicular disruption. FIG. 15C is a diagram showing the measurement results of the comparative example auditory characteristic measuring system on a subject with ossicular fixation. FIG. 16 is an explanatory diagram of a mobility map. FIG. 17 is a diagram showing, in the form of an SPL curve, the measurement results of the auditory characteristic measuring system according to the embodiment, in the case where the subject was an adult with ossicular disruption. FIG. 18 is a diagram showing, in the form of a mobility map, the measurement results of the auditory characteristic measuring system according to the embodiment in the case where the subject is an adult who has suffered ossicular disruption. FIG. 19A is a diagram showing, as an SPL curve, the measurement results of the auditory characteristic measuring system according to the embodiment, when the subject was an adult with ossicular fixation. FIG. 19B is a diagram showing, as an SPL curve, the measurement results of the hearing characteristic measurement system of the comparative example when the subject was an adult with ossicular fixation. FIG. 20 is a diagram showing, in the form of an SPL curve, the measurement results of the comparative hearing characteristic measurement system when the subject was a newborn baby with hearing loss in both ears.

Embodiments of the present invention will be described in detail below with reference to the drawings. Note that each embodiment described below represents a specific example of the present invention. The numerical values, shapes, methods, components, component connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, in each figure, substantially identical components are designated by the same reference numerals, and duplicate explanations may be omitted or simplified.

[composition]
The auditory characteristic measurement system 100 (auditory characteristic measurement method) according to the embodiment is a system (method) for non-invasively measuring the auditory characteristic of a subject (i.e., a human) by outputting a stimulus sound Sd1 toward the ear canal 611 (see FIG. 3 ) in the ear 6 of the subject. As shown in FIG. 1 , the auditory characteristic measurement system 100 includes an output unit 11, a sound receiving unit 12, and an analysis unit 13. In other words, the auditory characteristic measurement method includes an output step S1, a sound receiving step S2, and an analysis step S3 (see FIG. 10 ). FIG. 1 is a schematic diagram showing the configuration of the auditory characteristic measurement system 100 according to the embodiment. FIG. 3 is a schematic diagram showing the structure of the human ear 6. FIG. 10 is a flowchart showing an example of the operation of the auditory characteristic measurement system 100 according to the embodiment.

The output unit 11 outputs a stimulus sound Sd1, which is random noise, toward the subject's ear canal 611. In other words, in the output step S1, the stimulus sound Sd1, which is random noise, is output toward the subject's ear canal 611. In this embodiment, the output unit 11 is composed of a computer device 1, an AD/DA converter 2, a measurement device 3, and an earphone 4 attached to a probe 31 attached to the measurement device 3.

As an example, computer device 1 is a laptop personal computer. Of course, computer device 1 is not limited to a laptop personal computer, and may also be a desktop personal computer, or an information terminal such as a smartphone or tablet terminal.

In the output unit 11, the computer device 1 executes a playback process for an audio file (e.g., a WAV file) containing the stimulation sound Sd1. As a result, the digital audio data of the stimulation sound Sd1 is converted to analog audio data by the AD/DA converter 2, and the converted analog audio data is transmitted to the measurement device 3. The measurement device 3 then outputs the stimulation sound Sd1 from the earphone 4 of the probe 31 based on the received analog audio data.

The stimulation sound Sd1 is output into the cavity 7 into which the tip of the probe 31 is inserted. This cavity 7 is a model that mimics the ear canal 611 of the subject, as described below. Here, the tip of the probe 31 is inserted into the cavity 7, but in reality, the tip of the probe 31 would be inserted into the ear canal 611 of the subject's ear 6.

As described above, the stimulus sound Sd1 is random noise. "Random noise" here refers to sound that includes the frequency band to be measured and whose sound pressure changes irregularly over time. In other words, the stimulus sound Sd1 is different from a frequency sweep sound, whose sound pressure changes periodically. "Frequency sweep sound" here refers to sound whose sound pressure changes periodically in a sinusoidal manner, and whose frequency changes continuously over time.

In this embodiment, the stimulus sound Sd1 is an M-sequence sound, as shown in Figure 2. Figure 2 is a schematic diagram illustrating an M-sequence sound. Here, an M-sequence is a pseudo-random number sequence consisting only of the two values "0" and "1" and having the longest period. In other words, while an M-sequence has periodicity, it also possesses the properties of random numbers within one period. In an M-sequence sound, "0" corresponds to the minimum value of the sound pressure of the stimulus sound Sd1 output by the output unit 11, and "1" corresponds to the maximum value of the sound pressure of the stimulus sound Sd1 output by the output unit 11. An M-sequence sound does not contain a single frequency component, but contains multiple frequency components. In other words, an M-sequence sound is pseudo-random noise whose frequency spectrum is constant across the frequency band being measured. Here, "constant" can mean completely constant or almost constant. In other words, an M-sequence sound is allowed to have a frequency spectrum that varies within a range of several percent from a reference value. In this way, an M-sequence sound has characteristics similar to white noise. Additionally, M-sequence sound is a sound that theoretically contains all frequency components up to half the sampling frequency.

In the embodiment, the frequency band of the M-sequence sound as the stimulation sound Sd1 is 0 to 48,000 Hz. That is, in the embodiment, the stimulation sound Sd1 includes frequency components in the range of 0 to 400 Hz. Also, in the embodiment, the stimulation sound Sd1 includes frequency components of 2 kHz or higher. Also, in the embodiment, the M-sequence sound as the stimulation sound Sd1 is adjusted so that the sound pressure level is output toward the subject's ear canal 611 (here, cavity 7) at a sound pressure level of approximately 60 dBSPL. Note that the numerical values of the frequency band and sound pressure level of the stimulation sound Sd1 are merely examples and are not limited to these numerical values.

The sound receiving unit 12 receives the reflected sound Sd2 generated when the stimulus sound Sd1 output by the output unit 11 is reflected in the ear canal 611. In other words, in the sound receiving step S2, the reflected sound Sd2 generated when the stimulus sound Sd1 output in the output step S1 is reflected in the ear canal 611 is received. In the embodiment, the sound receiving unit 12 is composed of a computer device 1, an AD/DA converter 2, a measuring device 3, and a microphone 5 provided on a probe 31 attached to the measuring device 3. In the sound receiving unit 12, the reflected sound Sd2 generated when the stimulus sound Sd1 output from the earphone 4 is reflected in the subject's ear canal 611 (here, the cavity 7) is received by the microphone 5. The measuring device 3 generates analog audio data of the reflected sound Sd2 from the reflected sound Sd2 received by the microphone 5. The generated analog audio data is sent to the AD/DA converter 2, where it is converted into digital audio data. The computer device 1 then receives the digital audio data sent from the AD/DA converter 2.

The analysis unit 13 performs frequency analysis on the reflected sound Sd2 received by the sound receiving unit 12. In other words, in analysis step S3, the reflected sound Sd2 received in sound receiving step S2 is frequency analyzed. In the embodiment, the analysis unit 13 is realized as a function of the computer device 1. The analysis unit 13 performs frequency analysis on the reflected sound Sd2 by performing FFT (Fast Fourier Transform) analysis on the digital audio data of the reflected sound Sd2 using MATLAB (registered trademark) on the computer device 1. In this way, the analysis unit 13 obtains an SPL (Sound Pressure Level) curve representing the auditory characteristics of the subject.

[Measurement principle]
First, the human auditory system will be described using Figure 3. As already mentioned, Figure 3 is a schematic diagram showing the structure of the human ear 6. As shown in Figure 3, the human ear 6 is broadly divided into an outer ear 61, a middle ear 62, and an inner ear 63. In the human ear 6, sound input into the ear canal 611 in the outer ear 61 vibrates the eardrum 612 located at the boundary between the outer ear 61 and the middle ear 62. The vibrations of the eardrum 612 are then transmitted to the inner ear 63 after passing through three ossicles 621 (malleus, incus, and stapes) in the middle ear 62. When the sound transmission function in the middle ear 62 does not function normally, a type of hearing loss known as conductive hearing loss is diagnosed.

Early detection and treatment of such middle ear 62 disorders, i.e., hearing disorders, is desirable, and early detection and treatment of hearing disorders, particularly in newborns, can greatly contribute to the future formation of knowledge and the development of language ability. Therefore, measuring the hearing characteristics of subjects, including newborns, can be useful for the early detection of hearing disorders such as those mentioned above.

The measurement principle of the auditory characteristics of a subject (i.e., a person) will be explained below using Figures 4A to 4C. Figure 4A is a schematic diagram showing the configuration of a calibration cavity 7, which will be described later. Figure 4B is a schematic diagram showing a cavity 7 simulating the subject's ear canal 611 in a state where the middle ear 62 is not resonating. Figure 4C is a schematic diagram showing a cavity 7 simulating the subject's ear canal 611 in a state where the middle ear 62 is resonating.

The cavity 7 shown in Figure 4A is an acoustic tube with one open end and the other closed end. When a stimulus sound Sd1 is output from one end of this cavity 7 toward the interior of the cavity 7, the sound pressure is expressed by the following equation (1).

In equation (1), "P" represents sound pressure, "V" represents the volume of air in cavity 7 when stimulation sound Sd1 is not being output (see Figures 4A to 4C), "ΔV" represents the change in the volume of air in cavity 7 due to the output of stimulation sound Sd1 (see Figures 4A to 4C), and "K" represents the bulk modulus of air. The same applies to equations (2) and (3) described below. In this way, sound pressure is proportional to the change in the volume of air in cavity 7.

Next, the cavities 7 shown in Figures 4B and 4C are both acoustic tubes open at both ends, and are models that mimic the subject's ear canal 611. It is assumed that the eardrum 612 is located at the other end of these cavities 7, and that the eardrum 612 vibrates when subjected to sound pressure. The cavity 7 shown in Figure 4B represents a state in which the frequency of the stimulus sound Sd1 has not reached the natural frequency f1 of the middle ear 62 (see Figure 5). The cavity 7 shown in Figure 4C represents a state in which the frequency of the stimulus sound Sd1 has reached the natural frequency f1 of the middle ear 62 and resonated, i.e., a state in which the phase of the vibration of the eardrum 612 has been reversed.

When a stimulation sound Sd1 is output from one end toward the inside of the cavity 7 shown in Figure 4B, the sound pressure of the reflected sound Sd2 is expressed by the following equation (2). Furthermore, when a stimulation sound Sd1 is output from one end toward the inside of the cavity 7 shown in Figure 4C, the sound pressure of the reflected sound Sd2 is expressed by the following equation (3). In equations (2) and (3), "ΔVTM" represents the change in volume of air pushed from the inside of the cavity 7 to the outside, or pushed from the outside of the cavity 7 to the inside (see Figures 4B and 4C). In other words, "ΔVTM" represents the change in volume of air caused by vibration of the eardrum 612.

In the cavity 7 shown in Figure 4B, the vibration of the eardrum 612 at the other end pushes air from the inside to the outside of the cavity 7, reducing the change in air volume within the cavity 7 and decreasing the sound pressure. On the other hand, in the cavity 7 shown in Figure 4C, the vibration of the eardrum 612 at the other end reverses phase, pushing air from the outside to the inside of the cavity 7, increasing the change in air volume within the cavity 7 and increasing the sound pressure.

Figure 5 shows an example of an adult's hearing characteristics measured by outputting a stimulus sound Sd1 toward the ear canal 611 of the adult's ear 6. Figure 5 illustrates an SPL curve representing the hearing characteristics of an adult. In Figure 5, the left vertical axis represents the sound pressure level of the reflected sound Sd2, the right vertical axis represents the change in air volume in the ear canal 611, and the horizontal axis represents the frequency of the stimulus sound Sd1 (reflected sound Sd2). As an example, the SPL curve is obtained by measuring the sound pressure of the reflected sound Sd2 in the ear canal 611 relative to the stimulus sound Sd1, converting the measured sound pressure to a sound pressure level, and plotting the result for each frequency of the stimulus sound Sd1. In Figure 5, the solid line represents the sound pressure level of the reflected sound Sd2, and the dashed line represents the change in air volume caused by vibration of the eardrum 612. This change in volume is calculated from the sound pressure level of the reflected sound Sd2 using the above-described principle of measuring hearing characteristics.

In Figure 5, the frequency at which the volume change is greatest is the natural frequency f1 of the middle ear 62. The sound pressure level of the reflected sound Sd2 changes from a minimum to a maximum value, with the natural frequency f1 of the middle ear 62 as the boundary. In other words, the median (i.e., the inflection point) of the frequency range where the sound pressure level of the reflected sound Sd2 changes from a minimum to a maximum value is approximately the natural frequency f1 of the middle ear 62. Also in Figure 5, the change ΔSPL in the sound pressure level of the reflected sound Sd2 from a minimum to a maximum value indicates the mobility of the eardrum 612. This is because the change ΔSPL in the sound pressure level of the reflected sound Sd2 and the change in air volume caused by the vibration of the eardrum 612 are proportional to each other. The natural frequency f1 of the middle ear 62 and the change ΔSPL in the sound pressure level of the reflected sound Sd2 are parameters that characterize human hearing characteristics.

Here, examples of measurement results of the hearing characteristics of a subject with normal hearing are shown in Figures 6A and 6B. Figure 6A is a diagram showing an SPL curve representing the hearing characteristics of an adult with normal hearing. Figure 6B is a diagram showing an SPL curve representing the hearing characteristics of a newborn baby with normal hearing. In each of Figures 6A and 6B, the vertical axis represents the sound pressure level of reflected sound Sd2, and the horizontal axis represents the frequency of stimulus sound Sd1 (reflected sound Sd2). As shown in Figure 6A, in an adult with normal hearing, the sound pressure level of reflected sound Sd2 changes from a minimum to a maximum value when the frequency of stimulus sound Sd1 is around 1 kHz. In other words, in an adult with normal hearing, the natural frequency f1 of the middle ear 62 is approximately 1 kHz.

On the other hand, as shown in Figure 6B, in a newborn with normal hearing, the sound pressure level of the reflected sound Sd2 changes from a minimum to a maximum when the frequency of the stimulus sound Sd1 is approximately 1 kHz, and also changes from a minimum to a maximum when the frequency of the stimulus sound Sd1 is approximately 260 Hz (see "f2" in the figure). The former change is similar to that in an adult with normal hearing and indicates that the natural frequency f1 of the middle ear 62 is approximately 1 kHz. On the other hand, the latter change indicates some kind of resonance occurring in the ear 6, a characteristic unique to newborns that is not observed in adults with normal hearing. As shown in Figure 7, this resonance is presumably caused by vibration of the soft tissue 613 covering the ear canal 611, rather than the eardrum 612. Figure 7 is an explanatory diagram illustrating the unique characteristics of the ear canal of a newborn. In Figure 7, the dashed line indicates vibration of the soft tissue 613. In other words, the soft tissue 613 that covers the ear canal 611 of a newborn baby is softer than the soft tissue 613 that covers the ear canal 611 of an adult, and it is presumed that the above-mentioned resonance occurs when this soft tissue 613 vibrates due to the stimulus sound Sd1.

By measuring the hearing characteristics of a subject based on the hearing characteristics of adults and newborns with normal hearing, it is believed possible to determine whether or not the subject has an abnormality in their hearing. For example, if the subject has a medical condition that causes the eardrum 612 to harden, the natural frequency f1 of the middle ear 62 will be higher than the reference value, or the eardrum 612 will have difficulty moving, causing the change in sound pressure level ΔSPL of the reflected sound Sd2 to be smaller than the reference value. Furthermore, for example, if the eardrum 612 has a hole or the ossicles 621 are broken, the natural frequency f1 of the middle ear 62 will be lower than the reference value, or the change in sound pressure level ΔSPL of the reflected sound Sd2 will be larger than the reference value. In this way, it is believed possible to determine whether or not the subject has an abnormality in their hearing based on the hearing characteristics of the subject, particularly the natural frequency f1 of the middle ear 62 and the change in sound pressure level ΔSPL of the reflected sound Sd2.

[Operation]
An example of the operation of the auditory characteristic measurement system 100 (auditory characteristic measurement method) according to the embodiment will be described below.

First, before measuring the auditory characteristics of the subject, calibration is performed using a cavity 7 that mimics the subject's ear canal 611. Specifically, the auditory characteristics measurement method according to the embodiment (steps S1 to S3, described below) is performed using this cavity 7 to obtain measured values of the SPL curve. The measured values of the SPL curve are then corrected so that they match the theoretical values of the SPL curve when this cavity 7 is used. In other words, a correction function is derived that matches the measured values of the SPL curve with the theoretical values of the SPL curve. Note that the difference between the measured values and the theoretical values of the SPL curve is thought to arise mainly from the frequency characteristics of the earphones 4. The correction function derived during calibration is applied to the measured values of the SPL curve obtained when the auditory characteristics measurement method according to the embodiment is performed on the subject's ear canal 611.

The cavity 7 used for calibration differs depending on whether the subject is an adult or a newborn. Specifically, the cavity 7 simulating the ear canal 611 of an adult is designed to have a length of 35 mm (i.e., the distance from the output surface of the stimulus sound Sd1 to the end surface of the wall at the other end inside the cavity 7) and a diameter of 8.5 mm. The cavity 7 simulating the ear canal 611 of a newborn is designed to have a length of 15 mm and a diameter of 4 mm. Furthermore, the cavity 7 simulating the ear canal 611 of a newborn is designed so that the wall (i.e., the soft tissue 613 covering the ear canal 611) is softer (i.e., the Young's modulus is smaller) than the cavity 7 simulating the ear canal 611 of an adult.

Here, a method for deriving the theoretical values of an SPL curve will be explained using Figure 8. Figure 8 is an explanatory diagram for explaining a method for deriving the theoretical values of an SPL curve. The cavity 7 shown in Figure 8 is an acoustic tube with one open end and the other closed end, similar to the cavity 7 shown in Figure 4A. The tip of a probe 31 is inserted into one end of this cavity 7. A stimulus sound Sd1 is output from the earphone 4 via the tip of the probe 31, and a reflected sound Sd2 is received by the microphone 5 via the tip of the probe 31. Note that in Figure 8, the probe 31, earphone 4, microphone 5, and cavity 7 are represented differently than in Figure 1.

For the cavity 7 shown in Figure 8, the theoretical value of the sound pressure of the reflected sound Sd2 is expressed by the following equation (4) based on the wave equation for a plane wave. The theoretical value of the sound pressure level of the reflected sound Sd2 is expressed by the following equation (5). In equations (4) and (5), "Ptheo" represents the theoretical value of the sound pressure of the reflected sound Sd2, "ΔV" represents the change in air volume in the cavity 7 due to the output of the stimulus sound Sd1, "ω" represents the angular frequency, "ρa" represents the air density, and "ua" represents the speed of sound. In equations (4) and (5), "γ" represents the wave number, "l" represents the length of the cavity 7 (see Figure 8), "S" represents the cross-sectional area of the cavity 7 (see Figure 8), "SPLtheo" represents the theoretical value of the sound pressure level of the reflected sound Sd2, and "Pref" represents the reference value of the sound pressure of the reflected sound Sd2. Here, the reference value is the minimum audible sound pressure for humans (20 μPa).

Figure 9 shows the theoretical values of the SPL curve for cavity 7 used for calibration. In Figure 9, the vertical axis represents the sound pressure level of reflected sound Sd2, and the horizontal axis represents the frequency of stimulus sound Sd1 (reflected sound Sd2). As shown in Figure 9, the sound pressure level of reflected sound Sd2 changes suddenly just before the frequency of stimulus sound Sd1 reaches 6000 Hz. This change represents resonance of cavity 7, and the resonant frequency is determined by the length of cavity 7.

As already mentioned, during calibration, the measured values of the SPL curve when using the above-mentioned cavity 7 are corrected so that they match the theoretical values of the SPL curve as shown in Figure 9. However, since there is a large discrepancy between the measured values of the SPL curve and the theoretical values near the resonant frequency of the cavity 7, correction is made here to the measured values of the SPL curve up to the resonant frequency of the cavity 7, but not to the measured values of the SPL curve above the resonant frequency of the cavity 7.

Next, a method for actually measuring the auditory characteristics of a subject will be described using Figure 10. As already mentioned, Figure 10 is a flowchart showing an example of the operation of the auditory characteristic measurement system 100 according to the embodiment. The method described below is performed after the above-mentioned calibration has been performed. First, the tip of the probe 31 is inserted into the ear canal 611 of the subject. In this state, the output unit 11 outputs the stimulation sound Sd1 toward the ear canal 611 of the subject (S1). Process S1 corresponds to output step S1. In this embodiment, the output unit 11 outputs the stimulation sound Sd1 for several seconds (here, 2 seconds).

After the output unit 11 outputs the stimulation sound Sd1, the sound receiving unit 12 receives the reflected sound Sd2 generated when the stimulation sound Sd1 output by the output unit 11 is reflected in the ear canal 611 (S2). Process S2 corresponds to the sound receiving step S2. Here, the output of the stimulation sound Sd1 by the output unit 11 and the reception of the reflected sound Sd2 by the sound receiving unit 12 are performed almost simultaneously.

Then, the analysis unit 13 performs frequency analysis on the reflected sound Sd2 received by the sound receiving unit 12 to obtain an SPL curve (S3). Process S3 corresponds to analysis step S3.

[advantage]
The advantages of the auditory characteristic measurement system 100 (auditory characteristic measurement method) according to the embodiment will be described below, along with a comparison with an auditory characteristic measurement system (auditory characteristic measurement method) of a comparative example. The auditory characteristic measurement method of the comparative example differs from the auditory characteristic measurement method according to the embodiment in that the stimulus sound Sd1 is a frequency sweep sound rather than an M-sequence sound. The auditory characteristic measurement method of the comparative example also differs from the auditory characteristic measurement method according to the embodiment in that, instead of obtaining an SPL curve by performing FFT in the analysis unit 13, the comparative example measures the sound pressure of the reflected sound Sd2, converts the measured sound pressure to a sound pressure level, and plots the SPL curve for each frequency of the stimulus sound Sd1.

Figure 11 is a comparison diagram of the measurement results obtained using the auditory characteristic measurement system 100 according to the embodiment and the measurement results obtained using an auditory characteristic measurement system according to a comparative example. In Figure 11, the vertical axis represents the sound pressure level of the reflected sound Sd2, and the horizontal axis represents the frequency of the stimulus sound Sd1 (reflected sound Sd2). Also in Figure 11, the solid line represents the measurement results obtained using the embodiment, the dashed-dotted line represents the measurement results obtained using the comparative example, and the dashed line represents the theoretical value of the SPL curve. Here, a cavity 7 simulating the external auditory canal 611 of a newborn baby is used as the measurement object. Also, here, the auditory characteristics are measured for stimulus sound Sd1 with a frequency range of 0 to 8000 Hz.

As shown in Figure 11, when the frequency of the stimulation sound Sd1 is in the range of 0 to 8000 Hz, the measurement results of the auditory characteristic measurement system 100 according to the embodiment and the comparative example are almost identical.

Next, the measurement results of the auditory characteristic measurement system 100 according to the embodiment and the comparative example auditory characteristic measurement system when the subject was an adult with normal hearing are compared. FIG. 12A shows the measurement results of the auditory characteristic measurement system 100 according to the embodiment when the subject was an adult with normal hearing. FIG. 12B shows the measurement results of the auditory characteristic measurement system according to the comparative example when the subject was an adult with normal hearing. In each of FIGS. 12A and 12B, the vertical axis represents the change ΔSPL in the sound pressure level of the reflected sound Sd2, and the horizontal axis represents the frequency of the stimulus sound Sd1 (reflected sound Sd2). In each of FIGS. 12A and 12B, each of the multiple thin solid lines represents a measurement result, and the thick solid line represents the average value of the multiple measurement results.

As shown in Figures 12A and 12B, when the frequency of the stimulation sound Sd1 is in the range of 0 to 2000 Hz, the measurement results of the auditory characteristic measurement system 100 according to the embodiment and the comparative example are almost identical. Specifically, the natural frequency f1 of the middle ear 62 is almost the same in both cases, and the change in sound pressure level ΔSPL of the reflected sound Sd2 is also almost the same.

In this way, the auditory characteristic measurement system 100 according to the embodiment can measure the auditory characteristics of a subject with accuracy equivalent to, or, as described below, equivalent to or greater than, that of the comparative auditory characteristic measurement system that uses a frequency sweep sound as the stimulus sound Sd1.

Furthermore, the auditory characteristic measurement system 100 according to the embodiment has the advantage of being able to shorten the time required to measure the auditory characteristics of a subject compared to the auditory characteristic measurement system of the comparative example. Specifically, with the auditory characteristic measurement system of the comparative example, when attempting to measure the auditory characteristics of a subject in a frequency band of 0 to several kHz, for example, the stimulus sound Sd1 must be output continuously for several tens of seconds. On the other hand, with the auditory characteristic measurement system 100 according to the embodiment, when attempting to measure the auditory characteristics of a subject in a frequency band of 0 to several kHz, for example, it is sufficient to continue outputting the stimulus sound Sd1 for only a few seconds.

If the subject moves, for example, by turning over in bed during measurement, noise caused by the subject's movement will be included in the measurement results, which could lead to a deterioration in the accuracy of the hearing characteristic measurement. Furthermore, the longer the measurement time, the higher the possibility that the subject will move during measurement, which makes the accuracy of the hearing characteristic measurement more likely to deteriorate. If the subject is an adult, they may be able to refrain from moving even if the measurement time is somewhat long, but if the subject is a child, they are likely to be unable to refrain and move as the measurement time becomes longer. In particular, if the subject is a newborn or infant, they do not have the concept of restraint in the first place, so naturally, they are very likely to move as the measurement time becomes longer.

In this regard, the auditory characteristic measurement system 100 according to the embodiment can significantly shorten the measurement time compared to the auditory characteristic measurement system of the comparative example. Therefore, with the auditory characteristic measurement system 100 according to the embodiment, the subject is less likely to move during measurement, and as a result, improved accuracy in measuring auditory characteristics can be expected.

In the comparative example auditory characteristic measurement system, it is possible to shorten the measurement time by increasing the frequency sweep speed of the stimulus sound Sd1. However, the faster the frequency sweep speed of the stimulus sound Sd1, the more the natural frequency f1 of the middle ear 62 being measured deviates, resulting in a deterioration in the accuracy of the auditory characteristic measurement. Therefore, as long as a frequency sweep sound is used as the stimulus sound Sd1, it is difficult to shorten the measurement time. Furthermore, the auditory characteristic measurement system 100 according to the embodiment uses random noise as the stimulus sound Sd1, and there is no need to sweep the frequency of the stimulus sound Sd1. This means that the natural frequency f1 of the middle ear 62 being measured is less likely to deviate, and as a result, improved accuracy in the auditory characteristic measurement can be expected.

Furthermore, the auditory characteristic measurement system 100 according to the embodiment uses an M-sequence sound as the stimulus sound Sd1, which tends to have a higher S/N ratio than a frequency sweep sound. Therefore, with the auditory characteristic measurement system 100 according to the embodiment, the noise components included in the auditory characteristic measurement results are smaller than the noise components included in the auditory characteristic measurement results obtained by the auditory characteristic measurement system of the comparative example, which has the advantage of resulting in higher accuracy in the auditory characteristic measurement.

[Specific examples]
Specific examples of advantages of using the auditory characteristic measurement system 100 (auditory characteristic measurement method) according to the embodiment will be described below, along with comparisons with a conventional auditory characteristic measurement method and a comparative auditory characteristic measurement system (auditory characteristic measurement method). The conventional auditory characteristic measurement method referred to here is tympanometry. Tympanometry is a measurement method in which a probe is inserted into a subject's ear canal 611, a sound of a predetermined frequency (e.g., 226 Hz) is output toward the ear canal 611, and acoustic admittance is measured while changing the pressure within the ear canal 611. FIG. 14 is an explanatory diagram of a tympanogram showing the results of tympanometry measurement. In FIG. 14, the vertical axis represents acoustic admittance, and the horizontal axis represents pressure within the ear canal 611.

In Figure 14, the solid line represents an example of a type A tympanogram. A type A tympanogram may appear when the subject's hearing is normal. Also in Figure 14, the dotted line represents an example of an Ad type tympanogram. An Ad type tympanogram may appear when the subject's ossicles 621 are disrupted, etc. Also in Figure 14, the dashed line represents an example of an As type tympanogram. An As type tympanogram may appear when the subject's ossicles 621 are fixed, etc.

However, measuring hearing characteristics using tympanometry may not be possible for some subjects, and in principle, it is not possible to measure hearing characteristics if the subject is a newborn. Conventionally, when hearing characteristics could not be measured using tympanometry, the condition of the middle ear 62 had to be examined using CT (Computed Tomography), and when the condition of the middle ear 62 could not be examined using CT either, it was necessary to actually perform surgery on the subject's ear to directly confirm the condition of the middle ear 62.

In contrast, the auditory characteristic measurement system 100 (auditory characteristic measurement method) according to the embodiment and the auditory characteristic measurement system (auditory characteristic measurement method) of the comparative example make it possible to check the condition of the middle ear 62 of subjects for whom it would be difficult to check the condition of the middle ear 62 using tympanometry, without the need for CT examination or ear surgery.

First, we will explain how to check the condition of the middle ear 62 using the comparative auditory characteristic measurement method. Figure 15A shows the measurement results of the comparative auditory characteristic measurement system on a subject with normal hearing. Figure 15B shows the measurement results of the comparative auditory characteristic measurement system on a subject with ossicles 621 disruption. Figure 15C shows the measurement results of the comparative auditory characteristic measurement system on a subject with ossicles 621 fixation.

15A to 15C are diagrams showing SPL curves in which the vertical axis represents the sound pressure level of reflected sound Sd2 and the horizontal axis represents the frequency of stimulus sound Sd1 (reflected sound Sd2). In FIG. 15A, the solid line represents the measurement results when the pressure in the ear canal 611 is 0 daPa, the dotted line represents the measurement results when the pressure in the ear canal 611 is -50 daPa, the dashed line represents the measurement results when the pressure in the ear canal 611 is 100 daPa, and the dashed line represents the measurement results when the pressure in the ear canal 611 is 200 daPa. In FIG. 15B, the solid line represents the measurement results when the pressure in the ear canal 611 is -40 daPa, the dotted line represents the measurement results when the pressure in the ear canal 611 is -100 daPa, and the dashed line represents the measurement results when the pressure in the ear canal 611 is -200 daPa. In addition, in Figure 15C, the solid line represents the measurement results when the pressure in the ear canal 611 is -20 [daPa], the dotted line represents the measurement results when the pressure in the ear canal 611 is -200 [daPa], and the dashed line represents the measurement results when the pressure in the ear canal 611 is 200 [daPa].

For example, as shown by the solid lines in Figures 15A to 15C, different SPL curves, in other words, hearing characteristics, are measured depending on the condition of the subject's middle ear 62 (here, the ossicles 621).

As already mentioned, the subject's hearing characteristics, particularly the natural frequency (resonance frequency) f1 of the middle ear 62 and the change in sound pressure level ΔSPL of the reflected sound Sd2, can serve as indicators of whether or not there is an abnormality in the subject's hearing, and more specifically, can serve as indicators of the mobility of the ossicles 621. Below, we will use Figure 16 to explain a mobility map that visually represents the mobility of the ossicles 621 based on the natural frequency (resonance frequency) f1 of the middle ear 62 and the change in sound pressure level ΔSPL of the reflected sound Sd2.

Figure 16 is an explanatory diagram of a mobility map. As shown in Figure 16, in the mobility map, the vertical axis represents the resonant frequency (i.e., the natural frequency of the middle ear 62), and the horizontal axis represents ΔSPL. Figure 16 also shows a mobility map for a large number of adult subjects. In Figure 16, the frame surrounded by a solid line represents the distribution of measurement results for multiple subjects with normal middle ears 62, the frame surrounded by a dashed line represents the distribution of measurement results for multiple subjects with disconnected ossicles 621, and the frame surrounded by a dotted line represents the distribution of measurement results for multiple subjects with fixed ossicles 621.

This mobility map can be used to confirm the condition of the subject's middle ear 62. For example, in Figure 16, the measurement results of the comparative auditory characteristic measurement system for a certain subject's right ear are indicated by an "o" and the measurement results of the comparative auditory characteristic measurement system for the left ear are indicated by an "x". Because this "o" is within the frame surrounded by a solid line, it is estimated that the middle ear 62 of the subject's right ear is normal. On the other hand, because this "x" is within the frame surrounded by a dashed line, it is estimated that there is an abnormality in the middle ear 62 of the subject's left ear; specifically, that the ossicles 621 have been detached.

As already mentioned, the auditory characteristic measurement system 100 (auditory characteristic measurement method) according to the embodiment is capable of measuring the auditory characteristics of a subject with accuracy equal to or greater than that of the auditory characteristic measurement system (auditory characteristic measurement method) of the comparative example. Therefore, the auditory characteristic measurement system 100 according to the embodiment can confirm the state of the subject's middle ear 62 with accuracy equal to or greater than that of the auditory characteristic measurement system of the comparative example.

Figure 17 is a diagram showing, as an SPL curve, the measurement results of the auditory characteristic measurement system 100 according to the embodiment when the subject was an adult with ossicular disruption 621. Figure 18 is a diagram showing, as a mobility map, the measurement results of the auditory characteristic measurement system 100 according to the embodiment when the subject was the same adult with ossicular disruption 621. The subject was a woman in her 50s who suffered from ossicular disruption due to ossicular malformation. In Figure 17, the vertical axis represents the change ΔSPL in sound pressure level of the reflected sound Sd2, and the horizontal axis represents the frequency of the stimulus sound Sd1 (reflected sound Sd2).

As shown in Figure 17, the auditory characteristic measurement system 100 according to the embodiment, like the auditory characteristic measurement system of the comparative example, is capable of measuring SPL curves as auditory characteristics for subjects whose hearing could not be measured by tympanometry. Furthermore, in Figure 18, the measurement results for the subject's left ear by the auditory characteristic measurement system 100 according to the embodiment are indicated by an "x." Because this "x" is within the dashed line frame, it can be seen that it has been estimated that the auditory ossicles 621 in the subject's left ear have been disrupted.

Figure 19A is a diagram showing, as an SPL curve, the measurement results of the auditory characteristic measurement system 100 according to the embodiment when the subject was an adult with fixation of the ossicles 621. Meanwhile, Figure 19B is a diagram showing, as an SPL curve, the measurement results of the auditory characteristic measurement system of a comparative example when the subject was the same adult with fixation of the ossicles 621. The subject was a woman in her 40s who suffered from otosclerosis. In both Figures 19A and 19B, the vertical axis represents the change ΔSPL in the sound pressure level of the reflected sound Sd2, and the horizontal axis represents the frequency of the stimulus sound Sd1 (reflected sound Sd2).

As shown in Figures 19A and 19B, the SPL curves measured by the auditory characteristic measurement system 100 according to the embodiment and the SPL curves measured by the auditory characteristic measurement system of the comparative example both show similar characteristics. In other words, the auditory characteristic measurement system 100 according to the embodiment, like the auditory characteristic measurement system of the comparative example, is capable of confirming the condition of the subject's middle ear 62. In other words, in the auditory characteristic measurement system 100 according to the embodiment (auditory characteristic measurement method), the results of the frequency analysis by the analysis unit 13 (analysis step S3) include an indicator that indicates the presence or absence of an abnormality in the ossicles 621 in the subject's middle ear 62.

On the other hand, the SPL curve measured by the comparative hearing characteristic measurement system shows occasional distortion due to the inclusion of noise components, whereas the SPL curve measured by the hearing characteristic measurement system 100 according to the embodiment contains almost no noise components. In other words, it is believed that the hearing characteristic measurement system 100 according to the embodiment can more accurately determine the condition of the subject's middle ear 62 than the comparative hearing characteristic measurement system.

The mobility maps shown in Figures 16 and 18 were created based on the measurement results of an auditory characteristic measurement system of a comparative example, and there is some overlap between the results of the subject with a normal middle ear 62 and the results of the subject with fixed ossicles 621, and there is also some overlap between the results of the subject with a normal middle ear 62 and the results of the subject with disconnected ossicles 621. If a mobility map is created based on the measurement results of the auditory characteristic measurement system 100 according to the embodiment, it is expected that these overlaps will be eliminated as the measurement accuracy of auditory characteristics improves.

Here, we will explain an example of measuring the hearing characteristics of a newborn baby using a comparative hearing characteristics measurement system (auditory characteristics measurement method). Figure 20 is a diagram showing the measurement results of the comparative hearing characteristics measurement system in the form of an SPL curve for a newborn baby with hearing loss in both ears. In Figure 20, the vertical axis represents the change ΔSPL in the sound pressure level of reflected sound Sd2, and the horizontal axis represents the frequency of stimulus sound Sd1 (reflected sound Sd2).

As shown in Figure 20, the comparative auditory characteristics measurement system is capable of measuring the SPL curve as the auditory characteristics of newborns, which in principle could not be measured using tympanometry. Note that the SPL curve shown in Figure 20 is equivalent to the SPL curve obtained by measuring a newborn with a normal middle ear 62, so it is thought that this newborn has some kind of abnormality somewhere in the external auditory canal 611 other than the middle ear 62.

As described above, the auditory characteristic measurement system 100 (auditory characteristic measurement method) according to the embodiment is capable of measuring an SPL curve similar to that of the auditory characteristic measurement system (auditory characteristic measurement method) of the comparative example. Therefore, even when measuring the auditory characteristics of a newborn baby as a subject using the auditory characteristic measurement system 100 according to the embodiment, it is believed that it will be possible to measure an SPL curve similar to that of the auditory characteristic measurement system of the comparative example. Furthermore, since the auditory characteristic measurement system 100 according to the embodiment can perform measurements in a shorter time than the auditory characteristic measurement system of the comparative example, it is expected that the measurement accuracy of the auditory characteristics of newborns will be improved compared to the auditory characteristic measurement system of the comparative example.

(Other embodiments)
Although the auditory characteristics measurement method, program, and auditory characteristics measurement system of the present invention have been described above based on the embodiments, the present invention is not limited to these embodiments. As long as they do not deviate from the gist of the present invention, various modifications that a person skilled in the art can conceive of to the present embodiments, and other forms constructed by combining some of the components of the embodiments, are also included within the scope of the present invention.

For example, in the embodiment, an M-sequence sound is used as the stimulation sound Sd1, but this is not limiting. For example, the stimulation sound Sd1 may be a sound based on a pseudo-random number sequence other than an M-sequence. Furthermore, the stimulation sound Sd1 may be noise such as white noise. In other words, the stimulation sound Sd1 needs only to include the frequency band to be measured and to exhibit irregular changes in sound pressure over time, or more specifically, to have a constant frequency spectrum across the frequency band to be measured.

When an impulse was used as the stimulation sound Sd1, good results were not obtained as measurements of the subject's hearing characteristics. This is thought to be because the stimulation sound Sd1 is applied to a living organism, and therefore the stimulation sound Sd1 is prone to attenuation. In other words, it is preferable that the stimulation sound Sd1 be a sound that is output to the subject's ear canal 611 for a certain, sufficient period of time.

Furthermore, in the embodiment, the output unit 11 and the sound receiving unit 12 are each composed of multiple devices, but this is not limited to this. For example, the output unit 11 and the sound receiving unit 12 may each be composed of a single device.

In addition, in the embodiment, the frequency band of the stimulation sound Sd1 is 0 to 48,000 Hz, which is on the order of several kHz, but it may also be on the order of several tens of kHz. Furthermore, the frequency band of the stimulation sound Sd1 may be changed as appropriate depending on the subject. For example, if the subject is an adult, the stimulation sound Sd1 may not include frequency components from 0 to several hundred Hz.

Furthermore, in the embodiment, the output unit 11 outputs the stimulation sound Sd1 for several seconds when measuring the auditory characteristics of the subject, but this is not limited to this. For example, the output time of the stimulation sound Sd1 may be several hundred milliseconds. Specifically, the output time of the stimulation sound Sd1 may be 200 milliseconds.

The results of the study on the output time of the stimulus sound Sd1 will be explained below using Figure 13. Figure 13 is a correlation diagram between the output time of the M-sequence sound as the stimulus sound Sd1 and the measurement results of the subject's hearing characteristics. The measurement results shown in Figure 13 represent measurement results using a cavity 7 (cavity 7 length: 35 mm, cavity 7 diameter: 8.5 mm) that simulates the ear canal 611 of an adult instead of the subject's ear canal 611. In Figure 13, the vertical axis represents the sound pressure level of the reflected sound Sd2, and the horizontal axis represents the frequency of the stimulus sound Sd1 (reflected sound Sd2). Also in Figure 13, the solid line represents the measurement results when the output time of the stimulus sound Sd1 is 300 milliseconds, the dashed line represents the measurement results when the output time of the stimulus sound Sd1 is 200 milliseconds, and the dashed line represents the measurement results when the output time of the stimulus sound Sd1 is 100 milliseconds.

As shown in Figure 13, the measurement results are almost the same when the output time of the stimulation sound Sd1 is 300 milliseconds and 200 milliseconds, and are also almost the same as the measurement results when the output time of the stimulation sound Sd1 is 2 seconds. On the other hand, when the output time of the stimulation sound Sd1 is 100 milliseconds, the sound pressure level of the reflected sound Sd2 is reduced by about 20 dB compared to when the output time is 200 milliseconds or 300 milliseconds, and the measurement results are also distorted. Therefore, it is considered preferable that the output time of the stimulation sound Sd1 be 200 milliseconds or longer.

Furthermore, for example, although in the embodiments the auditory characteristic measurement system 100 is realized by multiple devices, it may also be realized as a single device. For example, the auditory characteristic measurement system 100 may be realized as a single device equivalent to a server device. When the auditory characteristic measurement system 100 is realized by multiple devices, the components of the auditory characteristic measurement system 100 may be distributed in any manner among the multiple devices. For example, the components included in the computer device 1, etc. in the embodiments may be included in the server device. In other words, the present invention may be realized by cloud computing or edge computing.

Furthermore, in the embodiments, each component may be realized by executing a software program appropriate for that component. Each component may be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

Furthermore, each component may be realized by hardware. For example, each component may be a circuit (or integrated circuit). These circuits may form a single circuit as a whole, or each may be a separate circuit. Furthermore, each of these circuits may be a general-purpose circuit or a dedicated circuit.

In addition, the general or specific aspects of the present invention may be realized as a system, device, method, integrated circuit, computer program, or computer-readable recording medium such as a CD-ROM. They may also be realized as any combination of a system, device, method, integrated circuit, computer program, and recording medium.

For example, the present invention may be realized as a program for causing a computer (one or more processors) to execute an auditory characteristic measurement method, or as a computer-readable non-transitory recording medium on which such a program is recorded.

(summary)
As described above, the auditory characteristic measurement method according to the embodiment includes an output step S1, a sound receiving step S2, and an analysis step S3. In the output step S1, a stimulation sound Sd1, which is random noise, is output toward the ear canal 611 of the subject. In the sound receiving step S2, a reflected sound Sd2 generated when the stimulation sound Sd1 output in the output step S1 is reflected in the ear canal 611 is received. In the analysis step S3, the reflected sound Sd2 received in the sound receiving step S2 is subjected to frequency analysis.

This hearing characteristic measurement method has the advantage of shortening the time required to measure the subject's hearing characteristics compared to when a frequency sweep sound is used as the stimulus sound Sd1.

Also, for example, in the auditory characteristics measurement method, the stimulation sound Sd1 includes frequency components in the range of 0 to 400 Hz.

This method of measuring hearing characteristics has the advantage of making it easier to capture the unique characteristics of a newborn's hearing and measure the hearing characteristics of newborns.

Also, for example, in the auditory characteristics measurement method, the stimulation sound Sd1 includes frequency components of 2 kHz or higher.

This hearing characteristic measurement method is expected to enable measurement of a wider variety of hearing characteristics compared to when the stimulation sound Sd1 contains only frequency components below 2 kHz. In other words, it is experimentally known that the frequency characteristics of the stimulation sound Sd1 in the relatively high frequency band (e.g., frequency bands above 2 kHz) differ depending on the type of disease of the middle ear 62. Therefore, by including frequency components above 2 kHz in the stimulation sound Sd1, it is expected that the measurement results will be useful in determining the type of disease of the middle ear 62.

Also, for example, in the auditory characteristic measurement method, the stimulus sound Sd1 is an M-sequence sound.

This hearing characteristic measurement method has the advantage of shortening the time required to measure the subject's hearing characteristics compared to when a frequency sweep sound is used as the stimulus sound Sd1.

Furthermore, for example, in the hearing characteristic measurement method, the results of the frequency analysis in analysis step S3 include an indicator indicating the presence or absence of an abnormality in the ossicles 621 in the subject's middle ear 62.

This hearing characteristic measurement method has the advantage of being useful in detecting whether or not there is an abnormality in the ossicles 621.

Also, for example, the program causes one or more processors to execute the above-mentioned auditory characteristic measurement method.

This type of program has the advantage of shortening the time required to measure the subject's hearing characteristics compared to when a frequency sweep sound is used as the stimulus sound Sd1.

Furthermore, for example, the hearing characteristic measurement system 100 includes an output unit 11, a sound receiving unit 12, and an analysis unit 13. The output unit 11 outputs a stimulus sound Sd1, which is random noise, toward the subject's ear canal 611. The sound receiving unit 12 receives a reflected sound Sd2 that is generated when the stimulus sound Sd1 output by the output unit 11 is reflected in the ear canal 611. The analysis unit 13 performs frequency analysis on the reflected sound Sd2 received by the sound receiving unit 12.

This type of auditory characteristic measurement system 100 has the advantage of being able to shorten the time required to measure the auditory characteristics of the subject, compared to when a frequency sweep sound is used as the stimulus sound Sd1.

The present invention can be used as an auditory characteristics measurement method that outputs a stimulus sound Sd1 toward the subject's ear canal 611 to measure the auditory characteristics, for example, as a method for measuring the auditory characteristics of adults or children, including newborns.

100 Hearing characteristic measurement system 11 Output unit 12 Sound receiving unit 13 Analysis unit Sd1 Stimulus sound Sd2 Reflected sound 1 Computer device 2 AD/DA converter 3 Measurement device 31 Probe 4 Earphone 5 Microphone 6 Ear 61 Outer ear 611 Ear canal 612 Tympanic membrane 613 Soft tissue 62 Middle ear 621 Ossicles 63 Inner ear 7 Cavity f1 Natural frequency S1 Output step S2 Sound receiving step S3 Analysis step

Claims (7)

A method for operating an auditory characteristic measurement system including an output unit, a sound receiving unit, and an analysis unit, comprising:
an output step in which the output unit outputs a stimulus sound, which is random noise, to the ear canal of the subject;
a sound receiving step in which the sound receiving unit receives a reflected sound generated when the stimulation sound output in the output step is reflected in the ear canal;
an analyzing step in which the analyzing unit acquires an SPL (Sound Pressure Level) curve by frequency analyzing the reflected sound received in the sound receiving step, and extracts parameters characterizing the auditory characteristics of the subject from the SPL curve ,
A method for operating an auditory characteristics measurement system . The stimulation sound includes frequency components in the range of 0 to 400 Hz.
A method for operating the hearing characteristic measuring system according to claim 1. The stimulation sound includes a frequency component of 2 kHz or more.
A method for operating the hearing characteristic measuring system according to claim 1 or 2. The stimulus sound is an M-sequence sound.
A method for operating the hearing characteristic measuring system according to any one of claims 1 to 3. a result of the frequency analysis performed by the analyzing step including an index indicating the presence or absence of an abnormality in the ossicles in the middle ear of the subject;
A method for operating the hearing characteristic measuring system according to any one of claims 1 to 4. one or more processors,
Executing the method for operating the hearing characteristic measuring system according to any one of claims 1 to 5,
program. an output unit that outputs a stimulus sound, which is random noise, toward the ear canal of the subject;
a sound receiving unit that receives a reflected sound generated when the stimulating sound output by the output unit is reflected in the ear canal;
an analysis unit that acquires an SPL curve by frequency analyzing the reflected sound received by the sound receiving unit, and extracts parameters that characterize the auditory characteristics of the subject from the SPL curve ;
Hearing characteristics measurement system.