Operating method and program for auditory characteristics measurement system, and auditory characteristics measurement system

Abstract

To shorten a time required for measuring auditory characteristics of a subject.SOLUTION: An auditory characteristic measuring method includes an output step S1, a sound reception step S2, and an analysis step S3. In the output step S1, a stimulus sound, which is random noise, is output to the external auditory meatus of a subject. In the sound reception step S2, a reflection sound generated when the stimulus sound output in the output step S1 is reflected by the external auditory meatus is received. In the analysis step S3, the reflection sound received in the sound reception step S2 is subjected to frequency analysis.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to an auditory characteristic measurement method, a program, and an auditory characteristic measurement system, and more particularly to a technique for measuring auditory characteristics by outputting a stimulus sound toward the ear canal of a subject. [Background technology]

[0002] Patent Document 1 discloses an auditory threshold estimation device that estimates the hearing threshold used in an Auditory Brainstem Response (ABR) test for the definitive diagnosis of hearing impairment. This test is performed by providing a sound stimulus to the subject to excite the auditory nervous system, and acquiring and recording six to seven electrical potentials in the brainstem that occur within 10 milliseconds after the sound stimulus via lead electrodes placed on the scalp. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-188040 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide an auditory characteristic measurement method, a program, and an auditory characteristic measurement system that can shorten the time required to measure the auditory characteristic of a subject. [Means for solving the problem]

[0005] In order to achieve the above object, an auditory characteristic measurement method according to one aspect of the present invention includes an output step, a sound receiving step, and an analysis step. In the output step, a stimulus sound, which is random noise, is output toward the ear canal of a subject. In the sound receiving step, a reflected sound generated 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.

[0006] In order to achieve the above object, a program according to an embodiment of the present invention causes one or more processors to execute the above-described auditory characteristic measurement method.

[0007] In order to achieve the above object, an auditory characteristic measurement system according to one embodiment of the present invention includes 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 a 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 on the reflected sound received by the sound receiving unit. [Effects of the Invention]

[0008] The present invention provides an auditory characteristic measurement method, a program, and an auditory characteristic measurement system that can shorten the time required to measure the auditory characteristic of a subject. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an auditory characteristic measuring system according to an embodiment. [Figure 2] FIG. 2 is a schematic diagram showing an M-sequence tone. [Figure 3] FIG. 3 is a schematic diagram showing the structure of the human ear. [Figure 4A] FIG. 4A is a schematic diagram showing the configuration of a cavity for calibration. [Figure 4B]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. [Figure 4C] FIG. 4C is a schematic diagram showing a cavity simulating the ear canal of a subject, in which the middle ear is resonating. [Figure 5] FIG. 5 is a diagram showing an SPL (Sound Pressure Level) curve as an adult's hearing characteristic. [Figure 6A] FIG. 6A is a diagram showing an SPL curve as a hearing characteristic of an adult with normal hearing. [Figure 6B] FIG. 6B is a graph showing an SPL curve as the hearing characteristic of a newborn with normal hearing. [Figure 7] FIG. 7 is an explanatory diagram for explaining the unique characteristics of the external auditory canal of a newborn baby. [Figure 8] FIG. 8 is an explanatory diagram for explaining the theoretical values ​​of the SPL curve. [Figure 9] FIG. 9 is a diagram showing theoretical values ​​of the SPL curve in the cavity used for calibration. [Figure 10] FIG. 10 is a flowchart showing an example of the operation of the auditory characteristic measuring system according to the embodiment. [Figure 11] 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. [Figure 12A] 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. [Figure 12B] FIG. 12B is a diagram showing the measurement results of the hearing characteristic measuring system of the comparative example when the test subject was an adult with normal hearing. [Figure 13] 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. [Figure 14] FIG. 14 is an explanatory diagram of a tympanogram showing the measurement results of tympanometry. [Figure 15A]FIG. 15A is a diagram showing the measurement results of the auditory characteristic measuring system of the comparative example on a subject with normal hearing. [Figure 15B] FIG. 15B is a diagram showing the measurement results of the auditory characteristic measuring system of the comparative example on a subject who had ossicular disruption. [Figure 15C] FIG. 15C is a diagram showing the measurement results of the comparative example auditory characteristic measuring system on a subject with ossicular fixation. [Figure 16] FIG. 16 is an explanatory diagram of a mobility map. [Figure 17] 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, when the subject is an adult who has had ossicular disruption. [Figure 18] 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 had ossicular disruption. [Figure 19A] FIG. 19A is a diagram showing, as an SPL curve, the measurement results of the auditory characteristic measuring system according to the embodiment, in a case where the subject is an adult with ossicular fixation. [Figure 19B] FIG. 19B is a diagram showing, as an SPL curve, the measurement results of the hearing characteristic measuring system of the comparative example when the subject was an adult with ossicular fixation. [Figure 20] FIG. 20 is a diagram showing, in the form of an SPL curve, the measurement results of the comparative example hearing characteristic measurement system when the subject was a newborn baby with hearing loss in both ears. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that each of the embodiments described below represents a specific example of the present invention. Numerical values, shapes, methods, components, component connection forms, steps, step orders, etc. shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, in each drawing, substantially identical components are assigned the same reference numerals, and duplicated descriptions may be omitted or simplified.

[0011] [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 an 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.

[0012] The output unit 11 outputs the stimulation sound Sd1, which is random noise, toward the subject's ear canal 611. In other words, in the output step S1, the stimulation sound Sd1, which is random noise, is output toward the subject's ear canal 611. In this embodiment, the output unit 11 is made up of a computer device 1, an AD / DA converter 2, a measurement device 3, and an earphone 4 included in a probe 31 attached to the measurement device 3.

[0013] As an example, the computer device 1 is a laptop personal computer. Of course, the computer device 1 is not limited to a laptop personal computer, and may be a desktop personal computer or an information terminal such as a smartphone or a tablet terminal.

[0014] In the output unit 11, the computer device 1 executes a playback process of 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 into analog audio data by the AD / DA converter 2, and the converted analog audio data is transmitted to the measurement device 3. Then, the measurement device 3 outputs the stimulation sound Sd1 from the earphone 4 of the probe 31 based on the received analog audio data.

[0015] 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 imitates the ear canal 611 of the subject, as will be described later. 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 ear 6 of the subject.

[0016] As described above, the stimulus sound Sd1 is random noise. Here, "random noise" refers to a 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. Here, the "frequency sweep sound" is a sound whose sound pressure changes periodically in a sinusoidal waveform and whose frequency changes continuously over time.

[0017] In this embodiment, the stimulus sound Sd1 is an M-sequence sound, as shown in FIG. 2. FIG. 2 is a schematic diagram illustrating an M-sequence sound. Here, an M-sequence is a pseudo-random number sequence consisting of only two values, "0" and "1," and has the longest period. That is, an M-sequence has periodicity, but also has the properties of a random number 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 to be measured. Here, "constant" can include being completely constant as well as being 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. In addition, the M-sequence sound is a sound that theoretically includes all frequency components up to half the sampling frequency.

[0018] In the embodiment, the frequency band of the M-sequence sound as the stimulation sound Sd1 is 0 to 48000 Hz. That is, in the embodiment, the stimulation sound Sd1 includes frequency components in the range of 0 to 400 Hz. In addition, in the embodiment, the stimulation sound Sd1 includes frequency components of 2 kHz or higher. In addition, in the embodiment, the M-sequence sound as the stimulation sound Sd1 is adjusted so that the sound pressure level is output toward the ear canal 611 (here, the cavity 7) of the subject 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.

[0019] The sound receiving unit 12 receives a reflected sound Sd2 generated when the stimulus sound Sd1 output from 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 this embodiment, the sound receiving unit 12 is composed of a computer device 1, an AD / DA converter 2, a measurement device 3, and a microphone 5 included in a probe 31 attached to the measurement 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 ear canal 611 (here, the cavity 7) of the subject is received by the microphone 5. The measurement 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 transmitted from the AD / DA converter 2 .

[0020] 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 one 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) in the computer device 1. In this way, the analysis unit 13 obtains an SPL (Sound Pressure Level) curve as the auditory characteristics of the subject.

[0021] [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 work normally, a type of hearing loss known as conductive hearing loss is diagnosed.

[0022] 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 such hearing disorders.

[0023] The measurement principle of the auditory characteristics of a subject (i.e., a person) will be explained below with reference to Figures 4A to 4C. Figure 4A is a schematic diagram showing the configuration of a cavity 7 used for calibration, which will be described later. Figure 4B is a schematic diagram showing the cavity 7 simulating the ear canal 611 of the subject in a state where the middle ear 62 is not resonating. Figure 4C is a schematic diagram showing the cavity 7 simulating the ear canal 611 of the subject in a state where the middle ear 62 is resonating.

[0024] 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 the cavity 7 toward the inside of the cavity 7, the sound pressure is expressed by the following equation (1).

[0025]

number

[0026] In equation (1), "P" represents sound pressure, "V" represents the volume of air in the cavity 7 when the stimulation sound Sd1 is not being output (see FIGS. 4A to 4C), "ΔV" represents the amount of change in the volume of air in the cavity 7 due to the output of the stimulation sound Sd1 (see FIGS. 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 amount of change in the volume of air in the cavity 7.

[0027] Next, the cavities 7 shown in Figures 4B and 4C are both acoustic tubes with open ends, and are models that mimic the subject's ear canal 611. It is assumed that an eardrum 612 is located at the other end of each 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 does not reach 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 reaches the natural frequency f1 of the middle ear 62 and resonates, that is, a state in which the phase of the vibration of the eardrum 612 is reversed.

[0028] In the cavity 7 shown in FIG. 4B, when a stimulation sound Sd1 is output from one end toward the inside of the cavity 7, the sound pressure of the reflected sound Sd2 is expressed by the following equation (2). Also, in the cavity 7 shown in FIG. 4C, when a stimulation sound Sd1 is output from one end toward the inside of the cavity 7, the sound pressure of the reflected sound Sd2 is expressed by the following equation (3). In equations (2) and (3), "ΔVTM" represents the amount of change in the volume of air pushed from the inside to the outside of the cavity 7, or pushed from the outside to the inside of the cavity 7 (see FIGS. 4B and 4C). In other words, "ΔVTM" represents the amount of change in the volume of air caused by the vibration of the eardrum 612.

[0029]

number

[0030] In the cavity 7 shown in Fig. 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 amount of change in the volume of air within the cavity 7 and decreasing the sound pressure. On the other hand, in the cavity 7 shown in Fig. 4C, the phase of the vibration of the eardrum 612 at the other end is reversed, pushing air from the outside to the inside of the cavity 7, increasing the amount of change in the volume of air within the cavity 7 and increasing the sound pressure.

[0031] FIG. 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. FIG. 5 is a diagram illustrating an SPL curve representing the hearing characteristics of an adult. In FIG. 5, the vertical axis on the left represents the sound pressure level of the reflected sound Sd2, the vertical axis on the right represents the change in air volume in the ear canal 611, and the horizontal axis represents the frequency of the stimulus sound Sd1 (the reflected sound Sd2). For 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 FIG. 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.

[0032] In FIG. 5, the frequency at which the amount of change in volume is maximum is the natural frequency f1 of the middle ear 62. The sound pressure level of the reflected sound Sd2 changes from a minimum value 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 value to a maximum value is approximately the natural frequency f1 of the middle ear 62. Also in FIG. 5, the amount of change ΔSPL in the sound pressure level of the reflected sound Sd2 from a minimum value to a maximum value indicates the mobility of the eardrum 612. This is because the amount of change ΔSPL in the sound pressure level of the reflected sound Sd2 and the amount of change in the volume of air caused by the vibration of the eardrum 612 are proportional to each other. The natural frequency f1 of the middle ear 62 and the amount of change ΔSPL in the sound pressure level of the reflected sound Sd2 are parameters that characterize the human hearing characteristics.

[0033] 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 the reflected sound Sd2, and the horizontal axis represents the frequency of the stimulus sound Sd1 (reflected sound Sd2). As shown in Figure 6A, in an adult 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 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.

[0034] On the other hand, as shown in FIG. 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 same figure). The former change is similar to that of 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 FIG. 7, this resonance is presumably caused by vibration of the soft tissue 613 covering the ear canal 611, rather than the eardrum 612. FIG. 7 is an explanatory diagram illustrating the unique characteristics of the ear canal of a newborn. In FIG. 7, the dashed line indicates the vibration of the soft tissue 613. That is, it is presumed that the soft tissue 613 covering the ear canal 611 of a newborn baby is softer than the soft tissue 613 covering the ear canal 611 of an adult, and therefore the above-mentioned resonance occurs when this soft tissue 613 vibrates due to the stimulus sound Sd1.

[0035] 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 such as a hardened eardrum 612, the natural frequency f1 of the middle ear 62 may be higher than the reference value, or the eardrum 612 may become less mobile, resulting in a smaller change ΔSPL in the sound pressure level of the reflected sound Sd2 than the reference value. Furthermore, if the eardrum 612 has a hole or the ossicles 621 are broken, the natural frequency f1 of the middle ear 62 may be lower than the reference value, or the change ΔSPL in the sound pressure level of the reflected sound Sd2 may be larger than the reference value. Thus, 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 ΔSPL in the sound pressure level of the reflected sound Sd2.

[0036] [Operation] An example of the operation (auditory characteristic measurement method) of the auditory characteristic measurement system 100 according to the embodiment will be described below.

[0037] First, before measuring the auditory characteristics of the subject, calibration is performed using a cavity 7 that simulates 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 an SPL curve. The measured values ​​of the SPL curve are then corrected so that they coincide with the theoretical values ​​of the SPL curve when this cavity 7 is used. In other words, a correction function is derived that causes the measured values ​​of the SPL curve to coincide 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 due to the frequency characteristics of the earphones 4. The correction function derived by the 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.

[0038] Here, 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.

[0039] Here, a method for deriving the theoretical value of an SPL curve will be described with reference to FIG. 8. FIG. 8 is an explanatory diagram for explaining a method for deriving the theoretical value of an SPL curve. The cavity 7 shown in FIG. 8 is an acoustic tube with one end open and the other end closed, similar to the cavity 7 shown in FIG. 4A. The tip of a probe 31 is inserted into one end of the 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 the probe 31, earphone 4, microphone 5, and cavity 7 are represented differently in FIG. 8 than in FIG. 1.

[0040] In the cavity 7 shown in FIG. 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 the volume of the air 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 FIG. 8), "S" represents the cross-sectional area of ​​the cavity 7 (see FIG. 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).

[0041]

number

[0042] FIG. 9 is a diagram showing theoretical values ​​of the SPL curve for the cavity 7 used for calibration. In FIG. 9, 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). As shown in FIG. 9, the sound pressure level of the reflected sound Sd2 changes suddenly just before the frequency of the stimulus sound Sd1 reaches 6000 Hz. This change represents resonance of the cavity 7, and the resonant frequency is determined by the length of the cavity 7.

[0043] As already mentioned, in the calibration, the measured values ​​of the SPL curve when the above-mentioned cavity 7 is used are corrected so that they coincide with the theoretical values ​​of the SPL curve as shown in Fig. 9. However, since a large deviation occurs between the measured values ​​of the SPL curve and the theoretical values ​​near the resonant frequency of the cavity 7, here, correction is made 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 after the resonant frequency of the cavity 7.

[0044] Next, a method for actually measuring the auditory characteristics of a subject will be described with reference to FIG. 10. As already mentioned, FIG. 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 is 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 the output step S1. In the embodiment, the output unit 11 outputs the stimulation sound Sd1 for several seconds (here, 2 seconds).

[0045] After the output unit 11 outputs the stimulation sound Sd1, the sound receiving unit 12 receives a reflected sound Sd2 generated when the stimulation sound Sd1 output by the output unit 11 is reflected in the ear canal 611 (S2). The 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.

[0046] Thereafter, the analysis unit 13 obtains an SPL curve by performing frequency analysis on the reflected sound Sd2 received by the sound receiving unit 12 (S3). The process S3 corresponds to the analysis step S3.

[0047] [advantage] The advantages of the auditory characteristics measurement system 100 (auditory characteristics measurement method) according to the embodiment will be described below, along with a comparison with an auditory characteristics measurement system (auditory characteristics measurement method) of a comparative example. The auditory characteristics measurement method of the comparative example differs from the auditory characteristics measurement method according to the embodiment in that the stimulus sound Sd1 is a frequency swept sound rather than an M-sequence sound. The auditory characteristics measurement method of the comparative example also differs from the auditory characteristics 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 into a sound pressure level, and plots the SPL curve for each frequency of the stimulus sound Sd1.

[0048] Fig. 11 is a comparison diagram between the measurement results of the auditory characteristic measurement system 100 according to the embodiment and the measurement results of an auditory characteristic measurement system according to a comparative example. In Fig. 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). In Fig. 11, the solid line represents the measurement results of the embodiment, the dashed-dotted line represents the measurement results of 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 target. In addition, the auditory characteristic is measured for a frequency range of the stimulus sound Sd1 from 0 to 8000 Hz.

[0049] As shown in FIG. 11, within the frequency range of 0 to 8000 Hz of the stimulation sound Sd1, the measurement results of the auditory characteristic measuring system 100 according to the embodiment and the measurement results of the auditory characteristic measuring system of the comparative example are almost the same.

[0050] 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 will be compared. FIG. 12A is a diagram showing 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 is a diagram showing 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.

[0051] 12A and 12B, in the frequency range of 0 to 2000 Hz of the stimulation sound Sd1, the measurement results of the auditory characteristic measuring system 100 according to the embodiment and the comparative example are almost the same. Specifically, the natural frequency f1 of the middle ear 62 is almost the same in both cases, and the amount of change ΔSPL in the sound pressure level of the reflected sound Sd2 is also almost the same.

[0052] 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 equivalent to or greater than, that of the comparative example auditory characteristic measurement system that uses a frequency sweep sound as the stimulus sound Sd1, as will be described later.

[0053] Furthermore, the auditory characteristic measurement system 100 according to the embodiment has the advantage that the time required to measure the auditory characteristic of a subject can be shortened compared to the auditory characteristic measurement system of the comparative example. Specifically, in the auditory characteristic measurement system of the comparative example, when measuring the auditory characteristic 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, in the auditory characteristic measurement system 100 according to the embodiment, when measuring the auditory characteristic 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 several seconds.

[0054] Here, 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 may lead to a deterioration in the measurement accuracy of the hearing characteristics. Furthermore, the longer the measurement time, the higher the possibility that the subject will move during measurement, which makes the measurement accuracy of the hearing characteristics more likely to deteriorate. Here, 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 even have the concept of restraint in the first place, so naturally, they are very likely to move as the measurement time becomes longer.

[0055] 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 possibility that the subject will move during measurement is low, and as a result, improvement in the accuracy of auditory characteristic measurement can be expected.

[0056] In the comparative example, 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 measurement accuracy of the auditory characteristics. 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 characteristics 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 makes it less likely that the natural frequency f1 of the middle ear 62 being measured will deviate, and as a result, it is expected that the measurement accuracy of the auditory characteristics will be improved.

[0057] Furthermore, the auditory characteristic measurement system 100 according to the embodiment employs an M-sequence sound as the stimulus sound Sd1, which tends to have a higher S / N ratio than a frequency sweep sound. Therefore, the auditory characteristic measurement system 100 according to the embodiment has an advantage that 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, resulting in high accuracy in measuring the auditory characteristic.

[0058] [Specific example] 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 an auditory characteristic measurement system (auditory characteristic measurement method) of a comparative example. The conventional auditory characteristic measurement method referred to here is tympanometry. Tympanometry is a measurement method in which a probe is inserted into the ear canal 611 of a subject, 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 in the ear canal 611. FIG. 14 is an explanatory diagram of a tympanogram showing the measurement results of tympanometry. In FIG. 14, the vertical axis represents acoustic admittance, and the horizontal axis represents the pressure in the ear canal 611.

[0059] In FIG. 14, the solid line represents an example of a type A tympanogram. A type A tympanogram may appear when the subject has normal hearing. Also in FIG. 14, the dotted line represents an example of a type Ad tympanogram. An type Ad tympanogram may appear when the subject's ossicles 621 are severed or the like. Also in FIG. 14, the dashed line represents an example of a type As tympanogram. An type As tympanogram may appear when the subject's ossicles 621 are fixed or the like.

[0060] Here, there is a problem that measurement of hearing characteristics by tympanometry may not be possible for some subjects, and in fact, it is not possible to measure the hearing characteristics of newborns in principle. Conventionally, when measurement of hearing characteristics by tympanometry is not possible, the state of the middle ear 62 has been examined by CT (Computed Tomography), and when the state of the middle ear 62 cannot be examined by CT either, it has been necessary to actually perform surgery on the subject's ear to directly confirm the state of the middle ear 62.

[0061] 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 state of the middle ear 62 of subjects for whom it would be difficult to check the state of the middle ear 62 using tympanometry, without the need for CT examination or ear surgery.

[0062] First, a method for checking the condition of the middle ear 62 using an auditory characteristic measurement method of a comparative example will be described. Fig. 15A shows the measurement results of the auditory characteristic measurement system of the comparative example on a subject with normal hearing. Fig. 15B shows the measurement results of the auditory characteristic measurement system of the comparative example on a subject with ossicles 621 disruption. Fig. 15C shows the measurement results of the auditory characteristic measurement system of the comparative example on a subject with ossicles 621 fixation.

[0063] 15A to 15C are diagrams showing SPL curves in which the vertical axis represents the sound pressure level of the reflected sound Sd2 and the horizontal axis represents the frequency of the stimulation 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-dotted 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]. Also, 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].

[0064] For example, as shown by the solid lines in each of FIGS. 15A to 15C, it can be seen that different SPL curves, in other words, hearing characteristics are measured depending on the state of the subject's middle ear 62 (here, ossicles 621).

[0065] As already mentioned, among the auditory characteristics of the subject, the natural frequency (resonant frequency) f1 of the middle ear 62 and the change ΔSPL in the sound pressure level of the reflected sound Sd2 can serve as indicators of whether or not there is an abnormality in the auditory sense of the subject, and more specifically, as indicators of the mobility of the ossicles 621. Below, a mobility map that visually represents the mobility of the ossicles 621 based on the natural frequency (resonant frequency) f1 of the middle ear 62 and the change ΔSPL in the sound pressure level of the reflected sound Sd2 will be described with reference to FIG.

[0066] Fig. 16 is an explanatory diagram of a mobility map. As shown in Fig. 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. Fig. 16 also shows a mobility map of a large number of adult subjects. In Fig. 16, the frame surrounded by a solid line represents the distribution of the measurement results of multiple subjects with normal middle ears 62, the frame surrounded by a dashed line represents the distribution of the measurement results of multiple subjects with detached ossicles 621, and the frame surrounded by a dotted line represents the distribution of the measurement results of multiple subjects with fixed ossicles 621.

[0067] By using this mobility map, it is possible to confirm the condition of the subject's middle ear 62. For example, in Fig. 16, the measurement results of the comparative auditory characteristic measurement system for the right ear of a certain subject are indicated by "◯", and the measurement results of the comparative auditory characteristic measurement system for the left ear are indicated by "X". Because this "◯" 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 are detached.

[0068] As already described, the auditory characteristic measurement system 100 (auditory characteristic measurement method) according to the embodiment can measure the auditory characteristic of a subject with accuracy equal to or higher 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 higher than that of the auditory characteristic measurement system of the comparative example.

[0069] Fig. 17 is a diagram showing, as an SPL curve, the measurement results of the auditory characteristic measuring system 100 according to the embodiment when the subject was an adult with ossicles 621 disrupted. Fig. 18 is a diagram showing, as a mobility map, the measurement results of the auditory characteristic measuring system 100 according to the embodiment when the subject was the same adult with ossicles 621 disrupted. The subject was a woman in her 50s who suffered from ossicles disruption due to ossicular malformation. In Fig. 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).

[0070] As shown in Fig. 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 an SPL curve as the auditory characteristic of a subject whose hearing could not be measured by tympanometry. Also, in Fig. 18, the measurement result of the auditory characteristic measurement system 100 according to the embodiment for the left ear of this subject is indicated by an "x", and since this "x" is within the frame surrounded by the dashed line, it can be seen that it has been estimated that the ossicles 621 in the left ear of this subject have been severed.

[0071] 19A is a diagram showing, as an SPL curve, the measurement results of the auditory characteristic measuring system 100 according to the embodiment when the subject was an adult with fixation of the ossicles 621. Meanwhile, FIG. 19B is a diagram showing, as an SPL curve, the measurement results of the auditory characteristic measuring system of the 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 FIG. 19A and FIG. 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).

[0072] 19A and 19B, the SPL curves measured by the auditory characteristic measurement system 100 according to the embodiment and the auditory characteristic measurement system of the comparative example both show similar characteristics. That is, the auditory characteristic measurement system 100 according to the embodiment, like the auditory characteristic measurement system of the comparative example, is capable of checking the state 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 result of the frequency analysis by the analysis unit 13 (analysis step S3) includes an index indicating the presence or absence of an abnormality in the ossicles 621 in the subject's middle ear 62.

[0073] On the other hand, the SPL curve measured by the hearing characteristic measurement system of the comparative example 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 confirm the state of the subject's middle ear 62 than the hearing characteristic measurement system of the comparative example.

[0074] 16 and 18 are created based on the measurement results of the auditory characteristic measurement system of the comparative example, and the results of the subject with a normal middle ear 62 partially overlap with the results of the subject with fixed ossicles 621, and the results of the subject with a normal middle ear 62 partially overlap with the results of the subject with detached ossicles 621. If the 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 resolved as the measurement accuracy of the auditory characteristic improves.

[0075] Here, an example of measuring the auditory characteristics of a newborn baby as a test subject using an auditory characteristics measurement system (auditory characteristics measurement method) of a comparative example will be described. Fig. 20 is a diagram showing the measurement results of the auditory characteristics measurement system of the comparative example in the case where the test subject was a newborn baby with hearing loss in both ears, as an SPL curve. In Fig. 20, the vertical axis represents the amount of 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).

[0076] As shown in Fig. 20, the hearing characteristic measurement system of the comparative example is capable of measuring the SPL curve as the hearing characteristic of a newborn baby, which in principle could not be measured by tympanometry. Note that the SPL curve shown in Fig. 20 is equivalent to the SPL curve obtained by measuring a newborn baby with a normal middle ear 62, so it is thought that this newborn baby has some kind of abnormality in a part of the external auditory canal 611 other than the middle ear 62.

[0077] As described above, the auditory characteristic measurement system 100 (auditory characteristic measurement method) according to the embodiment can measure an SPL curve similar to that of the auditory characteristic measurement system (auditory characteristic measurement method) of the comparative example. Therefore, even when the auditory characteristic measurement system 100 according to the embodiment is used to measure the auditory characteristics of a newborn as a test subject, it is thought that it is possible to measure an SPL curve similar to that of the auditory characteristic measurement system of the comparative example. Furthermore, the auditory characteristic measurement system 100 according to the embodiment can perform measurement in a shorter time than the auditory characteristic measurement system of the comparative example, and therefore is expected to provide improved measurement accuracy for the auditory characteristics of newborns compared to the auditory characteristic measurement system of the comparative example.

[0078] (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.

[0079] 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 may be any sound that includes the frequency band to be measured and whose sound pressure changes irregularly over time, or more specifically, whose frequency spectrum is constant across the frequency band to be measured.

[0080] When an impulse was used as the stimulus sound Sd1, good results were not obtained as measurements of the subject's hearing characteristics. This is thought to be because the stimulus sound Sd1 is applied to a living body, and the stimulus sound Sd1 is easily attenuated. In other words, it is preferable that the stimulus sound Sd1 be a sound that is output to the subject's ear canal 611 for a certain sufficient period of time.

[0081] In the embodiment, the output unit 11 and the sound receiving unit 12 are each configured by a plurality of devices, but this is not limiting. For example, the output unit 11 and the sound receiving unit 12 may each be configured by a single device.

[0082] 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 be on the order of several tens of kHz. The frequency band of the stimulation sound Sd1 may be changed appropriately 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 hundreds of Hz.

[0083] 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.

[0084] The following describes the results of the study on the output time of the stimulus sound Sd1 with reference to FIG. 13. FIG. 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 auditory characteristics of the subject. The measurement results shown in FIG. 13 represent the results of measurement using a cavity 7 (length of the cavity 7: 35 mm, diameter of the cavity 7: 8.5 mm) simulating the ear canal 611 of an adult instead of the ear canal 611 of the subject. In FIG. 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 FIG. 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 dash-dotted line represents the measurement results when the output time of the stimulus sound Sd1 is 100 milliseconds.

[0085] As shown in Fig. 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.

[0086] Furthermore, for example, although the auditory characteristic measurement system 100 in the embodiments is realized by multiple devices, it may also be realized as a single device. For example, the auditory characteristic measurement system 100 may also be realized as a single device corresponding 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 of the computer device 1, etc. in the embodiments may also be provided in a server device. In other words, the present invention may be realized by cloud computing or edge computing.

[0087] In the embodiments, each component may be realized by executing a software program suitable for that component, or 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.

[0088] 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.

[0089] Furthermore, the general or specific aspects of the present invention may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0090] 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 may be realized as a computer-readable non-transitory recording medium on which such a program is recorded.

[0091] (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 stimulus 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 stimulus 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.

[0092] Such an auditory characteristic measurement method has the advantage that the time required to measure the auditory characteristic of the subject can be shortened compared to when a frequency sweep sound is used as the stimulus sound Sd1.

[0093] Furthermore, for example, in the auditory characteristic measurement method, the stimulation sound Sd1 includes frequency components in the range of 0 to 400 Hz.

[0094] Such a hearing characteristic measurement method has the advantage that it becomes easier to capture the characteristics specific to the hearing of a newborn baby, and it becomes easier to measure the hearing characteristics of a newborn baby.

[0095] Furthermore, for example, in the auditory characteristic measurement method, the stimulation sound Sd1 includes frequency components of 2 kHz or more.

[0096] This auditory characteristic measurement method is expected to enable measurement of a wider variety of auditory characteristics than when the stimulation sound Sd1 contains only frequency components below 2 kHz. That is, it is experimentally known that the frequency characteristics of the stimulation sound Sd1 in a relatively high frequency band (e.g., a frequency band of 2 kHz or higher) differ depending on the type of disease of the middle ear 62. Therefore, by including frequency components of 2 kHz or higher 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.

[0097] Also, for example, in the auditory characteristic measurement method, the stimulus sound Sd1 is an M-sequence sound.

[0098] Such an auditory characteristic measurement method has the advantage that the time required to measure the auditory characteristic of the subject can be shortened compared to when a frequency sweep sound is used as the stimulus sound Sd1.

[0099] Furthermore, for example, in the hearing characteristic measurement method, the result of the frequency analysis in the analysis step S3 includes an index indicating the presence or absence of an abnormality in the ossicles 621 in the middle ear 62 of the subject.

[0100] Such an auditory characteristic measuring method has the advantage that it can be used to detect whether or not there is an abnormality in the ossicles 621.

[0101] Also, for example, the program causes one or more processors to execute the above-described auditory characteristic measurement method.

[0102] Such a program has the advantage that the time required to measure the auditory characteristics of the subject can be shortened compared to when a frequency sweep sound is used as the stimulus sound Sd1.

[0103] Moreover, 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 ear canal 611 of the subject. The sound receiving unit 12 receives a reflected sound Sd2 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.

[0104] The hearing characteristic measurement system 100 has an advantage that the time required to measure the hearing characteristic of the subject can be shortened compared to when a frequency sweep sound is used as the stimulus sound Sd1. [Industrial Applicability]

[0105] The present invention can be used as an auditory characteristics measurement method for measuring auditory characteristics by outputting a stimulus sound Sd1 toward the ear canal 611 of a subject, for example, as a method for measuring the auditory characteristics of adults or children including newborns. [Explanation of symbols]

[0106] 100 Hearing Characteristics Measurement System 11 Output section 12 Sound receiver 13 Analysis Department Sd1 Stimulus sound Sd2 Reflected sound 1. Computer equipment 2 AD / DA converters 3. Measuring equipment 31 Probe 4. Earphones 5 microphones 6 Ears 61 External ear 611 External auditory canal 612 Eardrum 613 Soft tissue 62 Middle ear 621 Ossicles 63 Inner ear 7 Cavity f1 natural frequency S1 Output Step S2 Receiving Step S3 Analysis Step

Claims

1. 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.

2. 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.

3. 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.

4. 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.

5. 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.

6. one or more processors, Executing the method for operating the hearing characteristic measuring system according to any one of claims 1 to 5, program.

7. 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.

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