JP5603281B2 - Hearing examination apparatus, method and computer program, hearing aid adjustment system - Google Patents

Description

  The present invention relates to an auditory test which realizes objective measurement of an uncomfortable threshold and a comfortable value by an objective test method in measurement of an unpleasant threshold (UCL) and a comfortable value (MCL) with respect to a loudness among auditory functions. The present invention relates to an apparatus, an auditory function measuring method, and a computer program for executing the auditory function measuring method.

  The most common hearing function test is the hearing test. By hearing test, measure the volume of the smallest sound that can be heard in the auditory function. The volume of the smallest sound that can be heard is called the minimum audible threshold level (Healing Threshold Level). Hereinafter, a specific hearing test method will be described.

  The examiner presents a pure tone having a specific frequency as a test sound to one ear of the subject. Then, the volume of the pure tone to be presented is gradually increased. When the test subject hears the test sound, he or she responds by pressing a button or raising his hand. The test performed by the subject answering whether or not the test sound is heard is called a subjective test. Such an answer is hereinafter referred to as a conscious answer.

  A subjective test requires the ability of the subject to recognize and respond to his / her awareness. Therefore, infants and the like cannot make a conscious answer. Therefore, an objective test is performed on subjects who cannot make a conscious answer. The objective test does not require the subject's listening awareness and conscious answer, but uses a biological reaction induced by the subject's listening to the sound.

  In these biological reactions, there is an electroencephalogram called “evoked potential” that is evoked when a subject listens to sound. Using this evoked potential, there is a method for measuring the auditory brainstem response (ABR) of Patent Document 1 or the auditory steady-state response (ASSR) of Patent Document 2. The auditory brainstem response or auditory steady state response is measured by whether or not an evoked potential is observed. The minimum sound pressure at which the evoked potential is recognized is specified by decreasing the sound sequentially from a loud sound in which the evoked potential is easy to distinguish. Thereby, the minimum audible value (HTL) can be measured by measuring the auditory brainstem response or the auditory steady state response.

  On the other hand, in the examination of the auditory function, measurement is performed for hearing above the threshold (superthreshold).

  When adjusting the hearing aid, it is important to measure the discomfort threshold. Discomfort threshold is a result of measuring how loud a subject using a hearing aid can hear, and how loud it feels that it is too loud to feel uncomfortable and unbearable It is.

  In the measurement, like a hearing test, a specific pure tone is presented as a test sound to one ear of the subject, and the sound is gradually increased. The hearing test starts with a sound that is so low that it cannot be heard by the subject, but the uncomfortable threshold starts with a sound pressure that the subject can hear and does not oversound. If it is too loud and uncomfortable, or if you feel that the sound is too loud to be heard for a long time, it will be measured by reporting or giving a signal such as pressing a button.

  As for the objective test method for hearing above the threshold, the measurement of supplementary phenomenon with ABR as shown in Non-Patent Document 1 and the measurement of supplementary phenomenon with ASSR as in Non-Patent Document 2 are attempted. It has been. However, no method for measuring the discomfort threshold is shown.

Special table 2010-504139 International Publication No. 2008/038650

Yu Aoyagi, “Auditory evoked potentials” Eaubrilium Research 69, 3, 113-126, 2010 Terence W. P. Et al., “Human Auditory-state responses”, International Journal of Audio, Vol. 42, No. 4, 177-219, 2003. "Chapter 23 Slow Response to the Top", Sotaro Funasaka, edited by Shinjiro Onishi, supervised by Atsuro Suzuki (1985) "Auditory Brainstem Reaction-Its Fundamentals and Clinical Practices", Medical View pp. 381-392

  As described above, there is an objective measurement method for hearing ability, but there is no objective measurement method for the discomfort threshold. Therefore, the discomfort threshold is measured only by a subjective measurement method. However, the definition of the unpleasant threshold that the sound is too loud and unpleasant, or cannot be heard for a long time varies depending on the subject. It can be said that the definition of the discomfort threshold is ambiguous for the subject.

  More specifically, the response to the sense of loudness varies depending on the difference in interpretation and character of the language by the subject, and the perceptual and physiological meaning of the measured discomfort threshold varies depending on the subject. For example, if the subject is patient, the discomfort threshold value is relatively large because the subject can be patient with a louder sound. If it is a subject who judges that the sound that is felt as annoying even a little is uncomfortable, the unpleasant threshold value becomes a relatively small value. In this way, if the discomfort threshold varies depending on the judgment criteria, when adjusting the hearing aid of the subject who has obtained a larger value as the discomfort threshold, it tends to give a larger amplification factor, and the sound passed through the hearing aid Becomes noisy. On the other hand, when a hearing aid is adjusted to a subject who has obtained a smaller value as a discomfort threshold, a smaller amplification factor tends to be given, and the sound passing through the hearing aid is not sufficiently amplified and is difficult to hear.

  In addition, subjective measurement of the discomfort threshold requires the subject to be too loud, as the subject reports or signals that he / she is aware that the sound is too loud and uncomfortable, or too loud to hear for a long time. I need to listen to the sound. For this reason, the measurement itself is uncomfortable and listening to too loud sounds can be dangerous for the auditory organ. As described above, since the subjective measurement of the unpleasant threshold is a heavy burden on the subject, there is a tendency to avoid the measurement at the hearing aid adjustment site in spite of the importance in adjusting the amplification factor.

  As described above, measuring the discomfort threshold by the subjective measurement method that measures the subject's subjectivity with respect to the volume of sound is not suitable as a measurement for adjusting the amplification factor of the hearing aid. Furthermore, the subjective evaluation of the loudness varies greatly depending on the surrounding sound environment and the sound to be heard. In everyday life, hearing aids are used in a variety of sound environments, from relatively quiet rooms to watching TV, conferences, and crowds and crowds of stations. It is important not to adjust the amplification factor based on subjective values that vary greatly depending on the situation, but to determine the amplification factor based on physiological limits. In particular, the upper limit of amplification is important in order to protect the hearing aid user so as not to cause loss of the residual hearing due to the exposure of loud sounds while making the best use of the hearing ability of the hearing aid user. Nevertheless, until now, the development of an objective measurement method for discomfort threshold has not been promoted.

  In the objective measurement method using the evoked potential to measure the minimum audible value, in order to measure a very small potential, the test sound of the same condition is repeated many times, and the time pattern of the potential obtained each time is used as the test sound. A method of performing an averaging process based on the presentation timing is taken. Presenting repeated loud sounds to measure the unpleasant threshold has not been done because of the risk of deafness.

  This invention is made | formed in view of the said subject, The objective is to estimate a test subject's discomfort threshold, suppressing the burden concerning a test subject.

  An auditory inspection apparatus according to an embodiment of the present invention includes a test sound range setting unit that sets a plurality of types of test sounds determined by a combination of at least three different sound pressures and at least two types of frequencies, and the same frequency or the same. A presentation order determining unit that determines a presentation order of the plurality of types of inspection sounds so that sound pressure inspection sounds are not continuously presented, and an inspection sound that outputs the plurality of types of inspection sounds in the determined presentation order An evoked potential induced by each test sound having the same frequency f and different sound pressures a, b, and c (a <b <c), and an output unit, an electroencephalogram measurement unit that measures the subject's electroencephalogram Is extracted from the measured electroencephalogram, the latency or amplitude of the evoked potential A corresponding to the test sound of the sound pressure a, the latency or amplitude of the evoked potential B corresponding to the test sound of the sound pressure b, and the sound pressure c. Corresponding to the inspection sound A calculation unit for calculating the latency or amplitude C of the power generation position C; a first difference between the latency or amplitude of the evoked potential A and the latency or amplitude of the evoked potential B; and the latency of the evoked potential B The second difference between the time or amplitude and the latency or amplitude of the evoked potential C is calculated, and when the amount of change of the second difference with respect to the first difference is equal to or greater than a predetermined value, a predetermined value is determined. And an estimation unit for estimating a discomfort threshold at the frequency f based on the relationship between the change amount and the sound pressure.

  The calculation unit may include an N1 determination unit that extracts a negative component N1 that appears about 100 milliseconds after the time when each test sound is presented as an evoked potential induced by each test sound. .

  The calculation unit may include a latency calculation unit that calculates the latency of each negative component N1 of the evoked potential A, the evoked potential B, and the evoked potential C.

  When the amount of change of the second difference with respect to the first difference is smaller than a predetermined value, the inspection sound range setting unit relates to the inspection sound of the frequency f and is at least two types higher than the sound pressure c Sound pressures d and e (c <d <e) are further set, and the presentation order determination unit further determines the order of presentation of a plurality of types of inspection sounds including the set inspection sounds, and outputs the inspection sound The unit outputs the plurality of types of inspection sounds in the determined presentation order, and the calculation unit checks the latency or amplitude of the evoked potential D corresponding to the inspection sound of the sound pressure d and the sound pressure e. Calculating the latency or amplitude of the evoked potential E corresponding to the sound, and the estimating unit calculates a third difference between the latency or amplitude of the evoked potential C and the latency or amplitude of the evoked potential D, and The latency or amplitude of the evoked potential D and the latency or amplitude of the evoked potential E When the change amount of the fourth difference with respect to the third difference is equal to or greater than the predetermined value, the frequency difference f is calculated based on the relationship between the change amount and the sound pressure. An unpleasant threshold may be estimated.

  The auditory examination apparatus further includes a storage unit that holds a table indicating a relationship between the amount of change and an added value related to sound pressure, and the estimation unit refers to the table based on the amount of change and changes the amount of change. May be acquired, and the sum of the sound pressure c and the added value may be estimated as the unpleasant threshold value.

  The presentation order determining unit determines a presentation order so that each of the plurality of types of inspection sounds is presented a plurality of times, and the calculation unit adds evoked potentials induced by the inspection sounds having the same frequency and sound pressure. Thus, it may be extracted as an evoked potential induced by each inspection sound.

  The calculation unit may increase the number of times the evoked potential is added as the interval between the sound pressures of the plurality of inspection sounds is smaller.

  The calculation unit includes an extraction unit that extracts an evoked potential induced by each test sound, a negative component N1 that appears from the evoked potential about 100 milliseconds after the time when each test sound is presented, and An amplitude for calculating an N1-P2 amplitude that is an absolute value of a difference between the negative component N1 and the positive component P2 and an N1-P2 extraction unit that extracts a positive component P2 that appears after about 200 milliseconds from the time. A calculation unit, and the estimation unit listens from the N1-P2 amplitude at the frequency f based on the N1-P2 amplitude and a predetermined relationship between the N1-P2 amplitude and sound pressure. The comfortable range that is the range of sound pressure that can be performed and the discomfort threshold may be estimated.

  A hearing aid adjustment system according to an embodiment of the present invention includes the above-described hearing test apparatus, an acquisition unit that acquires a minimum audible value of a predetermined frequency, and a setting unit that sets a provisional discomfort threshold based on the minimum audible value And a hearing aid adjustment system comprising a characteristic setting unit and a hearing aid, wherein the test sound range setting unit of the hearing test apparatus is based on the minimum audible value acquired by the acquisition unit. The test sound is set, and the characteristic setting unit sets an input / output characteristic of the hearing aid based on the minimum audible value acquired by the acquisition unit and the unpleasant threshold estimated by the hearing test apparatus. May be.

  An auditory inspection method according to an embodiment of the present invention includes a step of setting a plurality of types of test sounds determined by a combination of at least three different sound pressures and at least two types of frequencies, and tests for the same frequency or the same sound pressure. Determining the order of presentation of the plurality of types of test sounds, outputting the plurality of types of test sounds in the determined order of presentation, and measuring the brain waves of the subject so that the sounds are not continuously presented The evoked potential induced by each test sound having the same frequency f and different sound pressures a, b, c (a <b <c) is extracted from the measured electroencephalogram, and the sound pressure a The latency or amplitude of the evoked potential A corresponding to the test sound of the sound pressure b, the latency or amplitude of the evoked potential B corresponding to the test sound of the sound pressure b, and the latency of the evoked potential C corresponding to the test sound of the sound pressure c. Ma Calculating the amplitude C, the first difference between the latency or amplitude of the evoked potential A and the latency or amplitude of the evoked potential B, and the latency or amplitude of the evoked potential B and the evoked potential. When a second difference between C latency and amplitude is calculated and the amount of change of the second difference with respect to the first difference is equal to or greater than a predetermined value, the predetermined amount of change and sound pressure are determined. And a step of estimating a discomfort threshold value at the frequency f based on the relationship between

  A computer program according to an embodiment of the present invention is a computer program executed by a computer provided in a hearing aid adjustment system, and the computer program is at least three types for a computer installed in the hearing aid adjustment system. The step of setting a plurality of types of inspection sounds defined by combinations of at least two types of sound pressures and different sound pressures, and the plurality of types of inspection sounds so as not to be continuously presented. A step of determining a presentation order; a step of outputting the plurality of types of test sounds in the determined presentation order; a step of receiving the measured brain waves of the subject; and a different sound at the same frequency f Induced by each inspection sound with pressure a, b, c (a <b <c) The evoked potential is extracted from the measured electroencephalogram, and the latency or amplitude of the evoked potential A corresponding to the test sound with the sound pressure a and the latency or amplitude of the evoked potential B corresponding to the test sound with the sound pressure b Calculating the latency or amplitude C of the evoked potential C corresponding to the test sound of the sound pressure c, and the first difference between the latency or amplitude of the evoked potential A and the latency or amplitude of the evoked potential B And a second difference between the latency or amplitude of the evoked potential B and the latency or amplitude of the evoked potential C is calculated, and a change amount of the second difference with respect to the first difference is not less than a predetermined value. If it is, a step of estimating a discomfort threshold at the frequency f based on a predetermined relationship between the change amount and the sound pressure is executed.

  According to the auditory test apparatus of the present invention, an evoked response to an auditory stimulus is measured, and a subject's discomfort threshold is estimated based on a correspondence relationship between the latency or amplitude of the evoked response and a sensory perception of loudness. can do. An unpleasant threshold is estimated from an evoked reaction when a plurality of test sounds are listened to within a range in which an unpleasant or dangerously loud sound can be heard without causing uncomfortable feeling. This makes it possible to obtain an unpleasant threshold suitable for adjusting the amplification factor of the hearing aid without causing the uncomfortable feeling of listening to too loud sound or the risk of deteriorating hearing loss due to repeated listening of too loud sound.

It is a block diagram of the auditory test apparatus 10 in Embodiment 1 of this invention. (A) is a figure which shows the electrode position defined in the international 10-20 method, (b) is a figure which shows the typical electrode position used for the measurement of an auditory evoked potential. It is a figure which shows the relationship between the volume of a sound shown by the nonpatent literature 3, and the latency and amplitude of N1. It is a figure which shows an example of the data (addition value) for estimation of the shortening range of the latency per sound pressure rise, and the unpleasant threshold value UCL stored in the intensity latency relationship storage unit 190. It is a flowchart which shows the operation | movement procedure of the auditory test apparatus 10 concerning Embodiment 1 of this invention. It is a block diagram which shows the detailed structure of the UCL estimation part 200 of the auditory test apparatus 10. FIG. It is a figure which shows typically an example of the process in which the test sound range determination part 110 sets the frequency of test sound, and the width of sound pressure. It is a graph which shows an example of the measurement result in the N1 latency in the example of FIG. It is a block diagram of the hearing aid adjustment system 15 concerning the modification of Embodiment 1 of this invention. It is a figure which shows typically the setting method of the sound pressure range of the test | inspection sound of the modification of Embodiment 1 of this invention. 10 is a flowchart showing a procedure of processing performed in the hearing aid adjustment system 15. It is a figure which shows the example of the discomfort threshold temporarily set according to the range of HTL. It is a graph of an example of the measurement result in the modification of Embodiment 1 of this invention. It is a block diagram of the auditory test apparatus 20 by Embodiment 2 of this invention. (A)-(c) is a figure which shows an example of the waveform of the measurement result of N1-P2. It is a figure which shows an example of the table which shows the relationship between the amplitude, the comfortable range, and the discomfort threshold value UCL which the intensity | strength amplitude relationship memory | storage part 390 has memorize | stored. It is a flowchart which shows the procedure of the process of the auditory test apparatus 20 concerning Embodiment 2 of this invention. It is a figure which shows typically an example of the process in which the test sound range determination part 110 sets the frequency of test sound, and the width of sound pressure. 19 is a graph illustrating an example of a measurement result of N1-P2 amplitude in the example of FIG. 4 is a flowchart showing a procedure of processing performed in the auditory test apparatus 20. It is a figure which shows an example of the table which showed the relationship between the space | interval of the sound pressure of test | inspection sound, and the addition frequency.

  Hereinafter, embodiments of a hearing test apparatus and the like according to the present invention will be described with reference to the accompanying drawings.

  The present invention is too large by utilizing the relationship between the response latency or amplitude of evoked potentials to auditory stimuli, which is a physiological response reflecting perceptual processing, and the perception of perceived loudness. Without listening to the sound, the discomfort threshold is estimated from the evoked potential when listening to the sound in the audible range.

  Human senses receive stimuli in a range suitable for their sensory receptors. Except in the acceptable range of areas close to the upper limit, the sense of stimulus size is often linear with the logarithm of the physical quantity of the stimulus. Hearing also has these characteristics. Except around the minimum audible value, which is the minimum audible value, and the surroundings where the sound is too loud to be perceived as sound, the sense of loudness is the energy of air vibration. Is approximately linear with the logarithm of The decibel (dB), which is a physical quantity of sound volume, is the energy of air vibration expressed logarithmically, and agrees well with the sense of human sound volume in a limited range.

  The inventors of the present application considered that the amplitude and latency of a component reflecting a relatively simple process in the auditory evoked potential is closely related to the sense of loudness. Non-Patent Document 3 shows that the amplitude and latency of the auditory evoked potential change depending on the volume of sound. This characteristic is shown in FIG. According to FIG. 3, the relationship between the loudness of the sound and the latency of the auditory evoked potential is linear in the middle region of the audible range. The inventors of the present application have found that the unpleasant threshold is estimated as the limit of the acceptable range by obtaining a boundary where the relationship between the loudness of the sound and the latency of the auditory evoked potential is not linear.

  “Auditory evoked potential” is a part of the electroencephalogram (EEG), which is a transient brain that occurs temporally in relation to an external event given to the auditory sense. It means potential fluctuation. In the present specification, an external event given to hearing refers to presentation of sound stimulation, that is, output of sound, for example, output of sound from an electroacoustic transducer. The electroacoustic transducer is, for example, a speaker, a headphone, an earphone or the like.

  The auditory evoked potential is a potential derived from the body surface. The auditory evoked potential is recorded as the potential difference between the vertex (Vertex) and the earlobe or temporal mastoid (mastoid). FIG. 2A shows the electrode positions defined in the International 10-20 Act. The crown is represented as Cz. FIG. 2B shows typical electrode positions used for the measurement of the auditory evoked potential. In this figure, the mastoid is present at the position labeled “5”. A ground electrode “Earth” is provided at the root of the nose. The potential at the top of the head is identified with reference to the potential of the reference electrode placed on the earlobe or mastoid. The potential thus identified is defined as the auditory evoked potential.

  The N1 component (hereinafter sometimes referred to simply as “N1”) is the peak of the negative component of the auditory evoked potential in the range of 80 milliseconds (ms) to 150 milliseconds (ms) from the point of presentation of the sound stimulus. In this specification, a time from 80 ms to 150 ms from a certain time point is sometimes described as “about 100 ms”. The N1 component may be referred to as “N100”.

  The P2 component (hereinafter, sometimes simply referred to as “P2”) is a peak of the positive component in the auditory evoked potential in the range of 160 ms or more and 250 ms or less from the point of presentation of the sound stimulus. P2 appears in time immediately after N1. In this specification, a time from 160 ms to 250 ms starting from a certain point in time may be described as “about 200 ms”. The P2 component may be referred to as “P200”.

  Since N1 and P2 appear consecutively in time, they may be treated as an N1-P2 complex wave (N1-P2 complex).

  In the present specification, the time from the presentation of the sound stimulus to the potential peak of each component is referred to as “latency” or “peak latency”.

  The latency of N1 is about 100 ms. The latency of P2 is about 200 ms. The N1-P2 amplitude indicates the absolute value of the difference between the peak potential of N1 and the peak potential of P2. Explain more clearly. The peak potential of N1 is a negative value. On the other hand, the peak potential of P2 is a positive value. The N1-P2 amplitude is the absolute value of the difference (negative) between the peak potential (negative) of N1 and the peak potential (positive) of P1, in other words, the absolute value of the peak potential (negative) of N1 and the peak potential of P2. (Positive) and sum.

  The latency of N1 is shortened when the loudness of the sound felt by the person is increased and becomes longer when the loudness of the sound felt by the person is decreased. The loudness that humans feel is called loudness. This loudness indicates a sense of human loudness. In a normal hearing person, in a certain range of the audible range, it corresponds approximately linearly to the logarithm of sound energy.

  FIG. 3 shows the relationship between the loudness and the latency and amplitude of N1 shown in Non-Patent Document 3. The solid line in FIG. 3 shows the relationship between the loudness and the magnitude of the N1-P2 amplitude. The dotted line in FIG. 3 shows the relationship between the loudness of the sound and the latency of N1.

  The horizontal axis of FIG. 3 is dBSL (Sensation Level). The sound pressure is displayed as a dB value where the minimum audible value of the subject is 0 dB. In the vertical axis of FIG. 3, the left display indicates the magnitude of the N1-P2 amplitude in microvolts. The display on the right shows the latency of N1 in milliseconds (ms).

  Here, an experiment is performed using a test sound having a frequency of 1000 Hz with a normal hearing person as a subject. Hereinafter, the test sound presented to the subject is also referred to as “auditory stimulus” or “sound stimulus”.

  When the subject is a normal hearing person and the frequency of the test sound is 1000 Hz, it is known that the discomfort threshold is 90 dB or more and 100 dB or less. Therefore, the unpleasant threshold of the normal hearing person is larger than 90 dBSL at the right end of the figure.

  In the range from 10 dBSL to 90 dBSL, the amplitude indicated by the solid line increases relatively linearly. On the other hand, in the range from 10 dBSL to 30 dBSL, the latency indicated by the dotted line is steeply shortened. In the range from 30 dBSL to 70 dBSL, the latency is relatively linearly shortened. For sounds larger than 70 dBSL, the latency is reduced with increasing sound pressure of the inspection sound. For a normal hearing person, 30 dBSL is slightly smaller than an easily audible size, and 70 dBSL is an upper limit of an easily audible range. When it becomes larger than 70 dBSL, the normal hearing person starts to feel a loud sound. According to FIG. 3, it is possible to determine whether the size of the inspection sound is in an easily audible range or larger or smaller than the easily audible range by looking at the amount of change in the N1 latency with respect to the increase in the size of the inspection sound. It is.

  Until now, auditory evoked potentials have been examined for the purpose of screening for hearing loss and diagnosis of hearing loss. Regarding the amount of sensation above the threshold, only a few examples using the auditory evoked potential are used to examine the presence or absence of the recruitment phenomenon seen in the hearing impaired.

  However, in the conventional methods for measuring auditory function, there has been no viewpoint for estimating the auditory state of the subject using the correspondence between the auditory evoked potential and the sensory amount on the threshold. The inventor of the present application pays attention to the relationship between the N1 latency and the amount of sensation above the threshold, and estimates the loudness that cannot be tolerated by measuring the loudness of the upper limit of the easy-to-hear range. I found that it was possible.

  Specifically, the inventors of the present application paid attention to a range of sound volume that is easy to hear. And, instead of sequentially increasing the value of the inspection sound, multiple inspection sound pressure ranges are set to present the inspection sound randomly, and the inspection sound obtained in response to the presentation is raised Based on the change in the characteristic of N1, a change in the sense of size is determined.

  N1 corresponds to the amount of sound perception above the threshold. However, the latency and amplitude of N1 change depending on other conditions. When the same sound continues, habituation occurs. If it is a pure tone inspection sound, it will become accustomed to continuous sound of the same frequency, and the amplitude will be reduced. Therefore, the inventors of the present application kept the measurement accuracy by presenting the inspection sound of the same frequency without repetition. Similarly, regarding the sound pressure, the inventors of the present application decided not to gradually increase the sound pressure but to present it with a random sound pressure. Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  In the following description of the embodiment, “inspection sound” and its “frequency” are referred to. In the present specification, the inspection sound may be a pure sound or a narrow band noise. When the inspection sound is a pure sound, the frequency of the inspection sound is the frequency of the pure sound. When the inspection sound is narrow band noise, the frequency of the inspection sound may be handled as the center frequency of the noise.

(Embodiment 1)
FIG. 1 shows a configuration diagram of a hearing test apparatus 10 according to the first embodiment.

  The auditory test apparatus 10 measures an evoked response to an auditory stimulus, and estimates a subject's discomfort threshold based on the correspondence between the latency or amplitude of the evoked response and a perceptual sound volume sensation. At this time, the subject does not have to listen to unpleasant loud sounds or dangerous loud sounds that may impair the auditory function. Just listen. The hearing test apparatus 10 estimates a discomfort threshold based on a test subject's evoked response to a test sound (auditory stimulus). This makes it possible to obtain an unpleasant threshold value suitable for adjusting the amplification factor of the hearing aid without giving the subject an uncomfortable feeling of listening to too loud sound or a risk of deterioration of hearing loss caused by repeatedly listening to too loud sound. .

  The hearing test apparatus 10 is used for a test related to determination of a discomfort threshold of a subject or a patient, for example, in a hearing aid store or an otolaryngology department. Note that the hearing test apparatus 10 may be incorporated in an audiometer for performing a hearing test.

  Hereinafter, the configuration of the hearing test apparatus 10 will be described.

  The auditory examination apparatus 10 of the present embodiment includes an examination sound range determination unit 110, a presentation order determination unit 120, an examination sound signal generation unit 130, an examination sound output unit 140, an electroencephalogram measurement unit 150, and an evoked potential extraction unit. 160, an N1 determination unit 170, a latency calculation unit 180, an intensity latency relationship storage unit 190, a UCL estimation unit 200, and a calculation unit 300.

  The inspection sound range determination unit 110 sets the frequency of the inspection sound and the range of the presented sound pressure.

  The presentation order determination unit 120 determines the frequencies and sound pressures of a plurality of inspection sounds within the range set by the inspection sound range determination unit 110, and determines the order in which the inspection sounds are presented.

  The inspection sound signal generation unit 130 generates an inspection sound signal.

  The inspection sound output unit 140 outputs the inspection sound signal as the inspection sound.

  The electroencephalogram measurement unit 150 is a so-called electroencephalograph, and acquires an electroencephalogram through an electrode installed on the scalp or the like of the subject 100.

  The calculation unit 300 includes an evoked potential extraction unit 160, an N1 determination unit 170, and a latency calculation unit 180. The arithmetic unit 300 may be realized as an integrated circuit chip, for example.

  The evoked potential extraction unit 160 extracts an evoked potential from the electroencephalogram signal.

  The N1 determination unit 170 extracts N1, which is a negative potential with a latency of about 100 ms.

  The latency calculation unit 180 measures the latency of N1.

  The intensity latency relationship storage unit 190 stores the correspondence between the sound volume and the N1 latency.

  The UCL estimation unit 200 estimates an uncomfortable level (hereinafter also referred to as “UCL”) from the measured N1 latency based on the correspondence stored in the strength latency relationship storage unit 190.

  The inspection sound range determination unit 110 includes a frequency setting unit 111 and a sound pressure setting unit 112. The test sound range determination unit 110 receives the measurement support information, sets a plurality of types of test sound frequencies with the frequency setting unit 111, and sets a plurality of sound pressures for each frequency with the sound pressure setting unit 112. Sets the sound pressure range of the sound.

  The presentation order determination unit 120 includes a sound pressure determination unit 121 and an order determination unit 122. The sound pressure determining unit 121 determines a plurality of sound pressures for each frequency of the test sound to be presented within the range of the test sound frequency and the sound pressure set by the test sound range determining unit 110. The order determination unit 122 determines the order in which inspection sounds are presented.

  The inspection sound signal generation unit 130 generates an inspection sound signal based on the frequency and sound pressure of the inspection sound determined by the presentation order determination unit 120.

  The inspection sound output unit 140 outputs the inspection sound signal generated by the inspection sound signal generation unit 130 as an acoustic signal in accordance with the inspection sound presentation order determined by the presentation order determination unit 120.

  The evoked potential extraction unit 160 extracts the evoked potential induced by listening to the test sound from the electroencephalogram signal acquired by the electroencephalogram measurement unit 150.

  The N1 determination unit extracts N1, which is a negative potential having a latency of about 100 ms, from the evoked potentials extracted by the evoked potential extracting unit 160.

  The hearing test apparatus 10 includes a test sound range determination unit 110, a presentation order determination unit 120, a test sound signal generation unit 130, an evoked potential extraction unit 160, an N1 determination unit 170, an N1 latency calculation unit 180, and a UCL estimation unit 200. Is realized by, for example, a single or a plurality of computers and memories. The intensity latency relationship storage unit 190 is realized by a single memory, for example.

  Based on the characteristics of N1 as described above, the UCL estimation unit 200 obtains the latency reduction width measured by the latency calculation unit 180. The shortening width is a shortening width of the latency with respect to the increase of the sound pressure of the inspection sound, for example, a shortening width of the latency for every 10 dB of sound pressure increase.

  Comparing the reduction range of the latency due to the increase in sound pressure, for example, the reduction range of the latency from 90 dBPL to 100 dBPL is 20% compared to the reduction range from 90 dBSPL ("Sound pressure level") to 90 dBSPL. If it becomes smaller than this, it is considered that the shortening range of the latency is reduced. At this time, among the two types of test sound ranges, the range of the test sound having a large sound pressure, in the above example, from 90 dBSPL to 100 dBSPL, and the sound pressure range in which the reduction range for the increase in the sound pressure is small. The unpleasant threshold value is estimated according to the latency reduction width per unit sound pressure increase (for example, the latency reduction width per 10 dB sound pressure increase). In the above example, the discomfort threshold is estimated in accordance with the latency reduction range from 90 dBSPL to 100 dBSPL.

  FIG. 4 shows an example of the correspondence relationship between the shortening range of the latency per increase in sound pressure and the data (addition value) for estimating the unpleasant threshold UCL stored in the intensity latency relationship storage unit 190.

  As shown in FIG. 4, in the present embodiment, for example, an added value for estimating the unpleasant threshold value UCL is set according to the shortening range of the latency per 10 dB sound pressure increase. The UCL estimation unit 200 uses the data shown in FIG. 4 to add the added value corresponding to the shortening width to the sound pressure of the test sound whose latency shortening width is reduced to obtain the unpleasant threshold value UCL.

  For example, the case where the latency reduction range from 90 dBSPL to 100 dBSPL is smaller than the latency reduction range when the sound pressure is smaller than that will be described as an example. In the case where the latency at 100 dBSPL is 3 ms shorter than the latency at 90 dBSPL, the UCL estimation unit 200 determines the addition value as 10 dB according to the table of FIG. The UCL estimation unit 200 adds an added value of 10 dB to 100 dBSPL, which is a sound pressure that has been confirmed to reduce the latency, and estimates 110 dBSPL as an unpleasant threshold UCL.

  Another example will be described with reference to the graph shown in FIG. According to FIG. 3, the latency is 100 ms for the inspection sound of 50 dBSL, 96 ms for the inspection sound of 60 dBSL, and 92 ms for the inspection sound of 70 dBSL. Accordingly, the latency reduction width corresponding to the increase in sound pressure from 50 dBSL to 60 dBSL is 4 ms, and the latency reduction width corresponding to the increase in sound pressure from 60 dBSL to 70 dBSL is also 4 ms, and the reduction width does not change.

  However, the latency with the test sound of 80 dBSL is 89 ms, and the latency reduction width corresponding to the increase in sound pressure from 70 dBSL to 80 dBSL is 3 ms. This is 25% smaller than the latency reduction width of 4 ms corresponding to a sound pressure increase from 60 dBSL to 70 dBSL. Here, the UCL estimation unit 200 refers to the table of FIG. 4 based on the fact that the shortening width is 3 ms per 10 dB, and sets the added value to 10 dB. In this example, the UCL estimation unit 200 adds 10 dB to 80 dBSL and estimates the uncomfortable threshold as 90 dBSL because the sound pressure increase from 70 dBSL to 80 dBSL decreases the latency.

  Note that it is not necessary to estimate a sound pressure range that is low enough that a healthy person does not feel uncomfortable as a candidate for a discomfort threshold. Such a low sound pressure range may be set to a range lower than 40 dBSPL, for example, and the above-described latency reduction width may be obtained for a sound pressure range of 40 dBSPL or more to estimate a discomfort threshold. As a result, the amount of processing can be reduced, and the unpleasant threshold value UCL can be accurately identified.

  Next, the operation of the auditory test apparatus configured as described above will be described with reference to FIGS. 5, 7, and 8. FIG.

  FIG. 5 is a flowchart showing an operation procedure of the hearing test apparatus 10 according to the present embodiment.

  When the hearing test apparatus 10 starts operating, first, the test sound range determination unit 110 receives input of measurement instruction information and starts measurement (S1000). The measurement instruction information is input from a system external to the hearing test apparatus 10 or input from an operation input unit. The measurement instruction information may include information on the frequency at which the discomfort threshold UCL is to be measured.

  The frequency setting unit 111 of the inspection sound range determination unit 110 determines a plurality of frequencies of the inspection sound (S1010). The frequency setting unit 111 determines a frequency at which the discomfort threshold UCL is to be measured among a plurality of predetermined frequencies. If the measurement instruction information input to the inspection sound range determination unit 110 in step S1000 includes information specifying the measurement frequency, the frequency setting unit 111 determines the frequency specified in the measurement instruction information as the frequency of the inspection sound. . On the other hand, when the measurement instruction information does not include information specifying the measurement frequency, the frequency setting unit 111 determines five frequencies, for example, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz, as the frequencies of the inspection sound. To do.

  The sound pressure setting unit 112 sets the range of the sound pressure of the inspection sound for each frequency of the inspection sound determined in step S1010 (S1015). A method for setting the sound pressure range of the inspection sound will be described later.

  The sound pressure determining unit 121 of the presentation order determining unit 120 receives the frequency of the test sound and the range of the sound pressure set by the test sound range determining unit 110 as input, and for each frequency specified as the test sound, A plurality of inspection sounds having different sound pressures within the pressure range are set (S1020).

  The order determination unit 122 determines the order in which the inspection sounds are presented for all the inspection sounds that have been set (S1025). At this time, the order determination unit 122 sets the number of additions when extracting the evoked potentials by averaging to, for example, 20 times, so that the same frequency does not continue for all stimulation sounds including this repetition. Assign a random order.

  When the same stimulus sound is repeated in a short time, the amplitude of the N1-P2 component is supposed to decrease rapidly according to the repetition. Therefore, different stimuli need to be presented in an unpredictable order. As an order assignment method, for example, the order determination unit 122 arbitrarily selects the first inspection sound, and the second and subsequent inspection sounds have the same frequency as the first inspection sound among the remaining inspection sounds. Select any of the inspection sounds except for. This may be repeated to determine the entire order.

  Next, the inspection sound signal generation unit 130 generates a signal of each of the plurality of inspection sounds whose frequencies and sound pressures are determined in steps S1015 and S1020. The inspection sound output unit 140 sequentially presents the inspection sound generated by the inspection sound signal generation unit 130 to the subject 100 according to the order of presentation determined in step S1025. The inspection sound output unit 140 outputs information on the inspection sound output timing to the electroencephalogram measurement unit 150 simultaneously with the output of the inspection sound. The electroencephalogram measurement unit 150 measures an electroencephalogram from an electrode mounted on the skin of the subject 100 (S1030).

  As a method for presenting the test sound during the electroencephalogram measurement, for example, the test sound presentation time interval is set to an arbitrary time width between 500 ms and 1 second. However, it is assumed that the time width is randomly changed each time. The inspection sound is presented to one ear using, for example, headphones. In the electroencephalogram measurement, for example, the electroencephalogram measurement electrode is attached to the vertex (Vertex), that is, the Cz of the international 10-20 method (FIG. 2A), and the reference electrode is placed on the mastoid process of temporal bone In addition, a biological earth electrode is attached to the nasal root, and the potential difference between the measurement electrode and the reference electrode is measured as an electroencephalogram.

  The measurement time continues, for example, in a period from 500 ms before presentation of the first inspection sound to 500 ms after presentation of the last inspection sound.

  The evoked potential extraction unit 160 extracts an evoked potential for each type of test sound from the electroencephalogram measured by the electroencephalogram measurement unit 150 (S1040). The type of inspection sound is classified by the frequency of the inspection sound and the sound pressure of the inspection sound. Test sounds having the same frequency and the same sound pressure are regarded as the same type of test sound.

  The procedure for extracting the evoked potential is, for example, as follows. The evoked potential extraction unit 160 first cuts out an electroencephalogram waveform having a time width of −100 ms to 300 ms with the test sound presentation start time set to 0 (starting point). For the cut out electroencephalogram waveform, the evoked potential extraction unit 160 obtains an average potential in a section from −100 ms to 0 ms, and shifts the entire waveform so that the obtained average potential becomes 0 volts. The evoked potential extraction unit 160 collects the electroencephalogram waveforms for each of the same type of test sounds, and adds and averages the electroencephalogram waveforms on the time axis where the test sound presentation start time is zero. In the present embodiment, the evoked potential extraction unit 160 averages the brain wave waveforms for 20 times. The electroencephalogram waveform obtained by the arithmetic mean operation is adopted as the electroencephalogram waveform (evoked potential waveform) of the target inspection sound.

  From the evoked potential for each type of test sound extracted by the evoked potential extracting unit 160 in step S1040, the N1 determining unit 170 extracts an N1 component that is an auditory evoked potential. The latency calculation unit 180 obtains the latency of N1 extracted by the N1 determination unit 170 (S1050). The latency of N1 is about 100 ms from the above starting point. In the present embodiment, the N1 determination unit 170 extracts the negative maximum value in the electroencephalogram waveform as the N1 component between 80 ms and 200 ms when the test sound presentation start time is 0.

  The latency calculation unit 180 sets the time when the negative shows the maximum value as the latency of N1 as a time represented by a position (elapsed time) on the time axis where the test sound presentation start time is 0.

  Next, the NCL latency obtained by the latency calculation unit 180 in step S1050 is compared with the UCL estimation unit 200 for each frequency of the test sound, and the latency reduction width corresponding to the increase in the sound pressure of the test sound is obtained. It is determined whether or not the image has been reduced beyond a certain level. When the latency reduction width is reduced, the UCL estimation unit 200 stores the sound pressure and the latency reduction width for which the reduction of the latency reduction width is recognized for each frequency. It is determined whether or not the sound pressure and the latency reduction width in which the reduction of the latency reduction width is recognized at all frequencies of the inspection sound are stored (S1060).

  FIG. 6 is a block diagram illustrating a detailed configuration of the UCL estimation unit 200 of the hearing test apparatus 10. The UCL estimation unit 200 includes a calculation interval setting unit 201, a latency reduction width calculation unit 202, a latency reduction width comparison unit 203, a sound pressure identification unit 204, a storage unit 205, and an estimation unit 206. ing.

  The latency reduction width is, for example, the reduction width of the latency per 10 dB of sound pressure increase for the N1 latency corresponding to each sound pressure for each frequency of the inspection sound. In this embodiment, the calculation interval of the latency reduction width is set between the inspection sounds having the closest sound pressures. In the calculation section of the adjacent latency reduction width, the latency reduction width is smaller when the reduction width is, for example, 20% or more smaller than the latency reduction width in the section where the sound pressure is high in the section where the sound pressure is low. It is considered to have become.

  FIG. 7 schematically illustrates an example of a process in which the inspection sound range determination unit 110 sets the frequency of the inspection sound and the width of the sound pressure. FIG. 8 is a graph showing an example of the measurement result of the N1 latency in the example of FIG. Hereinafter, the details of the processing in step S1060 of FIG. 5 will be described in detail together with the operations of the components of the UCL estimation unit 200 shown in FIG.

  For example, in FIG. 8, the sound pressures of 70 dBSPL, 80 dBSPL, and 90 dBSPL are set for the inspection sounds of 500 Hz and 1000 Hz. The calculation interval setting unit 201 of the UCL estimation unit 200 sets two adjacent intervals of the interval from 70 dBSPL to 80 dBSPL and the interval from 80 dBSPL to 90 dBSPL as the calculation interval of the latency reduction width. The latency reduction width calculation unit 202 obtains the latency reduction width in the section from 70 dBSPL to 80 dBSPL and the latency reduction width in the section from 80 dBSPL to 90 dBSPL. The latency reduction width comparison unit 204 compares the latency reduction width in the section from 70 dBSPL to 80 dBSPL with the latency reduction width in the section from 80 dBSPL to 90 dBSPL.

  As described above, the latency of N1 is shortened when the loudness of the sound felt by the person is increased, and is increased when the loudness of the sound felt by the person is decreased. Therefore, the reduction in the latency reduction width means that the loudness felt by the subject is increasing. Therefore, by comparing the latency reduction widths of adjacent sound pressure sections, it can be determined whether or not the volume of sound felt by the subject is large.

  In the example of the present specification, since the sound pressure increases in both sections are both 10 dB, the latency reduction width calculation unit 202 calculates the N1 latency for the 70 dB SPL inspection sound and the N1 latency for the 80 dBPL inspection sound. The difference is defined as a latency reduction width with respect to a 10 dB width that is a unit sound pressure increase width. Similarly, also in the interval from 80 dBSPL to 90 dBSPL, the latency reduction width calculation unit 202 calculates the difference between the N1 latency for the 80 dBSPL test sound and the N1 latency for the 90 dBPL test sound with respect to the unit sound pressure increase width of 10 dB. Calculated as the latency reduction width.

  The latency shortening width comparison unit 204 compares the latency shortening widths of both sections and determines a reduction amount of the shortening width.

  An example of 4000 Hz in FIG. 8 will be described. In this example, in addition to 70, 80, and 90 dBSPL, 95 dBSPL, 99 dBSPL, and 101 dBSPL are set as the sound pressure of the inspection sound. In this case, the calculation interval setting unit 201 sets the interval from 95 dBSPL to 99 dBSPL and the interval from 99 dBSPL to 101 dBSPL as the calculation interval of the latency reduction width related to the sound pressures of 95 dBSPL, 99 dBSPL, and 101 dBSPL. Since the increase in sound pressure in both sections is 4 dB and 2 dB, the latency reduction width calculation unit 202 sets the difference between the N1 latency for the 99 dBSPL inspection sound and the N1 latency for the 95 dBSPL inspection sound as 2. Multiply by 5 to obtain a shortened width per 10 dB that is a unit sound pressure increase width. Similarly, the difference between the N1 latency for the 101 dBSPL test sound and the N1 latency for the 99 dBPL test sound is multiplied by 5 to obtain a shortened width per 10 dB, which is the unit sound pressure increase width, and the two sections are compared and the shortened width Determine the amount of reduction.

  The sound pressure identification unit 204 regards the maximum sound pressure of the section determined that the latency reduction width is reduced as the sound pressure with the latency reduction width reduced, and uses the sound pressure and the latency reduction width as the frequency. Are stored in the storage unit 205 as a sound pressure with a reduced latency reduction width and a latency reduction width.

  The estimation unit 206 refers to the storage unit 205 to determine whether or not there remains an inspection sound frequency for which the sound pressure at which the shortening range of the N1 latency is reduced is not determined.

  If it is determined in step S1060 that the sound pressure with which the reduction width of the N1 latency with respect to the increase in sound pressure is reduced is determined for all inspection sound frequencies, the process proceeds to step S1070. On the other hand, if there remains an inspection sound frequency for which the sound pressure at which the N1 latency reduction width with respect to the increase in sound pressure is reduced is not determined, the process proceeds to step S1065.

  In step S1065, the frequency setting unit 111 sets an uninspected frequency among the frequencies of the inspection sound determined in step S1010. Then, the same process is performed again from step S1015.

  The estimation unit 206 estimates the discomfort threshold with reference to the table (FIG. 4) held in the intensity latency relationship storage unit 190 (S1070). Specifically, the UCL estimation unit 200 extracts, for each inspection sound, the sound pressure at which the shortening range for the N1 latency is reduced and the shortening range for the latency per 10 dB increase in sound pressure at that time. Then, with reference to the table held in the intensity latency relationship storage unit 190 with the extracted shortening range of the latency, an addition value used for estimation of the discomfort threshold is obtained. Thereafter, the UCL estimation unit 200 adds each added value to the sound pressure value (for example, the maximum sound pressure value included in the sound pressure range) in which the shortening range of the N1 latency with respect to the increase in sound pressure is reduced, and the sound Determine the discomfort threshold for pressure. The UCL estimation unit 200 estimates that the largest value among the obtained discomfort thresholds is the discomfort threshold UCL for the frequency.

  The UCL estimation unit 200 outputs the unpleasant threshold value for each inspection sound frequency estimated in step S1070 as an estimation result. The UCL estimation unit 200 outputs the display to a display device such as a display, for example, displays an unpleasant threshold value for each frequency of the inspection sound (S1080), and ends the process.

  It can be said that the inspection sound range determination unit 110 sets the sound pressure range of the inspection sound by satisfying a predetermined condition at the frequency at which the discomfort threshold is to be measured. The predetermined conditions are the following conditions 1) to 3). That is, 1) It is within the range of the sound pressure that is smaller than the assumed discomfort threshold. 2) A measurement result can be acquired with at least three or more different sound pressures in a series of measurements including measurement at one or more previous sound pressure range settings. 3) When the sound pressure range is set a plurality of times, the sound pressure range is set within a sound pressure range larger than the sound pressure range set when the preceding sound pressure range is set.

  Next, the details of each step in FIG. 5 will be described more specifically with reference to FIGS. 7 and 8 again.

  Details of the operation of the inspection sound range determination unit 110 in step S1010 will be described. In the example of FIG. 7, the frequencies to be measured are 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz. Since the unpleasant threshold value for a normal hearing person is about 100 dBSPL, first, as a first sound pressure range setting, a sound pressure range smaller than 100 dBSPL is set for each frequency according to the condition of 1).

  Also, since the discrimination threshold for the loudness of a normal hearing person is about 1 dB, it is set within a sound pressure range with a width of 2 dB or more so that three or more kinds of test sound pressures can be set according to the condition of 2). To do. In the specification of the present application, the “discrimination threshold” refers to the minimum stimulus difference that can sense the difference when the stimulus by sound is changed.

  In the example of FIG. 7, the initial sound pressure setting is performed by setting the range of the sound pressure level (vertical axis) from 70 dBSPL to 90 dBSPL for each frequency (horizontal axis) as indicated by a white arrow. In step S1020, the sound pressure determination unit 121 determines, for example, the output sound pressures of 70 dBSPL, 80 dBSPL, and 90 dBSPL for each of the five types of frequencies according to the sound pressure range of the inspection sound. Thereby, in this example, 15 types of inspection sounds are set. Furthermore, repeated measurements for 20 averaging operations are set for each of the 15 types of inspection sounds. The inspection sound is set 300 times in total for the setting of the frequency and sound pressure range of the first inspection sound.

  With respect to the frequency and sound pressure range of the inspection sound set for the first time, N1 latencies for 15 types of inspection sounds are obtained in steps S1030, S1040, and S1050. In step S1060, the latency reduction width comparison unit 203 of the UCL estimation unit 200 compares the latency reduction width corresponding to the increase in sound pressure at each frequency.

  As an example, assume that the N1 latency as shown in FIG. 8 is obtained for the first 70 dBSPL, 80 dBSPL, and 90 dBSPL inspection sounds.

  Attention is now paid to the N1 latency at a frequency of 500 Hz. The latency is shortened by 5 ms for a sound pressure increase from 70 dBSPL to 80 dBSPL, and the latency is shortened by 3 ms for a sound pressure increase from 80 dBSPL to 90 dBSPL. Therefore, it can be seen that the latency reduction range from 80 dBSPL to 90 dBSPL is 40% smaller than the latency reduction range from 70 dBSPL to 80 dBSPL. Since the reduction amount (ratio) of the shortening width exceeds 20%, the sound pressure specifying unit 204 regards 90 dBSPL as the sound pressure with the shortening width at the N1 latency reduced.

  Also, for 1000 Hz, a sound pressure with a reduced width of the N1 latency can be specified by the same method. Specifically, at a frequency of 250 Hz, the latency is shortened by 6 ms for an increase in sound pressure from 70 dBSPL to 80 dBSPL, and the latency is shortened by 5 ms for an increase in sound pressure from 80 dBSPL to 90 dBSPL. The latency reduction range from 80 dBSPL to 90 dBSPL is 17% smaller than the latency reduction range from 70 dBSPL to 80 dBSPL. Since the reduction amount (ratio) of the shortening width does not exceed 20%, the sound pressure specifying unit 204 cannot determine the sound pressure with the shortening width at the N1 latency reduced at 250 Hz. Similarly, at 2000 Hz and 4000 Hz, it is impossible to determine the sound pressure in which the shortening range of the N1 latency is reduced.

  Therefore, in the example of FIGS. 7 and 8, for the frequency of 2000 Hz and 4000 Hz, the determination result in step S1060 is “No” for the range of the first inspection sound. As a result, the process proceeds to step S1065, and the frequency setting unit 111 sets an uninspected frequency.

  Then, the process returns to step S1010, and the sound pressure setting unit 112 sets the sound pressure range of the second inspection sound. Specifically, it is as follows.

  Since the sound pressure in which the reduction width of the N1 latency of 500 Hz and 1000 Hz is reduced in the first inspection sound range is determined, the sound pressure setting unit 112 is set in the setting of the frequency and sound pressure range of the second inspection sound. , 250 Hz, 2000 Hz, and 4000 Hz are set, in which the sound pressure with the reduced width of the N1 latency reduced for the first time was not determined. For the sound pressure, the sound pressure setting unit 112 sets a sound pressure range that satisfies the above three conditions. Specifically, the sound pressure setting unit 112 performs a test with a sound pressure difference of 1 dB or more including the first test sound in the sound pressure range smaller than 100 dBSPL according to the condition of 1) and according to the condition of 2). The sound pressure range is set in a sound pressure range in which three or more types of sounds can be set and in a sound pressure range greater than 90 dBSPL in accordance with the above condition 3).

  In the example of FIG. 7, the sound pressure setting unit 112 sets a range from 91 dBSPL to 99 dBSPL for 250 Hz, 2000 Hz, and 4000 Hz, respectively, as indicated by black arrows. According to the set sound pressure range of the inspection sound and the maximum sound pressure of the inspection sound set for the first time, the sound pressure of the inspection sound is determined for each of the three types of frequencies in step S1020.

  For example, the sound pressure setting unit 112 divides the 8 dB sound pressure range from 91 dBSPL to 99 dBSPL, which is set as the range of the second inspection sound, into two, and sets the sound pressure of the inspection sound to 95 dBSPL and 99 dBSPL. When these sound pressures are applied to 250 Hz, 2000 Hz, and 4000 Hz, six types of inspection sounds can be set. At 250 Hz, 2000 Hz, and 4000 Hz, measurement of five sound pressure test sounds is performed together with the first measurement. For each of the six types of test sounds in the second measurement, repeated measurement for 20 averages is set. Accordingly, 120 test sound presentations are set for the setting of the frequency and sound pressure range of the second test sound.

  As in the first time, the latency of N1 with respect to six types of inspection sounds is obtained by the operations from step S1030 to step S1050. As shown in FIG. 8, for 250 Hz, the N1 latency was 98 ms for both sound pressures of 95 dBSPL and 99 dBSPL. Since the latency of N1 with respect to 90 dBSPL at the time of the first measurement was 99 ms, the latency reduction corresponding to the increase in sound pressure from 90 dBSPL to 95 dBSPL is 1 ms, and 2 ms per 10 dB. On the other hand, the latency reduction width corresponding to the increase in sound pressure from 80 dBSPL to 90 dBSPL was 5 ms. Therefore, the reduction amount (ratio) of the shortening width is 20% or more. Therefore, the sound pressure identification unit 204 determines the sound pressure with the reduced width of the N1 latency at 250 Hz as 95 dBSPL.

  At the next 2000 Hz, the N1 latency for the 95 dBSPL test sound was 102 ms and for 99 dBSPL it was 100 ms. The latency reduction corresponding to the increase in sound pressure from 90 dBPL to 95 dBPL is 3 ms, and 6 ms per 10 dB. The latency reduction corresponding to the increase in sound pressure from 95 dBSPL to 99 dBSPL is 2 ms, and 5 ms per 10 dB. Since there is no section in which the reduction amount (ratio) of the shortening width with respect to the increase in sound pressure is 20% or more, the sound pressure specifying unit 204 cannot determine the sound pressure in which the shortening width at the N1 latency at 2000 Hz is reduced. The same applies to 4000 Hz. Therefore, it is determined as No again in step S1060, and the hearing test apparatus 10 executes the processes of steps S1065 and S1015.

  In the second sound pressure range, the sound pressure at which the shortening width of the 250 Hz N1 latency was reduced was determined. For this reason, in the third setting of the frequency of the inspection sound (step S1065), 2000 Hz and 4000 Hz are set, in which the sound pressure with the reduced width of the N1 latency is not determined. Regarding the sound pressure, in step S1015, the sound pressure setting unit 112 changes the assumed discomfort threshold to, for example, 102 dBSPL because the sound pressure with the reduced N1 latency shortened by 100 dB assumed at the beginning has not been determined. According to the condition 1), the sound pressure setting unit 112 sets a sound pressure range smaller than 102 dBSPL. According to the condition 2), the sound pressure setting unit 112 sets a sound pressure range having a width of 1 dB or more so that three or more types of sound pressure can be set including the first and second inspection sounds. According to the condition of 3), the sound pressure setting unit 112 sets a sound pressure range larger than 99 dBSPL.

  In the example of FIG. 7, the sound pressure setting for the third time sets a range from 100 dBSPL to 101 dBSPL with respect to 2000 Hz and 4000 Hz as indicated by a half-tone arrow. In accordance with the sound pressure range of the inspection sound, the sound pressure determination unit 121 determines the sound pressure of the inspection sound for each of the two types of frequencies in step S1020. In the example of FIGS. 7 and 8, the maximum sound pressure of the second test sound is 99 dBSPL, and the sound pressure interval is 5 dB and 4 dB including the first maximum sound pressure test sound. Here, for example, since the range of the sound pressure in the setting range is as narrow as 1 dB, the sound pressure determination unit 121 sets two types of inspection sounds, 2000 Hz and 4000 Hz, with the sound pressure of the inspection sound being 101 dBSPL. The sound pressure determination unit 121 performs a total of 40 test sounds with respect to the setting of the frequency and sound pressure range of the third test sound, so that repeated measurement for 20 averages is performed for each of the two types of test sounds. Set to present.

  Similar to the first time and the second time, the latency of N1 with respect to two types of inspection sounds is obtained by the processing from step S1030 to step S1050. Since the inspection sound does not continuously output inspection sounds having the same frequency, two types of inspection sounds are alternately output. The presenting order is determined by the order determining unit 122 in step S1025. As shown in FIG. 8, the N1 latency for the 101 dBSPL test sound is the same as the N1 latency for the 99 dBSPL test sound at both 2000 Hz and 4000 Hz, and the reduction amount (ratio) of the shortening width is 20% or more. As a result, the sound pressure in which the shortening width of the N1 latency at 2000 Hz and 4000 Hz is reduced is determined to be 101 dBSPL. Since the sound pressure with the reduced N1 latency is reduced for all frequencies, the process proceeds to step S1070 as a result of the branch determination in step S1060.

  In step S1070, the estimation unit 206 of the UCL estimation unit 200 estimates the discomfort threshold UCL based on the relationship of FIG. 4 stored in the intensity latency relationship storage unit 190. In the example of FIGS. 7 and 8, the estimation unit 206 adds an added value of 5 dB corresponding to the latency reduction width of 3 ms to 90 dBSPL for 500 Hz and 1000 Hz, and sets the unpleasant threshold value to 95 dBSPL. For 250 Hz, the estimation unit 206 adds 4 dB corresponding to the latency reduction width of 2 ms per 10 dB to 95 dBSPL, and sets the discomfort threshold to 99 dBSPL. Then, the estimation unit 206 adds 1 dB corresponding to the latency reduction width 0 ms per 10 dB to 101 dBSPL for 2000 Hz and 4000 Hz, and sets the discomfort threshold to 102 dBSPL.

  As described above, the auditory test apparatus 10 presents a plurality of test sounds having different frequencies within a certain sound pressure range in an arbitrary order without continuously presenting test sounds having the same frequency. The range of the sound pressure of the test sound is sequentially increased, and the sound pressure at which the shortening range of the latency of the auditory evoked potential N1 decreases with respect to the increase of the sound pressure of the test sound is determined. A discomfort threshold value that is larger than the sound pressure of the test sound presented from the correspondence with the sound pressure is estimated. As a result, the unpleasant threshold value can be determined by the test sound having a sound pressure equal to or lower than the unpleasant threshold value, and the burden on the subject to listen to an unacceptably large test sound can be reduced.

  In the first embodiment, the discomfort threshold value UCL of up to three of the five frequencies is estimated in the first and second test sound range measurements, and the third test sound range is determined in step S1010. An example has been described in which two frequencies are specified as frequencies that require measurement, and two frequencies are set as the inspection sound range. However, in step S1060, when the discomfort threshold UCL is not estimated for only one of the frequencies that need to be measured, the following method may be employed. That is, in step S1010, the frequency setting unit 111 determines two frequencies by adding a frequency that requires measurement and a frequency that has a certain difference from the frequency, for example, a frequency that has a difference of 1000 Hz or more. In step S1015, the sound pressure setting unit 112 sets a sound pressure range for the frequency that needs to be measured, as in step S1015 of the first embodiment. For the test sound having a frequency different from the frequency that needs to be measured and added in step S1010, a sound pressure that is 10 dB or more smaller than the estimated test discomfort threshold UCL that is closest to the set frequency is set. .

  For example, when the frequency that needs to be measured is 1000 Hz, an inspection sound of 2500 Hz is added. At this time, if it is estimated that the unpleasant threshold value UCL at 2000 Hz is 95 dBSPL, a sound pressure of 85 dBSPL or less is set as the sound pressure range for the added 2500 Hz inspection sound. The inspection sound of the frequency that needs to be measured in step S1020 is set in the same manner as in the first embodiment, and one or more sound pressures are set for the added inspection sound of the frequency, and the inspection sound of the required frequency is set in step S1025. Set the presentation order not to be presented continuously. Thereby, by continuing the inspection sound of the same frequency, the characteristic of N1 can be prevented from changing, and the measurement accuracy can be maintained.

(Modification of Embodiment 1)
FIG. 9 shows a configuration of a hearing aid adjustment system 15 according to a modification of the first embodiment. The hearing aid adjustment system 15 is used for fitting the hearing aid using the estimation result of the discomfort threshold UCL by the hearing test apparatus 10.

  The hearing aid adjustment system 15 includes an HTL acquisition unit 210, a provisional UCL setting unit 220, a hearing aid characteristic setting unit 230, and a hearing aid 250 in addition to the configuration of the auditory measurement device 10 (FIG. 1) of the first embodiment described above. Configured. The inspection sound output unit 240 has a different function from the inspection sound output unit 140 shown in FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The HTL acquisition unit 210 receives the hearing ability at each frequency of the subject 100, that is, the minimum audible level (HTL), measured separately. The HTL acquisition unit 210 may be configured with, for example, a numeric keypad and a cursor key. For example, the user selects a frequency with a cursor key, and inputs the minimum audible value HTL of the selected frequency using a numeric keypad. The minimum audible value HTL is the smallest volume of sound that the person can hear and is measured as a hearing test. Further, the HTL acquisition unit 210 may receive the hearing at each frequency of the subject 100 via a communication unit from an audiometer that is a measuring device of the minimum audible value.

  The temporary UCL setting unit 220 sets a temporary discomfort threshold (temporary UCL) from the minimum audible value HTL received by the HTL acquisition unit 210.

  The hearing aid characteristic setting unit 230 inputs the hearing aid from the minimum audible value HTL of the subject 100 of each frequency input from the HTL acquisition unit 210 and the unpleasant threshold UCL of the subject 100 of each frequency estimated by the UCL estimation unit 200. Set the output characteristics. For example, the hearing aid characteristic setting unit 230 includes a CPU, a memory, and a communication interface that communicates with the hearing aid 250. The hearing aid characteristic setting unit 230 transmits adjustment parameters for realizing the input / output characteristics of the set hearing aid to the hearing aid 250 via the communication unit, and writes the parameters to the hearing aid 250.

  The inspection sound output unit 240 includes an amplifier (not shown) having a variable gain. The inspection sound output unit 240 receives the inspection sound signal generated by the inspection sound signal generation unit 130, amplifies it by an amplifier, and outputs it.

  The hearing aid 250 is a programmable hearing aid or a digital hearing aid that is attached to the subject 100 and whose input / output characteristics can be adjusted from the outside. The input / output characteristics of the hearing aid 250 are changed by the hearing aid characteristic setting unit 230.

  Hereinafter, the operation of the above-described hearing aid adjustment system 15 will be described with reference to FIGS. 10 and 11. FIG. 10 schematically shows a method for setting the sound pressure range of the inspection sound according to the modification of the first embodiment. FIG. 11 is a flowchart showing a procedure of processing performed in the hearing aid adjustment system 15.

  In the hearing aid adjustment system 15 of the modified example of the first embodiment, the “user” refers to a person who adjusts the hearing aid worn by the subject 100 according to the auditory state of the subject 100. First, the user inputs the minimum audible value HTL for each frequency of the subject 100 measured separately from the HTL acquisition unit 210. The frequency for inputting the minimum audible value HTL is, for example, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, or 4000 Hz. The white circle in FIG. 10 is the minimum audible value HTL of the subject 100 input from the HTL acquisition unit 210. In FIG. 10, the minimum audible value HTL of the subject is 20 dBSPL at 250 Hz, 15 dBSPL at 500 Hz, 15 dBSPL at 1000 Hz, 25 dBSPL at 2000 Hz, and 25 dBSPL at 4000 Hz.

  First, referring to FIG. Steps S1000 to S1070 in FIG. 11 are processes performed by the auditory measurement device 10, and are the same as the processes shown in FIG. Details of these steps are as described above in connection with the first embodiment. Hereinafter, differences will be mainly described, and other common processing will be briefly described.

  When the input of the minimum audible value HTL ends, the temporary UCL setting unit 220 sets a temporary discomfort threshold (temporary UCL) from the minimum audible value HTL for each frequency at which the HTL is input. For example, the provisional discomfort threshold is set based on a provisional discomfort threshold determined in correspondence with the minimum audible value HTL. FIG. 12 shows an example of a discomfort threshold that is provisionally set according to the HTL range. In the example of FIG. 10, the discomfort threshold is set to 100 dBSPL at 250 Hz, 500 Hz, and 1000 Hz when the minimum audible value HTL is input, and is set to 110 dBSPL at 2000 Hz and 4000 Hz.

  When the hearing test apparatus 10 starts operating, the test sound range determination unit 110 receives a measurement instruction input and starts measurement (S1000). The inspection sound range determination unit 110 of the inspection sound range determination unit 110 sets the frequency of the inspection sound (S1010) and sets the width of the sound pressure (S1015). A method for setting the inspection sound frequency and the sound pressure width will be described later.

  The presentation order determination unit 120 sets test sounds having a plurality of types of sound pressures within the specified sound pressure range at each frequency specified as the test sound (S1020). The total number of test sounds set is 20 when the evoked potentials are extracted by averaging. The total number of stimuli including this repetitive sound satisfies the condition that the same frequency does not continue and is random The order of presenting the inspection sounds is determined by assigning a proper order (S1025).

  The inspection sound signal generation unit 130 generates the inspection sound signal set in step S1020. The inspection sound signal generation unit 130 generates a sine wave as a digital signal. The test sound having the maximum sound pressure among the test sounds set in step S1020 is set as a signal having the maximum amplitude, and the test sounds having other sound pressures are adjusted in amplitude from the maximum amplitude signal according to the relative value of the sound pressure.

  For example, the amplitude value is from −32767 to 0 to +32767 as a 16-bit full-scale acoustic signal. When a sine wave having a maximum sine wave value of 32767 and a minimum value of −32767 is used as a signal equivalent to 70 dBSPL, the 64 dBSPL signal has a half of the signal equivalent to 70 dBSPL. The inspection sound output unit 240 sets the amplification factor of the amplifier at the time of output so that the 16-bit full scale signal becomes the inspection sound having the maximum sound pressure among the inspection sounds set in step S1020 (for example, 70 dBSPL). decide. As a result, it is possible to set a state in which less noise is mixed for each set sound pressure range and output the inspection sound.

  Here, it has been described that the inspection sound having the maximum sound pressure among the inspection sounds set in step S1020 is made to correspond to the full scale. However, when a full-scale signal is input, the inspection sound output unit 240 may determine the amplification factor so that the sound pressure at the upper limit of the sound pressure range set in step S1010 is output. At this time, the inspection sound generation unit 240 may determine the amplitude based on the relative value of the sound pressure of each inspection sound set in step S1020 with respect to the upper limit of the sound pressure width set in step S1010. .

  The test sound output unit 140 sequentially outputs test sounds according to the order of presentation set in step S1025 and presents them to the subject 100. The electroencephalogram measurement unit 150 measures an electroencephalogram from an electrode attached to the skin of the subject 100 (S1030).

  After the electroencephalogram is measured in step S1030, the evoked potential extraction unit 160 adds and averages the electroencephalogram measured for each type of test sound, and extracts the evoked potential (S1040).

  The N1 determination unit 170 extracts an N1 component that is an auditory evoked potential from the evoked potential for each type of inspection sound generated in step S1040 (S1050). The extraction of the N1 component is performed by obtaining the maximum negative value between 80 ms and 200 ms, with the test sound presentation start time being 0. The latency calculation unit 180 expresses the point indicating the obtained negative maximum value as a position on the time axis with the test sound presentation start time set to 0, and sets it as the latency of N1.

  The UCL estimation unit 200 compares the latency of N1 extracted in step S1050 for each frequency of the inspection sound, and determines whether or not the latency reduction width corresponding to the increase in the sound pressure of the inspection sound has been reduced by a certain amount or more. to decide. Furthermore, the UCL estimation unit 200 determines whether or not sound pressures that reduce the latency reduction width by a certain value or more have been determined for all frequencies of the inspection sound (S1060).

  Of the frequencies to be measured, if there remains a frequency at which the sound pressure at which the N1 latency shortening range with respect to the increase in sound pressure is not determined, that is, No in step S1060, the process proceeds to step S1015 via step S1065. Return. If the sound pressure at which the reduction width of the N1 latency with respect to the increase in sound pressure is reduced is determined for all the inspection sound frequencies, that is, if Yes in step S1060, the process proceeds to the next step.

  The UCL estimation unit 200 refers to the intensity latency relationship storage unit 190 and estimates the unpleasant threshold value UCL (S1070). The UCL estimation unit 200 refers to the intensity latency relation storage unit 190 based on the sound pressure extracted for each test sound and the reduction range of the N1 latency reduction time and the latency reduction time per 10 dB increase in sound pressure. Then, an additional value used for estimation of the unpleasant threshold value UCL is obtained, and the respective additional values are added to the sound pressure at which the shortening range of the N1 latency with respect to the increase in the sound pressure is reduced. Is estimated.

  The hearing aid characteristic setting unit 230 determines the input / output characteristics of the hearing aid 250 from the unpleasant threshold value UCL and the minimum audible value HTL output from the UCL estimation unit 200 (S1090). An example of the procedure for determining the input / output characteristics is shown below. First, at each frequency, when there is an input of 10 dBSPL, a setting is made to output an amount of the minimum audible value HTL. For example, in the example of FIG. 10, the 10 dBSPL input at 250 Hz is set to 20 dBSPL output at 250 Hz, and the 10 dBPL input is set to 15 dBSPL at 500 Hz. The same applies to other frequencies. Further, the input / output characteristics are set so that an input of 100 dBSPL or more of each frequency is output at the sound pressure of the unpleasant threshold value UCL estimated in S1070.

  The hearing aid characteristic setting unit 230 outputs the set input / output characteristics to the hearing aid 250 as input / output characteristic data of the hearing aid 250 (S1100). The hearing aid 250 records the data received from the hearing aid characteristic setting unit 230 and completes the setting of the input / output characteristics. Thereby, the adjustment of the hearing aid 250 ends.

  FIG. 13 is a graph of an example of measurement results in the modification of the first embodiment.

  It can be said that the inspection sound range determination unit 110 sets the sound pressure range of the inspection sound by satisfying a predetermined condition at the frequency at which the discomfort threshold is to be measured. The predetermined conditions are the following conditions 1) to 3). That is, 1) It is within the range of the sound pressure smaller than the assumed discomfort threshold UCL. 2) The measurement results can be acquired with at least three types of sound pressures in a series of measurements including multiple sound pressure range settings. 3) When the sound pressure range is set a plurality of times, the sound pressure range is set within a sound pressure range larger than the sound pressure range set in the preceding sound pressure range setting.

  In the example of FIG. 7 of the first embodiment, the uncomfortable threshold UCL for a normal hearing person is about 100 dBSPL, and thus the sound pressure range is set with an assumed uncomfortable threshold UCL set to 100 dBSPL. On the other hand, in the example of FIG. 10 of this modification, the discomfort threshold UCL is assumed from the HTL based on the table of FIG. Therefore, based on the condition of 1), the sound pressure range of the inspection sound is set in a range not exceeding 100 dBSPL for 250 Hz, 500 Hz, and 1000 Hz and not exceeding 110 dBSPL for 2000 Hz and 4000 Hz.

  First, as the initial sound pressure range setting, a range from 70 dBSPL to 90 dBSPL is set for each frequency according to the conditions of 1) to 3). According to the sound pressure range of the inspection sound, for example, output sound pressures of 70 dBSPL, 80 dBSPL, and 90 dBSPL are determined for each of the five frequencies in step S1020, and 15 types of inspection sound are set. Furthermore, repeated measurement for 20 averages is set for each of 15 types of test sounds, and 300 test sound presentations are set for the setting of the frequency and sound pressure range of the first test sound.

  N1 latencies for 15 types of test sounds are determined for the setting of the frequency and sound pressure range of the first test sound. In step S <b> 1060, the UCL estimation unit 200 compares the latency reduction width corresponding to the increase in sound pressure at each frequency. For example, when the N1 latency as shown in FIG. 13 is obtained, 90 dBSPL is regarded as a sound pressure with a reduced width of the N1 latency reduced at 500 Hz and 1000 Hz. At 250 Hz, 2000 Hz, and 4000 Hz, it is not possible to determine the sound pressure with the reduced width of the N1 latency.

 In the setting of the frequency and sound pressure range of the second inspection sound, 250 Hz, 2000 Hz, and 4000 Hz are set, in which the sound pressure in which the reduction width of the N1 latency is reduced at the first time is not determined. Regarding the sound pressure, the assumed discomfort threshold UCL is 100 dBSPL according to the conditions of 1) to 3). Therefore, a range from 91 dBSPL to 99 dBSPL is set for 250 Hz. Since the assumed UCL is 110 dBSPL at 2000 Hz and 4000 Hz, a range from 91 dBSPL to 100 dBSPL is set. For 250 Hz, the sound pressure of the inspection sound is 95 dBSPL and 99 dBSPL, and for 2000 Hz and 4000 Hz, the sound pressure of the inspection sound is 95 dBSPL and 100 dBSPL. Two types of sound pressures are set for each frequency, and 120 test sound presentations including 20 repetitions of 6 types of test sounds are set.

  Similar to the first time, the latency of N1 for six types of inspection sounds is obtained. As shown in FIG. 13, at 250 Hz, the N1 latency for both 95 dBSPL and 99 dBSPL is 98 ms, and the sound pressure with the reduced N1 latency is determined to be 95 dBSPL. At 2000 Hz, the N1 latency for the 95 dBSPL test sound is 102 ms and for 100 dBSPL it is 100 ms. At 4000 Hz, the N1 latency for the 9dDBSPL inspection sound is 103 ms and for 100 dBSPL it is 101 ms. For both 2000 Hz and 4000 Hz, the decrease in latency with respect to an increase in sound pressure from 95 dBSPL to 100 dBPL is reduced by more than 20% from the decrease in latency with respect to an increase in sound pressure from 90 dBSPL to 95 dBSPL, and the reduction in N1 latency is reduced. The sound pressure is determined to be 100 dBSPL.

  In the second measurement, the sound pressure in which the reduction width of the N1 latency is reduced at all frequencies is determined. In the case of Yes in S1060, the UCL estimation unit 200 is stored in the intensity latency relationship storage unit 190 in S1070. Based on the relationship of 4, the discomfort threshold value UCL of each frequency is estimated. For 500 Hz and 1000 Hz, the added value 5 dB corresponding to the latency reduction width 3 ms is added to 90 dBSPL, the unpleasant threshold UCL is set to 95 dBSPL, and for 250 Hz, the addition value 4 dB corresponding to the latency reduction width 2 ms per 10 dB is set to 95 dBSPL. In addition, the discomfort threshold UCL is set to 99 dBSPL. For 2000 Hz and 4000 Hz, the added value 6 dB corresponding to the latency reduction width of 4 ms per 10 dB is added to 100 dBSPL, and the discomfort threshold UCL is set to 106 dBSPL.

  According to the hearing aid adjustment system 15 configured as described above, the discomfort threshold UCL necessary for determining the input / output characteristics of the hearing aid by the test sound having the sound pressure equal to or lower than the discomfort threshold UCL is set to a level uncomfortable for the subject. The determination can be made without compelling to listen to the test sound, and the burden on the subject, that is, the user of the hearing aid can be reduced.

(Embodiment 2)
FIG. 14 is a configuration diagram of the auditory test apparatus 20 according to the second embodiment. In the present embodiment, a process for estimating a comfort range including a discomfort threshold value (UCL) and a comfort value (MCL) using the N1-P2 amplitude will be described.

  According to the configuration shown in FIG. 14, in the auditory test apparatus 20, the N1 determination unit 170 of the auditory test apparatus 10 shown in FIG. 1 can be replaced with the N1-P2 extraction unit 370, and the latency calculation unit 180 is replaced with the amplitude calculation unit. 380 has been replaced. Further, the intensity latency relationship storage unit 190 is replaced with an intensity amplitude relationship storage unit 390, and the UCL estimation unit 200 is replaced with a comfort range estimation unit 400. Other than that, the configuration of the auditory test apparatus 20 is the same as the configuration of the auditory test apparatus 10. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted as appropriate.

  The auditory inspection device 20 of the present embodiment includes an inspection sound range determination unit 110, a presentation order determination unit 120, an inspection sound signal generation unit 130, an inspection sound output unit 140, an electroencephalogram measurement unit 150, and a calculation unit 310. The intensity amplitude relationship storage unit 390 and the comfort range estimation unit 400 are provided.

  The calculation unit 310 includes an evoked potential extraction unit 160, an N1-P2 extraction unit 370, and an amplitude calculation unit 380.

  Among these, the N1-P2 extraction unit 370 extracts N1 which is a negative potential with a latency of about 100 ms and P2 which is a positive potential following N1 from the evoked potentials extracted by the evoked potential extraction unit 160.

  The amplitude calculator 380 measures the absolute value of the potential difference between the N1 maximum amplitude point extracted by the N1-P2 extraction unit 370 and the P2 maximum amplitude point.

  The intensity amplitude relationship storage unit 390 stores a correspondence relationship between the perceptual sound volume and the N1-P2 amplitude.

  The comfortable range estimation unit 400 comfortably listens to the pure tone from the amplitude measured by the amplitude calculation unit 380 based on the correspondence relationship between the loudness stored in the intensity amplitude relationship storage unit 390 and the N1-P2 amplitude. A comfortable range that is a range of sound pressure that can be detected is determined, and a discomfort threshold UCL is estimated.

  The inspection sound range determination unit 110, the presentation order determination unit 120, the inspection sound signal generation unit 130, the evoked potential extraction unit 1690, the N1-P2 extraction unit 370, the amplitude calculation unit 380, and the comfort range estimation unit 400 are, for example, one or more. This is realized by a computer and a memory. The intensity amplitude relationship storage unit 390 is realized by one or a plurality of memories.

  Prior to detailed description of the present embodiment, characteristics of the N1-P2 amplitude will be described.

 As already explained, N1-P2 is a series of evoked potentials evoked by auditory stimulation, N1 is a negative potential with a latency of about 100 ms, and P2 is a positive component with a latency of about 200 ms following N1. The N1-P2 amplitude indicates the absolute value of the potential difference between the point where N1 has the maximum amplitude and the point where P2 has the maximum amplitude. FIGS. 15A to 15C show examples of waveforms of the measurement results of N1-P2. FIG. 15A shows the N1-P2 waveform when the presentation sound pressure is 90 dBSPL, FIG. 15B shows the N1-P2 waveform when the presentation sound pressure is 70 dBSPL, and FIG. 15C shows the case where the presentation sound pressure is 60 dBSPL. N1-P2 waveform. In each of FIGS. 15A, 15B, and 15C, the vertical axis represents potential and the unit is μV. Since the evoked potential often displays a negative potential upward, the vertical axis in FIG. 15 also displays a negative potential upward. The horizontal axis is time, and the unit is ms. The zero point on the horizontal axis is the stimulus sound presentation start time.

  As shown in FIG. 15A, the N1-P2 amplitude indicates the amplitude of the potential from a negative peak of about 100 ms to a positive peak of about 200 ms. Therefore, the N1-P2 amplitude is the absolute value of the difference (negative) between the peak potential (negative) of N1 and the peak potential (positive) of P2, in other words, the absolute value of the peak potential (negative) of N1 and the value of P2. Calculated as the sum of the peak potential (positive). The N1-P2 amplitude becomes smaller as the sound pressure of the stimulation sound becomes smaller, and it becomes difficult to specify each component. N1 appears to appear at about 10 dB above the threshold value, but when automatically determining the presence or absence of a component, it is necessary to determine at about 20 dB to 30 dB above the threshold value.

  The method for determining the presence or absence of the N1 component by the amplitude calculator 380 is as follows. First, the amplitude calculator 380 extracts the maximum value of the negative amplitude between 80 ms and 200 ms, with the auditory stimulus presentation time point being 0 (starting point). This value corresponds to the peak potential of N1. Next, the amplitude calculator 380 extracts the maximum value of the positive amplitude in the time interval of 200 ms from the time position of the negative amplitude maximum value. This value corresponds to the peak potential of P2. The potential difference between the negative amplitude maximum value and the positive amplitude maximum value is defined as N1-P2 amplitude. When this amplitude is smaller than a predetermined threshold, for example, 7 μV, it is considered that the components of N1 and P2 cannot be specified.

  In addition to the above method, a typical waveform of N1-P2 is stored as a waveform template, and if the correlation coefficient with this waveform template is smaller than a predetermined threshold, it is considered that the components of N1 and P2 cannot be specified. May be. Also, using discriminant analysis such as linear discriminant, the data when N1 and P2 do not exist are used as teacher data, and if it is determined that the data is close to the teacher data, the components of N1 and P2 cannot be specified. Also good. The lower limit of the comfortable range is, for example, a value that is 10 dB larger than the sound pressure that can identify the N1 and P2 components.

  As indicated by the solid line in FIG. 3, the N1-P2 amplitude increases as the perceptual magnitude of the sound increases. When the sound energy is expressed logarithmically, the N1-P2 amplitude increases almost linearly between about 20 dB and about 70 dB above the threshold. In FIG. 3, the amplitude increases relatively linearly from 10 dBSL to 80 dBSL, but the increase of the N1-P2 amplitude is small at 80 dBSL and 90 dBSL.

  The inventors of the present application assume that the range in which the linearity of the correspondence relationship between the sound volume and the N1-P2 amplitude is maintained is a comfortable range, and that there is a discomfort threshold UCL in a range of large sound pressures that deviates from the comfortable range. .

  Based on the N1-P2 amplitude characteristic and the comfort range (linearity) recognition criteria as described above, the comfort range estimation unit 400 uses the N1-P2 amplitude measured by the amplitude calculation unit 380 to increase the sound pressure of the test sound. Obtain the amplitude increase. And the comfortable range estimation part 400 compares the increase width of N1-P2 amplitude in the adjacent sound pressure increase width, and when the amplitude increase width becomes small, for example, 30% or more, it is considered that the linearity has collapsed.

  The intensity-amplitude relationship storage unit 390 stores, for example, the relationship between the amount of increase in amplitude at the sound pressure at which the decrease in amplitude increase width is detected and the difference in sound pressure from the decrease in amplitude increase width to the unpleasant threshold UCL. . FIG. 16 is an example of a table indicating the relationship between the amplitude, the comfort range, and the discomfort threshold UCL stored in the intensity amplitude relationship storage unit 390. In the present embodiment, the intensity amplitude relationship storage unit 390 increases the amount of amplitude with respect to a sound pressure increase of 10 dB, an added value for calculating a comfortable range, and an added value for estimating the unpleasant threshold UCL (UCL estimation). Memorize the correspondence. In the present embodiment, the comfort range estimation unit 400 extracts a test sound in which the amplitude increase width decreases, and based on the correspondence stored in the intensity amplitude relationship storage unit 390 based on the sound pressure of the test sound, The upper limit of the range is calculated, and an estimated value of the discomfort threshold UCL is obtained.

  According to the graph shown in FIG. 3, when the sound pressure increases by 10 dB between 30 dBSL and 80 dBSL, the amplitude of 1 μV increases. For an increase in sound pressure from 80 dBSL to 90 dBSL, the amplitude increases by 0.2 μV. The sound pressure at which linearity is lost is 80 dBSL, and the amount of increase in amplitude per 10 dB of sound pressure increase at this sound pressure is greater than 0 and less than or equal to 0.3 μV in the table of FIG. Considering these, the upper limit of the comfort range is estimated to be 75 dBSL, and the estimated value of the unpleasant threshold UCL is estimated to be 90 dBSL.

  Next, the operation of the hearing test apparatus 20 configured as described above will be described with reference to FIGS. 17 and 18.

  FIG. 17 is a flowchart showing a processing procedure of the hearing test apparatus 20 according to the present embodiment. The same processes as those in the flowchart shown in FIG.

  First, when the hearing test apparatus 20 starts operating, first, the test sound range determination unit 110 receives input of measurement instruction information and starts measurement (S1000).

  The inspection sound range determination unit 110 sets a plurality of inspection sound frequencies (S3010), and then sets the width of the sound pressure of the inspection sound (S3015). A method for setting the inspection sound frequency and the sound pressure width will be described later.

  With the input of a plurality of inspection sound frequencies and sound pressure ranges set by the inspection sound range determination unit 110, the presentation order determination unit 120 sets a plurality of frequencies within the specified sound pressure range at each frequency specified as the inspection sound. Are set as the presenting sound pressure of the inspection sound (S3020). The total number of test sounds set is 20 when the evoked potentials are extracted by averaging. The total number of stimuli including this repetitive sound satisfies the condition that the same frequency does not continue and is random The order of presenting the inspection sounds is determined by assigning a proper order (S3025).

  Next, the inspection sound set in step S3020 is generated by the inspection sound signal generation unit 130, the inspection sounds are sequentially output from the inspection sound output unit 140 in accordance with the presentation order set in step S3025, and presented to the subject 100. An electroencephalogram is measured from the electrode worn on the scalp of the subject 100 by the electroencephalogram measurement unit 150 (S1030).

  After measuring the electroencephalogram in S1030, the evoked potential extraction unit 160 extracts the evoked potential for each type of test sound (S1040). The type of inspection sound is a type based on the frequency and sound pressure of the inspection sound determined in step S3010.

  The N1-P2 extraction unit 370 extracts N1 and P2 components that are auditory evoked potentials from the evoked potentials for each type of test sound generated in step S1040 (S3050). The N1 component and P2 component extraction method is as described above.

  The amplitude calculator 380 calculates the potential difference between both components N1 and P2 extracted in step S3050, and obtains the N1-P2 amplitude (S3060).

  The comfort range estimation unit 400 compares the N1-P2 amplitude calculated in step S3060 for each frequency of the test sound, and whether or not the amplitude increase corresponding to the increase in the sound pressure of the test sound has decreased by a certain level or not. Determine. Furthermore, the comfort range estimation unit 400 determines whether or not the sound pressure at which the increase amount of the N1-P2 amplitude with respect to the increase in sound pressure is reduced is determined for all the frequencies set in step S3010 (S3070).

  Whether or not the amount of increase in amplitude has decreased by a certain value or more is determined as follows. That is, the comfort range estimation unit 400 obtains the amount of increase in amplitude per 10 dB of sound pressure increase for the N1-P2 amplitude corresponding to each presented sound pressure at a specific frequency. For example, in the calculation section of the amplitude increase amount created by the presentation sound pressure of each stimulation sound, the comfort range estimation unit 400 compares the amplitude of the section where the sound pressure is higher than the amplitude increase amount of the section where the sound pressure is lower. When the increase amount is smaller than 30%, that is, when the increase amount in the section where the sound pressure is high is less than 70% of the increase amount in the section where the sound pressure is low, it is considered that the increase amount of the amplitude is small.

  When the comfort range estimation unit 400 determines that the inspection sound frequency for which the sound pressure at which the increase in the N1-P2 amplitude with respect to the increase in the sound pressure is reduced is not determined, that is, in the case of No in step S3070, The process proceeds to step S1065. In step S1065, the frequency setting unit 111 sets an uninspected frequency among the frequencies of the inspection sound determined in step S3010. Then, the same process is performed again from step S3015.

  When the comfortable range estimation unit 400 determines that the sound pressure that reduces the increase amount of the N1-P2 amplitude with respect to the increase in sound pressure is determined for all the inspection sound frequencies, the process proceeds to “Yes” in step S3070.

  The comfort range estimation unit 400 refers to the intensity amplitude relationship storage unit 390, obtains the upper limit of the comfort range, and estimates the discomfort threshold UCL (S3080). The comfort range estimation unit 400 refers to the intensity amplitude relationship storage unit 390 based on the sound pressure at which the increase amount of the N1-P2 amplitude extracted for each test sound decreases and the increase amount of the amplitude per 10 dB increase in sound pressure at that time. Thus, an addition value used for calculating the upper limit of the comfort range and an addition value used for estimating the unpleasant threshold value UCL are obtained. By adding each added value to the sound pressure in which the increase amount of the N1-P2 amplitude with respect to the increase in sound pressure is reduced, the upper limit of the comfortable range for each frequency of the subject 100 is obtained, and the discomfort threshold UCL is estimated. Further, when the minimum sound pressure capable of specifying the N1-P2 component is recorded, a value obtained by adding 10 dB to the minimum sound pressure specifying the N1-P2 component is set as the lower limit of the comfortable range. When the N1-P2 component is specified in all of the inspection sounds of the specific frequency, the lower limit of the comfortable range is set to the lower limit of the comfortable range of the normal hearing person. For example, 30 dB.

  The comfort range estimation unit 400 outputs the upper and lower limits of the comfort range for each frequency and the discomfort threshold UCL obtained in step S3080 as measurement results and estimation results. The comfort range estimation unit 400 outputs the result to a display device such as a display, for example, displays the comfort range and the discomfort threshold UCL for each frequency of the test sound (S3090), and ends the process.

  The inspection sound range determination unit 110 sets the sound pressure range of the inspection sound that satisfies the three conditions described in the first embodiment at the frequency at which the comfort range is to be measured. Unlike Embodiment 1, in this embodiment, in order to obtain the lower limit of the comfort range, the sound pressure range is set with the lower limit of the comfort range of the normal hearing person, for example, 30 dBSPL as the lower limit of the sound pressure range setting.

  FIG. 18 schematically illustrates an example of a process in which the inspection sound range determination unit 110 sets the frequency of the inspection sound and the width of the sound pressure. FIG. 19 is a graph showing an example of the measurement result of the N1-P2 amplitude in the example of FIG.

  The details of the operation of the inspection sound range determination unit 110 in step S3010 of FIG. 17 will be described below with reference to FIGS.

  In the example of FIG. 18, the frequencies to be measured are 500 Hz, 1000 Hz, and 2000 Hz. At these frequencies, the lower limit of the comfort range of the normal hearing person is about 30 dBSPL, and the unpleasant threshold UCL is about 100 dBSPL. Therefore, as the initial sound pressure range setting, first, the comfortable range of the normal hearing person is set for each frequency. Is set in a sound pressure range smaller than 100 dBSPL according to the condition of 1).

  In the example of FIG. 18, the initial sound pressure setting is performed by setting a range of sound pressure levels (vertical axis) from 30 dBSPL to 70 dBSPL for each frequency as indicated by white arrows. According to the sound pressure range of the inspection sound, for example, output sound pressures of 30 dBSPL, 50 dBSPL, and 70 dBSPL are determined for each of the three frequencies in step S3020, and nine types of inspection sound are set. Furthermore, for each of the nine types of inspection sounds, a sufficient number of additions, for example, 20 repeated averages are set for repeated averaging, and a total of 180 inspections are performed for the setting of the frequency and sound pressure range of the initial inspection sound. Sound presentation is set.

  N1-P2 amplitudes for nine types of inspection sounds are obtained in steps S1030, S1040, and S3050 with respect to the frequency and sound pressure range of the inspection sound set for the first time. In FIG. 19, N1-P2 components could be identified at 500 Hz and 1000 Hz even at 30 dBSPL, but at 2000 Hz, N1-P2 components were not observed in the evoked potential for 30 dBSPL. In step S3060, the amplitude calculator 380 calculates the N1-P2 amplitude only for the evoked potential for which the N1-P2 component could be specified in step S3050. The comfortable range estimation unit 400 compares the amount of increase in the N1-P2 amplitude corresponding to the increase in sound pressure at each frequency. For example, when N1-P2 amplitude as shown in FIG. 19 is obtained for the first 30 dBSPL, 50 dBSPL, and 70 dBSPL test sounds, the amplitude increases by 1.7 μV with respect to the sound pressure increase from 30 dBPL to 50 dBSPL at 500 Hz. The increase in sound pressure from 50 dBSPL to 70 dBSPL was 2.2 μV. Since the component of N1-P2 can be specified at 30 dB, the lower limit of the comfortable range is determined to be 30 dBSPL, which is the same as that of a normal hearing person. Since the amplitude increase amount from 50 dBSPL to 70 dBSPL is larger than the amplitude increase amount from 30 dBSPL to 50 dBSPL, the sound pressure at which the increase amount decreases is not specified from the initial test sound range. The same applies to 1000 Hz. For 2000 Hz, the N1-P2 component is not specified in 30 dBSPL, and therefore the increase in N1-P2 amplitude between 50 dBSPL and 70 dBSPL can be measured, but the increase cannot be compared.

  However, since N1-P2 is specified by 50 dBSPL, 10 dB is added to 50 dBSPL, and 60 dBSPL is set as the lower limit of the comfortable range. In the sound pressure range of the first inspection sound, since the sound pressure at which the increase in N1-P2 amplitude with respect to the increase in sound pressure is reduced at each frequency of the inspection sound is not determined, the result is No in step S3070, and after step S1065. Returning to S3015, the second frequency is set.

  At the first time, since the sound pressure at which the increase amount of the amplitude of N1-P2 is reduced has not been determined at 500 Hz, 1000 Hz, and 2000 Hz, the frequency of the second inspection sound is the same as that of the first time (S1065). According to the condition of 1), the sound pressure range is set to a sound pressure range smaller than 100 dBSPL. According to the condition 2), the sound pressure range is set so that three or more types of sound pressure can be set including the first inspection sound. According to the condition 3), the first sound pressure range is set in the range of 30 dBSPL to 70 dBSPL. In the example of FIG. 18, a range from 71 dBSPL to 90 dBSPL is set based on the above conditions (S3015).

 According to the sound pressure range of the inspection sound and the interval between the maximum sound pressure of the inspection sound and the sound pressure of the inspection sound set for the first time, the sound pressure of the inspection sound is determined for each of the three types of frequencies in step S3020. In the examples of FIGS. 18 and 19, the maximum sound pressure of the first test sound is 70 dB, and the sound pressure interval is 20 dB. At 2000 Hz, the sound pressure at which the N1-P2 component can be specified is only two points, 50 dBSPL and 70 dBSPL, so two or more kinds of sound pressure settings are required. In the example of FIGS. 18 and 19, for example, 20 dB from 70 dBSPL to 90 dBSPL is set to a 10 dB interval, and two types of 80 dBSPL and 90 dBSPL are set.

 Similar to the first time, by the operations from step S1030 to step S3050, the N1-P2 extraction unit 370 extracts the N1 component and the P2 component, and the amplitude calculation unit 380 obtains N1-P2 amplitudes for the six types of inspection sounds. As shown in FIG. 19, at 500 Hz, the voltage is 11 μV for 80 dBSPL and 11.8 μV for 90 dBSPL. In addition to the N1-P2 amplitude measured for the first time, the increase in amplitude from 70 dBSPL to 80 dBSPL is 0.9 μV per 10 dB, the increase in amplitude from 80 dBSPL to 90 dBSPL is 0.8 μV per 10 dB, and the increase in amplitude from 70 dBSPL to 80 dBSPL Since it corresponds to 88% of the amount, the sound pressure at which the increase amount of the N1-P2 amplitude is reduced is not determined in the sound pressure range of the first and second inspection sounds. For 1000 Hz, it is 11.9 μV for 80 dBSPL and 12.6 μV for 90 dBSPL. An amplitude increase from 80 dBSPL to 90 dBSPL is 0.7 μV per 10 dB, which is 64% of an amplitude increase of 1.1 μV from 70 dBSPL to 80 dBSPL. Therefore, 80 dBSPL is determined as the sound pressure at which the increase amount of the N1-P2 amplitude is reduced. For 2000 Hz, the N1-P2 amplitude for 80 dBSPL is 10.9 μV, the N1-P2 amplitude for 90 dBSPL is 11.7 μV, and the amplitude increase from 80 dBSPL to 90 dBSPL is 0.8 μV. This is 62% of an amplitude increase of 1.3 μV from 70 dBSPL to 80 dBSPL. Therefore, similarly to 1000 Hz, 80 dBSPL is determined as the sound pressure at which the increase amount of the N1-P2 amplitude is reduced.

  In the second measurement, the comfort range estimation unit 400 determines the sound pressure at which the increase amount of the N1-P2 amplitude is reduced for 1000 Hz and 2000 Hz among the three frequencies. For 500 Hz, since the sound pressure at which the increase amount of the N1-P2 amplitude is reduced is not determined, the result of step S3070 is No, and the process returns to step S3010.

  In the second measurement, since the sound pressure at which the increase amount of the N1-P2 amplitude at 1000 Hz and 2000 Hz is reduced is determined, 500 Hz is set as the frequency of the third test sound (S1065). In the setting of the sound pressure range, the sound pressure range is set according to the following three conditions for 500 Hz where the sound pressure at which the increase amount of the N1-P2 amplitude is reduced is not determined. According to the condition of 1), a sound pressure range up to 100 dBSPL is set. According to the condition 2), a sound pressure width of 2 dB or more is set. According to the condition 3), a sound pressure range greater than 90 dBSPL is set.

  In the example of FIG. 18, the third sound pressure setting is performed by setting a range from 91 dBSPL to 95 dBSPL as indicated by the third arrow at a position where the sound pressure is highest at a frequency of 500 Hz. In step S3020, the sound pressure of the test sound is determined, but the maximum sound pressure is 90 dBSPL among the test sounds when the second sound pressure is set, and there are two or more types of sound pressures up to the second sound pressure range setting. Since the N1-P2 amplitude is measured, only 95 dBSPL needs to be measured in order to satisfy the sound pressure condition. However, one type of inspection sound is a good condition for recording the N1 component. Absent. It is necessary to maintain the amplitude of the N1 component by not presenting the stimulus to be presented to the subject 100 by presenting a plurality of types of inspection sounds at random. Therefore, the presentation order determining unit 120 divides the 5 dB section from 90 dBSPL to 95 dBSPL into 3 dB and 2 dB, and prepares two types of inspection sounds of 93 dBSPL and 95 dBSPL, each of which is repeated 40 times and 40 inspection sounds. Present at random.

  Similarly to the second time, N1-P2 amplitudes for two types of inspection sounds are obtained by the operations from S1030 to S3050. As shown in FIG. 19, the N1-P2 amplitude for the test sound of 93 dBSPL at 500 Hz is 11.9 μV, and the N1-P2 amplitude for the test sound of 95 dBSPL is 12 μV. The increase in amplitude with respect to the increase in sound pressure from 90 dBSPL to 93 dBSPL is 0.3 μV per 10 dB, which is 42% of the increase in amplitude with respect to the increase in sound pressure from 80 dBSPL to 90 dBSPL. Therefore, 90 dBSPL is determined as the sound pressure at which the increase amount of the N1-P2 amplitude is reduced. As a result, the sound pressure at which the increase amount of all N1-P2 amplitudes at 500 Hz, 1000 Hz, and 2000 Hz is reduced is determined, and the result is Yes in step S3070.

  In step S3080, the comfort range estimation unit 400 first sets the lower limit of the comfort range. As described above, in the examples of FIGS. 18 and 19, the lower limit of the comfort range is determined to be 30 dBSPL at 500 Hz and 1000 Hz, and to 60 dBSPL at 2000 Hz. Based on the relationship of FIG. 14 stored in the intensity amplitude relationship storage unit 390, the upper limit of the comfortable range is determined. At 500 Hz, the sound pressure at which the increase amount of the N1-P2 amplitude is reduced is 90 dBSPL, and the increase in amplitude per 10 dB is 0.33 μV, which corresponds to the third row in FIG. The added value 0 dB is added to 90 dBSPL, which is the sound pressure at which the increase amount of the N1-P2 amplitude is reduced, and 90 dBSPL is set as the upper limit of the comfortable range. For 1000 Hz, the increase in amplitude from 80 dBSPL to 90 dBSPL, which is the sound pressure at which the N1-P2 amplitude increase is reduced, is 0.7 μV. Therefore, by adding 3 dB to 80 dBSPL, 83 dBSPL is set as the upper limit of the comfortable range. To do. Similarly, 83 dBSPL is set as the upper limit of the revised range for 2000 Hz. Furthermore, the comfort range estimation unit 400 estimates the discomfort threshold value UCL of each frequency based on the relationship between the N1-P2 amplitude of FIG. 16 stored in the intensity amplitude relationship storage unit 390 and the discomfort threshold value UCL. At 500 Hz, 12 dB is added to 90 dBSPL and 102 dBBSPL, and at 1000 Hz and 2000 Hz, 15 dB is added to 80 dBBSPL to estimate 95 dBSPL.

  In the auditory test apparatus 20 configured as described above, the range of the sound pressure of the test sound presented in an arbitrary order is sequentially increased, and the continuous auditory evoked potential N1 is increased with respect to the increase of the sound pressure of the test sound. And an increase amount of the N1-P2 amplitude which is a difference between the maximum amplitudes of P2 is measured. The sound pressure at which the increase amount of the N1-P2 amplitude decreases is determined, and the comfortable range that is the range of the sound pressure that is easy to hear is determined from the correspondence relationship between the increase amount of the N1-P2 amplitude and the sound pressure. An unpleasant threshold value UCL that is a sound pressure larger than the sound pressure of the sound is estimated. As a result, not only the comfortable range but also the unpleasant threshold value UCL can be determined only by the test sound having a sound pressure equal to or lower than the unpleasant threshold value UCL, and the burden on the subject to listen to an unpleasant loudness test sound can be reduced. it can.

  In the second embodiment, at the time of the third measurement, the frequency of the inspection sound is set to only 500 Hz in step S3010, and the sound pressure of the inspection sound is set to 93 dBSPL in step S3020 in order not to repeat the same inspection sound with the same frequency and sound pressure. Two were 95 dBSPL. However, in step S3010, in addition to 500 Hz, 2000 Hz separated by 1000 Hz or more is added to the inspection sound. In step S3020, the sound pressure of the 500 Hz inspection sound is set to only 95 dBSPL, and the 2000 Hz inspection sound has an upper limit of a comfortable value of 2000 Hz. It may be 70 dBSPL which is 10 dB below the determined 80 dB. In this manner, the order of presentation may be determined and measured so that test sounds having the same frequency are not continuously presented in step S3025. Thereby, the change of the characteristic by the familiarity of N1 can be prevented. Therefore, measurement with higher accuracy is possible than measurement by continuous presentation of test sounds having the same frequency and different sound pressures in the second embodiment.

(Modification of Embodiment 2)
The configuration of the hearing test apparatus according to the modification of the second embodiment is the same as that of the second embodiment. Therefore, the description of the auditory examination apparatus 20 is also used as it is in the description of this modification.

  This modification is the same as Embodiment 2 except that the procedure for determining the inspection sound in step S3020 is different from the procedure for determining the presentation order.

  Hereinafter, the operation of the hearing test apparatus 20 according to the present modification will be described with reference to FIGS. 11 and 18. FIG. 20 is a flowchart showing a procedure of processing performed in the auditory test apparatus 20.

  First, when the hearing test apparatus 10 starts operating, the test sound range determination unit 110 accepts a measurement instruction input and starts measurement (S1000). The inspection sound range determination unit 110 sets the frequency type of the inspection sound and the width of the sound pressure (S3010). Using the frequency type and sound pressure range of the inspection sound set by the inspection sound range determination unit 110 as inputs, the presentation order determination unit 120 has a plurality of types within the specified sound pressure range at each frequency specified as the inspection sound. The inspection sound of the sound pressure is set (S3020). Adjust the number of additions when extracting the evoked potentials by averaging, according to the sound pressure of the set test sound, increase the number of additions to obtain evoked potentials with less error around the upper limit of the comfort range, and other sounds By setting the number of pressures to a smaller number of additions, it is possible to accurately measure the comfort range and the discomfort threshold UCL without extending the measurement time.

  The presentation order determination unit 120 further determines the presentation order of all the inspection sounds including the determined number of additions for each of the determined inspection sounds of each frequency and sound pressure, and the subject cannot predict the repetition of the same inspection sounds. The order is determined (S4020). The procedure for setting the number of additions will be described later.

  Next, the inspection sound signal generation unit 130 generates the inspection sound set in step S4020, sequentially outputs the inspection sound from the inspection sound output unit 140 according to the presentation order set in step S4020, and presents it to the subject 100. An electroencephalogram is measured from the electrode worn on the scalp of the subject 100 by the electroencephalogram measurement unit 150 (S1030).

  After measuring the electroencephalogram in step S1030, the evoked potential extraction unit 160 extracts the evoked potential for each inspection sound of the same type (S1040). At this time, the number of additions differs for each inspection sound.

  The N1-P2 extraction unit 370 extracts N1 and P2 components that are auditory evoked potentials from the evoked potentials generated for each type of test sound generated in step S1040 (S3050). The amplitude calculation unit calculates the potential difference between the N1 and P2 components extracted in step S3050, and obtains the N1-P2 amplitude (S3060).

  The comfort range estimation unit 400 compares the N1-P2 amplitude calculated in step S3060 for each frequency of the test sound, and whether or not the amplitude increase corresponding to the increase in the sound pressure of the test sound has decreased by a certain level or not. Is determined (S3070).

  If there is an inspection sound frequency for which the sound pressure at which the increase amount of the N1-P2 amplitude with respect to the increase in the sound pressure is reduced is not determined, that is, No in step S3070, the process returns to step S3015 via step S1065.

  If the sound pressure at which the increase amount of the N1-P2 amplitude with respect to the increase in the sound pressure is reduced is determined for all the inspection sound frequencies, that is, if Yes in step S3070, the process proceeds to the next step S3080.

  The comfort range estimation unit 400 refers to the sound intensity N1-P2 latency relationship storage unit 390, obtains the upper limit of the comfort range, and estimates the discomfort threshold UCL (S3080). Further, when the minimum sound pressure capable of specifying the N1-P2 component is recorded, a value obtained by adding 10 dB to the minimum sound pressure specifying the N1-P2 component is set as the lower limit of the comfortable range. When the N1-P2 component is specified in all of the inspection sounds of the specific frequency, the lower limit of the comfortable range is set to the lower limit of the comfortable range of the normal hearing person. For example, 30 dB.

  The comfort range estimation unit 400 outputs the upper and lower limits of the comfort range for each frequency and the discomfort threshold UCL obtained in step S3080 as measurement results and estimation results. For example, it outputs to a display device such as a display, displays the comfortable range and the unpleasant threshold UCL for each frequency of the inspection sound (S3090), and ends the process.

  In step S4020, the presentation order determination unit 120 determines the number of additions for each inspection sound. In the modification of the second embodiment, the inspection sound is set for the first time, the second time, and the third time similarly to the second embodiment. In the initial setting, the sound pressure interval of the set inspection sound is 20 dB, in the second time the sound pressure interval of the inspection sound is 10 dB, and in the third time, the sound pressure interval is 3 dB and 2 dB. In the present modification, as in the second embodiment, the amount of increase in amplitude is compared per 10 dB increase in the sound pressure of the inspection sound. For this reason, if the interval between the actual set sound pressures becomes small, the influence of the measurement error of the N1-P2 amplitude becomes large, and there is a possibility that the increase / decrease in the increase cannot be correctly determined. Therefore, in order to further reduce the measurement error, the number of times the test sound is presented is increased, and the number of additions when the evoked potential extraction unit 160 performs the averaging in step S1040 is increased to reduce the error. Specifically, the presentation order determination unit 120 stores a predetermined relationship between the sound pressure interval of the inspection sound and the number of additions, and determines the number of inspection sound presentations in the determination of the inspection sound presentation order in step S4020. It is determined according to the relationship between the sound pressure interval and the number of additions.

  FIG. 21 is an example of a table showing the relationship between the sound pressure interval of the inspection sound and the number of additions. In the first step S4020, the presentation order determination unit 120 determines the inspection sound as 30 dBSPL, 50 dBSPL, and 70 dBSPL. In the case of 30 dBSPL, there is no inspection sound with a sound pressure smaller than this, and the interval between the sound pressures of the inspection sounds is infinite, so the number of additions is 10 according to the table of FIG. In the case of 50 dBSPL, since it is 20 dB between 30 dBSPL, the number of additions is 10 times. Similarly, the number of inspection sounds of 70 dBSPL is also 10 times.

  In the second step S4020, the presentation order determination unit 120 determines the inspection sound as 80 dBSPL and 90 dBsPL. Since the 80 dBSPL test sound has an interval of 10 dB with respect to 70 dBSPL, the number of presentations is set to 15 according to the table of FIG. 21, and similarly the 90 dBSPL test sound is set to 15 times.

  In the third step S4020, the presentation order determination unit 120 determines the inspection sound as 93 dBSPL and 95 dBSPL. Since the 93 dBSPL test sound is 3 dB apart from 90 dBSPL, the number of presentations is set to 30 according to the table of FIG. In the 95 dBSPL inspection sound, the interval from 93 dBSPL is 5 dB, so the number of presentations is 30.

  In the auditory test apparatus 20 configured as described above, when the sound pressure interval of the test sound is small, the number of additions is increased to reduce the error of the evoked potential, and when the sound pressure interval of the test sound is small. The influence of increasing error can be suppressed. As a result, the increase / decrease in the increase amount of the amplitude with respect to the increase of the sound pressure can be correctly determined, and the comfortable range and the unpleasant threshold value UCL can be obtained accurately.

  In all of the embodiments and modifications of the present invention, the sound pressure range of the test sound is narrowed sequentially for the first time, the second time, the third time, and the sound pressure difference between the test sounds is further narrowed. It may be set without changing the width of the sound pressure range of the inspection sound. Further, it may be set without changing the difference in sound pressure between inspection sounds.

  In all the embodiments of the present invention and modifications thereof, the order of presenting the inspection sound is determined so as not to continuously present the inspection sound having the same frequency and sound pressure when determining the order of presenting the inspection sound. However, priority may be given to avoiding the continuity of the same frequency, and if the continuation of the frequency is unavoidable, the order of presentation of the inspection sounds may be determined by avoiding the continuation of the same sound pressure. Furthermore, as a method of satisfying the above conditions and determining the presentation order of inspection sounds in a random order, the presentation order determination unit 120 generates random numbers or pseudo-random numbers, and applies inspection sounds to the generated sequence. The presentation order may be determined, or the examination sound presentation order may be determined using a table of one or more random numbers or pseudo-random numbers set in advance.

  In all of the embodiments of the present invention and modifications thereof, it has been described that the sound pressure range of the test sound is determined for one ear and presented only to one ear. Determine the pressure range, determine the number of test sounds for each of the left and right ears, and present the test sounds even if you randomly select which of the left and right ears will be presented good. In addition, when the right and left ear inspection sounds are selected at random, the order of presentation may be determined so as not to be continuously presented to the same ear more than a predetermined number of times, for example, four or more times.

  In all the embodiments and modifications of the present invention, the test sound signal generation unit 130 generates the test sound that realizes the frequency and sound pressure determined by the presentation order determination unit 120. The unit 130 holds a plurality of test sounds having different amplitudes, which can be presented at a sound pressure determined by the presentation order determination unit 120 for a signal of a test sound having a frequency used for a predetermined test. The inspection sound signal corresponding to the frequency and sound pressure of the inspection sound determined by the presentation order determination unit 120 may be selected and output.

  In the first embodiment, the electrode position is measured with the measurement electrode at the top of the head, the reference electrode is attached to the breast projection, and the ground electrode is attached to the root of the nose. The measurement electrode measures the evoked potential in the face and head of the subject. As long as it is possible, the reference electrode may be other than the head, and the reference electrode may be other than the breast projection as long as the evoked potential can be measured differentially with respect to the measurement electrode. As long as it is other than the nose root.

  In all the embodiments and modifications thereof, the N1 latency and amplitude are determined by specifying the negative peak and the positive peak of the evoked potential waveform extracted by addition averaging. A model such as a polynomial or gamma function may be applied, and the minimum and maximum values of the model that minimizes the error may be used. Also, the latency of each component and the N1-P2 amplitude may be determined by applying three straight lines to the three potential changes of the rising edge of N1, the potential change from N1 to P2, and the falling edge of P2. . Further, typical N1-P2 obtained by averaging the auditory evoked potentials obtained from many subjects in advance may be applied as a model to determine the latency and amplitude of each component.

  In the second embodiment, the N1-P2 component is used for the amplitude of the auditory evoked potential, but the value from the negative peak of N1 to the reference point (baseline) may be used as the amplitude.

  In the first embodiment and the modification thereof, the change point is determined by comparing the decrease amount of the latency corresponding to the increase in the sound pressure of the stimulation sound and the discomfort threshold UCL is estimated for the measured N1 latency. Next, the discomfort threshold value UCL is estimated by applying a function such as the reciprocal of the exponent as shown in FIG. Also good. In addition, at the measured N1 latency, the change point is determined by sequentially applying two or three straight lines whose latency decreases with respect to the increase in the sound pressure of the stimulation sound, and the discomfort threshold UCL is estimated. Also good.

  In addition, although the hearing aid adjustment system provided with the auditory test apparatus of Embodiment 1 was demonstrated as a modification of Embodiment 1, it is good also as a hearing aid adjustment system provided with the hearing test apparatus of Embodiment 2. FIG. In this case, as the input / output characteristics of the hearing aid, when the input is from 30 dBSPL to 70 dBSPL, the output corresponds to the comfortable range, that is, when the input is 30 dBSPL, the output is within the comfortable range of the subject. The lower limit is set, and when 70 dBSPL is input, the output is set to be the upper limit of the subject's comfort range. Alternatively, the comfort level (MCL) is the 30% point close to the upper limit of the comfort range on the logarithmic sound pressure axis of the comfort range, and the output is MCL of the subject when 60 dBSPL is input. Set the input / output characteristics of the hearing aid so that

  The auditory inspection device according to the present invention can be widely used when measuring auditory function, and can adjust the output of an acoustic device such as a speaker or a headphone, or a device that compensates for the auditory function such as a hearing aid. This is useful when building a device that adjusts to the above state.

DESCRIPTION OF SYMBOLS 10, 20 Hearing test | inspection apparatus 15 Hearing aid adjustment system 100 Test subject 110 Test sound range determination part 120 Presentation order determination part 120
DESCRIPTION OF SYMBOLS 130 Test sound production | generation part 140,240 Test sound output part 150 EEG measurement part 160 Evoked potential extraction part 170 N1 determination part 180 Latency calculation part 190 Intensity latency relation storage part 200 UCL estimation part 210 HTL acquisition part 220 Temporary UCL setting part 230 Hearing Aid Characteristic Setting Unit 250 Hearing Aid 300, 310 Operation Unit 370 N1-P2 Determination Unit 380 Amplitude Calculation Unit 390 Intensity Amplitude Relationship Storage Unit 400 Comfortable Range Estimation Unit

Claims (11)

An inspection sound range setting unit for setting a plurality of types of inspection sounds defined by a combination of at least three different sound pressures and at least two types of frequencies;
A presentation order determination unit for determining a presentation order of the plurality of types of inspection sounds so that inspection sounds of the same frequency or the same sound pressure are not continuously presented;
An inspection sound output unit for outputting the plurality of types of inspection sounds in the determined order of presentation;
An electroencephalogram measurement unit for measuring the electroencephalogram of the subject;
The evoked potentials evoked by the test sounds having the same frequency f and different sound pressures a, b, and c (a <b <c) are extracted from the measured electroencephalograms to obtain the test sound having the sound pressure a. The latency or amplitude of the corresponding evoked potential A, the latency or amplitude of the evoked potential B corresponding to the test sound of sound pressure b, and the latency or amplitude C of the evoked potential C corresponding to the test sound of sound pressure c A computing unit for computing
A first difference between the latency or amplitude of the evoked potential A and the latency or amplitude of the evoked potential B, and a second difference between the latency or amplitude of the evoked potential B and the latency or amplitude of the evoked potential C. A difference is calculated, and when the change amount of the second difference with respect to the first difference is equal to or greater than a predetermined value, the frequency f is determined based on a predetermined relationship between the change amount and the sound pressure. An auditory examination apparatus comprising: an estimation unit that estimates a discomfort threshold in   The said calculating part is provided with the N1 determination part which extracts the negative component N1 which appears after about 100 milliseconds from the time when each test | inspection sound was shown as an evoked potential induced by each said test | inspection sound. The hearing test apparatus according to 1.   The auditory examination apparatus according to claim 2, wherein the calculation unit includes a latency calculation unit that calculates the latency of each negative component N1 of the evoked potential A, the evoked potential B, and the evoked potential C. When the change amount of the second difference with respect to the first difference is smaller than a predetermined value,
The inspection sound range setting unit further sets at least two types of sound pressures d and e (c <d <e) higher than the sound pressure c for the inspection sound of the frequency f,
The presentation order determination unit further determines a presentation order of a plurality of types of inspection sounds including a set inspection sound,
The inspection sound output unit outputs the plurality of types of inspection sounds in the determined order of presentation,
The calculation unit calculates the latency or amplitude of the evoked potential D corresponding to the test sound of the sound pressure d and the latency or amplitude of the evoked potential E corresponding to the test sound of the sound pressure e,
The estimation unit includes a third difference between the latency or amplitude of the evoked potential C and the latency or amplitude of the evoked potential D, and the latency or amplitude of the evoked potential D and the latency of the evoked potential E or A fourth difference with the amplitude is calculated, and when the change amount of the fourth difference with respect to the third difference is not less than the predetermined value, the frequency is calculated based on the relationship between the change amount and sound pressure. The hearing test apparatus according to claim 1, wherein a discomfort threshold for f is estimated. A storage unit that holds a table indicating a relationship between the amount of change and the added value related to the sound pressure;
The estimation unit refers to the table based on the change amount, acquires an addition value corresponding to the change amount, and estimates a sum of the sound pressure c and the addition value as the discomfort threshold. The hearing test apparatus according to 1. The presentation order determination unit determines a presentation order so as to present each of the plurality of types of inspection sounds a plurality of times,
The auditory test apparatus according to claim 1, wherein the calculation unit extracts the evoked potentials induced by the test sounds by adding the evoked potentials induced by the test sounds having the same frequency and sound pressure.   The auditory examination apparatus according to claim 6, wherein the calculation unit increases the number of times of evoked potential addition as the sound pressure interval of the plurality of examination sounds is smaller. The computing unit is
An extraction unit for extracting an evoked potential induced by each inspection sound;
From the evoked potential, N1-P2 that extracts a negative component N1 that appears after about 100 milliseconds from the time when each test sound is presented, and a positive component P2 that appears after about 200 milliseconds from the time An extractor;
An amplitude calculation unit that calculates an N1-P2 amplitude that is an absolute value of a difference between the negative component N1 and the positive component P2.
The estimator can be heard from the N1-P2 amplitude at the frequency f based on the N1-P2 amplitude and a predetermined relationship between the N1-P2 amplitude and the sound pressure. The hearing test apparatus according to claim 1, wherein the comfort range and the discomfort threshold are estimated. A hearing test apparatus according to claim 1;
An acquisition unit for acquiring a minimum audible value of a predetermined frequency;
A setting unit for setting a provisional discomfort threshold based on the minimum audible value;
A characteristic setting section;
A hearing aid adjustment system comprising a hearing aid and
The test sound range setting unit of the hearing test apparatus sets the plurality of types of test sounds based on the minimum audible value acquired by the acquisition unit,
The hearing aid adjustment system, wherein the characteristic setting unit sets an input / output characteristic of the hearing aid based on the minimum audible value acquired by the acquisition unit and the discomfort threshold estimated by the hearing test apparatus. Setting a plurality of types of inspection sounds defined by a combination of at least three different sound pressures and at least two types of frequencies;
Determining the order of presenting the plurality of types of test sounds so that test sounds of the same frequency or the same sound pressure are not continuously presented;
Outputting the plurality of types of inspection sounds in the determined order of presentation;
Measuring the subject's brain waves;
The evoked potentials evoked by the test sounds having the same frequency f and different sound pressures a, b, and c (a <b <c) are extracted from the measured electroencephalograms to obtain the test sound having the sound pressure a. The latency or amplitude of the corresponding evoked potential A, the latency or amplitude of the evoked potential B corresponding to the test sound of sound pressure b, and the latency or amplitude C of the evoked potential C corresponding to the test sound of sound pressure c A step of calculating
A first difference between the latency or amplitude of the evoked potential A and the latency or amplitude of the evoked potential B, and a second difference between the latency or amplitude of the evoked potential B and the latency or amplitude of the evoked potential C. A difference is calculated, and when the change amount of the second difference with respect to the first difference is equal to or greater than a predetermined value, the frequency f is determined based on a predetermined relationship between the change amount and the sound pressure. A method of auditory examination, comprising: estimating a discomfort threshold at. A computer program executed by a computer provided in the hearing aid adjustment system,
The computer program is for a computer implemented in the hearing aid adjustment system,
Setting a plurality of types of inspection sounds defined by a combination of at least three different sound pressures and at least two types of frequencies;
Determining the order of presenting the plurality of types of test sounds so that test sounds of the same frequency or the same sound pressure are not continuously presented;
Outputting the plurality of types of inspection sounds in the determined order of presentation;
Receiving the measured brain waves of the subject;
The evoked potentials evoked by the test sounds having the same frequency f and different sound pressures a, b, and c (a <b <c) are extracted from the measured electroencephalograms to obtain the test sound having the sound pressure a. The latency or amplitude of the corresponding evoked potential A, the latency or amplitude of the evoked potential B corresponding to the test sound of sound pressure b, and the latency or amplitude C of the evoked potential C corresponding to the test sound of sound pressure c A step of calculating
A first difference between the latency or amplitude of the evoked potential A and the latency or amplitude of the evoked potential B, and a second difference between the latency or amplitude of the evoked potential B and the latency or amplitude of the evoked potential C. A difference is calculated, and when the change amount of the second difference with respect to the first difference is equal to or greater than a predetermined value, the frequency f is determined based on a predetermined relationship between the change amount and the sound pressure. A computer program for executing the step of estimating a discomfort threshold in

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