JP7145484B2 - Masticatory motion measuring device, masticatory motion measuring method, and method for acquiring data related to masticatory motion - Google Patents

Description

TECHNICAL FIELD The present invention relates to a device for measuring chewing motion from the potential difference in and around the left and right ears.

In order to measure and evaluate masticatory motion, image measurement of jaw movement, measurement of head surface deformation accompanying masticatory motion, measurement of electrical activity of muscles related to masticatory motion, etc. have been performed (Patent Document 1- 3, Non-Patent Documents 1, 2).
For example, Patent Literature 1 discloses a mastication sensory feedback device for simulating mastication, which includes a mastication detector attached to the vicinity of a user's mouth-closing muscle, a myoelectric sensor for measuring the myoelectricity, Disclosed is a mastication sensation feedback device provided with a sound presentation device worn on the user's ear for simulating mastication sounds.
In addition, Patent Document 2 discloses an eating habits management device that can accurately and simply check the mastication state, and is attached to the head of the diner in a headband or neckband style, and the temporal muscle of the diner is attached to the head of the diner. Disclosed is an apparatus including means for detecting movement of a body.
In addition, Non-Patent Document 1 measures the electromyogram waveform of the masseter muscle from an electrode attached on the masseter muscle, filters the electromyogram waveform, and makes it sound as a pseudo mastication sound to the subject. changes (results in a crunchy sensation). In addition, Non-Patent Document 2 describes the psychological effects of applying the technique of Non-Patent Document 1 to nursing care food. Electromyograms in Non-Patent Documents 1 and 2 are derived from electrodes attached to the masseter muscle

In this way, the activities of muscles involved in mastication, such as the masseter muscle and the temporalis muscle, have conventionally been measured by attaching electrodes to the body surface of these muscles. However, there are problems such as complicated operations associated with searching for and attaching the electrode attachment positions, and noise effects due to changes in the contact state of the electrodes due to deformation of the body surface associated with mastication.

Here, there are some reports on devices that detect mastication motions near the ears away from the masseter and temporal muscles, instead of measuring them on the body surface above the muscles such as the masseter and temporal muscles.
For example, Patent Document 4 discloses a meal time estimation device for estimating a user's meal time, which includes detection means for detecting a physical state related to mastication and calculation means for calculating a mastication feature quantity based on measurement data. , a mealtime estimation device comprising: determination means for determining a meal feature amount indicating a tendency of mastication from the mastication feature amount; and estimation means for estimating a user's meal time from the meal feature amount. Further, it is described that the detection unit of the meal time estimation device acquires and uses the data measured by the input unit of the wearable device, and the input unit is attached to the temple, chin, etc., and the skin accompanying mastication is used. Measurements of reflected light, sound, pressure, skin strain, etc. are described. As a specific embodiment, Patent Document 4 uses an optical distance sensor that receives light reflected by the user's outer ear to measure changes in the shape of the auricle, the shape of the external auditory canal, and the position of the eardrum. Disclosed is estimating an action such as chewing. However, the method of Patent Document 4 focuses on the cycle of mastication and characterizes the motion based on the cycle in order to identify the motion of mastication. , and does not extract the feature amount associated with one chewing motion.

Further, Patent Document 5 discloses a bio-worn measuring device for accurately measuring a predetermined motion, which is worn on the ear so as to be clamped between the ear and the head. The body-worn measuring device is equipped with a range-finding sensor, and the displacement of the jaw accompanying mastication (displacement of the distance between the range-finding sensor and the lower part of the back of the ear, displacement of the intensity of light detected by the range-finding sensor, and photoelectric conversion It is disclosed that the number of mastications can be accurately measured by measuring the voltage or current displacement obtained by It also discloses that the device includes a control unit that sets a threshold value for judging mastication, thereby distinguishing between mastication and speech. On the other hand, Patent Literature 5 does not describe measuring muscle activity related to mastication.
Further, Patent Document 6 discloses a muscle activity diagnostic device for detecting facial movements and facial expressions of a person. Disclosed is a muscle activity diagnosis device that identifies a muscle site and activity level based on information on the frequency characteristics and amplitude of each muscle. Patent document 6 describes that when the muscle activity diagnostic device is used, the state of mastication is specified by specifying the waveform of the electromyographic signal in which the muscles of the jaw are active. Furthermore, Patent Literature 6 describes that in the muscle activity diagnostic device, machine learning of measured information can be repeated to improve the accuracy of identifying activities such as mastication.
However, the device of Patent Document 6 requires machine learning in order to increase the accuracy of specifying activities such as mastication, and furthermore, whether or not it can be distinguished from the activity of the jaw muscles during pronunciation is difficult. No description.

JP 2016-093476 A Japanese Patent Application Laid-Open No. 2018-033568 JP-A-11-206740 JP 2016-064078 A JP 2016-131854 A JP 2012-000228 A

Endo H, Ino S, Fujisaki W. The effect of a crunchy pseudo-chewing sound on perceived texture of softened foods. Physiol Behav. 2016; 167: 324-331. Endo H, Ino S, Fujisaki W. Texture-dependent effects of pseudo-chewing sound on perceived food texture and evoked feelings in response to nursing care foods. Appetite. 2017; 116: 493-501.

In order to measure and evaluate masticatory motion, image measurement of jaw movement, measurement of head surface deformation associated with masticatory motion, measurement of electrical activity of muscles related to masticatory motion, etc. have been performed. Among these, the activity of muscles involved in mastication, such as the masseter muscle and the temporalis muscle, has the characteristic that it precedes the actual movement of the jaw, so it is useful as an evaluation value at the start of jaw movement. These are measured using electrodes attached to the body surface over muscles. However, there are problems such as complicated operations associated with searching for and attaching the electrode attachment position, and noise caused by changes in the contact state of the electrodes due to deformation of the body surface associated with mastication.
As described above, in addition to the form in which electrodes are attached to the surface of the muscle, there are those that measure the deformation of the ear by attaching sensors to the outer ear, and those that measure the potential difference between a plurality of electrodes placed on the outer ear. Proposed. Patent Document 5 discloses a device that measures mastication using a distance sensor, and the device includes a movable part so that the position and orientation of the distance sensor can be adjusted. The reason for this is thought to be that the accuracy of the distance measuring sensor varies depending on the installation position and orientation of the sensor, and it is necessary to appropriately adjust this. In addition, since speech also involves some jaw movement, signal processing for distinguishing between speech and mastication is complicated.
As described above, when measuring the deformation of an auricle or the like, it is complicated to determine the mounting position of the sensor and to fix the sensor for accurate measurement. In addition, the type in which a plurality of electrodes are attached in the ear is disadvantageous in terms of signal-to-noise ratio when measuring the signal derived from the electromyogram of mastication because the distance between the electrodes is short.
SUMMARY OF THE INVENTION An object of the present invention is to provide a simple method for measuring electrical activity of muscles related to masticatory motion.

So far, the area around the ear has been used as an indifferent electrode in electroencephalogram and head electromyography measurements. This utilizes the fact that it is less susceptible to potential fluctuations that occur when surrounding tissues such as muscles are active. However, the inventors of the present invention have found that it is possible to measure potential fluctuations from tissue that generates a biopotential, such as surrounding muscles, in and around the ear. Then, when we measured the potential difference measured in or around the left and right ears, we surprisingly found that we could evaluate the timing and strength of mastication separately from speech. The present invention has been completed based on this finding, and includes the following aspects.
That is, in one aspect of the present invention,
[1] A device for measuring mastication,
a set of electric potential detection means for detecting an electric potential generated by mastication, the electric potential detection means being attached to the external auditory canals or auricles on both sides or their periphery;
The present invention also relates to a mastication motion measuring device comprising potential difference calculating means for calculating a difference in potential measured by the pair of potential detecting means.
Here, in one embodiment of the mastication motion measuring device according to the present invention,
[2] The masticatory motion measuring device according to [1] above,
The set of electric potential detection means is characterized in that it detects an electric potential caused only by chewing motion.
Further, in one embodiment of the mastication motion measuring device according to the present invention,
[3] The masticatory motion measuring device according to [1] above,
The set of potential detection means is characterized in that it does not detect potentials generated by actions other than mastication.
Further, in one embodiment of the mastication motion measuring device according to the present invention,
[4] The mastication motion measuring device according to [1] or [2] above,
The motion other than the mastication motion is characterized by being a motion caused by speech.
Further, in one embodiment of the mastication motion measuring device according to the present invention,
[5] The mastication motion measuring device according to any one of [1] to [4] above,
It is characterized in that the potential difference calculating means equally calculates left and right mastication.
Further, in one embodiment of the mastication motion measuring device according to the present invention,
[6] The mastication motion measuring device according to any one of [1] to [5] above,
The masticatory motion is a mouth-closing motion and/or occlusion during mastication, and the electric potential generated by the masticatory motion is a muscle potential of the masseter muscle and/or the temporalis muscle.
Further, in one embodiment of the mastication motion measuring device according to the present invention,
[7] The mastication motion measuring device according to any one of [1] to [6] above,
The potential detecting means may include wet, dry, or insulated electrodes.
Further, in one embodiment of the mastication motion measuring device according to the present invention,
[8] The mastication motion measuring device according to any one of [1] to [7] above,
The masticatory motion measuring device further comprises potential difference information processing means for processing the potential difference information calculated by the potential difference calculating means.
Further, in one embodiment of the mastication motion measuring device according to the present invention,
[9] The mastication motion measuring device according to [8] above,
The processing of the potential difference information by the potential difference information processing means is evaluation of chewing motion.
Further, in one embodiment of the mastication motion measuring device according to the present invention,
[10] The mastication motion measuring device according to [9] above,
The chewing action evaluation is characterized by at least one evaluation selected from the group consisting of chewing timing, chewing strength, chewing frequency, and duration.
In another aspect of the present invention,
[11] A method for measuring mastication, comprising:
an electric potential detection step of attaching a set of electric potential detection means to the external auditory canals or auricles on both sides or the periphery thereof, respectively, and detecting an electric potential generated by mastication;
The present invention relates to a method of measuring a chewing action, including a potential difference calculating step of calculating a potential difference measured by the potential detecting step.
In another aspect of the present invention,
[12] A method for evaluating mastication, comprising:
The present invention relates to a method of evaluating a chewing action, including a step of evaluating the chewing action from potential difference information obtained by the method of measuring a chewing action described in [11] above.
Further, in one embodiment of the method of evaluating chewing motion according to the present invention,
[13] The method of evaluating the mastication action according to [12] above,
The chewing action evaluation is characterized by at least one evaluation selected from the group consisting of chewing timing, chewing strength, chewing frequency, and duration.

According to the masticatory motion measuring device of the present invention, mastication can be detected simply by bringing the electric potential measuring means into contact with both ears, and the orientation and direction of the electrodes as sensors are irrelevant. In the ear or near the ear, the position of the body part can be easily determined, and since there is little hair on the body, it is easy to maintain contact between the electrode and the skin. In addition, since almost no potential difference due to muscle activity appears during speech, it is easy to distinguish between speech and mastication. As an embodiment of the masticatory motion measuring device of the present invention, for example, by using earphones attached to the left and right ears as electrodes as potential measuring means, it is possible to measure muscle activity associated with masticatory motion simply by fitting the earphones into the ears. becomes.
The mastication measuring device according to the present invention has such features, and enables stable measurement of mastication motion regardless of the wearing time or experience of the wearer.
In addition, in the conventional technique of attaching a sensor for measuring chewing motions to one ear, there is a state of one-sided bite, such as chewing food with one of the left and right teeth, so it is easily affected by the side of the bite. However, according to the mastication measuring device according to the present invention, it is possible to measure the mastication motion with little influence of the unilateral bite.

FIG. 1 shows a conceptual diagram showing one embodiment of the mastication motion measuring device of the present invention. The masticatory motion measuring device shown in FIG. FIG. 2 shows a conceptual diagram showing another embodiment of the chewing motion measuring device of the present invention. The masticatory motion measuring device shown in FIG. potential difference calculating means for calculating a difference between two potentials measured by FIG. 3 shows a conceptual diagram showing the form of the mastication motion measuring device of the present invention used in Example 1 below. The masticatory motion measuring device of the present invention includes potential detecting means (electrodes in FIG. 3) attached to the outer ears on both sides, and potential difference calculating means for calculating the difference between the measured potentials. Also disclosed in FIG. 3 is a conventional device in which an electrode is attached directly onto the surface of the left masseter muscle to measure the action potential of the masseter muscle. 4A and 4B show a conventional measuring device (FIG. 4A) and a chewing motion measuring device according to the present invention (FIG. 4B) when the subject masticates on the left side of the oral cavity in the embodiment shown in FIG. The measured potential difference is shown (FIG. 4A shows the measurement result by the conventional measuring device, and FIG. 4B shows the measurement result by the mastication motion measuring device according to the present invention). Moreover, FIG. 4C shows the result of measuring the sound signal with a microphone when the subject masticates on the left side of the oral cavity in the embodiment shown in FIG. 5A and 5B show a conventional measuring device (FIG. 5A) and a chewing motion measuring device according to the present invention (FIG. 5B) when the subject masticates on the right side of the oral cavity in the embodiment shown in FIG. 5A and 5B show measured potential differences (FIG. 5A shows measurement results by a conventional measuring device, and FIG. 5B shows measurement results by a mastication motion measuring device according to the present invention). FIG. 5C shows the result of measuring the sound signal with a microphone when the subject masticates on the right side of the oral cavity in the embodiment shown in FIG. 6A and 6B show the potential difference measured by the conventional measuring device (FIG. 6A) and the chewing motion measuring device according to the present invention (FIG. 6B) when the subject speaks in the embodiment shown in FIG. (FIG. 6A shows the measurement result by the conventional measuring device, and FIG. 6B shows the measurement result by the chewing motion measuring device according to the present invention). FIG. 6C shows the result of measuring the voice signal with a microphone when the subject speaks in the embodiment shown in FIG.

The present invention provides a technique for measuring the electric potential in and around the ear, where the body surface is less deformed by mastication, between the left and right ears and measuring the masticatory action from the difference between the electric potentials.
A mastication motion measuring device according to an embodiment of the present invention will be specifically described with reference to FIGS. 1 and 2. FIG. In addition, the embodiment described below is an example, and the measuring device of the present invention is not limited to the following.
FIG. 1 shows an embodiment of a mastication motion measuring device according to the present invention. As shown in FIG. 1, the masticatory motion measuring device according to the present invention comprises potential measuring means 1, 1' to be attached to the auricle or external auditory canal of a subject, or to their peripheral portions. The potential generated by the subject's chewing motion is detected by the potential detecting means 1 and 1', and the two signals detected by the respective potential detecting means are sent to the potential difference calculating means 2 independently. The potential difference calculating means 2 amplifies the two signals detected by the pair of potential measuring means 1 and 1' and calculates the difference (potential difference). In one embodiment of the mastication motion measuring device according to the present invention, the potential difference calculating means 2 includes a differential amplifier 3 and a measuring device 4 as shown in FIG. The differential amplifier 3 calculates and amplifies the difference between the two signals respectively input from the potential measuring means 1 and 1 ′, and transmits a signal containing potential difference information to the measuring instrument 4 . The measuring instrument 4 receives and records the signal transmitted from the differential amplifier 3 .
FIG. 2 shows another embodiment of the chewing motion measuring device according to the present invention. The chewing motion measuring device shown in FIG. 2 includes potential difference information processing means 5 in addition to potential difference calculating means 2 including potential measuring means 1 and 1′, differential amplifier 3 and measuring device 4. FIG. A signal containing potential difference information recorded by the measuring instrument 4 is sent to the potential difference information processing means 5 . The potential difference information processing means 5 evaluates mastication of the subject based on the obtained potential difference information.

As used herein, the term "mastication" refers to chewing and pulverizing food or the like taken into the oral cavity with the teeth. A mastication motion measuring device according to the present invention measures a mastication motion such as crushing and eating food in the oral cavity. In addition, "mastication" includes the action of occlusion in which the teeth of the upper and lower jaws come into contact when chewing food with the teeth. In this specification, the term "chewing" includes occlusion, which is a part of masticatory action, and the chewing action measuring device according to the present invention can measure occlusal action when chewing food or the like with teeth.
"Measurement of chewing action" in the chewing action measuring device according to the present invention detects and measures the electric potentials of the masseter muscle and the temporalis muscle generated during chewing in the auricle, the external auditory canal, or their peripheral parts. Since the masseter muscle and the temporalis muscle are involved in the movement during mastication closing and/or occlusion, the mastication motion measuring device according to the present invention particularly measures the mastication closing and/or occlusion motion.
As used herein, the term “electrical potential generated by mastication” refers to the electric potential of the masseter muscle and the temporalis muscle generated during mastication, particularly when the mouth is closed and/or occlusion, as described above.
The potential detection means 1, 1' for detecting the potential is not particularly limited as long as it can be attached to the auricle, the external auditory canal, or their peripheral parts and can detect changes in the potential associated with mastication. Electrodes can be used. Electrodes as potential detection means can be wet, dry, or insulated. For example, a silver-silver chloride electrode (Kendall electrode, model H124 manufactured by Nippon Covidien Co., Ltd.) used in the following examples can be used.

When the potential detecting means 1, 1' are attached to the auricle, the external auditory canal, or their peripheral parts, the attaching part is not particularly limited, and the tragus, earlobe, helix, triangular fossa, concha, external auditory canal, back of the ear, and these are not particularly limited. may be any site in the vicinity of the . The "peripheral site" refers to a site within about 10 cm from the above-listed ear sites, and may be a site that cannot be said to be on the belly of the masseter or temporalis muscle. For example, even when the potential detection means 1 and 1' are worn in a range of about 10 cm from the tragus to the nose side (in the vicinity of the left and right cheekbones), the chewing motion measuring device according to the present invention can detect the chewing motion of the subject. can be measured. The peripheral site is preferably a site within about 3 cm, more preferably within about 1 cm, of each ear site listed above. In addition, it is preferable that the area is close to the masseter muscle and the temporalis muscle and has thin body hair. A pair of potential detection means 1 and 1' are attached to the auricles or external auditory canals on both sides or their peripheral parts, but the relationship between the attachment parts of the potential detection means is not particularly limited. They may be attached to corresponding positions, or may be attached to different parts of the auricle or ear canal. Preferably, it is a form in which both ears are attached to the same corresponding parts.

The potential detecting means 1, 1' attached to the auricle or the external auditory canal or their peripheral parts detects, in one embodiment, potentials arising only from chewing motions. This is because the action potential of the masseter muscle and the temporalis muscle can be measured in the auricle, the external auditory canal, or their peripheral parts, and the masseter muscle and the temporalis muscle have the property that they are mainly active during mastication. Further, in one embodiment, the potential detection means does not detect a potential generated by an action other than the mastication action. Detecting the potential generated only from the mastication motion or not detecting the potential generated by the motion other than the mastication motion means that the potential generated by the motion other than the mastication motion (for example, speech) is not detected, or is not substantially detected. Say things. “Not substantially detected” means removing potential changes associated with motions other than mastication motions by signal processing such as limiting the signal band.

In the present specification, the "potential difference calculating means 2" is used to calculate the potential difference between the electrodes from two potential signals measured at the auricles or external auditory canals on both sides or their peripheral parts by a pair of potential detecting means 1, 1'. , amplifies the potential difference, extracts a necessary frequency band component, and records or outputs the potential difference information. In one embodiment, the potential difference calculation means 2 can include a differential amplifier 3, a filter, and a measuring instrument 4. FIG. The potential signals detected by the potential detection means 1 and 1' are respectively input to the differential amplifier 3, the potential difference is obtained in the differential amplifier 3, and the potential difference is amplified. The amplified potential difference signal is filtered to extract the desired frequency band components. As the differential amplifier 3, for example, a differential amplifier using an analog operational amplifier can be used. The potential difference amplification factor can range from 100 to 10000 times. A preferred amplification factor is about 1000 times.
As the filter, for example, a bandpass filter is provided so that noise in the potential difference signal can be removed. A filter can, for example, allow the amplified potential difference signal to extract only the frequency band in the range 0 Hz to 5000 Hz. Preferably, it is a form in which only the frequency band in the range of 100 Hz to 1000 Hz can be extracted. It is preferable to set the frequency band to be extracted from 100 Hz to 1000 Hz so that disturbance noise such as noise from the commercial power supply (50 Hz or 60 Hz) and wire vibration can be removed.
The measuring instrument 4 converts the amplified potential difference signal from which the specific frequency band is extracted into digital data as potential difference information and records the digital data. In addition, a signal including potential difference information is sent to the subsequent potential difference information processing means 5 or the like as necessary. Here, the potential difference information includes information such as the number of times of mastication, strength of mastication, timing of mastication, and length of mastication.
In one embodiment, the potential difference calculation means 2 includes a differential amplifier 3 and a filter, and the potential difference signal from which the amplified specific frequency band is extracted is directly sent to the subsequent potential difference information processing means 4 or the like. can be

In one embodiment of the mastication motion measuring device according to the present invention, the potential difference calculation means 1 and 1' equally calculate left and right mastication. Equal calculation of left and right mastication means that there is substantially no difference in potential difference between mastication of food on the left side of the oral cavity and mastication of food on the right side of the oral cavity.
By calculating the left and right mastication equally, it is possible to obtain the effect of stably measuring the number of times of mastication without being affected by the mastication side.

In one embodiment, the masticatory motion measuring device according to the present invention detects the mouth closing motion and/or occlusion during mastication as the masticatory motion, and the electric potential generated by the masticatory motion is the myogenic potential of the masseter muscle and/or the temporalis muscle. is.

In this specification, the "potential difference information processing means 5" is a means for processing the information on the potential difference calculated by the potential difference calculating means 2. For example, quantification and threshold setting for evaluating chewing motion, evaluation of chewing, etc. It is a means that can do Evaluations that can be performed by the potential difference information processing means 5 include, but are not limited to, chewing timing, chewing strength, chewing frequency, and duration. As long as the potential difference information can be processed in this manner, the potential difference information processing means is not limited, and a known calculator or microcomputer can be used.
In addition, the potential difference information processing means 5 can be provided with presenting means for presenting numerical mastication information and its evaluation, and can also be provided with feedback means for giving feedback to the subject based on the obtained mastication information. can. For example, if analog filtering is used, it is possible to generate a pseudo-chewing sound as described in Patent Document 1 and have the wearer listen to it, thereby improving the eating sensation.

(Example 1: Experimental method)
We measured the body surface potential near the left and right ears, and showed that the potential change according to the mastication motion could be measured as the difference between them. It also shows that the potential difference hardly occurs during speech. Therefore, the subjects were instructed to (i) chew the chewing force test gum (Lotte chewing check gum) on the left side of the oral cavity, (ii) chew the chewing force test gum on the right side of the oral cavity, ( iii) Subjects were asked to repeat vowel sounds (“a”, “i”, “u”, “e”, “o”) for about 10 seconds in three different tasks. During the execution of these tasks, we simultaneously measured the body surface potential and voice signals during speech.

The measurement of the body surface potential was performed with the electrode arrangement and the connection state of the measuring device as shown in FIG. First, silver-silver chloride electrodes (Kendall electrodes manufactured by Nippon Covidien Co., Ltd., model H124) for measuring surface electromyography were attached to the left and right earlobes, and these electrodes and differential amplifiers (Wave Plus wireless EMG manufactured by cometa) were used. ) is connected. At the same time, as a conventional measurement method, two silver-silver chloride electrodes for surface electromyography measurement were attached along the vertical direction of the jaw on the skin of the masseter muscle on the left side, and another input terminal of the differential amplifier was used. connected to These two differential amplifiers amplify the potential difference between the electrodes connected to the input terminals, take out the necessary frequency band components, and output them as the potential difference between the output terminals. Here, the amplification factor is 1000 times and the pass frequency band is up to 1 kHz.
The speech signal during speech was measured using a condenser microphone (SONY condenser microphone, model ECM-77B) with an amplifier (ALTO Professional mixer, model ZMX124).
The above-mentioned body surface potential and speech signal during speech were recorded in a general-purpose computer at a sampling frequency of 1 kHz using an AD converter (National Instruments AD converter, model USB-6003).

(result)
FIG. 4 shows the measurement results when chewing gum on the left side of the oral cavity, and shows, from top to bottom, the left masseter muscle electromyographic differential output, the left and right earlobe potential difference output, and the speech signal. The left and right ear lobe potential difference output is obtained in synchronization with the muscle activity of the left masseter muscle differentially derived from the electrodes placed on the left masseter muscle. FIG. 5 shows the measurement results when gum was chewed on the right side of the oral cavity. Even in this case, the left and right earlobe potential difference output was obtained in synchronization with the muscle activity of the left masseter muscle. Furthermore, Fig. 6 shows the measurement results during speech. It can be seen that little muscle activity of the left masseter muscle is observed and the potential difference output between the left and right earlobes is small during speech because the maxillary and mandibular occlusion hardly occurs.

4 and 5, it is possible to see the difference in body surface potential observed depending on whether the gum is chewed on the left or right side in the oral cavity. Comparing the activity of the left masseter muscle, the muscle activity of the left masseter muscle is observed to be greater when chewing on the left side of the mouth than when chewing on the right side of the mouth. However, in the left and right earlobe potential difference output, the effect of the masticatory side in the oral cavity was not observed as much as that observed in the masseter muscle. This means that the left and right earlobe potential difference output is less affected by the mastication side than the unilateral masseter muscle activity, and stable mastication timing detection is possible.
In addition, as shown in Fig. 6, since the bite between the upper and lower jaws hardly occurs during speech, the masseter muscle activity and the left and right earlobe potential difference output were small. It can be seen that the signal is not generated by the force of mastication and occlusion of the upper and lower jaws, but is generated according to the strength of the force of mastication and occlusion.
Therefore, the left and right earlobe potential difference output is considered to be effective in stably measuring the state of mastication and occlusion without being affected by the position of mastication or occlusion in the oral cavity. In addition, in the measurement of the left and right earlobe potential difference output, it is easier to specify the attachment position of the electrode because the attachment position of the electrode can be determined based on the position of the left and right ears compared to the case of measuring the muscle activity of the masseter muscle. . In addition, when attaching the electrodes, it is possible to insert the earphone-shaped electrode into the ear hole or clip the earlobe with the clip-shaped electrode to fix it, making it easy to attach and detach the electrode. There are also benefits.

The device for measuring chewing motion according to the present invention can be applied to, for example, devices listed below.
(1) Simulated mastication sound generator using masticatory activity-related potentials measured by this method (2) Masticatory force evaluation device using mastication activity-related potentials measured by this method (3) Masticatory activity related potentials measured by this method A masticatory sensation feedback device using electrical potential (4) A diet management device using masticatory activity-related potentials measured by this method (5) A mastication frequency counter using mastication activity-related potentials measured by this method (6) This method Meal time estimation device using mastication activity-related potentials measured in (7) Body wearable measuring device using mastication activity-related potentials measured by this method (8) Sleep using mastication activity-related potentials measured by this method Bite bruxism prevention device (9) Occlusal state evaluation device using mastication activity-related potentials measured by this method

1 potential detection means 1′ potential detection means 2 potential difference calculation means 3 differential amplifier 4 measuring instrument 5 potential difference information processing means

Claims (11)

A device for measuring chewing motion, wherein the device comprises a set of potential detecting means for detecting the potential generated by chewing motion, which are attached to the external auditory canals or auricles on both sides or their peripheral parts, respectively. a potential detection means for
potential difference calculation means for calculating a difference in potential measured by the set of potential detection means,
The peripheral part is a part within 10 cm from the ear part, and is a part that cannot be said to be on the belly of the masseter or temporalis muscle,
The masticatory motion measuring device, wherein the set of potential detecting means detects potentials generated only from masticatory motions, and the potential difference calculating means equally calculates left and right mastication. The masticatory motion measuring device according to claim 1,
The set of potential detection means does not detect potentials generated by motions other than mastication motions.
Mastication motion measuring device. The mastication motion measuring device according to claim 1 or 2,
The motion other than the chewing motion is a motion caused by speech,
Mastication motion measuring device. The masticatory motion measuring device according to any one of claims 1 to 3,
The masticatory motion is a mouth-closing motion and/or occlusion during mastication, and the electric potential generated by the masticatory motion is a muscle potential of the masseter muscle and/or the temporalis muscle.
Mastication motion measuring device. The masticatory motion measuring device according to any one of claims 1 to 4,
the potential sensing means comprises wet, dry, or insulated electrodes;
Mastication motion measuring device. The masticatory motion measuring device according to any one of claims 1 to 5,
The masticatory motion measuring device further comprises a potential difference information processing means for processing the potential difference information calculated by the potential difference calculating means.
Mastication motion measuring device. The chewing motion measuring device according to claim 6,
The processing of the potential difference information by the potential difference information processing means is evaluation of chewing motion.
Mastication motion measuring device. The chewing motion measuring device according to claim 7,
The evaluation of the chewing action is at least one evaluation selected from the group consisting of timing of chewing, strength of chewing, number of times of chewing, and duration of chewing.
Mastication motion measuring device. A method for measuring mastication, comprising:
a potential detection step of attaching a set of potential detection means to the external auditory canals or auricles on both sides or their peripheral parts, respectively, and detecting the potential generated only by mastication;
a potential difference calculating step of calculating a difference in potential measured by the potential detecting step, the potential difference calculating step of equally calculating left and right mastication ;
A method of measuring mastication , wherein the peripheral part is a part within 10 cm from the ear part and is not a part on the belly of the masseter muscle or the temporalis muscle . A method for obtaining data on mastication, comprising:
A method of acquiring data on a chewing action, comprising the step of acquiring data on a chewing action from potential difference information obtained by the method for measuring a chewing action according to claim 9 . 11. A method of acquiring data on chewing motion according to claim 10,
The data related to mastication is at least one data selected from the group consisting of mastication timing, mastication strength, number of times of mastication, and duration of mastication.
A method for obtaining data on chewing behavior.

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