Mastication detection device, mastication detection program, mastication detection method, and electrical taste stimulation device

Abstract

A mastication detection device comprising: a sensor that is mounted on a lower jaw side surface; and a mastication detection unit that executes, on the basis of a dead time setting and with hysteresis, detection of a positive-slope zero crossing from a detection signal from the sensor, executes a comparison of the detection signal from the sensor with a threshold value for detecting mastication activity when a positive-slope zero crossing is detected, and detects, on the basis of the comparison result, whether a continuous activity performed by a person wearing the sensor is mastication activity.

Description

Mastication detection device, mastication detection program, mastication detection method, and gustatory electrical stimulation device

[0001] The present invention relates to a mastication detection device, a mastication detection program, a mastication detection method, and a gustatory electrical stimulation device.

[0002] Patent Document 1 discloses a taste presentation device that can enhance the taste modification effect while suppressing the user's discomfort. Patent Document 2 discloses an inexpensive input device suitable for wearable computers. Patent Document 3 discloses a gustatory electrical stimulation device that enables taste adjustment, such as continuous taste enhancement. Patent Document 4 discloses a chewing frequency detection device for detecting the number of chews a person makes. Patent Document 5 discloses a chewing frequency recording device that records and displays the number of chews. Patent Document 6 discloses a masticatory sensory foot device that provides a pseudo-chewable texture without causing discomfort to the user even when chewing care food with a poor texture, thereby improving the satisfaction and enjoyment of the meal and further allowing the user to feel that they are chewing themselves, thereby preventing aspiration, ensuring the number of chews, and maintaining and improving masticatory ability. Non-Patent Document 1 discloses that chewing can be visualized using the appearance and application of a chewing meter with the product name "bitescan."

[0003] International Publication No. 2023 / 022223 Patent No. 5543929 JP 2018-42991 A JP 2008-48791 A JP 7-171136 A JP 2016-93476 A

[0004] https: / / jp.sharp / business / bitescan /

[0005] However, no technology has been developed that can accurately detect chewing.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a chewing detection device, a chewing detection program, and a chewing detection method that can accurately detect chewing, as well as a gustatory electrical stimulation device that can accurately detect chewing and thereby apply appropriate electrical stimulation at appropriate times.

[0007] In order to solve the above-mentioned problems and achieve the object, the chewing detection device of the present invention comprises a sensor attached to the side of the lower jaw, and a chewing detection unit that detects a rising zero cross from a detection signal from the sensor with hysteresis based on a dead time setting, compares the detection signal from the sensor with a threshold value for detecting chewing actions when a rising zero cross is detected, and detects whether a continuous action performed by a person wearing the sensor is a chewing action based on the result of the comparison.

[0008] In addition, the chewing detection device according to the present invention may further include a filtering unit that performs a predetermined filtering process on the detection signal from the sensor, and the chewing detection unit may perform the detection and the comparison based on the detection signal after the predetermined filtering process has been performed.

[0009] The predetermined filtering process may include at least one of band-pass filtering, low-pass filtering, and removal of DC components.

[0010] The sensor may also be an optical sensor.

[0011] The sensor may also be attached to the outer ear or the temporomandibular joint.

[0012] The sensor may also be attached to the pinna or ear canal.

[0013] The sensor may also detect a change in the shape of the ear canal as a change in distance.

[0014] The change in shape of the ear canal may also be continuous.

[0015] The sensor may also include a detection element that is placed at a predetermined position in the outer ear, and an elastic member that abuts against the ear canal and surrounds the detection element.

[0016] The sensor may also be a reflective photosensor or an FBG optical fiber sensor.

[0017] Furthermore, the gustatory electrical stimulation device of the present invention includes the chewing detection device of the present invention; a cathode that is attached to a first region which is one of the regions at the back of the head and the back of the neck of the person or a second region which is one of the regions around the oral cavity and the jaw of the person; an anode that is installed at the second region of the person when the cathode is attached to the first region of the person and that is installed at the first region of the person when the cathode is attached to the second region of the person; and an electrical signal generating unit that applies an electrical signal between the anode and the cathode based on the detection result of the chewing detection device, and the electrical signal generating unit outputs a signal having a convex waveform at a predetermined frequency.

[0018] In addition, the electrical signal generating unit may continuously output an electrical signal of a specific intensity while the chewing detection device detects that the continuous action performed by the person is a chewing action, and may stop outputting the electrical signal when the chewing detection device no longer detects that the continuous action performed by the person is a chewing action.

[0019] The electrical signal generating section may apply a gradient to the electrical signal and then stop outputting the electrical signal.

[0020] Furthermore, the electrical signal generating unit may output an electrical signal having a specific convex waveform when the number of times the chewing detection device detects that the continuous action performed by the person is a chewing action reaches a predetermined number, and may output the electrical signal having the specific convex waveform again when the number of times the chewing detection device detects that the continuous action performed by the person is a chewing action after the output reaches a predetermined number.

[0021] The electrical signal generating section may control the output of the electrical signal by applying a gradient.

[0022] Furthermore, the chewing detection program of the present invention causes a computer connected to a sensor attached to the side of the lower jaw to detect a rising zero crossing from a detection signal from the sensor with hysteresis based on a dead time setting, and when the zero crossing is detected, compares the detection signal from the sensor with a threshold value for detecting chewing actions, and based on the result of the comparison, functions as a chewing detection means that detects whether a continuous action performed by a person wearing the sensor is a chewing action.

[0023] Furthermore, the chewing detection method of the present invention executes a chewing detection step in which a computer connected to a sensor attached to the side of the lower jaw detects a rising zero crossing from a detection signal from the sensor with hysteresis and based on a dead time setting, and when the zero crossing is detected, compares the detection signal from the sensor with a threshold value for detecting chewing actions, and detects whether a continuous action performed by a person wearing the sensor is a chewing action based on the result of the comparison.

[0024] The present invention has the effect of enabling accurate detection of mastication. Furthermore, the present invention has the effect of enabling accurate detection of mastication, thereby enabling appropriate electrical stimulation to be applied at appropriate timing.

[0025] Fig. 1 is a block diagram showing an example of the configuration of a gustatory electrical stimulation device 1. Fig. 2 is a diagram showing the configuration and appearance of a wearable headset in which the gustatory electrical stimulation device 1 is implemented. Fig. 3 is a diagram showing the wearable headset shown in Fig. 2 in use. Fig. 4 is a diagram mainly showing an example of detection of a chewing action. Fig. 5 is a diagram mainly showing a first example of current presentation. Fig. 6 is a diagram mainly showing a second example of current presentation.

[0026] Hereinafter, embodiments of a mastication detection device, a mastication detection program, a mastication detection method, and a gustatory electrical stimulation device according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments. The present invention is not intended to be limited to the embodiments described below and the configurations shown in the drawings, and includes configurations equivalent thereto. In particular, in this embodiment, a case in which a mastication detection device is mounted on a gustatory electrical stimulation device will be described as an example, but the present invention is not limited to this example.

[0027] [1. Overview of electrical taste stimulation] Electrical taste stimulation around the oral cavity has been attracting attention in recent years as a next-generation salt reduction technology. A device for electrical taste stimulation around the oral cavity may be used as a "novel seasoning" that can further reduce salt intake and improve the deliciousness of food.

[0028] However, conventional gustatory electrical stimulation devices require the user to manually turn on the electrical stimulation switch every time they bring food to their mouth, making them inconvenient to use. Furthermore, conventional gustatory electrical stimulation devices require a preset electrical stimulation time (e.g., 30 seconds) and, when the switch is turned on, provide electrical stimulation for that time. This means that current continues to flow through the user even after the user has finished chewing and swallowing, potentially causing the user to feel uneasy or uncomfortable.

[0029] Therefore, in this embodiment, by detecting chewing, it is possible to apply appropriate electrical stimulation to the user at appropriate timing. Specifically, in this embodiment, by detecting chewing and swallowing by the user and automatically controlling ON / OFF of the electrical stimulation, it is possible to improve convenience and reduce the risk of the user receiving unnecessary electrical stimulation.

[0030] [2. Configuration] Figure 1 is a block diagram showing an example of the configuration of a gustatory electrical stimulation device 1. The gustatory electrical stimulation device 1 includes a sensor unit 10, a mastication detection unit 12 (corresponding to the mastication detection device of the present invention), an electrical signal generation unit 14, and electrodes 16 (anode 16a and cathode 16b). Types of tastes that can be modified by the gustatory electrical stimulation device 1 include, for example, basic tastes (sweetness, sourness, saltiness, bitterness, and umami), richness, fattiness, and spice. For reference, the configuration and appearance of a wearable headset (corresponding to an example of a wearable computer) equipped with the gustatory electrical stimulation device 1 are shown in Figure 2, and the wearable headset in use is shown in Figure 3.

[0031] [2-1. Configuration of Sensor Unit (See FIGS. 1 and 2)] The sensor unit 10 is attached to a body part (for example, the outer ear (pinna or ear canal) or the side of the mandible, such as the temporomandibular joint). The sensor unit 10 may also be attached to a natural orifice, for example. Here, "natural orifice of the body" refers to an opening of an organ or the like formed in the body, such as the outer ear (ear canal), nasal cavity, oral cavity, anus, or vagina. In this embodiment, the outer ear (including the ear canal) is particularly used as the natural orifice of the body. Note that, although various types of sensor unit 10 can be used, it is preferable to employ an optical sensor (for example, a reflective photosensor or an FBG optical sensor) that can measure the distance to a measurement object using light. An optical sensor includes a light-emitting element such as an LED or a light bulb and a light-receiving element such as a phototransistor, a photodiode, or a CCD. Note that when an infrared LED is used as the LED, the emitted infrared light must have a wavelength that does not penetrate the human body. In the following description of this embodiment, the sensor unit 10 is an optical sensor. The shape of the sensor unit 10 is preferably an "ear hook type" or an "insertion type" because of its ease of use.

[0032] (Ear-hook type) In the ear-hook type, the sensor unit 10 is attached to the ear from the outside without actually being inserted into the ear canal. Therefore, once attached, the relative position of the sensor unit 10 with respect to the ear canal is substantially fixed. However, the shape of the ear canal changes in different ways depending on the location. For example, the part of the ear canal that changes shape when the tongue moves is different from the part that changes shape when the eyeball moves. Therefore, it is preferable to adjust the attachment direction of the sensor unit 10 with respect to the ear depending on the action to be measured. In this case, the direction of the entire sensor unit 10 may be adjusted, or it is also possible to adjust the direction of only the detection element.

[0033] The sensor unit 10 has a transmitter element and a receiver element as detector elements. A portion of the measurement light emitted from the transmitter element is reflected by the surface of the ear canal and returns to the receiver element. When the outer ear of the wearer of the sensor unit 10 moves, the distance from the detector element of the sensor unit 10 to the reflective surface of the ear canal changes. This changes the intensity of the reflected light incident on the detector element (receiver element). Therefore, by monitoring this change in the intensity of the reflected light, changes in the shape of the ear canal can be detected. Multiple detector elements can be provided as needed. Examples of emitters include light-emitting elements such as LEDs and light bulbs, and examples of receivers include light-receiving elements such as phototransistors, photodiodes, and CCDs. In particular, using an LED as the transmitter element and a phototransistor or photodiode as the receiver element reduces noise in the detection signal, resulting in a high-quality detection signal.

[0034] (Insertion Type) In the insertion type, the transmitting element and receiving element serving as the detecting element have a structure surrounded by an elastic member. When the sensor unit 10 is inserted into the ear canal, the elastic member abuts against the surface of the ear canal. Therefore, even after the sensor unit 10 is inserted into a predetermined position in the ear canal, the elastic member bends, allowing the detecting element to move within the wearer's ear canal. On the other hand, even if the shape of the ear canal changes, the wearer's eardrum does not move significantly. Therefore, the detecting element can move slightly relative to the eardrum.

[0035] As mentioned above, the shape change of the ear canal varies depending on the location. Therefore, by appropriately adjusting the shape and hardness of the elastic member, the detection element of the sensor unit 10 can easily detect the shape change of a specific part of the ear canal. As a result, the sensor unit 10 can respond only to the specific movement of the wearer. It is also effective to combine a relatively hard member and a relatively soft member as the elastic member. This allows for more precise adjustment.

[0036] A portion of the measurement light emitted from the transmitting element is reflected by the surface of the eardrum and returns to the receiving element. When the shape of the ear canal changes, the elastic member bends, causing the detecting element to move slightly relative to the eardrum, changing the distance from the detecting element to the reflecting surface of the eardrum. This changes the intensity of the reflected light incident on the detecting element (receiving element). Therefore, by monitoring this change in the intensity of the reflected light, changes in the shape of the ear canal can be detected. Multiple detecting elements can be provided as needed.

[0037] In an insertion-type sensor unit, the above-described relative movement of the detection elements can be used to amplify the detection signal, which will be described later. This amplification due to relative movement is not electrical but is due to the mechanism of the sensor unit 10. Therefore, the amplified signal is a high-quality signal with an excellent S / N ratio.

[0038] [2-2. Configuration of the Mastication Detection Unit (See FIG. 4)] The mastication detection unit 12 can be realized by, for example, a computer. When the detection element (receiving element) of the sensor unit 10 receives reflected light, the sensor unit 10 generates a detection signal according to the detection intensity and transmits this to the mastication detection unit 12. When the mastication detection unit 12 receives the detection signal from the sensor unit 10, the mastication detection unit 12 detects a zero crossing of the rising edge from the detection signal with hysteresis based on a set dead time (e.g., 300 ms, etc.). When a zero crossing of the rising edge is detected, the mastication detection unit 12 compares the detection signal with a threshold value for detecting a mastication action, and detects whether a continuous action (hereinafter referred to as a "continuous action") performed by a person wearing the sensor unit 10 (hereinafter referred to as a "wearer") is a mastication action based on the comparison result. Here, the mastication detection unit 12 may include a filtering unit that performs a predetermined filtering process (for example, at least one process selected from the group consisting of a band-pass filter, a low-pass filter, and removal of DC components) on the detection signal. When the mastication detection unit 12 includes a filtering unit, the mastication detection unit 12 detects a zero crossing of the rising edge and compares the detection signal with a threshold value based on the detection signal after the predetermined filtering process (see FIG. 4).

[0039] In this embodiment, a dead time is set so as to respond only to waveforms that resemble chewing rhythms. Furthermore, in detecting chewing movements, the chewing detection unit 12 may detect that a continuous movement is chewing when the detection signal exceeds a threshold (see FIG. 4). Furthermore, in filtering, it is preferable to apply a band-pass filter or a low-pass filter to an extent that the waveform characteristics are not lost. For example, it is preferable to set the band-pass (low-pass) coefficient to a value in the range of 0.2 to 0.4 based on the actually measured detection signal (sensor value). Furthermore, to prevent erroneous detection, such as detecting a continuous movement that is actually a movement other than chewing (e.g., speech, body movement, pushing the sensor unit 10 into the outer ear, or removing the sensor unit 10 from the outer ear) as chewing, a strong low-pass filter or attention to the waveform may be applied.

[0040] [2-3. Configuration of the Electrical Signal Generator (See FIGS. 5 and 6)] The electrical signal generator 14 can be realized, for example, by a boost circuit, an operational amplifier, and peripheral circuits as a current control means, and a current sensor IC and peripheral circuits as a current measurement means. The electrical signal generator 14 applies an electrical signal between the anode 16a and the cathode 16b based on the detection result of the chewing detection unit 12. The electrical signal generator 14 outputs a signal having a convex waveform at a predetermined frequency.

[0041] Here, the electrical signal generating unit 14 may output an electrical signal having a specific convex waveform when the number of times that the mastication detection unit 12 detects that the continuous motion is a mastication motion reaches a predetermined number (e.g., four times), and may output the electrical signal having the specific convex waveform again when the number of times that the mastication detection unit 12 detects that the continuous motion is a mastication motion reaches a predetermined number (e.g., four times) after the output (see FIG. 5 ). Note that the electrical signal generating unit 14 may control the output of the electrical signal by applying a gradient. Controlling the output of the electrical signal by applying a gradient can suppress intraocular flashes caused by electrical stimulation in the user, thereby improving the usability of the gustatory electrical stimulation device 1.

[0042] Furthermore, the electrical signal generating unit 14 may continuously output an electrical signal of a specific intensity while the mastication detection unit 12 detects that the continuous motion is a mastication motion, and may stop outputting the electrical signal when the mastication detection unit 12 no longer detects that the continuous motion is a mastication motion (see FIG. 6 ). Note that the electrical signal generating unit 14 may apply a gradient to stop outputting the electrical signal. Applying a gradient to stop outputting the electrical signal reduces intraocular flashes caused by electrical stimulation in the user, thereby improving the usability of the gustatory electrical stimulation device 1.

[0043] [2-4. Electrode Configuration (See FIGS. 1, 2, and 3)] The electrode 16 is composed of an anode 16a that is placed at one site (first site) on the back of the head and the back of the neck of the wearer or one site (second site) around the mouth and jaw of the wearer, and a cathode 16b that is placed at a second site on the wearer when the anode 16a is placed at the first site on the wearer, and that is placed at the first site on the wearer when the anode 16a is placed at the second site on the wearer.

[0044] According to the gustatory electrical stimulation device 1 configured as described above, the sensor unit 10 is attached to the side of the mandible (the ear canal in this embodiment), making it possible to detect changes in the shape of the side of the mandible in an environment where disturbance factors such as external light are minimized. As a result, a highly reliable detection signal can be stably obtained from the sensor unit 10. Based on the obtained detection signal, it is possible to accurately detect chewing movements and apply appropriate electrical stimulation to the wearer at appropriate timing.

[0045] The sensor unit 10 is not limited to an optical sensor. Any other sensor may be used as the sensor unit 10 as long as it is attached to the side of the lower jaw of the body and can detect changes in the shape of the side of the lower jaw.

[0046] For example, the sensor unit 10 may be an acoustic sensor. The sensor unit 10 has a transmitter element and a receiver element as detector elements. Examples of acoustic sensors include ultrasonic distance sensors. Examples of the transmitter element include a speaker, and examples of the receiver element include a microphone. A portion of the measurement wave emitted from the transmitter element is reflected by the surface of the ear canal and returns to the receiver element. When the wearer's outer ear moves, the distance from the detector element of the sensor unit 10 to the reflecting surface of the ear canal changes. This changes the time it takes for the reflected wave to enter the detector element (receiver element). Therefore, by monitoring this change over time, changes in the shape of the ear canal can be detected. The frequency of the sound wave used for the measurement wave can be, for example, 20 kHz or higher, which is undetectable by human hearing. The sensor unit 10 may also be capable of detecting chewing sounds (see, for example, JP 2019-047859 A or JP 2012-196284 A).

[0047] For example, the sensor unit 10 can be an FBG (Fiber Bragg Grating) optical fiber sensor. An FBG optical fiber sensor generates a certain structural change in an optical fiber and uses the structural change as a diffraction grating to capture a specific wavelength passing through the optical fiber. The optical fiber of the FBG optical fiber sensor is aligned with the surface of the ear canal so that the optical fiber deforms with movement of the outer ear. When the optical fiber deforms, the wavelength of the light passing through the optical fiber changes, and by monitoring the wavelength change, it is possible to detect changes in the ear canal associated with movement of the outer ear.

[0048] Furthermore, when an acoustic sensor or an optical sensor as in this embodiment is used as the sensor unit 10, there is no need to forcefully insert the sensor unit 10 into a natural opening in the body, as is the case with a pressure sensor. This reduces discomfort to the wearer. As a result, the sensor unit 10 can be worn for long periods of time, making it suitable for use as a sensor unit 10.

[0049] In addition, when an optical sensor is used for the sensor unit 10, the structure of the sensor unit 10 can be simplified compared to a pressure sensor or the like, and there is also the advantage that it can be constructed more inexpensively.

[0050] The gustatory galvanic stimulation device 1 can also be used to improve the quality of life of people who need to limit their excessive salt intake, such as patients with chronic kidney disease or high blood pressure. Specifically, the gustatory galvanic stimulation device 1 can be used to relieve the anxiety felt by those who cannot reduce their salt intake and are worried about when their symptoms will worsen. The gustatory galvanic stimulation device 1 can also be used to create the pleasure of occasionally eating something quite salty.

[0051] Furthermore, the gustatory electrical stimulation device 1 can be used to support lifestyle improvement using mastication information. Specifically, the gustatory electrical stimulation device 1 can visualize the number of chews, chewing strength, and chewing time, allowing for real-time monitoring of, for example, the number of chews per mouthful and the level of masticatory force. The gustatory electrical stimulation device 1 may adjust the strength, frequency, or duration of the electrical stimulation, or the type of taste provided, depending on mastication conditions such as the number of chews, chewing strength, and chewing time. It has been reported that a low number of chews per mouthful results in less stimulation of the satiety center, leading to increased food intake and increased susceptibility to obesity, and that a decrease in masticatory force increases the risk of lifestyle-related diseases. Therefore, for example, if the gustatory electrical stimulation device 1 is IoT-enabled and linked to a smartphone, it will be possible to visualize the user's chewing status, making it easier for the user to improve their lifestyle through chewing. It is also thought that this device can be used to improve the eating behavior of people who need to avoid excessive salt intake, such as patients with chronic kidney disease or high blood pressure.

[0052] Furthermore, the chewing information obtained by the gustatory electrical stimulation device 1 can be utilized in virtual space. In the future, the gustatory electrical stimulation device 1 may be integrated with metaverse-related devices such as VR equipment and utilized to adjust and create the taste of digital foods eaten in virtual space. If the taste change and chewing detection functions can be integrated with metaverse-related devices, users will not only be able to digitize the hardness of the food they are eating in virtual space to adjust the texture of the digital food, but they will also be able to adjust the taste of the digital food with a high degree of freedom using electrical stimulation. Other applications include sensory and physical stimuli such as smell, hot / cold air, and ultrasound.

[0053] The present invention is useful in a variety of industries, such as the food industry, catering industry, medical industry, and entertainment industry.

[0054] REFERENCE SIGNS LIST 1 Electrical gustatory stimulation device 10 Sensor unit 12 Chewing detection unit 14 Electrical signal generation unit 16 Electrode

Claims

1. A chewing detection device comprising: a sensor mounted on the side of the lower jaw; and a chewing detection unit that, from a detection signal from the sensor, detects a rising zero crossing with hysteresis based on a setting of a dead time, and when the rising zero crossing is detected, compares the detection signal from the sensor with a threshold value for detecting a chewing motion, and detects whether a continuous motion performed by the person wearing the sensor is a chewing motion based on the result of the comparison.

2. The chewing detection device according to claim 1, further comprising a filtering unit that performs a predetermined filtering process on the detection signal from the sensor, wherein the chewing detection unit performs the detection and the comparison based on the detection signal after the predetermined filtering process is performed.

3. The chewing detection device according to claim 2, wherein the predetermined filtering process includes at least one of a band-pass filter, a low-pass filter, and removal of a DC component.

4. The chewing detection device according to claim 3, wherein the sensor is an optical sensor.

5. The chewing detection device according to claim 4, wherein the sensor is mounted on the outer ear or the temporomandibular joint.

6. The chewing detection device according to claim 5, wherein the sensor is mounted on the auricle or the ear canal.

7. The chewing detection device according to claim 6, wherein the sensor detects a change in the shape of the ear canal as a change in distance.

8. The chewing detection device according to claim 7, wherein the change in the shape of the ear canal is continuous.

9. The chewing detection device according to claim 8, wherein the sensor includes a detection element disposed at a predetermined position of the outer ear and an elastic member that contacts the ear canal and surrounds the detection element.

10. The chewing detection device according to claim 9, wherein the sensor is a reflection type photosensor or an FBG type optical fiber sensor.

11. The gustatory electrical stimulation device includes: the chewing detection device according to any one of claims 1 to 10; an anode installed at one part of the posterior head and the dorsal side of the neck or at one part of the oral cavity and the periphery of the jaw of the subject; a cathode that is attached to the second part of the subject when the anode is installed at the first part of the subject, and is attached to the first part of the subject when the anode is installed at the second part of the subject; and an electrical signal generation unit that applies an electrical signal between the anode and the cathode based on the detection result of the chewing detection device, wherein the electrical signal generation unit outputs a signal having a convex waveform at a predetermined frequency.

12. The gustatory electrical stimulation device according to claim 11, wherein the electrical signal generation unit continuously outputs an electrical signal with a specific intensity while the chewing detection device detects that the continuous movement performed by the subject is a chewing movement, and stops outputting the electrical signal when the chewing detection device no longer detects that the continuous movement performed by the subject is a chewing movement.

13. The gustatory electrical stimulation device according to claim 12, wherein the electrical signal generation unit stops outputting the electrical signal with a gradient.

14. The gustatory electrical stimulation device according to claim 11, wherein the electrical signal generation unit outputs an electrical signal having a specific convex waveform when the number of times the chewing detection device detects that the continuous movement performed by the subject is a chewing movement reaches a predetermined number of times, and outputs the electrical signal having the specific convex waveform again when the number of times the chewing detection device detects that the continuous movement performed by the subject is a chewing movement reaches the predetermined number of times after the output.

15. The gustatory electrical stimulation device according to claim 14, wherein the electrical signal generation unit controls the output of the electrical signal with a gradient.

16. A chewing detection program for causing a computer connected to a sensor attached to the side of the lower jaw to function as a chewing detection means for detecting whether a continuous movement performed by the person wearing the sensor is a chewing movement. The computer executes detection of the rising zero crossing from the detection signal from the sensor with hysteresis based on the setting of the dead time, and when the zero crossing is detected, executes comparison between the detection signal from the sensor and a threshold value for detecting a chewing movement, and based on the result of the comparison.

17. A chewing detection method, wherein a computer connected to a sensor mounted on the side of the lower jaw part executes detection of a rising zero cross from a detection signal from the sensor with hysteresis based on setting of a dead time, and when the zero cross is detected, executes comparison between the detection signal from the sensor and a threshold value for detecting a chewing motion, and based on a result of the comparison, detects whether a continuous motion performed by a person wearing the sensor is a chewing motion.

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