JP4730037B2 - Mastication meter - Google Patents

Description

  The present invention relates to a mastication meter for measuring a mastication state.

  It is said that eating by biting things well, that is, increasing the number of chewing cycles, is generally effective not only for maintaining a healthy gastrointestinal tract but also for preventing lifestyle-related diseases. In addition, mastication activates the function of the brain and is said to be effective in preventing dementia.

Thus, an apparatus for counting the number of mastications important for health is provided (for example, Patent Document 1). This device focuses on the point where chewing is mainly performed by the activity of the masseter muscles of the cheeks, detects the movement of the masseter muscles that is tense and relaxed, that is, the displacement corresponding to the change of the muscles as an on / off signal. The number of mastications is detected by counting off signals. Others include a sensor using a tension detection sensor or a muscle voltage detection sensor that is attached to a person's cheek, and a sensor using a pressure sensor that is inserted into the human auditory canal.
JP2003-339675A (paragraph numbers 0003-0004, 0017-0019)

  In the apparatus disclosed in Patent Document 1 described above, the mastication strength cannot be measured only by counting the number of mastications. In addition, since the number of chewing times varies depending on the amount of meal, counting the number of chewing times per mouth is an important element for evaluating the mastication state, but is disclosed in Patent Document 1. The number of chews per mouth could not be measured.

  This invention is made in view of the above-mentioned point, and is providing the mastication meter which can count the frequency | count of mastication for every bite.

  In order to achieve the above object, the invention of claim 1 comprises a triaxial acceleration sensor, a mounting means for pressing the acceleration sensor against the cheek of the person to be measured, and a calculation unit. , An acceleration calculation function for obtaining three-axis combined acceleration from the acceleration detection output of the acceleration sensor, a counting function for counting the number of mastications from the number of times the combined acceleration value exceeds a predetermined threshold, and detection based on a change in the combined acceleration There is a function to estimate the number of times that the food is put in the mouth from the movement of the subject's head and to count the number of times, and a function to calculate the number of times of mastication for each mouth from the number of times of the action and the counted number of mastications. It is characterized by that.

  According to the first aspect of the present invention, the threshold value for detecting mastication from the acceleration value obtained from the acceleration information of the acceleration sensor pressed against the cheek is affected by the head movement by using the three-axis composite acceleration value. Can be determined without any delay, and by using the synthetic acceleration value, the action of putting food into the mouth can be estimated from the movement of the head. As a result, the number of chewing times per mouth, which is an important factor in health management, is obtained. It becomes possible to show.

  According to a second aspect of the present invention, in the first aspect of the present invention, the number of times that the synthesis degree acceleration value exceeds a predetermined threshold value during the period of movement of the head is reduced from the number of chewing times.

  According to the second aspect of the present invention, the accuracy of the number of mastications counted without the noise component due to head movement can be increased.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a function for obtaining a masticatory strength from the combined acceleration value is provided in the calculation unit.

  According to the invention of claim 3, the degree of mastication that can evaluate the condition of teeth and the like can also be measured using the same acceleration sensor, and information that is further effective for health management can be shown to the measurement subject.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the mounting means is formed in the form of an armed headphone or an armless headphone.

  According to the invention of claim 4, it can be easily attached to the person to be measured like the headphone with arm or the armless headphone.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, in the state where the measurement sensor is mounted on the person to be measured, the attachment portion of the acceleration sensor is made extendable so that the position of the acceleration sensor can be adjusted. Features.

  According to invention of Claim 5, according to the position of a to-be-measured person's cheek, an acceleration sensor can be moved to an appropriate position, and a to-be-measured person's individual difference can be absorbed.

  The present invention can determine the threshold for detecting mastication from the acceleration value obtained from the acceleration information of the acceleration sensor pressed against the cheek by using the combined acceleration value of the axis without being affected by the movement of the head. By using the synthetic acceleration value, it is possible to estimate the action of putting food into the mouth from the movement of the head, and as a result it is possible to obtain the number of chewing times per mouth which is an important factor in health management and show it to the subject There is an effect of becoming.

Embodiments of the present invention will be described below.
(Embodiment 1)
As shown in FIG. 1A, the mastication meter 1 according to the present embodiment includes a triaxial acceleration sensor 2 that detects the movement between the tension cities of the masseter that controls the movement of the jaw of the measurement subject as acceleration information, and a micro An operation power source is supplied to the operation unit 3 composed of a computer, a data storage unit 4 composed of a readable and writable non-volatile memory such as a flash memory, a display unit 5 composed of a liquid crystal display, an operation unit 6, and each unit. As shown in FIG. 1 (b), it is incorporated in a phone body 8 on one side (left ear side in the illustrated example) of an armless headphone (as shown in FIG. 1B), and the acceleration sensor 2 is mounted on the jaw. The phone body 8 is used as means for mounting.

  Here, the phone main body 8 stores the calculation unit 3, the battery power source 7, and the data storage unit 4 in addition to the configuration as a normal headphone, exposes the display unit 5 to the outer surface of the phone main body 8, and operates the operation unit 6. The button 91 is exposed, and the acceleration sensor 2 is attached to the tip of the telescopic rod portion 10, and the rod portion 10 is appropriately expanded and contracted in the direction of the arrow in a state where the phone body 8 is hooked on the ear with the ear hook 11. Thus, the acceleration sensor 2 can be pressed against the cheek of the measurement subject.

  Thus, the person using the mastication meter 1 according to the present embodiment moves the acceleration sensor 2 to a position where the acceleration sensor 2 is pressed against the cheek by adjusting the expansion and contraction of the rod portion 10 with the phone main body 8 placed on the ear.

  When the measurement start / stop operation button 91 exposed on the side surface of the phone body 8 is pressed in this state, the calculation unit 3 that has received the operation signal via the operation unit 6 converts the acceleration information from the acceleration sensor 2 into the acceleration information. Based on this, measurement of the chewing state is started.

  The acceleration sensor 2 presses the cheek to detect the movement of the masseter muscle, which controls the movement of the jaw, as acceleration information. FIG. 2 shows an example of a detected waveform of acceleration on each of the axes X, Y, and Z detected by the acceleration sensor 2. The horizontal axis represents time t, and the vertical axis represents acceleration.

  And the movement of tension and relaxation of the masseter during mastication can be detected as a movement perpendicular to the cheek surface, and when only detecting the number of mastications, for example, paying attention only to the Z axis, This can be done by counting the number of times the acceleration value exceeds a certain threshold value L1, and the threshold value L1 used in this case is, for example, an average value m for a certain fixed period (t1-t2) or a standard deviation σ1. From m, a certain value or more may be set as a threshold value, or a standard deviation σ1 or more may be set as a threshold value. However, the number of times of mastication per time that is important for mastication evaluation cannot be counted only by uniaxial acceleration information. Further, when there is a movement of the head of the measurement subject, the acceleration values of the axes X, Y, and Z of the triaxial acceleration sensor 2 fluctuate greatly as shown in FIG. Therefore, it is difficult to apply the above threshold value determination method.

  Therefore, in this embodiment, in order to determine the threshold value without being affected by the number of mastications per head and the movement of the head, the calculation unit 3 calculates the combined acceleration of each axis X, Y, Z of the acceleration sensor 2. And an acceleration calculation function 3a that makes the base line of the combined acceleration near gravity acceleration 1 [G]. FIG. 3 shows an example of the combined acceleration (b) of the masseter muscle in three axes and the angle (b) of the head obtained by obtaining the cosine of the angle of head movement from the acceleration information of the acceleration sensor 2. The horizontal axis shows time t, the left vertical axis shows acceleration [G], the right vertical axis shows head angle [degree], and a, b, c, and d show acceleration changes due to head movement. Indicates the point in time.

  Then, the calculation unit 3 determines a threshold L2 for detection of mastication based on the value of the base line of the combined acceleration near gravity (1 [G]) as described above, and the combined acceleration value exceeding the threshold L2 is determined. The number of times of chewing, that is, the number of chewing times is counted or the counting function 3b is provided.

  Further, the calculation unit 3 is provided with a mastication strength calculation function 3c for obtaining the mastication strength (mastication force) from the magnitude of each combined acceleration exceeding the threshold L2. Here, the masticatory force F can be obtained as m (mass) × acceleration, but m has individual differences, so the masticatory strength calculation function 3c determines a standard value to determine the masticatory force, and finally the masticatory force during the meal period Find the average value of.

On the other hand, in order to obtain the number of chewing times per mouth, the head angle direction cosine cos ⁻¹ θ = x / √ (x ² + y ² + x ² ) is calculated from the acceleration information of the acceleration sensor 2 so that the head is directed straight forward. In addition to providing a mouthful judgment function 3d for estimating that food is put in the mouth when a change of a predetermined angle (for example, 45 degrees) or more with respect to the angle at which the food is being held is 1 second or longer and the above-mentioned mastication is detected The number of times that the bite judging function 3d has estimated that food has been put into the mouth is counted from the start of measurement of mastication to the end of measurement, and the number of times of mastication is divided by the number of times that food has been put into the mouth at the end of mastication measurement. A mastication frequency calculation function 3e for obtaining a typical mastication frequency

  In addition, when the movement of the head other than the movement of the head that puts food into the mouth (angle change) is detected from the change in the synthetic acceleration, the count value during the period of the movement of the head is measured By performing the process of subtracting the number of chewing times, it is possible to remove noise due to head movement and to measure the exact number of chewing times.

  Thus, the number of mastications counted during measurement is updated and displayed on the display unit 5 under the control of the calculation unit 3, and at the end of the measurement, together with the number of mastications per mouthful and the average mastication strength (mastication force) Is displayed. Then, under the control of the calculation unit 3, the total number of chewing times during the meal, the number of chewing times per mouth, and the average mastication strength data are stored in the data storage unit 4. The display at the end of the measurement is maintained for a certain period of time and then automatically turned off under the control of the calculation unit 3, and the mastication meter 1 enters a standby state. The person to be measured knows the number of mastications and the number of mastications per mouth from this display, so that he / she can recognize the lack of the number of mastications and his / her masticatory power, and the effort to increase the number of mastications in the next meal. It can be used as a guide.

  The history of the data stored in the data storage unit 4 is displayed on the display unit 5 under the control of the calculation unit 6 if the up operation button 92 and the down operation button 93 of the operation unit 6 are operated. Can be made.

  By the way, the acceleration sensor 2 of the present embodiment is provided at the tip of the rod portion 10 which can be expanded and contracted downward from the phone main body 8, but the phone main body 8 is connected to the base of the ear hook 11 as shown in FIG. The rod portion 10 provided integrally therewith may be configured so that its position can be moved from the position of the measurer's ear to the position of the cheek. In this case, the acceleration sensor 2 is built in the phone body 8. Further, as shown in FIG. 4B, the acceleration sensor 2 is built in the phone main body 8 on one side of the arm-type headphones, and is attached to the rod portion 10 ′ that can be expanded and contracted with respect to the arm 12. The position 2 may be movable from the ear position to the cheek position. In the illustrated example, the configuration of the mastication meter 1 other than the acceleration sensor 2 is built in a housing 12 separate from the phone body 8, and the operation buttons 91 of the display unit 5 and the operation unit 6 are provided on the surface of the housing 11. Exposed. Of course, it may be incorporated in the phone body 8. Further, only the acceleration sensor 2 may be moved as in the case of FIG. Note that LN in FIG. 4 is a code for connecting to an audio device when used as a normal head font.

 In addition, if there is an action to put food in the mouth, the composite acceleration obtained from the acceleration information of the acceleration sensor 2 changes abruptly with a magnitude different from that of mastication. A method of estimating that food has been put in the mouth by capturing that the threshold value has been exceeded may be adopted in the bite determination function 3d.

 Furthermore, the acceleration sensor 2 may be used as a sensor for measuring the acceleration of body movement, and may also be used as an activity meter that measures the amount of physical activity from the correlation between the acceleration information and the exercise intensity index. In other words, as a program for the calculation unit 6, a program for performing calculation processing as the mastication meter 1 and a program for performing calculation processing as an activity meter are provided, and data necessary for the activity meter is stored in the data storage unit 4 in advance. In addition, it is possible to switch between using as the mastication meter 1 or using as the activity meter by the operation from the operation unit 6.

  Here, the general activity meter is used by being attached to the waist of the measurement subject. However, when the activity meter is also used as the mastication meter 1, it is attached to the head. Therefore, when the walking speed is measured from the acceleration information at both positions, as shown in FIG. 5A, the standard deviation value of the three-axis acceleration differs depending on the wearing position (waist A, head B). However, the mastication meter 1 is also used as the activity meter by setting the parameters for calculating the activity amount from the standard deviation value so that the calculation of the activity amount equivalent to the waist A can be obtained as shown in FIG. Made it possible to do.

(A) is a circuit block diagram of Embodiment 1, (b) is a side view of the phone body of the headphones incorporating Embodiment 1. FIG. 3 is a diagram illustrating an example of a detected waveform of each axis of the acceleration sensor according to the first embodiment. It is explanatory drawing of the relationship between the change of the synthetic acceleration of the acceleration sensor of Embodiment 1, and a head movement angle change. (A) is a side view of another example of the phone body of the headphone incorporating the first embodiment, and (b) is a perspective view of the headphone incorporating the first embodiment. (A) is a measurement example diagram of walking speed in the difference in attachment position when the first embodiment is also used as an activity meter, and (b) is a parameter in difference in attachment position when the first embodiment is also used as an activity meter. It is an example figure of the calculation result of the active mass for change explanation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mastication meter 2 Acceleration sensor 3 Calculation part 3a Acceleration calculation function 3b Counting function 3c Mastication strength calculation function 3d Mouth judgment function 3e Mastication number calculation function 4 Data storage part 5 Display part 6 Operation part 7 Battery power supply 8 Phone body 91 ... Operation button 10 Rod part 11 Ear hook

Claims (5)

A triaxial acceleration sensor, a mounting unit that presses the acceleration sensor against the cheek of the person to be measured, and a calculation unit are provided. The calculation unit obtains a triaxial combined acceleration from the acceleration detection output of the acceleration sensor. Acceleration calculation function, counting function that counts the number of mastications from the number of times the combined acceleration value exceeds a predetermined threshold, and presumes the action of putting food into the mouth from the movement of the head of the subject detected based on the change in the combined acceleration A mastication meter having a function of counting the number of operations and a function of calculating the number of mastications for each mouth from the number of operations and the counted number of mastications. The mastication meter according to claim 1, wherein the number of times that the synthesis degree acceleration value exceeds a predetermined threshold value during the period of movement of the head is subtracted from the number of mastication times. The mastication meter according to claim 1 or 2, wherein a function of obtaining mastication strength from the combined acceleration value is provided in the calculation unit. The mastication device according to any one of claims 1 to 3, wherein the mounting means is formed in the form of a headphone with an arm or an armless headphone. The mastication according to any one of claims 1 to 4, wherein a mounting portion of the acceleration sensor is extendable and retractable so that the position of the acceleration sensor can be adjusted in a state of being mounted on the measurement subject by the mounting means. Total.

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