JP2001204707A - Electrical characteristic-measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrical characteristic-measuring instrument capable of precise measurement by easily operating a conductive clip to be connected to an electrode stuck to the body of a subject and assuring conduction of the instrument to the electrode. SOLUTION: This electrical characteristic-measuring instrument supplies a measurement signal Ia into the body B of the subject through surface electrodes Hc and Lc conductively fitted to surface spots at prescribed two separated places of the body B of the subject to measure the current value of the signal Ia, and measures a voltage Vp generated between the prescribed surface spots of the body B of the subject through surface electrodes Hp and Lp conductively fitted to surface spots at prescribed two separated different places of the body B of the subject to measure a biological electric impedance. The instrument is provided with the conductive clip 20 to be connected to the electrode 2 (electrodes Hc, Hp, Lc, Lp) of an electrode 10 fitted to the body B of the subject and the clip 20 has two holding parts 24 expanded and opened nearly simultaneously.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrical characteristic measuring device useful for estimating the state of body fat and the distribution of body water of a subject based on the bioelectrical impedance method, and more particularly, to an apparatus for measuring the electrical characteristics of a subject. The present invention relates to a conductive clip for connecting an electrode and a device.

[0002]

2. Description of the Related Art The present inventor has applied for an apparatus using an M-sequence signal as a bioelectrical impedance measuring apparatus (Japanese Patent Laid-Open No. 10-14898). In that invention, 4
By performing a Fourier transform on the signal converted at the terminal A / D, bioelectric impedance at many frequencies is measured to calculate information on the amount of water inside and outside the cell.

[0003] The configuration of the invention described above will be described below. In recent years, to evaluate the body composition of humans and animals,
Research on the electrical properties of living organisms has been conducted. The electrical properties of living organisms vary significantly depending on the type of tissue or organ. For example, in humans, the electrical resistivity of blood is 150
While it is around Ω · cm, the electrical resistivity of bone and fat is 1 to 5 kΩ · cm. The electrical characteristics of the living body are called bioelectric impedance, and are measured by passing a small current between a plurality of electrodes attached to the body surface of the living body. The method of estimating the body water distribution, body fat percentage, body fat mass, etc. of the subject from the bioelectric impedance obtained in this way is called the bioelectric impedance method ("Bioelectric impedance method as a method for evaluating body composition", Baumga
rtner, RN, etc. Author, "Bioelectric impedance and its clinical application", Medical electronics and biotechnology, Hiroshi Kanai, 20 (3)
Jun 1982, "Estimation of body limb water distribution by impedance method and its application", Medical Electronics and Biotechnology, Makoto Haeno et al., 23 (6) 1985, "Long-term measurement of urinary bladder volume by impedance method" Ergonomics, written by Yasuo Kuchinomachi, 28 (3) 1992, etc.).

[0004] Bioelectric impedance is derived from the resistance of a living body to the current carried by ions in the body (resistance) and the reactance associated with various types of polarization processes created by cell membranes, tissue interfaces, or non-ionized tissue. Be composed. Capacitance, which is the reciprocal of reactance, causes a time delay in current rather than voltage, and creates a phase shift (phase shift). This value is the arctangent of the ratio of reactance to resistance (arctangent). It can be determined geometrically as a phase angle.

The bioelectric impedance Z, the resistance R, the reactance X and the electric phase angle φ depend on the frequency. At very low frequencies f _L , the bioelectrical impedance Z at the cell membrane-tissue interface is too high to conduct electricity. Thus, electricity flows only through the extracellular fluid and the measured bioelectrical impedance Z is purely a resistance R.

Next, as the frequency increases, the current penetrates the cell membrane, the reactance X increases, and the phase angle φ increases. The magnitude of the bioelectrical impedance Z is equal to the value of the vector defined by Z ² = R ² + X ² . The frequency at which both the reactance X and the phase angle φ are maximized is called a critical frequency f _C, and is one electrical characteristic value of a living body that is a conductive conductor. Above this critical frequency f _C , the cell membrane-tissue interface loses its capacitive capacity, and the reactance X decreases accordingly. At very high frequencies f _H , the bioelectrical impedance Z is again purely equivalent to the resistance R.

FIG. 9 is an electrical equivalent circuit diagram (equivalent circuit model) of the human body. In this figure, Cm represents the cell membrane capacity, and Ri and Re represent the intracellular fluid resistance and the extracellular fluid resistance, respectively. At low frequencies f _L , the current is mainly flowing in the extracellular space, and the impedance Z is equal to the extracellular fluid resistance Re. At high frequencies f _H , the current passes through the cell membrane completely, which is equivalent to the cell membrane capacitance Cm being substantially short-circuited.
Therefore, impedance Z at high frequency f _H is
It is equal to the combined resistance Ri · Re / (Ri + Re).

According to the method described above, the intracellular fluid resistance R
i and the extracellular fluid resistance Re can be determined, and based on these, the body fat status and body water distribution (intracellular fluid volume, extracellular fluid volume, etc.) of the subject such as body fat percentage, fat weight, lean body mass, etc. Volume and the total body water content).
The change in the body water distribution can be estimated from the change in the resistances Re and Ri. As a bioelectrical impedance measuring device that performs measurement / estimation of each of these parameters by injecting a small sine wave current of a plurality of frequencies arbitrarily selected into a living body and digitally processing the obtained signal, there is a special table. Hei 6
The thing described in 506854 is known.

In the conventional device described in the above publication, in addition to the complexity of the device configuration, minute sine-wave currents of a plurality of arbitrarily selected frequencies are injected into the living body at predetermined intervals, and the obtained signal is output. Processing takes a few seconds to complete all measurements. Therefore, there is a drawback that it is easily affected by breathing, pulse, etc. for the following reasons.

First, the effect of respiration will be described. As described above, it is known that the resistivity of fat is extremely large, but the electric impedance of air is also extremely large.
In addition, the bioelectric impedance is measured by flowing a small current between a plurality of electrodes mounted on the body surface of the human body as described above, and the electrodes are usually attached to the right hand and the right foot of the subject, respectively. Therefore, the current flows from the right arm to the upper right body to the lower right body to the right foot, and passes through the upper right body (right lung), which contains a lot of air. Further, the bioelectrical impedance is affected by the cell membrane capacitance Cm (see FIG. 9), and this capacitance Cm changes due to respiration.

The bioelectrical impedance is related to hemodynamics, metabolic capacity, and the like, and is also closely related to blood flow. That is, the blood flow of the body is a part of the amount of water in the body, and changes according to expansion and contraction of the heart. On the other hand, bioelectric impedance changes according to the amount of water in the body. Therefore, the bioelectrical impedance must be measured in consideration of the blood flow that changes according to the expansion and contraction of the heart. However, in the above-described bioelectric impedance measuring apparatus, although there is a close relationship between the bioelectric impedance and the blood flow, the measurement is not performed in consideration of the blood flow, so that the apparatus is affected by the pulse. .

In order to reduce the influence of the pulse and respiration, it is conceivable to measure the bioelectric impedance continuously for a longer period than the pulse or respiration cycle. However, if current is continuously applied to the human body for a long time (for example, 1 second or more),
May cause harm to human body. That is, when a sine wave signal is used, there has been a problem that accurate bioelectric impedance, body fat amount, and body water amount cannot be measured.

In order to solve the above problems, it is necessary to measure the bioelectrical impedance in a very short time without being affected by a pulse or breathing. Instead, it is conceivable to use an impulse-like minute current containing many frequency components. However, in this method, for an extremely short time (for example, 0.1 μm).
In order to concentrate electric energy for about 2 sec., not only a circuit that generates a high voltage is required, but also a very large amount of energy is injected into the human body even in an extremely short time, so that there is no damage or burns. Depending on the danger of life, it is not practical.

Therefore, according to the present invention, M
A probe current consisting of a sequence code signal is passed, the flowing current and the voltage between the electrodes are detected, each of them is Fourier-transformed and converted into a voltage value for each frequency, and the bioelectrical impedance between the parts of the living body based on the conversion result. Are calculated and displayed. Usually, a living body is provided with four electrodes in order to allow a probe current to flow through the living body and detect a flowing current and a voltage between the electrodes. Usually, a coaxial cable is used as a cable for connecting these four electrodes to the device, and a conductive clip is connected to the end of the coaxial cable. In this conductive clip, two adjacent electrodes are simultaneously held by one conductive clip, and the electrode and the cable are connected, and the four electrodes and the device can be connected by the two conductive clips.

[0015]

As described above, the conductive clip of the electrical characteristic measuring device having the above-described structure has a structure as described above.
Hold the two electrodes at the same time, connect the electrodes and the cable,
The conductive clip itself has two expandable hold portions for being held by the electrodes. Then, when the two holding portions are expanded by pressing the knob of the conductive clip, there is a problem that the two electrodes are not simultaneously opened due to the strength of the spring or the like, and it is difficult to sandwich the two electrodes at the same time. Further, there is also a problem that the opening amount is not the same and the holding state is not stable because the holding state is not stable, and the conduction state between the two electrodes and the electrode portion of the conductive clip is difficult to stabilize.

The present invention has been made in view of such a problem, and an object of the present invention is to expand the two holding portions substantially simultaneously by pressing the grip portion of the conductive clip to open the two holding portions. It is an object of the present invention to provide an electrical characteristic measuring device provided with a conductive clip which can be opened and easily hold two electrodes, has a stable holding state, and reliably conducts.

[0017]

In order to achieve the above object,
The electrical characteristic measuring device according to the present invention measures a voltage value generated between predetermined surface portions of a subject's body using two electrodes conductively attached to two adjacent surface portions of the subject's body. Thus, the electrical characteristic measuring device for calculating the bioelectrical impedance, the electrical characteristic measuring device includes a conductive clip having two holding parts that simultaneously hold the two adjacent electrodes, the two holding parts are substantially It is characterized by expanding simultaneously.

In a preferred specific embodiment of the electrical characteristic measuring apparatus according to the present invention, the conductive clip includes two sandwiching members, each of which has two arm portions, The four electrodes are held by the two holding portions formed by the two arm portions. Further, as another preferable specific specific aspect of the electric property measuring device according to the present invention, the conductive clip includes a main body, and two sandwiching pieces that are swingably supported by the main body, and the holding unit includes , The body and 2
The two sandwiching pieces are formed between the two sandwiching pieces, and the two sandwiching pieces are interlocked and expanded by an interlocking tooth portion.

In the electric characteristic measuring apparatus of the present invention thus configured, when the conductive clip is connected to the electrode adhered to the body of the subject with the conductive gel, the two holding portions can be opened almost simultaneously. Therefore, the contact pieces of the two electrodes of the electrode sheet can be easily inserted into the two holding portions, and the electrodes can be easily held by the conductive clips. Further, since the holding state is stable, the connection between the electrode and the cable is stable, and the electrical characteristics of the body of the subject can be accurately measured.

By configuring the conductive clip so as to include the two sandwiching members, the holding can be performed easily and the configuration of the conductive clip can be simplified. By configuring the conductive clip to include the main body and two sandwiching pieces that are swingably supported by the main body, the electrode portions of the main body are in a parallel state, and the holding state between the contact piece of the electrode sheet and the electrode portion is improved. The measurement is stable, the conduction state of both is stable, and accurate measurement is possible.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the electrical characteristic measuring apparatus according to the present invention will be described in detail with reference to the drawings. FIG.
1 is a block diagram showing an electrical configuration of an embodiment in which the present invention is used in a bioelectrical impedance measuring device, and FIG. 2 is a schematic diagram schematically showing a use state of the device. Figures 1 and 2
In the bioelectrical impedance measuring device 1 of this example,
00 sends the probe current Ia as a measurement signal to the keyboard 1 and the body B of the subject,
A measurement processing unit 2 for digitally processing voltage and current information obtained from the apparatus, and various physical quantities related to bioelectric impedance, body fat, and body water distribution of the human body based on the processing results of the measurement processing unit 2 while controlling each unit of the device. (Central processing unit) 3 for calculating
Display unit 4 for displaying the bioelectric impedance, body fat mass, body water mass, etc. of the body B of the subject calculated by the above, and a ROM 5 for storing the processing program of the CPU 3
And various data (for example, height, weight, gender,
It roughly comprises a data area for temporarily storing the amount of extracellular fluid and intracellular fluid, etc.) and a RAM 6 in which a work area of the CPU 3 is set.

The keyboard 1 is used by a measurer to input a measurement start switch for instructing a start of measurement, a human body characteristic item such as height, weight, gender and age of the subject, and to measure a total measurement time T and a measurement interval t. The operation data of various keys supplied from the keyboard 1 is converted into key codes by a key code generation circuit (not shown),
Supplied to

The measurement processing unit 2 is attached to a PIO (parallel interface) 71, a measurement signal generator 72, a low-pass filter (hereinafter, referred to as LPF) 73, a coupling capacitor 74, and a predetermined part of the body. An output processing circuit including a surface electrode Hc; and surface electrodes Hp, Lp, and L that are also attached to a predetermined part of the body.
c, coupling capacitors 80a, 80b, 90, differential amplifier 81, I / V converter (current / voltage converter) 9
1. L consisting of an analog anti-aliasing filter
The input processing circuit includes PFs 82 and 92, A / D converters 83 and 93, and sampling memories (ring buffers) 84 and 94.

In the measurement processing section 2, the measurement signal generator 7
2 is equal to or more than 10 kΩ over the entire signal frequency range in which the output resistance is generated, and every time a signal generation instruction signal is supplied from the CPU 3 via the PIO 71 at a predetermined cycle t during the entire measurement time T, The longest linear code (maximal li
LPF7 that repeatedly generates the probe current Ia of the (near codes) series (M series) a predetermined number of times and uses the generated probe current Ia as a measurement signal to remove high-frequency noise.
3 and a coupling capacitor 74 that removes the DC component from flowing to the subject's body B so as not to flow to the surface electrode Hc.

The value of the probe current Ia is, for example, 500
８００800 μA. The supply period of the signal generation instruction signal matches the measurement interval t set by the measurer using the keyboard 1. Further, in this example, the number of repetitions of the probe current (measurement signal) Ia is 1 to 256 per signal generation instruction signal. The number of repetitions may be set arbitrarily by the measurer using the keyboard 1.
The number of repetitions increases as the number of repetitions increases. However, although it is a minute current, it may adversely affect the human body when continuously applied to the human body for a long time. Therefore, the number of repetitions is preferably 1 to 256.

As described in the section of "Prior Art", a small time interval (0.1
μsec), the energy is concentrated
The probe current using the series signal disperses the energy in about 1 msec even though it contains many frequency components, so it does not injure the living body and occurs at a time interval sufficiently shorter than the pulse or respiration cycle. So they are not affected. Furthermore, for example, in the case of a rectangular wave signal with a duty of 50%, the amplitude of the frequency spectrum is large at low frequencies and small at high frequencies, so that the S / N frequency characteristic deteriorates in the high frequency region, whereas the M sequence signal is Since the amplitude of the frequency spectrum is substantially flat over the entire frequency range, the S / N frequency characteristic is also substantially flat. The details of the M-sequence signal are described in R. C.
Dixon, "Spread Spectrum Communication System" (P56-P89)
Please refer to.

As shown in FIG. 2, the surface electrode Hc is conductively attached to the right back part H of the subject at the time of measurement by an adhesive method. Therefore, the measurement signal (probe current)
Ia enters body B from the right hand part of the subject. The coupling capacitor 74 and the surface electrode Hc are connected by a coaxial cable 7a, and the shield of the coaxial cable 7a is grounded.

As shown in FIG. 2, the surface electrode Hc (first electrode) is conductively attached to the right back part H of the subject at the time of measurement by an adhesive method, and the surface electrode Lc (second electrode) is used. Is conductively attached to the right instep L by an adhesive method, and the measurement signal (probe current) Ia enters the body B from the right hand part of the subject. The surface electrode Hp (third electrode)
Electrode) is electrically conductively attached to the right back H of the subject by an adhesive method, and the surface electrode Lp (fourth electrode)
Is conductively attached to the right instep L by an adhesive method. At this time, the surface electrodes Hc and Lc are
It is attached to a part farther from the center of the human body than p and Lp.

Here, an adhesive system in which the surface electrode is conductively attached to the back part H and the back part L of the subject will be described in detail with reference to FIGS. FIG. 3A is a perspective view of the upper surface side in a state where the conductive gel of the electrode sheet is separated,
4B is a perspective view of the lower surface, FIG. 4A is a front view of the conductive clip, FIG. 4B is a front view of the expanded state, FIG. 4C is a bottom view of FIG. FIG. 5A is a cross-sectional view taken along the line AA, FIG. 5 is a schematic perspective view of the conductive clip of FIG. 4 in a state where two sandwiching members are disassembled, and FIG. It is a perspective view of the state before connecting by a conductive clip. The electrode sheet 10 is attached to the back H and the back L of the subject.

As shown in FIG. 3, the electrode sheet 10 is made of a plastic sheet of polyethylene terephthalate or the like having a thickness of 50 μm or more, and contacts 11 are formed at the center by cutting. Folded upward. The electrode sheet 10 has electrodes 12, 12 formed on the lower surface at both ends in the longitudinal direction.
It extends to 1,11. Then, conductive gels 13 having adhesiveness are attached to the lower surfaces of the electrodes 12. The conductive gels 13 contain a NaCl solution in order to obtain electrical conduction. Electrodes 12, 12
Is formed, for example, by printing a conductive paste.

The contact pieces 11, 11 of the above-mentioned electrode sheet 10
As shown in FIGS. 4 and 5, the conductive clip 20 connected to the terminal has two holding portions that are simultaneously held between two adjacent electrodes 12 among the four electrodes 12 attached to the subject's body. And the two holding parts can be simultaneously opened. That is, the conductive clip 20 is composed of two sandwiching members 21 and 21 made of plastic, and a spring 2 for urging the sandwiching members 21 and 21 in a closing direction.
2 and a center shaft 23 for connecting the sandwiching members 21 and 21. The two sandwiching members 21 and 21 have the same shape with a thin center joint. Two sandwich members 21 and 2
1 is an outer arm portion 21a which is two arm portions each
And an inner arm portion 21b. The outer arm portion 21a and the inner arm portion 21b oppose each other.
One holding unit 24 is configured. Hold part 2
The electrode portions 25, 25 are located on the inner arm portion 21b of 4 in opposition to the outer arm portion 21a, and cables 26, 26 are connected to these electrode portions.

The electrode portions 25, 25 are formed of a conductor which is hardly deteriorated. In this embodiment, the electrode portions 25, 25 are formed of a stainless steel plate or a wire having a diameter of about 1.5 mm, and are connected to the cables 26, 26 by, for example, soldering. Have been. The electrode portions 25, 25 may be formed of a non-plated metal plate or the like as a conductor that is hardly deteriorated. For example, by using only a plate material such as silver, even if the conductive gel 13 of the electrode sheet 10 adheres, the plating is peeled off, the conduction state becomes unstable, and the contact resistance value does not change. Alternatively, the electrode portion may be formed of a plastic containing a conductive material such as carbon, and may be injection-molded integrally with the sandwiching member 21 by two-color molding.

As shown in FIG. 6, the electrode sheet 10 is adhered to the back part H and the back part L by conductive gels 13, 13, and the electrodes 12, 12 are connected to the back part H and the back part L. It becomes conductive. Hold the contact pieces 11, 11
4, 24, and sandwiching member 21 of conductive clip 20,
21, the electrode portions 25, 25 and the contact piece 1.
Electrical continuity is established between the cables 26, 26 and the back part H and foot part L. In FIG. 6A, the electrode 12 on the hand side corresponds to the surface electrode Hc, the cable 26 (7a) is connected, and the electrode 1 in the center direction of the body B is connected.
2 corresponds to the surface electrode Hp, to which the cable 26 (7b) is connected. In FIG. 6B, the electrode 1 on the toe side
2 corresponds to the surface electrode Lc, the cable 26 (7d) is connected, and the electrode 12 in the center direction of the body B corresponds to the surface electrode Lp, and the cable 26 (7c) is connected.

The conductive clip (first conductive clip) 20 of the back part H has two electrode portions 25 that simultaneously hold the adjacent first and third electrodes and connect to these electrodes. , The conductive clip (second conductive clip) 20 of the instep L has two electrode portions 25 that simultaneously hold the adjacent second and fourth electrodes and connect to these electrodes. By connecting and holding the conductive clips 20, 20 to the two electrode sheets 10, 10, conduction between the four surface electrodes and the cable 26 can be established.

The differential amplifier 81 shown in FIG. 1 detects a potential (potential difference) between two surface electrodes Hp (third electrode) and Lp (fourth electrode). That is, the differential amplifier 81
When the probe current Ia is applied to the body B of the subject,
The voltage Vp between the right limb and the right hand of the subject is detected and input to the LPF 82. This voltage Vp is a voltage drop between the surface electrode Hp and the surface electrode Lp due to the bioelectric impedance of the body B of the subject.

The LPF 82 removes high frequency noise from the voltage Vp and supplies it to the A / D converter 83. LPF
The cutoff frequency 82 is lower than half the sampling frequency of the A / D converter 83. Thereby, aliasing noise generated in the A / D conversion processing by the A / D converter 83 is removed. The A / D converter 83 converts the noise-removed voltage Vp into a digital signal at a predetermined sampling cycle every time the digital conversion signal Sd is supplied from the CPU 3, and converts the digitized voltage Vp to the sampling cycle. The data is supplied to the sampling memory 84 every time.

As shown in FIG. 2, the surface electrode Lc is adhered to the right instep L of the subject by an adhesive method, and the surface electrode Lc and the coupling capacitor 90 (see FIG. 1) are coaxial. They are connected by a cable 7d, and the shield of the coaxial cable 7d is grounded. The I / V converter 91 detects a current flowing between the two surface electrodes Hc and Lc and converts the current into a voltage. That is, the I / V converter 91
When the probe current Ia is applied to the body B of the subject,
Detecting a probe current Ia flowing between the right limb of the subject,
After being converted to the voltage Vc, it is supplied to the LPF 92.

The LPF 92 removes high-frequency noise from the input voltage Vc and supplies it to the A / D converter 93.
The cutoff frequency of the LPF 92 is lower than half the sampling frequency of the A / D converter 93. In this case, A /
The aliasing noise generated in the A / D conversion processing by the D converter 93 is removed. The A / D converter 93 converts the noise-removed voltage Vc into a digital signal at a predetermined sampling cycle every time the digital conversion signal Sd is supplied from the CPU 3, and converts the digitized voltage Vc into a sampling cycle. The data is supplied to the sampling memory 94 every time.

The CPU 3 starts the measurement by the measurement processing unit 2 according to the processing program stored in the ROM 5, and detects the detection voltage V at a predetermined sampling cycle.
After sampling p and Vc a predetermined number of times, control for stopping measurement and the following processing are performed. That is, CP
U3 first reads out the voltages Vp and Vc, which are functions of time, stored in the sampling memories 84 and 94 sequentially, and performs the Fourier transform processing on the voltages Vp (f) and Vc (f) (which are functions of frequency. After converting to f), averaging is performed to calculate bioelectric impedance Z (f) ｛= Vp (f) / Vc (f)｝ for each frequency.

Next, based on the obtained bioelectric impedance Z (f) for each frequency, the CPU 3 obtains an impedance locus D as shown in FIG. From the obtained impedance locus D, the bioelectric impedance R0 of the body B of the subject at a frequency of 0 and the bioelectric impedance R at a frequency of infinity are obtained.
∞ is calculated, and from the calculation result, the intracellular fluid resistance and the extracellular fluid resistance of the body B of the subject are calculated.

In the column of "Prior Art", cells in a human body tissue are represented by a simple electric equivalent circuit (see FIG. 9), but in an actual human body tissue, cells of various sizes are irregular. , An electrical equivalent circuit close to the actual one is shown in FIG.
Is represented by a distributed constant circuit in which elements connected in series with a capacitor and a resistor having a time constant τ = Cmk · Rik (Re is extracellular fluid resistance, Rik is intracellular fluid of each cell) The resistance, Cmk, is the cell membrane capacity of each cell). Therefore,
In this embodiment, since an intracellular fluid resistance and an extracellular fluid resistance are determined by using an electrical equivalent circuit (see FIG. 8) that is close to actual, the impedance locus D of the human body is shown in FIG. Thus, the center is an arc raised above the real axis.

Next, the calculated intracellular fluid resistance and extracellular fluid resistance, and the height of the subject input from the keyboard 1,
Based on human body characteristic data such as weight, gender and age,
By making full use of the body composition estimation formula incorporated in the processing program in advance, the body fat percentage, fat weight,
The amount of lean body mass, the amount of intracellular fluid, the amount of extracellular fluid, and the sum of these amounts of body water (body fluid) are calculated. And
Each of the calculated data is displayed on a display unit 4 including a display controller and a display (for example, an LCD).

The operation of the thus-configured electrical characteristic measuring apparatus of the present embodiment will be described below. First, prior to the measurement, as shown in FIG. 2, two surface electrodes Hc,
The electrode sheet 10 having Hp is placed on the right back part H of the subject.
An electrode sheet 10 having two surface electrodes Lp and Lc
To the right instep L of the subject, the conductive gel 13,
13 using an adhesive method. At this time, the electrode sheet 10 is attached such that the longitudinal direction of the electrode sheet 10 is directed to the hands and feet. Thus, the electrode on the tip of the back part H corresponds to the surface electrode Hc, and the electrode on the center side of the body B corresponds to the surface electrode Hp. The electrode at the toe of the instep portion L corresponds to the surface electrode Lc, and the electrode on the center side of the body B corresponds to the surface electrode Lp.

Next, the electrode sheet 10 and the bioelectrical impedance measuring device 100 are connected by the conductive clip 20. The holding portions 24, 24 are expanded by pressing the grip portions of the holding members 21, 21 of the conductive clip 20, and inserted so that the contact pieces 11, 11 of the electrode sheet 10 are positioned in the holding portions. When the pressing of the pressing member 21 is released, the holding portions 24 and 24 are closed, and the electrode portion 25 and the electrode 12 of the contact piece 11 are brought into a conductive state.
Is held. Since the electrode portion 25 is formed of a conductor that is hardly deteriorated, the conductive gels 13 and 1 of the electrode sheet 10 are formed.
Even if the NaCl solution of No. 3 adheres, it does not rust or deteriorate. In addition, the conductive clip 20 is connected to the left and right
The contact pieces 11 of the electrode sheet 10 can be easily inserted since the four and 24 are evenly and substantially simultaneously expanded, and the holding and fixing is ensured, so that the conduction between the electrode portion 25 and the electrode 12 of the contact piece 11 is also improved. Stabilize.

The measurer (or the subject himself) uses the keyboard 1 of the bioelectrical impedance measuring device 100 to
The human body characteristic items such as the height, weight, sex, and age of the subject are input, and the total measurement time T from the start of measurement to the end of measurement, the measurement interval t, and the like are set. Data and setting values input from the keyboard 1 are stored in the RAM 6.

Next, when the measurer (or the subject) turns on the measurement start switch of the keyboard 1, the CPU 3
Sends a signal generation instruction signal to the measurement signal generator 72 of the measurement processing unit 2 after performing a predetermined initial setting. As a result, the measurement signal generator 72 repeatedly generates the M-sequence probe current Ia a predetermined number of times, and outputs LP as the measurement signal.
F73, coupling capacitor 74, coaxial cable 7
a to the surface electrode Hc (see FIG. 2) affixed to the back H of the subject through a.
The measurement signal Ia of A flows through the body B of the subject from the surface electrode Hc, and the first measurement is started.

When the measurement signal Ia is applied to the body B of the subject, the voltage Vp generated between the right limb to which the surface electrodes Hp and Lp are attached in the differential amplifier 81 of the measurement processing unit 2
Is supplied to the A / D converter 83 via the LPF 82. On the other hand, in the I / V converter 91, the surface electrode H
After the probe current Ia flowing between the right limb to which c and Lc are attached is detected and converted to the voltage Vc, the LPF 9
The signal is supplied to the A / D converter 93 through the second line. At this time, C
The PU 3 outputs an A / D converter 8 every sampling period.
The digital conversion signal Sd is supplied to 3,93.

The A / D converter 83 converts the voltage Vp into a digital signal every time the digital conversion signal Sd is supplied, and supplies the digital signal to the sampling memory 84. The sampling memory 84 sequentially stores the digitized voltage Vp. On the other hand, the A / D converter 93 converts the voltage Vc into a digital signal each time the digital converted signal Sd is supplied, and supplies the digital signal to the sampling memory 94. The sampling memory 94 sequentially stores the digitized voltage Vc.

The CPU 3 calculates the probe current (measurement signal) I
When the number of repetitions of “a” reaches a preset number, after performing control to stop the measurement, first, the voltages Vp, which are stored in the sampling memories 84 and 94 and are a function of time, as a function of time.
The voltages Vp (f) and Vc (f), which are functions of frequency, are sequentially read out and subjected to Fourier transform processing.
(F is a frequency), and after averaging, the bioelectrical impedance Z (f) ｛= Vp (f) /
Vc (f)} is calculated.

Next, the CPU 3 performs curve fitting based on the calculated bioelectrical impedance Z (f) for each frequency by a calculation method of the least squares method, and obtains an impedance locus D as shown in FIG. From the obtained impedance locus D, the body B of the subject
Of the bioelectric impedance R0 at the frequency 0 and the bioelectric impedance R∞ at the frequency of infinity (corresponding to the X coordinate value of the point where the arc of the impedance locus D intersects the X axis). Then, the intracellular fluid resistance and extracellular fluid resistance of the body B are calculated.

The CPU 3 executes a processing program in advance based on the calculated intracellular fluid resistance and extracellular fluid resistance, and human body characteristic data such as the height, weight, sex, and age of the subject input from the keyboard 1. The body fat percentage, fat weight, lean body mass, intracellular fluid volume, extracellular fluid volume, and the sum of these body water ( Volume). Then, the calculated data are stored in the RAM 6 and displayed on the display unit 4.

Next, the CPU 3 determines whether or not the entire measurement time T has elapsed. If it is determined that the measurement time T has elapsed, the CPU 3 terminates the subsequent measurement processing. After waiting for the time t corresponding to to elapse, the same measurement processing is started again. Then, the above process is repeated until the entire measurement time T has elapsed.

As described above, according to the configuration of this example, the probe current Ia is dispersed in energy of about 1 msec despite including many frequency components, and
Since the amplitude of the frequency spectrum uses an M-sequence signal that is almost flat over the entire frequency range, it does not damage the living body and removes the effects of respiration and pulse in the measurement of body fat status and body water distribution. It is possible,
Good S / N measurement over the entire frequency range is possible. Further, the measurement signal can be generated only from the shift register and the plurality of logic circuits, so that the configuration becomes very simple.

Further, since the bioelectric impedance at the infinite frequency can be obtained by using the curve fitting method based on the least square method, the influence of stray capacitance and extraneous noise can be avoided. The extracellular fluid resistance and the intracellular fluid resistance can be determined. Further, the surface electrodes Hc, Hp, Lp, Lc and the circuit elements 73,
Between the coupling capacitors 74 and 8.
Since the components 0a, 80b, and 90 are interposed, the DC component of the current flowing into the living body or the current flowing in the living body can be cut, which is safe for both the living body and the device.

Further, the output resistance of the measurement signal generator 72 is 10 kΩ over the entire range of the signal frequency.
At the same time, since the coupling capacitor 74 is interposed between the LPF 73 and the surface electrode Hc, the surface electrode Hc can be substantially regarded as a constant current source, and the probe current is determined by the bioelectric impedance (about 1 kΩ). I
The current value of a does not change, the maximum value of the current flowing through the living body is determined, and the living body is safe. Therefore, it is possible to more accurately and safely estimate the state of the body fat and the distribution of the body water of the subject.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. This embodiment is different from the above-described embodiment in the conductive clip, and other configurations are substantially the same. 10A is a front view of the conductive clip, FIG. 10B is a front view of a state where the holding portion of the conductive clip is expanded, FIG. 10C is a cross-sectional view taken along line BB of FIG.
(D) is a schematic perspective view of the conductive clip. In FIG. 10, a conductive clip 30 includes a main body 31, a shaft 32 on the main body,
A pair of pinches 33, 33 pivotally supported by 32;
A spring 34 for urging the holding piece toward the body 31;
The sandwiching piece can swing in an interlocking manner by the interlocking teeth 35 that mesh with each other. Then, the main body 31 and the sandwiching piece 3
Hold portions 36, 36 are formed between the holding portions 36, 33.
Electrodes 37, 37 are located on the main body 31 at portions facing the sandwiching pieces, and these electrodes protrude slightly from the main body 31 and are located in parallel. Depressions are formed in the sandwiching pieces 33, 33 corresponding to the electrode portions, so that contact with the contact pieces 11, 11 can be stabilized. The cable 3 is connected to the electrode portions 37
8, 38 are connected.

The thus constructed conductive clip 30
When the sandwiching pieces 33, 33 are swung by pressing the knob at the lower end against the spring 34, the sandwiching pieces 33, 3
3 are simultaneously and evenly swung substantially simultaneously by the interlocking teeth portion 35, and the two holding portions 3 between the main body 31 and the sandwiching pieces 33, 33 are provided.
6 and 36 have the same opening amount. For this reason, coupled with the fact that the electrode portions are positioned in parallel, the holding portions 36, 3
6, it is easy to insert the contact pieces 11, 11 of the electrode sheet 10,
The connection between the electrode sheet 10 and the conductive clip 30 can be easily performed. In addition, since the two holding portions 36 and 36 have the same opening amount, the conductive clip 30 is securely held by the electrode sheet 10 and the conduction between the electrode portion 37 and the electrode 12 of the contact piece 11 is also stabilized. Then, the electrical characteristics of the subject can be accurately measured. The interlocking teeth 35 have a gear ratio of 1: 1.
In that case, the pinching pieces 33, 33 do not have the same amount of swinging and expand almost simultaneously.

Another embodiment of the present invention will be described with reference to FIG. FIG. 11 is a front view of a state in which the holding portion of the conductive clip is expanded. This embodiment is characterized in that the electrodes and cables are changed from the embodiment shown in FIGS.
Other configurations are substantially equivalent. The conductive clip 40 is composed of two holding members 4 made of an insulator such as plastic.
1, 42, a spring 43 for urging the sandwiching members 41, 42 in the closing direction, and a central shaft 44 connecting the sandwiching members 41, 42.

The two sandwiching members 41 and 42 have outer arms 41a and 42a and inner arms 41b and 42b, which are two arms, respectively. Then, two holding portions 45, 45 are configured by the outer arm portion and the inner arm portion that face each other. In this example, two electrode portions 46 and 47 are provided on one sandwiching member 41, and a cable 48 connected to these electrodes protrudes from a knob at the lower end of the sandwiching member 41. For this reason, the cable 48 can be routed with only one pinching member, which has an effect of being easy.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific structure is not limited to these embodiments, and the design of the present invention is within the scope of the present invention. Modifications are included in the present invention. For example,
Although the bioelectrical impedance measuring device and the electrode attached to the body are connected by a coaxial cable, they may be connected by using a normal conducting wire. FIG.
The electrode portion 25 of the conductive clip 20 shown in FIG. 10 may be configured to slightly protrude like the electrode portion 37 of the conductive clip 30 shown in FIG. 10, and a recess may be provided on the opposite side.

[0061]

As can be understood from the above description, the electric characteristic measuring apparatus of the present invention has two holding portions for simultaneously holding two adjacent electrodes among the four electrodes attached to the body of the subject. Since there are two conductive clips and the two holding parts can be opened at the same time, it can be easily connected to the electrode sheet attached to the back and foot of the human body, and the connection state is stable and accurate. Measurement becomes possible.

Further, by configuring the conductive clip to include two sandwiching members, the number of parts is small and the configuration can be simplified. Further, the main body and the two sandwiching pieces are constituted, and the two sandwiching pieces are interlocked by the interlocking teeth, so that the electrode portions of the main body are parallel to each other, so that the connection can be easily performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment in which the present invention is applied to a bioelectrical impedance measuring device.

FIG. 2 is a diagram schematically showing a state of use of the bioelectrical impedance measuring device shown in FIG.

FIG. 3A is a perspective view of an upper surface side in a state where a conductive gel of an electrode sheet is separated, and FIG. 3B is a perspective view of a lower surface side.

4A is a front view of a conductive clip, FIG. 4B is a front view of an expanded state, FIG. 4C is a bottom view of FIG. 4A, and FIG. 4D is a cross section taken along line AA of FIG. FIG.

FIG. 5 is a schematic perspective view of a state where two sandwiching members of the conductive clip of FIG. 4 are disassembled.

FIG. 6 is a perspective view of a state before an electrode sheet is attached to a back part H and a back part L and connected by a conductive clip;

FIG. 7 is a diagram showing an impedance locus of a human body.

FIG. 8 is a close-to-actual electrical equivalent circuit diagram of cells in a tissue of a human body.

FIG. 9 is a simplified electrical equivalent circuit diagram of cells in a tissue.

10A and 10B show another embodiment of the present invention, wherein FIG. 10A is a front view of a conductive clip, FIG. 10B is a front view of the conductive clip in an expanded state, and FIG. B sectional view,
(D) is a schematic perspective view of the conductive clip.

FIG. 11 is a front view of a conductive clip according to still another embodiment of the present invention, in which a holding portion of a conductive clip is expanded.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Keyboard (human-body-characteristic data input means) 3 CPU (arithmetic means) 4 Display part (output means) 10 Electrode sheet 11 Contact piece 12 Electrode 13 Conductive gel 20, 30, 40 Conductive clips 21, 41, 42 Nipping member 21a, 21b, 41a, 41b, 42a, 42b
Arm part 24, 36, 45 Hold part 25, 37, 46, 47 Electrode part 31 Main body 33 Clipping piece 35 Interlocking tooth part 72 Measurement signal generator (part of measurement signal supply means) 72a Modulator (of measurement signal supply means) 73 LPF (part of measurement signal supply unit) 81 Differential amplifier (part of voltage measurement unit) 82 LPF (part of voltage measurement unit) 83 A / D converter (part of voltage measurement unit) 84, 94 Sampling memory (storage means) 91 I / V converter (part of current measuring means) 92 LPF (part of current measuring means) 100 Bioelectric impedance measuring device Hc, Hp, Lc, Lp Surface electrode (No. 1st to 4th electrodes)

Claims (3)

[Claims] 1. A method for measuring a voltage value generated between predetermined surface portions of a subject's body by using two electrodes conductively attached to two adjacent surface portions of the subject's body,
An electrical characteristic measuring device for calculating bioelectrical impedance, the electrical characteristic measuring device comprising a conductive clip having two hold portions for simultaneously holding the two adjacent electrodes, and the two hold portions being substantially simultaneously. An electrical characteristic measuring device characterized by expanding. 2. The clip comprises two clamping members, each of the clamping members having two arm portions,
2. The electrical characteristic measuring device according to claim 1, wherein the four electrodes are held by the two holding portions formed by the two arm portions. 3. The conductive clip includes a main body, and two holding pieces that are swingably supported by the main body, wherein the holding portion is formed between the main body and the two holding pieces, 2. The electrical characteristic measuring apparatus according to claim 1, wherein the two interleaving pieces are interlocked and expanded by the interlocking teeth.