JP2001321350A - Electric characteristic measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To present the electric characteristic of every portion of a subject as the ratio to weight measured by bioelectric impedance method. SOLUTION: This electric characteristic measuring device comprises a measurement signal generator 72 or the like for generating a measurement signal; an I/V converter 92 or the like for measuring the current carried in the input of the generated measurement signal to a prescribed portion of the subject; a differential amplifier 81 for measuring the potential difference generated between prescribed portions of the subject; a CPU 3 for calculating the bioelectric impedance of every portion from the current value measured by the I/V converter 91 or the like and the voltage value measured by the differential amplifier 81, and calculating the ratio of at least one of fat weight, fat-free weight, moisture volume, intracellular fluid volume, and extracellular fluid volume to body weight on the basis of the calculated bioelectric impedance, and a display part 4 for displaying the ratio calculated by the CPU 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric characteristic measuring apparatus, and more particularly to an electric characteristic measuring apparatus for measuring various electric characteristics of each part of a subject based on a bioelectrical impedance method.

[0002]

2. Description of the Related Art The inventor of the present invention has previously applied for an apparatus using an M-sequence signal as a bioelectrical impedance measuring apparatus (Japanese Patent Laid-Open No. 10-14898). In the invention, by performing a Fourier transform on the four-terminal A / D-converted signal, bioelectric impedance at many frequencies is measured to calculate information on the water content inside and outside the cell. Although not described in the specification, this apparatus outputs an M-sequence signal many times and performs synchronous addition of each signal in order to improve the SN ratio of the signal.

[0003] The prior art will be described below. 2. Description of the Related Art In recent years, research on the electrical characteristics of living organisms has been conducted for the purpose of evaluating the body composition of humans and animals. The electrical properties of living organisms vary significantly depending on the type of tissue or organ, for example,
In the case of humans, the electrical resistivity of blood is around 150 Ω · cm, whereas the electrical resistivity of bone and fat is 1 to 5 kΩ · cm.
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", Baumgartner, RN, et
c., "Bioelectric impedance and its clinical application", Medical Electronics and Biotechnology, Hiroshi Kanai, 20 (3) Jun 1982, "Estimation of Water Distribution in Limbs by Impedance Method and Its Application", Medical Electronics and Biotechnology, Makoto Haeno, 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 . Reactance X and phase angle φ
Is the critical frequency f _C at which both become maximum,
It is one electrical characteristic value of a living body that is a conductive conductor. Beyond 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. 7 is an electrical equivalent circuit diagram (equivalent circuit model) of the human body. In this figure, Cmk represents the cell membrane capacity, and Rik 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 completely through the cell membrane and the cell membrane capacitance Cm is substantially equivalent to a short circuit. Accordingly, the impedance at high frequency f _H Z
Is the combined resistance Ri · Re / (Ri + Re), (1 / Ri =
Σ1 / Rik).

According to the method described above, the intracellular fluid resistance R
i and the extracellular fluid resistance Re can be obtained, and based on these, the fat weight, lean body mass, etc. of the subject can be estimated, and changes in body water distribution can be estimated by changes in these resistances Re, Ri. Can be estimated. As a bioelectrical impedance measuring apparatus for performing measurement / estimation of each parameter as described above, a small sine wave current of a plurality of frequencies arbitrarily selected is applied to a living body, and the obtained signal is processed by digital signal processing.
The one described in JP-A-6-506854 is known.

[0009]

SUMMARY OF THE INVENTION Among the electrical characteristic values,
The body fat percentage for each part in each part such as the arm and the torso is FAT (n), where fat weight at each part is FAT (n) (n corresponds to each part) and fat-free weight is FFM (n). / (FF
M (n) + FAT (n)) and was presented to the subject.

The contents of the presentation are displayed as 30% for the arm, 20% for the torso, 20% for the legs, 21% for the total, etc.
+ 20 + 20)% ”and“ total 21% ”do not match, so that not only is the presentation content unrealistic,
It was difficult to have accurate recognition.

An object of the present invention is to provide an electric characteristic output device capable of outputting various electric characteristics for each part based on a bioelectrical impedance method by using parameters that allow a subject to easily recognize a health condition. Is to do. Another object of the present invention is to provide an electric characteristic output device capable of displaying various electric characteristics for each part in a display format in which a subject can easily recognize a health condition based on a bioelectric impedance method. is there.

[0012]

An electric characteristic measuring apparatus according to the present invention comprises a signal generating means for generating a measuring signal, and a current measuring means for measuring a current flowing when the generated measuring signal is applied to a predetermined part of a subject. And, voltage measuring means for measuring a potential difference generated between predetermined parts of the subject, and a bioelectric impedance for each part from the current value measured by the current measuring means and the voltage value measured by the voltage measuring means. Calculating means for calculating a ratio of at least one of fat weight, lean mass, water content, intracellular fluid moisture content, and extracellular fluid moisture content to body weight based on the calculated bioelectric impedance And display means for displaying the ratio calculated by the calculation means.

The calculating means calculates a relative value of the ratio in a predetermined population, and displays the relative value on the display means, so that the subject can obtain a fat weight, a lean body mass of a predetermined part or a whole body. It is possible to recognize where the weight, water content, intracellular fluid water content, and extracellular fluid water content are located in the population.

In another aspect, an electric characteristic measuring apparatus according to the present invention comprises: signal generating means for generating a measurement signal; and current measuring means for measuring a current flowing when the generated measurement signal is applied to a predetermined part of a subject. A voltage measuring means for measuring a potential difference generated between predetermined parts of the subject, and a bioelectric impedance for each part calculated from a current value measured by the current measuring means and a voltage value measured by the voltage measuring means. Then, based on the calculated bioelectrical impedance, calculating means for calculating the fat weight and fat free mass for each part, and a human body model corresponding to the fat weight and fat free weight for each part calculated by the calculating means. Display means for displaying.

[0015] Further, the arithmetic means displays a standard human body model corresponding to the human body model on the display means, so that the subject can roughly compare with the standard model.

[0016]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an electrical configuration of an electrical characteristic measuring device according to an embodiment of the present invention.

The electrical characteristic measuring apparatus of the present invention calculates the bioelectrical impedance (hereinafter, referred to as site-specific impedance) at a predetermined site such as an arm or a torso, and obtains fat weight, lean mass, water content, extracellular fluid. It is for estimating electric characteristic values such as a water content and an intracellular fluid water content, and outputting a ratio between the estimated electric characteristic value and body weight.

In particular, the electrical characteristic measuring apparatus according to the present embodiment collects fat weight, and fat weight FAT (n) for each region.
(N corresponds to each part) and the ratio of the subject's weight W (hereinafter, referred to as part-specific fat weight to body weight ratio) are output.

This electric characteristic measuring apparatus comprises a keyboard 1
The probe current Ia is sent as a measurement signal to the body B of the subject, and the measurement processing unit 2 for digitally processing the voltage / current information obtained from the body B of the subject, and the various units of the apparatus are controlled. Based on the processing result of
CPU for calculating physical quantities such as subject-specific impedance, site-specific fat weight, site-specific fat weight to body weight ratio, etc.
(Central processing unit) 3, a display unit 4 for displaying electrical characteristic values such as a fat-to-weight ratio for each part calculated by the CPU 3, a ROM 6 storing a processing program of the CPU 3, and various data ( For example, a data area for temporarily storing the height and weight of the subject, gender, amount of extracellular fluid and intracellular fluid, and a work area of the CPU 3 are set.
AM5.

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

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 portion of the body B of the subject. An output processing circuit including electrodes Hc to be applied, and electrodes Hp, Lp, and L also attached to predetermined portions of the body B of the subject.
c, coupling capacitors 80a, 80b, 90, differential amplifier 81, I / V converter (current / voltage converter) 9
1. L composed 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 that the output resistance is 10 kΩ or more over the entire range of the generated signal frequency, and every time the signal generation instruction signal is supplied from the CPU 3 via the PIO 71 at the 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 for removing a DC component from flowing to the body B of the subject so as not to flow to the electrode Hc. The coupling capacitor 74 and the electrode Hc are connected by a measurement cable (not shown) which is a double shielded wire.

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 arbitrarily set 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.

Here, the M-sequence signal will be described. The M-sequence signal is a code signal generally used in a spread-spectrum communication system or a spread-spectrum ranging system, and is the longest code sequence generated by a shift register or a delay element having a certain length. Say. A binary M-sequence generator that generates an M-sequence signal having a length of (2n-1) bits (n is a positive integer) shifts a logical combination of an n-stage shift register and the n-stage state. And a logic circuit (exclusive logic circuit) that feeds back to the input of the register. M at a certain sample time (clock time)
The output of the sequence generator and the state of each stage is a function of the output of the feedback stage at the immediately preceding sample time. In this embodiment, an M-sequence generator having eight stages (n = 8) of shift registers is used. Further, the frequency of the shift clock of the shift register is set to 2 MHz.

When an impulse signal is used, energy concentrates in a short time interval (0.1 μsec), whereas a probe current using an M-sequence signal includes many frequency components, Since the energy is dispersed to about 1 msec, it does not damage the living body, and occurs at a time interval sufficiently shorter than the pulse or respiratory cycle. Absent. 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,
Since the frequency characteristic of the SN ratio deteriorates in the high frequency region because it is small at high frequencies, the M-sequence signal has a substantially flat frequency characteristic of the SN ratio because the amplitude of the frequency spectrum is substantially flat over the entire frequency region. is there. Note that M
For details of the sequence signal, see “Spread Spectrum Communication System” by RCDixon (p56 to p89).

Here, the concept of measuring the impedance for each part of the electrical characteristic measuring apparatus according to the present embodiment will be described with reference to FIGS. FIG. 2 is a diagram illustrating an impedance model of the body of the subject, which is considered in using the electrical property measurement device according to the present embodiment.

In the present embodiment, the body B of the subject is
m, mn, torso mo, and feet op, oq. Each of the electrodes Hc, Hp, Lp and Lc (see FIG. 1)
Attached to a predetermined site in order to measure each of the bioelectrical impedances (impedance for each site) Z1 to Z5 at each of these sites. In FIG. 2, for convenience of explanation, the impedances Z1 to Z5 for each part are shown only by resistance components.

Each of the electrodes Hp, Lp, Hc, Lc is connected to the electrical characteristic measuring device 100 by a measuring cable (not shown). Next, a description will be given of the position where each electrode is attached when measuring the impedance for each part. FIG.
FIG. 4 is a diagram for explaining the position of an electrode attached when the electrical property measuring device according to the present embodiment is used.

3 (A) to 3 (E) show the impedance model shown in FIG. 2, and FIGS. 3 (A) to 3 (E) respectively measure the impedance Z1 to Z5 for each part. This is to explain the position of the electrode when performing. Each electrode is electrically conductively attached to a predetermined position on the body by an adhesive method.

In FIG. 3A, the symbol I indicates that the probe current Ia is supplied between the site-specific impedances Z1 and Z2. This means that, for example, the electrode Hc is attached to the arm position 1 and the electrode Lc is attached to the arm position n shown in FIG.

The symbol V represents the impedance Z for each part.
1, indicating that the potential difference between Z5 and Z3 is measured. This indicates that, for example, the electrode Hp is attached to the arm position 1 shown in FIG. 2 and the electrode Lp is attached to the foot position p shown in FIG. At this time, the electrode Hp is attached to the inside of the body (heart side) relative to the electrode Hc.

In FIG. 3B, symbol I indicates that the probe current Ia is supplied between the impedances Z1 and Z2 for each part. This means that, for example, the electrode Hc is attached to the arm position 1 and the electrode Lc is attached to the arm position n shown in FIG.

The symbol V represents the impedance Z for each part.
2, the potential difference between Z5 and Z4 is measured. This means that, for example, the electrode Hp is attached to the arm position n and the electrode Lp is attached to the foot position q shown in FIG. At this time, the electrode Hp is attached to the inside of the body (heart side) relative to the electrode Lc.

In FIG. 3C, the symbol I indicates that the probe current Ia is supplied between the site-specific impedances Z3 and Z4. This indicates that, for example, the electrode Hc is attached to the foot position p shown in FIG. 2 and the electrode Lc is attached to the foot position q.

The symbol V represents the impedance Z for each part.
1, indicating that the potential difference between Z5 and Z3 is measured. This indicates that, for example, the electrode Hp is attached to the arm position 1 shown in FIG. 2 and the electrode Lp is attached to the foot position p shown in FIG. At this time, the electrode Lp is the electrode H
It is attached to the inside of the body (heart side) than c.

In FIG. 3D, the symbol I indicates that the probe current Ia is supplied between the site-specific impedances Z3 and Z4. This indicates that, for example, the electrode Hc is attached to the foot position p shown in FIG. 2 and the electrode Lc is attached to the foot position q.

The symbol V represents the impedance Z for each part.
2, the potential difference between Z5 and Z4 is measured. This means that, for example, the electrode Hp is attached to the arm position n and the electrode Lp is attached to the foot position q shown in FIG. At this time, the electrode Lp is the electrode L
It is attached to the inside of the body (heart side) than c.

In FIG. 3E, the symbol I represents the probe current Ia between the impedances Z2, Z5 and Z4 for each part.
Is supplied. This means that, for example, the electrode Hc is attached to the arm position n and the electrode Lc is attached to the foot position q shown in FIG.

The symbol V represents the impedance Z for each part.
1, indicating that the potential difference between Z5 and Z3 is measured. This indicates that, for example, the electrode Hp is attached to the arm position 1 shown in FIG. 2 and the electrode Lp is attached to the foot position p shown in FIG.

Based on the electrode arrangements shown in FIGS. 3A to 3E, a voltage Vp is detected by a differential amplifier 81 described later, and a voltage Vc is detected by an I / V converter 91. You.
Based on these voltage ratios, impedance Z
1 to Z5 are calculated.

Returning to FIG. 1, the differential amplifier 81 detects the potential (potential difference) between the electrodes Hp and Lp according to the electrode arrangement shown in FIG. That is, when the probe current Ia is applied to the body B of the subject, the differential amplifier 81 detects the voltage Vp between predetermined portions of the subject and inputs the voltage Vp to the LPF. This voltage Vp is a voltage drop between the electrode Hp and the electrode Lp due to the impedance of each part 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.

Each time the digital conversion signal Sd is supplied from the CPU 3, the A / D converter 83 converts the noise-free voltage Vp into a digital signal at a predetermined sampling cycle, and converts the digitized voltage Vp Is supplied to the sampling memory 84 every sampling period. The electrode Lc and the coupling capacitor 90 are connected by a measurement cable (not shown) which is a double shielded wire.

The I / V converter 91 detects a current flowing between the electrodes Hc and Lc and converts it into a voltage according to the electrode arrangement shown in FIG. That is, when the probe current Ia is applied to the body B of the subject, the I / V converter 91 detects the probe current Ia flowing between predetermined portions of the subject, and the voltage V
After being converted to c, 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.

Each time the digital conversion signal Sd is supplied from the CPU 3, the A / D converter 93 converts the voltage Vc from which the noise has been removed into a digital signal at a predetermined sampling period, and converts the digitized voltage Vc. Is supplied to the sampling memory 94 every sampling period.

The CPU 3 starts the measurement by the above-described measurement processing unit 2 according to the processing program stored in the ROM 6, and detects the detection voltages Vp and V at a predetermined sampling cycle.
After sampling c for a predetermined number of times, the following processing is performed in addition to the control for stopping the measurement.

That is, first, the CPU 3 sequentially reads out the voltages Vp and Vc, which are functions of time, stored in the sampling memories 84 and 94, and performs the Fourier transform processing on the voltages Vp and Vc, which are functions of frequency. Vc
(F) After conversion into (f is frequency), averaging is performed, and the impedance Z (f) ｛= Vp (f) for each part for each frequency
/ Vc (f)}.

FIG. 4 is a diagram illustrating an impedance locus D drawn by the electrical characteristic measuring device according to the present embodiment. The CPU 3 obtains an impedance locus D as illustrated in FIG. 4 using the least-squares method based on the obtained part-specific impedance Z (f) for each frequency, and obtains the obtained impedance locus. From D, the part-specific impedance R0 of the subject's body B at the frequency 0 and the part-specific impedance R 無限 at the frequency infinity are calculated.
From the calculation results, the intracellular fluid resistance Ri and the extracellular fluid resistance Re of the body B of the subject are calculated.

In an actual human body tissue, cells of various sizes are arranged irregularly. Therefore, an electric equivalent circuit close to the actual one has a series connection of a capacitance and a resistor having a time constant τ = Cmk · Rik. It is represented by a distributed constant circuit in which connection elements are distributed (FIG. 7: Re is extracellular fluid resistance, Rik is intracellular fluid resistance of each cell, Cmk is cell membrane capacity of each cell). Therefore, the impedance locus D of the human body is an arc whose center is higher than the real axis as shown in FIG.

As described above, the CPU 3 calculates the intracellular fluid resistance Ri and the extracellular fluid resistance Re for each site by obtaining the impedance locus D for each site from the impedance for each site for each frequency.

Further, the CPU 3 uses the intracellular fluid resistance Ri and the extracellular fluid resistance Re for each site to calculate the fat weight F per site.
AT (n) (n corresponds to each part) is calculated and divided by the weight W stored in the RAM 5. Thus, the fat-to-weight ratio FAT (n) / W for each region is calculated and displayed on the display unit 4.

Next, the operation of the electrical characteristic measuring apparatus according to the present embodiment will be described. Here, the impedance Z1 for each part in the arm lm of the subject shown in FIG.
Fat weight FAT [arm lm] for each part corresponding to the impedance and fat weight to body weight ratio FAT [arm lm] / W for each part
The case of calculating is described. Prior to the measurement,
As shown in (A), the electrodes Hc and Hp are attached to the position l of the subject's arm, the electrode Lc is attached to the position n of the arm, and the electrode Lp is attached to the position p of the foot by an adhesive method.

Next, the measurer (or the subject himself) uses the keyboard 1 of the electrical characteristic measuring device 100 to input the human body characteristic items such as the height and weight W, gender and age of the subject, and from the start of the measurement. The total measurement time T until the measurement is completed, the measurement interval t, and the like are set. Data and setting values input from the keyboard 1 are stored in the RAM 5.

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 the LPF 73, the coupling capacitor 74,
The electrode H is connected via a measurement cable that is a double shielded wire.
c, the measurement signal Ia of 500 to 800 μA
Flows through the body B of the subject from the electrode Hc, and the first measurement is started.

When the measurement signal Ia is applied to the subject's body B, the differential amplifier 81 of the measurement processing unit 2 outputs the electrode H
The voltage Vp generated between the position l of the arm to which p and Lp are attached and the position p of the foot is detected and supplied to the A / D converter 83 via the LPF 82.

On the other hand, in the I / V converter 91, the electrodes Hc,
After the probe current Ia flowing between the positions l and n of the arm to which Lc is attached is detected and converted into the voltage Vc, the LPF
The signal is supplied to an A / D converter 93 via a line 92. At this time,
From the CPU 3, the A / D converter 8
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 impedance Z1 (f) (= Vp (f) /
Vc (f)) is calculated.

Next, the CPU 3 performs curve fitting by a least-squares method based on the calculated part-specific impedance Z1 (f) for each frequency, and obtains an impedance locus D as illustrated in FIG. From the obtained impedance locus D, the arm l of the subject
and the impedance R0 for each part at the frequency 0 at m
A part-specific impedance R∞ (corresponding to the X-axis coordinate value of a point where the arc of the impedance locus D intersects the X-axis) at an infinite frequency is calculated, and the intracellular fluid resistance Ri in the subject's arm lm is calculated from the calculation result. The extracellular fluid resistance Re is calculated.

After calculating these two values, the CPU 3 calculates
Using the body composition estimation algorithm or the like incorporated in the processing program in advance, the fat weight FAT [arm lm] for each part in the arm lm of the subject is estimated. Next, CPU
3 divides the estimated fat weight FAT [arm lm] for each part by the weight W of the subject input from the keyboard 1 to obtain a fat weight-to-body weight ratio FAT [arm lm] / W for each part. The information is displayed on a display unit 4 including a display (for example, an LCD).

Next, the CPU 3 determines whether or not the total measurement time T has elapsed, and if it is concluded that the measurement time T has elapsed,
The subsequent measurement processing is terminated, and if it has not elapsed, the same measurement processing is started again after waiting for a time t corresponding to the measurement interval to elapse. Then, the above process is repeated until the entire measurement time T has elapsed.

FIG. 5 is a diagram showing a display example of the electric characteristic measuring device according to the present embodiment. The above-described impedance Z1 for each region and the fat-to-weight ratio FAT [arm 1] for each region
Subsequent to the calculation process of m] / W, the display contents illustrated in FIG. 5 are presented to the subject by performing the calculation for each of the site-specific impedances Z2 to Z5.

In this presentation example, “arm 3%, foot 7%, torso 1
5%, whole body 25% ", etc. Since these values indicate the ratio of fat weight to body weight at each site,
The sum of the fat weight to body weight ratio of all parts such as "arm 3%, foot 7%, torso 15%" matches "whole body 25%". Therefore, the subject can recognize the fat weight of each part or the whole body with respect to his / her weight W.

Further, according to the configuration of this example, the probe current Ia disperses in energy of about 1 msec despite including many frequency components, and the amplitude of the frequency spectrum is substantially flat over the entire frequency range. Since the M-sequence signal is used, in the measurement of the state of body fat and the distribution of water in the body, the living body is not damaged, and the influence of respiration and pulse can be removed. Measurement 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 impedance for each part at the infinite frequency can be obtained by using the curve fitting method by the least squares method, the influence of stray capacitance and external noise can be avoided, and the capacitance component of the cell membrane is not included. Pure extracellular fluid resistance Re and intracellular fluid resistance Ri can be determined.
As described above, the embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the specific configuration is not limited to these embodiments, and a design change within a scope not departing from the gist of the present invention. And the like.

First, in the above-described embodiment, the left and right arms, the left and right legs, and the torso are targeted as five parts of the body of the subject. The present invention is not limited to these locations, and it is sufficient that the concept of the electrode arrangement described in FIG. 3 such as the palm can be applied to measure the impedance for each part and calculate the fat-to-weight ratio for each part.

In the above embodiment, the measurement of the impedance for each part and the calculation of the fat-to-weight ratio for each part are individually performed for each part of the impedance. Alternatively, these may be performed continuously. In this case, FIG.
The electrodes Hc, Hp, Lc, and Lp shown in (1) are provided in a number corresponding to the number of sites where the impedance measurement for each site is continuously performed.

For example, when the measurements shown in FIGS. 3A to 3E are continuously performed, the electrode Hc is at the hand positions l and n and the foot position p, and the electrode Lc is at the hand position. Affixed at position n and foot position q. Also, the electrode Hp is at the hand position l, n
In addition, the electrode Lp is attached to the position p, q of the foot. For example, a switch (not shown) is provided between the electrodes Hc, Hp, Lc and Lp and the measurement processing unit 2. This switch switches the same electrode each time based on an instruction from the CPU 3 according to the measurement corresponding to each of FIGS. 3A to 3E.

Thus, for example, at the same time that the impedance Z2 for each part is measured, the fat weight to body weight ratio for each part corresponding to the impedance Z1 for each part can be calculated in parallel. The weight-to-weight ratio can be displayed in real time. Further, in the above-described embodiment, the fat weight to body weight ratio for each part is displayed, but the display result is further used to make a relative value in a predetermined population such as a deviation value (for each part and / or whole body). ) May be displayed.

In this case, the RAM5 or external storage means (not shown) which can be accessed by the CPU 3 stores the fat-to-weight ratio for each part substantially corresponding to the same age, gender, height, weight, etc. as the subject in the population. Is stored as CPU3
Displays the relative value of the fat-to-weight ratio for each part of the subject in the population. Regarding the display of the relative values, the ranking may be presented, for example, “20th in the population 100”, or a distribution function or the like indicating a deviation value or the like is displayed, and the corresponding position of the subject is presented there. May be.

In the above embodiment, the fat weight to body weight ratio for each part is indicated by a numeral, but the fat weight and lean body weight estimated from the impedance for each part, and the height and weight of the subject are used. Then, the actual degree of fat attachment may be schematically displayed by a human body model.

FIG. 6 is a diagram showing another display example of the electric characteristic measuring device according to the present invention. FIG. 6A shows a standard body shape corresponding to the height, weight, age, sex, and the like of the subject, and FIG. 6B shows a human body model of the subject. 6 (A) and 6 (B) are displayed by a region T corresponding to lean mass and a region U corresponding to fat mass.

Referring to FIG. 6 (B), by displaying the human body model, the subject can roughly know the degree of fat attachment at each site. In addition, by displaying the fat weight to body weight ratio by site (see FIG. 5) in addition to the human body model, the subject can specifically recognize how much fat exists in each site by the weight ratio. Further, FIG.
As shown in (A), by displaying the standard body shape corresponding to the subject and the fat-to-weight ratio for each part thereof side by side with FIG. 6 (B), the subject can compare the two body types and obtain a difference from the standard body shape. Can be roughly recognized, and further, by comparing the fat weight to body weight ratio for each part, it is possible to specifically recognize which part has fat on the basis of the body weight ratio as compared with the standard.

In this case, the difference between the area U corresponding to the fat weight shown in FIG. 6A and the area U corresponding to the fat weight shown in FIG. The difference between the fat weight to body weight ratio and the fat weight to body weight ratio shown in FIG. 6B may be displayed. In any case, the subject can roughly recognize the difference from the standard body type. Further, FIGS. 6A and 6B show a human body model (front view) which is a two-dimensional image. Thereby, the subject's body line can be seen from each direction.

In the above-described embodiment, the impedance of each part is measured, and the fat-to-weight ratio of each part is estimated from the impedance based on a predetermined algorithm or the like. Or it was done by printout. As another form, inside or outside a device for measuring electrical characteristics such as bioelectric impedance,
Means (FDD or the like) for storing processing data of the CPU 3 or data related to the subject may be provided. As a result, the processing data of the CPU 3 can be stored in the FD, and a large number of test results at a school or an insurance place can be managed. In addition, by using these test results, statistical processing and the like can be performed in investigation and analysis, which is convenient.

In the above embodiment, bioelectrical impedance, impedance locus, extracellular fluid resistance and intracellular fluid resistance for each region are calculated as bioelectrical parameters to be calculated, and the fat weight to body weight ratio is calculated. I have. As another form, the bioelectrical admittance, the admittance trajectory, the extracellular fluid resistance, and the intracellular fluid resistance for each site may be calculated to calculate the fat-to-body weight ratio for each site.

Further, in the above description, fat weight is taken as an electrical characteristic estimated from the site-specific impedance. However, fat weight, water content, extracellular fluid moisture content, intracellular fluid moisture content, etc. As described above, the concept of the present invention can be applied as long as the output is obtained by dividing the electrical characteristic value estimated using the impedance by the weight of the subject. Also,
The shift register and the logic circuit that constitute the M-sequence generator are as follows:
The hardware configuration is not limited to a software configuration.

[0080]

According to the present invention, since the electric characteristics of each part can be presented in terms of the ratio to the body weight based on the bioelectrical impedance method, the subject can easily recognize these values. Further, as a display format, a specific number relating to the electrical characteristics of each part or a schematic human body model can be output and presented to the subject in a manner that is easy to recognize.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an electrical characteristic measuring device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an impedance model of each part of a body, which is considered in using the electrical property measuring device according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating the position of an electrode attached when using the electrical property measuring device according to the embodiment of the present invention.

FIG. 4 is a diagram exemplifying an impedance locus drawn by the electrical characteristic measuring device according to the embodiment of the present invention.

FIG. 5 is a diagram showing a display example of the electric characteristic measuring device according to the embodiment of the present invention.

FIG. 6 is a diagram showing another display example of the electrical characteristic measuring device according to the present invention.

FIG. 7 is an electrical equivalent circuit diagram (equivalent circuit model) of a human body.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 keyboard 2 measurement processing unit 3 CPU 4 display unit 5 RAM 6 ROM 72 measurement signal generator (part of signal generation unit) 73 LPF (part of signal generation unit) 81 differential amplifier (part of voltage measurement unit) 82 LPF (part of voltage measuring means) 83,93 A / D converter 84,94 Sampling memory 91 I / V converter (part of current measuring means) 92 LPF (part of current measuring means) 100 Electrical characteristics Measurement device Hc, Lc, Hp, Lp Electrode

Claims (4)

[Claims] A signal generating means for generating a measurement signal; a current measuring means for measuring a current flowing when the generated measurement signal is applied to a predetermined portion of the subject; and a potential difference generated between the predetermined portions of the subject. Voltage measuring means to be measured, the bioelectrical impedance for each site is calculated from the current value measured by the current measuring means and the voltage value measured by the voltage measuring means, based on the calculated bioelectrical impedance, Calculating means for calculating a ratio of at least one of fat weight, lean mass, water content, intracellular fluid water content, and extracellular fluid water content to body weight; and displaying the ratio calculated by the calculating means. And a display means. 2. The electrical characteristic measuring device according to claim 1, wherein the calculating means calculates a relative value of the ratio in a predetermined population, and displays the relative value on the display means. 3. A signal generating means for generating a measurement signal, a current measuring means for measuring a current flowing when the generated measurement signal is applied to a predetermined part of the subject, and a potential difference generated between the predetermined parts of the subject. Voltage measuring means to be measured, the bioelectrical impedance for each site is calculated from the current value measured by the current measuring means and the voltage value measured by the voltage measuring means, based on the calculated bioelectrical impedance, It is characterized by comprising calculating means for calculating the fat weight and the fat-free weight for each part, and display means for displaying a human body model corresponding to the fat weight and the fat-free weight for each part calculated by the calculating means. Electrical characteristic measuring device. 4. The electric characteristic measuring apparatus according to claim 3, wherein said calculation means displays a standard human body model corresponding to said human body model on said display means.