Method for measuring the degree of edema and apparatus using the same

• US 20010020138A1
• Filed: 01/16/2001
• Published: 09/06/2001
• Est. Priority Date: 01/21/2000
• Status: Active Grant

• Current Assignee: Tanita Corporation (Tanita)
• Original Assignee: Tanita Corporation (Tanita)
• Inventors: Ishigooka, Maki, Fukuda, Yoshinori
• Granted Patent: US 6,714,813 B2
• Time in Patent Office: Days
• US Class Current: 600/547
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/4869 Determining body composition

Abstract

Disclosed is an edema measuring method comprising the steps of: putting at least two pairs of electrodes on different locations selected in the body; making an alternating current to flow in the body via one pair of electrodes; measuring voltage appearing between the other pair of electrodes; calculating impedance on the basis of the supplied alternating current and the measured voltage; and calculating an index value representing the degree of edema on the basis of the impedance. Also, an apparatus using the method is disclosed.

Claims

1. A method for measuring the degree of edema of a person characterized in that it comprises the steps of:

putting at least two pairs of electrodes on different locations selected in the body of the person;

supplying alternating current to one pair of electrodes;

measuring voltage appearing between the other pair of electrodes;

calculating impedance on the basis of the supplied alternating current and the measured voltage; and

calculating an index value representing the degree of edema on the basis of the impedance.

2. A method according to

claim 1

wherein:

said alternating current includes a plurality of alternating current components of different frequencies, which are supplied one after another to said one pair of electrodes;

voltage appearing between said the other pair of electrodes is measured every time when an alternating current component of selected frequency is supplied;

the impedance value is calculated on the basis of each alternating current component and corresponding voltage;

and the index value of edema is calculated on the basis of the so calculated impedance values.

3. A method according to

claim 2

wherein the index value of edema is a ratio of intra-cellular water to extra-cellular water or inversely, or a ratio of extra-cellular water to total body water or inversely.

4. A method according to

claim 1

wherein:

an alternating current of single frequency is supplied to said one pair of electrodes; and

the index value of edema is calculated on the basis of the phase difference between the alternating current and the voltage, and the resistance value calculated from the alternating current and the voltage.

5. An apparatus which is capable of measuring the degree of edema of a person characterized in that it comprises:

at least two pairs of electrodes to be put on selected locations in the body of the person;

an alternating current supplying device which supplies alternating current to one pair of electrodes;

a voltage measuring device which measures the voltage appearing between the other pair of electrodes; and

an arithmetic unit which calculates impedance on the basis of the supplied alternating current and the determined voltage, and calculates an index value representing the degree of edema on the basis of the so calculated impedance.

6. An apparatus according to

claim 5

wherein:

the alternating current supplying device supplies a plurality of alternating currents of different frequencies to said one pair of electrodes; and

the voltage measuring device measures the voltage appearing between said the other pair of electrodes every time when an alternating current of selected frequency is supplied, allowing the arithmetic unit to calculate the impedance values on the basis of each alternating current and corresponding voltage and to calculate the index value of edema on the basis of the so calculated impedance values.

7. An apparatus according to

claim 6

wherein the index value of edema is a ratio of intra-cellular water to extra-cellular water or inversely, or a ratio of extra-cellular water to total body water or inversely.

8. An apparatus according to

claim 5

wherein it further comprises a phase difference measuring device which measures the phase difference between the supplied alternating current and the measured voltage, whereby the arithmetic device may calculate the index value of edema on the basis of the phase difference and the resistance value calculated from the alternating current and the voltage provided that an alternating current of single frequency is supplied to said one pair of electrodes.

9. An apparatus according to any of

claims 5

to

8

wherein it further comprises an estimating device which determines what stage of edema the person has from the calculated index value of edema and other relevant data to be referred to.

10. An apparatus according to

claim 9

wherein said estimating device further determines whether the amount of food has been regulated well from the calculated index value of edema and other relevant data to be referred to.

11. An apparatus according to

claim 9

or

10

wherein said other relevant data is body weight or fat free mass of the person.

12. An apparatus according to any of

claims 5

to

8

wherein it further comprises an estimating device which determines what stage of edema the person has by comparing the calculated index value of edema with a reference value which represents the index value of edema in normal physical condition.

13. An apparatus according to any of

claims 5

to

8

wherein it further comprises an estimating device which determines what stage of edema the person has by comparing the present index value of edema with the average of the index values of edema already calculated.

14. An apparatus according to any of

claims 5

to

13

wherein it further comprises a display which shows the calculated index value of edema and/or the determined stage of edema the person has.

15. An apparatus according to

claim 14

wherein said display shows a series of index values of edema already calculated, representing how the index value of edema has been varied.

16. An apparatus according to

claim 15

wherein said display shows 10 to 15 averages of index values of edema, each average representing the average of the index values calculated in each of 10 to 15 equi-divisions into which the length of time spanning from the outset to the latest measurement is divided.

17. An apparatus according to any of

claims 5

to

16

wherein it further comprises a communication device which transmits to other data processors at least one sort of information selected among measured voltage, measured phase difference, some derivations therefrom, calculated index value of edema, determined stage of edema the person has, and personal particulars.

18. An apparatus according to

claim 17

wherein said communication device receives the results of a given process executed on said information in said other data processors.

19. An apparatus according to any of

claims 5

to

18

wherein it further comprises a writing device which writes one sort of information selected among measured voltage, measured phase difference, some derivations therefrom, calculated index value of edema, determined stage of edema the person has, and personal particulars.