METHOD OF ANALYZING BODY COMPOSITION WITH MEASUREMENT OF VOLTAGE SIGNALS AT MULTIPLE POSITIONS OF BODY

• US 20100249642A1
• Filed: 02/08/2010
• Published: 09/30/2010
• Est. Priority Date: 03/24/2009
• Status: Active Grant

• Current Assignee: Biospace
• Original Assignee: Biospace
• Inventors: CHA, KI CHUL
• Granted Patent: US 8,386,028 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
• CPC Class Codes: A61B 5/7257 using Fourier transforms

Abstract

A method of analyzing a composition of a human body having a plurality of body segments is disclosed. The method can include applying a current signal to a body. The method can further include simultaneously measuring a plurality of voltage signals from a plurality of measuring positions of the body during a predetermined period, and processing at least two of the plurality of voltage signals to determine a composition parameter of a body segment so as to assess or analyze composition of the body.

Claims

1. A method of assessing composition of a body comprising a trunk and four extremities attached thereto, the four extremities comprising first, second, third and fourth extremities, the method comprising:

applying a first current signal between the first and second extremities, the first current signal comprising a first frequency component in a first frequency;

applying a second current signal between the third and fourth extremities, the second current signal comprising a second frequency component in a second frequency substantially different from the first frequency;

measuring at least one voltage signal at a distal end portion of each of the four extremities;

processing the at least one voltage signals to obtain a first value indicative of impedance of a first extremity with respect to the first frequency, further processing the at least one voltage signals to obtain a second value indicative of impedance of a second extremity with respect to the second frequency; and

assessing composition of the body using the first and second values, wherein assessing does not use impedance of the first extremity with respect to the second frequency obtainable from processing of the at least one voltage signals.

2. The method of claim 1, wherein assessing does not use impedance of the second extremity with respect to the first frequency obtainable from processing of the at least one voltage signals.

3. The method of claim 1, wherein the first current signal comprises a third frequency component in a third frequency which is substantially different from the first and second frequencies.

4. A method of analyzing composition of a body, the method comprising:

providing a first current signal having a first frequency to a first current path through the body and between a first upper extremity and a first lower extremity;

simultaneously with providing of the first current signal, providing a second current signal having a second frequency distinguishable from the first frequency to a second current path through the body and between a second upper extremity and a second lower extremity;

measuring voltage signals from voltage measuring positions of the four extremities while the first and second current signals are applied, each extremity comprising at least one of the voltage measuring positions;

processing the measured voltage signals to determine a first value representing impedance of a first body segment with respect to the first frequency and a second value representing impedance of a second body segment with respect to the second frequency.

5. The method of claim 4, wherein the first body segment and the second body are the same body segment.

6. The method of claim 4, wherein the first body segment and the second body segment are different body segments.

7. The method of claim 4, wherein each of the first body segment and the second body segment is a segment selected from the group consisting of a trunk and four extremities.

8. The method of claim 4, wherein the first body segment is one of upper extremities, wherein said processing comprises estimating a third value representing impedance of the other upper extremity with respect to the first frequency based on the first value.

9. The method of claim 8, wherein the third value is estimated to be substantially same with the first value.

10. The method of claim 8, wherein said processing comprises assessing composition of the body using the values representing impedance of the body segments.

11. The method of claim 10, wherein the at least one composition parameter comprises at least one selected from the group consisting of percentages of body water, body fat, bone, and muscle.

12. The method of claim 4, wherein said processing comprises:

processing two voltage signals from the plurality of voltage signals to determine a voltage drop signal; and

determining the first value based on the voltage drop signal and the first current signal.

13. The method of claim 4, wherein the first current signal is applied using a first current source, wherein the second current signal is applied using a second current source which is electrically decoupled from the first current source.

14. The method of claim 4, wherein the first current signal represents a single frequency.

15. The method of claim 4, wherein said applying the at least one current signal comprises generating a modulated signal.

16. The method of claim 15, wherein said modulated signal is generated using a phase-shifting keying (PSK) modulation scheme.

17. The method of claim 4, wherein the first current signal is a combined signal of two or more sinusoidal signals and represents two or more superimposed frequencies, wherein one of the two or more sinusoidal signals is a harmonic of another sinusoidal signal.