Bioelectrical impedance measuring apparatus

• US 20050054944A1
• Filed: 08/12/2004
• Published: 03/10/2005
• Est. Priority Date: 09/05/2003
• Status: Active Grant

• Current Assignee: Tanita Corporation (Tanita)
• Original Assignee: Tanita Corporation (Tanita)
• Inventors: Oguma, Koji, Nakada, Masato
• Granted Patent: US 7,313,435 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

Abstract

There is provided an apparatus capable of carrying out an accurate bioelectrical impedance measurement by determining whether contact of a living body with electrodes used at the time of the bioelectrical impedance measurement is normal or not more accurately. The apparatus uses a parameter associated with a phase difference in determining the contact condition of the living body with the electrodes. As the parameter associated with a phase difference, the apparatus uses a value represented by X/R wherein R is a resistance component in a bioelectrical impedance to be measured and X is a reactance component in the bioelectrical impedance and determines that contact of the living body with the electrodes is not normal when the value of X/R is out of a determination range such as a<X/R<b (a and b are real numbers).

Claims

1. A bioelectrical impedance measuring apparatus comprising:

an impedance measurement unit for measuring a bioelectrical impedance which comprises electrodes to contact with a living body, and

a determination unit for determining the contact condition of a living body with the electrodes by use of a parameter associated with the phase difference of the living body.

2. The apparatus of claim 1, wherein when the resistance component in a bioelectrical impedance to be measured in the impedance measurement unit is represented by R and the reactance component in the bioelectrical impedance is represented by X, the parameter associated with the phase difference of the living body is a value represented by X/R.

3. The apparatus of claim 2, wherein the condition for determination of the contact in the determination unit is a<

X/R<

b (a and b are real numbers).

4. The apparatus of claim 3, wherein prior to determination of the contact condition of the living body with the electrodes by use of the parameter associated with the phase difference, the determination unit determines the contact condition by determining whether a parameter associated with the resistance component of the bioelectrical impedance to be measured in the impedance measurement unit is a positive value.

5. The apparatus of claim 4, wherein the parameter associated with the resistance component is a true impedance component variable representing the resistance component of a true impedance.

6. The apparatus of claim 4, wherein the parameter associated with the resistance component is a voltage variable based on the resistance component.