BIOSIGNAL MEASUREMENT APPARATUS AND BIOSIGNAL MEASUREMENT METHOD

• US 20140309540A1
• Filed: 06/24/2014
• Published: 10/16/2014
• Est. Priority Date: 07/06/2012
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: MORIKAWA, Koji, OZAWA, Jun
• Granted Patent: US 10,292,600 B2
• Time in Patent Office: Days
• US Class Current: 600/484
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/0826 Detecting or evaluating apnoea events A61B5/4818 takes precedence
• CPC Class Codes: A61B 5/25 Bioelectric electrodes therefor
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/364 Detecting abnormal ECG interval, e.g. extrasystoles, ectopic heartbeats
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/6804 Garments; Clothes

Abstract

A biosignal measurement apparatus includes: a potential difference measurement unit that measures a potential difference between a plurality of electrodes of an electrode unit placed on a user'"'"'s chest; an ECG analysis unit that obtains an electrocardiogram (ECG) indicating a temporal variation of a cardiac potential of the user, from the potential difference measured by the potential difference measurement unit; an impedance measurement switching unit that determines a start timing of a first period which is a period not including an R wave, using the ECG obtained by the ECG analysis unit; an impedance measurement unit that measures an impedance between the plurality of electrodes in the first period; and a respiratory calculation unit that calculates respiratory information related to respiration of the user, based on a temporal variation of the impedance measured by the impedance measurement unit.

Claims

1. A biosignal measurement apparatus comprising:

a potential difference measurement unit configured to measure a potential difference between a plurality of electrodes placed on a user'"'"'s chest;

an ECG obtainment unit configured to obtain an electrocardiogram (ECG) indicating a temporal variation of a cardiac potential of the user, from the potential difference measured by the potential difference measurement unit;

an impedance measurement switching unit configured to determine a start timing of a first period which is a period not including an R wave, using the ECG obtained by the ECG obtainment unit;

an impedance measurement unit configured to measure an impedance between the plurality of electrodes in the first period; and

a respiratory calculation unit configured to calculate respiratory information related to respiration of the user, based on a temporal variation of the impedance measured by the impedance measurement unit.

2. The biosignal measurement apparatus according to claim 1,

wherein the ECG obtainment unit is configured to obtain the ECG of the user, from the potential difference measured by the potential difference measurement unit in a second period which is a period including the R wave in the ECG and different from the first period.

3. The biosignal measurement apparatus according to claim 1,

wherein the ECG obtainment unit is further configured to calculate a heart rate based on a time interval between two adjacent R waves in the ECG, and output the calculated heart rate.

4. The biosignal measurement apparatus according to claim 1,

wherein the impedance measurement switching unit is configured to determine the start timing of the first period to be when a predetermined time elapses based on the R wave in the ECG obtained by the ECG obtainment unit.

5. The biosignal measurement apparatus according to claim 1,

wherein the impedance measurement switching unit is configured to determine the start timing of the first period to be when a predetermined time elapses from a most recent time at which the R wave appears in the ECG.

6. The biosignal measurement apparatus according to claim 2,

wherein the ECG obtainment unit is configured to obtain the ECG including a part in which the first period and the second period alternate, and

the respiratory calculation unit is configured to:

obtain the temporal variation of the impedance between the plurality of electrodes, by temporally interpolating the impedance in the second period between the impedance measured in the first period preceding the second period and the impedance measured in the first period following the second period; and

calculate the respiratory information based on a peak of a low frequency component of the obtained temporal variation of the impedance.

7. The biosignal measurement apparatus according to claim 1,

wherein the impedance measurement switching unit is further configured to determine a length of the first period, based on a time interval between two adjacent R waves in the ECG obtained by the ECG obtainment unit.

8. The biosignal measurement apparatus according to claim 7,

wherein the impedance measurement switching unit is configured to receive a first time at which the R wave is detected most recently, and determine the length of the first period to cause the first period to be included between the first time and a time at which the time interval between the two adjacent R waves elapses from the first time.

9. The biosignal measurement apparatus according to claim 1, further comprising

a current application unit configured to start applying a current between the plurality of electrodes, at the start timing determined by the impedance measurement switching unit,

wherein the impedance measurement unit is configured to measure the impedance between the plurality of electrodes in the first period, based on the potential difference between the plurality of electrodes and a magnitude of the current applied by the current application unit.

10. The biosignal measurement apparatus according to claim 6,

wherein the respiratory calculation unit is configured to:

calculate a plurality of respiratory information candidates by performing the temporal interpolation according to a plurality of different methods;

select, from the plurality of respiratory information candidates, a respiratory information candidate indicating a higher respiratory rate when a heart rate calculated by the ECG obtainment unit is higher; and

output the selected respiratory information candidate as the respiratory information.

11. The biosignal measurement apparatus according to claim 6,

wherein the respiratory calculation unit is configured to:

calculate a plurality of respiratory information candidates by performing the temporal interpolation according to a plurality of different methods;

select, from the plurality of respiratory information candidates, a respiratory information candidate indicating a lower respiratory rate when an amplitude of the temporal variation of the impedance measured by the impedance measurement unit is higher; and

output the selected respiratory information candidate as the respiratory information.

12. The biosignal measurement apparatus according to claim 1,

wherein the impedance measurement switching unit is further configured to determine a start timing and a length of a preliminary measurement period which is a period for continuously measuring the cardiac potential of the user,

the ECG obtainment unit is configured to obtain the temporal variation of the cardiac potential of the user in the preliminary measurement period, from the potential difference measured by the potential difference measurement unit in the preliminary measurement period, and

the impedance measurement switching unit is configured to determine the start timing and a length of the first period, based on the temporal variation of the cardiac potential of the user in the preliminary measurement period.

13. The biosignal measurement apparatus according to claim 12,

wherein the ECG obtainment unit is further configured to detect an abnormality of a P wave or an ST wave, based on the obtained temporal variation of the cardiac potential of the user in the preliminary measurement period, and

the impedance measurement switching unit is configured to determine the start timing and the length of the first period, to cause the P wave or the ST wave having the abnormality detected by the ECG obtainment unit and the R wave to be included in the second period.

14. A biosignal measurement method comprising:

measuring a potential difference between a plurality of electrodes placed on a user'"'"'s chest;

obtaining an electrocardiogram (ECG) indicating a temporal variation of a cardiac potential of the user, from the measured potential difference;

determining a start timing of a first period which is a period not including an R wave, using the obtained ECG;

measuring an impedance between the plurality of electrodes in the first period; and

calculating respiratory information related to respiration of the user, based on a temporal variation of the measured impedance.

15. A non-transitory computer-readable recording medium for use in a computer, the recording medium having a computer program recorded thereon for causing the computer to execute the biosignal measurement method according to claim 14.