Biosignal measurement modules and methods

• US 8,239,009 B2
• Filed: 04/10/2009
• Issued: 08/07/2012
• Est. Priority Date: 12/23/2008
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Lee, Wen-Ching, Ko, Chih-Hsiang, Huang, Tsun-Che
• Primary Examiner(s): Layno, Carl H
• Assistant Examiner(s): PORTER, JR, GARY A
• Application Number:
  US12/421,870
• Publication Number:
  US 20100160793A1
• Time in Patent Office: 1,215 Days
• Field of Search: 600/500, 600/513, 600/526
• US Class Current: 600/513
• CPC Class Codes: A61B 2560/0468 Built-in electrodes
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/14557 specially adapted to extracorporeal circuits
• CPC Class Codes: A61B 5/332 Portable devices specially adapted therefor

Abstract

A biosignal measurement module is provided and includes a biosignal measurement unit, a pose detection unit, and a processing unit. The biosignal measurement unit measures an electrocardiogram signal and a pulse signal of a subject. The pose detection unit detects a position of the biosignal measurement module and outputs position signals. The processing unit receives the electrocardiogram signal, the pulse signal, and the position signals. The processing unit generates a height variation parameter, which indicates the height difference between the position of the biosignal measurement module and a reference position, according to the position signals. The processing unit calculates a current pulse transit time according to the electrocardiogram signal and the pulse signal and compensates for the current pulse transit time according to the height variation parameter to obtain a compensated pulse transit time. The processing unit obtains a blood pressure signal according to the compensated pulse transit time.

Claims

1. A biosignal measurement module comprising:

a biosignal measurement device comprising detection electrodes for measuring an electrocardiogram signal and a photo detector for detecting a pulse signal of a subject;

a pose detector for detecting a position of the biosignal measurement module and outputting a plurality of position signals; and

a processor, coupled to the biosignal measurement device and the pose detector, configured to;

receive the electrocardiogram signal, the pulse signal, and the position signals;

generate a height variation parameter, which indicates the height difference between the position of the biosignal measurement module and a reference position, according to the position signals;

calculate a current pulse transit time according to the electrocardiogram signal and the pulse signal

compensate for the current pulse transit time according to the height variation parameter to obtain a compensated pulse transit time; and

obtain a blood pressure signal according to the compensated pulse transit time.

2. The biosignal measurement module as claimed in claim 1 further comprising a memory for storing an initial diastolic pressure parameter, an initial systolic pressure parameter, an initial pulse transit time, and a relationship constant, wherein the relationship constant relates to the initial systolic pressure parameter and the initial pulse transit time.

3. The biosignal measurement module as claimed in claim 2, wherein the processor is further configured to calculate a systolic pressure value of the blood pressure signal according to the compensated pulse transit time and the relationship constant.

4. The biosignal measurement module as claimed in claim 3, wherein the processor is further configured to calculate the systolic pressure value according an equation SBP_C,=K[PTTc]⁻

1, wherein SBP_C;

represents the systolic pressure value, K represents the relationship constant, and PTT_C represents the compensated pulse transit time.

5. The biosignal measurement module as claimed in claim 4, wherein the relationship constant is obtained by multiplying the initial systolic pressure parameter and the initial pulse transit time.

6. The biosignal measurement module as claimed in claim 3, wherein the processor is further configured to calculate a diastolic pressure value of the blood pressure signal according to the systolic pressure value, the initial systolic pressure parameter, the initial diastolic pressure parameter, the initial pulse transit time, and the compensated pulse transit time.

7. The biosignal measurement module as claimed in claim 6, wherein the processor is further configured to calculate the diastolic pressure value according to an equation

8. The biosignal measurement module as claimed in claim 2, wherein the initial systolic pressure parameter and the initial diastolic pressure parameter stored in the memory are configured to be provided by an external device.

9. The biosignal measurement module as claimed in claim 8, wherein the external device is configured to measure the initial systolic pressure parameter and the initial diastolic pressure parameter, the biosignal measurement device is configured to measure an initial electrocardiogram signal and an initial pulse of the subject, and the processor is further configured to calculate the initial pulse transit time according to the initial electrocardiogram signal and the initial pulse and to calculate the relationship constant according to the initial systolic pressure parameter and the initial pulse transit time.

10. The biosignal measurement module as claimed in claim 9, wherein the processor is further configured to store the calculated initial pulse transit time and the calculated relationship constant into the memory.

11. The biosignal measurement module as claimed in claim 1, wherein the photo detector is combined with one of the detection electrodes.

12. The biosignal measurement module as claimed in claim 1, wherein the biosignal measurement device is configured to measure the electrocardiogram signal and the pulse signal through at least three fingers of the subject.

13. The biosignal measurement module as claimed in claim 1, wherein biosignal measurement module is integrated in a personal digital assistant (PDA), a mobile phone, a digital camera, a global positioning system, or any other portable electronic equipment.

14. The biosignal measurement module as claimed in claim 1, wherein the processor is further configured to compensate for the current pulse transit time according to an equation

15. A biosignal measurement method comprising:

measuring an electrocardiogram signal and a pulse signal of a subject by a biosignal measurement module;

measuring height difference between a position of the biosignal measurement module and a reference position to generate a height variation parameter;

calculating a current pulse transit time according to the electrocardiogram signal and the pulse signal;

compensating for the current pulse transit time according to the height variation parameter to obtain a compensated pulse transit time;

obtaining a blood pressure signal according to the compensated pulse transit time; and

showing the blood pressure signal on a display unit to indicate blood pressure of the subject.

16. The biosignal measurement method as claimed in claim 15 further comprising providing an initial diastolic pressure parameter, an initial systolic pressure parameter, an initial pulse transit time, and a relationship constant, wherein the relationship constant relates to the initial systolic pressure parameter and the initial pulse transit time.

17. The biosignal measurement method as claimed in claim 16, wherein the step of obtaining the blood pressure signal comprises calculating a systolic pressure value of the blood pressure signal according to the compensated pulse transit time and the relationship constant.

18. The biosignal measurement method as claimed in claim 17, wherein the systolic pressure value is calculated according to an equation SBP_C=K[PTT_C]⁻

1, and SBP_C represents the systolic pressure value, PTT_C represents the compensated pulse transit time, K represents the relationship constant which is obtained by K=SBP₀×

PTT₀, SBP₀ represents the initial systolic pressure parameter, and PTT₀ represents the initial pulse transit time.

19. The biosignal measurement method as claimed in claim 17, wherein the step of obtaining the blood pressure signal further comprises calculating a diastolic pressure value of the blood pressure signal according to the systolic pressure value, the initial systolic pressure parameter, the initial diastolic pressure parameter, the initial pulse transit time, and the compensated pulse transit time.

20. The biosignal measurement method as claimed in claim 19, wherein the diastolic pressure value is calculated according to an equation

21. The biosignal measurement method as claimed in claim 15, wherein the current pulse transit time is compensated according to an equation