System and method for determining changes in a body state

Patent metadata

Field	Value
Publication number	US-9420958-B2
Application number	US-201313843077-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Mar 15, 2013
Publication date	Aug 23, 2016
Grant date	Aug 23, 2016

Abstract

A method and a system for determining changes in a body state of an individual including receiving a signal from a monitoring system, where the signal indicates a measurement of cardiac activity of the individual over a period of time and determining at least one signal feature, where the signal feature is a reoccurring event of the signal over the period of time. The method also includes determining a first interval between two successive signal features and determining a second interval between two successive first intervals. A derivative is calculated based on the second interval. Changes in the body state are identified based on the derivative.

First claim

The invention claimed is:

1. A computer-implemented method for determining changes in a body state of an individual, comprising:
receiving a signal from a monitoring system, said signal indicating a measurement of cardiac activity over a period of time;
determining at least one signal feature and a value representative of the signal feature, wherein the signal feature is a reoccurring event of the signal over the period of time;
calculating a first interval as a difference between a value representative of a first signal feature and a value representative of a second signal feature, wherein the first signal feature and the second signal feature are successive in the signal between two successive signal features;
calculating a second interval as a difference between a value representative of a third signal feature and a value representative of a fourth signal feature, wherein the third signal feature and the fourth signal feature are successive in the signal;
calculating a difference between the first interval and the second interval between two successive first intervals;
calculating a derivative based on the difference between the first interval and the second interval; and
identifying changes in the body state based on the derivative.

2. The computer-implemented method of claim 1 , wherein the signal is measured by a contactless sensor.

3. The computer-implemented method of claim 2 , wherein the signal is one of an electric signal, an acoustic or an optical signal representing the measurement of cardiac activity.

4. The computer-implemented method of claim 1 , wherein the signal feature is a peak of the signal.

5. The computer-implemented method of claim 1 , wherein the signal is an electrocardiogram signal and the signal feature is an R wave of the electrocardiogram signal.

6. The computer-implemented method of claim 1 , wherein identifying changes in the body state based on the derivative further includes extracting a series of contiguous heart rate accelerations or decelerations based on the derivative.

7. The computer-implemented method of claim 6 , wherein the series of contiguous heart rate accelerations or decelerations correlate to a change in the body state.

8. The computer-implemented method of claim 6 , wherein identifying changes in the body state based on the derivative further includes calculating a threshold based on a count of the contiguous heart rate accelerations or decelerations in the series.

9. The computer-implemented method of claim 7 , wherein identifying changes in the body state based on the derivative further includes generating a graphic representation and identifying changes in the body state as a function of the graphic representation.

10. A computer-implemented method for analyzing transitions in a body state, comprising:
receiving a signal from an individual indicating a measurement of cardiac activity over a period of time;
calculating a plurality of first interval values, wherein each interval value of the plurality of first interval values is calculated as a difference between two successive signal features of the signal;
calculating a plurality of second interval values, wherein each interval of the plurality of second intervals is calculated as a difference between two successive first intervals of the plurality of first intervals;
calculating a plurality of derivatives based on each of the plurality of second interval values;
extracting a plurality of heart rate accelerations or decelerations from the plurality of derivatives; and
identifying a transition in the body state based on the plurality of heart rate accelerations or decelerations.

11. The computer-implemented method of claim 10 , further including transmitting the signal from a monitoring system associated with the individual, wherein said signal is one of an electrical signal, an acoustic signal or an optical representing the measurement of cardiac activity.

12. The computer-implemented method of claim 11 , wherein receiving a signal further includes processing the signal into a plurality of waveforms, each one of said waveforms indicating a heart beat.

13. The computer-implemented method of claim 10 , wherein a sign of each derivative in the plurality of derivatives indicates a heart rate acceleration or deceleration.

14. The computer-implemented method of claim 10 , wherein identifying a transition in the body state further includes generating a graphical representation illustrating a first set of contiguous derivatives from the plurality of derivatives wherein each derivative of the first set of contiguous derivatives have the same sign and a second set of contiguous derivatives from the plurality of derivatives where each derivative of the second set of contiguous derivatives have the same sign, and identifying the transitions in the body state as a function of a distance between the first set and the second set.

15. The computer-implemented method of claim 1 , wherein a set of contiguous derivatives having a negative sign correlates to a burst of sympathetic activity and a set of contiguous derivatives having a positive sign correlates to a burst of parasympathetic activity.

16. A computer system for determining changes in a body state of an individual, comprising:
a monitoring system configured to monitor cardiac activity;
a signal receiving module configured to receive a signal from the monitoring system, said signal representing a measurement of cardiac activity over a period of time;
a feature determination module configured to determine a signal feature and a value representative of the signal feature, wherein the signal feature is a reoccurring event of said signal over the period of time;
an interval determination module configured to calculate a first interval as a difference between a value representative of a first signal feature and a value representative of a second signal feature, wherein the first signal feature and the second signal feature are successive in the signal,
configured to calculate a second interval as a difference between a value representative of a third signal feature and a value representative of a fourth signal feature, wherein the third signal feature and the fourth signal feature are successive in the signal,
and configured to calculate a difference between the first interval and the second interval;
a derivative calculation module configured to calculate a derivative of a heart rate based on the difference between the first interval and the second interval; and
an identification module configured to identify changes in the body state based on the derivative.

17. The computer system of claim 16 , wherein the monitoring system further includes a plurality of contactless sensors for monitoring cardiac activity of the individual.

18. The computer system of claim 16 , wherein the signal is one of an electrical signal, an acoustic signal or an optical signal representing the measurement of cardiac activity.

19. The computer system of claim 16 , the identification module further configured to extract a series of contiguous heart rate accelerations or decelerations based on the derivative.

20. The computer system of claim 19 , wherein the series of contiguous heart rate accelerations or decelerations correlate to a change in the body state.

21. A non-transitory computer-readable medium storing computer-executable instructions that when executed by a computer, which includes at least a processor, cause the computer to perform a method, the method com

Assignees

• Honda Motor Co Ltd

Inventors

• Fung Kin C
• Dick Timothy J
• Hall Jr Charles William

Classifications

• A61B5/02416 Primary

  using photoplethysmograph signals, e.g. generated by infrared radiation (A61B5/14552 takes precedence) · CPC title

• A61B5/024 Primary

  Measuring pulse rate or heart rate · CPC title

• A61B5/0456

  Human Necessities · mapped topic

• A61B5/0245

  by using sensing means generating electric signals, {i.e. ECG signals} · CPC title

• A61B5/7239

  using differentiation including higher order derivatives · CPC title