APPARATUS FOR EVALUATING BIOLOGICAL CONDITION, METHOD FOR THE SAME, AND COMPUTER PROGRAM PRODUCT

• US 20100185101A1
• Filed: 01/18/2010
• Published: 07/22/2010
• Est. Priority Date: 01/19/2009
• Status: Active Grant

• Current Assignee: DENSO Corporation, Nippon Medical School Foundation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: DENSO Corporation, Nippon Medical School Foundation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: SAKAI, Kazuhiro, NANBA, Shinji, OSAKA, Motohisa, FUWAMOTO, Yoshitaka, KATOH, Takao
• Granted Patent: US 8,684,938 B2
• Time in Patent Office: Days
• US Class Current: 600/483
• CPC Class Codes: A61B 5/02455 provided with high/low alarm devices
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

A biological condition evaluation apparatus determines a symptom of a heart abnormality based on at least one index calculated from a heartbeat interval and/or a pulse interval. The apparatus determines whether it is in a referential period where an amount of change in the index is comparatively small. The apparatus determines whether a plurality of conditions are satisfied or not in an evaluation period set after the referential period. One condition is that an amount of change in the index in the evaluation period is greater than that observed during the referential period. Another condition is that a rate of change in the index is equal to or greater than a predetermined threshold value. The apparatus determines that there is a symptom of a heart abnormality, when both the conditions are satisfied.

Claims

1. An apparatus for evaluating biological condition, which determines a symptom of a heart abnormality based on biological information that is at least one of a heartbeat interval and a pulse interval, the apparatus comprising:

means for calculating an index by performing the frequency analysis on at least one of the heartbeat interval and the pulse interval, the index being indicative of the sympathetic nerve activity;

means for determining whether it is in a referential period which is a time period in which the index satisfies a predetermined condition which shows that a grade of change in the index calculated in the index calculating means is smaller than a predetermined value over a predetermined period; and

means for determining a symptom of a heart abnormality after the predetermined condition for the referential period is satisfied, the symptom being determined when the following both conditions (1) and (2) are satisfied during an evaluation period which is set after the referential period,

(1) an amount of change in the index in an increasing and decreasing is equal to or greater than a predetermined threshold value which indicates that the amount of change is greater than an amount of change in the index observed during the referential period, and

(2) a rate of change in the index in an increasing and decreasing is equal to or greater than a predetermined threshold value.

2. The apparatus for evaluating biological condition according to claim 1, wherein

the index is expressed by the natural logarithm.

3. The apparatus for evaluating biological condition according to claim 1, wherein

the predetermined condition for determining the referential period is that a change in the index is equal to or smaller than a predetermined threshold value.

4. The apparatus for evaluating biological condition according to claim 1, wherein

the predetermined threshold value for the amount of change in the index is a value of mean(index)±

1 SD, where the mean(index) is an average value of the index in the referential period and 1 SD is a unit of the standard deviation of the index in the referential period.

5. The apparatus for evaluating biological condition according to claim 1, wherein

the predetermined threshold value for the amount of change in the index is a variable according to the absolute value of the index in the referential period.

6. The apparatus for evaluating biological condition according to claim 1, wherein

the referential period is defined by using past data of the index.

7. The apparatus for evaluating biological condition according to claim 1, wherein

the abnormality determining means determines that the condition (1) for an amount of change in the index is satisfied when an amount of change in the index in the evaluation period is within a range from mean(index)±

1.5 SD to mean(index)±

3.0 SD, where the mean(index) is an average value of the index in the referential period and SD is the standard deviation of the index in the referential period.

8. The apparatus for evaluating biological condition according to claim 1, wherein

the abnormality determining means performs the determination based on a gradient of a regression line of the index during the evaluation period.

9. The apparatus for evaluating biological condition according to claim 8, wherein

the determination, using the gradient of the regression line is performed based on a threshold value that is variable according to the absolute value of the index during the referential period.

10. The apparatus for evaluating biological condition according to claim 8, wherein

the abnormality determining means changes an abnormal grade showing grade of the abnormality according to grade of the gradient of the regression line.

11. The apparatus for evaluating biological condition according to claim 1, wherein

the index calculating means calculates a first index that is the index indicative of the sympathetic nerve activity and a second index indicative of the parasympathetic nerve activity,

the referential period determining means and the abnormality determining means determine the symptom of the heart abnormality based on both of the indexes respectively, and

the abnormality determining means determines a final result of determination when the abnormality determining means determines that both the first and second indexes indicate the symptom of the heart abnormality respectively.

12. The apparatus for evaluating biological condition according to claim 1, wherein

the index calculating means calculates a first index that is the index indicative of the sympathetic nerve activity and a second index indicative of the parasympathetic nerve activity,

the referential period determining means and the abnormality determining means determine the symptom of the heart abnormality based on both of the indexes respectively, and

the abnormality determining means determines an abnormal pattern which is used for the determination by adding a condition in which the first index and the second index change in opposite increasing and decreasing directions.

13. The apparatus for evaluating biological condition according to claim 1, wherein

the abnormality determining means, avoids determining the symptom when the abnormality determining means determines that the driver is in a time of beginning sleep, a time of amid sleep, or a time of getting up.

14. The apparatus for evaluating biological condition according to claim 1, wherein

the apparatus is able to be mounted on a vehicle.

15. The apparatus for evaluating biological condition according to claim 1, wherein

the determination is carried out when the vehicle is driven.

16. The apparatus for evaluating biological condition according to claim 1, further comprising:

at least one of

a sensor which detects biological condition,

an output device which, outputs an announcement corresponding to the result of the determination, and

a control device which performs control according to the result of the determination, wherein

the sensor performs, in response to the determination of the symptom, at least one measurement among an electrocardiograph measurement, a blood-pressure measurement, and other biological measurement different from one that is used in the determination, and wherein

the output device performs, in response to the determination of the symptom, at least one output among an announcement output suggesting other abnormality determination different from one that is used in the determination, an announcement output asking subjective symptoms, an announcement output suggesting an electrocardiograph measurement, an announcement output suggesting a blood-pressure measurement and an announcement output suggesting other biological measurement different from one that is used in the determination.

17. A method for evaluating biological condition, which determines a symptom of a heart abnormality based on biological information that is at least one of a heartbeat interval and a pulse interval, the method comprising the steps of:

calculating at least one of a first index and a second index by performing the frequency analysis on at least one of the heartbeat interval and the pulse interval, the first index being indicative of the sympathetic nerve activity, and the second index being indicative of the parasympathetic nerve activity;

determining whether it is in a referential period which is a time period in which the index satisfies a predetermined condition which shows that a grade of change in the index calculated in the index calculating means is smaller than a predetermined value over a predetermined period; and

determining a symptom of a heart abnormality after the predetermined condition for the referential period is satisfied, the symptom being determined when the following both conditions (1) and (2) are satisfied during an abnormality evaluation period which is set after the referential period,

(1) an amount of change in the index in an increasing and decreasing is equal to or greater than a predetermined threshold value which indicates that the amount of change is greater than an amount of change in the index observed during the referential period, and

(2) a rate of change in the index in an increasing and decreasing is equal to or greater than a predetermined threshold value.

18. The method for evaluating biological condition, according to claim 17, wherein

the index calculating step calculates both the first and second indexes,

the referential period determining step determines whether the both indexes indicates that it is the referential period, and

the abnormality determining step determines the symptom of the heart abnormality with respect to both the indexes.

19. The method for evaluating biological condition according to claim 18, wherein

the abnormality determining step discriminately determines whether both the indexes are in

a first pattern in which changes in both the indexes indicate a symptom of a heart abnormality,

a second pattern in which one of changes in both the indexes indicates a symptom of a heart abnormality,

a third pattern in which changes in both the indexes indicate a symptom of a heart abnormality, and corresponds to opposite changes to the first pattern.

20. A computer program product stored in a computer readable storage medium, the computer program product comprising a computer program that, when executed on a computer, causes the computer to perform the method claimed in claim 17.