KINETICS OF PHYSIOLOGICAL RESPONSE TO ACTIVITY DURING ACTIVITIES OF DAILY LIVING

• US 20110201943A1
• Filed: 02/10/2011
• Published: 08/18/2011
• Est. Priority Date: 02/16/2010
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Liu, Kassity Yefei, Baker, Lemont, Beck, Kenneth C.
• Granted Patent: US 9,730,618 B2
• Time in Patent Office: Days
• US Class Current: 600/483
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/50 for simulation or modelling of medical disorders

Abstract

A physiological response to activity (PRA) during a subject'"'"'s activities of daily living (ADL) can be used, such as to generate useful diagnostic information about the subject. This can involve using a template, such as an impulse response template. The technique can be used with an implantable or other ambulatory medical monitoring or therapy device, such as a cardiac function management device, or with a local or remote external interface device.

Claims

1. An apparatus comprising:

an activity sensor circuit, configured to receive an activity signal indicative of physical activity of a subject during the subject'"'"'s activities of daily living;

a physiological sensor circuit, configured to receive a concurrent actual physiological response signal, different from the activity signal, during the subject'"'"'s activities of daily living;

a signal processor circuit, configured to generate an approximate physiological response signal, including;

convolving the activity signal with a template for generating the approximate physiological response signal, the template including at least one characteristic parameter; and

comparing information from the approximate physiological response signal with information from the actual physiological response signal to determine the at least one characteristic parameter; and

wherein the signal processor circuit is configured to provide information from the at least one characteristic parameter to a user or process.

2. The apparatus of claim 1, wherein the activity sensor circuit includes an accelerometer configured to receive the activity signal including an acceleration signal, and wherein receiving the concurrent actual physiological response signal includes receiving at least one of a heart rate or interval signal or a respiration signal.

3. The apparatus of claim 1, wherein the signal processor circuit is configured to generate the approximate physiological response signal including iteratively generating the approximate physiological response signal so as to reduce or minimize a difference between the approximate physiological response signal and the actual physiological response signal.

4. The apparatus of claim 1, wherein the signal processor circuit includes a time-to-frequency domain transform circuit, and wherein the signal processor circuit is configured to convolve the activity signal with a template including multiplying a frequency domain representation of the activity signal with a frequency domain representation of the impulse response template.

5. The apparatus of claim 1, wherein the signal processor circuit is configured to convolve the activity signal with a template, including convolving the activity signal with an impulse response template.

6. The apparatus of claim 5, wherein the signal processor circuit is configured to convolve the activity signal with a template including using a time-domain impulse response template that includes an exponential function of time, and wherein the at least one characteristic parameter includes at least one of a scaling constant of the exponential function or a time constant of the exponential function.

7. The apparatus of claim 6, wherein the signal processor circuit is configured to trend the at least one characteristic parameter over time, and is configured to provide a diagnostic of the subject using the trended characteristic parameter.

8. The apparatus of claim 7, wherein the at least one characteristic parameter includes the time constant, and wherein the signal processor circuit is configured to provide the diagnostic indicating worsening of cardiac status when the trended time constant increases over time.

9. The apparatus of claim 7, wherein the at least one characteristic parameter includes the scaling constant, and wherein the signal processor circuit is configured to provide the diagnostic indicating worsening of chronotropic incompetence when the trended scaling constant decreases over time.

10. The apparatus of claim 7, wherein the at least one characteristic parameter includes the scaling constant, and wherein the signal processor circuit is configured to provide the diagnostic indicating a worsening of cardiac status when the trended scaling constant increases over time.

11. A device-readable medium including instructions that, when performed by the device, comprise:

receiving an activity signal indicative of physical activity of a subject during the subject'"'"'s activities of daily living;

receiving a concurrent actual physiological response signal, different from the activity signal, during the subject'"'"'s activities of daily living;

generating an approximate physiological response signal, including;

convolving the activity signal with a template for generating the approximate physiological response signal, the template including at least one characteristic parameter; and

comparing information from the approximate physiological response signal with information from the actual physiological response signal to determine the at least one characteristic parameter; and

providing information from the at least one characteristic parameter to a user or process.

12. The device-readable medium of claim 11, wherein receiving the activity signal includes receiving an acceleration signal, and wherein receiving the concurrent actual physiological response signal includes receiving at least one of a heart rate or interval signal or a respiration signal.

13. The device-readable medium of claim 11, wherein generating the approximate physiological response signal includes iteratively generating the approximate physiological response signal so as to reduce or minimize a difference between the approximate physiological response signal and the actual physiological response signal.

14. The device-readable medium of claim 11, wherein convolving the activity signal with a template includes multiplying a frequency domain representation of the activity signal with a frequency domain representation of the impulse response template.

15. The device-readable medium of claim 11, wherein convolving the activity signal with a template includes convolving the activity signal with an impulse response template.

16. The device-readable medium of claim 15, wherein convolving the activity signal with a template includes using a time-domain impulse response template that includes an exponential function of time, and wherein the at least one characteristic parameter includes at least one of a scaling constant of the exponential function or a time constant of the exponential function.

17. The device-readable medium of claim 16, comprising trending the at least one characteristic parameter over time, and providing a diagnostic of the subject using the trended characteristic parameter.

18. The device-readable medium of claim 17, wherein the at least one characteristic parameter includes the time constant, and wherein the diagnostic is configured to indicate worsening of cardiac status when the trended time constant increases over time.

19. The device-readable medium of claim 17, wherein the at least one characteristic parameter includes the scaling constant, and wherein the diagnostic is configured to indicate worsening of chronotropic incompetence when the trended scaling constant decreases over time.

20. The device-readable medium of claim 17, wherein the at least one characteristic parameter includes the scaling constant, and wherein the diagnostic is configured to indicate a worsening of cardiac status when the trended scaling constant increases over time.