Using activity-based rest disturbance as a metric of sleep apnea

• US 20040002742A1
• Filed: 06/27/2002
• Published: 01/01/2004
• Est. Priority Date: 06/27/2002
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Florio, Joseph J.
• Granted Patent: US 7,117,036 B2
• Time in Patent Office: Days
• US Class Current: 607/19
• CPC Class Codes: A61N 1/3601 of respiratory organs
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration

Abstract

An implantable cardiac device is programmed to monitor short term activity changes that occur while a patient is at rest to produce a sleep disturbance metric that is useful in analyzing and/or treating sleep apnea. After the implantable cardiac device confirms that a patient is at rest, the device monitors an instantaneous signal from an activity sensor to detect variances from normal rest mode activity. When the variances exceed a preset threshold for a short time period (e.g., less than 30-40 sec.), the patient is presumed to be experiencing a form of sleep disturbance as opposed to conscious or wakeful activity. These short term events are recorded as sleep disturbance events. The sleep disturbance metric are reported to a physician as a diagnostic to help ascertain the severity of sleep apnea or to evaluate the effectiveness of pacing therapies being applied to treat sleep apnea.

Claims

1. An implantable cardiac device comprising:

sensing circuitry to sense a patient'"'"'s activity; and

a sleep disturbance detector to detect when a patient, who is at rest, is experiencing sleep disturbance based on the patient'"'"'s activity.

2. An implantable cardiac device as recited in claim 1, wherein the sensing circuitry comprises at least one of an activity sensor, a position sensor, an accelerometer, and a posture sensor.

3. An implantable cardiac device as recited in claim 1, wherein the sensing circuitry comprises:

a first sensor to detect when the patient is in a reclined position; and

a second sensor to sense the patient'"'"'s activity while the patient is in the reclined position.

4. An implantable cardiac device as recited in claim 1, wherein the sleep disturbance detector is configured to detect the sleep disturbance by determining when the patient'"'"'s activity exceeds a threshold for a brief period that is less than a preset time limit.

5. An implantable cardiac device as recited in claim 1, wherein the sleep disturbance detector is configured to detect the sleep disturbance by determining when the patient'"'"'s activity rises above a threshold for less than approximately 40 seconds.

6. An implantable cardiac device as recited in claim 1, wherein the sleep disturbance detector comprises a counter to count a number of sleep disturbances that the patient experiences in a predefined timeframe.

7. An implantable cardiac device as recited in claim 1, further comprising a memory to store events of sleep disturbance.

8. An implantable cardiac device as recited in claim 1, further comprising:

a therapy module to prescribe a pacing therapy for treating sleep apnea from among multiple different pacing therapies;

a pulse generator to generate pacing pulses according to the prescribed pacing therapy for an evaluation timeframe; and

the sleep disturbance detector counting a number of sleep disturbances experienced during the evaluation timeframe of the prescribed pacing therapy.

9. An implantable cardiac device comprising:

an activity sensor to sense a patient'"'"'s activity;

a processor to confirm that the patient is at rest based on the patient'"'"'s activity and while the patient is resting, to detect one or more sleep disturbances that occur when the patient'"'"'s activity rises above a threshold for less than a preset time limit; and

a memory to store disturbance data pertaining to the sleep disturbances detected by the processor.

10. An implantable cardiac device as recited in claim 9, further comprising a second sensor to detect when the patient is in a reclined position, the second sensor being selected from a group comprising a position sensor, a posture sensor, and an accelerometer.

11. An implantable cardiac device as recited in claim 9, wherein the processor is configured to count a number of sleep disturbances that occur during a predetermined time period.

12. An implantable cardiac device as recited in claim 11, wherein the processor derives a frequency of sleep disturbances based on the number of sleep disturbances that occur during the predetermined time period.

13. An implantable cardiac device as recited in claim 9, wherein the processor comprises a timer to time duration of the patient'"'"'s activity to determine whether the duration is less than the preset time limit.

14. An implantable cardiac device as recited in claim 9, further comprising:

a therapy module to prescribe a pacing therapy for treating sleep apnea from among multiple different pacing therapies;

a pulse generator to generate pacing pulses according to the prescribed pacing therapy for an evaluation timeframe; and

the sleep apnea detector measuring durations of episodes experienced during the evaluation timeframe of the prescribed pacing therapy.

15. An implantable cardiac device comprising:

activity detection means for detecting when a patient'"'"'s activity rises above a preset threshold;

timing means for timing a duration that the patient'"'"'s activity is above the preset threshold; and

identification means for identifying the patient'"'"'s activity as sleep disturbance in an event that the patient'"'"'s activity is above the preset threshold for less than a time limit.

16. An implantable cardiac device as recited in claim 15, wherein the activity detection means comprises:

a sensor to output an activity signal; and

a processor to determine when the activity signal exceeds the preset threshold.

17. An implantable cardiac device as recited in claim 16, wherein the sensor is selected from one or more sensors selected from a group of sensors comprising an activity sensor, an accelerometer, a position sensor, and a posture sensor.

18. An implantable cardiac device as recited in claim 15, wherein the activity detection means comprises:

a posture sensor to detect when the patient is in a reclined position;

an activity sensor to detect the patient'"'"'s activity while the patient is in the reclined position; and

a processor to determine when the activity signal, taken while the patient is in the reclined position, exceeds the preset threshold.

19. An implantable cardiac device as recited in claim 15, further comprising counting means for counting a number of sleep disturbances that occur during a predefined timeframe.

20. An implantable cardiac device as recited in claim 15, further comprising storage means for storing data pertaining to events identified as sleep disturbance.

21. An implantable cardiac device as recited in claim 20, further comprising transmission means for transmitting the data to an external device.

22. An implantable cardiac device as recited in claim 15, further comprising apnea therapy means for administering a pacing therapy to counteract the sleep apnea.

23. An implantable and programmable cardiac device having a memory and a processor, the cardiac device being programmed to perform tasks comprising:

detecting a heightened level of patient activity while the patient is at rest;

timing a duration of the heightened level of patient activity; and

in an event that the duration is less than a predefined time limit, identifying the heightened level of patient activity as sleep disturbance.

24. An implantable and programmable cardiac device as recited in claim 23, further programmed to perform tasks comprising detecting the heightened level of patient activity by comparing an instantaneous activity signal to a threshold.

25. An implantable and programmable cardiac device as recited in claim 23, further programmed to perform tasks comprising counting a number of sleep disturbances that occur within a predetermined timeframe.

26. An implantable and programmable cardiac device as recited in claim 23, further programmed to perform tasks comprising administering different pacing therapies for treating sleep apnea and collecting sleep disturbance metrics during individual therapies to evaluate effectiveness of the different pacing therapies.

27. A system comprising:

an implantable cardiac device configured to administer different pacing therapies for treating sleep apnea, the implantable cardiac device being further configured to collect sleep disturbance metrics pertaining to sleep disturbances detected during the different pacing therapies and to export the sleep disturbance metrics to an external device; and

a computing system to analyze the sleep disturbance metrics collected by the implantable cardiac device and exported to the external device.

28. A system as recited in claim 27, wherein the implantable cardiac device monitors patient activity and identifies sleep disturbances when the patient activity increases above a threshold for less than a preset time period.

29. A system as recited in claim 27, wherein the implantable cardiac device administers each pacing therapy for a predefined evaluation timeframe and the computer system analyzes the sleep disturbance metrics collected for the different pacing therapies to identify one or more therapies that are effective at reducing sleep disturbances as a metric for treating sleep apnea.

30. A system as recited in claim 27, wherein the implantable cardiac device comprises:

an activity sensor to sense a patient'"'"'s activity; and

a processor to confirm that the patient is at rest based on the patient'"'"'s activity and while the patient is resting, to detect sleep disturbances that occur when the patient'"'"'s activity rises above a threshold for less than a preset time limit.

31. A method implemented by an implantable cardiac device, comprising:

detecting a heightened level of patient activity while the patient is at rest;

timing a duration of the heightened level of patient activity; and

in an event that the duration is less than a predefined time limit, identifying the heightened level of patient activity as sleep disturbance.

32. A method as recited in claim 31, wherein the detecting comprises determining when a patient is in a reclined position and monitoring the patient'"'"'s activity while the patient is in the reclined position.

33. A method as recited in claim 31, wherein the detecting comprises monitoring an instantaneous signal from an activity sensor.

34. A method as recited in claim 31, wherein the time limit is approximately forty seconds.

35. A method as recited in claim 31, further comprising counting the sleep disturbances.

36. A method as recited in claim 31, further comprising storing at least one of a count or a frequency of the sleep disturbances.

37. A method as recited in claim 31, further comprising:

administering multiple different pacing therapies to treat the sleep apnea; and

evaluating the pacing therapies based on how the pacing therapies affect the sleep disturbances.

38. A computer readable medium having computer-executable instructions that, when executed, direct an implantable cardiac device to perform the method as recited in claim 31.

39. A method comprising:

determining that a patient is at rest; and

while the patient is at rest,

monitoring an instantaneous activity signal indicative of a patient'"'"'s activity;

detecting when the instantaneous activity signal exceeds a threshold;

timing a duration that the instantaneous activity signal exceeds the threshold; and

in an event that the instantaneous activity signal exceeds the threshold for less than a preset time, recording the patient'"'"'s activity as a sleep disturbance.

40. A method as recited in claim 39, further comprising determining a frequency of sleep disturbances that occur within a predetermined timeframe.

41. A method as recited in claim 39, further comprising counting the sleep disturbances.

42. A method as recited in claim 39, further comprising identifying the patient'"'"'s activity as meaningful activity if the instantaneous activity signal exceeds the threshold for more than the preset time.

43. A method as recited in claim 39, further comprising:

administering multiple different pacing therapies to treat the sleep apnea;

collecting sleep disturbance metrics for individual pacing therapies; and

evaluating the pacing therapies based on how the pacing therapies affect the sleep disturbance metrics.

44. A computer readable medium having computer-executable instructions that, when executed, direct an implantable cardiac device to perform the method as recited in claim 39.

45. A method comprising:

administering multiple different pacing therapies to treat sleep apnea using an implantable cardiac device, such that each pacing therapy is administered for an evaluation timeframe;

compiling sleep disturbance metrics pertaining to sleep disturbances detected during each evaluation timeframe; and

analyzing the sleep disturbance metrics to evaluate how effective the different pacing therapies are at treating the sleep apnea.

46. A method as recited in claim 45, wherein the compiling comprises counting the sleep disturbances that occur during the evaluation timeframe.

47. A method as recited in claim 45, wherein the compiling comprises determining a frequency of the sleep disturbances for each of the pacing therapies.

48. A method as recited in claim 45, further comprising transmitting the sleep disturbance metrics to an external device and performing the analyzing at the external device.