Therapy delivery mode selection

• US 20060247739A1
• Filed: 04/29/2005
• Published: 11/02/2006
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Skime, Robert M., Wahlstrand, Carl D.
• Granted Patent: US 7,389,147 B2
• Time in Patent Office: Days
• US Class Current: 607/62
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/103 Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/37247 User interfaces, e.g. input or presentation means
• CPC Class Codes: G16H 40/63 for local operation

Abstract

Techniques for selectably providing either constant voltage or constant current stimulation are described. A programming device provides a user interface by which a user selects either constant voltage or constant current stimulation, and selects either a voltage or current amplitude based on the selected stimulation mode. The programming device configures a medical device to provide the selected mode of stimulation at the selected amplitude. For example, when a medical device has constant voltage stimulation circuitry, e.g., circuitry including a voltage source, and the user selects constant current stimulation, the programming device configures the medical device to adjust the voltage amplitude based on a measured impedance to provide substantially constant current amplitude.

Claims

1. A programming device comprising:

a user interface; and

a processor that prompts a user for selection of one of a constant current mode or a constant voltage mode via the user interface, receives a selection of one of the modes from the user via the user interface, and configures a medical device according to the selected mode.

2. The programming device of claim 1, wherein the processor prompts the user for one of a voltage or current amplitude based on the selected mode.

3. The programming device of claim 1, wherein the processor configures the medical device to measure an impedance presented to stimulation circuitry of the medical device based on the selected mode.

4. The programming device of claim 3, wherein, when the medical device comprises constant voltage stimulation circuitry and the user selects the constant current mode, the processor configures the medical device to measure the presented impedance and adjust a stimulation voltage amplitude based on the measured impedance to deliver stimulation with a substantially constant current amplitude.

5. The programming device of claim 3, wherein, when the medical device comprises constant current stimulation circuitry and the user selects the constant voltage mode, the processor configures the medical device to measure the presented impedance and adjust a stimulation current amplitude based on the measured impedance to deliver stimulation with a substantially constant voltage amplitude.

6. The programming device of claim 3, wherein the processor provides an impedance measurement frequency to the medical device.

7. The programming device of claim 6, wherein the measurement frequency is variable as a function of patient activity, and the processor provides a relationship between measurement frequency and patient activity to the medical device.

8. A method comprising:

prompting a user for selection of one of a constant current mode or a constant voltage mode;

receiving a selection of one of the modes from the user; and

configuring a medical device according to the selected mode.

9. The method of claim 8, further comprising prompting the user for one of a voltage or current amplitude based on the selected mode.

10. The method of claim 8, wherein configuring the medical device comprises configuring the medical device to measure an impedance presented to stimulation circuitry of the medical device based on the selected mode.

11. The method of claim 10, wherein, when the medical device comprises constant voltage stimulation circuitry and the user selects the constant current mode, configuring the medical device comprises configuring the medical device to measure the presented impedance and adjust a stimulation voltage amplitude based on the measured impedance to deliver stimulation with a substantially constant current amplitude.

12. The method of claim 10, wherein, when the medical device comprises constant current stimulation circuitry and the user selects the constant voltage mode, configuring the medical device comprises configuring the medical device to measure the presented impedance and adjust a stimulation current amplitude based on the measured impedance to deliver stimulation with a substantially constant voltage amplitude.

13. The method of claim 8, further comprising providing a measurement frequency to the medical device for measurement of the impedance.

14. The method of claim 13, wherein the frequency is variable as a function of patient activity, and providing a frequency comprises providing a relationship between frequency and patient activity.

15. A computer-readable medium comprising instructions that cause a programmable processor to:

prompt a user for selection of one of a constant current mode or a constant voltage mode;

receive a selection of one of the modes from the user; and

configure a medical device according to the selected mode.

16. The computer-readable medium of claim 15, wherein the instructions that cause a programmable processor to configure the medical device comprise instructions that cause a programmable processor to configure the medical device to measure an impedance presented to stimulation circuitry of the medical device based on the selected mode.

17. The computer-readable medium of claim 16, wherein, when the medical device comprises constant voltage stimulation circuitry and the user selects the constant current mode, the instructions that cause a programmable processor to configure the medical device comprise instructions that cause a programmable processor to configure the medical device to measure the presented impedance and adjust a stimulation voltage amplitude based on the measured impedance to deliver stimulation with a substantially constant current amplitude.

18. The computer-readable medium of claim 16, wherein, when the medical device comprises constant current stimulation circuitry and the user selects the constant voltage mode, the instructions that cause a programmable processor to configure the medical device comprise instructions that cause a programmable processor to configure the medical device to measure the presented impedance and adjust a stimulation current amplitude based on the measured impedance to deliver stimulation with a substantially constant voltage amplitude.

19. A medical device comprising:

stimulation circuitry configured to deliver one of constant voltage or constant current stimulation;

an activity sensor to sense patient activity;

an impedance measurement circuit for measuring an impedance presented to the stimulation circuitry; and

a processor to determine a measurement frequency for impedance measurements based on the sensed patient activity, control the impedance measurement circuit to measure the presented impedance at the measurement frequency, and adjust an amplitude of the stimulation based on the measured impedance to substantially provide the other of constant voltage or constant current stimulation.

20. The medical device of claim 19, wherein the activity sensor comprises at least one of an accelerometer or a piezoelectric element.

21. The medical device of claim 19, wherein patient activity includes at least one of motion, footfalls, or posture.

22. The medical device of claim 19, wherein the processor controls the stimulation circuitry to deliver a signal, controls the impedance measurement circuit to measure at least one of a voltage or current during delivery of the signal, and determines the presented impedance based on the measured voltage or current.

23. The medical device of claim 19, wherein the processor controls the stimulation circuitry to deliver stimulation to a patient, and controls the impedance measurement circuit to measure the impedance during delivery of the stimulation.

24. The medical device of claim 19, wherein the processor compares the sensed patient activity to a threshold value, and determines the measurement frequency based on the comparison.

25. The medical device of claim 24, wherein the processor selects a greater mesaurement frequency when the patient activity exceeds the threshold.

26. The medical device of claim 19, further comprising a memory that stores information defining a relationship between patient activity and measurement frequency, wherein the processor determines the measurement frequency based on the senses patient activity and the information.

27. The medical device of claim 19, wherein the medical device comprises an implantable medical device.

28. The medical device of claim 19, wherein the medical device comprises a neurostimulator.

29. A method comprising:

sensing patient activity;

determining a measurement frequency for impedance measurements based on the sensed activity;

measuring an impedance presented to stimulation circuitry of a medical device at the determined measurement frequency, wherein the stimulation circuitry is configured to provide one of constant voltage or constant current stimulation; and

adjusting an amplitude of the stimulation based on the measured impedance to substantially provide the other of constant voltage or constant current stimulation.

30. The method of claim 29, wherein sensing patient activity comprises sensing at least one of motion, footfalls, or posture.

31. The method of claim 29, wherein determining an impedance measurement frequency comprises:

comparing the sensed patient activity to a threshold value; and

determining the measurement frequency based on the comparison.

32. The method of claim 31, wherein determining the measurement frequency based on the comparison comprises selecting a greater measurment frequency when the activity level exceeds the threshold.

33. The method of claim 29, further comprising storing information defining a relationship between patient activity and measurement frequency, wherein determining the measurmeent frequency comprises determining the measurement frequency based on the sensed patient activity and the information.

34. A medical device comprising:

means for sensing patient activity;

means for determining a measurement frequency for impedance measurements based on the sensed activity;

means for measuring an impedance presented to stimulation circuitry of a medical device at the determined measurement frequency, wherein the stimulation circuitry is configured to provide one of constant voltage or constant current stimulation; and

means for adjusting an amplitude of the stimulation based on the measured impedance to substantially provide the other of constant voltage or constant current stimulation.