Neurostimulation method and system for active emulation of passive discharge in presence of MRI/EMI interference

Patent metadata

Field	Value
Publication number	US-11857789-B2
Application number	US-202117186630-A
Country	US
Kind code	B2
Filing date	Feb 26, 2021
Priority date	May 2, 2019
Publication date	Jan 2, 2024
Grant date	Jan 2, 2024

Abstract

A neurostimulation (NS) system and method are provided. The NS system includes an array of electrodes positioned within a patient. The array of electrodes includes an active electrode. The active electrode is configured to be a cathode electrode located proximate to neural tissue of interest that is associated with a target region. The NS system includes an anode electrode and an electromagnetic interference (EMI) antenna. A control circuit is configured to control delivery of a NS therapy during a therapy delivery interval. The NS therapy is to be delivered between the anode electrode and the active electrode. The NS system develops a residual voltage between the anode electrode and the active electrode over the therapy delivery interval. A current regulator (CR) circuit is connected to the cathode electrode. The CR circuit is configured to control current flow through the cathode electrodes. During a discharge operation, the control circuit is configured to manage the CR circuit to control a discharge current flow over the discharge operation to discharge the residual voltage after therapy delivery in a manner that follows an actively emulated passive discharge (AEPD) profile. During the discharge operation, the CR circuit is connected to the inactive electrode. The CR circuit receives, as a first input, an EMI feedback signal from the EMI antenna. The CR circuit is configured to regulate the discharge current flow through the active electrode based on the EMI feedback signal, to maintain the AEPD profile over the discharge operation while in a presence of an EMI event.

First claim

What is claimed is:

1. A system, comprising:
a plurality of electrodes positioned within a patient, the plurality of electrodes including an active electrode, the active electrode configured to be a cathode electrode located proximate to tissue of interest that is associated with a target region;
an anode electrode;
an antenna;
a control circuit configured to control delivery of a therapy during a therapy delivery interval, the therapy to be delivered between the anode electrode and the active electrode, the system developing a residual charge between the anode electrode and the active electrode over the therapy delivery interval;
a regulator circuit connected to the cathode electrode, the regulator circuit configured to control at least one of voltage or current at the cathode electrodes;
during a discharge operation, the control circuit configured to manage the CR circuit to control at least one of a discharge voltage or current over the discharge operation to discharge the residual charge after therapy delivery in a manner that follows an actively emulated passive discharge (AEPD) profile; and
during the discharge operation, the regulator circuit configured to regulate at least one of the discharge voltage or current through the active electrode based on an electromagnetic interference (EMI) feedback signal, to maintain the AEPD profile over the discharge operation while in a presence of an EMI event.

2. The system of claim 1 , wherein the antenna is an EMI antenna is configured to generate the EMI feedback signal indicative of a voltage interference induced at least in part by an electromagnetic field surrounding the system.

3. The system of claim 1 , wherein the antenna includes at least one of: i) an inactive electrode, and ii) a non-electrode wire within a lead or routed with insulation substantially alongside the outside of the lead, having the array of electrodes provided at a distal end of a lead.

4. The system of claim 1 , further comprising a reference voltage source configured to supply a reference voltage as a second input to the regulator circuit, the regulator circuit configured to regulate at least one of the discharge voltage or current through the active and anode electrodes based on a difference between the EMI feedback signal and the reference voltage.

5. The system of claim 1 , wherein the regulator circuit comprises an error amplifier and a transistor, the error amplifier configured to hold the EMI feedback signal at a reference voltage and provide an output based thereon, the transistor configured to regulate the current flow through the active and anode electrodes based on the output of the error amplifier to maintain the AEPD profile while in the presence of the EMI event.

6. The system of claim 1 , wherein the antenna includes an inactive electrode, and wherein the inactive electrode and the active electrode are configured to have substantially similar electrical properties.

7. The system of claim 1 , further comprising a lead having a distal end that includes the plurality of electrodes, the antenna including a non-electrode wire within the lead or a wire routed with insulation substantially alongside the outside of the lead.

8. The system of claim 1 , wherein the antenna is configured to sense and mitigate interference from EMI.

9. The system of claim 1 , wherein the control circuit is configured to deliver a neurostimulation (NS) therapy as the therapy.

10. The system of claim 1 , wherein the regulator circuit is configured to modulate the current flow over the discharge operation, based on the EMI feedback signal, in order to follow the AEPD profile to compensate for voltage fluctuation caused by the EMI event.

11. A method, comprising:
providing a plurality of electrodes to be located proximate to tissue of interest that is associated with a target region, the plurality of electrodes including an active electrode configured to be a cathode electrode;
delivering a therapy during a therapy delivery interval between an anode electrode and the active electrode, the system developing a residual charge between the anode electrode and the active electrode over the therapy delivery interval; and
during a discharge operation in a presence of an EMI event:
controlling at least one of a discharge voltage or current over the discharge operation to discharge the residual charge after therapy delivery in a manner that follows an actively emulated passive discharge (AEPD) profile;
obtaining an electromagnetic interference (EMI) feedback signal from an antenna while in the presence of the EMI event; and
regulating the at least one of a discharge voltage or current at the anode and cathode electrodes based on the EMI feedback signal to maintain the AEPD profile over the discharge operation while in the presence of the EMI event.

12. The method of claim 11 , wherein the EMI feedback signal is indicative of a voltage interference induced at least in part by an electromagnetic field surrounding the system.

13. The method of claim 12 , wherein the voltage gradient is induced between the antenna and the anode electrode.

14. The method of claim 11 , further comprising supplying a reference voltage, and regulating the current flow based on a difference between the EMI feedback signal and the reference voltage.

15. The method of claim 11 , wherein the controlling operation further comprises:
utilizing a regulator circuit that comprises an error amplifier and a transistor;
comparing the EMI feedback signal to a reference voltage at the error amplifier and provide an output based thereon; and
utilizing the transistor to regulate the discharge current flow through the anode and cathode electrodes based on the output of the error amplifier to maintain the AEPD profile while in the presence of the EMI event.

16. The method of claim 11 , further comprising utilizing an inactive electrode as the antenna and configuring the inactive electrode and the active electrode to have substantially similar electrical properties.

17. The method of claim 11 , further comprising implanting a lead having a distal end that includes the plurality of electrodes and utilizing a non-electrode wire within the lead or a wire routed with insulation substantially alongside an outside of the lead as the EMI antenna.

18. The method of claim 11 , further comprising implanting an implantable pulse generator that houses a control circuit and current regulator (CR) circuit that deliver a neurostimulation (NS) therapy as the therapy.

19. The method of claim 18 , wherein the delivering operation further comprises delivering the NS therapy repeatedly over successive therapy delivery intervals that are separated by corresponding successive discharge operations while in the presence of the EMI event.

20. The method of claim 19 , wherein the regulating operation further comprises compensating for voltage fluctuation caused by the EMI event by modulating the discharge current flow over the discharge operation, based on the EMI feedback signal, in order to follow the AEPD profile.

Assignees

• Advanced Neuromodulation Systems Inc

Inventors

• Boor Steven
• Deshazo Daran

Classifications

• A61N1/36071 Primary

  Pain · CPC title

• A61N1/08

  Arrangements or circuits for monitoring, protecting, controlling or indicating {(for external stimulators A61N1/3603; for implantable neurostimulators A61N1/36128; for heart stimulators A61N1/37; for defibrillators A61N1/3925)} · CPC title

• A61N1/0452

  Specially adapted for transcutaneous muscle stimulation [TMS] · CPC title

• A61N1/0456

  Specially adapted for transcutaneous electrical nerve stimulation [TENS] · CPC title

• A61N1/0534

  Electrodes for deep brain stimulation · CPC title