Magnetic Stimulation Devices and Methods of Therapy

• US 20110125203A1
• Filed: 12/09/2010
• Published: 05/26/2011
• Est. Priority Date: 03/20/2009
• Status: Abandoned Application

• Current Assignee: Electrocore, Llc
• Original Assignee: Electrocore, Llc
• Inventors: Simon, Bruce, Raffle, John T., Errico, Joseph P.
• Application Number:
  US12/964,050
• Publication Number:
  US 20110125203A1
• Time in Patent Office: Days
• US Class Current: 607/2
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/40 Applying electric fields by inductive or capacitive coupling microwave apparatus A61N5/00; Applying radio-frequency signals
• CPC Class Codes: A61N 2/006 for magnetic stimulation of nerve tissue
• CPC Class Codes: A61N 2/02 using magnetic fields produced by coils, including single turn loops or electromagnets A61N2/12 takes precedence

Abstract

Devices and systems are disclosed for the non-invasive treatment of medical conditions through delivery of energy to target tissue, comprising a source of electrical power, a magnetically permeable toroidal core, and a coil that is wound around the core. The coil and core are embedded in a continuous electrically conducting medium, which is adapted to have a shape that conforms to the contour of an arbitrarily oriented target body surface of a patient. The conducting medium is applied to that surface by any of several disclosed methods, and the source of power supplies a pulse of electric charge to the coil, such that the coil induces an electric current and/or an electric field within the patient, thereby stimulating tissue and/or one or more nerve fibers within the patient. The invention shapes an elongated electric field of effect that can be oriented parallel to a long nerve. In one embodiment, the device comprises two toroidal cores that lie adjacent to one another.

Claims

1. An apparatus for applying energy transcutaneously to a target region within a patient comprising:

a source of energy for generating a magnetic field that is located essentially entirely exterior to an outer skin surface of the patient;

a conduction medium through which an electrical current induced by the magnetic field penetrates the outer skin surface of the patient; and

wherein the source of energy and the conduction medium are configured to shape the electrical field that is induced by the magnetic field, such that energy from the induced electric field and/or induced current is sufficient to modulate a nerve at the target region.

2. The apparatus of claim 1 wherein the source of energy comprises a source of electrical energy coupled to a coil housed within an enclosure;

the enclosure being configured to contain the magnetic field therein.

3. The apparatus of claim 1 wherein the source of energy and the conduction medium are configured to orient the electric field substantially parallel with the nerve at the target region.

4. The apparatus of claim 1 wherein the source of energy comprises a source of electrical energy coupled to first and second coils configured to generate first and second time-varying magnetic fields;

each coil being housed within an enclosure configured to substantially confine the magnetic field therein.

5. The apparatus of claim 4 wherein the first and second coils are toroidal and wherein the first coil is configured to orient the first magnetic field in a first direction around the first toroid and the second coil is configured to orient the second magnetic field in a second direction around the second solenoid, and wherein the first and second directions are opposite.

6. The apparatus of claim 5 wherein holes of the first and second toroids are oriented essentially parallel to the outer skin surface of the tissue.

7. The apparatus of claim 2 further comprising an electrical conductor/non-conductor boundary configured to at least partially constrain the direction of the electric field.

8. The apparatus of claim 2 wherein the conduction medium is positioned in electrical contact to a portion of an outside surface of the enclosure to at least partially restrict the direction of the electric field.

9. The apparatus of claim 1 wherein the target region is a nerve located at least 1-2 cm beyond the outer skin surface.

10. The apparatus of claim 1 where the target region is a nerve is located at least 2-5 cm beyond the outer skin surface.

11. The apparatus of claim 1 wherein the electrical field has an amplitude of greater than 10 V/m.

12. The apparatus of claim 1 wherein the electrical field has a gradient of greater than 2 V/m/mm.

13. The apparatus of claim 1 wherein the electrical field comprises bursts of pulses with a frequency of about 5 Hz to about 100 Hz.

14. The apparatus of claim 1 wherein the electrical field comprises bursts of between 1 and 20 pulses with each pulse about 50-1000 microseconds in duration.

15. The apparatus of claim 4 further comprising an outer enclosure wherein the conduction medium comprises an electrically conductive fluid housed within the outer enclosure and at least partially surrounding the first and second coils.

16. The apparatus of claim 15 wherein the electrically conductive medium comprises a solution of electrolytes.

17. The apparatus of claim 15 wherein the electrically conductive fluid comprises a conductive gel.

18. The apparatus of claim 15 wherein at least a portion of the outer enclosure comprises material that is permeable to charged particles.

19. The apparatus of claim 18 wherein the portion of the outer enclosure comprises an ion-permeable material.

20. A device for modulating one or more nerves within a body of a patient comprising:

a source of energy configured to apply an electrical impulse transcutaneously through an outer skin surface of the patient to a nerve at a target region below the outer skin surface; and

wherein the electrical impulse is sufficient to modulate a nerve within the target region and insufficient to substantially modulate nerve(s) in the vicinity of the outer skin surface.

21. The device of claim 20 wherein the electrical impulse is sufficient to modulate the nerve at least approximately 1-2 cm below the outer skin surface.

22. The device of claim 20 wherein the source of energy comprises a source of electrical energy coupled to first and second coils configured to generate first and second magnetic fields;

each coil being housed within an enclosure configured to substantially confine the magnetic field therein.

23. The device of claim 22 wherein the first and second coils are toroidal and wherein the first coil is configured to orient the first magnetic field in a first direction around the first toroid and the second coil is configured to orient the second magnetic field in a second direction around the second solenoid, and wherein the first and second directions are opposite.

24. A method for selectively applying energy to a target region within a patient comprising:

generating a time-varying magnetic field that is located essentially entirely outside of the patient;

shaping an electric field that is induced by said magnetic field; and

conducting an electric current that is induced by said magnetic field through an outer skin surface of the patient to the target region to modulate a nerve at the target region.

25. The method of claim 24 wherein the target region is a nerve at least approximately 1-2 cm below the outer skin surface.

26. The method of claim 24 wherein the target region is a nerve approximately 2-5 cm below the outer skin surface.

27. The method of claim 24 further comprising substantially constraining the electric current from modulating one or more nerves in a second region between the outer skin surface and the target region.

28. The method of claim 24 wherein the generating step comprises generating the time-varying magnetic field within an enclosed coil.

29. The method of claim 28 wherein the shaping step comprises generating a second time-varying magnetic field within a second enclosed coil positioned near or adjacent to the first enclosed coil.

30. The method of claim 28 wherein the shaping step comprises positioning a conducting medium around a portion of the enclosed coil such that the direction of the electrical field is constrained within the conducting medium.

31. The method of claim 28 wherein the shaping step comprises positioning an electrical insulator around a portion of the enclosed coil such that the component of the induced electric field normal to the surface of the insulator is zero.

32. The method of claim 24 wherein the conducting step is carried out by electrically coupling the induced electric field to the target region allowing current to flow through the outer skin surface of the patient.

33. A device for applying a time varying therapeutic electric field within a tissue comprising:

at least two toroidal coil elements configured to create an electric field outside of the coil elements; and

a conduit having a first end and a second end and containing a conductive medium, wherein said first and second ends of said conduit comprise conductive surfaces for passing an electrical current produced by the electric field through the surface of the tissue.

34. The device as set forth in claim 33 further comprising a source of energy for producing a magnetic field in each of the toroidal coil elements.

35. The device of claim 34 wherein at least one of said magnetic fields is oriented in a first direction around one of the toroidal coil elements, and at least one of said magnetic fields is oriented in a second direction around another of said toroidal coil elements;

wherein the first direction is opposite the second direction.

36. The device as set forth in claim 33, wherein the holes of at least two said toroidal coil elements are oriented parallel relative to the surface of the tissue.

37. The device as set forth in claim 36, further comprising a second conduit containing an electrically conductive medium extending from the first end to the second end of said first conduit, wherein said electrically conductive medium of said second conduit is in selectively positionable electrical contact with the electrically conductive medium of the first conduit.

38. The device as set forth in claim 33, wherein the holes of at least two said toroidal coil elements are oriented perpendicular relative to the surface of the tissue.

39. A device for directing a therapeutic electric current in tissue comprising:

at least two elements within an enclosure, each configured to generate a time-varying magnetic field fully contained within the enclosure and each configured to generate a time-varying electric field;

a conduit containing a conductive medium located outside of the at least two elements, said conducting medium configured to contact the tissue at two spatially distinct locations; and

wherein said conduit is positioned relative to the at least two elements such that the time-varying electric fields drive a current through the conductive medium and through the tissue.

40. The device of claim 39 wherein the elements are toroidal coil elements.

41. A therapeutic device for applying an electric field to a region of tissue, comprising:

a plurality of first elements, each of said first elements producing therein a time-varying magnetic field, said magnetic fields each being fully contained within said first elements; and

a second element containing a conductive medium positioned relative to the first elements such that an electric field is induced in said conductive medium by the magnetic field in each of said first elements.

42. The device of claim 41 further comprising first and second conductive interfacing elements disposed at different positions on the surface of said second element, said interfacing elements being positioned to carry electrical current to and from said conductive medium, such that contact between the interfacing elements and tissue permits induced electrical current to flow through the tissue.

43. A device for applying a therapeutic electric signal to tissue, comprising:

a first element containing a time-varying magnetic field;

a volume of conductive medium;

a non-conductive housing element containing said first element and the volume of conductive medium; and

a pair of electrically conductive ports in said housing, positionable against the tissue and configured to allow electric current to flow between the volume of conductive medium and the tissue, through the ports.

44. The device of claim 43 wherein the conductive medium is contained within the non-conductive housing such that current induced by the first element cannot flow solely within the non-conductive housing when the ports are positioned against the tissue.

45. A device for applying a therapeutic electric signal to a target region within a patient'"'"'s body comprising:

at least two first elements, each containing a time-varying magnetic field;

a non-conductive housing element containing each of the first elements and a volume of electrically conductive medium;

a pair of electrically conductive ports in said housing, positionable against tissue of the patient'"'"'s body and configured to allow electric current to flow between the volume of conductive medium and the tissue, through the ports; and

wherein each of said first elements is positionable relative the tissue such that electrical fields induced by the magnetic fields penetrate into said tissue and such that current cannot flow solely within said housing.

46. A device for applying a therapeutic electric signal to a target region within a patient'"'"'s body, comprising:

a first element containing a time-varying magnetic field;

a non-conductive housing containing the first element that is positionable in close proximity to an outer skin surface of the patient'"'"'s body such that an electric field induced by said time-varying magnetic field exists beneath the outer skin surface;

a volume of conductive medium constrained by the non-conductive housing to have a shape that may be other than a half-plane; and

one or more electrically conductive ports in the non-conductive housing, positionable against the outer skin surface and configured to allow electric current to flow between the volume of conductive medium and the target region, through the outer skin surface.