Shielded stimulation and sensing system and method

• US 20110282179A1
• Filed: 10/06/2009
• Published: 11/17/2011
• Est. Priority Date: 11/13/2008
• Status: Active Grant

• Current Assignee: Proteus Digital Health, Inc. (Otsuka Holdings Company Limited)
• Original Assignee: Proteus Biomedical, Inc. (Otsuka Holdings Company Limited)
• Inventors: Zdeblick, Mark
• Granted Patent: US 8,644,919 B2
• Time in Patent Office: Days
• US Class Current: 600/393
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/0534 Electrodes for deep brain stimulation
• CPC Class Codes: A61N 1/0553 Paddle shaped electrodes, e.g. for laminotomy
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration

Abstract

Spatial arrays of electrodes are provided, each array in a region of tissue. The electrodes of an array are connected so that some of the electrodes serve as shield electrodes relative to a pair of electrodes used for pulse stimulation or sensing of electrical activity, or both. The shield electrodes are connected together, defining an electrical node, the node defining a stable potential in predetermined relationship with power supply levels or with reference voltages for sensing circuitry. Multiplexing techniques may be employed so that sensed activity at each of several electrode locations can be communicated to electronics external to the electrode locations.

Claims

1. A method for applying an electrical pulse to, or for sensing electrical activity at, a first region of tissue in an animal, the method comprising the steps of:

providing at the first region of tissue a first array of electrodes disposed upon a respective surface, the first array comprising respective first and second electrodes disposed upon the respective surface, the first array further comprising a plurality of respective third electrodes also disposed upon the respective surface and surrounding the respective first and second electrodes;

wherein the first array of electrodes is electrically selectively connected via a lead to electronics located external to the first array of electrodes, the lead comprising at least one electrical conductor;

the selective connections of the electrodes comprising sensing or driving circuitry connecting the first and second electrodes with the at least one electrical conductor, and further comprising circuitry disposing the third electrodes to serve as an electrical shield for the first and second electrodes through conductive coupling with tissue nearby thereto.

2. The method of claim 1 wherein the method applies an electrical pulse to the first region of tissue, and wherein the selective connections of the electrodes comprises driving circuitry.

3. The method of claim 1 wherein the method senses electrical activity at the first region of tissue, and wherein the selective connections of the electrodes comprises sensing circuitry.

4. The method of claim 1 wherein the sensing circuitry comprises a differential amplifier receiving the first and second electrodes as inputs, and providing an output to the at least one electrical conductor, whereby sensed electrical activity is communicated to the electronics external to the array of electrodes.

5. The method of claim 1 wherein the respective surface is substantially planar.

6. The method of claim 1 wherein the respective surface is convex.

7. The method of claim 1 wherein the number of third electrodes is at least six.

8. The method of claim 7 wherein the number of third electrodes is ten.

9. The method of claim 1 wherein the first array receives positive and negative power supplies, and wherein the circuitry selectively connecting the third electrodes to the at least one electrical conductor comprises circuitry biasing the third electrodes at a stable voltage between the positive and negative power supplies.

10. The method of claim 9 wherein the circuitry selectively connecting the third electrodes to the at least one electrical conductor establishes the stable voltage between the positive and negative power supplies at least a diode drop away from either of the power supplies.

11. The method of claim 10 wherein the circuitry selectively connecting the electrodes defines a substrate, and wherein the substrate has a potential, and wherein the circuitry selectively connecting the third electrodes to the at least one electrical conductor further establishes the stable voltage at least two diode drops away from the potential of the substrate.

12. The method of claim 3 wherein the sensed electrical activity as voltage is converted to current, the current thereby carried on the at least one electrical conductor to the electronics, the electronics disposed to measure the current.

13. The method of claim 3 wherein the sensed electrical activity as voltage is converted to a digital signal, the digital signal thereby carried on the at least one electrical conductor to the electronics, the electronics disposed to detect the digital signal.

14. The method of claim 13 wherein the carriage of the digital signal on the at least one electrical conductor is performed by means of an envelope modulation.

15. The method of claim 1 wherein the method further applies an electrical pulse to, or senses electrical activity at, a second region of tissue in the animal, the method further comprising the steps of:

providing at the second region of tissue a second array of electrodes disposed upon a respective surface, the second array comprising respective first and second electrodes disposed upon the respective surface, the second array further comprising a plurality of respective third electrodes also disposed upon the respective surface and surrounding the first and second electrodes;

wherein the second array of electrodes is electrically selectively connected via the lead to the electronics located external to the first array of electrodes, the electronics located external to the first array of electrodes also located external to the second array of electrodes;

the selective connections of the electrodes comprising sensing or driving circuitry connecting the first and second electrodes with the at least one electrical conductor, and further comprising circuitry disposing the third electrodes to serve as an electrical shield for the first and second electrodes through conductive coupling with tissue nearby thereto;

the method comprising addressing the selective connections of the first array and addressing the selective connections of the second array so that the electronics external to the first and second arrays of electrodes are in multiplexed communication therewith.

16. The method of claim 15 wherein the multiplexing is by means of an approach selected from the set consisting of time-domain multiplexing and frequency-domain multiplexing.

49. The apparatus of claim 15 wherein the multiplexing is by means of an approach selected from the set consisting of time-domain multiplexing and frequency-domain multiplexing.

17. A method for using an array of multiplexed electrodes for applying an electrical pulse to, or for sensing electrical activity at, a region of tissue in an animal, the method comprising the steps of:

providing at the first region of tissue a first array of multiplexed electrodes disposed upon a respective surface and in electrical contact with surrounding tissue,

whereby said multiplexing comprises enabling each electrode to be either electrically isolated, connected to at least one conductor within the lead, or connected to a floating node connected to other electrodes in the array.

18. The method of claim 17 wherein the multiplexing further comprises enabling each electrode to be electrically connected to at least one input of a sensing circuit.

19. The method of claim 17 wherein the multiplexing further comprises enabling each electrode to be electrically connected to a current source.

20. The method of claim 17 wherein at least one electrode that is enabled to the floating node is adjacent to at least one electrode that is enabled to a conductor in the lead.

21. The method of claim 17 wherein at least one electrode that is enabled to the floating node is adjacent to at least one electrode that is enabled to an input of a sensing circuit.

22. The method of claim 17 wherein whereby a first electrode is enabled to a first conductor in the lead and a second electrode is enabled to a second conductor in the lead and at least two additional electrodes on the surface are enabled to the floating node.

23. The method of claim 17 wherein the floating node is capacitively coupled to at least one conductor in the lead.

24. The method of claim 17 wherein the floating node is capacitively coupled to two conductors in the lead using two substantially equivalent capacitors.

25. The method of claim 17 wherein the floating node is electrically connected to at least one conductor in the lead and that conductor is electrically isolated from the drive circuitry.

26. The method of claim 17, further comprising providing at least one additional array of multiplexed electrodes at least one additional region of tissue, said additional array being substantially similar to the first array except for a different electrical address.

27. The method of claim 17 wherein the floating node is biased to be at least one diode drop away from sensor supply voltages.

28. The method of claim 17 wherein a medical carrier comprises multiple such arrays connected to said at least one conductor in the lead.

29. A method for using an array of electrodes for sensing electrical activity at a region of tissue in an animal, the method comprising the steps of:

providing at the first region of tissue a first array of electrodes disposed upon a respective surface and in electrical contact with surrounding tissue,

providing means for connecting at least a first electrode to a sensing circuit, means for connecting at least a second electrode to a second input to the sensing circuit, and at least a third electrode to a floating node, the at least a third electrode defining one or more floating electrodes.

30. The method of claim 29 wherein the method further comprises a step of first sampling a differential voltage at the sensing circuit between the first electrode and the second electrode;

storing a first value indicative of that first voltage;

enabling the floating electrodes to be connected to the floating node, the floating node connected to a bias network, said bias network biasing the floating nodes to be at least one diode drop away from either voltage supplied to the sensing circuit;

storing a second value representing a second measured voltage.

31. The method of claim 29 wherein the sensing circuit subtracts the first value from the second value and stores the result as a third value.

32. The method of claim 29 wherein at least one of the stored values is transmitted to an attached controller using conductors in the lead.

33. The method of claim 29 wherein a medical carrier comprises multiple such arrays connected to said conductors in the lead.

34. Apparatus for applying an electrical pulse to, or for sensing electrical activity at, a first region of tissue in an animal, the apparatus comprising:

a first array of electrodes disposed upon a respective surface, the first array comprising respective first and second electrodes disposed upon the respective surface, the first array further comprising a plurality of respective third electrodes also disposed upon the respective surface and surrounding the respective first and second electrodes;

wherein the first array of electrodes is electrically selectively connected via a lead to electronics located external to the first array of electrodes, the lead comprising at least one electrical conductor;

the selective connections of the electrodes comprising sensing or driving circuitry connecting the first and second electrodes with the at least one electrical conductor, and further comprising circuitry disposing the third electrodes to serve as an electrical shield for the first and second electrodes through conductive coupling with tissue nearby thereto.

35. The apparatus of claim 34 wherein the selective connections of the electrodes comprises driving circuitry.

36. The apparatus of claim 34 wherein the selective connections of the electrodes comprises sensing circuitry.

37. The apparatus of claim 34 wherein the sensing circuitry comprises a differential amplifier receiving the first and second electrodes as inputs, and providing an output to the at least one electrical conductor, whereby sensed electrical activity is communicated to the electronics external to the array of electrodes.

38. The apparatus of claim 34 wherein the respective surface is substantially planar.

39. The apparatus of claim 34 wherein the respective surface is convex.

40. The apparatus of claim 34 wherein the number of third electrodes is at least six.

41. The apparatus of claim 40 wherein the number of third electrodes is ten.

42. The apparatus of claim 34 wherein the first array receives positive and negative power supplies, and wherein the circuitry selectively connecting the third electrodes to the at least one electrical conductor comprises circuitry biasing the third electrodes at a stable voltage between the positive and negative power supplies.

43. The apparatus of claim 42 wherein the circuitry selectively connecting the third electrodes to the at least one electrical conductor establishes the stable voltage between the positive and negative power supplies at least a diode drop away from either of the power supplies.

44. The apparatus of claim 43 wherein the circuitry selectively connecting the electrodes defines a substrate, and wherein the substrate has a potential, and wherein the circuitry selectively connecting the third electrodes to the at least one electrical conductor further establishes the stable voltage at least two diode drops away from the potential of the substrate.

45. The apparatus of claim 36 wherein the sensed electrical activity as voltage is converted to current, the current thereby carried on the at least one electrical conductor to the electronics, the electronics disposed to measure the current.

46. The apparatus of claim 36 wherein the sensed electrical activity as voltage is converted to a digital signal, the digital signal thereby carried on the at least one electrical conductor to the electronics, the electronics disposed to detect the digital signal.

47. The apparatus of claim 46 wherein the carriage of the digital signal on the at least one electrical conductor is performed by means of an envelope modulation.

48. The apparatus of claim 34 further comprising a second array of electrodes disposed upon a respective surface, the second array comprising respective first and second electrodes disposed upon the respective surface, the second array further comprising a plurality of respective third electrodes also disposed upon the respective surface and surrounding the first and second electrodes;

wherein the second array of electrodes is electrically selectively connected via the lead to the electronics located external to the first array of electrodes, the electronics located external to the first array of electrodes also located external to the second array of electrodes;

the selective connections of the electrodes comprising sensing or driving circuitry connecting the first and second electrodes with the at least one electrical conductor, and further comprising circuitry disposing the third electrodes to serve as an electrical shield for the first and second electrodes through conductive coupling with tissue nearby thereto.

50. Apparatus for using an array of multiplexed electrodes for applying an electrical pulse to, or for sensing electrical activity at, a region of tissue in an animal, the apparatus comprising:

a first array of multiplexed electrodes disposed upon a respective surface and in electrical contact with surrounding tissue;

wherein said multiplexing comprises enabling each electrode to be either electrically isolated, connected to at least one conductor within the lead, or connected to a floating node connected to other electrodes in the array.

51. The apparatus of claim 50 wherein the multiplexing further comprises enabling each electrode to be electrically connected to at least one input of a sensing circuit.

52. The apparatus of claim 50 wherein the multiplexing further comprises enabling each electrode to be electrically connected to a current source.

53. The apparatus of claim 50 wherein at least one electrode that is enabled to the floating node is adjacent to at least one electrode that is enabled to a conductor in the lead.

54. The apparatus of claim 50 wherein at least one electrode that is enabled to the floating node is adjacent to at least one electrode that is enabled to an input of a sensing circuit.

55. The apparatus of claim 50 wherein whereby a first electrode is enabled to a first conductor in the lead and a second electrode is enabled to a second conductor in the lead and at least two additional electrodes on the surface are enabled to the floating node.

56. The apparatus of claim 50 wherein the floating node is capacitively coupled to at least one conductor in the lead.

57. The apparatus of claim 50 wherein the floating node is capacitively coupled to two conductors in the lead using two substantially equivalent capacitors.

58. The apparatus of claim 50 wherein the floating node is electrically connected to at least one conductor in the lead and that conductor is electrically isolated from the drive circuitry.

59. The apparatus of claim 50 further comprising at least one additional array of multiplexed electrodes at least one additional region of tissue, said additional array being substantially similar to the first array except for a different electrical address.

60. The apparatus of claim 50 wherein the floating node is biased to be at least one diode drop away from sensor supply voltages.

61. The apparatus of claim 50 wherein a medical carrier comprises multiple such arrays connected to said at least one conductor in the lead.

62. Apparatus for using an array of electrodes for sensing electrical activity at a region of tissue in an animal, the apparatus comprising:

a first array of electrodes disposed upon a respective surface and in electrical contact with surrounding tissue,

means for connecting at least a first electrode to a sensing circuit, means for connecting at least a second electrode to a second input to the sensing circuit, and at least a third electrode to a floating node, the at least a third electrode defining one or more floating electrodes.

63. The apparatus of claim 62 wherein the sensing circuit subtracts the first value from the second value and stores the result as a third value.

64. The apparatus of claim 62 wherein at least one of the stored values is transmitted to an attached controller using conductors in the lead.

65. The apparatus of claim 62 wherein a medical carrier comprises multiple such arrays connected to said conductors in the lead.

66. A method for use with a lead having an array comprising a multiplicity of electrodes, the lead having been implanted into animal tissue, the method comprising the steps of:

selecting first electrodes from the array for use to sense or stimulate, and selecting second shield electrodes from the array connected to a floating node;

observing phenomena relating to the animal and noting the phenomena observed in connection with the selected electrodes;

selecting third electrodes from the array for use to sense or stimulate, and selecting fourth shield electrodes from the array connected to a floating node;

observing phenomena relating to the animal and noting the phenomena observed in connection with the selected electrodes;

configuring the lead to employ the third and fourth selected electrodes for some interval thereafter, and during the interval, carrying out sensing or stimulation.

67. The method of claim 66 wherein the tissue is neural tissue.

68. The method of claim 67 wherein the animal has Parkinson'"'"'s disease.