Apparatus and methods for applying neural stimulation to a patient

• US 20050070971A1
• Filed: 08/02/2004
• Published: 03/31/2005
• Est. Priority Date: 08/01/2003
• Status: Active Grant

• Current Assignee: Advanced Neuromodulation Systems Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Advanced Neuromodulation Systems Incorporated (Abbott Laboratories Incorporated)
• Inventors: Fowler, Brad, Gliner, Bradford Evan
• Granted Patent: US 7,684,866 B2
• Time in Patent Office: Days
• US Class Current: 607/45
• CPC Class Codes: A61N 1/0531 Brain cortex electrodes
• CPC Class Codes: A61N 1/0539 Anchoring of brain electrode systems, e.g. within burr hole
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease

Abstract

Systems and methods for neural stimulation may include a stimulus unit; a first electrode assembly having a first set of contacts; and a second set of contacts. The stimulus unit can be an implantable pulse generator including a first terminal that can be biased at a first signal polarity and a second terminal that can be biased at a second signal polarity. The first electrode assembly includes a support member configured to be placed at the stimulation site, the first set of contacts carried by the support member, and a first lead configured to be attached to the first terminal of the implantable pulse generator for biasing the surface contacts at the first polarity. The second set of contacts is detached from the surface electrode assembly. The second set of contacts can be one or more conductive elements fixed to or forming portions of the implantable pulse generator, or a separate electrode array.

Claims

1. A system for applying electrical stimulation to a cortical stimulation site proximate to the surface of the cortex of a patient, the system comprising:

a stimulus unit having a pulse system including a first terminal that can be biased at a first polarity and a second terminal that can be biased at a second polarity;

a surface electrode assembly having a support member configured to be implanted in the patient at the stimulation site, a plurality of surface contacts carried by the support member, and a first lead attached to the surface contacts, wherein the first lead is configured to be attached to the first terminal of the pulse system for biasing the surface contacts at the first polarity; and

a return contact detached from the surface electrode assembly and configured to be coupled to the second terminal of the pulse system to be biased at the second polarity, wherein the return contact is configured to be spaced apart from the stimulation site in operation.

2. The system of claim 1 wherein the surface electrode assembly has only a single row of surface contacts.

3. The system of claim 1 wherein the surface electrode assembly comprises a plurality of rows of surface contacts and the first lead is electrically coupled to a plurality of the surface contacts in at least one of the rows.

4. The system of claim 1 wherein:

the stimulus unit is an implantable pulse generator comprising a housing, the pulse system in the housing, and a controller in the housing; and

the return contact is attached to the implantable pulse generator.

5. The system of claim 1 wherein:

the stimulus unit is an implantable pulse generator comprising a housing having an electrically conductive section, the pulse system and a controller, and wherein the pulse system and the controller are carried by the housing; and

the return contact is at least a portion of the electrically conductive section of the housing that is electrically coupled to the second terminal to be biased at the second polarity.

6. The system of claim 1 wherein the return contact is a component of a return contact assembly comprising a support base that carries the return contact and a second lead attached to the return contact, the support base being detached from the support member of the surface electrode assembly, and the second lead being configured to be attached to the second terminal of the implantable pulse generator for biasing the return contact at the second polarity.

7. The system of claim 6 wherein the return contact assembly comprises a plurality of return contacts carried by the support base.

8. The system of claim 1 wherein:

the first lead is attached to the first terminal of the pulse system;

the return contact is attached to a second lead, and the second lead is attached to the second terminal of the pulse generator; and

the first terminal provides an anodal potential and the second terminal provides a cathodal potential.

9. The system of claim 1 wherein:

the first lead is attached to the first terminal of the pulse system;

the return contact is attached to a second lead, and the second lead is attached to the second terminal of the pulse generator; and

the first terminal provides a cathodal potential and the second terminal provides an anodal potential.

10. The system of claim 1 wherein:

the stimulus unit is an implantable pulse generator configured to be implanted in a human being, and the stimulus unit further comprises a controller operatively coupled to the pulse system, and the controller includes a programmable medium; and

the programmable medium contains instructions that cause the pulse system to concurrently electrically bias the surface contact at the stimulation site at the first polarity while biasing the return contact at a return site spaced apart from the stimulation site at the second polarity for a unipolar stimulation period.

11. The system of claim 1 wherein:

the stimulus unit is an implantable pulse generator configured to be implanted in a human being, and the stimulus unit further comprises a controller operatively coupled to the pulse system, and the controller includes a programmable medium; and

the programmable medium contains instructions that cause the pulse system to concurrently electrically bias the surface contact at the stimulation site at the first polarity while biasing the return contact at the second polarity for a unipolar stimulation period to generate an electrical field extending site through deep layers of the cortex in a direction generally normal with respect to the surface contact at the stimulation site.

12. The system of claim 1 wherein:

the stimulus unit is an implantable pulse generator configured to be implanted in a human being, and the stimulus unit further comprises a controller operatively coupled to the pulse system, and the controller includes a programmable medium; and

the programmable medium contains instructions that cause the pulse system to concurrently electrically bias the surface contact at the stimulation site at the first polarity while biasing the return contact at the second polarity for a unipolar stimulation period to generate an electrical field extending through deep layers of the cortex running generally perpendicular to a cortical layer structure.

13. A system for applying electrical stimulation to a cortical stimulation site, comprising:

an implantable pulse generator having a first terminal configured to be biased at a first polarity and a second terminal configured to be biased at a second polarity;

a cortical electrode assembly having a plurality of surface contacts configured to be implanted at least substantially proximate to a surface layer of the cortex at the stimulation site, wherein the surface contacts are electrically coupled to the first terminal of the implantable pulse generator; and

a return contact that is not attached to the cortical electrode assembly, the return contact being movable with respect to the surface contact and configured to be attached to the patient at a return location spaced apart from the stimulation site.

14. The system of claim 13 wherein the cortical electrode assembly comprises a plurality of rows of the surface contacts, and the surface contacts are electrically coupled to the first terminal of the implantable pulse generator to be biased at the first polarity.

15. The system of claim 13 wherein:

the implantable pulse generator further comprises a housing, a pulse system in the housing, and a controller in the housing; and

the return contact is attached to the implantable pulse generator.

16. The system of claim 13 wherein:

the implantable pulse generator further comprises a housing having an electrically conductive section, a pulse system carried by the housing, and a controller carried by the housing, and wherein the electrically conductive section of the housing is electrically coupled to the second terminal; and

the return contact comprises the electrically conductive section of the housing.

17. The system of claim 13 wherein the return contact is a component of a return contact assembly comprising a support base that carries the return contact, the support base being detached from the cortical electrode assembly;

and the return contact is coupled to the second terminal of the pulse generator to be biased at the second polarity.

18. The system of claim 17 wherein the return contact assembly comprises a plurality of return contacts carried by the support base.

19. The system of claim 13 wherein:

the implantable pulse generator further comprises a pulse system and a controller operatively coupled to the pulse system, wherein the controller includes a programmable medium; and

the programmable medium contains instructions that cause the pulse system to concurrently electrically bias the surface contact at the stimulation site at the first polarity while biasing the return contact at the second polarity for a unipolar stimulation period to generate an electrical field extending through deep layers of the cortex in a direction generally normal with respect to the surface contact at the stimulation site.

20. The system of claim 13 wherein:

the implantable pulse generator further comprises a pulse system and a controller operatively coupled to the pulse system, wherein the controller includes a programmable medium; and

the programmable medium contains instructions that cause the pulse system to concurrently electrically bias the surface contact at the stimulation site at the first polarity while biasing the return contact at the second polarity for a unipolar stimulation period to generate an electrical field extending through deep layers of the cortex running generally in a direction generally perpendicular to a cortical layer structure.

21. A system for applying electrical stimulation to a cortical stimulation site, comprising:

an implantable pulse generator having a first terminal configured to be biased at a first polarity and a second terminal configured to be biased at a second polarity;

a cortical electrode assembly having a support member and a plurality of first surface contacts carried by the support member, wherein the first surface contacts are electrically coupled to the first terminal of the implantable pulse generator to be biased at the first polarity; and

a return electrode assembly having a support base and a return contact carried by the support base, wherein the support base is not attached to the support member so that the support base is attachable to the patient at a return location separate from the stimulation site, and wherein the return contact is electrically coupled to the second terminal of the implantable pulse generator to be biased at the second polarity.

22. The system of claim 21 wherein the cortical electrode assembly comprises a plurality of second surface contacts carried by the support member, and the second surface contacts are electrically coupled to the second terminal of the implantable pulse generator to be biased at the second polarity.

23. The system of claim 21 wherein:

the implantable pulse generator further comprises a pulse system and a controller operatively coupled to the pulse system, wherein the controller includes a programmable medium; and

the programmable medium contains instructions that cause the pulse system to concurrently electrically bias the surface contact at the stimulation site at the first polarity while biasing the return contact at the second polarity for a unipolar stimulation period to generate an electrical field extending through deep layers of the cortex in a direction generally normal with respect to the surface contact at the stimulation site.

24. The system of claim 21 wherein:

the implantable pulse generator further comprises a pulse system and a controller operatively coupled to the pulse system, wherein the controller includes a programmable medium; and

the programmable medium contains instructions that cause the pulse system to concurrently electrically bias the surface contact at the stimulation site at the first polarity while biasing the return contact at the second polarity for a unipolar stimulation period to generate an electrical field extending through deep layers of the cortex in a direction running generally in a direction generally perpendicular to a cortical layer structure.

25. A system for applying electrical stimulation to a surface site on a cortex of a patient, comprising:

an implantable pulse generator having a first terminal configured to be biased at a first polarity, a second terminal configured to be biased at a second polarity, and a return contact coupled to the second terminal to be biased at the second polarity; and

a cortical electrode assembly having a support member and a plurality of surface contacts carried by the support member, wherein the surface contacts are coupled to the first terminal of the implantable pulse generator to be biased at the first polarity.

26. The system of claim 25 wherein the cortical electrode assembly comprises a plurality of surface contacts, and the surface contacts are electrically coupled to the first terminal of the implantable pulse generator to be biased at the first polarity.

27. The system of claim 25 wherein:

the implantable pulse generator further comprises a housing, a pulse system in the housing, and a controller in the housing; and

the return contact comprises an electrode fixedly attached to the implantable pulse generator.

28. The system of claim 25 wherein:

the implantable pulse generator further comprises a housing having an electrically conductive section, a pulse system carried by the housing, and a controller carried by the housing, and wherein the electrically conductive section of the housing is electrically coupled to the second terminal; and

the return contact comprises the electrically conductive section of the housing.

29. The system of claim 25 wherein:

the implantable pulse generator further comprises a pulse system and a controller operatively coupled to the pulse system, wherein the controller includes a programmable medium; and

the programmable medium contains instructions that cause the pulse system to concurrently electrically bias the surface contact at the stimulation site at the first polarity while biasing the return contact at the second polarity for a unipolar stimulation period to generate an electrical field extending through deep layers of the cortex in a direction generally normal with respect to the surface contact at the stimulation site.

30. The system of claim 25 wherein:

the implantable pulse generator further comprises a pulse system and a controller operatively coupled to the pulse system, wherein the controller includes a programmable medium; and

the programmable medium contains instructions that cause the pulse system to concurrently electrically bias the surface contact at the stimulation site at the first polarity while biasing the return contact at the second polarity for a unipolar stimulation period to generate an electrical field extending through deep layers of the cortex running generally in a direction generally perpendicular to a cortical layer structure.

31. A system for applying electrical stimulation to a cortex of a patient, comprising:

an implantable housing having a first portion and a second portion;

a pulse generator carried by the implantable housing;

at least one first electrode arrangement carried by the first portion of the housing so as to be positioned at a cortical stimulation site of the patient located at least approximately at or below an inner surface of the patient'"'"'s skull when the housing is implanted; and

at least one second electrode arrangement carried by the second portion of the housing so as to be positioned at least approximately at or above an outer surface of the patient'"'"'s skull and beneath the patient'"'"'s scalp when the housing is implanted.

32. The system of claim 31 wherein the pulse generator includes a first terminal and a second terminal, with at least one of the first and second terminals configured to be biased to a different polarity than the other, and wherein the at least one first electrode arrangement is coupled to the first terminal and the at least one second electrode arrangement is coupled to the second terminal.

33. The system of claim 31 wherein the pulse generator includes a current delivery terminal and a current return terminal, and wherein the at least one first electrode arrangement is coupled to the current delivery terminal and the at least one second electrode arrangement is coupled to the current return terminal.

34. The system of claim 31 wherein the pulse generator includes a first terminal and a second terminal, with at least one of the first and second terminals configured to be biased to a different polarity than the other, and wherein the at least one first electrode arrangement includes two first electrode contacts, and wherein the system further comprises a switching device operatively coupled to the first and second terminals, the switching device having a first configuration with both first electrode contacts electrically coupled to the first terminal and the at least one second electrode arrangement coupled to the second terminal, the switching device further having a second configuration with one first electrode contact electrically coupled to the first terminal and the other first electrode contact coupled to the second terminal.

35. A system for applying electrical stimulation to a patient'"'"'s brain, comprising:

an implantable housing;

a pulse generator carried by the implantable housing, the pulse generator having a first terminal and a second terminal, the pulse generator being configured to deliver to at least one of the first and second terminals a stimulation signal having a plurality of stimulation periods with at least one of the stimulation periods having a duration of about 30 seconds or less;

at least one first electrode carried by the housing and operatively coupled to at least one of the first and second terminals; and

at least one second electrode carried by the housing and operatively coupled to at least one of the first and second terminals.

36. The system of claim 35 wherein the plurality of stimulation periods includes a unipolar stimulation period and a bipolar stimulation period.

37. The system of claim 35 wherein the plurality of stimulation periods includes a first stimulation period at a first polarity and a second stimulation period at a second polarity different than the first.

38. The system of claim 35 wherein the plurality of stimulation periods includes an anodal unipolar stimulation period and a cathodal unipolar stimulation period.

39. The system of claim 35 wherein the plurality of stimulation periods includes different unipolar stimulation periods.

40. The system of claim 35 wherein the pulse generator is configured to deliver the plurality of stimulation periods with a plurality of interruption periods between temporally neighboring stimulation periods, and wherein at least one of the interruption periods, at least one of the stimulation periods, or at least one of both the interruption periods and the stimulation periods has a duration of 30 seconds or less.

41. The system of claim 35 wherein the pulse generator is configured to deliver the stimulation signal with at least one of the stimulation periods having a duration of about 10 seconds or less.

42. The system of claim 35 wherein the pulse generator is configured to deliver the stimulation signal with at least one of the stimulation periods having a duration of about one second or less.

43. The system of claim 35 wherein the pulse generator is configured to deliver the stimulation signal with at least one of the stimulation periods having a duration of less than one second.

44. The system of claim 35 wherein the housing includes a first portion and a second portion, and wherein the at least one first electrode is carried by the first portion of the housing so as to be positioned at a cortical stimulation site of the patient located at least approximately at or below an inner surface of the patient'"'"'s skull when the housing is implanted, and wherein the at least one second electrode is carried by the second portion of the housing so as to be positioned at least approximately at or above an outer surface of the patient'"'"'s skull and beneath the patient'"'"'s scalp when the housing is implanted.

45. A system for applying electrical stimulation to a patient'"'"'s brain, comprising:

an implantable housing;

a pulse generator carried by the implantable housing, the pulse generator having a first terminal and a second terminal and being configured to provide a stimulation signal to at least one of the first and second terminals;

a first electrode arrangement coupled to the first terminal so as to be positioned proximate to a first neural region of the patient'"'"'s brain when the housing is implanted; and

a second electrode arrangement coupled to the second terminal so as to be positioned proximate to a second neural region of the patient'"'"'s brain when the housing is implanted.

46. The system of claim 45, further comprising a return electrode arrangement coupled to the pulse generator so as to be positioned remotely from the first and second electrode arrangements.

47. The system of claim 45 wherein the first electrode assembly is coupled to the first terminal so as to be positioned proximate to a first neural region that carries out a first neural function, and wherein the second electrode assembly is coupled to the second terminal so as to be positioned proximate to a second neural region that carries out a second neural function different than the first.

48. The system of claim 45 wherein the first electrode assembly is coupled to the first terminal so as to be positioned proximate to a first neural region that carries out a first neural function at a first extremity of the patient, and wherein the second electrode assembly is coupled to the second terminal so as to be positioned proximate to a second neural region that carries out a second neural function at a second extremity of the patient.

49. The system of claim 45 wherein the second electrode arrangement is coupled to the second terminal so as to be positioned remotely from the first electrode arrangement when the housing is implanted.

50. A system for applying electrical stimulation to a patient'"'"'s brain, comprising:

an implantable housing;

a pulse generator carried by the implantable housing, the pulse generator having a first terminal and a second terminal and being configured to provide a stimulation signal to at least one of the first and second terminals, the stimulation signal including a plurality of groups of pulses, wherein the pulses within a group are provided at first frequency and the groups are provided at a second frequency less than the first frequency;

a first electrode arrangement coupled to the first terminal so as to be positioned proximate to a neural region of the patient'"'"'s brain when the housing is implanted; and

a second electrode arrangement coupled to the second terminal.

51. The system of claim 50 wherein the pulse generator is configured to provide pulses at a potential corresponding to a subthreshold level.

52. The system of claim 50 wherein the pulse generator is configured to provide first pulses at a potential corresponding to a subthreshold level and second pulses at a potential corresponding to a suprathreshold level.

53. A system for applying electrical stimulation to a patient'"'"'s brain, comprising:

an implantable housing;

a pulse generator carried by the implantable housing, the pulse generator having a first terminal and a second terminal and being configured to provide a stimulation signal to the first and second terminals, the stimulation signal including a first portion wherein an electrical potential is applied to the first terminal at a first polarity and an electrical potential is applied to the second terminal at a second polarity opposite from the first polarity, the stimulation signal further including a second portion wherein an electrical potential is applied to the first terminal at the second polarity and an electrical potential is applied to the second terminal at the first polarity;

a first electrode arrangement coupled to the first terminal so as to be positioned proximate to a neural region of the patient'"'"'s brain when the housing is implanted; and

a second electrode arrangement coupled to the second terminal.

54. The system of claim 53 wherein the pulse generator is configured to provide pulses at a potential corresponding to a subthreshold level.

55. The system of claim 53 wherein the pulse generator is configured to provide first pulses at a potential corresponding to a subthreshold level and second pulses at a potential corresponding to a suprathreshold level.

56. A method of applying electrical stimulation to a cortical stimulation site at a cortex of a patient, comprising:

electrically biasing a plurality of surface contacts at the cortical stimulation site at a single first polarity for a unipolar stimulation period; and

electrically biasing a return site at a second polarity opposite to the first polarity during the unipolar stimulation period, the return site being located apart from the cortical stimulation site along a vector that passes through layers 5 and 6 of the cortex of the patient in a direction that is oblique with respect to a surface contact at the stimulation site.

57. The method of claim 56 wherein:

electrically biasing the stimulation site comprises applying an anodal potential to the surface contacts at the stimulation site; and

electrically biasing the return site comprises applying a cathodal potential to a return contact at the return site to establish an electrical field that passes through layers 5 and 6 of the cortex at the stimulation site in a direction at least substantially normal with respect to the surface contact at the stimulation site.

58. A method of applying electrical stimulation to a cortical stimulation site on a cortex of a patient, comprising:

applying an electrical bias having a single first polarity to a surface contact of a surface electrode assembly positioned at the cortical stimulation site for a unipolar stimulation period; and

applying an electrical bias having a second polarity opposite to the first polarity to a return contact during the unipolar stimulation period to establish an electrical field between the surface contact and the return contact, wherein the return contact is positioned apart from the surface contact assembly so that the electrical field passes through layers 5 and 6 of the cortex in a direction at least substantially normal with respect to a section of the cranium of the patient at the surface stimulation site.

59. The method of claim 58 wherein:

electrically biasing the surface site comprises applying an anodal potential to a plurality of surface contacts at the stimulation site; and

electrically biasing the return site comprises applying a cathodal potential to a return contact at the return site to establish an electrical field that passes through deep layers of the cortex at the stimulation site in a direction at least substantially normal with respect to the section of the cranium of the patient at the stimulation site.

60. A method of applying electrical stimulation to a cortical stimulation site on a cortex of a patient, comprising:

positioning a plurality of surface contacts in a human so that the surface contacts are at least substantially proximate to a surface region of the cortex at the stimulation site;

positioning a return contact at a location spaced apart from the surface contacts; and

applying a unipolar electrical stimulation signal to the surface contacts.

61. The method of claim 60 wherein applying a unipolar electrical signal to the surface contacts comprises electrically biasing the surface contacts with an anodal potential.

62. The method of claim 60 wherein applying a unipolar electrical signal to the surface contacts comprises electrically biasing the surface contacts with a cathodal potential.

63. The method of claim 60 wherein positioning the plurality of surface contacts comprises identifying the stimulation site at an area where neuroplasticity is occurring or expected to occur for recovery of an impaired neural function and placing the plurality of contacts at least approximately within the area.

64. The method of claim 60, further comprising performing a behavioral therapy on the patient.

65. The method of claim 64, wherein the behavioral therapy comprises at least one from the group of a physical therapy, an activity of daily living, an intentional use of an affected body part, a speech therapy, a vision therapy, a reading task, and a memory task.

66. The method of claim 60, further comprising performing a behavioral therapy on the patient concurrently while applying the unipolar electrical stimulation signal to the surface contacts.

67. The method of claim 66, wherein the behavioral therapy comprises at least one from the group of a physical therapy, an activity of daily living, an intentional use of an affected body part, a speech therapy, a vision therapy, an auditory therapy, a reading task, and a memory task.

68. The method of claim 60, wherein the patient has an impaired neural function caused by damage to the brain, and wherein applying the unipolar electrical stimulation signal to the surface contacts comprises electrically biasing the surface contacts with an anodal potential.

69. A method of applying electrical stimulation to a cortical stimulation site on a cortex of a patient, comprising:

positioning a surface electrode assembly so that a surface contact of the surface electrode assembly is at least substantially proximate to a surface region of the cortex at the stimulation site;

positioning a return contact at a location spaced apart from the surface electrode assembly and not in a deep brain region of the brain; and

establishing an electrical field between the surface contact and the return contact that extends through deep layers of the cortex in a direction oblique with respect to the surface contacts.

70. The method of claim 69 wherein establishing the electrical field comprises electrically biasing the surface contact with an anodal potential.

71. The method of claim 69 wherein establishing the electrical field comprises electrically biasing the surface contact with an cathodal potential.

72. The method of claim 69 wherein positioning the surface electrode assembly comprises identifying the stimulation site at an area where neuroplasticity is occurring or expected to occur for recovery of an impaired neural function and placing the surface electrode assembly at least approximately within the area.

73. The method of claim 69, further comprising performing a behavioral therapy on the patient.

74. The method of claim 73, wherein the behavioral therapy comprises at least one from the group of a physical therapy, an activity of daily living, an intentional use of an affected body part, a speech therapy, a vision therapy, a reading task, and a memory task.

75. The method of claim 69, wherein the patient has an impaired neural function caused by damage to the brain, and wherein establishing the electrical field comprises applying a unipolar electrical stimulation signal to the surface contact with an anodal potential.