METHOD AND APPARATUS FOR CONTROLLING ELECTRICAL STIMULATION

• US 20090248110A1
• Filed: 01/23/2009
• Published: 10/01/2009
• Est. Priority Date: 03/28/2008
• Status: Active Grant

• Current Assignee: National Chiao Tung University (Government of The Republic of China)
• Original Assignee: National Chiao Tung University (Government of The Republic of China)
• Inventors: CHOI, Charles Tak Ming, Hsu, Chien Hua
• Granted Patent: US 8,340,758 B2
• Time in Patent Office: Days
• US Class Current: 607/45
• CPC Class Codes: A61N 1/0541 Cochlear electrodes
• CPC Class Codes: A61N 1/36038 Cochlear stimulation

Abstract

An apparatus and method for controlling an electrical stimulation system to increase the resolution of the stimulation region with multiple independent power source electrodes is proposed. In the apparatus, the electrode set contains at least three electrodes of which two adjacent electrodes are of the same power polarity to control the location of the composite stimulation signal and the others are of an inverse power polarity to balance the total power polarity and narrow the stimulation region. The method for the apparatus comprises steps of: receiving a target stimulation location and level, generating at least one parameter to adjust power settings of the electrodes, thereby obtaining a composite stimulation signal corresponding to a virtual channel of which a location and level match the target stimulation location and level.

Claims

1. An apparatus for controlling electrical stimulation used for stimulating nerve fibers, comprising:

an electrode array including a plurality of electrodes each of which is separately powered and controlled by an independent power source; and

an electrode controller for receiving input control signals and driving an electrode set in the electrode array so as to generate a composite stimulation signal in the electrode set;

wherein the electrode set comprises a plurality of electrodes, of which two adjacent electrodes are of a first power polarity for controlling a location of the composite stimulation signal, and one or more other electrodes are of a second power polarity which is inverse with respect to the first power polarity, so as to balance a total power polarity of the electrode set and focus on a stimulation region of the composite stimulation signal which is generated between the two adjacent electrodes.

2. The apparatus according to claim 1, wherein the electrodes of the first power polarity have a polarity sum designated as P, and the electrodes of the second power polarity have a polarity sum designated as −

P, where P is a total power setting.

3. The apparatus according to claim 1, wherein the electrodes of the first power polarity have a polarity sum designated as −

P, and the electrodes of second power polarity have a polarity sum designated as P, where P is a total power setting.

4. The apparatus according to claim 2, wherein the two adjacent electrodes of the first power polarity have a power setting designated as (−

(1−

α

))P and (−

α

)P, respectively, while the electrode of the second power polarity has a power setting designated as P, where α

is a parameter ranging from 0 to 1, the location of the composite stimulation signal can be controlled by adjusting the parameter α

.

5. The apparatus according to claim 3, wherein the two adjacent electrodes of the first power polarity have a power setting designated as (1−

α

)P and (α

)P, respectively, while the electrode of the second power polarity has a power setting designated as −

P, where α

is a parameter ranging from 0 to 1, the location of the composite stimulation signal can be controlled by adjusting the parameter α

.

6. The apparatus according to claim 2, wherein the two adjacent electrodes of the first power polarity have a power setting designated as (1−

A)P and (A)P, respectively, while the electrodes of the second power polarity have a power setting designated as (−

B)P and (−

(1−

B))P, respectively, where A and B are parameters ranging from 0 to 1, the location of the composite stimulation signal can be controlled by adjusting the parameters A and B.

7. The apparatus according to claim 3, wherein the electrodes of the first power polarity have a power setting designated as (−

(1−

A))P and (−

A)P, respectively, while the electrodes of the second power polarity have a power setting designated as (B)P and (1−

B)P, respectively, where A and B are parameters ranging from 0 to 1, the location of the composite stimulation signal can be controlled by adjusting the parameters A and B.

8. The apparatus according to claim 1, wherein the electrodes of the first power polarity are disposed at one side of the electrode set, and the electrodes of the second power polarity are disposed at the other side of the electrode set, so as to generate the composite stimulation signal on the side of the electrode set where the electrodes of the first power polarity are disposed.

9. The apparatus according to claim 7, wherein the electrodes of the first power polarity are disposed at a central part of the electrode set, and the electrodes of the second power polarity are disposed at a part of the electrode set other than the central part, so as to generate a composite stimulation signal on the central part of the electrode set.

10. The apparatus according to claim 7, wherein the parameters A and B are designated so that they are equal to each other.

11. The apparatus according to claim 7, wherein the parameters A and B are designated so that an equation, A+B=1, is fulfilled.

12. The apparatus according to claim 7, wherein the parameter A is designated as 0.5 and the parameter B is designated as α

, where α

is a parameter ranging from 0 to 1.

13. The apparatus according to claim 7, wherein the parameter A is designated as α

and the parameter B is designated as 0.5, where α

is a parameter ranging from 0 to 1.

14. The apparatus according to claim 7, wherein the parameter A is designated as a known corresponding parameter in a table Ti and the parameter B is designated as α

, which ranges from 0 to 1, where the table Ti is a table established according to characteristics of users that correspond to the i^th virtual channel, and the table Ti is established in advance according to parameters for adjusting a current ratio of the two adjacent electrodes, or according to a length ratio of the i^th virtual channel to the two adjacent electrodes.

15. The apparatus according to claim 1, which is applied to a cochlear implant, a retinal prosthesis, a spinal cord stimulation apparatus, or a deep brain stimulation apparatus.

16. The apparatus according to claim 2, wherein the total power setting P is applied by an independent voltage source (V) or an independent current source (I).

17. A method for controlling electrical stimulation with a plurality of electrodes for stimulating nerve fibers, the method comprising:

receiving a target stimulation location and level; and

generating at least one parameter for adjusting power settings of an electrode set to be driven in an electrode array, so as to obtain a composite stimulation signal corresponding to a virtual channel of which a location and level match the target stimulation location and level;

wherein the electrode set includes a plurality of electrodes, in which two adjacent electrodes are of a first power polarity for controlling the location of the composite stimulation signal, while one or more other electrodes are of a second power polarity which is inverse with respect to the first power polarity, so as to balance the total power polarity of the electrode set and focus on a stimulation region of the composite stimulation signal.

18. The method according to claim 17, wherein the two adjacent electrodes of the first power polarity have a polarity sum designated as P, and the electrodes of the second power polarity have a polarity sum designated as −

P, where P is a total power setting.

19. The method according to claim 17, wherein the two adjacent electrodes of the first power polarity have a polarity sum designated as −

P, and the electrodes of second power polarity have a polarity sum designated as P, where P is a total power setting.

20. The method according to claim 18, wherein the two adjacent electrodes of the first power polarity have a power setting designated as (1−

α

)P and (α

)P, respectively, while the electrode of the second power polarity has a power setting designated as −

P, where α

is a parameter ranging from 0 to 1, the location of the composite stimulation signal can be controlled by adjusting the parameter α

.

21. The method according to claim 19, wherein the two adjacent electrodes of the first power polarity have a power setting designated as (−

(1−

α

))P and (−

α

)P, respectively, while the electrode of the second power polarity has a power setting designated as P, where α

is a parameter ranging from 0 to 1, the location of the composite stimulation signal can be controlled by adjusting the parameter α

.

22. The method according to claim 18, wherein the two adjacent electrodes of the first power polarity have a power setting designated as (1−

A)P and (A)P, respectively, while the electrodes of the second power polarity have a power setting designated as (−

B)P and (−

(1−

B))P, respectively, where A and B are parameters ranging from 0 to 1, the location of the composite stimulation signal can be controlled by adjusting the parameters A and B.

23. The method according to claim 19, wherein the two adjacent electrodes of the first power polarity have a power setting designated as (−

(1−

A))P and (−

A)P, respectively, while the electrodes of the second power polarity have a power setting designated as (B)P and (1−

B)P, respectively, where A and B are parameters ranging from 0 to 1, the location of the composite stimulation signal can be controlled by adjusting the parameters A and B.

24. The method according to claim 17, wherein the two adjacent electrodes of the first power polarity are disposed at one side of the electrode set, and the electrodes of the second power polarity are disposed at the other side of the electrode set, so as to generate the composite stimulation signal on the side of the electrode set where the two adjacent electrodes of the first power polarity are disposed.

25. The method according to claim 23, wherein the two adjacent electrodes of the first power polarity are disposed at a central part of the electrode set, and the electrodes of the second power polarity are disposed at a part of the electrode set other than the central part, so as to generate the composite stimulation signal on the central part of the electrode set.

26. The method according to claim 23, wherein the parameters A and B are designated so that they are equal to each other.

27. The method according to claim 23, wherein the parameters A and B are designated so that an equation, A+B=1, is fulfilled.

28. The method according to claim 23, wherein the parameter A is designated as 0.5 and the parameter B is designated as α

, where α

is a parameter ranging from 0 to 1.

29. The method according to claim 23, wherein the parameter A is designated as α

and the parameter B is designated as 0.5, where α

is a parameter ranging from 0 to 1.

30. The method according to claim 23, wherein the parameter A is designated as a known corresponding parameter in a table Ti and the parameter B is designated as α

ranging from 0 to 1, where the table Ti is a table established according to characteristics of users that correspond to the i^th virtual channel, and the table Ti is established in advance according to parameters for adjusting a current ratio of the two adjacent electrodes, or according to a length ratio of the i^th virtual channel to the two adjacent electrodes.

31. The method according to claim 17, which is applied to a cochlear implant, a retinal prosthesis, a spinal cord stimulation apparatus, or a deep brain stimulation apparatus.

32. An apparatus for controlling electrical stimulation used for stimulating nerve fibers, comprising:

an electrode array including a plurality of electrodes, each of which is separately powered and controlled by an independent power source; and

an electrode controller for receiving input control signals and driving an electrode set in the electrode array so as to generate an composite stimulation signal in the electrode set;

wherein the electrode set comprises a plurality of electrodes, of which at least one electrode is of a first power polarity and other electrodes are of a second power polarity which is inverse with respect to the first power polarity, so as to balance a total power polarity of the electrode set and focus on a stimulation region of the composite stimulation signal.

33. The apparatus according to claim 32, wherein power settings of four electrodes are (1−

α

)AP, (2α

−

1−

α

B)P, (1−

2α

+α

A−

A)P and (α

B)P, respectively, where P is a total power setting, and α

, A and B are parameters ranging from 0 to 1.

34. The apparatus according to claim 33, wherein the parameters A and B are designated so that they are equal to each other.

35. The apparatus according to claim 33, wherein the parameters A and B are designated as 0.5.

36. The apparatus according to claim 32, which is applied a cochlear implant, a retinal prosthesis, a spinal cord stimulation apparatus, or a deep brain stimulation apparatus.

37. A method for controlling electrical stimulation with a plurality of electrodes for stimulating nerve fibers, the method comprising:

receiving a target stimulation location and level; and

generating at least one parameter for adjusting power setting of a electrode set to be driven in an electrode array, so as to obtain a composite stimulation signal corresponding to a virtual channel of which a location and level match the target stimulation location and level;

wherein the electrode set includes a plurality of electrodes, in which at least one electrode is of a first power polarity and other electrodes are of a second power polarity which is inverse with respect to the first power polarity, so as to balance a total power polarity of the electrode set and concentrate stimulation region of the composite stimulation signal.

38. The method according to claim 37, wherein the power settings of four electrodes are (1−

α

)AP, (2α

−

1−

α

B)P, (1−

2α

+α

A−

A)P and (α

B)P, respectively, where P is a total power setting, and α

, A and B are parameters ranging from 0 to 1.

39. The method according to claim 38, wherein the parameters A and B are designated so that they are equal to each other.

40. The method according to claim 38, wherein the parameters A and B are designated as 0.5.

41. The method according to claim 37, which is applied to a cochlear implant, retinal prosthesis, a spinal cord stimulation apparatus, or a deep brain stimulation apparatus.