MULTI-ELECTRODE CHANNEL CONFIGURATIONS

• US 20110288613A1
• Filed: 05/18/2010
• Published: 11/24/2011
• Est. Priority Date: 05/18/2010
• Status: Active Grant

• Current Assignee: Cochlear Limited
• Original Assignee: Cochlear Limited
• Inventors: van den Honert, Christopher, Smith, Zachary M.
• Granted Patent: US 9,031,661 B2
• Time in Patent Office: Days
• US Class Current: 607/57
• CPC Class Codes: A61N 1/0541 Cochlear electrodes
• CPC Class Codes: A61N 1/36038 Cochlear stimulation
• CPC Class Codes: A61N 1/36039 fitting procedures
• CPC Class Codes: A61N 1/37264 Changing the program; Upgrading firmware
• CPC Class Codes: G10L 2021/065 Aids for the handicapped in understanding
• CPC Class Codes: H03G 9/005 of digital or coded signals
• CPC Class Codes: H04R 25/70 Adaptation of deaf aid to hearing loss, e.g. initial electronic fitting

Abstract

An apparatus and method for determining stimulation channels for a stimulating device is provided. This method and apparatus may involve computing a set of weights for the plurality of stimulation channels of the stimulating hearing prosthesis. These weights may be determined by determining a transimpedance matrix for the stimulating hearing prosthesis where a diagonal of the transimpedance matrix is determined by extrapolation. A transadmittance matrix may then be computed for this transimpedance matrix. An error may then be computed base on positive off-diagonal terms of the transadmittance matrix. The apparatus and method may determine the weights for the stimulation channels by determining an adjustment to the diagonal of the transimpedance matrix that results in a computed error that does not exceed a specified criterion level.

Claims

1. A method for determining weights for a stimulation channel of a stimulating hearing prosthesis having a plurality of electrodes, wherein the stimulation channel uses the determined weights in providing stimulation using a plurality of the electrodes of the stimulating medical device, the method comprising:

determining a transimpedance matrix for the plurality of electrodes;

computing a transadmittance matrix for the plurality of electrodes, the transadmittance matrix being a matrix inversion of the transimpedance matrix;

computing an error based on positive off-diagonal values of the transadmittance matrix;

determining if the error exceeds a criterion level;

adjusting a diagonal of the transimpedance matrix if the criterion level is exceeded;

calculating the corresponding weights for the plurality of electrodes for the stimulation channel using the adjusted transimpedance matrix; and

providing the calculated weights to the stimulating medical device for use in providing stimulation to a recipient of the stimulating medical device.

2. The method of claim 1, wherein the steps of computing a transadmittance matrix, computing an error, determining if the error exceeds a criterion level, and adjusting the diagonal are repeated until the step of determining if the error exceeds the criterion level determines that the error does not exceed the criterion level.

3. The method of claim 1, further comprising:

computing a complex channel matrix by normalizing at least one column of the computed transadmittance matrix; and

wherein computing an error comprises computing the error based on positive off-diagonal values of the complex channel matrix.

4. The method of claim 1, further comprising:

executing a minimization algorithm to determine a set of one or more gain values for adjusting the diagonal of the transimpedance matrix that results in a determined error that does not exceed the criterion level.

5. The method of claim 4, wherein the minimization algorithm includes the steps of computing a transadmittance matrix, computing an error, determining if the error exceeds a criterion level, and adjusting the diagonal.

6. The method of claim 4, further comprising:

determining a cost based on the set of one or more gain values; and

wherein the minimization algorithm identifies a set of one or more gain values, with the determined cost, that provides an error that does not exceed the criterion level.

8. The method of claim 4, wherein the minimization algorithm uses a sequential quadratic programming method to obtain the set of one or more gain values by determining the set of one or more gain values that provides the minimum error for the determined cost.

9. The method of claim 4, wherein the minimization algorithm terminates upon identifying a set of one or more gain values, for the determined cost, that provides an error that does not exceed the criterion level.

10. The method of claim 1, wherein the stimulating medical device is a cochlear implant.

20. The apparatus of claim 1, wherein the stimulating hearing prosthesis is a cochlear implant.

7. The method of claim 7, wherein determining a cost comprises:

adjusting the determined cost to determine a minimal cost in which the minimization algorithm identifies a set of one or more gain values, with the determined cost, that provides an error that does not exceed the criterion level.

11. An apparatus for determining weights for a stimulation channel of a stimulating hearing prosthesis having a plurality of electrodes, wherein the stimulation channel uses the determined weights in providing stimulation using a plurality of the electrodes of the stimulating hearing prosthesis, the apparatus comprising:

error minimization module configured to compute a transadmittance matrix by inverting a determined transimpedance matrix, compute an error based on positive off-diagonal values of the transadmittance matrix, determine if the error exceeds a criterion level; and

adjust a diagonal of the transimpedance matrix if the criterion level is exceeded; and

a weight calculation module configured to calculate corresponding weights for the plurality of electrodes for the stimulation channel; and

an interface configured to provide the calculated weights to the stimulating hearing prosthesis for use in providing stimulation to a recipient of the stimulating hearing prosthesis.

12. The apparatus of claim 11, wherein the error minimization module is configured to repeat, until the minimization module determines an error that does not exceed the criterion level, the steps of computing a transadmittance matrix, computing an error, determining if the error exceeds a criterion level, and adjusting the diagonal.

13. The apparatus of claim 11, wherein the error minimization module is further configured to compute a complex channel matrix by normalizing at least one column of the computed transadmittance matrix, and wherein, in computing an error, the error minimization module is configured to compute the error based on positive off-diagonal values of the complex channel matrix.

14. The apparatus of claim 11, the error minimization module is configured to execute a minimization algorithm to determine a set of one or more gain values for adjusting the diagonal of the transimpedance matrix that results in a determined error that does not exceed the criterion level.

15. The apparatus of claim 14, wherein the minimization algorithm includes the steps of computing a transadmittance matrix, computing an error, determining if the error exceeds a criterion level, and adjusting the diagonal.

16. The apparatus of claim 14 further comprising:

a cost minimization module configured to determine a cost based on the set of one or more gain values; and

wherein the minimization algorithm is configured to identify a set of one or more gain values, with the determined cost, that provides an error that does not exceed the criterion level.

17. The apparatus of claim 16, wherein the cost minimization module in determining a cost is configured to adjust the determined cost to determine a minimal cost in which the minimization algorithm identifies a set of one or more gain values, with the determined cost, that provides an error that does not exceed the criterion level.

18. The apparatus of claim 14, wherein the minimization algorithm uses a sequential quadratic programming method to obtain the set of one or more gain values by determining the set of one or more gain values that provides the minimum error for the determined cost.

19. The apparatus of claim 14, wherein the minimization algorithm is configured to terminate upon identifying a set of one or more gain values, for the determined cost, that provides an error that does not exceed the criterion level.

21. A computer program embodied on a computer readable medium, the computer program comprising program code for controlling a processor to execute a method for determining weights for a stimulation channel of a stimulating hearing prosthesis having a plurality of electrodes, wherein the stimulation channel uses the determined weights in providing stimulation using a plurality of the electrodes of the stimulating hearing prosthesis, the method comprising:

determining a transimpedance matrix for the plurality of electrodes;

computing a transadmittance matrix for the plurality of electrodes, the transadmittance matrix being a matrix inversion of the transimpedance matrix;

computing an error based on positive off-diagonal values of the transadmittance matrix;

determining if the error exceeds a criterion level;

adjusting a diagonal of the transimpedance matrix if the criterion level is exceeded;

calculating the corresponding weights for the plurality of electrodes for the stimulation channel using the adjusted transimpedance matrix; and

providing the calculated weights to the stimulating hearing prosthesis for use in providing stimulation to a recipient of the stimulating hearing prosthesis.

22. An apparatus for determining weights for a stimulation channel of a stimulating device having a plurality of electrodes, wherein the stimulation channel uses the determined weights in providing stimulation using a plurality of the electrodes of the stimulating hearing prosthesis, the apparatus comprising:

means for determining a transimpedance matrix for the plurality of electrodes;

means for computing a transadmittance matrix by inverting the transimpedance matrix;

means for computing a transadmittance matrix for the plurality of electrodes, the transadmittance matrix being a matrix inversion of the transimpedance matrix;

means for determining if the error exceeds a criterion level;

means for adjusting a diagonal of the transimpedance matrix if the criterion level is exceeded;

means for calculating the corresponding weights for the plurality of electrodes for the stimulation channel using the adjusted transimpedance matrix; and

means for providing the calculated weights to the stimulating hearing prosthesis for use in providing stimulation to a recipient of the stimulating hearing prosthesis.