Outer Hair Cell Stimulation Model for the Use by an Intra-Cochlear Implant

• US 20100179616A1
• Filed: 03/22/2010
• Published: 07/15/2010
• Est. Priority Date: 12/03/2004
• Status: Active Grant

• Current Assignee: Advanced Bionics AG (Sonova Holding AG)
• Original Assignee: Advanced Bionics LLC (Sonova Holding AG)
• Inventors: Litvak, Leonid M., Fridman, Gene Y.
• Granted Patent: US 8,121,698 B2
• Time in Patent Office: Days
• US Class Current: 607/57
• CPC Class Codes: A61N 1/36038 Cochlear stimulation
• CPC Class Codes: G10L 2021/065 Aids for the handicapped in understanding
• CPC Class Codes: G10L 21/02 Speech enhancement, e.g. noise reduction or echo cancellation reducing echo effects in line transmission systems H04B3/20; echo suppression in hands-free telephones H04M9/08
• CPC Class Codes: H04S 3/002 Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution control circuits for electronic adaptation of the sound field H04S7/30

Abstract

Contrast between various frequency components of sound is enhanced through a lateral suppression strategy to provide increased speech perception in the electrically stimulated cochlea. A received audio signal is divided into a plurality of input signals, wherein each input signal is associated with a frequency band. A plurality of envelope signals are generated by determining the envelope of each of a plurality of the input signals. At least one of the envelope signals is scaled in accordance with a scaling factor to generate at least one scaled envelope signal. An output signal is generated by combining at least one envelope signal with at least one scaled envelope signal, and the cochlea is stimulated based on the generated output signal. The lateral suppression strategy can be applied to one or more frequency bands using scaled amplitude signals associated with one or more neighboring frequency bands.

Claims

1. A method of generating a cochlear stimulation signal for use in a cochlear implant, the method comprising:

filtering an audio signal into at least a first input signal and a second input signal, wherein the first and second input signals respectively comprise a first band of frequencies and a second band of frequencies from the audio signal;

determining a first envelope signal indicative of the magnitude of the first input signal and a second envelope signal indicative of the magnitude of the second input signal; and

producing a cochlear stimulation signal for a cochlear implant electrode using the first envelope signal and the second envelope signal.

2. The method of claim 1, wherein the first and second bands of frequencies are adjacent.

3. The method of claim 1, wherein producing the cochlear stimulation signal comprises weighting either or both of the first and second envelope signals.

4. The method of claim 3, wherein producing the cochlear stimulation signal further comprises summing the weighted first or second envelope signals.

5. The method of claim 1, wherein the first band of frequencies and the second band of frequencies are mapped to electrodes on the cochlear implant by a sound processing strategy.

6. The method of claim 5, wherein the sound processing strategy comprises one of a simultaneous analog stimulation strategy, a continuous interleaved sampler strategy, and a frequency modulated stimulation strategy.

7. A method of generating cochlear stimulation signals for use in a cochlear implant, the method comprising:

filtering an audio signal into a plurality of input signals, wherein each input signal comprises a band of frequencies from the audio signal;

determining an envelope signal for each of the input signals, wherein each envelope signal is indicative of the magnitude of its corresponding input signal;

determining a suppression signal for each of the envelope signals, wherein each suppression signal is determined as a function of its corresponding envelope signal and at least one other non-corresponding envelope signal; and

producing a plurality of cochlear stimulation signals each corresponding to a particular electrode of the cochlear implant, wherein each cochlear stimulation signal is produced from one of the plurality of suppression signals.

8. The method of claim 7, wherein each suppression signal comprises a weighted sum of its corresponding envelope signal and at least one other non-corresponding envelope signal.

9. The method of claim 7, wherein each suppression signal comprises a weighted sum of its corresponding envelope signal and an adjacent other non-corresponding envelope signal.

10. The method of claim 7, wherein a corresponding envelope signal comprises E_i, at least one other non-corresponding envelope signal comprises E_j, and wherein the determined suppression signal S_i comprises:

$S_i=u_i<br><br>E_i+F_i\left(\underset{j}{\sum <br><br>}<br><br><br><br>w_{\mathrm{ij}}<br><br>E_j\right)$

wherein u_i comprises a weighting factor and w_ij comprises a scaling factor.

11. The method of claim 7, wherein each of the bands of frequencies are mapped to electrodes on the cochlear implant by a sound processing strategy.

12. The method of claim 11, wherein the sound processing strategy comprises one of a simultaneous analog stimulation strategy, a continuous interleaved sampler strategy, and a frequency modulated stimulation strategy.

13. A method of generating cochlear stimulation signals for use in a cochlear implant, the method comprising:

filtering an audio signal into a plurality of input signals, wherein each input signal comprises a band of frequencies from the audio signal;

determining an envelope signal for each of the input signals, wherein each envelope signal is indicative of the magnitude of its corresponding input signal, wherein a first contrast exists between adjacent envelope signals;

modifying each envelope signal to form a corresponding suppression signal, wherein the suppression signals comprise a second contrast between adjacent suppression signals different from the first contrast; and

producing a plurality of cochlear stimulation signals each corresponding to a particular electrode of the cochlear implant, wherein each cochlear stimulation signal is produced from one of the plurality of suppression signals.

14. The method of claim 13, wherein at least one of the envelope signals represents a spectral peak, and wherein modifying each envelope signal to form a corresponding suppression signal comprise decreasing at least one suppression signals adjacent to the peak.

15. The method of claim 13, wherein the second contrast is larger than the first contrast.

16. The method of claim 13, wherein modifying each envelope signal E_i to form a corresponding suppression signal S₁ comprises use of the formula:

$S_i=u_i<br><br>E_i+F_i\left(\underset{j}{\sum <br><br>}<br><br><br><br>w_{\mathrm{ij}}<br><br>E_j\right)$

wherein u_i comprises a weighting factor and w_ij comprises a scaling factor.

17. The method of claim 13, wherein each of the bands of frequencies are mapped to electrodes on the cochlear implant by a sound processing strategy.

18. The method of claim 17, wherein the sound processing strategy comprises one of a simultaneous analog stimulation strategy, a continuous interleaved sampler strategy, and a frequency modulated stimulation strategy.