OPTIMIZING PITCH AND OTHER SPEECH STIMULI ALLOCATION IN A COCHLEAR IMPLANT

• US 20080021551A1
• Filed: 07/31/2007
• Published: 01/24/2008
• Est. Priority Date: 12/11/2002
• Status: Active Grant

• Current Assignee: Advanced Bionics AG (Sonova Holding AG)
• Original Assignee: Advanced Bionics Corporation (Sonova Holding AG)
• Inventors: Overstreet, Edward, Harrison, William, Litvak, Leonid
• Granted Patent: US 7,805,198 B2
• Time in Patent Office: Days
• US Class Current: 623/10
• CPC Class Codes: A61N 1/36038 Cochlear stimulation

Abstract

Errors in pitch (frequency) allocation within a cochlear implant are corrected in order to provide a significant and profound improvement in the quality of sound perceived by the cochlear implant user. In one embodiment, the user is stimulated with a reference signal, e.g., the tone “A” (440 Hz) and then the user is stimulated with a probe signal, separated from the reference signal by an octave, e.g., high “A” (880 Hz). The user adjusts the location where the probe signal is applied, using current steering, until the pitch of the probe signal, as perceived by the user, matches the pitch of the reference signal, as perceived by the user. In this manner, the user maps frequencies to stimulation locations in order to tune his or her implant system to his or her unique cochlea.

Claims

1. A cochlear implant system comprising

an implantable pulse generator;

an electrode array having a multiplicity of electrodes connected to the implantable pulse generator;

means for generating a reference signal;

means for applying the reference signal to an appropriate electrode on the electrode array;

means for generating a probe signal having a fixed interval relationship with the reference signal;

means for applying the probe signal to an appropriate electrode on the electrode array;

means for determining when the probe signal matches the reference signal;

means for shifting the location where the probe signal or reference signal is applied until the two signals match; and

means for generating a frequency map that uses the location at which the probe signal is applied and the location at which the reference signal is applied when the two signals match; and

means for using the frequency map to apply stimulus signals to correct locations within a cochlea as a function of pitch;

wherein the means for shifting the location where the probe signal or reference signal is applied comprises current steering means for steering the location where a stimulus is applied to any location along the electrode array; and

wherein the means for generating a probe signal comprises means for generating a probe signal that has a known tonal relationship with the reference signal.

2. The system of claim 1 wherein current steering means comprises using current steering to shift the location of the probe signal while maintaining the location of the reference signal constant.

3. The system of claim 1 wherein current steering means comprises using current steering to shift the location of the reference signal while maintaining the location of the probe signal constant.

4. The system of claim 1 further including means for generating additional reference signals and probe signals and means for determining the respective locations at which the probe signal and reference signals match to augment the frequency map.

5. The system of claim 1 further including means for adjusting the stimulation parameters of the reference and probe signals in order to obtain a best possible match between the two signals, wherein the stimulation parameters include pulse amplitude and pulse width.

6. A cochlear implant system comprising

an implantable pulse generator;

an electrode array having a multiplicity of electrodes connected to the implantable pulse generator;

means for generating a reference signal;

means for applying the reference signal to an appropriate electrode on the electrode array;

means for generating a probe signal having a fixed interval relationship with the reference signal;

means for applying the probe signal to an appropriate electrode on the electrode array;

means for determining when the probe signal matches the reference signal;

means for shifting the location where the probe signal or reference signal is applied until the two signals match; and

means for generating a frequency map that uses the location at which the probe signal is applied and the location at which the reference signal is applied when the two signals match; and

means for using the frequency map to apply stimulus signals to correct locations within a cochlea as a function of pitch;

wherein the means for shifting the location where the probe signal or reference signal is applied comprises current steering means for steering the location where a stimulus is applied to any location along the electrode array; and

wherein the means for generating a probe signal comprises means for generating a probe signal that has a known speech sound relationship with the reference signal.

7. The system of claim 6 wherein current steering means comprises using current steering to shift the location of the probe signal while maintaining the location of the reference signal constant.

8. The system of claim 6 wherein current steering means comprises using current steering to shift the location of the reference signal while maintaining the location of the probe signal constant.

9. The system of claim 6 further including means for generating additional reference signals and probe signals and means for determining the respective locations at which the probe signal and reference signals match to augment the frequency map.

10. The system of claim 6 further including means for adjusting the stimulation parameters of the reference and probe signals in order to obtain a best possible match between the two signals, wherein the stimulation parameters include pulse amplitude and pulse width.

11. In a neurostimulation system, a method for correcting frequency allocation comprising

controlling the location where a stimulus is applied using current steering;

controlling the temporal waveform structure of the stimulus that is applied; and

applying a reference stimulus and a probe stimulus, and wherein a fixed interval relationship exists between the reference signal and the probe signal; and

wherein the desired criteria comprises achieving a match between the reference signal and the probe signal,

wherein the fixed interval relationship between the reference signal and the probe signal comprises an octave relationship wherein the probe signal is one octave above or below the reference signal.

12. The method of claim 11 wherein using current steering comprises using current steering to shift the location of the probe signal while maintaining the location of the reference signal constant.

13. The method of claim 11 wherein using current steering comprises using current steering to shift the location of the reference signal while maintaining the location of the probe signal constant.

14. The method of claim 11 further including generating additional reference signals and probe signals and determining the respective locations at which the probe signal and reference signals match.

15. The method of claim 11 further including adjusting the stimulation parameters of the reference and probe signals in order to obtain a best possible match between the two signals, wherein the stimulation parameters include pulse amplitude and pulse width.