Enhanced methods for determining iso-loudness contours for fitting cochlear implant sound processors

• US 7,043,303 B1
• Filed: 08/25/2003
• Issued: 05/09/2006
• Est. Priority Date: 08/30/2002
• Status: Expired due to Fees

• Current Assignee: Advanced Bionics LLC (Sonova Holding AG)
• Original Assignee: Advanced Bionics Corporation (Sonova Holding AG)
• Inventors: Overstreet, Edward H.
• Primary Examiner(s): Jastrzab, Jeffrey R.
• Assistant Examiner(s): ALTER, ALYSSA MARGO
• Application Number:
  US10/647,372
• Time in Patent Office: 988 Days
• Field of Search: 607/55, 607/56, 607/57, 607/136, 607/137, 607/66
• US Class Current: 607/57
• CPC Class Codes: A61N 1/36038 Cochlear stimulation
• CPC Class Codes: A61N 1/36039 fitting procedures

Abstract

Methods are taught to simplify the cochlear implant fitting process for various cochlear prostheses and stimulation strategies, including high rate stimulation strategies. For instance, patient self-programming is made possible. In addition, auto-fitting is made possible (particularly useful for very young patients and other patients for whom it is challenging to obtain feedback) using iso-neural response contours which can be linearly transposed to arrive at iso-loudness contours. Furthermore, M iso-loudness contours (or iso-neural contours) can be linearly transposed to determine T iso-loudness contours. In addition, wider pulse widths can be used to generate an iso-loudness contour whose shape can be used (via linear transposition) to program high-rate, narrow pulse width stimulation.

Claims

1. A method of fitting a cochlear implant, the cochlear implant having an electrode array with multiple electrode contacts through which a pulsatile stimulation waveform having a pulse rate and a pulse width may be applied to the cochlea of the patient;

and wherein the fitting method builds an M iso-loudness contour and determines a T iso-loudness contour, the method comprising;

a) setting a starting sound level to build an iso-loudness contour;

b) setting volume on a first channel until the sound is at a predetermined level;

c) adjusting volume on a second channel until the volume of sound on the second channel is similar to the volume of sound on the first channel;

then

d) setting the next channel to result in the same sound volume determined for the previous channel;

e) repeating step (d) for each available channel until the stimulation level for the last channel is adjusted, and the M iso-loudness contour is built; and

f) picking one channel and determining the volume level of that one channel; and

g) generating a T-iso-loudness contour by determining the difference in the volume level measured for the one channel in step f) and the M volume level found previously for that channel and linearly shifting the M iso-loudness contour by the determined difference in volume level.

2. The method of claim 1 wherein the starting sound level is no sound.

3. The method of claim 1 wherein the sound includes a tone or tones.

4. The method of claim 1 wherein the sound includes noise.

5. The method of claim 1 wherein the sound includes speech.

6. The method of claim 1 wherein the predetermined level is a comfortable level.

7. The method of claim 1 wherein the predetermined level is a threshold level.

8. The method of claim 1 wherein at least one channel is a virtual channel.

9. The method of claim 1 wherein at least one channel is skipped.

10. A method of fitting a cochlear implant, the cochlear implant having an electrode array with multiple electrode contacts through which a pulsatile stimulation waveform having a pulse rate and a pulse width may be applied to the cochlea of the patient;

and wherein the fitting method sets an iso-loudness contour from an iso-neural response contour, the method comprising;

determining an iso-neural response contour; and

linearly transposing the iso-neural contour to set an iso-loudness contour.

11. The method of claim 10 further comprising using at least one of neural response imaging and evoked auditory brainstem response to determine the iso-neural response contour.

12. The method of claim 10 further comprising

determining an M level for at least one channel;

determining a difference between the iso-neural level and the M level for the at least one channel; and

linearly transposing the iso-neural contour by the amount of the difference to set the iso-loudness contour.

13. The method of claim 10 wherein the iso-loudness contour is an M iso-loudness contour.

14. The method of claim 10 wherein the iso-loudness contour is a T iso-loudness contour.

15. A method of fitting a cochlear implant, the cochlear implant having an electrode array with multiple electrode contacts through which a pulsatile stimulation waveform having a pulse rate and a pulse width may be applied to the cochlea of the patient;

and wherein the fitting method uses at least two iso-loudness contours, the method comprising;

determining a first iso-loudness response contour; and

linearly transposing the first iso-loudness contour to set a second iso-loudness contour.

16. The method of claim 15 wherein the first iso-loudness contour is an M iso-loudness contour.

17. The method of claim 16 wherein the second iso-loudness contour is a T iso-loudness contour.

18. The method of claim 15 further comprising:

determining a difference between the first iso-loudness contour level and the second iso-loudness contour using at least one channel; and

linearly transposing the first iso-loudness contour by the amount of the difference to set the second iso-loudness contour.

19. A method of fitting a cochlear implant, the cochlear implant having an electrode array with multiple electrode contacts through which a pulsatile stimulation waveform having a pulse rate and a pulse width may be applied to the cochlea of the patient;

and wherein the fitting method determines an iso-loudness contour, the method comprising;

setting pulse width to about 30 μ

s to about 75 μ

s;

determining an iso-loudness contour with the set pulse width; and

linearly transposing the iso-loudness contour for use with pulse widths of about 10 μ

s to about 20 μ

s.

20. The method of claim 19 further comprising:

determining a difference between the iso-loudness contour level with the set pulse width and a comfortable volume for pulse widths of about 10 μ

s to about 20 μ

s; and

linearly transposing the iso-loudness contour by the amount of the difference.