Sound processing and stimulation systems and methods for use with cochlear implant devices
View Patent ↗Sound processing strategies for use with cochlear implant systems utilizing simultaneous stimulation of electrodes are provided. The strategies include computing a frequency spectrum of a signal representative of sound, arranging the spectrum into channels and assigning a subset of electrodes to each channel. Each subset is stimulated so as to stimulate a virtual electrode positioned at a location on the cochlea that corresponds to the frequency at which a spectral peak is located within an assigned channel. The strategies also derive a carrier for a channel having a frequency that may relate to the stimulation frequency so that temporal information is presented. In order to fit these strategies, a group of electrodes is selected and the portion of the current that would otherwise be applied to electrode(s) having a partner electrode in the group is applied to the partner electrode.
1. A sound processing unit for use in a cochlear implant sound processing unit, the unit comprising:
circuitry for computing a frequency spectrum of a signal representative of sound in order to produce a representation of the signal that is broken down into a plurality of frequency bins that are organized into a plurality of channels such that each channel comprises a subset of the plurality of bins; and
additional circuitry being adapted to:
determine a bin that has the most energy out of a subset of the bins corresponding to a channel included within the plurality of channels;
determine whether the energy in the bin is larger than energies in other bins adjacent to the bin;
if the energy in the bin is larger than energies in the adjacent bins, compute a stimulation frequency corresponding to the channel to be a frequency that corresponds to a location of a point in the middle of the bin; and
if the energy in the bin is not larger than energies in the adjacent bins, compute the stimulation frequency corresponding to the channel to be a frequency that corresponds to a location of a point that lies midway between the bin and another bin having the larger energy of the adjacent bins.
2. The sound processing unit of claim 1 , wherein the circuitry for computing the frequency spectrum is configured to apply a Fast Fourier Transform to the signal representative of the sound.
3. The sound processing unit of claim 1 , wherein the additional circuitry is configured to determine the bin that has the most energy by taking a sum of a square of a real part and an imaginary part of the input signal.
4. The sound processing unit of claim 1 , wherein the additional circuitry is configured to determine whether the energy in the bin is larger than the energies in the other bins adjacent to the bin by computing a log of the bin and the other bins.
5. The sound processing unit of claim 1 , wherein the additional circuitry is further configured to translate the stimulation frequency into a cochlear location.
6. The sound processing unit of claim 5 , wherein the translation comprises interpolating the cochlear location from a frequency-to-location table.
7. The sound processing unit of claim 5 , wherein the additional circuitry is configured to cause a cochlear stimulator to stimulate a pair of electrodes using relative current weights to stimulate a virtual electrode at the cochlear location.
8. A sound processing unit for use in a cochlear implant sound processing unit, the unit comprising:
circuitry for computing a frequency spectrum of a signal representative of sound in order to produce a representation of the signal that is broken down into a plurality of frequency bins that are organized into a plurality of channels such that each channel comprises a subset of the plurality of bins; and
additional circuitry being adapted to:
determine a bin that has the most energy out of a subset of the bins corresponding to a channel included within the plurality of channels;
determine whether the energy in the bin is larger than energies in other bins adjacent to the bin; and
if the energy in the bin is not larger than energies in the adjacent bins, compute a stimulation frequency corresponding to the channel to be a frequency that corresponds to a location of a point that lies midway between the bin and another bin having the larger energy of the adjacent bins.
9. The sound processing unit of claim 8 , wherein the circuitry for computing the frequency spectrum is configured to apply a Fast Fourier Transform to the signal representative of the sound.
10. The sound processing unit of claim 8 , wherein if the energy in the bin is not larger than energies in the adjacent bins, the additional circuitry is further configured to compute the stimulation frequency to be a frequency that corresponds to a location of a point in the middle of the bin.
11. The sound processing unit of claim 8 , wherein if the energy in the bin is larger than energies in the adjacent bins, the additional circuitry is further configured to compute the stimulation frequency to be a frequency that corresponds to a location of a maximum of a parabola that is fit between a plurality of points within the bin and two of the adjacent bins.
12. The sound processing unit of claim 8 , wherein the additional circuitry is configured to determine whether the energy in the bin is larger than the energies in the other bins adjacent to the bin by computing a log of the bin and the other bins.
13. The sound processing unit of claim 8 , wherein the additional circuitry is further configured to translate the stimulation frequency into a cochlear location.
14. The sound processing unit of claim 13 , wherein the translation comprises interpolating the cochlear location from a frequency-to-location table.
15. The sound processing unit of claim 13 , wherein the additional circuitry is configured to cause a cochlear stimulator to stimulate a pair of electrodes using relative current weights to stimulate a virtual electrode at the cochlear location.
16. A sound processing unit for use in a cochlear implant sound processing unit, the unit comprising:
circuitry for computing a frequency spectrum of a signal representative of sound in order to produce a representation of the signal that is broken down into a plurality of frequency bins that are organized into a plurality of channels such that each channel comprises a subset of the plurality of bins; and
additional circuitry being adapted to:
determine a bin that has the most energy out of a subset of the bins corresponding to a channel included within the plurality of channels;
determine whether the energy in the bin is larger than energies in other bins adjacent to the bin;
if the energy in the bin is larger than energies in the adjacent bins, compute a stimulation frequency to be a frequency that corresponds to a location of a maximum of a parabola that is fit between a plurality of points within the bin and two of the adjacent bins; and
if the energy in the bin is not larger than energies in the adjacent bins, compute the stimulation frequency to be a frequency that corresponds to a location of a point that lies midway between the bin and another bin having the larger energy of the adjacent bins.
17. The sound processing unit of claim 16 , wherein the circuitry for computing the frequency spectrum is configured to apply a Fast Fourier Transform to the signal representative of the sound.
18. The sound processing unit of claim 16 , wherein the additional circuitry is further configured to translate the stimulation frequency into a cochlear location.
19. The sound processing unit of claim 18 , wherein the additional circuitry is configured to cause a cochlear stimulator to stimulate a pair of electrodes using relative current weights to stimulate a virtual electrode at the cochlear location.