Methods and systems for representing different spectral components of an audio signal presented to a cochlear implant patient
An exemplary method of representing different spectral components of an audio signal presented to a cochlear implant patient includes identifying one or more spectral peaks of an audio signal presented to a cochlear implant patient, applying electrical stimulation representative of the one or more spectral peaks to at least one stimulation site within the cochlear implant patient using a partial multipolar stimulation configuration, and applying electrical stimulation representative of one or more other spectral components of the audio signal to at least one other stimulation site within the cochlear implant patient using a monopolar stimulation configuration. Corresponding methods and systems are also disclosed.
1. A method comprising:
dividing an audio signal presented to a cochlear implant patient into a plurality of analysis channels each containing a frequency domain signal representative of a distinct frequency portion of the audio signal;
detecting a maximum energy level of each of the frequency domain signals;
identifying, based on the detected maximum energy levels of each of the frequency domain signals, one or more spectral peaks and one or more other spectral components of the audio signal;
selectively applying electrical stimulation representative of the one or more spectral peaks to at least one stimulation site within the cochlear implant patient using a partial multipolar stimulation configuration; and
selectively applying electrical stimulation representative of the one or more other spectral components of the audio signal to at least one other stimulation site within the cochlear implant patient using a monopolar stimulation configuration;
wherein the selectively applying of the electrical stimulation representative of the one or more spectral peaks using the partial multipolar stimulation configuration comprises concurrently
applying a main current to a main electrode, and
applying compensating current to one or more compensating electrodes,
wherein the compensating current is opposite in polarity compared to the main current and less than the main current, and
wherein a remaining amount of current equal to a difference between the main current and the compensating current flows to an extracochlear ground electrode.
2. The method of claim 1 , wherein the identifying of the one or more spectral peaks comprises:
designating a predetermined number of the detected maximum energy levels as corresponding to one of the one or more spectral peaks based on the detected maximum energy levels.
3. The method of claim 1 , wherein the identifying of the one or more spectral peaks comprises:
designating the detected maximum energy levels that are greater than a predetermined threshold value as corresponding to the one or more spectral peaks.
4. The method of claim 1 , further comprising:
generating one or more stimulation parameters based on the identified spectral peaks and the one or more other spectral components of the audio signal; and
generating the electrical stimulation representative of the one or more spectral peaks and the electrical stimulation representative of the one or more other spectral components of the audio signal in accordance with the one or more stimulation parameters.
5. The method of claim 1 , wherein the one or more spectral peaks comprise one or more formants within the audio signal.
6. The method of claim 1 , wherein the one or more other spectral components of the audio signal comprise at least one spectral valley.
7. The method of claim 1 , wherein the audio signal comprises speech.
8. The method of claim 1 , wherein the partial multipolar stimulation configuration comprises one of a partial bipolar stimulation configuration and a partial tripolar stimulation configuration.
9. The method of claim 1 , wherein the one or more compensating electrodes comprises two compensating electrodes adjacent to the main electrode.