Cochlear implant and an operating method thereof

Patent metadata

Field	Value
Publication number	US-9844671-B2
Application number	US-201614991319-A
Country	US
Kind code	B2
Filing date	Jan 8, 2016
Priority date	Jan 13, 2015
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

A cochlear implant is disclosed in an embodiment. The implant includes a signal level detector configured to determine a total signal level of an incoming acoustic signal and a processing unit configured to determine, in accordance with the determined total signal level, an intermediate knee point for each of a plurality of frequency bands. The implant includes a bandpass filters configured to generate a plurality of band limited audio signals in dependence upon the incoming acoustic signal, each band limited acoustic signal representing an associated audio frequency range relating to at least one electrode of a plurality of an implanted electrode array of the cochlear implant. The implant includes a pulse controller configured to deliver electrical stimulation signals to the plurality of electrodes of the implanted electrode array based on the generated signals and the determined intermediate knee point corresponding to the frequency range.

First claim

I claim:

1. A cochlear implant comprising
a signal level detector configured to determine a total signal level of an incoming acoustic signal;
a processing unit configured to determine, in accordance with the determined total signal level, an intermediate knee point in a mapping function for one or more frequency bands, wherein the mapping function outputs a charge amount corresponding to a signal level inputted to the mapping function;
a bandpass filters configured to generate a plurality of band limited audio signals in dependence upon the incoming acoustic signal, each band limited audio signal representing an associated audio frequency range relating to at least one electrode of a plurality of an implantable electrode array of the cochlear implant; and
a pulse controller configured to
directly map one or more generated band limited audio signals into a stream of target charge amounts by inputting the signal levels of each of the one or more generated band limited audio signals to the mapping function including the intermediate knee point determined for the corresponding frequency range, and obtaining the corresponding charge amounts outputted by the mapping function as the target charge amounts, and
deliver electrical stimulation signals to the plurality of electrodes of the implantable electrode array by generating electric charge pulses corresponding to the stream of target charge amounts which are outputted by the mapping function in response to the inputted signal levels of the one or more generated band limited audio signals that are directly mapped,
wherein the intermediate knee point defines within the mapping function a loudness growth function comprising a first loudness growth function comprising a first incremental gain below the intermediate knee point and a second loudness growth function comprising a second incremental gain above the intermediate knee point, the first incremental gain being higher than the second incremental gain, and
wherein the mapping function maps the one or more generated band limited audio signals in units of decibels of sound pressure level (dB SPL) into the stream of target charge amounts defined as a percentage of a maximum comfort charge.

2. The cochlear implant according to claim 1 , wherein the signal level detector is configured to
determine the total signal level by estimating signal levels obtained from at least one beamforming mode; or
determine the total signal level by performing weighted combination of the estimated signal levels obtained from different beamforming modes if more than one beamforming mode is used.

3. The cochlear implant according to claim 1 , wherein the processing unit is configured to determine the intermediate knee point by interpolating predefined kneepoint values for the one or more frequency bands.

4. The cochlear implant according to claim 1 , wherein the processing unit is configured to determine the intermediate knee point by accessing a look up table comprising predefined knee point values corresponding to the one or more frequency bands and a plurality of average signal levels.

5. The cochlear implant according to claim 1 , wherein the pulse controller is configured to assign the intermediate kneepoint corresponding to the one or more frequency bands to overlapping audio frequency ranges, thereby defining a knee point for the associated electrode of the plurality of electrodes.

6. The cochlear implant according to claim 1 , wherein the pulse controller is configured to control an incremental gain such that the incremental gain is larger for a level of the incoming signal between a lower threshold level and an intermediate threshold level, defined by the intermediate knee point, than the incremental gain for the level between the intermediate threshold level and an upper threshold level.

7. The cochlear implant according to claim 6 , wherein, in the mapping function, the gain transitions incrementally in the immediate vicinity of the lower threshold level and/or the intermediate threshold level and/or upper threshold level.

8. The cochlear implant according to claim 1 , wherein the processing unit is further configured to analyse the incoming acoustic signal and to adjust the intermediate threshold level in dependence on the analysis such that the intermediate threshold level decreases when the signal processor receives weaker incoming signals and increases when the signal processor receives louder incoming signals.

9. The cochlear implant according to claim 1 , wherein
the first loudness growth function is linear or piecewise linear between a lower kneepoint and the intermediate kneepoint; and/or
the second loudness growth function is linear or piecewise linear between the intermediate kneepoint and an upper kneepoint.

10. The cochlear implant according to claim 1 , wherein the predefined kneepoint values and/or the one or more frequency bands and/or the plurality of average signal levels in the look up table is dependent on a statistical determination and/or an input provided by a user of the cochlear implant.

11. The cochlear implant according to claim 1 , further comprising an input transducer configured to receive the incoming acoustic signal and to provide a corresponding electric input signal; and a digitiser adapted to digitise the electric input signal and to provide the digitised signal as the input audio signal to the signal level detector for determining the total signal level.

12. A method for generating an electrical stimulus of a specified intensity on any audio frequency range relating to at least one electrode of a plurality of an implanted electrode array of a cochlear implant, the method comprising
determining a total signal level of an incoming acoustic signal;
determining, in accordance with the determined total signal level, an intermediate knee point in a mapping function for one or more frequency bands, wherein the mapping function outputs a charge amount corresponding to a signal level inputted to the mapping function;
generating a plurality of band limited audio signals in dependence upon the incoming acoustic signal, each band limited acoustic signal representing an associated audio frequency range relating to at least one of a plurality of electrodes of an implantable electrode array of the cochlear implant;
directly map one or more generated band limited audio signals into a stream of target charge amounts by inputting the signal levels of each of the one or more generated band limited audio signals to the mapping function including the intermediate knee point determined for the corresponding frequency range, and obtaining the corresponding charge amounts outputted by the mapping function as the target charge amounts, and
delivering electrical stimulation signals to the plurality of electrodes of the implantable electrode array by generating electric charge pulses corresponding to the stream of target charge amounts which are outputted by the mapping function in response to the inputted signal levels of the one or more generated band limited audio signals that are directly mapped,
wherein the intermediate knee point defines within the mapping function a loudness growth function comprising a first loudness growth function comprising a first incremental gain below the intermediate knee point and a second loudness growth function comprising a second incremental gain above the intermediate knee point, the first incremental gain being higher than the second incremental gain, and
wherein the mapping function maps the one or more generated band limited audio signals in units of decibels of sound pressure level (dB SPL) into the stream of target charge amounts defined a

Assignees

• Oticon Medical As

Inventors

• Segovia Martinez Manuel

Classifications

• A61N1/0541 Primary

  Cochlear electrodes · CPC title

• A61N1/36038

  Cochlear stimulation · CPC title

• A61F2002/183

  Ear parts · CPC title

• A61N1/02

  Details · CPC title

• H03G9/025

  frequency-dependent volume compression or expansion, e.g. multiple-band systems (H03G9/10, H03G9/18 take precedence) · CPC title