COCHLEAR IMPLANT USING OPTICAL STIMULATION WITH ENCODED INFORMATION DESIGNED TO LIMIT HEATING EFFECTS

• US 20130023963A1
• Filed: 07/21/2012
• Published: 01/24/2013
• Est. Priority Date: 07/22/2011
• Status: Active Grant

• Current Assignee: Nurotone Medical Ltd.
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Stafford, Ryan C., Stafford, James W.
• Granted Patent: US 8,840,654 B2
• Time in Patent Office: Days
• US Class Current: 607/88
• CPC Class Codes: A61N 1/0541 Cochlear electrodes
• CPC Class Codes: A61N 1/36039 fitting procedures
• CPC Class Codes: A61N 2005/0605 Ear
• CPC Class Codes: A61N 2005/0626 Monitoring, verifying, controlling systems and methods
• CPC Class Codes: A61N 2005/0652 Arrays of diodes
• CPC Class Codes: A61N 2005/0659 infrared
• CPC Class Codes: A61N 5/0622 Optical stimulation for exciting neural tissue
• CPC Class Codes: A61N 5/067 using laser light
• CPC Class Codes: F04C 2270/0421 Controlled or regulated

Abstract

Method and apparatus for optically stimulating neurons of a plurality of auditory nerve pathways of a person to provide auditory sensations for the person by generating a plurality of pulsed light signals having one or more successive pulses. The spectrum of a detected audio signal is divided into M channels. In some embodiments, an N-of-M coding strategy is employed, where, for any given time frame, only N of the M channels are selected and illuminated to stimulate the auditory nerves. In some embodiments, the M channels are organized into bins, where, for any given time frame, only a maximum number of channels are illuminated per bin. This limits the number of illuminated channels-per-length of cochlea and therefore prevents localized heating of the cochlea and reduces power consumption of the device.

Claims

1. A method comprising:

obtaining an audio signal having an audio spectrum;

for each of a plurality of successive time frames including a first, second, third and fourth time frame, generating a plurality of “

M”

audio channels of the audio spectrum, each of the plurality of “

M”

audio channels for one of the plurality of time frames having a sub-portion of frequencies of the audio spectrum for a period of time corresponding to that one of the plurality of frames; and

for each of the plurality of time frames;

selecting a subset of “

N”

audio channels selected from the “

M”

audio channels by an “

N of M”

coding strategy;

for each one of the subset of “

N”

audio channels, generating a corresponding pulsed light signal having one or more successive pulses that, when applied to a neuron of a person, will each stimulate a nerve action potential (NAP) in the neuron; and

delivering the generated corresponding pulsed light signals to a corresponding one of a plurality of frequency-specific locations in the cochlea of the person to optically stimulate one or more neurons in the cochlea in order to trigger NAPs in the one or more neurons of the cochlea.

2. The method of claim 1, wherein the plurality of “

M”

audio channels are organized into a plurality of bins, each of the plurality of bins having a plurality of audio channels, and wherein, for each bin, the selected subset of “

N”

audio channels includes a maximum of fewer than all audio channels within that one bin.

3. The method of claim 2, wherein adjacent ones of the audio channels of the plurality of audio channels in each bin are directed towards neurons that, when triggered, are perceived by the person to be adjacent to each other in frequency.

4. The method of claim 3, wherein selecting the subset of “

N”

audio channels includes selecting an individual one of the “

M”

audio channels at no more than two successive time frames during the plurality of successive time frames.

5. The method of claim 1, wherein the selected subset of “

N”

audio channels during the first time frame includes eleven audio channels corresponding to eleven portions of the audio spectrum having a strongest signal selected from the “

M”

audio channels during the first time frame, and wherein the first time frame is in a range between approximately 4 milliseconds and approximately 7.5 milliseconds.

6. The method of claim 1, wherein the selecting of the subset of “

N”

audio channels includes limiting selection of an individual one of the “

M”

audio channels to be in no more than two successive time frames during the plurality of successive time frames.

7. An apparatus for optically stimulating neurons of a cochlea of a person, the apparatus comprising:

means for obtaining an audio signal having an audio spectrum;

means for generating a plurality of “

M”

audio channels of the audio spectrum for each of a plurality of successive time frames including a first, second, third and fourth time frame, each of the plurality of “

M”

audio channels for one of the plurality of time frames having a sub-portion of frequencies of the audio spectrum for a period of time corresponding to that one of the plurality of frames;

means for selecting for each of the plurality of time frames a subset of “

N”

audio channels selected from the “

M”

audio channels by an “

N of M”

coding strategy;

means for generating for each of the plurality of time frames a corresponding pulsed light signal having one or more successive pulses for each one of the subset of “

N”

audio channels that, when applied to a neuron of a person, will each stimulate a nerve action potential (NAP) in the neuron; and

means for delivering for each of the plurality of time frames the generated corresponding pulsed light signals to a corresponding one of a plurality of frequency-specific locations in the cochlea of the person to optically stimulate one or more neurons in the cochlea in order to trigger NAPs in the one or more neurons of the cochlea.

8. The apparatus of claim 7, wherein the plurality of “

M”

audio channels are organized into a plurality of bins, each of the plurality of bins having a plurality of audio channels, and wherein, for each bin, the selected subset of “

N”

audio channels includes a maximum of fewer than all audio channels within that one bin.

9. The apparatus of claim 7, wherein the plurality of “

M”

audio channels are organized into a plurality of bins, each of the plurality of bins having a plurality of the plurality of audio channels, and wherein, for each bin, the selected subset of “

N”

audio channels includes a maximum of fewer than all audio channels within that one bin, and wherein the means for selecting the subset of “

N”

audio channels includes means for selecting a minimum of at least “

X”

audio channels from each of the plurality of bins, and means for selecting a maximum of no more than “

Y”

audio channels from each of the plurality of bins.

10. The apparatus of claim 7, wherein a subset of the plurality of audio channels in each bin is also in an adjacent bin, wherein a first frequency range covered by the adjacent audio channels in a first bin partially overlaps with a second frequency range covered by the adjacent audio channels in a second bin.

11. The apparatus of claim 7, wherein the means for selecting the subset of “

N”

audio channels includes selecting an individual one of the “

M”

audio channels at no more than two successive time frames during the plurality of successive time frames.

12. The apparatus of claim 7, wherein the means for selecting is further configured to select the subset of “

N”

audio channels, such that an individual one of the “

M”

audio channels is selected at no more than two successive time frames during the plurality of successive time frames.

13. The apparatus of claim 7, wherein the means for selecting is further configured to select the subset of “

N”

audio channels during the first time frame such that eleven audio channels corresponding to eleven portions of the audio spectrum having a strongest signal are selected from the “

M”

audio channels during the first time frame, and wherein the first time frame is in a range of approximately 4 milliseconds to 7.5 milliseconds.

14. An apparatus for optically stimulating neurons of a cochlea of a person, the apparatus comprising:

an audio sensor configured to obtain an audio signal having an audio spectrum;

an audio processor configured to generate a plurality of “

M”

audio channels of the audio spectrum for each of a plurality of successive time frames including a first, second, third and fourth time frame, each of the plurality of “

M”

audio channels for one of the plurality of time frames having a sub-portion of frequencies of the audio spectrum for a period of time corresponding to that one of the plurality of frames;

a channel mapper configured to select for each of the plurality of time frames a subset of “

N”

audio channels selected from the “

M”

audio channels by an “

N of M”

coding strategy;

an optical generator configured to output, for each of the plurality of time frames, a corresponding pulsed light signal having one or more successive pulses for each one of the subset of “

N”

audio channels that, when applied to a neuron of a person, will each stimulate a nerve action potential (NAP) in the neuron; and

an optical guide configured to deliver, for each of the plurality of time frames, the generated corresponding pulsed light signals to a corresponding one of a plurality of frequency-specific locations in the cochlea of the person to optically stimulate one or more neurons in the cochlea in order to trigger NAPS in the one or more neurons of the cochlea.

15. The apparatus of claim 14, wherein the plurality of “

M”

audio channels are organized into a plurality of bins, each of the plurality of bins having a plurality of audio channels, and wherein, for each bin, the selected subset of “

N”

audio channels includes a maximum of fewer than all audio channels within that one bin.

16. The apparatus of claim 14, wherein the plurality of “

M”

audio channels are organized into a plurality of bins, each of the plurality of bins having a plurality of audio channels, and wherein, for each bin, the selected subset of “

N”

audio channels includes a maximum of fewer than all audio channels within that one bin, and wherein the channel mapper is further configured to select the subset of “

N”

audio channels, wherein the subset of “

N”

audio channels are chosen such that a minimum of at least “

X”

audio channels is selected from each of the plurality of bins, and a maximum of no more than “

Y”

audio channels are selected from each of the plurality of bins.

17. The apparatus of claim 14, wherein adjacent ones of the audio channels of the plurality of audio channels in each bin are directed towards neurons that, when triggered, are perceived by the person to be adjacent to each other in frequency.

18. The apparatus of claim 17, wherein a subset of the plurality of audio channels in each bin is also in an adjacent bin, wherein a first frequency range covered by the adjacent audio channels in a first bin partially overlaps with a second frequency range covered by the adjacent audio channels in a second bin.

19. The apparatus of claim 14, wherein the channel mapper is further configured to select the subset of “

N”

audio channels, wherein the subset of “

N”

audio channels is selected such that an individual one of the “

M”

audio channels is selected at no more than two successive time frames during the plurality of successive time frames.

20. The apparatus of claim 14, wherein the selected subset of “

N”

audio channels during the first time frame includes eleven audio channels corresponding to eleven portions of the audio spectrum having a strongest signal selected from the “

M”

audio channels during the first time frame, and wherein the first time frame is in a range of approximately 4 milliseconds to 7.5 milliseconds.