FOCUSING SYSTEMS AND METHODS FOR USE IN A COCHLEAR IMPLANT SYSTEM
An exemplary sound processor (104) may 1) identify a stimulation site within a cochlea of a patient that is to be stimulated in order to represent an audio signal presented to the patient, 2) dynamically designate, based on the identified stimulation site, a first group of one or more electrodes as a group of one or more main electrodes and a second group of one or more electrodes as a group of one or more compensating electrodes and 3) dynamically determine, based on the identified stimulation site, an amount of main current to be applied to each electrode included in the first group of one or more electrodes in order to represent the audio signal and an amount of compensating current to be applied to each electrode included in the second group of one or more electrodes to focus an excitation field created by the main current.
The present application claims priority to U.S. Provisional Patent Application No. 61/737,676, filed Dec. 14, 2012, the contents of which are hereby incorporated by reference in their entirety.
BACKGROUND INFORMATIONCurrent steering is often used in cochlear implant systems to more effectively represent sound presented to cochlear implant patients. In traditional current steering strategies, weighted stimulation current is applied concurrently to two adjacent electrodes by a cochlear implant system in order to stimulate a stimulation site located in between areas associated with the electrodes. In this manner, the cochlear implant system may create a perception of a frequency in between the frequencies associated with the electrodes.
While current steering is effective in augmenting sound perception, it may introduce spectral broadening, which in turn may compromise spectral resolution. This may be particularly problematic in cases where an audio signal (e.g., speech) includes spectral peaks that represent the distinguishing or meaningful frequency components of the audio signal. In these cases, it may be desirable to present electrical stimulation representative of the spectral peaks to a cochlear implant patient in as fine of spectral resolution as possible.
The accompanying drawings illustrate various embodiments and are a part of the specification. The illustrated embodiments are merely examples and do not limit the scope of the disclosure. Throughout the drawings, identical or similar reference numbers designate identical or similar elements.
Focusing systems and methods for use in a cochlear implant system are described herein. As will be described below, a sound processor included in a cochlear implant system may 1) identify a stimulation site within a cochlea of a patient that is to be stimulated in order to represent an audio signal presented to the patient, the stimulation site included within a plurality of stimulation sites associated with a stimulation channel corresponding to a plurality of electrodes, 2) dynamically designate, based on the identified stimulation site, a first group of one or more electrodes included in the plurality of electrodes as a group of one or more main electrodes and a second group of one or more electrodes included in the plurality of electrodes as a group of one or more compensating electrodes, and 3) dynamically determine, based on the identified stimulation site, an amount of main current to be applied to each electrode included in the first group of one or more electrodes in order to represent the audio signal and an amount of compensating current to be applied to each electrode included in the second group of one or more electrodes to focus an excitation field created by the main current. The sound processor may then direct a cochlear implant associated with the patient to stimulate the identified stimulation site by applying the determined amount of main current to the first group of one or more electrodes and applying the determined amount of compensation current to the second group of one or more electrodes.
As used herein, a stimulation strategy that includes “focusing” refers to a stimulation strategy that directs a cochlear implant to apply compensating current to one or more compensating electrodes while main current representative of a portion of an audio signal is applied to one or more main electrodes. As will be described below, the compensating current is opposite in phase compared to the main current and serves to focus (e.g., narrow) the excitation field produced by the main current, thereby resulting in finer spectral resolution compared to stimulation strategies in which focusing is not used. Focusing may also be referred to as “spectral focusing.”
By using the identified stimulation site to both dynamically designate different electrodes associated with the same stimulation channel as either main electrodes or compensating electrodes and to dynamically determine different amounts of main current and compensating current to be applied to the electrodes, the systems and methods described herein may enhance frequency resolution, reduce spectral smearing, and improve patient perception of audio signals. Another benefit of the systems and methods described herein is that they may be used to maintain a constant excitation field width for a particular stimulation channel, which may improve patient perception of audio signals and minimize fluctuations in noise perception by a patient. Maintaining a constant excitation field width is described more fully in co-pending PCT Application No. ______, attorney docket number 3021-0398-WO, entitled “Systems and Methods for Controlling a Width of an Excitation Field Created by Current Applied by a Cochlear Implant System,” filed the same day as the present application and incorporated herein by reference in its entirety.
Microphone 102 may be configured to detect audio signals presented to the patient. Microphone 102 may be implemented in any suitable manner. For example, microphone 102 may include a microphone that is configured to be placed within the concha of the ear near the entrance to the ear canal, such as a T-MIC™ microphone from Advanced Bionics. Such a microphone may be held within the concha of the ear near the entrance of the ear canal by a boom or stalk that is attached to an ear hook configured to be selectively attached to sound processor 104. Additionally or alternatively, microphone 102 may be implemented by one or more microphones disposed within headpiece 106, one or more microphones disposed within sound processor 104, one or more beam-forming microphones, and/or any other suitable microphone as may serve a particular implementation.
Sound processor 104 (i.e., one or more components included within sound processor 104) may be configured to direct cochlear implant 108 to generate and apply electrical stimulation (also referred to herein as “stimulation current”) representative of one or more audio signals (e.g., one or more audio signals detected by microphone 102, input by way of an auxiliary audio input port, etc.) to one or more stimulation sites associated with an auditory pathway (e.g., the auditory nerve) of the patient. Exemplary stimulation sites include, but are not limited to, one or more locations within the cochlea, the cochlear nucleus, the inferior colliculus, and/or any other nuclei in the auditory pathway. To this end, sound processor 104 may process the one or more audio signals in accordance with a selected sound processing strategy or program to generate appropriate stimulation parameters for controlling cochlear implant 108. Sound processor 104 may include or be implemented by a behind-the-ear (“BTE”) unit, a body worn device, and/or any other sound processing unit as may serve a particular implementation. For example, sound processor 104 may be implemented by an electro-acoustic stimulation (“EAS”) sound processor included in an EAS system configured to provide electrical and acoustic stimulation to a patient.
In some examples, sound processor 104 may wirelessly transmit stimulation parameters (e.g., in the form of data words included in a forward telemetry sequence) and/or power signals to cochlear implant 108 by way of a wireless communication link 114 between headpiece 106 and cochlear implant 108. It will be understood that communication link 114 may include a bi-directional communication link and/or one or more dedicated uni-directional communication links.
Headpiece 106 may be communicatively coupled to sound processor 104 and may include an external antenna (e.g., a coil and/or one or more wireless communication components) configured to facilitate selective wireless coupling of sound processor 104 to cochlear implant 108. Headpiece 106 may additionally or alternatively be used to selectively and wirelessly couple any other external device to cochlear implant 108. To this end, headpiece 106 may be configured to be affixed to the patient's head and positioned such that the external antenna housed within headpiece 106 is communicatively coupled to a corresponding implantable antenna (which may also be implemented by a coil and/or one or more wireless communication components) included within or otherwise associated with cochlear implant 108. In this manner, stimulation parameters and/or power signals may be wirelessly transmitted between sound processor 104 and cochlear implant 108 via a communication link 114 (which may include a bi-directional communication link and/or one or more dedicated uni-directional communication links as may serve a particular implementation).
Cochlear implant 108 may include any type of implantable stimulator that may be used in association with the systems and methods described herein. For example, cochlear implant 108 may be implemented by an implantable cochlear stimulator. In some alternative implementations, cochlear implant 108 may include a brainstem implant and/or any other type of active implant or auditory prosthesis that may be implanted within a patient and configured to apply stimulation to one or more stimulation sites located along an auditory pathway of a patient.
In some examples, cochlear implant 108 may be configured to generate electrical stimulation representative of an audio signal processed by sound processor 104 (e.g., an audio signal detected by microphone 102) in accordance with one or more stimulation parameters transmitted thereto by sound processor 104. Cochlear implant 108 may be further configured to apply the electrical stimulation to one or more stimulation sites within the patient via one or more electrodes 112 disposed along lead 110 (e.g., by way of one or more stimulation channels formed by electrodes 112). In some examples, cochlear implant 108 may include a plurality of independent current sources each associated with a channel defined by one or more of electrodes 112. In this manner, different stimulation current levels may be applied to multiple stimulation sites simultaneously (also referred to as “concurrently”) by way of multiple electrodes 112.
As shown in
Processing facility 302 may be configured to process an audio signal presented to a cochlear implant patient (e.g., an audio signal detected by microphone 102, an audio signal input by way of an auxiliary audio input port, etc.). For example, processing facility 302 may perform one or more pre-processing operations, spectral analysis operations, noise reduction operations, mapping operations, and/or any other types of signal processing operations on a detected audio signal as may serve a particular application.
In some examples, processing facility 302 may divide an audio signal presented to a cochlear implant patient into a plurality of analysis channels each containing a frequency domain signal (or simply “signal”) representative of a distinct frequency portion of the audio signal. This may be performed in any suitable manner. For example, processing facility 302 may be implemented by a plurality of band-pass filters configured to divide the audio signal into a plurality of frequency channels or bands. Additionally or alternatively, processing facility 302 may be configured to convert the audio signal from a time domain into a frequency domain and then divide the resulting frequency bins into the plurality of analysis channels. To this end, processing facility 302 may include one or more components configured to apply a Discrete Fourier Transform (e.g., a Fast Fourier Transform (“FFT”)) to the audio signal.
To illustrate,
Each analysis channel 404 may contain a frequency domain signal representative of a distinct frequency portion of audio signal 402. For example, the portion of audio signal 402 that is included in the frequency band defined by frequencies f0 and f1 may be referred to as the frequency domain signal contained within analysis channel 404-1.
As illustrated in
Each analysis channel 404 may correspond to a stimulation channel 408 (e.g., stimulation channels 408-1 through 408-7). Each stimulation channel 408 may be defined by one or more electrodes (e.g., one or more of electrodes E1 through E8). In the particular example of
Each electrode may be located at a position within the cochlea (or any other structure within the patient) that corresponds to a stimulation site associated with a particular frequency. For example, electrode E1 is located at a position that corresponds to a stimulation site associated with frequency f0. Hence, stimulation of electrode E1 by itself may result in the patient perceiving frequency f0. As will be described below, to represent an audio signal having a frequency that corresponds to a stimulation site located in between stimulation sites associated with two electrodes, current steering between the two electrodes may be used. It will be recognized, however, that the correspondence between the electrode location and the associated spectral region may not be exact, but could depend on, among other factors, electrode placement and unique anatomical features of an individual patient.
As mentioned, each stimulation channel 408 may be defined by one or more electrodes. However, any number of electrodes may correspond to the stimulation channel 408. For example, electrodes E2 and E3 define stimulation channel 408-2 shown in
To illustrate,
For example,
However, in accordance with a stimulation strategy that includes focusing, compensating current 512-1 and 512-2 (collectively “compensating current 512”) opposite in polarity compared to that of main current 508-1 and 508-2 (collectively “main current 508”) may be applied to electrodes Ek−2 and Ek+1 concurrently with the application of main current 508-1 and 508-2 to electrodes Ek−1 and Ek. As shown, electrodes Ek−2 and Ek+1 surround electrodes Ek−1 and Ek. Compensating current 512 serves to focus the excitation field associated with the peak envelope, as represented by envelope 514. It will be recognized that compensating current may be applied by way of any number of compensating electrodes.
As will be described below, the systems and methods described herein facilitate dynamic selection of which electrodes are to be designated as main electrodes and which electrodes are to be designated as compensating electrodes. The systems and methods described herein also facilitate dynamic determination of an amount of main current to be applied to each of the designated main electrodes and amount of compensating current to be applied to each of the compensating electrodes. For example, with respect to the example provided in
To this end, processing facility 302 may identify a stimulation site within a cochlea of a patient that is to be stimulated in order to represent an audio signal presented to the patient. The stimulation site may be included within a plurality of stimulation sites associated with a stimulation channel corresponding to a plurality of electrodes. For example, referring to
Processing facility 302 may identify a stimulation site within a cochlea of a patient that is to be stimulated in order to represent an audio signal presented to the patient in any suitable manner. For example, processing facility 302 may determine a frequency of a spectral peak associated with the audio signal and included in an analysis channel that corresponds to the frequency channel. Processing facility 302 may then identify a stimulation site that corresponds to the identified frequency. For example, in order to represent the frequency domain signal included in analysis channel 404-1, processing facility 302 may determine a frequency of spectral peak 406-1 and identify a stimulation site that corresponds to the frequency of spectral peak 406-1. Alternatively, a stimulation site may be determined after psychophysical masking principles are applied to determine the shape of the spectrum as it would be presented in the auditory system of a normally-hearing individual.
Stimulation management facility 304 may be configured to manage (e.g., control) stimulation provided by cochlear implant 108. For example, as mentioned, processing facility 302 may identify a stimulation site that is to be stimulated in order to represent an audio signal presented to the patient and that is associated with a stimulation channel that corresponds to a plurality of electrodes. In response, stimulation management facility 304 may dynamically designate, based on the identified stimulation site, a first group of one or more electrodes included in the plurality of electrodes as a group of one or more main electrodes and a second group of one or more electrodes included in the plurality of electrodes as a group of one or more compensating electrodes. In some examples, the first and second groups of one or more electrodes do not overlap (i.e., they each include a distinct set of electrodes). Stimulation management facility 304 may also dynamically determine, based on the identified stimulation site, an amount of main current to be applied to each electrode included in the first group of one or more electrodes in order to represent the audio signal and an amount of compensating current to be applied to each electrode included in the second group of one or more electrodes to focus an excitation field created by the main current. Stimulation management facility 304 may then direct cochlear implant 108 to stimulate the identified stimulation site by concurrently applying the determined amount of main current to the first group of one or more electrodes and the determined amount of compensation current to the second group of one or more electrodes. Various examples of this will now be provided.
In some examples, four electrodes correspond to the stimulation channel associated with the identified stimulation site—a first electrode, a second electrode, a third electrode, and a fourth electrode sequentially disposed within the cochlea. The first electrode is the most apically disposed of the four electrodes and the fourth electrode is the most basally disposed of the four electrodes. In these examples, stimulation management facility 304 may perform the dynamic designation and the dynamic determination in accordance with a quadripolar with correction stimulation strategy. As used herein, a “quadripolar with correction stimulation strategy” is one in which stimulation management facility 304 dynamically designates, based on the identified stimulation site, one or both of the middle electrodes (i.e., the second and/or third electrodes) as main electrodes and the remaining electrodes as compensating electrodes.
To illustrate an exemplary quadripolar with correction stimulation strategy, reference is made to
Panel 602-1 shows an exemplary excitation field 604-1 (represented by a dotted line) that may result in response to monopolar stimulation of electrode E2 in isolation. Such monopolar stimulation is illustrated in
Panel 602-1 also shows an exemplary excitation field 604-2 (represented by a dashed line) that may result in response to monopolar stimulation of electrode E3 in isolation. Such monopolar stimulation is illustrated in
Panel 602-1 also shows an exemplary excitation field 604-3 (represented by a solid line) that may result in response to concurrent monopolar stimulation of electrodes E2 and E3. Such monopolar stimulation is illustrated in
As mentioned, panel 602-2 shows excitation fields that may occur in response to stimulation of various electrode configurations in accordance with a quadripolar stimulation strategy. As used herein, a quadripolar stimulation strategy is one in which fixed (i.e., fixed amplitude) compensating current is applied to two electrodes surrounding two electrodes that define a stimulation channel. In the example of
To illustrate, panel 602-2 shows an exemplary excitation field 608-1 (represented by a dotted line) that may result in response to stimulation of electrode E2 in the presence of fixed compensating current applied to electrodes E1 and E4. Such stimulation is illustrated in
Panel 602-2 also shows an exemplary excitation field 608-2 (represented by a dashed line) that may result in response to stimulation of electrode E3 in the presence of fixed compensating current applied to electrodes E1 and E4. Such stimulation is illustrated in
Panel 602-2 also shows an exemplary excitation field 608-3 (represented by a solid line) that may result in response to concurrent stimulation of electrodes E2 and E3 in the presence of fixed compensating current applied to electrodes E1 and E4. Such stimulation is illustrated in
Now that monopolar and quadripolar stimulation strategies have been described, the benefits of a quadripolar with correction stimulation strategy may be recognized. To illustrate, panel 602-3 shows an exemplary excitation field 612-1 (represented by a dotted line) that may result in response to stimulation of electrode E2 in the presence of dynamically determined compensating current applied to electrodes E1, E3, and E4. Such stimulation is illustrated in
As illustrated in
Panel 602-3 also shows an exemplary excitation field 612-2 (represented by a dashed line) that may result in response to stimulation of electrode E3 in the presence of dynamically determined compensating current applied to electrodes E1, E2, and E4. Such stimulation is illustrated in
As illustrated in
Panel 602-3 also shows an exemplary excitation field 612-3 (represented by a solid line) that may result in response to concurrent stimulation of electrodes E2 and E3 in the presence of dynamically determined compensating current applied to electrodes E1 and E4. Such stimulation is illustrated in
In general, stimulation management facility 304 may use the quadripolar with correction stimulation strategy illustrated in
For example, processing facility 302 may identify a stimulation site associated with electrode E2 as the stimulation site that is to be stimulated in order to represent an audio signal to a patient. In response, stimulation management facility 304 may dynamically designate, based on the identified stimulation site, electrode E2 as being a lone main electrode and electrodes E1, E3, and E4 as being compensating electrodes. Stimulation management facility 304 may also dynamically determine, based on the identified stimulation site, an amount of main current to be applied to electrode E2, a first weighted amount of compensating current to be applied to electrode E1, a second weighted amount of compensating current to be applied to electrode E3, and a third weighted amount of compensating current to be applied to electrode E4. Stimulation management facility 304 may then direct cochlear implant 108 to stimulate the identified stimulation site by concurrently applying the determined amount of main current to electrode E2 and the determined weighted amounts of compensating current to electrodes E1, E3, and E4.
Processing facility 302 may subsequently identify a stimulation site associated with electrode E3 as the stimulation site that is to be stimulated in order to represent a different audio signal to the patient. In response, stimulation management facility 304 may dynamically designate, based on the identified stimulation site, electrode E3 as being a lone main electrode and electrodes E1, E2, and E4 as being compensating electrodes. Stimulation management facility 304 may also dynamically determine, based on the identified stimulation site, an amount of main current to be applied to electrode E3, a first weighted amount of compensating current to be applied to electrode E1, a second weighted amount of compensating current to be applied to electrode E2, and a third weighted amount of compensating current to be applied to electrode E4. Stimulation management facility 304 may then direct cochlear implant 108 to stimulate the identified stimulation site by concurrently applying the determined amount of main current to electrode E3 and the determined weighted amounts of compensating current to electrodes E1, E2, and E4.
Processing facility 302 may subsequently identify a stimulation site located somewhere in between stimulation sites associated with electrodes E2 and E3 as the stimulation site that is to be stimulated in order to represent yet a different audio signal to the patient. In response, stimulation management facility 304 may dynamically designate, based on the identified stimulation site, electrodes E2 and E3 as being main electrodes and electrodes E1 and E4 as being compensating electrodes. Stimulation management facility 304 may also dynamically determine, based on the identified stimulation site, a first weighted amount of main current to be applied to electrode E2, a second weighted amount of main current to be applied to electrode E3, a first weighted amount of compensating current to be applied to electrode E1, and a second weighted amount of compensating current to be applied to electrode E4. Stimulation management facility 304 may then direct cochlear implant 108 to stimulate the identified stimulation site by concurrently applying the determined weighted amounts of main current to electrodes E2 and E3 and the determined weighted amounts of compensating current to electrodes E1 and E4.
Continuing with the example in which four electrodes correspond to the stimulation channel associated with the identified stimulation site, stimulation management facility 304 may alternatively perform the dynamic designation and the dynamic determination in accordance with a narrow focused stimulation strategy. A “narrow focused stimulation strategy” is similar to the quadripolar with correction stimulation strategy described above, except that only two compensating electrodes (as opposed to three) are used when the identified stimulation site is associated with a boundary of the stimulation channel.
To illustrate an exemplary narrow focused stimulation strategy, reference is made to
Panel 1002-1 illustrates a scenario in which processing facility 302 identifies a stimulation site associated with electrode E2 as the stimulation site that is to be stimulated in order to represent an audio signal to a patient. In response, stimulation management facility 304 may dynamically designate, based on the identified stimulation site, electrode E2 as being a lone main electrode and electrodes E1 and E3 as being compensating electrodes. Stimulation management facility 304 may also dynamically determine, based on the identified stimulation site, an amount of main current 1004 to be applied to electrode E2, a first weighted amount of compensating current 1006-1 to be applied to electrode E1, and a second weighted amount of compensating current 1006-2 to be applied to electrode E3.
Stimulation management facility 304 may then direct cochlear implant 108 to stimulate the identified stimulation site by concurrently applying the determined amount of main current to electrode E2 and the determined weighted amounts of compensating current to electrodes E1 and E3. As shown, stimulation management facility 304 may direct cochlear implant 108 to abstain from applying current to electrode E4. By so doing, an excitation field 1008 generated by main current 1004 may be focused. For the sake of comparison, an excitation field 1010 caused by monopolar stimulation of electrode E2 in the absence of compensation current is also shown in panel 1002-1. As shown, excitation field 1008 is relatively more focused than excitation field 1010. In some cases, the degree of focusing may be narrower than that achieved in the quadripolar with correction stimulation strategy because fewer electrodes (i.e., two versus three) are used to focus excitation field 1008.
As another example of the narrow focused stimulation strategy, panel 1002-2 illustrates a scenario in which processing facility 302 identifies a stimulation site located midway between the stimulation sites associated with electrodes E2 and E3 as the stimulation site that is to be stimulated in order to represent an audio signal to a patient. In response, stimulation management facility 304 may dynamically designate, based on the identified stimulation site, electrodes E2 and E3 as being main electrodes and electrodes E1 and E4 as being compensating electrodes. Stimulation management facility 304 may also dynamically determine, based on the identified stimulation site, a first weighted amount of main current 1012-1 to be applied to electrode E2, a second weighted amount of main current 1012-2 to be applied to electrode E3, a first weighted amount of compensating current 1014-1 to be applied to electrode E1, and a second weighted amount of compensating current 1014-2 to be applied to electrode E4.
Stimulation management facility 304 may then direct cochlear implant 108 to stimulate the identified stimulation site by concurrently applying the determined weighted amounts of main current to electrodes E2 and E3, and the determined weighted amounts of compensating current to electrodes E1 and E4. By so doing, an excitation field 1016 generated by main current 1012-1 and 1012-2 may be focused. For the sake of comparison, an excitation field 1018 caused by conventional current steering between electrodes E2 and E3 in the absence of compensation current is also shown in panel 1002-2. As shown, excitation field 1016 is relatively more focused than excitation field 1018.
As another example of the narrow focused stimulation strategy, panel 1002-3 illustrates a scenario in which processing facility 302 identifies a stimulation site associated with electrode E3 as the stimulation site that is to be stimulated in order to represent an audio signal to a patient. In response, stimulation management facility 304 may dynamically designate, based on the identified stimulation site, electrode E3 as being a lone main electrode and electrodes E2 and E4 as being compensating electrodes. Stimulation management facility 304 may also dynamically determine, based on the identified stimulation site, an amount of main current 1020 to be applied to electrode E3, a first weighted amount of compensating current 1022-1 to be applied to electrode E2, and a second weighted amount of compensating current 1022-2 to be applied to electrode E4.
Stimulation management facility 304 may then direct cochlear implant 108 to stimulate the identified stimulation site by concurrently applying the determined amount of main current to electrode E3 and the determined weighted amounts of compensating current to electrodes E2 and E4. As shown, stimulation management facility 304 may direct cochlear implant 108 to abstain from applying current to electrode E1. By so doing, an excitation field 1024 generated by main current 1020 may be focused. For the sake of comparison, an excitation field 1026 caused by monopolar stimulation of electrode E3 in the absence of compensation current is also shown in panel 1002-3. As shown, excitation field 1024 is relatively more focused than excitation field 1026. In some cases, the degree of focusing may be narrower than that achieved in the quadripolar with correction stimulation strategy because fewer electrodes (i.e., two versus three) are used to focus excitation field 1024.
In some examples, three electrodes correspond to the stimulation channel associated with the identified stimulation site—a first electrode, a second electrode, and a third electrode sequentially disposed within the cochlea. The first electrode is the most apically disposed of the three electrodes and the third electrode is the most basally disposed of the three electrodes. In these examples, stimulation management facility 304 may perform the dynamic designation and the dynamic determination in accordance with an inverse steering stimulation strategy. As used herein, an “inverse steering stimulation strategy” is one in which stimulation management facility 304 dynamically designates, based on the identified stimulation site, the middle electrode (i.e., the second electrodes) as the main electrode and one or both of the flanking electrodes (i.e., the first and/or third electrode) as compensating electrodes.
To illustrate an exemplary inverse steering stimulation strategy, reference is made to
Panel 1102-1 illustrates a scenario in which processing facility 302 identifies a stimulation site associated with electrode E3 as the stimulation site that is to be stimulated in order to represent an audio signal to a patient. In response, stimulation management facility 304 may dynamically designate, based on the identified stimulation site, electrode E2 as being a lone main electrode and electrode E1 as being a lone compensating electrode. Stimulation management facility 304 may also dynamically determine, based on the identified stimulation site, an amount of main current 1104 to be applied to electrode E2 and an amount of compensating current 1106 to be applied to electrode E1.
Stimulation management facility 304 may then direct cochlear implant 108 to stimulate the identified stimulation site by concurrently applying the determined amount of main current to electrode E2 and the determined amount of compensating current to electrode E1. As shown, stimulation management facility 304 may direct cochlear implant 108 to abstain from applying current to electrode E3. By so doing, an excitation field 1108 generated by main current 1104 may be focused. For the sake of comparison, an excitation field 1110 caused by monopolar stimulation of electrode E3 in the absence of compensation current is also shown in panel 1102-1. As shown, excitation field 1108 is relatively more focused than excitation field 1110.
Compensating current 1106 may also shift a peak 1112 of excitation field 1108 to the right such that it is roughly located at the stimulation site associated with electrode E3. For the sake of comparison, a peak 1114 of excitation field 1110 is also indicated in panel 1102-1.
Panel 1102-2 illustrates a scenario in which processing facility 302 identifies a stimulation site associated with electrode E2 as the stimulation site that is to be stimulated in order to represent an audio signal to a patient. In response, stimulation management facility 304 may dynamically designate, based on the identified stimulation site, electrode E2 as being a lone main electrode and electrodes E1 and E3 as being compensating electrodes. Stimulation management facility 304 may also dynamically determine, based on the identified stimulation site, an amount of main current 1116 to be applied to electrode E2, a first weighted amount of compensating current 1118-1 to be applied to electrode E1, and a second weighted amount of compensating current 1118-2 to be applied to electrode E3.
Stimulation management facility 304 may then direct cochlear implant 108 to stimulate the identified stimulation site by concurrently applying the determined amount of main current to electrode E2 and the determined amounts of compensating current to electrodes E1 and E3. The compensating current 1118-1 and 1118-2 may focus an excitation field 1120 generated by main current 1116. For the sake of comparison, an excitation field 1122 caused by monopolar stimulation of electrode E2 in the absence of compensation current is also shown in panel 1102-2. As shown, excitation field 1120 is relatively more focused than excitation field 1122.
Panel 1102-3 illustrates a scenario in which processing facility 302 identifies a stimulation site associated with electrode E1 as the stimulation site that is to be stimulated in order to represent an audio signal to a patient. In response, stimulation management facility 304 may dynamically designate, based on the identified stimulation site, electrode E2 as being a lone main electrode and electrode E3 as being a lone compensating electrode. Stimulation management facility 304 may also dynamically determine, based on the identified stimulation site, an amount of main current 1126 to be applied to electrode E2 and an amount of compensating current 1128 to be applied to electrode E3.
Stimulation management facility 304 may then direct cochlear implant 108 to stimulate the identified stimulation site by concurrently applying the determined amount of main current to electrode E2 and the determined amount of compensating current to electrode E3. As shown, stimulation management facility 304 may direct cochlear implant 108 to abstain from applying current to electrode E1. By so doing, an excitation field 1130 generated by main current 1126 may be focused. For the sake of comparison, an excitation field 1132 caused by monopolar stimulation of electrode E1 in the absence of compensation current is also shown in panel 1102-3. As shown, excitation field 1130 is relatively more focused than excitation field 1132.
Compensating current 1128 may also shift a peak 1134 of excitation field 1130 to the left such that it is roughly located at the stimulation site associated with electrode E1. For the sake of comparison, a peak 1136 of excitation field 1132 is also indicated in panel 1102-3.
The inverse steering stimulation strategy described herein may advantageously use relatively few electrodes and may result in a relatively high degree of focusing, which may be beneficial when it is desirable to represent frequencies at or near the boundary of an analysis channel. The inverse steering stimulation strategy described herein may be beneficial for various other reasons. It should be noted that in some embodiments, the choice of the stimulation configuration may be influenced not only by energy corresponding to the channel, but also by activity on a plurality of neighboring channels. For example, if a relatively large spectral peak is spanning a few channels, then the optimal configuration may be selected within each channel to represent this peak.
In some examples, once processing facility 302 has divided an audio signal presented to a patient into a plurality of analysis channels each containing a frequency domain signal representative of a distinct frequency portion of the audio signal, stimulation management facility 304 may direct cochlear implant 108 to apply electrical stimulation representative of each frequency domain signal included in the plurality of analysis channels in accordance with a stimulation strategy that includes a degree of focusing that is analysis channel-dependent. Such a stimulation strategy may be referred to herein as an “array extension steering stimulation strategy.”
As shown in
As shown in
As shown in
The output of each mapping module 1310 is input into a current steering module 1312. The current steering module 1312 is also configured to receive the output of the frequency estimator 1306. In some examples, the current steering module 1312 is configured to determine appropriate weighting factors for current to be applied to electrodes 1302-1 and 1302-2. This determination may be based at least in part on the peak frequency estimate and the output of each of the mapping modules 1310. The weighting factors may be applied to the current using multiplication blocks 1314. In this manner, stimulation current may be delivered to a stimulation site located in between areas associated with electrodes 1302-1 and 1302-2.
The excitation field produced by the current steering electrodes 1302-1 and 1302-2 may be focused by applying compensating current simultaneously to one or more additional electrodes (referred to herein as compensating electrodes). To illustrate,
Implementation 1400 includes many of the same components as the implementation described in connection with
As shown in
While exemplary implementations 1300 and 1400 of current steering have been described herein, it will be recognized that other implementations of current steering may be additionally or alternatively used in connection with the systems and methods described herein as may serve a particular implementation.
In step 1502, a sound processor identifies a stimulation site within a cochlea of a patient that is to be stimulated in order to represent an audio signal presented to the patient, the stimulation site included within a plurality of stimulation sites associated with a stimulation channel corresponding to a plurality of electrodes. Step 1502 may be performed in any of the ways described herein.
In step 1504, the sound processor dynamically designates, based on the identified stimulation site, a first group of one or more electrodes included in the plurality of electrodes as a group of one or more main electrodes and a second group of one or more electrodes included in the plurality of electrodes as a group of one or more compensating electrodes. Step 1504 may be performed in any of the ways described herein.
In step 1506, the sound processor dynamically determines, based on the identified stimulation site, an amount of main current to be applied to each electrode included in the first group of one or more electrodes in order to represent the audio signal and an amount of compensating current to be applied to each electrode included in the second group of one or more electrodes to focus an excitation field created by the main current, the compensating current opposite in polarity compared to the main current. Step 1506 may be performed in any of the ways described herein.
In the preceding description, various exemplary embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the scope of the invention as set forth in the claims that follow. For example, certain features of one embodiment described herein may be combined with or substituted for features of another embodiment described herein. The description and drawings are accordingly to be regarded in an illustrative rather than a restrictive sense.
Claims
1. A system comprising:
- a processing facility that identifies a stimulation site within a cochlea of a patient that is to be stimulated in order to represent an audio signal presented to the patient, the stimulation site included within a plurality of stimulation sites associated with a stimulation channel corresponding to a plurality of electrodes; and
- a stimulation management facility communicatively coupled to the processing facility and that dynamically designates, based on the identified stimulation site, a first group of one or more electrodes included in the plurality of electrodes as a group of one or more main electrodes and a second group of one or more electrodes included in the plurality of electrodes as a group of one or more compensating electrodes, and dynamically determines, based on the identified stimulation site, an amount of main current to be applied to each electrode included in the first group of one or more electrodes in order to represent the audio signal and an amount of compensating current to be applied to each electrode included in the second group of one or more electrodes to focus an excitation field created by the main current, the compensating current opposite in polarity compared to the main current.
2. The system of claim 1, wherein the stimulation management facility directs a cochlear implant associated with the patient to stimulate the identified stimulation site by concurrently:
- applying the determined amount of main current to the first group of one or more electrodes; and
- applying the determined amount of compensation current to the second group of one or more electrodes.
3. The system of claim 1, wherein the plurality of electrodes comprises a first electrode, a second electrode, a third electrode, and a fourth electrode sequentially disposed within the cochlea, and wherein the stimulation management facility performs the dynamic designation and the dynamic determination in accordance with a quadripolar with correction stimulation strategy.
4. The system of claim 3, wherein:
- the identified stimulation site is in between a stimulation site associated with the second electrode and a stimulation site associated with the third electrode;
- the stimulation management facility performs the dynamic designation in accordance with the quadripolar with correction stimulation strategy by designating, based on the identified stimulation site being in between the stimulation site associated with the second electrode and the stimulation site associated with the third electrode, the second and third electrodes as being main electrodes included in the group of one or more main electrodes and the first and fourth electrodes as being compensating electrodes included in the group of one or more compensating electrodes; and
- the stimulation management facility performs the dynamic determination in accordance with the quadripolar with correction stimulation strategy by determining, based on the identified stimulation site being in between the stimulation site associated with the second electrode and the stimulation site associated with the third electrode, a first weighted amount of the main current to be applied to the second electrode in accordance with a current steering strategy, a second weighted amount of the main current to be applied to the third electrode in accordance with the current steering strategy, a first weighted amount of the compensating current to be applied to the first electrode, and a second weighted amount of the compensating current to be applied to the fourth electrode.
5. The system of claim 3, wherein:
- the identified stimulation site is associated with the second electrode;
- the stimulation management facility performs the dynamic designation in accordance with the quadripolar with correction stimulation strategy by designating, based on the identified stimulation site being associated with the second electrode, the second electrode as being a lone main electrode included in the group of one or more main electrodes and the first, third, and fourth electrodes as being compensating electrodes included in the group of one or more compensating electrodes; and
- the stimulation management facility performs the dynamic determination in accordance with the quadripolar with correction stimulation strategy by determining, based on the identified stimulation site being associated with the second electrode, the amount of main current to be applied to the second electrode, a first weighted amount of the compensating current to be applied to the first electrode, a second weighted amount of the compensating current to be applied to the third electrode, and a third weighted amount of the compensating current to be applied to the fourth electrode.
6. The system of claim 3, wherein:
- the identified stimulation site is associated with the third electrode;
- the stimulation management facility performs the dynamic designation in accordance with the quadripolar with correction stimulation strategy by designating, based on the identified stimulation site being associated with the third electrode, the third electrode as being a lone main electrode included in the group of one or more main electrodes and the first, second, and fourth electrodes as being compensating electrodes included in the group of one or more compensating electrodes; and
- the stimulation management facility performs the dynamic determination in accordance with the quadripolar with correction stimulation strategy by determining, based on the identified stimulation site being associated with the third electrode, the amount of main current to be applied to the third electrode, a first weighted amount of the compensating current to be applied to the first electrode, a second weighted amount of the compensating current to be applied to the second electrode, and a third weighted amount of the compensating current to be applied to the fourth electrode.
7. The system of claim 1, wherein the plurality of electrodes comprises a first electrode, a second electrode, and a third electrode sequentially disposed within the cochlea, and wherein the stimulation management facility performs the dynamic designation and the dynamic determination in accordance with an inverse steering strategy.
8. The system of claim 7, wherein:
- the identified stimulation site is associated with the first electrode;
- the stimulation management facility performs the dynamic designation in accordance with the quadripolar with correction stimulation strategy by designating, based on the identified stimulation site being associated with the first electrode, the second electrode as being a lone main electrode included in the group of one or more main electrodes and the third electrode as being a lone compensating electrode included in the group of one or more compensating electrodes; and
- the stimulation management facility performs the dynamic determination in accordance with the inverse steering strategy by determining, based on the identified stimulation site being associated with the first electrode, the amount of main current to be applied to the second electrode, and the amount of compensating current to be applied to the third electrode.
9. The system of claim 8, wherein the stimulation management facility directs a cochlear implant associated with the patient to stimulate the identified stimulation site by concurrently:
- applying the determined amount of main current to the second electrode;
- applying the determined amount of compensation current to the third electrode; and
- abstaining from applying current to the first electrode.
10. The system of claim 7, wherein:
- the identified stimulation site is associated with the second electrode;
- the stimulation management facility performs the dynamic designation in accordance with the quadripolar with correction stimulation strategy by designating, based on the identified stimulation site being associated with the second electrode, the second electrode as being a lone main electrode included in the group of one or more main electrodes and the first and third electrodes as being compensating electrodes included in the group of one or more compensating electrodes; and
- the stimulation management facility performs the dynamic determination in accordance with the inverse steering strategy by determining, based on the identified stimulation site being associated with the second electrode, the amount of main current to be applied to the second electrode, a first weighted amount of the compensating current to be applied to the first electrode, and a second weighted amount of the compensating current to be applied to the third electrode.
11. The system of claim 7, wherein:
- the identified stimulation site is associated with the third electrode;
- the stimulation management facility performs the dynamic designation in accordance with the quadripolar with correction stimulation strategy by designating, based on the identified stimulation site being associated with the third electrode, the second electrode as being a lone main electrode included in the group of one or more main electrodes and the first electrode as being a lone compensating electrode included in the group of one or more compensating electrodes; and
- the stimulation management facility performs the dynamic determination in accordance with the inverse steering strategy by determining, based on the identified stimulation site being associated with the first electrode, the amount of main current to be applied to the second electrode, and the amount of compensating current to be applied to the first electrode.
12. The system of claim 11, wherein the stimulation management facility directs a cochlear implant associated with the patient to stimulate the identified stimulation site by concurrently:
- applying the determined amount of main current to the second electrode;
- applying the determined amount of compensation current to the first electrode; and
- abstaining from applying current to the third electrode.
13. The system of claim 1, wherein the plurality of electrodes comprises a first electrode, a second electrode, a third electrode, and a fourth electrode sequentially disposed within the cochlea, and wherein the stimulation management facility performs the dynamic designation and the dynamic determination in accordance with a narrow focused steering stimulation strategy.
14. The system of claim 13, wherein:
- the identified stimulation site is associated with the second electrode;
- the stimulation management facility performs the dynamic designation in accordance with the narrow focused steering stimulation strategy by designating, based on the identified stimulation site being associated with the second electrode, the second electrode as being a lone main electrode included in the group of one or more main electrodes and the first and third electrodes as being compensating electrodes included in the group of one or more compensating electrodes; and
- the stimulation management facility performs the dynamic determination in accordance with the narrow focused steering stimulation strategy by determining, based on the identified stimulation site being associated with the second electrode, the amount of main current to be applied to the second electrode, a first weighted amount of the compensating current to be applied to the first electrode, and a second weighted amount of the compensating current to be applied to the third electrode.
15. The system of claim 14, wherein the stimulation management facility directs a cochlear implant associated with the patient to stimulate the identified stimulation site by concurrently:
- applying the determined amount of main current to the second electrode;
- applying the determined first weighted amount of the compensating current to the first electrode;
- applying the determined second weighted amount of the compensating current to the third electrode; and
- abstaining from applying current to the fourth electrode.
16. The system of claim 13, wherein:
- the identified stimulation site is associated with the third electrode;
- the stimulation management facility performs the dynamic designation in accordance with the narrow focused steering stimulation strategy by designating, based on the identified stimulation site being associated with the third electrode, the third electrode as being a lone main electrode included in the group of one or more main electrodes and the second and fourth electrodes as being compensating electrodes included in the group of one or more compensating electrodes; and
- the stimulation management facility performs the dynamic determination in accordance with the narrow focused steering stimulation strategy by determining, based on the identified stimulation site being associated with the third electrode, the amount of main current to be applied to the third electrode, a first weighted amount of the compensating current to be applied to the second electrode, and a second weighted amount of the compensating current to be applied to the fourth electrode.
17. The system of claim 16, wherein the stimulation management facility directs a cochlear implant associated with the patient to stimulate the identified stimulation site by concurrently:
- applying the determined amount of main current to the third electrode;
- applying the determined first weighted amount of the compensating current to the second electrode;
- applying the determined second weighted amount of the compensating current to the fourth electrode; and
- abstaining from applying current to the first electrode.
18. The system of claim 1, wherein:
- the processing facility identifies an additional stimulation site within the cochlea of the patient that is to be stimulated in order to represent an additional audio signal presented to the patient, the additional stimulation site included within the plurality of stimulation sites associated with the stimulation channel corresponding to the plurality of electrodes; and
- the stimulation management facility dynamically designates, based on the identified additional stimulation site, a third group of one or more electrodes included in the plurality of electrodes as a group of one or more main electrodes and a fourth group of one or more electrodes included in the plurality of electrodes as a group of one or more compensating electrodes, and dynamically determines, based on the identified additional stimulation site, an amount of main current to be applied to each electrode included in the third group of one or more electrodes in order to represent the additional audio signal and an amount of compensating current to be applied to each electrode included in the fourth group of one or more electrodes to focus an excitation field created by the main current applied to the third group of one or more electrodes, the compensating current applied to the fourth group of one or more electrodes opposite in polarity compared to the main current applied to the third group of one or more electrodes.
19. The system of claim 1, wherein:
- the processing facility identifies an additional stimulation site within the cochlea of the patient that is to be stimulated in order to represent an additional audio signal presented to the patient, the additional stimulation site included within the plurality of stimulation sites associated with the stimulation channel corresponding to the plurality of electrodes; and
- the stimulation management facility dynamically determines, based on the identified additional stimulation site, a different amount of main current to be applied to each electrode included in the first group of one or more electrodes in order to represent the additional audio signal and a different amount of compensating current to be applied to each electrode included in the second group of one or more electrodes to focus an excitation field created by the different amount of main current, the different amount of compensating current opposite in polarity compared to the different amount of main current.
20. The system of claim 1, wherein the processing facility identifies the stimulation site by:
- determining a frequency of a spectral peak associated with the audio signal and included in an analysis channel that corresponds to the frequency channel; and
- identifying a stimulation site that corresponds to the identified frequency.
21. The system of claim 1, wherein the plurality of electrodes includes one or more electrodes that define the stimulation channel and one or more electrodes adjacent to the one or more electrodes that define the stimulation channel.
22. The system of claim 1, wherein the first group of one or more electrodes and the second group of one or more electrodes do not overlap.
23. A system comprising:
- a processing facility that divides an audio signal presented to a patient into a plurality of analysis channels each containing a frequency domain signal representative of a distinct frequency portion of the audio signal, and
- a stimulation management facility communicatively coupled to the processing facility and that directs a cochlear implant associated with the patient to apply electrical stimulation representative of each frequency domain signal included in the plurality of analysis channels in accordance with a stimulation strategy that includes a degree of focusing that is analysis channel-dependent.
24. A method comprising:
- identifying, by a sound processor, a stimulation site within a cochlea of a patient that is to be stimulated in order to represent an audio signal presented to the patient, the stimulation site included within a plurality of stimulation sites associated with a stimulation channel corresponding to a plurality of electrodes;
- dynamically designating, by the sound processor based on the identified stimulation site, a first group of one or more electrodes included in the plurality of electrodes as a group of one or more main electrodes and a second group of one or more electrodes included in the plurality of electrodes as a group of one or more compensating electrodes; and
- dynamically determining, by the sound processor based on the identified stimulation site, an amount of main current to be applied to each electrode included in the first group of one or more electrodes in order to represent the audio signal and an amount of compensating current to be applied to each electrode included in the second group of one or more electrodes to focus an excitation field created by the main current, the compensating current opposite in polarity compared to the main current.
25. The method of claim 24, further comprising directing, by the sound processor, a cochlear implant associated with the patient to stimulate the identified stimulation site by:
- applying the determined amount of main current to the first group of one or more electrodes; and
- applying the determined amount of compensation current to the second group of one or more electrodes.
Type: Application
Filed: Nov 29, 2013
Publication Date: Nov 19, 2015
Inventors: Leonid M. Litvak (Los Angeles, CA), Michael S. Marzalek (Santa Rosa, CA)
Application Number: 14/651,625