Patent ID: 12186560

DETAILED DESCRIPTION

Sensory impulses relating to balance and spatial orientation are generated by the human vestibular system. These sensory impulses are perceived by the brain via the vestibulocochlear nerve and provide a sense of balance and spatial orientation. But disorders affecting the vestibular system (e.g., Ménière's disease, other bilateral vestibular disorders, or inflammation of vestibular anatomy) can cause vestibular deficiency by interfering with these sensory impulses, thereby negatively affect one's sense of balance and spatial orientation. Vertigo can also result.

Disclosed embodiments include vestibular stimulation prostheses for restoring vestibular function in recipients having vestibular deficiency. In an example, a body (e.g., a flexible a mesh-like body) is appended onto or within the recipient's ossicular chain such that the body directly interfaces with an oval window of an inner ear of the recipient. Electrical stimulation is provided using one or more electrodes of the body to stimulate the vestibular system (e.g., the otolith organs thereof) and thereby restore vestibular functioning. In an example, a stimulator device connected to the body via a lead is also implanted. The stimulator device can have a small and convenient form factor. In some instances, the stimulator device is a stand-alone device that is configured to provide stimulation to the recipient's vestibular system without respect to signals received from devices external to the recipient. In some implementations, the stimulator device can be a component of a sensory prosthesis (e.g., a cochlear implant or bionic eye) or another medical device.

The body of the vestibular stimulation prosthesis can interface directly with a recipient's oval window. In one example, the body is configured to be placed between the stapes and the oval window. In another example, the body also acts as a stapes prosthesis. For instance, the body can connect to the incus. In addition, the body can be configured to preserve inner ear anatomy. For instance, the body and the components thereof (e.g., the electrodes thereof) can be configured to avoid penetrating into the inner ear. This placement of the body within the ossicular chain can result in approximately 10 Decibels or less of hearing loss for the recipient due to attenuation of vibrations conducted to the oval window. However the hearing loss can be preferable in many instances compared to the potentially worse outcomes that can result from alternative approaches penetrating the inner ear (e.g., damaging hearing or vestibular anatomy).

Positioning the body proximate to the oval window can provide several advantages. First, the oval window is sufficiently close to the otolith organs to provide relatively easy targeting of stimulation to the otolith organs. Additionally, the stimulation signals from the electrodes can more easily penetrate through the oval window than other bony structure within the middle ear cavity (e.g., the temporal bone). This can allow for the use of relatively lower intensity stimulation and relatively lower collateral damage to tissue. Further, the placement proximate the oval window can be performed transtympanically, which is less invasive than traditional approaches through the temporal bone.

Disclosed embodiments further include particular electrode and body arrangements and designs for use with vestibular stimulation prostheses (see, e.g.,FIGS.3-20), particular coupling arrangements and designs for connecting the body with anatomy of the recipient (see, e.g.,FIGS.21-26), processes for implanting the vestibular stimulation prosthesis and providing therapeutic stimulation (see, e.g.,FIGS.27and28), example reference electrode configurations (see, e.g.,FIGS.29-38), and an example implementation of the vestibular stimulation prosthesis with a sensory prosthesis (see, e.g.,FIG.39).

As should be appreciated, while particular examples are illustrated and discussed herein, the disclosed vestibular stimulation prostheses and processes described herein can be integrated in any of a variety of ways in accordance with many embodiments of the invention. The discussion is not meant to suggest that the disclosed vestibular stimulation examples are only suitable for implementation within systems akin to that illustrated in and described herein. In general, additional configurations can be used to practice the methods and systems herein and/or some aspects described can be excluded without departing from the processes and systems disclosed herein.

Vestibular Stimulation Prosthesis

FIG.1illustrates a view of an example vestibular stimulation prosthesis100implanted relative to inner ear anatomy in accordance with certain embodiments herein. The vestibular stimulation prosthesis100is an apparatus configured to provide therapeutic stimulation to a vestibular system of a recipient. In the illustrated configuration, the vestibular stimulation prosthesis100includes a body110having one or more electrodes112. The body110is connected to a stimulator device150via a lead140. Other configurations of the vestibular stimulation prosthesis100are also possible.

The body110can be a carrier for one or more components of the vestibular stimulation prosthesis100. In particular, the body110be a carrier for one or more components for providing stimulation to the vestibular system, such as the one or more electrodes112. The body110can be configured to be placed proximate the oval window. The body110can include other components, such as one or more components for connecting the body110to the ossicular chain (e.g., the stapes, incus, or malleus thereof). Such connectors are described in more detail in relation toFIGS.20-25. The body110can further include one or more sensors (e.g., for sensing the vestibular system).

The body110can take any of a variety of forms. In an example, the body110is formed as a mesh. In an example, the mesh is relatively flexible. In an example, the body is formed with an elastomer, such as silicone. In an example, the body110is configured to conduct vibrations from the ossicular chain to the oval window. The body110can be configured to interface with the oval window. The body110can be configured to cover part of or the entirety of the oval window. The body110can be configured to cover the oval window in such a manner that one or more electrodes112are positioned to target vestibular anatomy of the recipient.

The one or more electrodes112are electrically-conductive components via which stimulation can be provided. The one or more electrodes112can have any of a variety of different shapes, sizes, profiles, and configurations. Example configurations of the electrodes112are shown inFIGS.3-17. Generally, the one or more electrodes112can be advantageously configured to resist penetrating the oval window when the body110is properly implanted. IN other examples, the one or more electrodes112can be configured to penetrating the oval window to a predetermined depth, avoiding anatomical damage of otolith organ.

The lead140is a component that electrically connects two or more components of the vestibular stimulation prosthesis100. In many examples, the lead140is a cable having one or more wires disposed within an insulated sheath. In the illustrated configuration, the lead140connects the stimulator device150to the body110. In such a configuration, the lead140can convey electrical stimulation signals from the stimulator device150to the body110(e.g., to the electrodes112thereof).

The stimulator device150can be a component of the vestibular stimulation prosthesis100that generates the stimulation signals that are to be applied to the vestibular system. The stimulator device150often includes a housing in which one or more components are disposed. An example, configuration of the stimulator device150is shown inFIG.2.

The figure further shows the vestibular stimulation prosthesis100disposed in relation to vestibular and auditory anatomy. Among the anatomy shown, is the ear canal, which is part of the auditory anatomy. Acoustic pressure or sound waves can be channeled into and through ear canal. Disposed across an end of ear canal is a tympanic membrane which vibrates in response to the sound wave. This vibration is coupled to oval window (also known as the fenestra ovalis), which is adjacent round window (not shown), through the bones of the middle ear. The bones of the middle ear are the malleus, the incus, and the stapes, collectively referred to as the ossicles or the ossicular chain. The ossicles are positioned in the middle ear cavity and serve to filter and amplify the sound wave103. The ossicles cause the oval window to articulate (e.g., vibrate) in response to the vibration of tympanic membrane. This vibration of the oval window sets up waves of fluid motion of the perilymph within cochlea. Such fluid motion, in turn, activates tiny hair cells (not shown) inside of cochlea. Activation of the hair cells causes appropriate nerve impulses to be generated and transferred through the spiral ganglion cells (not shown) and auditory nerve (not shown) to the brain (also not shown) where they are perceived as sound.

In addition to the auditory anatomy, vestibular anatomy is also shown: the vestibular canals (also known as the semicircular canals) and the otolith organs. The vestibular canals are three canals (known as the horizontal canal, the superior canal, and the posterior canal) that allow rotational movement to be sensed. The otolith organs, which include the utricle and saccule, allow linear movement to be sensed. Rotational and linear movement cause appropriate nerve impulses to be generated via the vestibular anatomy and transferred through the auditory nerve (not shown) to the brain (also not shown) where they are perceived as motion.

The human skull is formed from a number of different bones that support various anatomical features. These bones are omitted fromFIG.1to aid the viewer. The temporal bone is situated at the side and base of the recipient's skull. The temporal bone is covered by a portion of the recipient's skin, muscle, and fat, which can collectively be referred to as tissue. The temporal bone can be referred to as having a superior portion and a mastoid portion. The superior portion comprises the section of the temporal bone that extends superior to the auricle. That is, the superior portion is the section of the temporal bone that forms the side surface of the skull. The mastoid portion is positioned inferior to the superior portion and is the section of the temporal bone that surrounds the middle ear.

The various components of the vestibular stimulation prosthesis100can be disposed with reference to this anatomy. In particular, the illustrated configuration shows the body110(and thus the one or more electrodes112) disposed at least partially between the stapes and the oval window of a recipient's left or right auditory anatomy. In this position, the body110is further proximate the otolith organs to which stimulation can be delivered through the oval window. As illustrated, the body110covers only a portion of the oval window. In other examples, the body110can entirely cover the oval window. In addition, while the stimulator device150is illustrated as being located inferior to the cochlea, the stimulator device150can be located in any of a variety of locations. The stimulator device150is described in more detail in relation toFIG.2.

Stimulator Device

FIG.2illustrates an example implementation of the stimulator device150. As illustrated, the stimulator device includes an electronics module154and a battery158disposed within a housing152.

The housing152can be an encasement that surrounds and hermetically seals one or more components of the stimulator device150. In examples, the housing152comprises a biocompatible material. In examples, the housing152includes a header providing an interconnection between the lead140and one or more components within the stimulator device150(e.g., the electronics module154thereof).

The electronics module154can include one or more other components to provide vestibular stimulation functionality. In some examples, the electronics module154includes one or more components for receiving a signal from an external device and converting the signal into a stimulation signal. But in many examples, the electronics module154generates a stimulation signal without regard to a signal from an external device. In many examples, the stimulation signal is generated according to a predetermined stimulation schedule that defines when and at what intensity the stimulation is to be applied.

In some examples, the electronics module154includes one or more processors (e.g., central processing units) coupled to memory components (e.g., flash memory) storing instructions that when executed cause performance of an operation described herein. In examples, the electronics module154generates and monitors parameters associated with generating and delivering the stimulus (e.g., output voltage, output current, or line impedance). In examples, the electronics module154generates a telemetry signal that includes telemetry data based on one or more of the parameters. The electronics module154can send the telemetry signal to an external device or store the telemetry signal in memory for later use or retrieval.

As illustrated, the electronics module154can include a stimulator156. The stimulator156generates electrical stimulation signals for use in stimulating tissue. The stimulator156can use stimulation control signals generated by the electronics module154(e.g., based on a stimulation schedule) to generate electrical stimulation signals (e.g., current signals) for delivery to the recipient's vestibular anatomy via the one or more electrodes112. In this way, the vestibular stimulation prosthesis100electrically stimulates the recipient's vestibular anatomy (e.g., nerve cells thereof), in a manner that causes the recipient to perceive vestibular percepts. The stimulation can be bipolar stimulation or monopolar stimulation.

The battery158is a component configured to store power. The battery158includes, for example, one or more rechargeable or non-rechargeable batteries. In some examples, the stimulator device150can be configured to receive power from another device, such as an external device or another implanted device. The power stored by the battery158can be distributed to the other components of the stimulator device150as needed for operation.

The stimulator device150can be a standalone vestibular stimulation prosthesis. In other examples, the vestibular stimulation prosthesis100can be part of another implanted medical device to add vestibular stimulation capabilities to the device. For instance, the implanted medical device can be a sensory prosthesis relating to one or more of the recipient's senses. For example, the sensory prosthesis can be a prosthesis relating to one or more of the five traditional senses (vision, hearing, touch, taste, and smell) and/or one or more of the additional senses. The sensory prosthesis can be an auditory prosthesis medical device configured to treat a hearing-impairment of the recipient. Where the sensory prosthesis is an auditory prosthesis, the sensory prosthesis can take a variety of forms including a cochlear implant, an electroacoustic device, a percutaneous bone conduction device, a passive transcutaneous bone conduction device, an active transcutaneous bone conduction device, a middle ear device, a totally-implantable auditory device, a mostly-implantable auditory device, an auditory brainstem implant device, a hearing aid, a tooth-anchored hearing device, a personal sound amplification product, other auditory prostheses, and combinations of the foregoing (e.g., binaural systems that include a prosthesis for a first ear of a recipient and a prosthesis of a same or different type for the second ear). In examples, the sensory prosthesis can be or include features relating to bionic eyes. Technology disclosed herein can also be relevant to applications with devices and systems used in for example, sleep apnea management, tinnitus management, and seizure therapy. Technology disclosed herein can be used with sensory devices such as consumer auditory devices (e.g., a hearing aid or a personal sound amplification product). Additional details regarding implementation of the vestibular stimulation prosthesis100with another implanted medical device is described in relation toFIG.39.

The stimulator device150can be connected via the lead140to the body110for providing stimulation via the electrodes112. The body110and the electrodes can take any of a variety of different configurations, including those described in relation toFIGS.3-20.

In some examples, the stimulator device150(and the vestibular stimulation prosthesis100as a whole) can include one or more aspects of the devices, methods, and computer programs for generating one or more signals for the electrical stimulation of the saccule and utricle of a patient as described in WO 2017/081335, which is hereby incorporated by reference in its entirety for any and all purposes.

Body and Electrodes

FIG.3illustrates a front view of an example body110, andFIG.4illustrates a side view of the example body110ofFIG.3. In the illustrated configuration, the body110has an oval shape with a long axis being longer than a short axis. The thickness of the body110is less than the width of the body110, which is less than the length of the body110. The body110includes three electrodes112disposed linearly along the long axis. The three electrodes112protrude from the body110and have a dome shape. The electrodes112each have respective tips114, which are rounded. The roundness of the respective tips114contributes to the electrodes112resisting penetration into the oval window when the body110is implanted proximate the oval window. The lead140extends laterally from the body110. The illustrated configuration is just one example implementation and others are also possible.

As illustrated, the body110can define a first surface116and a second surface118. The first surface116can be a surface (e.g., a side or face of the body110) configured to be disposed proximate (e.g., configured to contact) oval window tissue of a recipient when the body110is implanted in the recipient. In many examples, the first surface116is the surface of the body110at which the electrodes112are disposed. The second surface118can be a surface of the body110configured to be disposed proximate (e.g., configured to contact) an ossicular chain of the recipient. In examples, the second surface118is a surface at which a coupling for connecting the body110to the ossicular chain is disposed (see, e.g., coupling400shown inFIGS.21-26).

The body110can take any of a number of different shapes. In examples, the body110can have the shape of an n-sided polygon, where n is an integer three or greater (e.g., a triangle, quadrilateral, pentagon, etc.), when viewed from the front of the body110. In examples, the body110can have the shape of an n-pointed star polygon, where n is an integer five or greater (e.g., a pentagram, a hexagram, heptagram, etc.), when viewed from the front of the body110. The corners of the body110can be rounded or sharp. In the elevation view ofFIG.4, the body110is flat. In other examples, the body110can have concavities, convexities, ridges, waves, or other structural features. In an example, a flexible body110is a body sufficiently flexible to conform to a shape of a recipient's oval window when implanted. The body110can be constructed using any of a variety of materials, such as elastomers (e.g., silicone).

Generally, the configurations of the body110can be selected to properly position the electrodes112to target vestibular anatomy to deliver therapeutic stimulation. For example, the body110can be sized and shaped to facilitate placement of the electrodes112proximate target tissue. The body110can be sized and shaped to facilitate useful contact between the body110and the oval window. In addition or instead, the configurations of the body110can be selected to facilitate the conduction of vibrations from the ossicular chain to the oval window. For instance, the body can be sized and shaped to do so. Further, the materials of the body110can be selected to have sufficient stiffness or other properties to be conducive to the transmission of vibrations to the oval window. Further, the body110can be configured to preserve inner ear anatomy of the recipient. For example, the body110can be configured to resist damaging inner ear anatomy (e.g., by having rounded or blunt shapes or protrusions). Example configurations of the body110(and its components) are shown inFIGS.5-11.

Body Configurations

FIG.5illustrates an example front view of the body110having an inner portion126and an outer portion128, andFIG.6illustrates a cross-section view ofFIG.5taken along the line6-6ofFIG.5. For ease of understanding, additional internal features of the body110are omitted fromFIGS.5and6(e.g., the lead140is omitted, as are internal wiring components connecting the lead to the electrodes112). In the illustrated example, the outer portion128surrounds the perimeter of the inner portion126(e.g., the outer portion128circumferentially surrounds the inner portion126). In other examples, the outer portion128can extend from (e.g., but need not necessarily surround) the inner portion126. The outer portion128can include fixation features to facilitate attaching the body110to the oval window or the ossicular chain. The inner portion126and the outer portion128can be formed from the same or different materials. In examples, the outer portion128can be formed from a softer material than the material of the inner portion126. In examples, the outer portion128has a decreased thickness compared to the inner portion126. In an example, the inner portion126can have a region (e.g., extending from a top of the inner portion126to a bottom of the inner portion126) having a thickness of approximately 3 mm or less, 2 mm or less, or 1 mm or less. The outer portion128can have a region (e.g., extending from a top of the outer portion128to a bottom of the outer portion128) having a thickness of approximately 2 mm or less 1.5 mm or less, 1 mm or less, or 0.5 mm or less.

As can be seen inFIG.6, the outer portion128can define a concavity124of the body110. The electrodes112can be disposed within the concavity124. In an example, the concavity124has a depth approximately equal to the height of the electrodes112. In an example, the concavity124is configured to form a seal with the oval window, the oval window niche, the temporal bone, other tissue, or combinations thereof. In examples, the body110can act as a diaphragm that vibrates in response to vibrations conducted from the ossicular chain and conducts the vibrations to the oval window.

FIGS.7and8illustrate side views of an example body110. In an example, the body110can have a shape like that ofFIG.7orFIG.8in cross section along a width or a length of the body110. As illustrated, the body110has a trapezoidal shape defining a concavity124and a convexity122. The sides of the body110defining the concavity124and the convexity122are substantially straight. The base of the concavity124and convexity122are also substantially straight.FIG.7shows the electrodes112disposed at the convex portion of the body110. In such an example, the concavity124can facilitate a connection between the body110and the ossicular chain. For example, the stapes can be configured to at least partially fit within the concavity124.FIG.8shows the electrodes112disposed at the concave portion of the body110. In an example, the concavity124can facilitate a connection between the body110and the oval window.

FIG.9illustrates a side view of an example body110. In an example, the body110can have a shape like that ofFIG.9in cross section. As illustrated, the body110has a rectangular shape defining a concavity124and a convexity122. The sides of the body110defining the concavity124and the convexity122are substantially straight and are approximately perpendicular to a base of the concavity124. The base of the concavity124and the base of the convexity122are also substantially straight. As illustrated, the electrodes112are disposed at the concavity124of the body110. In another configuration, the electrodes112can be disposed at the convexity122of the body110. In an example, the concavity124can facilitate a connection between the body110and the oval window.

FIGS.10and11illustrate example side view of an example body110. In an example, the body110can have a shape like that ofFIG.10orFIG.11in cross section. As illustrated, the body110has a curved shape defining a concavity124and a convexity122.FIG.10shows the electrodes112disposed at the convexity122of the body110. In such an example, the concavity124can facilitate a connection between the body110and the ossicular chain. For example, the stapes can be configured to at least partially fit within the concavity124.FIG.11shows the electrodes112disposed at the concavity124of the body110. In an example, the concavity124can facilitate a connection between the body110and the oval window.

Electrode Configurations

Just like the body110can take any of a variety of configurations, so too can the electrodes112take any number of shapes. Further, the electrodes112can be disposed in any of a variety of configurations on the body110. Such shapes and configurations can be selected to facilitate targeting particular vestibular anatomy, such as otolith organs, when the body110is implanted. The electrodes112can be embedded in the body110, can be disposed flush with a surface of the body110, can extend a surface of the body110(e.g., such as perpendicular to the surface of the body110or at an angle relative to the surface), can take other configurations, or can take combinations of multiple configurations. The electrodes112can be affixed to the body110. The electrodes112can also have any of a variety of different shapes or combinations of shapes. The electrodes112can be formed as part of an n-sided polygon or an n-pointed star polygon in shape or in cross-section where n is an integer three or greater. The electrodes112can each have a respective tip114having a particular configuration. For example, the tip114can be configured to resist penetrating oval window tissue, such as by having a blunt shape, thereby being configured to resist penetrating the oval window tissue when the body110is implanted proximate the oval window. In other examples, the tip114can be configured to penetrate the oval window tissue, such as by having a sharp shape configured to penetrate the oval window tissue when the body110is implanted proximate the oval window. In examples, the tip114can have a concavity or a convexity. Example configurations of the electrodes112are shown inFIGS.12-20.

FIGS.12and13illustrate side views of an example body110with electrodes112extending therefrom. In the illustrated configurations, the electrodes112have a triangular shape when viewed from at least one side. In examples, the electrodes112can be conical or shaped like pyramids having an n-sided base, where n is an integer three or greater (e.g., a triangular base pyramid, a square base pyramid, a pentagonal base pyramid, etc.). In examples, the electrodes112can be shaped like a triangular prism. The electrodes112are illustrated as having a pointed tip114. Such a tip114can be relatively sharp and configured to penetrate tissue. In other examples, the tip114can be relatively rounded and configured to resist penetrating tissue. InFIG.12, the electrodes112have a width greater than a length. In such a configuration, the electrodes112can be configured to resist penetrating tissue. In other examples, the electrodes112can be blade-like and have a relatively small depth such that the electrodes112are configured to penetrate tissue to a depth. InFIG.13, the electrodes112have a length greater than their width. In such a configuration, the electrodes112can be configured to penetrate tissue. In an example, the length of the electrodes is selected to resist penetrating the oval window, damaging auditory anatomy, damaging vestibular anatomy, damaging other tissue, or combinations thereof. In an example, the length of the electrodes is selected to penetrate the oval window to a depth of 2.5 mm or less, 2 mm or less, 1.5 mm, or less, 1 mm or less, or 0.5 mm or less. In addition, although the figures are described with reference to electrodes112, any one or more of the electrodes112described herein can be replaced with or operate as a sensor configured to obtain data relating to stimulation or other measurable data.

FIG.14illustrates a side view of an example body110with electrodes112extending therefrom. In the illustrated configuration, the electrodes112have a substantially rectangular shape when viewed from at least one side. The length of the electrodes112is longer than a width of the electrodes112. In examples, the electrodes112can be cylindrical or rectangular. As illustrated, the tip114of the electrodes112has a convex shape. The tip114can take the form of a bident (e.g., has a bifurcated tip) with two tines extending from the body of the electrode. In examples, each of the two tines can be separate electrodes112.

FIG.15illustrates a side view of an example body110with electrodes112. In the illustrated configuration, the electrodes112have a substantially rectangular shape when viewed from at least one side. In examples, the electrodes112can be cylindrical or rectangular. The length of the electrodes is shorter than a width of the electrodes. As illustrated, the tip114of each of the electrodes112is flat. The flat tip114can resist penetrating the oval window, damaging auditory anatomy, damaging vestibular anatomy, damaging other tissue, or combinations thereof.

FIGS.16-20illustrate example arrangements of electrodes112relative to a surface of the body110. The arrangement of the electrodes112can be selected to target vestibular anatomy with stimulation.

FIG.16illustrates a front view of an example body110with two electrodes112. In the illustrated configuration, the electrodes112are linearly disposed along the long axis of the body110. The electrodes112are disposed in locations equidistant from the short axis of the body110. In other examples, the electrodes112can be linearly disposed along the short axis of the body110. In examples, the electrodes112can be disposed in a line rotated along any angle relative to the long axis.

FIG.17illustrates a front view of an example body110with three electrodes112. In the illustrated configuration, the electrodes112are disposed in such a way to from vertexes of an equilateral triangle centered on the body110(e.g., an equilateral triangle centered where the long and short axes meet). The electrodes112can be disposed in such a way as to form any other kind of triangle on the body110(e.g., an isosceles triangle, a scalene triangle, a right tringle, an obtuse triangle, or an acute triangle). The triangle can be centered elsewhere on the body110and rotated to any angle (e.g., any angle θ, where θ is an integer between 0 and 360 degrees, inclusive) relative to the long axis.

FIG.18illustrates a front view of an example body110with four electrodes112. In the illustrated configuration, the electrodes112are disposed in such a way to from vertexes of a square centered on the body110. The electrodes112can be disposed in such a way as to form any other kind of rhombus on the body110(e.g., rectangles, squares, parallelograms or trapezoids). The rhombus can be centered elsewhere on the body110and can be rotated to any angle (e.g., any angle θ, where θ is an integer between 0 and 360 degrees, inclusive) relative to the long axis.

FIG.19illustrates a front view of an example body110with seven electrodes112. In the illustrated configuration, the electrodes112are disposed in such a way to from vertexes of a hexagon centered on the body110with an additional electrode112disposed at the center of the hexagon. While the illustrated electrodes112are disposed to form an equilateral and equiangular hexagon, the electrodes112can be disposed to form a non-equilateral and non-equiangular hexagon. The illustrated hexagon is centered at a center of the body110but can be centered elsewhere on the body110and can be rotated to any angle (e.g., any angle θ, where θ is an integer between 0 and 360 degrees, inclusive) relative to the long axis.

FIG.20illustrates a front view of an example body110with many electrodes112. The electrodes112can be disposed on the body in any of a variety of ways, such as at vertices of an n-sided polygon where n is an integer three or greater. The electrodes112can be disposed in other locations as well. For example, the electrodes112can be disposed to fill a region of the body110with electrodes a predetermined distance apart. In an example, the total surface area of the electrodes visible in a front view is greater than a total surface area of the body110visible in the front view.

As described above, the shapes and configurations of the electrodes112and the body110can be selected to facilitate targeting particular vestibular anatomy, such as otolith organs, when the body110is implanted. In many implementations, the body110further includes a coupling to facilitate the implantation of the body110, positioning of the electrodes112, and the targeting of vestibular anatomy.

Coupling

Examples of the vestibular stimulation prosthesis100can further include a coupling400configured to couple the body110with tissue of the recipient (e.g., the temporal bone or a bone of the recipient's auditory ossicles, such as one or more of the malleus, the incus, and the stapes). The coupling400can be further configured to receive and conduct vibrations from the ossicular chain to the body110for transmission to the oval window.

FIG.21illustrates a side view of an example body110having a coupling400extending from the second surface118of the body110. The coupling400can be a component configured to couple the body110with a bone of the recipient's auditory ossicles. The coupling400can take any of a variety of forms. In the illustrated configuration, the coupling400includes a connector402and one or more bases404.

The connector402can be the portion of the coupling400that couples with the bone or other tissue of the recipient. The connector402can take any of a variety of different forms, such as one or more clips, screws, hooks, clamps, fasteners, adhesives, cements (e.g., bone cement), other kinds of couplings, or combinations thereof. In an example, the connector402comprises a metal, such as titanium.

The base404can be the portion of the coupling400that links the body110with the connector402. In examples, the base404can facilitate the positioning of the connector proximate tissue (e.g., the ossicular chain) with the first surface116of the body110positioned proximate the oval window. In examples, the base404is adjustable to facilitate such positioning. For instance, the angle between the base404and the connector can be adjustable. Likewise, the angle between the base404and the body110can also be adjustable. Further, a length of the base404can be adjustable. Further still, the base404can include an adjustable or fixed bend to facilitate angling the body110relative to the connector402. In some examples, the base404is sized and shaped to mimic one or more portions of the ossicular chain. In some examples, the base404is configured to conduct vibrations form the connector402to the body110for transmission to the oval window. In an example, the connector402comprises an elastomer, such as silicone.

FIG.22illustrates an example coupling400. In the illustrated configuration, the coupling400has a connector402in the form of a hook and a base404in the form of an elongate section extending from the hook and terminating in the body110. In an example, the connector402and the base can be integral with each other. The connector402and the base404can be formed from the same material, such as a metal (e.g., titanium). As illustrated, the base404extends from the second surface118and is substantially perpendicular to the second surface118. The base404extends from a middle of the body110but could be disposed elsewhere. The hook of the connector can be configured to attach directly to a bone of the ossicular chain or a fixation element coupled to the bone (e.g., a screw disposed within the bone). In examples, the hook can be configured to pierce into the bone. The hook can form its own path through the bone or follow a pre-excavated path.

FIG.23illustrates an example coupling400. As inFIG.22, the coupling400has a connector402in the form of a hook and a base404in the form of an elongate section extending from the hook. But in the configuration illustrated inFIG.23, the base404extends from an area proximate an edge of the body110at a non-perpendicular angle to the body110. As illustrated, the base404further includes a section extending from the edge of the body110along at least a portion of the body110. In the illustrated configuration, the base404extends along the second surface118without being disposed within the body110. In an example, the base404can be welded, adhered, or otherwise fastened to the body110without the base404being disposed within the body110.

FIG.24illustrates an example coupling400. As inFIGS.22and23, the coupling400has a connector402in the form of a hook. But in the configuration illustrated inFIG.24, the base404takes the form of a pedestal extending from the second surface118. As illustrated, the base404is trapezoidal or frustoconical but can take other forms. Further, a section of the connector402extends into the base404for support. In an example, the base404can be integral with the body110or discrete from the body. In an example, the base404can be formed from the same material as the body110. In an example, the connector402is formed from a metal (e.g., titanium) and the base404is formed from an elastomer (e.g., silicone).

FIG.25illustrates an example coupling400. In the illustrated configuration, the coupling has a connector402in the form of a screw extending from the body110. In an example, such a configuration can be considered to lack a base404.

FIG.26illustrates an embodiment of an ossicular-bone-replacement configuration of the body110. In particular, as illustrated, the body110is implanted in the ossicular chain replacing the stapes (but in one or more other examples, one or more other bones of the ossicular chain can be partially or wholly replaced). The body110includes a coupling400sized and shaped to replace the stapes. In particular, the coupling400is sized to place the electrodes112proximate the oval window when the body110is implanted with the connector402of the coupling connected to the incus. For instance, the base404can be sized and shaped to reach from the incus to the oval window. In this configuration, the body110can be configured to conduct vibrations from the incus to the oval window.

Example Processes

FIG.27illustrates an example process200for implanting and using a vestibular stimulation prosthesis. The process200can begin with operation210.

Operation210includes surgically accessing an implantation area in a recipient. For instance, a clinician can form an incision in tissue proximate a location where the vestibular stimulation prosthesis100is to be implanted and remove tissue to expose an implantation area. The incision can be sized and shaped to allow for the performance of operations220and230through the incision. In some examples, surgically accessing the implantation area includes performing a mastoidectomy. The operation can further include enlarging a posterior tympanotomy, which can include exposing the oval window, such as by enlarging superiorly the posterior tympanotomy. In some examples, surgically accessing the implantation area includes identifying the stapes, as well as the anterior and posterior crura of the stapes and the footplate of the stapes, which contacts the oval window. The facial nerve of the recipient proximate the oval window can also be identified.

In some examples, operation210further includes excavating ossicular chain tissue form a location for implanting a body110. For instance, using an excavating tool (e.g., a carbon dioxide laser) or a surgical drill, some or all of the footplate of the stapes is removed to make room for the body110. In some instances, the incus is removed to make room to place the body110. In some instances, the ligaments of the footplate are kept in position proximate the oval window. Following operation210, the flow can move to one or both of operation220and operation230.

Operation220includes placing one or more electrodes112of the body110proximate the recipient's oval window. This can include placing the body110partially or entirely on the oval window of the recipient. In some examples, the body110contacts the temporal bone surrounding the oval window. The placing of the electrodes112can include placing the electrodes such that they do or do not pierce the oval window. In examples, the electrodes112are inserted through the oval window to a depth of 2.5 mm or less, 2 mm or less, 1.5 mm, or less, 1 mm or less, 0.5 mm or less. In some examples, the electrodes112are inserted into the oval window to a depth less than a depth to which auditory and vestibular anatomy is damaged by the electrodes112during insertion (e.g., damaged in a way to cause loss of hearing or vestibular function, respectively). In some examples, a portion of the body110at which the electrodes112are disposed is positioned such that the electrodes face the area where the recipient's otolith organs are believed to be disposed.

Operation230includes implanting a body110at least partially in contact with an ossicular chain of the recipient. Placing the body110in contact with the ossicular chain can include connecting the body110to one or more of the bones of the recipient's ossicular chain. This can include connecting the coupling400to the bone. In addition, in some recipients, the facial nerve may impinge on the implantation area. In such instances, a material (e.g., foam) can be placed between the implanted body110and the impinging facial nerve.

Following operations220and230, the flow can move to operation240. Operation240includes finishing the implantation procedure. Finishing the implantation procedure can include closing one or more incisions made to access the implantation area. Following operation240, the flow can move to operation250.

Operation250includes calibrating the vestibular stimulation prosthesis100. This operation can be performed at various times and can be performed various numbers of times. For instance, the vestibular stimulation prosthesis100can be calibrated before or during implantation, such as to confirm appropriate functioning of the vestibular stimulation prosthesis100prior to implantation or to confirm appropriate placement of the electrodes112prior to operation240. The calibration can include performing vestibular response telemetry. Vestibular response telemetry can be used to confirm that one or more of the electrodes112are able to provide appropriate stimulation (e.g., to the vestibular tissue, such as nerve tissue). The vestibular response telemetry can include providing stimulation and measuring a response to the stimulation to determine whether placement of the electrodes112is appropriate. If the placement is inappropriate, the body110can be repositioned. In some examples, the vestibular response telemetry is used to determine which one or more electrodes of the one or more electrodes112is best able to stimulate target anatomy. Those one or more electrodes best able to stimulate the target anatomy can be selected as the electrodes to provide stimulation and the remaining electrodes can be (at least initially) deactivated. In many examples, additional calibration is performed subsequent to the finishing of the implantation procedure.

In examples, at least one month after implantation, the performance of the vestibular stimulation prosthesis100is tested. In an example, the recipient is asked to stand with their legs together and looking forward. Stimulation is provided by the vestibular stimulation system. The stimulation level of the stimulation provided can begin at a relatively low level. The stimulation level of the stimulation provided by the vestibular stimulation prosthesis100is then increased while the recipient's posture is poor or exhibits signs of poor balance (e.g., the recipient is swaying or shaking). When the recipient's posture and/or balance improves, the increase to the stimulation is stopped. Further, the recipient's subjective reports of their own perception of balance can used to determine whether to stop increasing stimulation levels. The stimulation level provided by the vestibular stimulation prosthesis100that ameliorates the recipient's balance can then be set such that the vestibular stimulation prosthesis100provides that level of stimulation going forward. The stimulation level can include a rate of stimulation. In examples, the stimulation rate is within the range of 200 Hz to 1000 Hz. Other levels are also possible. Further, while the electrodes112can be configured to provide a same stimulation rate or level, they need not. For instance, one electrode112can provide stimulation at a rate of 900 Hz and other electrodes112can provide stimulation at a rate of 500 Hz. Following operation250, the flow can move to operation260.

Operation260includes providing therapeutic stimulation with the vestibular stimulation prosthesis100. This operation260can include providing therapeutic stimulation to the vestibular system, as well as conducting sound vibrations to the oval window or associated tissue. After calibration, the vestibular stimulation prosthesis100can provide therapeutic stimulation to the recipient. This can include the vestibular stimulation prosthesis100providing stimulation according to a schedule generated based at least in part on the calibration of the vestibular stimulation prosthesis. Providing the therapeutic stimulation can include providing stimulation continuously to the recipient. Providing the therapeutic stimulation can include providing the stimulation periodically. Providing the stimulation periodically can include providing an amount of stimulation every approximately forty minutes to one hour for a therapeutic amount of time.

In an example, the operation260includes one or more operations described in relation toFIG.27, which describes an example process300stimulating vestibular tissue of a recipient. In an example, the process300begins with operation310.

Operation310includes conducting vibrations from an ossicular chain to an inner ear of the recipient. In an example, the body110of the vestibular stimulation prosthesis100can conduct the vibrations from a bone of the ossicular chain (e.g., incus, malleus, or stapes). A connector402of the body can connect to the bone and receive the vibrations. The connector402can conduct the vibrations to the base404. The base404can conduct the vibrations to the portion of the body110that contacts the oval window. In some examples, the vibrations are conducted via the one or more electrodes112to the oval window. In some examples, the vestibular stimulation prosthesis100can attenuate the vibrations received from the ossicular chain. The attenuation can, in some examples, cause a measurable (but not necessarily total) hearing loss in the recipient.

The method further includes operation320. In the illustrated example, operation320follows operation310, but in most implementations the operations occur without respect to the timing of the other. For example operation310can occur passively while the vestibular stimulation prosthesis100is implanted and operation320can occur according to a schedule.

Operation320includes generating a stimulation signal. In examples, the stimulation signal is generated by the stimulator156. The stimulation signal can be, for example, an electrical stimulation signal. The stimulator156can generate the stimulation signal based on a schedule or program. In other examples, the stimulator156generates the stimulation signal based on input from another component of the stimulator device150(e.g., a processor thereof) or based on input from another device of the vestibular stimulation prosthesis100(e.g., an external device). Generating the stimulation signal can include generating a stimulation signal selected to treat a vestibular condition of the recipient. Following operation320, the flow can move to operation330.

Operation330includes transmitting the stimulation signal to the one or more electrodes112. The transmitting can include transmitting the stimulation signal through a wired (e.g., via the lead140) or wireless connection between the stimulator156and the one or more electrodes112. In examples, a same stimulation signal can be sent to all of the electrodes112. In other examples, different stimulation signals are applied to different electrodes. In some examples, certain of the electrodes can be selectively activated to target stimulation at a particular anatomical location (e.g., to target vestibular anatomy through the oval window). In some examples, the one or more electrodes112are selectively activated or deactivated. Following operation330, the flow can move to operation340.

Operation340includes stimulating vestibular tissue of the recipient. For example, the one or more electrodes112can provide the stimulation using the received stimulation signal. In examples the vestibular tissue stimulated includes one or more of the vestibular canals or one or more of the otolith organs (e.g., the utricle and the saccule). In examples, stimulating vestibular tissue includes stimulating one or more nerves associated with the vestibular system, such as the vestibulocochlear nerve. The operation can include providing electrical stimulation through an oval window of the recipient.

Reference Electrodes

Disclosed examples can also include a reference electrode system500for affixing a reference electrode to bony structure of middle ear anatomy. The use of a reference electrode in the middle ear with the vestibular stimulation prostheses100described herein can provide advantages. For example, the use of the reference electrode system500can facilitate current steering, (e.g., so that stimulation currents can be more precisely applied to their intended targets). Although described herein in the context of a vestibular stimulation system, the reference electrodes described herein can be used in addition to or instead of the reference electrodes for inner ear stimulation devices described in U.S. 2012/0078337, entitled “Reference electrodes for inner ear stimulation devices”, which is hereby incorporated herein by reference for any and all purposes. Reference electrodes for heritage inner ear stimulation devices have commonly been affixed between the skull and the muscle and are not implanted within the middle ear cavity.

FIG.29illustrates a side view of an example reference electrode system500affixed to tissue. The illustrated reference electrode system500includes a reference electrode510, a reference electrode lead520coupled to and extending from the reference electrode510, and a reference electrode fastener530that fastens the reference electrode510to tissue. The reference electrode lead520can be a cable that electrically connects the reference electrode510to another component (e.g., the stimulator device150). The tissue can be any of a variety of tissue. In an example the tissue is tissue of the middle ear or inner ear. The tissue can be a bone of the ossicular chain or temporal bone located within the middle ear.

The reference electrode fastener530is a component configured to fasten the reference electrode510to tissue. The fastener530can take any of a variety of different forms, such as one or more clips, screws, hooks, clamps, fasteners, adhesives, cements (e.g., bone cement), other kinds of couplings, or combinations thereof. In an example, the fastener530comprises a metal, such as titanium. In some examples the fastener530is conductive to facilitate the performance of the reference electrode510. In other examples, the fastener530is non-conductive. The reference electrode fastener530is a screw that passes through the reference electrode (e.g., through an opening defined by the reference electrode510). The shaft of the screw extends primarily on a first tide of the reference electrode510(e.g., below the reference electrode510in the illustrated configuration) and the head of the screw extends primarily on a second surface of the reference electrode (e.g., above the reference electrode in the illustrated configuration). In examples, the reference electrode fastener530can be configured to form a path into tissue (e.g., by having a self-tapping feature or a piercing structure). In examples, the reference electrode fastener530is configured to follow a pre-formed hole through tissue (e.g., a path formed via a drill) formed into the target tissue.

The reference electrode510can be an electrode configured to act as a reference electrode for a device or system, such as the vestibular stimulation prosthesis100. The reference electrode510can take any number of shapes and can be disposed in any of a variety of configurations. Such shapes and configurations can be selected to facilitate contacting particular tissue, such as middle or inner ear anatomy, when the reference electrode system500is implanted. The reference electrode510can have any of a variety of different shapes or combinations of shapes. The reference electrode510can be formed as part of an n-sided polygon or an n-pointed star polygon in shape or in cross-section. The reference electrode510can include one or more structural features, such as protrusions, concavities, convexities, tips, other structures, or combinations thereof. For example, the reference electrode510can be configured to resist or promote penetrating of tissue, such as by having a blunt shape or a sharp structure, respectively. Example configurations of the reference electrode510are shown inFIGS.30-38.

FIG.30illustrates a first example top or bottom view of the reference electrode system500ofFIG.29with the tissue and the reference electrode fastener omitted530. The illustrated reference electrode510defines an opening512. The opening512can be a region lacking material. The opening512can be sized and shaped to be configured to receive the reference electrode fastener530. For example, as illustrated, the reference electrode510has a washer shape with the opening512being an area through which a fastening screw can pass to fasten the reference electrode to tissue. As illustrated, the opening512is substantially centered in the reference electrode510and is surrounded by the reference electrode510on all sides when viewed down an axis of the opening512.

FIG.31illustrates a second example top or bottom view of the reference electrode system500ofFIG.29with the tissue and the reference electrode fastener omitted530. Like the reference electrode510ofFIG.30, the reference electrode510illustrated inFIG.31defines an opening512. But this opening512is not completely surrounded by the reference electrode510on all sides when viewed down an axis of the opening. In the illustrated configuration, the reference electrode510is U-shaped. This configuration of the electrode510can facilitate the reference electrode510being slipped onto an existing reference electrode fastener or clipping the reference electrode510onto existing anatomy.

FIG.32illustrates an example implementation of reference electrode510having a triangular shape. The reference electrode510can have a point configured to pierce tissue. The triangular shape can be configured to pierce tissue during implantation of the reference electrode510to facilitate affixing the reference electrode510in tissue.

FIG.33illustrates an example implementation of reference electrode510having an arrowhead-like shape. The reference electrode510is triangular in shape. The reference electrode510can have a point configured to pierce tissue. The illustrated reference electrode510further includes one or more fins514at a proximal region of the reference electrode510. The fins514can be configured to pierce or slice tissue during implantation of the reference electrode510to facilitate affixing the reference electrode510in tissue.

FIG.34illustrates an example implementation of reference electrode510having a harpoon-tip-like shape. The reference electrode510is triangular in shape with a point configured to pierce tissue. The illustrated reference electrode510further includes one or more barbs516extending proximally from a region near a tip of the reference electrode. The one or more barbs516can be configured to resist the removal of the reference electrode and thereby facilitate affixing the reference electrode510in tissue.

FIG.35illustrates an example implementation of reference electrode510having a barbed-arrowhead-like shape. The reference electrode510is triangular in shape with a point configured to pierce tissue. The illustrated reference electrode510further includes a plurality of rows of barbs516extending proximally from a region near a tip of the reference electrode. The one or more barbs516can be configured to resist the removal of the reference electrode and thereby facilitate affixing the reference electrode510in tissue.

FIG.36illustrates an example implementation of a reference electrode510having a reference electrode fastener530configured as a clip. For example, the reference electrode fastener530can clip the reference electrode510to target anatomy. As illustrated, the reference electrode fastener530includes a spring518that forces apart a proximal portion of the reference electrode fastener530, which forces together a distal portion of the fastener530at which the reference electrode510is disposed. The reference electrode fastener530can have a resting closed state. For instance, absent an outside force, the spring518causes the distal portion of the fastener530to close together. A clinician can force apart the distal portion by pressing the proximal portion of the fastener530together.

FIG.37illustrates an example implementation of a reference electrode510having a reference electrode fastener530configured as a clip. For example, the reference electrode fastener530can be clip the reference electrode510to target anatomy. As illustrated, the reference electrode fastener530includes a spring518that forces together a distal portion of the reference electrode fastener530at which the reference electrode510is disposed, which forces apart a distal portion of the fastener530. The reference electrode fastener530can have a resting closed state. For instance, absent an outside force, the spring518causes the distal portion of the fastener530to close together. A clinician can force apart the distal portion by pressing the proximal portion of the fastener530together.

FIG.38illustrates an example configuration of the reference electrode system500in which the reference electrode system500can extend an existing reference electrode560. In the illustrated configuration, the distal portion of the reference electrode lead520is electrically coupled to the reference electrode510and a proximal portion of the reference electrode lead is coupled to a reference electrode connector550. The reference electrode connector550can be configured to couple with an existing reference electrode560to electrically connect the existing reference electrode560with the reference electrode510. In this manner, the reference electrode system500can act as an extension to an existing reference electrode560to add additional length or fixation capabilities.

FIG.39illustrates an example sensory prosthesis that can benefit from use of the technologies disclosed herein: a cochlear implant system610. The cochlear implant system610includes an implantable component644typically having an internal receiver/transceiver unit632, a stimulator unit620, and an elongate lead618. The internal receiver/transceiver unit632permits the cochlear implant system610to receive signals from and/or transmit signals to an external device650. The external device650can be a button sound processor worn on the head that includes a receiver/transceiver coil630and sound processing components. Alternatively, the external device650can be just a transmitter/transceiver coil in communication with a behind-the-ear device that includes the sound processing components and microphone.

The implantable component644includes an internal coil636, and preferably, a magnet (not shown) fixed relative to the internal coil636. The magnet can be embedded in a pliable silicone or other biocompatible encapsulant, along with the internal coil636. Signals sent generally correspond to external sound613. The internal receiver/transceiver unit632and the stimulator unit620are hermetically sealed within a biocompatible housing, sometimes collectively referred to as a stimulator/receiver unit. Included magnets (not shown) can facilitate the operational alignment of an external coil630and the internal coil636, enabling the internal coil636to receive power and stimulation data from the external coil630. The external coil630is contained within an external portion. The elongate lead618has a proximal end connected to the stimulator unit620, and a distal end646implanted in a cochlea640of the recipient. The elongate lead618extends from stimulator unit620to the cochlea640through a mastoid bone619of the recipient. The elongate lead618is used to provide electrical stimulation to the cochlea640based on the stimulation data. The stimulation data can be created based on the external sound613using the sound processing components and based on the sensory prosthesis settings. As illustrated, the stimulator unit620further includes the stimulator156configured to deliver stimulation to vestibular tissue of the recipient via electrodes of the body110disposed proximate the oval window of the recipient. The lead140connects the stimulator156to the electrodes of the body110.

In certain examples, the external coil630transmits electrical signals (e.g., power and stimulation data) to the internal coil636via a radio frequency (RF) link. The internal coil636is typically a wire antenna coil having multiple turns of electrically insulated single-strand or multi-strand platinum or gold wire. The electrical insulation of the internal coil636can be provided by a flexible silicone molding. Various types of energy transfer, such as infrared (IR), electromagnetic, capacitive and inductive transfer, can be used to transfer the power and/or data from external device to cochlear implant. While the above description has described internal and external coils being formed from insulated wire, in many cases, the internal and/or external coils can be implemented via electrically conductive traces.

Other sensory prostheses can benefit from technologies described herein. For example, the technology disclosed herein can be implemented with a direct acoustic stimulator prosthesis configured to generate vibrations and conduct the vibrations to move perilymph in scala tympani to activate hair cells to cause hearing percepts. Such a stimulator can include an actuator, a stapes prosthesis and a coupling element connecting the actuator to the stapes prosthesis. In an example, the prosthesis stimulation arrangement can be implanted and/or configured such that a portion of stapes prosthesis abuts a recipient's round or oval window. In examples, the portion of the prosthesis that abuts the oval window can include one or more electrodes112described herein for stimulating vestibular anatomy.

As should be appreciated, while particular uses of the technology have been illustrated and discussed above, the disclosed technology can be used with a variety of devices in accordance with many examples of the technology. The above discussion is not meant to suggest that the disclosed technology is only suitable for implementation within systems akin to that illustrated in the figures. For examples, while certain technologies described herein were primarily described in the context of auditory prostheses (e.g., cochlear implants), technologies disclosed herein are applicable to medical devices generally (e.g., medical devices providing pain management functionality or therapeutic electrical stimulation, such as deep brain stimulation). In general, additional configurations can be used to practice the processes and systems herein and/or some aspects described can be excluded without departing from the processes and systems disclosed herein. Further, the techniques described herein can be applicable to determining a recipient's response to other stimuli, such as visual stimuli, tactile stimuli, olfactory stimuli, taste stimuli, or another stimuli. Likewise, the devices used herein need not be limited to auditory prostheses and can be other medical devices configured to support a human sense, such as bionic eyes.

This disclosure described some aspects of the present technology with reference to the accompanying drawings, in which only some of the possible aspects were shown. Other aspects can, however, be embodied in many different forms and should not be construed as limited to the aspects set forth herein. Rather, these aspects were provided so that this disclosure was thorough and complete and fully conveyed the scope of the possible aspects to those skilled in the art.

As should be appreciated, the various aspects (e.g., portions, components, etc.) described with respect to the figures herein are not intended to limit the systems and processes to the particular aspects described. Accordingly, additional configurations can be used to practice the methods and systems herein and/or some aspects described can be excluded without departing from the methods and systems disclosed herein.

Similarly, where steps of a process are disclosed, those steps are described for purposes of illustrating the present methods and systems and are not intended to limit the disclosure to a particular sequence of steps. For example, the steps can be performed in differing order, two or more steps can be performed concurrently, additional steps can be performed, and disclosed steps can be excluded without departing from the present disclosure. Further, the disclosed processes can be repeated.

Although specific aspects were described herein, the scope of the technology is not limited to those specific aspects. One skilled in the art will recognize other aspects or improvements that are within the scope of the present technology. Therefore, the specific structure, acts, or media are disclosed only as illustrative aspects. The scope of the technology is defined by the following claims and any equivalents therein.