Neurostimulation and sensing system for auditory and non-auditory activation

Abstract

The present disclosure generally relates to auditory nerve stimulation to produce sound perception in the brain of a subject, such as an animal or human. In one form, a system includes an implantable electrode array that includes a plurality of spaced apart microneedles. The system also includes a first electrical lead electrically coupled to and extending from the implantable electrode array, and an auditory signaling device configured to generate one or more electrical signals representative of communications received from an external processor. The interposer is configured to electrically couple the implantable electrode array and the auditory signaling device in an arrangement in which one or more electrical signals generated by the auditory signaling device can be transmitted through the first electrical lead to the implantable electrode array. Various novel stimulation strategies, such as position modulated stimulation signals, may be employed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 426,551, filed on November 18, 2022, the entire contents of which are incorporated herein by reference. Federally Sponsored Research Statement

[0002] This invention was made with government support under Contract No. UG3NS107688 awarded by the National Institutes of Health. The government has certain rights in this invention. Technical Field

[0003] The present disclosure relates to medical implant devices, such as brain implants. Background Art

[0004] Advances in medical science have made it possible to sense and / or modulate neural tissue, including the auditory nerve. These advances have allowed scientists and researchers to observe systems like the auditory system in great detail. However, the art demands more sophisticated neural implants capable of more complex interactions with neural tissue. Therefore, there is a need for brain implant designs that improve the ability to interact with neural tissue, such as the auditory nerve, and that can do so reliably. Summary of the Invention

[0005] The present disclosure relates generally to neuroscience and, more particularly, but not exclusively, to auditory nerve stimulation to produce sound perception in the brain of a subject, such as an animal or a human. In one aspect, an implantable electrode array comprising a plurality of spaced-apart microneedles can be implanted into the auditory nerve bundle of an animal or a human and stimulate the auditory nerve in response to receiving an electrical signal representative of an observed sound.

[0006] Hearing-impaired individuals can benefit from the use of hearing aids or cochlear implants. However, further contributions are still needed in this area of ​​technology, particularly in the advancement of auditory nerve implants that can completely bypass the ear structure.

[0007] The claimed subject matter is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is provided merely to illustrate examples in which the disclosure may be utilized.

[0008] In one embodiment, a system includes an implantable electrode array comprising a plurality of spaced-apart microneedles. The system also includes a first electrical lead electrically coupled to and extending from the implantable electrode array; and an auditory signaling device configured to generate one or more electrical signals representative of observed sounds. An interposer is configured to electrically couple the implantable electrode array and the auditory signaling device in an arrangement wherein the one or more electrical signals generated by the auditory signaling device can be transmitted to the implantable electrode array via the first electrical lead.

[0009] In another embodiment, a device includes an implantable electrode array comprising a plurality of spaced-apart microneedles; an electrical lead electrically coupled to and extending from the implantable electrode array and comprising a plurality of wires; and an interposer comprising a plurality of contact pads. One or more wires of the plurality of wires of the electrical lead can be individually and electrically coupled to corresponding contact pads of the plurality of contact pads.

[0010] Some embodiments described herein may include three-dimensional electrode structures. An example of such a system is described in U.S. Patent 5,215,088, filed on November 7, 1989, entitled "Three-Dimensional Electrode Device" (the "'088 Patent"), the disclosure of which is incorporated herein by reference in its entirety. Some embodiments described herein may interact with already implanted three-dimensional electrode structures, such as those described in the '088 Patent.

[0011] In yet another embodiment, a method includes providing a system comprising:

[0012] an implantable electrode array comprising a plurality of spaced-apart microneedles;

[0013] a first electrical lead electrically coupled to and extending from the implantable electrode array;

[0014] an auditory signaling device configured to generate one or more electrical signals representative of the observed sounds; and

[0015] An interposer is configured to electrically couple the implantable electrode array and the auditory signal device in an arrangement in which one or more electrical signals generated by the auditory signal device can be transmitted to the implantable electrode array through the first electrical lead.

[0016] The method also includes implanting the implantable electrode array into an auditory nerve of a person and positioning the auditory signaling device at a discrete location on the person spaced apart from the implantable electrode array.

[0017] In alternative embodiments, assemblies, systems, devices, and apparatus related to auditory nerve stimulation are provided.

[0018] Some embodiments of the devices and methods described herein may be used for in vivo implementation, ie, interfacing with the nervous system of a living organism. Some embodiments of the devices and methods described herein may be used to interface with the nervous system of a living organism that is awake and performing behavior.

[0019] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the disclosed subject matter, nor is it intended to be used as an aid in determining the scope of the disclosed subject matter.

[0020] Additional features and advantages will be set forth in the following description, and in part will be apparent from the description, or may be learned by practice of the invention. These features and advantages may be realized and obtained by the instruments and combinations particularly pointed out in the appended claims. These and other features of the invention will become more apparent from the following description and the appended claims, or may be learned by practice of the invention as set forth below. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of a system configured for auditory nerve stimulation.

[0022] Figure 2 yes Figure 1 Side view of the implantable electrode array of the system.

[0023] Figure 3 It includes multiple microneedles Figure 2 A perspective view of a portion of an implantable electrode array.

[0024] Figure 4 yes Figure 3 A side view of a portion of an implantable electrode array is shown.

[0025] Figure 5 yes Figure 1 A magnified photographic image of an implantable electrode array of the system, with electrical leads extending from the implantable electrode array.

[0026] Figure 6 is provided by the interposer Figure 1 A schematic diagram of the electrical connections between the components of the system.

[0027] Figure 7 is configured for delivery and implantation Figure 1 A plan view of an implantable electrode array device of the system.

[0028] Figures 8A to 8C yes Figure 7 A perspective view of an alternative form of the end of the instrument.

[0029] Figures 9A to 9B Example experimental results of stimulus responses are shown. DETAILED DESCRIPTION

[0030] To facilitate an understanding of the present disclosure, reference will now be made to the following examples, and specific language will be used to describe the following examples. It will be understood, however, that no limitation of the scope of the present disclosure is thereby intended, and that such alternatives and further modifications of the subject matter described, and such further applications of the disclosed principles described herein, are contemplated as would normally occur to one skilled in the art to which this disclosure relates.

[0031] The present disclosure relates generally to neuroscience and, more particularly, but not exclusively, to auditory nerve stimulation to produce sound perception in the brain of a subject (such as an animal or human). In one aspect, an implantable electrode array comprising a plurality of spaced-apart microneedles can be implanted into the auditory nerve bundle and stimulate the auditory nerve in response to receiving an electrical signal representative of an observed sound.

[0032] Now refer to Figures 1 to 5 For example, system 10 includes an implantable electrode array 12, an electrical lead 14 electrically coupled to and extending from the implantable electrode array 12, and an auditory signaling device 16 configured to generate one or more electrical signals representative of observed sounds. System 10 also includes an interposer 18 configured to electrically couple the implantable electrode array 12 and the auditory signaling device 16 in an arrangement in which the one or more electrical signals generated by the auditory signaling device 16 can be transmitted to the implantable electrode array 12 via the electrical lead 14. Thus, the auditory signaling device 16, interposer 18, electrical lead 14, and implantable electrode array 12 are all in electrical communication with one another.

[0033] Figures 2 to 5, further details of the implantable electrode array 12 and electrical leads 14 are shown in . More specifically, the implantable electrode array 12 includes a base portion 20 extending between a first end 22 and an opposite second end 24. The base portion 20 includes a plurality of microneedles 26 extending therefrom. Generally speaking, the microneedles 26 can be configured to be positioned in a nerve or nerve bundle, such as the auditory nerve or auditory nerve bundle. In the illustrated form, the implantable electrode array 12 includes 15 microneedles 26, but other variations in the number of microneedles 26 are possible. The microneedles 26 are arranged in a grid defined by five rows, each row including three microneedles 26. Variations in the arrangement and layout of the microneedles 26 are possible and contemplated.

[0034] For example, Figure 4 As best shown in FIG, the microneedles 26 in each row may comprise a length that is different from the length of the microneedles 26 in each of the other rows. More specifically, the microneedles 26a closest to the first end 22 of the base portion 20 may have the shortest length, and the length of the microneedles 26 may increase within each row in the direction of the second end 24. For example, microneedles 26b are taller than microneedles 26a, microneedles 26c are taller than microneedles 26b, microneedles 26d are taller than microneedles 26c, and microneedles 26e are taller than microneedles 26d. In this arrangement, a plane extending along the tips of the microneedles 26 extends transversely to a plane extending between the first end 22 and the second end 24 of the base portion 20.

[0035] In some alternative embodiments, the microneedles 26 include anchoring handles or microneedles. Such anchoring handles can be sized similarly (or identically) to the longest handles in the implantable electrode array 12. Additionally, the anchoring handles can be positioned in opposite rows relative to the row of longest handles. In other words, the anchoring handles can be positioned at the opposite end of the implantable electrode array 12 from the longest handles. Thus, in Figure 4 In an alternative example, if the length of microneedle 26a is sized to match that of microneedle 26e (the longest shank), then microneedle 26a would be the anchoring shank.

[0036] In these and other examples, the microneedle 26 (e.g., electrode shank) can include a variety of different lengths. In at least some examples, the shank length is in the range of about 0.1 mm to about 1.2 mm, thereby being able to extend through the entire cross-sectional area of ​​the auditory nerve for stimulation. In a particular embodiment, the shank length is about 0.9 mm (e.g., when averaged). As used herein, the term "about" with respect to shank length should be interpreted as + / - (plus or minus) 10% of the value. Other examples within the scope of the present disclosure may include different shank lengths.

[0037] In some configurations, one or more stalks in the larger stalk configuration can be deactivated to ensure that the nerve is fully spanned by the implantable electrode array 12. For example, the outer two shortest stalks can be deactivated (leaving the middle shortest stalk in the row active). Additionally or alternatively, one of the longest outer stalks can also be deactivated. Thus, for the example 3x5 pin configuration, 12 or 13 of the pins can be active, and the remaining pins can be deactivated (e.g., for successful and reliable implantation and signal transmission). In some cases, this approach may be more advantageous than a smaller stalk configuration in which all electrodes remain active (e.g., because one or more of the shorter stalks may not be positioned deep enough, one or more of the longer stalks may be positioned too close to the opposing nerve surface, etc.).

[0038] As described above, the implantable electrode array 12 may also include various configurations of microneedles 26. For example, in some embodiments, the microneedles 26 include a 3x5 arrangement of microneedles 26 (e.g., three rows by five columns, or 15 pins). As another example, the microneedles 26 include a 3x4 arrangement of microneedles 26 (e.g., three rows by four columns, or 12 pins). Furthermore, in other examples, the microneedles 26 include a 6x9 arrangement of microneedles 26 (e.g., six rows by nine columns, or 54 pins). Furthermore, in some examples, the microneedles 26 include a 6x10 arrangement of microneedles 26 (e.g., six rows by 10 columns, or 60 pins).

[0039] In these or other embodiments, the microneedles 26 can have various spacings or pitches between each microneedle. For example, a 3x5 arrangement of microneedles 26 can include an electrode pitch of 400 μm. As another example, a 6x9 or 6x10 arrangement of microneedles 26 can include an electrode pitch of 200 μm.

[0040] In some embodiments, the microneedles 26 of the implantable electrode array 12 can be positioned along the nerve based on the location and / or direction of the nerve. For example, in some embodiments, the longest shank of the microneedle 26 can be positioned closer to the cochlear side of the auditory nerve, and the shortest shank of the microneedle 26 can be positioned closer to the brainstem side of the auditory nerve. In certain embodiments, this exemplary configuration allows the electrical lead 14 to protrude away from the shorter shank of the implantable electrode array 12 and toward a bone recess (e.g., for anchoring the electrical lead 14).

[0041] In one form, the implantable electrode array 12 can be formed from a wafer including a wafer surface that has been shaped to correspond to a plane extending along the tips of the microneedles 26. A plurality of grooves can be cut in the wafer to form a plurality of posts having tops aligned with the plane extending along the tips of the microneedles 26. The posts can be rounded and pointed by etching to form the microneedles 26. Further details regarding the formation of the implantable electrode array 12 can be found in U.S. Patents Nos. 8,865,288, 8,886,279, 8,359,083, 7,777,956, and 7,951,300, the contents of which are incorporated herein by reference in their entirety. The implantable electrode array 12 can include features similar to or otherwise configured to be substantially similar or identical to the electrode arrays disclosed in one or more of these patents.

[0042] For example, as in Figure 2 As best seen in FIG, the manipulation feature 28 is disposed on the first end 22 of the base portion 20. More specifically, the manipulation feature 28 can be in the form of an elongated fin that extends from the first end 22 of the base portion 20 and transverse to a plane extending between the first end 22 of the base portion 20 and the second end 24 of the base portion 20. The manipulation feature 28 can be used, for example, to assist in manipulating and positioning the implantable electrode array 12 during implantation of the implantable electrode array 12. For example, the manipulation feature 28 can be used to manipulate the implantable electrode array 12 through bony structures (e.g., the mastoid) and position it at a precise location on the auditory nerve (or nerve bundle). The manipulation feature 28 can also provide a way to move the implantable electrode array 12 to certain locations and through certain structures without damaging the implantable electrode array 12 (e.g., damaging the stem).

[0043] Without intending to be limited to any particular configuration, in one form, the base portion 20 and the microneedles 26 can be formed from a material comprising silicon, which is covered in whole or in part by an iridium oxide coating and / or a parylene-C coating. Additionally, a portion of the implantable electrode array 12 can include a silicone potting deposited thereon, and the manipulation features 28 can be formed from platinum. However, it should be understood that one or more different materials can be employed in addition to or in lieu of the materials identified herein.

[0044] As described above, the electrical lead 14 is electrically coupled to and extends from the implantable electrode array 12. The electrical lead 14 includes a plurality of wires, and one or more of these wires can be individually and electrically coupled to a corresponding one of the plurality of microneedles 26. In one embodiment, for example, the number of microneedles 26 can be greater than the number of wires electrically coupled to the microneedles 26. In this embodiment, not all of the microneedles 26 of the implantable electrode array 12 can be movable. In the illustrated embodiment, the electrical lead 14 includes a first portion 30 and a second portion 32 positioned between the first portion 30 and the implantable electrode array 12. In the first portion 30 of the electrical lead 14, the plurality of wires of the electrical lead 14 can be arranged helically, for example, in a spiral coil. Additionally, in the second portion 32 of the electrical lead 14, the plurality of wires of the electrical lead 14 can be arranged straight or linearly. In both the first portion 30 and the second portion 32, the wires of the electrical lead 14 can be overmolded with silicone.

[0045] In at least some embodiments, second portion 32 includes a bendable portion. As used herein, the term "bendable" refers to a type of wire that exhibits both flexibility and malleability. For example, the bendable portion may include a length of wire in second portion 32 that can be plastically deformed such that second portion 32 retains the deformed shape.

[0046] In some examples, the second portion 32 of the electrical lead 14, extending away from the implantable electrode array 12, includes a bendable portion that provides flexibility to properly align with surrounding bone structures and bone grooves when the implantable electrode array 12 is positioned over the nerve from various angles and in different locations and orientations. The second portion 32 may include a bendable portion of approximately 1 mm to a bendable portion of 20 mm. In a specific example, the second portion 32 includes a bendable portion of approximately 5 mm. This bendable portion can accommodate various anatomical differences in bone structure and nerve orientation by bending into a desired curved shape and maintaining that curved shape, a previously unknown discovery made in multiple cadaver experiments and in vivo intraoperative experiments, including the degree of curvature required in the wire and the length of the wire.

[0047] The flexible portion of the second portion 32 can comprise various gauges or thicknesses (e.g., diameters). For example, the flexible portion of the second portion 32 can comprise a wire having a diameter ranging from 0.25 mm to 2.0 mm. In certain embodiments, the dimensions of the flexible portion of the second portion 32 are substantially similar to those of the auditory nerve (e.g., having a diameter of approximately 1 mm). Furthermore, in at least some embodiments, the dimensions or gauges of the flexible portion of the second portion 32 correspond to a desired degree of flexibility or stiffness. For example, the dimensions or gauges of the flexible portion of the second portion 32 correspond to an adjustment angle between 0 and 180 degrees. Additionally or alternatively, the dimensions or gauges of the flexible portion of the second portion 32 correspond to the amount of force required to manipulate the flexible portion. For example, the dimensions or gauges of the flexible portion of the second portion 32 can be smaller to more sensitively manipulate the direction or angle of the flexible portion of the second portion 32 in response to smaller force loads.

[0048] The bendable portion of the second portion 32 can include a variety of materials. In at least some examples, the bendable portion includes one or more wires formed from a ductile, malleable, non-reactive, and / or biosafe material. For example, the bendable portion includes one or more platinum wires.

[0049] The first portion 30 of the electrical lead 14 also includes a manipulation feature 34, which in the illustrated form is in the form of a handle. More specifically, the manipulation feature 34 generally includes a fin configuration coupled along the length of the first portion 30 of the electrical lead 14. In one form, for example, the manipulation feature 34 can be formed from silicone, although other variations are possible. The manipulation feature 34 can be used, for example, to assist in manipulating and positioning the implantable electrode array 12 and electrical lead 14 during implantation. For example, the manipulation feature 34 can provide improved control when rotating or bending the electrical lead 14 (e.g., using forceps or other surgical instruments).

[0050] As described above, the auditory signal device 16 can be configured to generate one or more electrical signals representing the observed sounds. For example, the auditory signal device 16 can be a subcutaneously implanted stimulator unit that can communicate with a sound processor located outside the body via wired or wireless communication. The auditory signal device 16 can use radio frequency as a wireless communication to the sound processor. The auditory signal device 16 can also be configured to process wired or wireless communications received from a processor outside the body and generate one or more electrical signals representing the observed noises and sounds for communication via the implantable electrode array 12.

[0051] As described above, the system 10 also includes an interposer 18 that is configured to electrically couple the implantable electrode array 12 and the auditory signal device 16 in an arrangement in which one or more electrical signals generated by the auditory signal device 16 can be transmitted to the implantable electrode array 12 via the electrical leads 14. In one form, the auditory signal device 16 can include a plurality of electrical pins 36 through which the electrical signals generated by the auditory signal device 16 can be provided. In this form, the interposer 18 can be configured to engage the electrical pins of the auditory signal device 16. For example, the interposer 18 can be configured to receive and / or engage the electrical pins 36 of the auditory signal device 16, such as Figure 6 As shown, the positioning of the interposer 18 relative to the electrical pins 36 may be at least partially fixed.

[0052] The interposer 18 includes a plurality of contact pads 38, each of which provides a connection or bonding location for a corresponding wire of the electrical lead 14 and a corresponding wire extending to a corresponding one of the plurality of electrical pins 36. As an example, the number of contact pads 38 provided on the interposer 18 can correspond to the number of electrical pins 36 from which electrical signals can be provided to the implantable electrode array 12, although variations are possible. Figure 6 Wire 40 and wire 42 from electrical lead 14 are shown, with wire 42 extending to a respective one of the plurality of electrical pins 36 connected to one of the contact pads 38 .

[0053] In one form, wire 40 (and other wires of electrical leads 14 extending to different corresponding ones of contact pads 38) can be formed from a first material or a combination of first materials, and wire 42 (and other wires extending from different corresponding ones of contact pads 38 to electrical leads 36) can be formed from a second material or a combination of second materials. Furthermore, each of contact pads 38 can be formed from a material that is the same as the first material or one of the materials combined with the first material, or from a material that is the same as the second material or one of the materials combined with the second material. As a non-limiting example, wire 40 can be formed from gold, wire 42 can be formed from a combination of platinum and iridium, and contact pad 38 can be formed from platinum. However, other variations in the materials forming wire 40, wire 42, and contact pad 38 are possible and contemplated. In one form, for example, the wires 40 and 42 may be soldered or otherwise coupled to or integrated into respective contact pads 38 such that the wires 40 and 42 are electrically coupled at the respective contact pads 38. Similarly, the electrical signal provided by the auditory signal device 16 may be provided to the wires of the electrical lead 14 to ultimately produce electrical stimulation through one or more of the microneedles 26 of the implantable electrode array 12.

[0054] In alternative embodiments, the audible signaling device 16 may include an electrical lead extending therefrom and including a plurality of wires. The interposer 18 may include a plurality of contact pads 38, each of which provides a connection location for the wires of the electrical leads 14 and the wires of the electrical leads extending from the audible signaling device 16. These wires and contact pads 38 may be the same or substantially similar to the wires 40 and 42 and contact pads 38 described in the previous paragraphs, although variations are possible. It is also contemplated that in one or more embodiments, the wires of the electrical leads 14 may be electrically coupled directly to the electrical pins 36 of the audible signaling device 16 or to the wires of the electrical leads extending from the audible signaling device 16. In these embodiments, it is contemplated that the interposer 18 may be omitted from the system 10.

[0055] In one embodiment, the interposer 18 can be formed from a ceramic material, but other variations are possible. For example, there are embodiments in which the interposer 18 can be formed from a liquid crystal polymer and include a Ti / Pd interlayer. In these embodiments, when the audible signaling device 16 includes electrical pins 36, the electrical pins 36 can be flattened relative to the interposer 18, and gold ribbon can be used as contact pads for electrical connection between the electrical pins 36 and the wires of the electrical leads 14. In another embodiment, it is contemplated that the interposer 18 can be formed from platinum and include multiple laser-cut features to prevent the introduction of foreign material. In one embodiment, when the interposer 18 is formed from platinum, a Pt / Ir foil can be used for welding or brazing to the electrical pins 36. In yet another embodiment, the interposer 18 can be formed from platinum and aluminum oxide particles.

[0056] Although not previously described, it is also contemplated that an interposer 18, as described herein or otherwise configured, can be fitted between the electrical pins 36 of the audible signal device 16 and accessed from the side for adhesion or gluing to the electrical pins 36. Alternatively, in these embodiments, the interposer 18 can be welded or soldered to the electrical pins 36. Furthermore, as described above, in lieu of an interposer 18, it is also contemplated that the wires of the electrical leads 14 can be directly coupled to one of the electrical pins 36 (if present) or to a corresponding wire of an electrical lead extending from the audible signal device 16. For example, in such an embodiment, it is contemplated that the electrical pins 36 can be flattened to provide a surface with a larger area for coupling the wires of the electrical leads 14. Embodiments are also contemplated in which the wires are glued and / or soldered.

[0057] When interposer 18 electrically couples implantable electrode array 12 and auditory signal device 16, or implantable electrode array 12 and auditory signal device 16 are otherwise electrically coupled, one or more electrical signals generated by auditory signal device 16 can be transmitted to implantable electrode array 12 via electrical leads 14. Thus, one or more of microneedles 26 can apply corresponding electrical stimulation to the auditory nerve / auditory nerve bundle to produce a sound perception corresponding to the sound received and recorded by auditory signal device 16.

[0058] The implantable electrode array 12 may be implanted by any suitable technique (e.g., a retrosigmoid (suboccipital) approach, a translabyrinthine approach, a sublabyrinthine / subcochlear approach, etc.). In one form, for example, the implantable electrode array 12 may be implanted by any suitable technique (e.g., a retrosigmoid (suboccipital) approach, a translabyrinthine approach, a sublabyrinthine / subcochlear approach, etc.). Figure 7 The device or instrument 44 is shown for implantation. The instrument 44 includes an outer sleeve or outer housing 46 and a plunger member 48 that can be positioned and moved within the outer housing 46 to deliver the implantable electrode array 12. The plunger member 48 and the outer housing 46 can be sized relative to each other to control the speed of insertion of the instrument 44. In one form, for example, the length of the plunger member 48 can be increased and the length of the outer housing 46 can be decreased to reduce the speed of insertion of the instrument 44. The speed of insertion can be controlled by a pneumatic control system integrated into the device or instrument 44.

[0059] In one embodiment, the plunger member 48 may include a delivery end 50 having a recess formed therein that is configured to engage the implantable electrode array 12. In one form, for example, one or more drops of saline may be employed to facilitate engagement of the implantable electrode array 12 with the delivery end 50 of the device 44. In one form, the recess may be formed by, for example, Figure 8A However, in another form, the recess may be formed by a recess such as Figure 8B The concave dome 52 shown may be formed by Figure 8C The linear slot 52c shown is formed. Other variations of the recess formed in the delivery tip 50 are possible.

[0060] The electrical leads 14 of the implantable electrode array 12 can be implanted in at least one bone groove created during surgery that can retain the electrical leads 14. Such bone grooves can help maintain the position of the electrical leads 14 and help provide strain relief. For illustration, a bone groove with a diameter of less than one millimeter and a depth just over one millimeter can allow the electrical leads 14 to be inserted therein. These or other appropriately sized bone grooves can be formed using commercially available 0.5-0.8 mm diamond burrs. Moderate pressure can also help retain the electrical leads 14 within the bone grooves.

[0061] In one example of a bone groove embodiment, two grooves can be formed within the mastoid cavity. For example, a first groove can be positioned within the first 1.5 cm of the electrical lead 14 (e.g., at the first portion 30 of the helical bundle) and, therefore, between about 0.5 cm and about 2 cm from the insertion site. In a translabyrinthine approach, this first groove can be achieved posterior to the bone and / or posterior to the IAC (internal auditory canal) below the jugular bulb. In a retrosigmoid approach, the first groove can be formed (e.g., drilled) in the petrous bone surface. A second bone groove can be formed in a more variable position based on the mastoid anatomy (or other bone anatomy variations) and located closer to the insertion site of the implantable electrode array 12. In some embodiments, the second bone groove can be placed closer to the cortex, posterior to the temporal line or the edge of the mastoid cortex.

[0062] In at least some examples, a bone groove can be formed relative to the implant body that is fixed or positioned beneath the temporalis muscle and periosteum. For example, a groove can be formed from the implant bed to the mastoid process. In some embodiments, the groove can help prevent the electrical lead 14 or the implantable electrode array 12 from being exposed to any sharp edges and / or can provide stability when manipulating the electrical lead 14 or placing the implantable electrode array 12 in place.

[0063] Other stabilization methods are also contemplated herein. For example, a hemostatic matrix (e.g., Surgicel® absorbable hemostatic material) can be placed over the implantable electrode array 12 to provide additional surface tension. As another example, strips of abdominal fat can be tightly packed over the implantable electrode array 12 to fill the mastoid cavity. In yet another example, the implantable electrode array 12 can be tethered in place via a tethering material, such as a mesh strip (e.g., polyester Dacron® mesh). For example, the tethering material can be mounted on the back of the implantable electrode array 12 and wrapped around one or more nerves (e.g., the auditory nerve) to maintain the position of the implantable electrode array 12.

[0064] In one embodiment, a method may include accessing an auditory nerve or auditory nerve bundle and implanting an implantable electrode array 12 in the auditory nerve or auditory nerve bundle. Electrical leads 14 may extend from the implantable electrode array 12 to an auditory signal device 16 located at a separate, discrete location on a person's body. In one embodiment, the electrical leads 14 extending between the implantable electrode array 12 and the auditory signal device 16 may be placed beneath the person's skin. The auditory signal device 16 may be a subcutaneously implanted stimulator unit that can communicate wired or wirelessly with a sound processor located outside the body. The auditory signal device 16 may use radio frequency for wireless communication with the sound processor. The auditory signal device 16 may also be configured to process wired or wireless communications received from a processor located outside the body and generate one or more electrical signals, via the implantable electrode array 12, representing the received wired or wireless communications. The one or more electrical signals may be transmitted to the implantable electrode array 12 and applied to the auditory nerve or auditory nerve bundle via one or more of the microneedles 26. As a result, the auditory nerve or auditory nerve bundles can be stimulated in a manner intended to create a sound perception in the person's brain that corresponds to the observed sound.

[0065] The auditory signal device 16 can be used to perform tonal topography mapping of the auditory nerve by stimulating the auditory nerve at various widths and depths using one or more of the microneedles 26, thereby activating hearing across a wide frequency range. The auditory signal device 16 can also be used to perform electron beam steering and / or current steering between the one or more of the microneedles 26. Electron beam steering and / or current steering can achieve three-dimensional stimulation of the auditory nerve to create a higher-fidelity perception of sound, whereas conventional cochlear implants are only capable of linear or two-dimensional stimulation.

[0066] The system 10 may include a sound processor configured to implement a vocoded stimulation strategy. The vocoded stimulation strategy may include a signal processing module, a stimulation module, and a pulse shape module.

[0067] The signal processing module of the sound coding stimulation strategy can use a filter bank configured to decompose the acoustic signal into one or more sub-band signals. The filter bank can be implemented by a fast Fourier transform, a digital filter, or other types of spectral or temporal filters. For example, the sound coding stimulation strategy can decompose the acoustic signal into one or more component frequencies of the acoustic signal. The signal processing module of the sound coding stimulation strategy can decompose the acoustic signal into any number of sub-bands, and each sub-band can be delivered to the auditory nerve via the same or a reduced number of independent channels of the microneedles 26. In another example, the signal processing module of the sound coding stimulation strategy can decompose the acoustic signal into 12 possible sub-band frequencies, each of which can be independently delivered to the auditory nerve via an independent channel of the microneedles 26, or delivered to the auditory nerve in some identified arrangement on the auditory nerve based on psychophysical testing and evaluation of the induced perception caused by electrical stimulation of each microneedle 26. In an alternative example, the signal processing module of the vocoding stimulation strategy may decompose the acoustic signal into one or more high-definition sub-bands, where a subset of the high-definition sub-bands may be selectively delivered to the auditory nerve via the system 10 .

[0068] The stimulation module of the sound encoding stimulation strategy can be configured to encode the one or more sub-band signals into discrete electrical pulses that can be delivered to the auditory nerve by the system 10 via the microneedles 26, wherein each sub-band can be delivered by a separate microneedle 26. As described above, the microneedles 26 can be configured to have varying lengths and, therefore, varying nerve penetration depths. The penetration depths of the microneedles 26 can provide access to different nerves in the auditory nerve bundle, wherein the depth of each nerve in the auditory nerve bundle can be related to the sensation of a specific sound frequency.

[0069] In one embodiment, the one or more sub-band signals can be categorized by their frequency for delivery by the microneedles 26 to a specific depth in the auditory nerve corresponding to the sensation of the sound frequency. In one example, a sub-band of the one or more sub-band signals can be a high-frequency sub-band, while another sub-band of the one or more sub-band signals can be a low-frequency sub-band. In one embodiment, the high-frequency sub-band can be delivered to the auditory nerve by the system 10 via the microneedles 26 using one of the microneedles that penetrates the auditory nerve at a shallow depth, which is a depth that can be associated with the sensation of high-frequency sounds. In another embodiment, the low-frequency sub-band can be delivered to the auditory nerve by the system 10 via the microneedles 26 using one of the microneedles that penetrates the auditory nerve at a deep depth, which is a depth that can be associated with the sensation of low-frequency sounds.

[0070] The stimulation module of the vocoding stimulation strategy can be configured to deliver a perception of temporal pitch to the auditory nerve via the system 10. For example, the stimulation module of the vocoding stimulation strategy can be configured to provide a stimulation protocol corresponding to a desired temporal pitch and / or loudness of an acoustic signal to the auditory nerve via the system 10. In one example, the perception of temporal pitch can be generated by providing electrical stimulation pulses at multiple zero crossings of a low-frequency subband signal of a filter bank. Each channel of the microneedles 26 of the system 10 can be configured to deliver a different stimulation protocol to the auditory nerve for each channel of the microneedles 26 to accommodate the different loudness or pitch of each subband of the acoustic signal.

[0071] The stimulation module of the sound coding stimulation strategy can be configured to stimulate using one or more stimulation coding strategies, including monopolar virtual current steering, bipolar stimulation, tripolar stimulation, or other focused and non-focused stimulation protocols. Each of the one or more stimulation coding strategies can be suitable for a specific stimulation, such as stimulation intended to produce the sensation of low-intensity sound in the auditory nerve. For example, a stimulation coding strategy configured for a focused stimulation protocol may be more suitable for delivering low-intensity sounds, while a non-focused stimulation protocol may be more suitable for delivering high-intensity sounds.

[0072] The pulse shape module of the vocoded stimulation strategy can be configured to ensure patient safety during the application of electrical stimulation by the system 10. The two polarities of the stimulation pulse (anodic and cathodic) can depolarize nerve fibers and generate action potentials in the auditory nerve. The pulse shape module can be configured to deliver symmetrical, asymmetrical pseudo-monophasic, triphasic, or other multiphasic stimulation. The pulse shape module of the vocoded stimulation strategy can also be configured to deliver a phased array similar to stimulation. In such an example, a transimpedance matrix (TIM) is used to estimate the voltage distribution caused by each channel of the microneedle 26. In another example, the pulse shape module of the vocoded stimulation strategy can include delivering an inverse signal of the measured simulated neural response, which can include one or more stimulation peaks to reduce the impact of side excitation peaks or multiple excitation peaks. The system 10 can then deliver a stimulation via the microneedle that is the inverse signal of the TIM or neural response to produce a voltage distribution that is as focused as possible.

[0073] The implant's stimulation pulses are generated at a fixed repetition rate and delivered to the electrodes in a staggered manner. Previous observations in subjects receiving an electrical auditory implant consisting of penetrating electrodes in the inferior colliculus (midbrain), known as an auditory midbrain implant (AMI), have shown that stimulating the same electrode at a higher rate results in a larger refractory period. This issue can be addressed by increasing the interpulse interval (the gap between pulses) of stimulation, which is equivalent to reducing the repetition rate. However, this necessary reduction does not allow for integration to achieve sufficient loudness perception and modulation of the original signal. A novel stimulation module involves delivering signals from the same frequency band to multiple electrodes at a higher overall rate, thereby achieving sufficient loudness without incurring a refractory period. This was originally observed in animal models, where higher activity (equivalent to higher loudness) was measured in the auditory cortex. This presupposes that multiple stimulating electrodes elicit similar tones of similar pitch. This implies that the stimulated neurons are coherent and located in the same isofrequency layer. Each electrode will be stimulated at a lower rate, but the overall stimulation rate will be higher than when stimulating a single electrode. This effect was demonstrated by measuring the applied current required to achieve equal loudness across multiple electrodes compared to a single electrode. It is possible that the neural patterns induced by ANI stimulation, which is a more central prosthesis than CI and therefore more similar to an auditory brainstem implant (ABI) or auditory midbrain implant, exhibit similar integration properties. In this case, the described stimulation pattern, based on distributing pulses across different electrodes to deliver the same spectral content, could improve integration properties.

[0074] A typical CI device can present a constant pulse rate to a given electrode at a specific frequency region of the cochlea, where the pulse train is amplitude modulated by the envelope of a bandpass-filtered signal for the corresponding frequency range of that cochlear region. The modulation can have varying modulation depths and modulation frequency ranges based on the extracted envelope of the filtered signal for that corresponding frequency channel. As the amplitude modulation increases, a greater number of nearby neurons are activated, where these neurons correspond to similar or nearby frequencies encoded in the cochlea. Thus, while the frequency or pitch perception remains close to the stimulation frequency region of the cochlea, the perception becomes louder.

[0075] The auditory nerve has nerve fibers that respond to different frequency perceptions, and these fibers can twist along the way from the cochlea to the brainstem. Consequently, nearby nerve fibers may not respond to similar frequencies, but rather have separate frequency perceptions or frequency and pitch perceptions that jump to distant perceptions of adjacent activated nerve fibers. We have observed such stimulation patterns in our animal studies, such as guinea pigs (see Figure 9A and Figure 9B ), experiments with cats and monkeys.

[0076] Compared to the amplitude modulation stimulation methods implemented in CI devices, the present disclosure includes stimulation methods that implement position modulation stimulation. In other words, rather than increasing the current on a given electrode, the stimulation methods of the present disclosure include different electrode sites that are activated in a manner corresponding to similar or nearby frequencies to activate more neurons. This positional stimulation can be fine-tuned or optimized by adding more (or changing) activation sites rather than increasing the current on a single electrode. In addition, the electrodes can be mapped to corresponding frequencies or pitch perceptions during the fitting process for each electrode being stimulated. In some embodiments, the electrodes are pitch-sorted using pitch scaling or pitch-sorting psychophysical methods.

[0077] In another stimulation strategy method of the present disclosure, a combination of such position modulation and amplitude modulation stimulation strategies can be used. In the example of such position amplitude modulation stimulation, the current of a given electrode can be increased (or decreased) to obtain a certain range of activated neurons. In addition, other electrodes can be activated corresponding to similar frequencies. These stimulation patterns will be driven by envelope or bandpass filter information extracted from the original sound signal. However, instead of using it to amplitude modulate the pulse train of each electrode, stimulation of different electrodes is added to produce a louder perception of similar frequencies or pitches. In yet another example, a varying pulse rate can be used additionally (or alternatively) for each electrode to increase or modulate the loudness of similar frequencies or pitch perceptions. Therefore, in some embodiments, the implantable electrode array of the present disclosure can be used to perform a combination of rate modulation, position modulation and / or amplitude modulation on mapping electrodes across the auditory nerve.

[0078] Now about Figures 9A to 9B Experimental data supporting one or more of the aforementioned stimulation strategies are discussed. These figures illustrate patterns of neural activity in the central nucleus of the inferior colliculus (ICC) in response to electrical stimulation at various sites of an electrode array implanted in the auditory nerve. The multichannel electrodes used for recording were aligned along the tonotopic axis of the ICC. Each recording channel corresponded to a different frequency region of the ICC, as determined by generating an acoustic tuning curve. For each stimulation site, a stimulus-response map (SRM) was generated by presenting a range of current levels (Y-axis) and recording activity across the frequency channels (X-axis). The color bar of each SRM indicates the number of spikes detected after stimulus delivery. Brighter (yellow) areas on the SRM indicate a higher number of spikes detected, while darker (blue) areas indicate a lower number of spikes.

[0079] From the tip to the base of the stimulation array, Figure 9A Placement A in shows a gradual shift from low-frequency activation (e.g., sites 3 and 4) to high-frequency activation (e.g., site 14). In contrast, Figure 9BPosition B in Figure 2 shows a discontinuous shift from low-frequency to high-frequency activation. This is particularly evident for sites 5 and 7, which show strong activation at very low and very high frequencies, but little activation at intermediate frequencies. This activation pattern is likely due to the placement of the stimulation sites in an area of ​​the auditory nerve where low-frequency and high-frequency fiber groups run close together.

[0080] These and / or other embodiments of the present disclosure can be found in Appendix AH. In particular, Appendix AH includes NIH (National Institutes of Health) Milestone Reports, each of which is expressly incorporated herein by reference in its entirety.

[0081] In one embodiment, a system includes an implantable electrode array comprising a plurality of spaced-apart microneedles. The system also includes a first electrical lead electrically coupled to and extending from the implantable electrode array; and an auditory signaling device configured to generate one or more electrical signals representative of observed sounds. An interposer is configured to electrically couple the implantable electrode array and the auditory signaling device in an arrangement wherein the one or more electrical signals generated by the auditory signaling device can be transmitted to the implantable electrode array via the first electrical lead. In an alternative form, it is contemplated that the first electrical lead can be electrically coupled directly to the auditory signaling device without the interposer.

[0082] In one aspect, the interposer is formed from a ceramic material.

[0083] In another aspect, the audio signal device includes a plurality of electrical pins, and the interposer is configured to receive the plurality of electrical pins.

[0084] In one form of this aspect, the interposer includes a plurality of contact pads, and each of the plurality of contact pads provides a coupling location for a corresponding wire of the first electrical lead and a corresponding electrical pin wire extending to a corresponding one of the plurality of electrical pins.

[0085] In another form of this aspect, the respective wires of the electrical leads are formed from a first material or a first combination of materials, and the respective electrical pin wires are formed from a second material or a second combination of materials.

[0086] In yet another form of this aspect, each of the plurality of contact pads is formed of a material that is the same as the first material or one of the materials combined with the first material, or is formed of a material that is the same as the second material or one of the materials combined with the second material.

[0087] In yet another form of this aspect, the respective wires of the electrical leads are formed of gold, the respective electrical pin wires are formed of a combination of platinum and iridium, and the contact pads are formed of platinum.

[0088] In another aspect, the audible signaling device includes a second electrical lead extending therefrom, and the interposer includes a plurality of contact pads, each contact pad providing a coupling location for a corresponding wire of the first electrical lead and a corresponding wire of the second electrical lead.

[0089] In yet another aspect, the first electrical lead comprises a plurality of wires, and one or more wires of the plurality of wires are individually and electrically coupled to a corresponding one of the plurality of microneedles.

[0090] In yet another aspect, a first electrical lead comprises a plurality of wires, a first portion and a second portion positioned between the first portion and the implantable electrode array, wherein the plurality of wires are helically arranged in the first portion and the plurality of wires are linearly arranged in the second portion.

[0091] In another aspect, an implantable electrode array extends between a first end and an opposite second end and includes a first manipulation feature defined by an elongated pin extending laterally from the first end.

[0092] In one form of this aspect, the first electrical lead further includes a second handling feature defined by a handle extending from and connected to the first electrical lead at discrete locations.

[0093] In one aspect, the first electrical lead includes a handling feature defined by the handle, the handling feature extending from and connected to the first electrical lead at discrete locations.

[0094] In one aspect, the plurality of microneedles of the implantable electrode array are arranged in a grid comprising a plurality of rows, and the length of each microneedle in a respective row is different from the length of each microneedle in a different row.

[0095] In another embodiment, a device includes an implantable electrode array comprising a plurality of spaced-apart microneedles; an electrical lead electrically coupled to and extending from the implantable electrode array and comprising a plurality of wires; and an interposer comprising a plurality of contact pads. One or more wires of the plurality of wires of the electrical lead are individually and electrically coupled to corresponding contact pads of the plurality of contact pads.

[0096] In one aspect, the interposer is formed from a ceramic material.

[0097] In another aspect, the plurality of wires of the electrical leads include a first material or a first combination of materials, and the plurality of contact pads include a second material or a second combination of materials.

[0098] In one form of this aspect, one or more of the plurality of wires of the electrical leads comprises gold, and the plurality of contact pads comprises platinum.

[0099] In another aspect, one or more wires of the plurality of wires are individually and electrically coupled to a corresponding one of the plurality of microneedles.

[0100] In another aspect, the electrical lead includes a first portion and a second portion positioned between the first portion and the implantable electrode array and wherein the plurality of wires are helically arranged in the first portion and linearly arranged in the second portion.

[0101] In yet another aspect, an implantable electrode array extends between a first end and an opposite second end and includes a first manipulation feature defined by an elongated pin extending laterally from the first end.

[0102] In one form of this aspect, the electrical lead further includes a second manipulation feature defined by a handle extending from and connected to the electrical lead at discrete locations.

[0103] In yet another aspect, the electrical leads include a handling feature defined by the handle, the handling feature extending from and connected to the first electrical lead at discrete locations.

[0104] In one other aspect, the plurality of microneedles of the implantable electrode array are arranged in a grid comprising a plurality of rows, and the length of each microneedle in a respective row is different from the length of each microneedle in a different row.

[0105] In one embodiment, a method includes providing a system comprising:

[0106] an implantable electrode array comprising a plurality of spaced-apart microneedles;

[0107] a first electrical lead electrically coupled to and extending from the implantable electrode array; and

[0108] An auditory signaling device is configured to generate one or more electrical signals representative of the observed sounds.

[0109] An interposer is configured to electrically couple the implantable electrode array and the auditory signal device in an arrangement wherein one or more electrical signals generated by the auditory signal device can be transmitted to the implantable electrode array via the first electrical lead. The method also includes implanting the implantable electrode array into an auditory nerve of a person, and positioning the auditory signal device at a discrete location on the person's body spaced apart from the implantable electrode array, the auditory signal device being in electrical communication with the implantable electrode array.

[0110] In one aspect, the method further includes providing an apparatus for implanting an implantable electrode array. The apparatus includes an outer housing and a plunger member positionable and movable within the outer housing. The plunger member includes a delivery end having a recess formed therein and configured to engage the implantable electrode array.

[0111] In one form of this aspect, the recess is defined by a concave slot, a concave dome, or a linear slot.

[0112] In one aspect, an implantable electrode array is implanted with the device.

[0113] It should be understood that the subject matter disclosed herein can be used in a variety of different settings. For example, but not limited to, the subject matter disclosed herein can be deployed to assist subjects experiencing hearing loss. Additionally or alternatively, the subject matter disclosed herein can be used in research or other scenarios aimed at determining the effect of electrical stimulation of the auditory nerve or auditory nerve bundles on the perception of sound.

[0114] The present disclosure may be embodied in other specific forms without departing from the spirit or essential characteristics of the present disclosure. The described embodiments are to be considered in all respects as illustrative only and not restrictive. The scope of the present disclosure is therefore indicated by the appended claims rather than by the foregoing description. All variations that come within the meaning and range of equivalents of the claims are intended to be included within their scope.

[0115] As used in this specification, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, the term "member" is intended to mean a single member or a combination of members, and "material" is intended to mean one or more materials or a combination thereof.

[0116] When used in conjunction with "cylindrical," "linear," and / or other geometric relationships, the term "substantially" is intended to indicate that the structure so defined is nominally cylindrical, linear, etc. As an example, a portion of a support member described as "substantially linear" is intended to convey that while linearity of the portion is desired, some nonlinearity may occur in the "substantially linear" portion. Such nonlinearity may be caused by manufacturing tolerances or other practical considerations (e.g., pressure or forces applied to the support member). Thus, a geometric configuration modified by the term "substantially" includes such geometric characteristics within a tolerance of plus or minus 5% of the geometric configuration. For example, a "substantially linear" portion is a portion of an axis or centerline that is defined within plus or minus 5% of linearity.

[0117] As used herein, the terms "group" and "plurality" can refer to a plurality of features or a singular feature having a plurality of parts. For example, when referring to a group of electrodes, the group of electrodes can be considered to be one electrode having a plurality of parts, or the group of electrodes can be considered to be a plurality of different electrodes. Additionally, for example, when referring to a plurality of electrochemical cells, the plurality of electrochemical cells can be considered to be a plurality of different electrochemical cells or one electrochemical cell having a plurality of parts. Thus, a group of parts or a plurality of parts can include a plurality of parts that are continuous or discontinuous with each other. A plurality of particles or a plurality of materials can also be made from a plurality of items that are produced separately and later combined together (e.g., by mixing, adhesives, or any suitable method).

Claims

1. An auditory nerve stimulation system comprising: implantable electrode arrays; a first electrical lead electrically coupled to and extending from the implantable electrode array; an auditory signaling device configured to generate one or more electrical signals representative of communications received from an external processor; as well as An interposer is electrically coupled to the first electrical lead and the auditory signaling device to enable one or more electrical signals generated by the auditory signaling device to be transmitted through the first electrical lead to the implantable electrode array.

2. The auditory nerve stimulation system according to claim 1, wherein The interposer is formed of a ceramic material.

3. The auditory nerve stimulation system according to claim 1, wherein The audible signaling device includes electrical pins, and the interposer is configured to receive and electrically couple with the electrical pins.

4. The auditory nerve stimulation system according to claim 3, wherein The interposer includes contact pads, and each of the contact pads provides a coupling location for a corresponding wire of the first electrical lead and a corresponding electrical pin wire extending to a corresponding one of the electrical pins.

5. The auditory nerve stimulation system according to claim 4, wherein The respective wires of the first electrical leads are formed from a first material or a first combination of materials, and the respective electrical pin wires are formed from a second material or a second combination of materials.

6. The auditory nerve stimulation system according to claim 5, wherein Each of the contact pads is formed of a material that is the same as the first material or a material in combination with the first material, or is formed of a material that is the same as the second material or a material in combination with the second material.

7. The auditory nerve stimulation system according to claim 6, wherein The respective wires of the first electrical leads are formed of gold, the respective electrical pin wires are formed of a combination of platinum and iridium, and the contact pads are formed of platinum.

8. The auditory nerve stimulation system according to claim 1, wherein The audible signaling device includes a second electrical lead extending therefrom, and the interposer includes contact pads, each contact pad providing a coupling location for a corresponding wire of the first electrical lead and a corresponding wire of the second electrical lead.

9. The auditory nerve stimulation system according to claim 1, wherein The first electrical lead includes a plurality of wires, and one or more wires of the plurality of wires are individually and electrically coupled to a corresponding one of the plurality of microneedles.

10. The auditory nerve stimulation system according to claim 1, wherein The first electrical lead comprises a plurality of wires, a first portion, and a second portion, the second portion being positioned between the first portion and the implantable electrode array, and wherein in the first portion, the plurality of wires are helically arranged, and in the second portion, the plurality of wires are linearly arranged.

11. The auditory nerve stimulation system according to claim 10, wherein: The second portion includes a bendable portion.

12. The auditory nerve stimulation system according to claim 11, wherein The bendable portion includes one or more platinum wires.

13. The auditory nerve stimulation system according to claim 1, wherein The implantable electrode array extends between a first end and an opposite second end and includes a first manipulation feature defined by an elongated pin extending laterally from the first end.

14. The auditory nerve stimulation system according to claim 13, wherein The first electrical lead also includes a second handling feature defined by a handle extending from and connected to the first electrical lead at discrete locations.

15. The auditory nerve stimulation system according to claim 1, wherein The electrode array comprises a plurality of microneedles, wherein the plurality of microneedles of the implantable electrode array are arranged in a grid comprising a plurality of rows, and wherein a length of each microneedle in a respective row is different from a length of each microneedle in a different row.

16. The auditory nerve stimulation system according to claim 15, wherein The length of each microneedle of the plurality of microneedles is in a range from about 0.1 mm to about 1.2 mm.

17. An auditory nerve stimulation device comprising: an implantable electrode array comprising a plurality of spaced-apart microneedles; an electrical lead electrically coupled to and extending from the implantable electrode array and comprising a plurality of wires; as well as an interposer, the interposer comprising contact pads; wherein one or more of the plurality of wires of the electrical leads are individually and electrically coupled to corresponding ones of the contact pads.

18. The auditory nerve stimulation apparatus according to claim 17, wherein The interposer is formed of a ceramic material.

19. The auditory nerve stimulation apparatus according to claim 17, wherein The plurality of wires of the electrical leads include a first material or a first combination of materials, and the plurality of contact pads include a second material or a second combination of materials.

20. The auditory nerve stimulation apparatus according to claim 19, wherein One or more of the plurality of wires of the electrical leads include gold, and the plurality of contact pads include platinum.

21. The auditory nerve stimulation apparatus according to claim 17, wherein One or more wires of the plurality of wires are individually and electrically coupled to a corresponding one of the plurality of microneedles.

22. The auditory nerve stimulation apparatus according to claim 17, wherein The electrical lead includes a first portion and a second portion, the second portion being positioned between the first portion and the implantable electrode array, and wherein, in the first portion, the plurality of wires are helically arranged, and in the second portion, the plurality of wires are linearly arranged.

23. The auditory nerve stimulation apparatus according to claim 17, wherein The implantable electrode array extends between a first end and an opposite second end and includes a first manipulation feature defined by an elongated pin extending laterally from the first end.

24. The auditory nerve stimulation apparatus according to claim 23, wherein The electrical lead also includes a second manipulation feature defined by a handle extending from and connected to the electrical lead at discrete locations.

25. The auditory nerve stimulation apparatus according to claim 17, wherein The plurality of microneedles of the implantable electrode array are arranged in a grid comprising a plurality of rows, and a length of each microneedle in a corresponding row is different from a length of each microneedle in a different row.

26. A method comprising: Providing a system according to claim 1; implanting the implantable electrode array into a human auditory nerve; as well as The auditory signaling device is positioned at a discrete location on the body that is spaced apart from the implantable electrode array and is in electrical communication with the implantable electrode array.

27. The method of claim 26, further comprising providing a device for implanting the implantable electrode array, the device comprising an outer shell and a plunger member, the plunger member being positionable and movable within the outer shell, and the plunger member comprising a delivery end having a recess formed therein, the recess being configured to engage with the implantable electrode array.

28. The method according to claim 27, wherein The recess is defined by a concave slot, a concave dome, or a linear slot.

29. The method according to claim 27, wherein The implantable electrode array is implanted with the device.

30. The method of claim 26, wherein: The implantable electrode array comprises: a first set of electrode shanks; and The electrode handles of the second group are shorter than the electrode handles of the first group.

31. The method according to claim 30, wherein: The implantable electrode array is oriented such that the electrode shafts of the first set are positioned closer to the human cochlea than the electrode shafts of the second set; and The implantable electrode array is oriented such that the electrode shafts of the second set are closer to the person's brainstem than the electrode shafts of the first set.

32. The method of claim 26, further comprising: forming at least one bone groove within a bone structure of a person; as well as Electrical leads coupled to the implantable electrode array are positioned within the bone structure.

33. A method comprising: A system for stimulating neural tissue is provided, the system comprising: implantable electrode arrays; a first electrical lead electrically coupled to and extending from the implantable electrode array; an auditory signaling device configured to generate one or more electrical signals representative of communications received from an external processor; and an interposer configured to electrically couple the implantable electrode array and the auditory signal device in an arrangement in which one or more electrical signals generated by the auditory signal device can be transmitted to the implantable electrode array through the first electrical lead; and Positional amplitude stimulation signals are transmitted from the system to the neural tissue at a plurality of electrode sites corresponding to the implantable electrode array.

34. The method according to claim 33, wherein The implantable electrode array includes electrodes arranged in a sequence of pitches.

35. The method of claim 33, wherein: The transmission position amplitude stimulus signal includes: transmitting a first signal at a first frequency via a first electrode of the implantable electrode array; and A second signal is transmitted via a second electrode of the implantable electrode array at a second frequency that is different from the first frequency.

36. The method of claim 33, further comprising: At least one of an amplitude modulated stimulation signal or a rate modulated signal is transmitted from the system to the neural tissue at the plurality of electrode sites corresponding to the implantable electrode array.

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