COCHLEAR IMPLANTS HAVING MRI-COMPATIBLE MAGNET APPARATUS AND ASSOCIATED SYSTEMS AND METHODS

A system including a cochlear implant with a cochlear lead including a plurality of electrodes, an antenna, a stimulation processor operably connected to the antenna and to the cochlear lead, and a magnet apparatus, adjacent to the antenna, including a case defining a central axis, a frame within the case and rotatable relative to the case about the central axis of the case, and only two elongate diametrically magnetized magnets that are located in the frame, that are separated from one another by a fixed non-zero distance, that each define a longitudinal axis and a N-S direction, and that are rotatable about the longitudinal axis relative to the frame, and an external device including an axially magnetized disk-shaped positioning magnet and an antenna adjacent to the axially magnetized disk-shaped positioning magnet.

BACKGROUND

The present disclosure relates generally to implantable cochlear stimulation (or “ICS”) systems.

2. Description of the Related Art

ICS systems are used to help the profoundly deaf perceive a sensation of sound by directly exciting the intact auditory nerve with controlled impulses of electrical current. Ambient sound pressure waves are picked up by an externally worn microphone and converted to electrical signals. The electrical signals, in turn, are processed by a sound processor, converted to a pulse sequence having varying pulse widths, rates and/or amplitudes, and transmitted to an implanted receiver circuit of the ICS system. The implanted receiver circuit is connected to an implantable electrode array that has been inserted into the cochlea of the inner ear, and electrical stimulation current is applied to varying electrode combinations to create a perception of sound. The electrode array may, alternatively, be directly inserted into the cochlear nerve without residing in the cochlea. A representative ICS system is disclosed in U.S. Pat. No. 5,824,022, which is entitled “Cochlear Stimulation System Employing Behind-The-Ear Sound processor With Remote Control” and incorporated herein by reference in its entirety. Examples of commercially available ICS sound processors include, but are not limited to, the Harmony™ BTE sound processor, the Naida™ CI Q Series sound processor and the Neptune™ body worn sound processor, which are available from Advanced Bionics.

As alluded to above, some ICS systems include an implantable cochlear stimulator (or “cochlear implant”), a sound processor unit (e.g., a body worn processor or behind-the-ear processor), and a microphone that is part of, or is in communication with, the sound processor unit. The cochlear implant communicates with the sound processor unit and, some ICS systems include a headpiece that is in communication with both the sound processor unit and the cochlear implant. The headpiece communicates with the cochlear implant by way of a transmitter (e.g., an antenna) on the headpiece and a receiver (e.g., an antenna) on the implant. Optimum communication is achieved when the transmitter and the receiver are aligned with one another. To that end, the headpiece and the cochlear implant may include respective positioning magnets that are attracted to one another, and that maintain the position of the headpiece transmitter over the implant receiver. The implant magnet may, for example, be located within a pocket in the cochlear implant housing. The skin and subcutaneous tissue that separates the headpiece magnet and implant magnet is sometimes referred to as the “skin flap,” which is frequently 3 mm to 11 mm thick.

The present inventors have determined that conventional cochlear implants and stimulation systems are susceptible to improvement. For example, the magnet in some conventional cochlear implant is a disk-shaped axially magnetized magnet that has north and south magnetic dipoles which are aligned in the axial direction of the disk. Such magnets are not compatible with magnetic resonance imaging (“MRI”) systems, and may have to be surgically removed from the cochlear the implant prior to the MRI procedure and then surgically replaced thereafter. Other cochlear implants include a diametrically magnetized disk-shaped magnet that is rotatable relative to the remainder of the implant about its central axis, and that has a N-S orientation which is perpendicular to the central axis. The present inventors have determined that diametrically magnetized disk-shaped magnets are less than optimal because a dominant magnetic field, such as the MRI magnetic field, that is misaligned by at least 30° or more from the N-S direction of the magnet may demagnetize the magnet or generate an amount of torque on the magnet that is sufficient to dislodge or reverse the magnet and/or dislocate the associated cochlear implant and/or cause excessive discomfort to the patient.

More recently, cochlear implants with MRI-compatible magnet apparatus have been introduced. The MRI-compatible magnet apparatus have a case defining a central axis, a frame within the case that is rotatable relative to the case about the central axis, and three or more elongate diametrically magnetized magnets that are located in the frame in close proximity to one another and that are rotatable about their respective longitudinal axis relative to the frame. This combination allows the magnets to align with three-dimensional (3D) MRI magnetic fields, regardless of field direction, which results in very low amounts of torque on the magnets. Examples of such MRI-compatible magnet apparatus may be found in U.S. Pat. Nos. 9,919,154, 10,463,849, and 10,532,209. Another proposed magnet apparatus, which includes a single elongate magnet, is described in PCT Pat. Pub. No. 2020/092185 A1.

Although such MRI-compatible magnet apparatus have proven to be a significant advance in the art, the present inventors have determined that they are susceptible to improvement. For example, the field strength of MRI systems continues to increase and the amount of torque associated with placement of a particular MRI-compatible magnet apparatus into a 5 Tesla (5T) MRI magnetic field or a 7 Tesla (7T) MRI magnetic field may be significantly greater than the amount of torque associated with placement of the same MRI-compatible magnet apparatus into a 3 Telsa (3T) MRI magnetic field. The present inventors have also determined that it would be desirable to reduce the amount of magnetic material within a MRI-compatible magnet apparatus, thereby reducing the torque associated with a MRI magnetic field, without a corresponding reduction in the attraction force between the MRI-compatible magnet apparatus and the headpiece magnet, and without a corresponding increase in the size of the headpiece magnet. The present inventors have further determined that it would be desirable to more efficiently employ the magnetic field of the headpiece magnet, thereby further facilitating the use of less magnetic material within the MRI-compatible magnet apparatus.

SUMMARY

A method in accordance with at least one of the present inventions may include positioning a headpiece, including an axially magnetized magnet that defines a N-S direction and an antenna, on a portion of a user's head over an implanted cochlear implant including a magnet apparatus. The magnet apparatus may include a case, a frame within the case and rotatable about the central axis of the case, and only two elongate diametrically magnetized magnets that are located in the frame, that each define a longitudinal axis and a N-S direction, that are rotatable about the longitudinal axis relative to the frame, that are attracted to one another with an attraction force F1, and that are separated from one another by a fixed non-zero distance that is perpendicular to at least one of the longitudinal axes. When the distance between the axially magnetized magnet and the elongate diametrically magnetized magnets is 12 mm, there is a magnetic attraction force F2, which greater than the magnetic attraction force F1, between axially magnetized magnet of the positioned headpiece and the elongate diametrically magnetized magnets.

A system in accordance with at least one of the present inventions may include a head wearable external component, including an axially magnetized external magnet, and a cochlear implant having a cochlear lead, an implant antenna, an implant processor and an implant magnet assembly. The implant magnet assembly may include an implant magnet case defining a central axis, a frame within the implant magnet case and rotatable relative to the implant magnet case about the central axis of the implant magnet case, and only two elongate diametrically magnetized implant magnets that are located in the frame, that each define a longitudinal axis and have an individual magnetic dipole moment, that are rotatable about the longitudinal axis relative to the frame, and that are separated from one another by a fixed non-zero distance that is perpendicular to at least one of the longitudinal axes.

A magnet apparatus in accordance with at least one of the present inventions may include a case, a magnet frame within the case and rotatable about the central axis of the case, and only two elongate diametrically magnetized magnets that are located in the frame, that are separated from one another by a fixed non-zero distance, that each define a longitudinal axis and a N-S direction, that are rotatable about the longitudinal axis relative to the frame, and that are attracted to one another with a magnetic attraction force that is less than 3.0 N.

A magnet apparatus in accordance with at least one of the present inventions may include a case, a magnet frame within the case and rotatable about the central axis of the case, and only two elongate diametrically magnetized magnets that are located in the frame, that are separated from one another by a fixed non-zero distance, that each define a longitudinal axis and a N-S direction, that are rotatable about the longitudinal axis relative to the frame, and that define a total magnet volume that is less than about 20% to about 30% of the internal volume of the case.

A magnet apparatus in accordance with at least one of the present inventions may include a case, a magnet frame within the case and rotatable about the central axis of the case, and only two elongate diametrically magnetized magnets that are located in the frame, that are separated from one another by a fixed distance of about 3.8 mm to about 4.2 mm, that each define a longitudinal axis and a N-S direction, and that are rotatable about the longitudinal axis relative to the frame.

There are a number of advantages associated with such methods and apparatus. By way of example, but not limitation, the use of only two rotatable elongate diametrically magnetized magnets in the magnet apparatus reduces the amount of magnet material within the magnet apparatus, while the spacing between the elongate diametrically magnetized magnets reduces the magnetic attraction between the two magnets. The reduction in the magnetic attraction between the magnets within the magnet apparatus facilitates the use of an axially magnetized headpiece magnet, which is more magnetically efficient that a diametrically magnetized headpiece magnet due to the orientation of the magnetic field, because the magnets within the magnet apparatus will rotate into alignment with the magnetic field of the axially magnetized headpiece magnet. Accordingly, the present methods and apparatus employ less magnetic material within the magnet apparatus, the elongate diametrically magnetized magnets have less attraction force to one another due to the distance between the magnets, and there is less friction between rotating magnets and the inner surface of the case, thereby reducing the torque associated with placement of the magnet apparatus into a MRI magnetic field. As compared to a magnet apparatus with three or more elongate diametrically magnetized magnets, the present two-magnet apparatus also creates less of an MRI artifact (which may facilitate brains scans) and is less costly to manufacture. The present methods and apparatus also do so without reducing the magnetic attraction between the headpiece and the cochlear implant or increasing the size of headpiece magnet.

The above described and many other features of the present inventions will become apparent as the inventions become better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The following is a detailed description of the best presently known modes of carrying out the inventions. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the inventions.

As illustrated for example inFIGS.1-5A, an exemplary magnet apparatus (or “magnet assembly”)100includes a case102, with base104and a cover106, a frame108that is rotatable relative to the case, and two elongate diametrically magnetized magnets110that are rotatable relative to the frame. The magnet apparatus100may, in some instances, be employed in a system50(FIG.6) that includes a cochlear implant200with a magnet apparatus100(described below with reference toFIG.16) and an external device such as a headpiece400(described below with reference toFIGS.6and17). As is discussed in greater detail below, there are a variety of advantages associated with use of only two magnets that are not in closed proximity to one another. By way of example, but not limitation, the use of only two magnets that are spaced apart results in significantly less magnetic material, as compared to a similarly sized conventional MRI-compatible magnet apparatus, as well as a lower magnetic attraction force between the rotatable magnets which facilitates the use of an axially magnetized headpiece magnet, which is more efficient than the use of a diametrically magnetized headpiece magnet. As a result, a given level of magnetic attraction between the magnet apparatus and the headpiece can be achieved with less magnetic material in the magnet apparatus than would be necessary in a conventional MRI-compatible magnet apparatus and the same amount of magnetic material in the headpiece.

The case102in the exemplary magnet apparatus100is disk-shaped and defines a central axis A1, which is also the central axis of the frame108. The frame108is rotatable relative to the case102about the central axis A1over 360°. The magnets110rotate with the frame108about the central axis A1. Each magnet110is also rotatable relative to the frame108about its own longitudinal axis A2(also referred to as “axis A2”) over 360°. In the exemplary implementation illustrated inFIGS.1-5A, the longitudinal axes A2are parallel to one another and are perpendicular to the central axis A1. In other implementations, the magnets may be oriented such that the longitudinal axes thereof are at least substantially perpendicular to the central axis A1. As used herein, an axis that is “at least substantially perpendicular to the central axis” includes axes that are perpendicular to the central axis as well as axes that are slightly non-perpendicular to the central axis (i.e., axes that are offset from perpendicular by up to 5 degrees).

The exemplary case102is not limited to any particular configuration, size or shape. In the illustrated implementation, the case102is a two-part structure that includes the base104and the cover106which are secured to one another in such a manner that a hermetic seal is formed between the cover and the base. Suitable techniques for securing the cover106to the base104include, for example, seam welding with a laser welder. With respect to materials, the case102may be formed from biocompatible paramagnetic metals, such as titanium or titanium alloys, and/or biocompatible non-magnetic plastics such as polyether ether ketone (PEEK), low-density polyethylene (LDPE), high-density polyethylene (HDPE), ultra-high-molecular-weight polyethylene (UHMWPE), polytetrafluoroethylene (PTFE) and polyamide. In particular, exemplary metals include commercially pure titanium (e.g., Grade 2) and the titanium alloy Ti-6AI-4V (Grade 5), while exemplary metal thicknesses may range from 0.20 mm to 0.25 mm. With respect to size and shape, the case102may have an overall size and shape similar to that of conventional cochlear implant magnets so that the magnet apparatus100can be substituted for a conventional magnet in an otherwise conventional cochlear implant. The case102may also have an overall size and shape that is larger than that of conventional cochlear implant magnets in other embodiments. In some implementations, the diameter that may range from 9 mm to 17.4 mm and the thickness may range from 1.5 mm to 4.0 mm. The diameter of the case102in the illustrated embodiment is about 12.6 mm and the thickness is about 3.1 mm. As used herein in the context of the case102, the word “about” means±10%.

The exemplary frame108includes a disk112and only two receptacles114. A used herein, the phrase “only two” means “two and no more than two.” The receptacles114extend completely through the disk and that are defined by inner walls116. Suitable materials for the frame108, which may be formed by machining, metal injection molding or injection molding, include paramagnetic metals, polymers and plastics such as those discussed above in the context of the case102. Referring more specifically toFIG.4, there may be a relatively tight fit between the between the magnets110and the receptacles114. For example, the length of the receptacles114may be about 0.05 mm to about 0.20 mm greater than the length of the magnets110and the width of the receptacles may be about 0.05 mm to about 0.15 mm greater than the diameter of the magnets110in some implementations. As used herein in the context of the frame, the word “about” means±10%.

The magnets110in the exemplary magnet apparatus100are elongate diametrically magnetized magnets, and there are only two magnets110within the case102. As noted above, the phrase “only two” is used herein to mean “two and no more than two.” The exemplary magnets110are circular in a cross-section that is perpendicular to the longitudinal axis A2and, in some instances, may have rounded corners. Suitable materials for the magnets110include, but are not limited to, neodymium-boron-iron and samarium-cobalt. The frame108maintains the maintains the spacing between the magnets110. As is discussed in greater detail below, the magnetic attraction force F1between the two spaced magnets110, which is a function of the distance between the magnets, is such that the magnets will remain substantially aligned with one another in the N-S direction, as shown inFIG.5, in the absence of an external magnetic field that is strong enough to rotate the magnets out of alignment. The N-S orientation of each magnet will also be perpendicular to the central axis A1of the case102in the exemplary embodiment. Examples of magnetic fields that are strong enough to rotate the magnets110out of N-S alignment with one another are the headpiece magnetic field and the MRI magnetic field that are discussed below with reference toFIGS.6and8.

The magnets110may be located within tubes118formed from low friction material. Suitable materials for the tubes118include polymers, such as silicone, PEEK and other plastics, PTFE, and PEEK-PTFE blends, and paramagnet metals. The magnets110may be secured to the tubes118such that the each tube rotates with the associated magnet about its axis A2, or the magnets may be free to rotate relative to the tubes. The magnet/tube combination is also more mechanically robust than a magnet alone. The magnets110may, in place of the tubes118, be coated with the lubricious materials discussed below.

Friction may be further reduced by coating the inner surfaces of the case102and/or the surfaces of the frame108with a lubricious layer. The lubricious layer may be in the form of a specific finish of the surface that reduces friction, as compared to an unfinished surface, or may be a coating of a lubricious material such as diamond-like carbon (DLC), titanium nitride (TiN), PTFE, polyethylene glycol (PEG), Parylene, fluorinated ethylene propylene (FEP) and electroless nickel sold under the tradenames Nedox® and Nedox PF™. The DLC coating, for example, may be only 0.5 to 5 microns thick. In those instances where the base104and a cover106are formed by stamping, the finishing process may occur prior to stamping. Micro-balls, biocompatible oils and lubricating powders may also be added to the interior of the case to reduce friction. In the illustrated implementation, the surfaces of the frame108may be coated with a lubricious layer120(e.g., DLC), while the inner surfaces of the case102do not include a lubricious layer, as shown inFIG.5A. The lubricious layer120reduces friction between the case102and frame108.

Referring toFIG.6, the exemplary magnet apparatus100may part of an implanted cochlear implant200with a housing202(described in detail below with reference toFIG.16) that is employed in conjunction with an external device such as a headpiece400(described in detail below with reference toFIG.17) in a system50. The exemplary headpiece400includes, among other things, a housing402and an axially magnetized disk-shaped positioning magnet (or “external magnet”)410. The N-S direction of the external magnet410is at least substantially perpendicular (i.e., is perpendicular ±5%) to the implant recipient's skin. The respective configurations of the magnet apparatus100and the headpiece400are such that when the implanted magnets110are exposed to the magnetic field B1of the axially magnetized external magnet410, the magnetic attraction force F2between the external magnet410and the implanted magnets110is greater than magnetic attraction force F1between the two spaced apart elongate diametrically magnetized magnets110. The magnetic attraction force F2may be, for example, at least 10% greater than the magnetic attraction force F1, or may be, for example, at least 20% greater than the magnetic attraction force F1. As a result, the magnets110advantageously rotate out of alignment with one another, and into alignment with the magnetic field B1of the axially magnetized external magnet410. Put another way, the individual magnetic dipole moments of the elongate diametrically magnetized implant magnets110are oriented substantially in the direction of the axially magnetized external magnet410during attractive transcutaneous magnetic interaction with the axially magnetized external magnet410. The axially magnetized magnet410will also align with the center of the magnet apparatus100, thereby aligning the headpiece antenna with the implant antenna. The magnets110will return to the N-S-S aligned state illustrated inFIG.5when the headpiece400and the associated magnetic field B1is removed.

Another aspect of the exemplary magnet apparatus100is the impact resistance associated with the locations of the elongate diametrically magnetized magnets110. When the magnet apparatus100is subjected to an impact force (e.g., when the user bumps his/her head), the central portion of the case102will deflect inwardly. Advantageously, the magnets110are offset from the central axis A1of the case102by the distance D1(FIG.7), which reduces the likelihood of damage to the magnets as compared to a similar magnet apparatus where at least some of the magnets are located at or near the central axis A1.

Referring also toFIG.7, in the illustrated embodiment, the case102is about 12.6 mm in diameter, about 3.1 mm thick and has an internal volume of about 290 mm3. The diametrically magnetized magnets110may be N52 neodymium magnets or N55 neodymium magnets, while the axially magnetized headpiece magnet410may be a N55 neodymium magnet. The exemplary diametrically magnetized magnets110may each have a length ML of about 8.3 mm, a diameter of about 2.3 mm, and a volume of 69 mm3. As used herein in the context of the magnets110and410, the word “about” means±5%. The combined volume of the magnets110may be less than about 20% to about 30% of the internal volume of the case102and, in the illustrated implementation, is less than about 24% of the internal volume of the case102. The magnets110may be separated by a distance D1that is about 3.8 mm to about 4.2 mm, as are the frame receptacles114. The distance D1is perpendicular to at least one of the longitudinal axes A2, and is perpendicular to both of the longitudinal axes A2in the illustrated embodiment. The axially magnetized magnet410may have a height MH of about 7.6 mm and a diameter of about 11.45 mm. So configured, the magnetic attraction force F1between the magnets110is about 0.24 N, while the magnetic attraction force F2between the magnets110and the magnet410is about 0.29 N when there is a distance D2of 12 mm between the magnets110and the magnet410. As used herein in the context of the magnetic attraction force, the word “about” means±10%, so long as the magnetic attraction force F2is greater than the magnetic attraction force F1. In at least some embodiments, the magnetic attraction force F2is at least 10% greater than the magnetic attraction force F1.

It should be noted here that although the diametrically magnetized magnets110are identical to one another, are parallel to one another, and are equidistant from the central axis A1of the case102in the illustrated embodiment, the present magnet apparatus are no so limited. By way of example, but not limitation, the diametrically magnetized magnets110may have different lengths and/or may have different diameters and/or may be formed from materials having the same or different strength. Alternatively, or in addition, the diametrically magnetized magnets110may be non-parallel, and be different distances from the central axis A1of the case102. The configurations of the receptacles114would be adjusted to accommodate that of the magnets110.

Turning toFIG.8, when exposed to a dominant MRI magnetic field B2, the torque T on the magnets110will rotate the magnets about their axis A2(FIG.4), thereby aligning the magnetic fields of the magnets110with the MRI magnetic field B2. The frame108will also rotate about axis A1as necessary to align the magnetic fields of the magnets110with the MRI magnetic field B2. When the magnet apparatus100is removed from the MRI magnetic field B2, the magnetic attraction between the magnets110will cause the magnets to rotate about axis A2back to the orientation illustrated inFIG.5, where they are substantially aligned with one another in the N-S direction.

Another exemplary magnet apparatus is generally represented by reference numeral100ainFIGS.9-14. Magnet apparatus100ais substantially similar to magnet apparatus100and similar elements are represented by similar reference numerals. For example, the magnet apparatus100aincludes a case102, with a base104and a cover106, and only two magnets110. Here, however, the frame108aincludes a pair of relatively short rectangular portions122that are separated by a relatively long rectangular portion124. A pair of receptacles114adefined by tubular walls116athat are located within relatively short rectangular portions122. The elongate diametrically magnetized magnets110are located within the receptacles114aand are rotatable relative to the frame108a. The spacing between the magnets110is maintained by the frame108a. The distance between the magnets110and the headpiece magnet410will also be the same, or substantially the same. As such, the magnets110function in the manner described above, both with respect to one another and with respect to the headpiece magnet410. In the illustrated implementation, upper and lower curved flanges126and128extend radially outwardly from each of the relatively short rectangular portions122. The curvature of the free ends of the flanges126and128corresponds to the curvature of the surface within the case102that is in contact with the frame108a.

Suitable materials for the frame108ainclude those discussed above with reference to the case102and frame108. By way of example, but not limitation, the frame108amay be formed from a DLC coated metal material. In the illustrated implementation, the frame108ais formed from molded PEEK and an open region130defined between the upper and lower curved flanges126and128. The lack of molded material in the open region130prevents distortion of the molded frame108aas the frame cools during the manufacturing process. Material may be removed from other portions of a molded frame for the same reason. To that end, the exemplary fame108billustrated inFIG.15includes relatively long rectangular portion124bthat is thinner than the relatively long portion124.

The PEEK (or other molded material) may be protected from the heat associated with the welding of the case cover106to the base104through the use of a titanium ring132that is positioned against the inner surface of the case102. The titanium ring132may be omitted when a metal frame108ais employed.

One example of a cochlear implant (or “implantable cochlear stimulator”) including the present magnet apparatus100(or100a) is the cochlear implant200illustrated inFIG.16. The cochlear implant200includes a flexible housing202formed from a silicone elastomer or other suitable material, a processor assembly204, a cochlear lead206, and an antenna208that may be used to receive data and power by way of an external antenna that is associated with, for example, a sound processor unit. The cochlear lead206may include a flexible body210, an electrode array212at one end of the flexible body, and a plurality of wires (not shown) that extend through the flexible body from the electrodes212a(e.g., platinum electrodes) in the array212to the other end of the flexible body. The magnet apparatus100is located within a region encircled by the antenna208(e.g., within an internal pocket202adefined by the housing202) and insures that an external antenna (discussed below) will be properly positioned relative to the antenna208. The exemplary processor assembly204, which is connected to the electrode array212and antenna208, includes a printed circuit board214with a stimulation processor214athat is located within a hermetically sealed case216. The stimulation processor214aconverts the stimulation data into stimulation signals that stimulate the electrodes212aof the electrode array212.

Turning toFIG.17, the exemplary cochlear implant system60includes the cochlear implant200, a sound processor, such as the illustrated body worn sound processor300or a behind-the-ear sound processor, and a headpiece400.

The exemplary body worn sound processor300in the exemplary ICS system60includes a housing302in which and/or on which various components are supported. Such components may include, but are not limited to, sound processor circuitry304, a headpiece port306, an auxiliary device port308for an auxiliary device such as a mobile phone or a music player, a control panel310, one or more microphones312, and a power supply receptacle314for a removable battery or other removable power supply316(e.g., rechargeable and disposable batteries or other electrochemical cells). The sound processor circuitry304converts electrical signals from the microphone312into stimulation data. The exemplary headpiece400includes a housing402and various components, e.g., a RF connector404, a microphone406, an antenna (or other transmitter)408and an axially magnetized disk-shaped positioning magnet410, that are carried by the housing. The headpiece400may be connected to the sound processor headpiece port306by a cable412. The external positioning magnet410is attracted to the magnet apparatus100of the cochlear stimulator200(seeFIG.6), thereby aligning the antenna408with the antenna208. The stimulation data and, in many instances power, is supplied to the headpiece400. The headpiece400transcutaneously transmits the stimulation data, and in many instances power, to the cochlear implant200by way of a wireless link between the antennae. The stimulation processor214aconverts the stimulation data into stimulation signals that stimulate the electrodes212aof the electrode array212.

In at least some implementations, the cable412will be configured for forward telemetry and power signals at 49 MHz and back telemetry signals at 10.7 MHz. It should be noted that, in other implementations, communication between a sound processor and a headpiece and/or auxiliary device may be accomplished through wireless communication techniques. Additionally, given the presence of the microphone(s)312on the sound processor300, the microphone406may be also be omitted in some instances.

The functionality of the sound processor300and headpiece400may also be combined into a single head wearable sound processor that includes all of the external components (e.g., the battery, microphone, sound processor, antenna coil and magnet). Examples of head wearable sound processors are illustrated and described in U.S. Pat. Nos. 8,811,643 and 8,983,102, which are incorporated herein by reference in their entirety. Headpieces and head wearable sound processors are collectively referred to herein as “head wearable external components.”

The present inventions are applicable to systems that include cochlear implants which have already been implanted into the recipient. For example, a similarly sized magnet, or a magnet apparatus with a similarly sized case, may be removed in situ from an implanted cochlear implant (Step01). In some instances, the magnet or magnet apparatus may be removed from a pocket in the cochlear implant housing. The exemplary magnet apparatus100(or100a) described herein may be installed in place of the removed magnet or magnet apparatus (Step02). In some instances, the magnet apparatus100(or100a) may be inserted into the same pocket in the cochlear implant housing from which magnet or magnet apparatus was removed. Suitable removal and installation tools and techniques are illustrated and described in U.S. Pat. No. 10,124,167, which is incorporated herein by reference in its entirety. The headpiece magnet in the associated system may, if necessary, be removed from the headpiece or other head wearable external component and replaced with an axially magnetized magnet.

Although the inventions disclosed herein have been described in terms of the preferred embodiments above, numerous modifications and/or additions to the above-described preferred embodiments would be readily apparent to one skilled in the art. The inventions include any combination of the elements from the various species and embodiments disclosed in the specification that are not already described. It is intended that the scope of the present inventions extend to all such modifications and/or additions and that the scope of the present inventions is limited solely by the claims set forth below.