Patent Description:
Any discussion of the prior art throughout the specification in no way be considered as an admission that such prior art is widely known or forms parts of common general knowledge in the field.

A conventional implantable hearing aid system includes an external unit and an implantable unit, where the implantable unit is arranged between the skin and skull of a user of the system, and the external unit is arranged on to the skin and fixed to the implantable unit via magnetic forces. This implies that both the external unit and the implantable unit have a magnet. Implantable magnets associate with risks during MRI scan. As the patient enters the scanner, the powerful magnetic force of the scanner will attempt to force the implant magnet into alignment.

Many cochlear implant manufacturers use an open "soft silicone pocket" design, which uses a thin lip of silicone to hold a simple axial magnet in place.

With a soft silicone pocket design, there is minimal resistance to this powerful magnetic force, so the implant magnet can easily dislocate. A partially or fully dislocated implant magnet can cause extremely painful concentrated pressure. This often leads to incomplete scans and revision surgery to replace the magnet.

This is why magnet dislocation is the primary risk with cochlear implants. In an attempt to reduce the risk of magnet dislocation, companies with soft silicone pocket designs require a tight head bandage combined with a special rigid splint kit which makes the MRI scan complicated. The problem is that this tight head bandage does not eliminate the cause or the risk of magnet dislocation. Instead, this can put a painful pressure on the skin between partially dislocated implant magnet and the rigid splint. And the implant magnet can still dislocate and lead to revision surgery.

A solution to that is for example a rotatable, self-aligning implant magnet, however, the solution applies complicated mechanical design, and does not even guarantee high tesla MRI scan without any head bandage.

Furthermore, with a magnet in situ during a MRI scan will induce magnet-induced field distortions and consequent more pronounced artifacts preventing examination of a large area around the implant/magnet.

Furthermore, by fixating the external unit via magnetic forces causes a relatively high weight of the external unit, and also, a relatively large size of the external unit. This is not only uncomfortable for the user but also aesthetically unattractive. In addition, the implanted magnet has to be surgically removed or specially designed in case of MRI (Magnetic Resonance Imaging). Moreover, since the attractive forces between the magnets are limited, the external unit may move from the desired position and even fall down as a result of fast movements of the head (for example, when the patient jumps).

For a conventional coil arrangement where the transmitter coil and the receiver coil are arranged on either sides of the skin and in parallel planes, the coupling coefficient is very low because most of the magnetic field lines generated by transmitter coil is not picked up by the receiver coil, thus leading to poor energy transfer efficiency. In addition, as the two coils are located on either side of the skin, any change in coil separation, for example by way of increase in skin thickness, may result in rapid drop in the coupling coefficient between the two coils. In view of the efficiency problem, the external unit usually includes a relatively huge battery compartment or multiple batteries so that the implantable hearing aid system is useable for a usage period that doesn't cause annoyance for the user, for example requiring the user to frequently change batteries or recharge the battery compartment. Besides making the external unit aesthetically less appealing, the additional weight of the battery compartment or multiple batteries also require a stronger retention magnet that may possibly lead to discomfort and in extreme cases irritation or infection of the skin that is under constant magnetic attraction force generated between the retention magnet and implantable magnet.

For other types of hearing implants, other than cochlear implants, such as implants relying on bone-conduction for transmitting sound, a higher coupling coefficient can be used in two ways. Either the higher efficiency in power transmission through the skin is used to reduce the needed battery (and thereby reducing the size of the external sound processor) or used to elongate the battery lifetime (before recharge or battery change is needed). Importantly however, for bone conducting devices, the higher efficiency can be utilized for an increase of the Maximum Force Output or amplification. For bone conducting devices an increase in efficiency will directly translate into in increased amplification meaning that patients with more severe hearing loss can be treated.

Accordingly, the present disclosure provides an alternative coil arrangement for a wireless transcutaneous link and discloses an implantable hearing aid system that includes a wireless transcutaneous link where one or more of the above-mentioned shortcomings are addressed.

Document <CIT> describes an implantable medical device comprising a wireless transcutaneous link.

An aspect of the disclosure is to provide an implantable hearing aid system which provides a more aesthetic look and less visibility.

Furthermore, an aspect of the disclosure is to provide a more efficient power transmission through the skin and between an external unit and an implantable unit of the implantable hearing aid system.

Additionally, an aspect of the disclosure is to provide an implantable hearing aid system which is more tolerant to strong external magnet fields, such as from an MRI scanner.

In addition, an implantable hearing aid system for bone conducting, the higher efficiency can be utilized to increase the amplification and a broadened inclusion criteria. Further aspects, examples and embodiments disclosed herein are for exemplary purpose only and do not form part of the invention.

Several aspects of the apparatus and methods are described by various blocks, functional units, modules, components, etc. (collectively referred to as "elements"). Depending upon particular application, design constraints or other reasons, these elements may be implemented using other equivalent elements.

A hearing aid is adapted to improve or augment the hearing capability of a user by receiving an acoustic signal from a user's surroundings, generating a corresponding audio signal, possibly modifying the audio signal and providing the possibly modified audio signal as an audible signal to at least one of the user's ears. Such audible signals may be provided in the form of an acoustic signal transferred as mechanical vibrations to the user's inner ears through bone structure of the user's head.

The hearing aid may be replaced by a system comprising one or two hearing aids, and a "binaural hearing system" refers to a system comprising two hearing aids where the devices are adapted to cooperatively provide audible signals to both of the user's ears or the hearing aid of bone conduction type may be part of a bimodal system comprising a cochlea implant and a bone conduction hearing aid. The system may further include auxiliary device(s) that communicates with at least one hearing aid, the auxiliary device affecting the operation of the hearing aids and/or benefitting from the functioning of the hearing aids. A wired or wireless communication link between the at least one hearing aid and the auxiliary device is established that allows for exchanging information (e.g. control and status signals, possibly audio signals) between the at least one hearing aid and the auxiliary device. Such auxiliary devices may include at least one of remote controls, remote microphones, audio gateway devices, mobile phones, public-address systems, car audio systems or music players or a combination thereof. The audio gateway is adapted to receive a multitude of audio signals such as from an entertainment device like a TV or a music player, a telephone apparatus like a mobile telephone or a computer, a PC. The audio gateway is further adapted to select and/or combine an appropriate one of the received audio signals (or combination of signals) for transmission to the at least one hearing aid. The remote control is adapted to control functionality and operation of the at least one hearing aids. The function of the remote control may be implemented in a SmartPhone or other electronic device, the SmartPhone/ electronic device possibly running an application that controls functionality of the at least one hearing aid.

In general, a hearing aid includes i) an input unit such as a microphone for receiving an acoustic signal from a user's surroundings and providing a corresponding input audio signal, and/or ii) a receiving unit for electronically receiving an input audio signal. The hearing aid further includes a signal processing unit for processing the input audio signal and an output unit for providing an audible signal to the user in dependence on the processed audio signal.

The input unit may include multiple input microphones, e.g. for providing direction-dependent audio signal processing. Such directional microphone system is adapted to enhance a target acoustic source among a multitude of acoustic sources in the user's environment. In one aspect, the directional system is adapted to detect (such as adaptively detect) from which direction a particular part of the microphone signal originates. This may be achieved by using conventionally known methods. The signal processing unit may include amplifier that is adapted to apply a frequency dependent gain to the input audio signal. The signal processing unit may further be adapted to provide other relevant functionality such as compression, noise reduction, etc. The output unit may include an output transducer for providing mechanical vibrations either transcutaneously or percutaneously to the skull bone.

<FIG> illustrate different examples of an implantable hearing aid system <NUM>. The implantable hearing aid system <NUM> comprises an external unit <NUM> including an electronic unit <NUM> (not shown) operationally coupled to a first inductive coil arrangement <NUM> (not shown) configured to transmit power and/or data signals. Furthermore, the implantable hearing aid system comprises an implantable unit <NUM> which includes a second inductive coil arrangement <NUM> (not shown) configured to form a transcutaneous link <NUM> (not shown) with the first inductive coil arrangement <NUM> (not shown). The second inductive coil arrangement <NUM> is implanted within a part of an ear <NUM> of a user of the implantable hearing aid system <NUM>. The second inductive coil arrangement <NUM> has a hollow section <NUM> which is configured to receive a part of the earhook <NUM>. The external unit includes a housing <NUM> and an earhook <NUM>, and where the first inductive coil arrangement may be arranged within the earhook <NUM> or partially within the earhook <NUM> and partially within the housing <NUM>.

The implantable unit <NUM> may include an implantable stimulator and/or an implantable vibrator. In the specific examples of <FIG>, the implantable unit <NUM> includes an implantable stimulator which has an electrode array <NUM> for providing electrical stimulation to a cochlea <NUM> of the user.

<FIG> illustrates an example of the implantable hearing aid system <NUM> where the housing <NUM> is shaped as a Behind-The-Ear hearing aid with the earhook <NUM> attached onto. The earhook <NUM> goes around the top part of the ear <NUM> and applies a compression force between the earhook <NUM> and the housing <NUM> onto the skin of the ear <NUM>. A part of the earhook <NUM> is arranged proximal to the hollow section <NUM>. The hollow section <NUM> may be denoted as a through-going hole or opening.

<FIG> illustrates an example of the implantable hearing aid system <NUM> where the earhook is in a position which makes it possible for the user to remove the external unit <NUM> off the ear <NUM>.

<FIG> illustrates an example of the implantable hearing aid system <NUM> where the housing <NUM> and the earhook <NUM> are merged. The implantable unit <NUM> includes one or more of the following components: a processor unit, an implantable transducer and/or an implantable stimulator unit, a memory and a rechargeable battery <NUM>. The external unit <NUM> includes one or more of the following components: a processor unit, an implantable transducer and/or an implantable stimulator unit, a memory and a rechargeable battery <NUM>. In this specific example the external unit <NUM> includes a microphone and circuitry for driving the microphone, the earhook <NUM> and the housing <NUM>, and the implantable unit <NUM> includes the second inductive coil arrangement <NUM> a processor unit, an implantable stimulator unit, a memory and a rechargeable battery. In this specific example, the size of the external unit <NUM> has reduced significantly in comparison to the example described in <FIG>.

<FIG> illustrates an example of the implantable hearing aid system <NUM> where the housing <NUM> is shaped as an In-The-Ear hearing aid, and the housing <NUM> is connected to the earhook <NUM> via a connector part <NUM> which may include one or more wires for transmitting power and/or data signals between the first inductive coil arrangement <NUM> (not shown) of the earhook <NUM> and the electronic unit <NUM> (not shown) of the housing <NUM>. The earhook <NUM> may be attach to the ear <NUM> by a clamping force provided by a clamping mean (not shown) forming part of the earhook <NUM>.

The earhook <NUM> may include a needle which is configured to penetrate the ear <NUM> for fixating the earhook <NUM> to the ear <NUM>.

<FIG> illustrates an example of the implantable hearing aid system <NUM> where the housing <NUM> is shaped as a Behind-The-Ear hearing aid. The earhook <NUM> is connected to the housing via a connector part <NUM> (not shown), and the earhook <NUM> may be attach to the ear <NUM> by a clamping force provided by a clamping mean (not shown) forming part of the earhook <NUM>.

<FIG> illustrate different examples of the external unit <NUM> comprising the earhook <NUM> with the loop structure <NUM> and the electronic unit <NUM> arranged within the housing. <FIG> illustrates a specific example of the external unit <NUM> where the housing <NUM> is a behind-the ear hearing aid and connected to the earhook <NUM>. The loop structure <NUM> is partly arranged within the housing <NUM> and partly within the earhook <NUM> and where the loops <NUM> are arranged on the part of the loop structure which is within the housing <NUM>. Between the first end-face <NUM> and the second end-face <NUM> an opening <NUM> is formed for receiving a part of the ear <NUM> and the second inductive coil arrangement <NUM>. The current <NUM> applied to the coils <NUM> travels in an opposite direction as magnetic field lines <NUM> within the loop structure <NUM>, and when the external unit <NUM> is worn by the use, the magnetic field lines <NUM> travels through a hollow section of the second inductive coil arrangement <NUM> (not shown) which is part of the implantable unit <NUM> (not shown).

<FIG> illustrates a similar external unit <NUM> as described in <FIG>, however, the coils <NUM> are arranged within the earhook because of increasing the distance between the coils <NUM> and other units of the external unit <NUM>. Furthermore, the opening <NUM> between the end-faces (<NUM>,<NUM>) or the outer surface <NUM> of the housing <NUM> and a tip <NUM> of the earhook is clear seen.

<FIG> illustrates a specific example of the external unit <NUM> where the housing <NUM> is an in-the-ear hearing aid and connected to the earhook <NUM> via a connector part <NUM> which comprises one or more wires for transmitting current to the coils <NUM> and power and/or data signals to be communicated to the implantable unit <NUM> via the transcutaneuous link <NUM>. The earhook <NUM> is a separate part to the housing <NUM>, where the housing <NUM> is arranged into the ear canal of the user and the earhook <NUM> is applied onto the ear such that the opening <NUM> receives a part of the ear <NUM> of the user.

The external unit <NUM> in <FIG> is similar to the external unit <NUM> illustrated in <FIG>, however, the housing <NUM> is a behind-the-ear hearing aid. <FIG> illustrates a similar external unit <NUM> to the one illustrated in <FIG>, however, the earhook is configured to be fixed on the ear by a clamping force between at least the end-faces (<NUM>, <NUM>) of the loop structure <NUM>. The clamping force is provided by clamping means <NUM> which the first inductive coil arrangement <NUM> is applied onto and a spring unit <NUM>.

<FIG> illustrates a specific example of the external unit <NUM> where the housing <NUM> is merged with the earhook <NUM> such that when the external unit <NUM> is placed onto the ear both housing <NUM> and the earhook <NUM> are arranged on the pinna of the ear <NUM>. In this example, the implantable unit <NUM> includes a rechargeable battery, a processor unit and other units to drive the implantable unit <NUM> together with the external unit <NUM>. The external unit <NUM> includes at least one microphone, the electronic unit <NUM> and the first inductive coil arrangement <NUM>.

<FIG> illustrate different examples of the loop structure <NUM>. In <FIG> two groups of coils (<NUM>,10A,10B) are applied such that the density of the coils at the end-faces (<NUM>,<NUM>) of the loop structure <NUM> is higher than in the remaining parts of the loop structure. In <FIG>, the loop structure <NUM> is symmetric around a symmetry axis <NUM>, and the two groups of coils (<NUM>,10A,10B) are arranged at different positions on the loop structure <NUM> and on each side of the symmetry axis <NUM>. <FIG> illustrates a single group of coils (<NUM>, 10A) arranged on one side of the symmetry axis <NUM>, and in one example the single group of coils (<NUM>,10A) is arranged in the earhook <NUM> and outside the housing <NUM>. <FIG> illustrates the coils <NUM> being distributed along the loop structure <NUM> with a density being the same or partially the same.

<FIG> illustrate an example of the second inductive coil arrangement <NUM>. The second inductive coil arrangement <NUM> includes an implantable coil housing <NUM> which has a hollow section <NUM> with a chamfered inner side <NUM>. In another example, the hollow section may have an inner side which is straight. The chamfered inner side <NUM> is configured to guide the first inductive coil arrangement <NUM> for obtaining an optimal position of the loop structure <NUM> relative to the hollow section <NUM> of the second inductive coil arrangement <NUM>. A straight inner side provides a more fixed connection between the first inductive coil arrangement <NUM> and the second inductive coil arrangement <NUM>. The hollow section <NUM> may be tube shaped or box shaped or any shape which allows optimal inductive connection between the first <NUM> and the second <NUM> inductive coil arrangement.

<FIG> illustrates an implantable coil housing <NUM> which has a connection interface <NUM> to an implantable housing <NUM> (not shown). The implantable coil housing <NUM> may be arranged below the skin of the user, and the implantable housing may be arranged between the skin and the skull of the user. The implantable housing may include the transducer, such as a vibration-based transducer and/or an electrical stimulator. <FIG> illustrates a cross section of the implantable coil housing <NUM>. Within the implantable coil housing <NUM> a loop structure <NUM> is shown with coils <NUM> wound around a length of the loop structure <NUM>.

The implantable coil housing <NUM> has a first axis <NUM> which is parallel or partially parallel with the skin of the ear when the second inductive coil arrangement <NUM> is arranged below the skin of the ear <NUM> of the user. The radius or the diagonal of the hollow section is parallel with the first axis <NUM>. The implantable coil housing <NUM> has a second axis <NUM> which is parallel to the first axis <NUM> and centrally arranged in the hollow section <NUM>. When the end-faces (<NUM>, <NUM>) are aligned with the second axis <NUM> an optimal inductive connection is obtained between the first <NUM> and the second <NUM> inductive coil arrangement.

<FIG> illustrates an example of the second inductive coil arrangement <NUM> being integrated into a printed circuit board (PCB) <NUM>. Implementing the second inductive coil arrangement <NUM> into a PCB is for reducing the size of the coil arrangement <NUM>.

<FIG> illustrates different examples of a flexible unit <NUM> configured for providing a flexible connection between the housing <NUM> and the earhook <NUM>. In <FIG>, the flexible unit <NUM> is configured to move the earhook <NUM> in any directions which will result in an ideal position of both housing <NUM> and the earhook <NUM> onto the ear <NUM> of the user. For example, when moving the earhook <NUM> from a first position to a second position by applying a force to the earhook <NUM>, and release the force, the earhook <NUM> may either be kept in the second position or will return back to the first position. The second position of earhook <NUM> may be suitable for removing the external unit <NUM> from the ear <NUM>, and the first position of the earhook <NUM> may be suitable for obtaining an optimal connection between the first inductive coil arrangement <NUM> and the second inductive coil arrangement <NUM>.

In <FIG> the flexible unit <NUM> is configured to be snap coupled to the housing <NUM> and the earhook <NUM>, or in another example, the flexible unit <NUM> may be moulded into either the housing <NUM> or the earhook <NUM> and then snap coupled to either the housing <NUM> or the earhook <NUM>. The loop structure <NUM> comprises a first loop structure 8A which is be arranged within the housing <NUM> and a second loop structure 8B which is arranged within the earhook <NUM>, and both the first loop structure 8A and the second loop structure 8B forms the loop structure <NUM>. Within the flexible unit <NUM> another first end-face 26B of the loop structure and another second end-face 28B of the loop structure <NUM> are flexible connected, and the flexible connection provides that the first loop structure 8A and the second loop structure 8B are moveable relative to each other in a direction not parallel to an insertion direction <NUM> of the flexible unit <NUM>. One example for obtaining the flexible connection is for example by adapting the shape of one of the end-faces (26B, 28B) to fit with the shape of the another end-face (<NUM>, <NUM>). If the another first end-face 26B is for example round shaped then the another second end-face 28B is bowl shaped.

<FIG> illustrates a similar example of the flexible unit <NUM> as illustrated in <FIG>, however, a spring unit <NUM> is applied along a length of the loop structures (8A, 8B) in <FIG>. In this specific example, the spring unit <NUM> is applied along the length and at the end-faces (26B, 28B). The purpose of the spring unit <NUM> is to make sure that the first and the second end-faces (<NUM>, <NUM>) are optimal arranged relative to the second inductive coil arrangement <NUM> when the external unit <NUM> is arranged onto the ear <NUM> and the implantable unit <NUM> is arranged below the skin of the user. For example, when the user wants to apply the external unit <NUM> onto the ear <NUM>, the user has to move the earhook <NUM> into a position which allows the opening <NUM> to receive a part of the ear <NUM>, and when the user releases the earhook, the earhook will return back such that an optimal inductive connection between the first and the second inductive coil arrangement (<NUM>,<NUM>) is obtained.

The spring unit <NUM> may have one stable equilibrium position.

<FIG> illustrates another example of the spring unit <NUM>. In this example, the spring unit <NUM> is a metal spring which is shaped for obtaining two stable equilibrium positions of the earhook <NUM> relative to the housing <NUM>. The spring unit <NUM> is within the flexible unit <NUM> and separated from the loop structure <NUM>.

Alternative, the flexible unit <NUM> may be formed as a sleeve which is configured to receive the housing <NUM> at one end and at the other end the earhook <NUM>. The housing <NUM> and the earhook <NUM> is snap coupled to the flexible unit <NUM> preventing the flexible unit <NUM> to be accidently released from the housing <NUM> and the flexible unit <NUM>. The earhook <NUM> is configured to rotate in a direction around the centre of a hollow section of the flexible unit <NUM>.

<FIG> illustrates an example of the flexible unit <NUM>. An inner side of an opening <NUM> of the housing <NUM> includes protrusions which is configured to receive and seal the earhook <NUM>. The end <NUM> of the earhook which is configured to be inserted into the opening <NUM> includes an inner side which has protrusions configured to couple with the protrusions of the opening <NUM> while inserting the end <NUM> of the earhook <NUM> into the opening <NUM> of the housing, and thereby, the housing <NUM> is sealable connected to the earhook <NUM>. The earhook is rotatable around a centre of the opening <NUM>. The flexible unit <NUM> includes a pin <NUM> configured to rotate freely within a trace <NUM> of the flexible unit <NUM> and between a first fixed position 64A and a second fixed position 64B. When rotating the earhook <NUM>, the pin <NUM> moves within the trace <NUM>, and when the pin <NUM> reaches either the first or the second fixed position 64B, the earhook <NUM> is fixed into a position which allows the user to take off the earhook <NUM> from the ear <NUM> or which allows optimal inductive coupling between the first and the second inductive coil arrangement (<NUM>, <NUM>).

<FIG> illustrates an example of the external unit <NUM> where the end-face <NUM> of the earhook <NUM> and a circumferential edge of the opening <NUM> are shaped for preventing the user to assemble the earhook <NUM> with the housing <NUM> wrongly. In this specific example, the end-face <NUM> of the earhook <NUM> and the circumferential edge of the opening <NUM> are step formed (<NUM>, <NUM>), and an inward part <NUM> of the opening <NUM> is configured to receive an outward part <NUM> of the end-face <NUM>, and an outward part <NUM> of the opening <NUM> is configured to receive an inward part <NUM> of the end-face while the another end-faces (26B, 28B) snap couples <NUM>. No snap coupling between the another end-faces (26B, 28B) will appear, if for example, the outward parts meets when trying to assemble the earhook <NUM> and the housing <NUM>.

<FIG> illustrate different examples of the tip <NUM> of the earhook <NUM>. <FIG> illustrate an example of the tip <NUM> which includes a first part <NUM> mounted into the earhook <NUM> and which may comprise the first end-face <NUM> of the loop structure <NUM>. The first part has a hollow spring section <NUM> which is configured to receive a spring <NUM> and a tip part <NUM>. A second part <NUM> is configured to be assembled to the first part <NUM> such that the spring <NUM> and the tip part <NUM> are kept in place within the tip <NUM>. When the tip part <NUM> touches the skin of the ear the spring force of the spring <NUM> is configured to reduce the clamping force between the ear and the opening <NUM> of the external unit <NUM>. Thereby, the external unit <NUM> is adaptable to different ear thicknesses.

<FIG> illustrate yet another example of the tip <NUM>. The first part <NUM> is mounted into the earhook <NUM>, and the first part <NUM> includes the first end-face <NUM> of the loop structure <NUM>. The tip <NUM> includes a spring <NUM> wounded around the first end-face <NUM> of the loop structure <NUM>. The tip <NUM> includes a tip part <NUM> which comprises a hollow section configured to receive the spring <NUM> and a part of the first end-face <NUM> when assemble the tip part <NUM> onto the first part <NUM>. Thereby, the external unit <NUM> is adaptable to different ear thicknesses and the distance between the first end-face and the second end-face is reduced.

<FIG> illustrate different examples of the housing <NUM> of the external unit <NUM>. In <FIG>, an outer surface <NUM> of the housing <NUM> includes an outward pocket <NUM>. When the user applies the external unit <NUM> onto the ear <NUM>, and when the external unit <NUM> is in an optimal position for obtaining the optimal coupling between the coil arrangements (<NUM>, <NUM>), the outward pocket <NUM> is partially or fully inserted into the hollow section <NUM> from one side of the second inductive coil arrangement <NUM> while the tip <NUM> of the earhook is partially or fully inserted into the hollow section <NUM> from an opposite side to the one side of the second inductive coil arrangement <NUM>. A tactile signal is generated between the outward pocket <NUM> and the hollow section <NUM> of the second inductive coil arrangement <NUM> when the outward pocket <NUM> is partially or fully inserted into the hollow section <NUM>. The purpose of the tactile signal is to make the user aware of that the external unit <NUM> is in the optimal position.

In <FIG>, an outer surface of the housing which is directed towards the skin of the ear when the external unit <NUM> is arranged onto the ear includes multiple protrusions <NUM> for the purpose of reducing possible skin irritation. For example, the skin irritation may be due to heat generation between the housing and the skin of the ear, and by applying the protrusions <NUM> onto the surface <NUM>, air is able to travel through the spaces between the protrusions while the external unit <NUM> is on the ear <NUM>. The air cools the part of the ear which is in contact with the protrusions <NUM>.

<FIG> illustrates an implantable hearing aid system which includes at least another earhook 24B including a first secondary inductive coil arrangement 6A, and wherein the electronic unit <NUM> is configured to be connected to the first inductive coil arrangement <NUM> and the first secondary inductive coil arrangement 6A. In this example, the implantable unit <NUM> includes at least a second secondary inductive coil arrangement (not shown) configured to form another transcutaneous link (not shown) with a loop structure <NUM> of the first secondary inductive coil arrangement 6A and to receive power and/or data signals over the another transcutaneous link from the first secondary inductive coil arrangement 6A, and where the second secondary inductive coil arrangement is configured to be implanted fully or partially within a part of the ear of the user.

The second secondary inductive coil arrangement may be arranged within the opposite ear of the ear where the second inductive coil arrangement is arranged. Thereby, a binaural implantable hearing aid system is provided.

The second secondary inductive coil arrangement may be arranged within the same ear as where the second inductive coil arrangement is arranged. Thereby, the amount of power and/or data signals to be transferred in the transcutaneous link is increased without increasing the delay between the signals.

The implantable unit includes at least a second secondary inductive coil arrangement (not shown) configured to form another transcutaneous link with a loop structure of the first secondary inductive coil arrangement and to receive power and/or data signals over the another transcutaneous link from the first secondary inductive coil arrangement, and where the second secondary inductive coil arrangement is configured to be implanted fully or partially within a part of the ear of the user.

<FIG> illustrate an example of the second inductive coil arrangement <NUM> with a flange <NUM> which includes multiple holes for improving tissue anchoring of the coil arrangement <NUM>. The multiple holes may be ingrowth means for skin and/or tissue to groew into, and thereby, the second inductive coil arrangement <NUM> is anchored within the ear. In <FIG>, the implantable unit <NUM> is in place and the second inductive coil arrangement <NUM> is arranged between the skin layer <NUM> and the cartilage layer <NUM> of the ear <NUM>. After the implantation of the implantable unit <NUM> a healing clip <NUM> is mounted onto the ear and the coil arrangement <NUM> for keeping the coil arrangement <NUM> in place during interdigitation of tissue around the coil arrangement <NUM>. The healing clip <NUM> improves the healing process of the ear after the implantation and the anchoring of the coil arrangement <NUM> within the ear.

<FIG> illustrates an example where the first end-face <NUM> and the second end-face <NUM> of the loop structure <NUM> is arranged within the housing <NUM>, and where the loop structure <NUM> includes multiple loops. <FIG> illustrates an example where the second inductive coil arrangement <NUM> implanted in the ear, for example, in the antihelix region of the ear. In this specific example, the second inductive coil arrangement <NUM> includes multiple loops. <FIG> illustrates an example where the housing <NUM> is a behind-the-ear hearing aid arranged behind the ear, and where the multiple loops of the loop structure <NUM> is aligned with the multiple loops of the second inductive coil arrangement. The alignment of the loop structure <NUM> and the second inductive coil arrangement <NUM> implies that the multiple loops of both loop structure <NUM> and the coil arrangement <NUM> are parallel or about parallel.

Claim 1:
An implantable hearing aid system (<NUM>) comprising:
- an external unit (<NUM>) including an electronic unit (<NUM>) operationally coupled to a first inductive coil arrangement (<NUM>) configured to transmit power and/or data signals, and where the first inductive coil arrangement (<NUM>) includes a loop structure (<NUM>) with coils (<NUM>) wound around and along at least a part of length of the loop structure (<NUM>), and the loop structure (<NUM>) comprises an opening (<NUM>),
- an implantable unit (<NUM>) including a second inductive coil arrangement (<NUM>) configured to form a transcutaneous link with the loop structure (<NUM>) and to receive the power and/or data signals over the transcutaneous link, and where the second inductive coil arrangement (<NUM>) is configured to be implanted fully or partially within a part of an ear of a user of the implantable hearing aid system,
characterized in that:
the external unit (<NUM>) includes a housing (<NUM>) and an earhook (<NUM>), and where a first end-face (<NUM>) of the loop structure (<NUM>) is arranged within the earhook (<NUM>) and a second end-face (<NUM>) of the loop structure (<NUM>) is arranged within the housing (<NUM>), and in that the earhook (<NUM>) is configured to be formed such that the first end-face (<NUM>) of the loop structure is directed towards an outer surface of the housing (<NUM>), and the outer surface of the housing (<NUM>) is configured to be directed towards the skin of the ear when the external unit (<NUM>) is worn by the user.