Arrangement for a hearing aid

The arrangement is for controlling the connection for a hearing aid (15) with a fixture (13) anchored in the skull bone. A control arm (1) extends from a connector (17), disposed between the hearing aid (15) and an abutment (9), to a handle (3) disposed at a side of the hearing aid (15) where the handle (3) is reachable by a patient. Biasing means provides a biasing force for biasing the control arm towards the connector (17). The control arm (1) is in operative engagement with the biasing means and movable in a direction to counter-act the biasing force of the biasing means to release the abutment (9) from the connector (17).

TECHNICAL FIELD

The present invention relates to an arrangement for controlling a connection between a bone anchored implant and a bone conduction hearing aid.

BACKGROUND OF THE INVENTION

Bone anchored hearing aids are essential for the rehabilitation of patients suffering from some specific type of hearing losses for which traditional hearing aids are insufficient. This type of device consists of an external hearing aid with a vibrating transducer which is connected via a coupling to a skin penetrating abutment mounted on a fixture anchored in the skull bone. It is important that the coupling is sufficiently firm to avoid poor transmission of the vibrations but it is also important that the coupling is not too firm since it is also important that the hearing aid falls off in case of a sudden impact to avoid that the skull bone anchoring is damaged. In a coupling like this there is always coupling forces pressing components in the connection against the abutment. The coupling forces can be generated by a separate spring, a flexible material or by a magnet. The patient takes on and off the hearing aid daily so wear and tear durability of the coupling is also important.

Patents such as U.S. Pat. No. 5,735,790, U.S. Pat. No. 4,498,461 SE 89032718 and SE0102207 describe couplings where the force when connecting and disconnecting the hearing aid is quite high since it is important that the hearing aid is firmly coupled to the abutment. Especially it is not possible for the patient to use the hearing aid at all during the time it takes for the fixture in the skull bone to integrate with the skull bone, which takes around 3–6 months. The patients need to come to the hospital three times, first for the fixture insertion, then after a week to remove a healing cap and some gauze around the abutment and then after 3–6 months for the hearing aid fitting. If any of the couplings in U.S. Pat. No. 5,735,790, U.S. Pat. No. 4,498,461 SE 89032718 or SE0102207 would be used by the patient during the healing time, the fixture would most likely not integrate with the skull bone and come loose, due to the high load on the fixture when connecting and disconnecting the hearing aid. Arrangements, like the one described in SE503790, have several disadvantages and are not a solution to this since they do not at all reduce the force when connecting the hearing aid and when disconnecting the devices a significant rotation force is generated which is not desirable since the fixture in the bone is often screw shaped. A rotation of the fixture would definitely hinder the integration in the bone.

The high load on the connection also limits the lifetime of the hearing aid. In the hearing aid especially the vibrating transducer and the transducer suspension are affected by and worn out by the high forces when taking the hearing aid on and off. A limitation of the current systems is also that it is not possible to do more powerful devices since especially for high frequencies there is distortion of the sound due to the limited coupling force available in the current designs. If the coupling force could be significantly higher than in the current systems also more powerful devices for patients with more severe hearing losses could be rehabilitated with this type of hearing aid. In spite of the fact that bone anchored hearing aids have been available since more than 15 years ago, the above mentioned drawbacks remain. There is a need to provide a solution to the above outlined problems and drawbacks.

SUMMARY OF THE INVENTION

The arrangement of the present invention provides an efficient solution to the problems with the current designs of bone anchored hearing aid couplings. More specifically, the arrangement of the present invention includes a mechanical control arm system where the coupling force is counteracted in a way that the connection and disconnection of the hearing aid can be done without any force loading the fixture and the abutment. In this way, it is possible for the patient to start to use the hearing aid before the fixture is fully integrated in the bone which takes around 3–6 months, hence the patient will be rehabilitated much quicker. If the fitting is done in conjunction with the insertion of the fixture also a lot of costs for both patients and the health care system can be saved since this means the patients, who might have to travel long distances to the hospital, do not need to come back for an extra appointment to do the hearing aid fitting. The arrangement of the present invention also provides advantages for patients having a poor fixation of the fixture in the skull due to for example poor bone quality where the arrangement of the present invention can offer a minimal stress on the fixture in the bone. Another patient group in need for the arrangement of the present invention is small children where the skull bone is very soft. There are also patients who would prefer a coupling with control arms simply because they do not feel comfortable with the high forces that need to be applied when taking the device on and off. If the control arm system is used this will not only lower the stress on the fixture and the abutment but also on the hearing aid, hence the hearing aid will last longer. The control arm extends from a handle to the connection and transfers the force from the patients' fingers to the connection where the force is used for counteracting a coupling force in the connection. The arrangement of the present invention can have one or more control arms. The biasing means, generating the coupling force and/or counteracting the force on the handle on the control arm, may, for example, be a spring, an O-ring, a magnet or a flexible material.

The control arm extends from the center of the connection to the side of the hearing aid where the handle can be easily reached by the patient's fingers. The control arm can be connected to different types of connector principles. The connector has at least one coupling shoe which is in contact with the abutment when the hearing aid is connected to the abutment.

In a preferred embodiment, the control arm is connected to a connector with flexible coupling shoes. In another preferred embodiment the control arm is connected to a connector with a coupling shoe that is pressed against the abutment by a spring. The coupling shoes in both these two preferred embodiments can go either inside of the abutment where a coupling force from the connector is at least partly acting radially outwardly against the inside of the abutment, or the coupling shoes can go on the outside of the abutment where a coupling force from the connector is at least partly acting radially inwardly against the outside of the abutment.

In case of a flexible coupling shoe the control arm may be connected to the flexible coupling shoe either directly or through for example a wedge-like portion, in such a way that the force applied on the handle counteracts the coupling force. If the coupling shoe is pressed against the abutment by a spring the control arm may either be connected to the coupling shoe or to the spring. The connection to the coupling shoe or the spring may then be either direct or through for example a wedge-like portion, in such a way that the force applied on the handle counteracts the coupling force.

In a preferred embodiment the control arm, the handle and the coupling shoes are manufactured in one piece which include a plastic material.

In a preferred embodiment the control arm is connected to a magnetic connector where the coupling force is generated by a magnet in either of the abutment and the connector. In case of a magnetic interaction between the connection and the abutment the control arm can form a separating portion, for example a wedge, which presses the connector and the abutment apart when a force is applied to the handle on the control arm.

In case of a magnetic interaction between the connection and the abutment another preferred embodiment includes a sleeve on the connector that goes either around the outside of the abutment or inside of the abutment to avoid the magnetic coupling shoe from sliding off the abutment in radial direction. Without the connector sleeve a significantly stronger magnet would have been required to prevent the hearing aid from falling off. In this arrangement the control arm can be connected to the coupling sleeve. The coupling sleeve is moved in lateral direction in such a way that the magnetic coupling shoe can be moved freely in radial direction in relation to the abutment when a force is applied on the handle. By sliding the magnetic connector in radial direction the forces on the fixture may be significantly reduced compared to when pulling the connector away from the abutment in lateral direction. This arrangement only limits the force when disconnecting the abutment from the connector and does not limit the force when connecting the abutment to the connector. This may however be a cost efficient and sufficiently good arrangement for some patients.

The control arm may for example also be connected to a connector where the coupling force is generated by a spring on the abutment which presses the coupling shoe against the abutment. The control arm can then be designed in such a way that the control arm forms a wedge on the connector pressing the connector and the abutment apart when a force is applied to the handle on the control arm.

A preferred embodiment with only one control arm can be a cost efficient version of the arrangement of the present invention. However, with only one handle the patient needs to counteract the force on the handle by a force on the hearing aid. In that way, the suspension system of the vibrating transducer in the hearing aid may have to take up some of these forces. Therefore a preferred embodiment is a design with two control arms where the force on one of the arms can be counteracted by a force on the other control arm.

The control arm may also be connected to the connection in such a way that the control arm forms a wedge on the connector pressing the connector and the abutment apart when a force is applied to the handle on the control arm. This arrangement may be applied for any of the connector types mentioned above. However for most coupling designs this arrangement only limits the force when disconnecting the abutment from the connector and does not limit the force when connecting the abutment to the connector. This may however be a cost efficient and sufficiently good arrangement for some patients.

In a preferred embodiment the control arms are connected to a connector mounted on the hearing aid. If the patient needs to use the control arms during a longer period this is a good solution. However, if the patient just needs control arms during a shorter period it may be advantageous if the control arms can be removed. A preferred embodiment of the arrangement of the present invention includes a control arm interconnection. The control arm interconnection can be a mechanical coupling or an indication of fracture on the control arm where it can be disconnected or cut off when there is no more need for a control arm.

In a preferred embodiment the control arms are connected to a connector mounted on a healing interconnection unit which lateral side can be connected to the hearing aid. If the patient needs to use control arms to avoid loading the fixture in the bone during the healing period, the patient can then use the healing interconnection unit equipped with control arms and then when the fixture is integrated with the skull bone the healing interconnection unit can be removed from the hearing aid and the patient can take on and off the hearing aid without using any control arms. The connection on the healing interconnection unit can be any of the connector types mentioned above. If the abutment allows connection to it in two ways, for example both on the inside and the outside of the abutment, the connection on the healing interconnection unit does not necessarily have to be the same type of connector as the connector on the hearing aid that connects to the lateral side of the healing interconnection unit.

To use the hearing aid also during the first week when the gauze around the abutment needs to be held in place with a healing cap. A preferred embodiment includes a healing cap which lateral side has an abutment similar interface which may be connected to the connector on a healing interconnection unit or on a hearing aid, and where the other end of the healing cap can be connected to the abutment. The connection on the healing cap may be any of the connector types mentioned above.

An alternative healing cap design is a healing cap that may be connected to the outside of the abutment and where the abutment can go through the healing cap which would then offer an access to the abutment in such a way that the abutment may be connected to the connector on a healing interconnection unit or on a hearing aid also when the healing cap is mounted on the abutment.

In a preferred embodiment the distance between the handle and the center point of the connector is greater than 4 millimeters but less than 40 millimeters. If this distance is too short it will be difficult to reach the handles and if it is too long it might be bulky and not aesthetically pleasing. Of course, the control arms may be longer or shorter as needed.

For any off the above arrangements several different designs of a control arm is possible. Specifically the control arm can also be designed as a turning wheel. One practical advantage of the wheel design is that the user is less likely to inadvertently turn the handle by hitting something since there is no protruding part. The wheel is also symmetrical so that it is suitable both for left and right ears.

DETAILED DESCRIPTION

InFIG. 1a preferred embodiment of the arrangement100of the present invention is shown where the control arms1have handles3that are connected to a connector17that in turn is connected to a hearing aid15. By pressing the handles3against each other a force is transferred by the control arms1to the connection where this force is counteracting the coupling force. In this way, the connector17can easily be connected to and disconnected from the abutment9. The abutment9goes through the skin105and is fixated to a fixture13which is anchored in the bone104. The arrow inFIG. 1indicates a lateral direction (L).

InFIG. 2a preferred embodiment of the arrangement of the present invention is shown where the control arms1have handles3that are connected to coupling shoes5and where the coupling shoes5may be pressed against an outside102of the abutment9with the aid of a circular spring11that is disposed in a groove106defined in an outside108of the coupling shoes5and provides an radial biasing force (F1) directed inwardly to hold and bias the coupling shoes5against a connector plate19. The connector plate19projects through openings110(best seen inFIG. 3) defined in the coupling shoes5. The abutment9is mounted on a fixture13which may be attached to a skull bone104of a patient106. By pressing the handles3against each other against the inward radial biasing force (F1) of the spring11, an outward radial force (F2) is transferred by the control arms1to the connection where this force (F2) is counteracting the coupling force (F1) generated by the spring11. When the outward force (F2) is greater than the inward force (F1), the shoes5are separated to expand an opening defined between the shoes5so that the opening is greater than the largest diameter of the abutment9. In this way, the hearing aid15can be connected and disconnected from the abutment9without loading the fixture13.

FIG. 3shows the separated components of the connector17and the abutment9in the coupling inFIG. 2. The connector17has a connector plate19, the spring11and the coupling shoes5. The control arms1connect the handles3to the coupling shoes5of the connector17. The contact surface21of the connector plate19where the connector plate is pressed against the abutment is also shown inFIG. 3. When the outward force (F2) is removed, the force (F1) of the spring urges the shoes5together again until an inner surface116of the shoes5bears against a radial contact surface112of the connector plate19.

FIG. 4shows a preferred embodiment with a similar coupling as the one described inFIG. 2but where the control arms1are directly connected to a connection on a healing interconnection unit22to which the hearing aid15can be connected on the lateral side and which can be connected to the abutment9on the other side. The healing interconnection unit has an abutment similar interface415on its lateral side. The connector417without control arms on the hearing aid can be connected to either the abutment or the healing interconnection unit. The unit22may be modified to include any other type of connector on its contra lateral side and any type of abutment similar interface on the lateral side, dependent on which type of coupling is used to connect the hearing aid15to the abutment9.

FIG. 5shows a preferred embodiment with a similar coupling as the one described inFIG. 2but where the control arms1are directly connected to the circular spring11. In this case, the control arms1have been manufactured by an extension of the material in the spring11. By pressing the handles3against each other the coupling force generated by the spring11is counteracted and the hearing aid15can easily be connected and disconnected.

FIG. 6shows a preferred embodiment where the control arms111are connected to a flexible connector117which is connected to the inside of a female portion119on the lateral side of the abutment9. The control arms111have handles103. When the flexible connector117is seated in the abutment9the connector is pressed together inwardly against a biasing force of the connector117. Since the connector117is flexible the coupling shoe portion405on the connector presses outwardly on the inside of the female portion119of the abutment thus keeping it in place so that the protruding sections407of the portion405is urged against corner portions409of the female portion or cavity119. When the handles103are pressed together the connector117is further pressed together and the hearing aid15can easily be connected or disconnected from the abutment9without loading the fixture13.

FIG. 7shows a similar arrangement as the arrangement shown inFIG. 6but here the flexible connector117is connected to the inside of a female portion on the lateral side of a healing cap123that in turn is attached to the abutment9. The control arms111have handles103. The circular healing cap23is connected to the outside of the abutment9. The abutment9has a female portion inside so the flexible connector117can be directly connected to the abutment when the healing cap123has been removed. In this way the hearing aid15with control arms111can be used together with a healing cap123during the first week of healing and then the healing cap123can be removed and the connector117can be connected directly to the abutment9during the rest of the healing period. Of course, the healing cap123could be designed to connect to the inside of the abutment9instead but this might have resulted in a higher profile of the arrangement.

FIG. 8is a side view of an arrangement500which is similar to the arrangement shown inFIG. 2but where the control arm501can be disconnected from the coupling shoe505through a control arm interconnection502. The abutment9may be inserted through an opening532by pressing the handles503towards one another to widen the opening532against the biasing means of the spring11, as described in more detail above.

FIG. 9is an exploded perspective view of the components of the connection and of the abutment9in the arrangement500inFIG. 8. An important feature of the arrangement500is that the arms501are removable from the shoes505so that the user may simply remove the arms501when the fixture healing is completed. This feature may also make the manufacturing less expensive compared with having a healing interconnection unit as described inFIG. 4. The control arm501has a contact surface531resting against an inner surface537of the coupling shoe505. The control arm501has also a locking slot533into which a locking peg534on the coupling shoe505can be seated. In this way, the surface531is urged against the inside surface537. The control arm501has also an upper surface535resting against a connector flange530. These interfaces together form the control arm interconnection502. The control arms501may be removed by first removing the spring11and then removing the coupling shoes505and the control arms501. The coupling shoes505and the spring11may then be put back and then the connector may be used without control arms501instead, as desired.

FIG. 10is a side view of an arrangement600where the control arm601is connected to a wedge portion640which can be pressed in between the connector plate619and the abutment609so that the hearing aid15may be released from the abutment609without exerting a load the fixture13. The wedge portion640may be activated by urging the handles603and the arms601against the biasing force of the spring611so that the portion605may be snapped out from the abutment609against the biasing force of the spring641as the wedge portion640penetrates into a wedge-shaped cavity643formed between the abutment609and the connector plate619. In this way, there is no need to pull on the fixture13that is attached to the skull of the user.

FIG. 11is a side view of the arrangement shown inFIG. 10but where the control arms601has been pressed together to activate the wedge portion640to disconnect the portion605of the connector from the abutment609. The control arms601are urged apart or to be separated by the circular spring611. This arrangement is here shown together with a connector type that has a spring641seated in a grove on the inside of the abutment609. A coupling shoe605is a rigid body that can be snapped into the abutment609. When the coupling shoe605is seated in the abutment609the spring641presses against a conical portion642on the coupling shoe605to hold the shoe605in place by pressing the connector plate619against the abutment609.

FIG. 12is a cross sectional side view of an arrangement where the control arm701is connected to a circular connector sleeve750and where the connector and the abutment709are connected with a magnetic interaction. The connector sleeve750is a circular sleeve that extends down around the lateral portion of the abutment709and prevents the coupling shoe705to slide in a sidewise direction in relation to the abutment709. This takes advantage of the fact that it is generally relatively easy to slide two magnets relative to one another but difficult to separate the magnets by pulling them apart against the magnetic force. The control arms701and the connector sleeve750are kept in position by the metal spring plate751. In this way, the user simply presses the hearing aid15against the skull to counter-act the biasing force of the spring plate751so that the magnet705moves relative to the sleeve750until a surface752of the magnet705is either flush with or extends beyond an outer surface754of the sleeve750, (as best shown inFIG. 13. The user then moves the magnet705sideways relative to the magnet709until the magnets are separated. This makes it possible to separate the magnets from one another without having to pull the magnets apart against the magnetic forces of the attracting magnets705,709.

FIG. 13is a cross sectional side view of the arrangement shown inFIG. 12but where the connector sleeve750has been moved in a lateral direction away from the abutment709to allow the connector to be moved sidewise in relation to the abutment. The connector sleeve750is moved in lateral direction by pulling the handles3in lateral direction against a biasing force of a spring mechanism751at the same time as a counteracting pressure is applied at the lateral side of the hearing aid15.

FIG. 14is a perspective side view of an alternative design of the arrangement shown inFIG. 12, but here the control arm301has been designed as a wheel instead of a straight arm.FIG. 15is a cross sectional side view of the embodiment inFIG. 14. The control arm301has a threaded portion351in the center instead of a spring arrangement as inFIG. 12. In this way the connector sleeve350can be moved in lateral or contra lateral direction by turning the control arm301in either direction. The periphery of the control arm301acts as a handle303for the patient to control the connection.

For all of the above embodiments several alternative designs and combinations are possible and the invention is not limited to the preferred embodiments presented above. While the present invention has been described in accordance with preferred compositions and embodiments, it is to be understood that certain substitutions and alterations may be made thereto without departing from the spirit and scope of the following claims.