HEARING AID

Abstract: The invention relates to a hearing aid of the type in which the sound is amplified and, via air conduction, is made to stimulate the eardrum to vibrate. A hose, tube or the like (2) is permanently implanted surgically in the skull bone (7) or is connected thereto in order to convey amplified sound from the electronics part (4) of the hearing aid to the middle ear (1) for stimulating the eardrum (5) to vibrate from the inside. In this way, the auditory meatus is left free and no intervention needs to be carried out on the eardrum, the inner ear or the bones of the middle ear.

Description: Hearing aid The present invention relates to a hearing aid of the type in which the sound is amplified and, via air conduction, is made to stimulate the eardrum to vibrate. For persons with impaired hearing, the hearing aids mainly used today are those based on the principle that the sound is amplified and conveyed into the auditory meatus and stimulates the eardrum from the outside. In order to prevent feedback problems in these appliances, the auditory meatus is almost completely plugged by a hearing plug or by the appliance itself. This causes the user a sensation of pressure, discomfort and sometimes even eczema. It is already known to use hearing aids which leave the auditory meatus free, see for example US 5,411,467 and US 5,318,502, which hearing aids are both connected to the inner ear. Such a connection, however, necessitates an intervention on the inner ear, which entails a relatively complicated surgical implantation. It is also already known, from US 5,282,858 and US 4,988,333, to secure part of the hearing aid on the bones of the middle ear. Λlthough such a solution leaves the auditory meatus free, it nevertheless requires an extensive surgical implantation with intervention on the bones of the middle ear. The object of this invention is to make available a hearing aid of the type in which, via air conduction, the sound stimulates the eardrum to vibrate, at the same time as the auditory meatus is left free, and without intervention on the eardrum, the inner ear or the bones of the middle ear. According to the invention, the sound is conveyed in to the middle ear via a hose, tube or the like which has been permanently implanted surgically in the skull bone in order in this way to stimulate the eardrum to vibrate from the inside. By means of the invention, it is possible for an air-conduction appliance to be used at the same time as the auditory meatus is left free. The sound vibrations in the air in the middle ear set the eardrum in vibration. The eardrum is stimulated in this way from the inside instead of from the outside, i.e. a direct acoustic coupling to the middle ear. The advantage of this is that the auditory meatus can then be left free since no hearing plug is needed, as is the case in traditional hearing aids . In this way, discomfort and irritation of the auditory meatus can be avoided. A number of different embodiments of the invention are shown diagrammatically in the attached drawings, where Figure 1 shows the principle of the hearing aid with external electronics module, Figure 2 shows an alternative construction with partially external electronics module, Figure 3 shows a further variant in the form of a fully implanted electronics module, and Figure 4 shows an example of how the actual hearing aid can be constructed. Figure 1 shows diagrammatically the auditory organs with external ear, auditory meatus and middle ear 1. A hose, tube or similar air-conduction channel 2, permanently anchored surgically in the skull bone, preferably in the mastoid bone behind the external ear, conveys the sound from the electronics module 4 of the hearing aid to the middle ear 1. The electronics module is thus placed externally, at a distance from the middle ear, at a location where it is easily accessible for servicing, battery replacement, repairs, and the like. The electronics module 4 of the hearing aid contains, in addition to a battery 11, a microphone 10 whose signal is supplied via an amplifier to a receiver 12 which is connected to the inlet end of the hose, see Figure 4. The hearing aid is otherwise of the traditional type and is therefore not described in any more detail here. The sound vibrations which are generated by the electronics module 4 of the hearing aid are conveyed via the channel 2 to the middle ear 1, whereupon the air in the middle ear is set in vibration and stimulates the eardrum 5 to vibrate. The eardrum is thus stimulated from the inside, from the middle ear, instead of from the outside, as is the case with traditional air-conduction appliances. The eardrum remains intact. In Figure 1, the electronics module 4 of the hearing aid is placed externally and the sound is conveyed via a passage 3 through the skin 6 in^to the middle ear. The passage through the skin consists of a tissue-compatible material and can be anchored, for example, in the skull bone 7 by means of a screw-shaped fixture 8 in a similar manner as with bone-anchored hearing aids of the type shown in SE 8107161-5. The tube or hose 2 is made of a tissue-compatible material, for example a silicone material or Teflon. The hose can either be introduced into a channel drilled beforehand in the skull bone 7, as is shown in the figures, or else can lie in a reamed-out groove, recess, in the bone surface and conveyed along the side of the auditory meatus as far as the middle ear so that it opens out to the inside of the eardrum. Running a channel to the middle ear is known per se for the purpose of effecting ventilation of the middle ear, see SE 9603175-2 which describes a ventilation tubing in two parts for ventilating the middle ear. The electronics module 4 is arranged in a detachable manner on the hose 2, for example so that it can be replaced when need be. In this case, a hose seal is arranged to prevent water and bacteria, for example, from penetrating inside the channel. Even when the electronics module is in place, the inlet opening of the hose can have some form of protection in the form of filter or fine-mesh net which does not obstruct the sound vibrations but prevents undesired material from penetrating inside the channel . In Figure 2, parts of the hearing aid 4 are located under the skin level, and the sound is conveyed from a receiver which lies under the skin level. Figure 3 shows a further variant in which the hearing aid 4 is encased and fully implanted under the skin. In this case, the battery is charged wirelessly, for example by induction, from an external charger unit. Figure 4 shows in greater detail how the hearing aid 4 with passage 3 through the skin can be constructed, see above. The passage 3 through the skin is designed as an open sleeve in which the electronics components are recessed. The bottom part of the sleeve has an opening for the hose 2 and is anchored in or against the skull bone by means of the previously mentioned fixture 8. The invention is not limited to the examples which have been shown above, but can be varied within the scope of the attached patent claims.

Claims: PATENT CLAIMS 1. Hearing aid of the type in which the sound is amplified and, via air conduction, is made to stimulate the eardrum to vibrate, characterized by a permanently surgically implanted hose, tube or similar air-conduction channel (2) for conveying sound amplified by the electronics part (4) of the hearing aid into the middle ear (1) for stimulating the eardrum (5) to vibrate from the inside. 2. Hearing aid according to Patent Claim 1, characterized in that the electronics part (4) of the hearing aid is placed at a distance from the middle ear (1) at a location where it is easily accessible for servicing, repair and replacement. 3. Hearing aid according to Patent Claim 2, characterized in that the electronics part (4) of the hearing aid is placed externally and is connected to the air-conduction channel (2) via a passage (3) through the skin. 4. Hearing aid according to Patent Claim 2, characterized in that the electronics part (4) of the hearing aid is placed partially under the skin. 5. Hearing aid according to Patent Claim 2 , characterized in that the electronics part (4) of the hearing aid is encased and surgically implanted under the skin. 6. Hearing aid according to Patent Claim 3 , characterized in that the passage (3) through the skin is anchored in the skull bone (7) by means of a screw-shaped fixture (8) . 7. Hearing aid according to Patent Claim 1, characterized in that the tube or hose (2) is arranged in a channel which has been drilled beforehand in the skull bone and which extends from the location where the electronics module is to be anchored as far as the middle ear, where the channel opens out. 8. Hearing aid according to Patent Claim 1, characterized in that the tube or hose (2) is arranged in a groove or recess made in the surface of the skull bone so that the tube or hose is passed along the side of the auditory meatus and the eardrum as far as the middle ear and opens out to the inside of the eardrum (5) . 9. Hearing aid according to Patent Claim 1, characterized in that the electronics part of the hearing aid is arranged detachably on the hose or tube (2) . 10. Hearing aid according to Patent Claim 1, characterized in that that end of the hose or tube (2) which adjoins the electronics part (4) of the hearing aid has a filter or the like which transmits the sound vibrations but prevents undesired objects from penetrating inside the hose or tube (2) .

Inventors: JOHANSSON PATRIK, JOHANSSON, PATRIK
Applicants: JOHANSSON PATRIK, NOBEL BIOCARE AB, JOHANSSON, PATRIK, NOBEL BIOCARE AB (PUBL)
Application year: 1998
Main classification: H04R25
IPC codes: H04R25