Patent Application
20150055809
The present invention concerns a hearing device comprising a BTE (Behind-The-Ear) unit, which is adapted to be mounted behind or on the ear of a user and further comprising an air filled tube, which comprises a bony seal part.
There exist many different types of conventional hearing devices, for example ITE (In-The-Ear), ITC (In-The-Canal), CIC (Completely-In-the-Canal) and BTE (Behind-The-Ear), which are characterized by the way they are fitted to the ear of a user, see for example US 2008/0123889 and references therein. The components of the first three types are mainly located in the ear or ear canal of the user. The BTE hearing device is mounted behind or on the ear of a user. It typically comprises a power source, a microphone, an amplifier and a receiver (speaker), which is connected to an air filled tube that has a distal end that can be fitted in the ear canal of the user. Sound generated by the receiver can be transmitted through the air filled tube to a tympanic membrane of a user's ear canal.
A major problem for hearing device users is the occurrence of various acoustic effects when using a hearing device, e. g., comb filter effect, sound oscillations or occlusion. The comb filter effect result through the simultaneous occurrence of device generated and natural sound in the ear canal of the user. Sound oscillations are generated in the device through sound reflections off the ear canal to the microphone of the hearing device. The occlusion corresponds to an amplification of a person's own voice when the person's ear canal is blocked. Especially occlusion is a well known issue for hearing device users. In the prior art the occlusion was avoided by not completely closing the ear canal, e. g., by applying open dome solutions, by using ear canal molds or ITE hearing instruments with large vent openings. Vent openings, however, lead to feedback problems known as “howling”, where the hearing instrument emits a characteristic noise often with pure tone content. Avoiding the howling by anti-feedback processing results in deteriorated sound quality in situations where high amplification. The occlusion can, however, be avoided almost entirely by means of hearing devices which interface with the ear canal in the deeper bony portion of the ear canal.
GB 962,780 presents a deaf aid with a microphone disposed on the ear. The microphone is constructed so as to be accommodated in the external auditory meatus (ear canal), while amplifier parts are arranged behind the ear. The shape of the microphone is adapted to the shape of the external auditory meatus.
In U.S. Pat. No. 5,201,007 an earmold and a method of manufacturing an earmold for a hearing aid is presented. The earmold includes an acoustic conduction tube with a flexible flanged tip, e. g., a disk that exerts negligible pressure on the wall of the ear canal when in use. The disk of the acoustic conduction tube is at least as deep in the ear canal as the osseous portion (bony portion) of the ear canal when in use and conforms to the ear canal. The disk can have one or more vent holes.
WO 97/45074 A1 shows a thin diaphragm for contacting an individual's tympanic membrane which is used as a hearing improvement device. The diaphragm is sufficiently efficient to vibrate in response to sound stimuli so as to displace the tympanic membrane when in use. The edge of the diaphragm can be attached to a holder by a compliant member. The holder serves to hold the diaphragm against the tympanic membrane and can for example be a horn, a bumper, an adhesive or a clamp.
U.S. Pat. No. 6,137,889 presents a device to be worn in the ear of a subject with a vibrationally conductive assembly to provide a direct vibrational drive to the tympanic membrane. The device includes a vibratory transducer positioned within the ear canal proximal to the tympanic membrane. The vibratory transducer vibrates a thin elongate vibrationally conductive member, such as a filament, that is coupled to the tympanic membrane via a tympanic coupling element. The device can be a hearing aid.
In WO 01/50815 A1 a canal hearing device with a subminiature filament assembly to vibrate and drive the tympanic membrane is presented. The filament assembly is dynamically coupled to a stationary vibration force element positioned in the ear canal at a distance from the tympanic membrane when in use. The filament assembly comprises a vibratory element to respond to dynamic forces imparted by the vibrational force element and a vibrational shaft element for transferring audible vibrations from the vibratory element to the tympanic membrane, when in use.
US 2004/0165742 A1 shows a canal hearing device with a main module, a tubular insert, a sound conduction tube, a primary seal and a secondary seal. The main module is positioned in the cartilaginous region of the ear canal and axially and removably connected to the tubular insert. The tubular insert comprises the sound conduction tube and the cylindrically hollow primary seal, which is medially positioned in the bony region. The secondary seal is laterally positioned in the cartilaginous region to provide an additional acoustic sealing. The secondary seal is sufficiently vented to provide a path of least acoustic resistance for occlusion sounds within the ear canal. The tubular insert can comprise a coiled skeletal frame.
WO 2010/077781 A2 presents a hearing aid transducer. The transducer is configured to adapt itself to variations in the surface of a tympanic membrane and to slide over the migrating membrane without lubrication. The hearing aid transducer comprises a biocompatible carrier and a driving element attached to the carrier. The carrier has a surface which is shaped to fit a tympanic membrane or ear canal. The surface supports a plurality of microscopic setae. The driving element can receive electrical power from a photovoltaic cell.
U.S. Pat. No. 5,606,621 shows a hybrid BTE and CIC hearing aid with a BTE component and a CIC component. The BTE component is worn behind the ear of a patient and contains a microphone, a battery and amplifier circuitry. The CIC component is worn in the bony portion of the ear canal of the patient and contains the hearing aid receiver, which is connected to the amplifier means. The receiver of the CIC component is connected to the BTE component by a thin flexible wire cable.
EP 0997057 shows a BTE hearing aid wherein a very thin air filled tube with a diameter of less than 0.9 mm is provided for feeding sound from the receiver and into the ear.
The object of the present invention is to provide an improved hearing device.
The present invention provides a hearing device comprising a BTE (Behind-The-Ear) unit, and an air filled tube. The BTE unit comprises a power source, a microphone, an amplifier, and a receiver and is configured to be mounted behind or on the ear of a user. The air filled tube has a proximal end and a distal end. The proximal end of the air filled tube is connected to the receiver of the BTE unit and at least one flexible sealing part is provided at the distal end. The flexible sealing part comprises at least one core hole permeable for sound transmitted from the air filled tube through a core pathway. The air filled tube is configured to be arranged in a user's ear canal to transmit sound generated by the BTE unit to a tympanic membrane of the user. The at least one flexible sealing part is adapted to be arranged in a bony portion of the user's ear canal and its diameter is adapted to at least have the same diameter as the bony part diameter of the ear canal of a user to close the ear canal of the user.
One aspect of the invention is to reduce the occlusion effect by inserting a sealing part deep into the ear canal to the bony portion. Another aspect is the reduction of other acoustic effects, e. g., sound oscillations or the comb filter effect, as the sealing part closes the ear canal and sound cannot enter or escape the ear canal or the sound that enters or escapes the ear canal is dampened. The microphone is arranged on the BTE unit, therefore backscattered sound from the ear canal will reach the microphone with a significantly reduced sound pressure level compared to ITC, ITE and CIC devices. The hearing device is effective and easy to produce since no wires are needed inside the air filled tube. Another aspect of the invention is that the receiver (speaker) is protected in the BTE unit, which makes the device easy to maintain. The in-the-ear-canal part of the hearing device can have a smaller dimension, since it does not contain electrical parts. This increases the design freedom and allows the device to be useable for a higher number of different ear canal sizes and shapes, in which the sealing part can be physically conformed. The audiological fitting range can be high due to the absence of a vent channel. The flexible sealing part in the bony portion of the ear canal allows a more efficient noise reduction and a higher directionality to be experienced by the user, as all sound is generated from signals in a signal processing path, which may also be controlled by suitable processing schemes. Especially users with ski slope losses, which are users that are seriously impaired for high frequencies but have a normal hearing for low frequencies and experienced users, who want a good sound quality and need effective noise reduction in order to improve their speech understanding in noise situations benefit from the improved noise reduction efficiency. The invention is also especially advantageous for external signal sources such as sound from TVs, cell phones, or the like, as no or nearly no destructive interference between direct sound and amplified sound occurs.
In a preferred embodiment the flexible sealing part is a soft interchangeable dome shape seal, which is connected to the distal end of the air filled tube. The distal end of the air filled tube can also be formed in a dome shape seal. In an alternative embodiment the air filled tube contains several seals. In another embodiment the sealing part can also be an individually shaped ear canal mold, which is formed into the shape of an individual user's ear canal. Preferably the ear canal mold is connected to the distal end of the air filled tube. The distal end of the air filled tube can also be formed into an individually shaped ear canal mold. The ear canal mold is preferably covered in a soft material or made of a soft material to conform to the ear canal of a user and to prevent discomfort. Further the air filled tube can also be an interchangeable tube. The ear canal mold and dome shape seals can also be combined, for example in a coaxial or axially aligned arrangement on the air filled tube.
Preferably the flexible sealing part is of a soft material. More preferably the part of the flexible sealing part which is in contact with the bony portion of the ear canal, when the sealing part is in use, is of a very soft material to prevent injuries of the sensitive skin of the ear canal, especially for deep insertion of the flexible sealing part in the bony portion of the ear canal. Most preferably the material of the flexible sealing part is adapted to conform to the form of the ear canal.
In a preferred embodiment the air filled tube is of a material that is rigid enough as to allow for insertion of the air filled tube into the ear canal without the need of further means of insertion. Preferably the air filled tube is soft enough to allow for conformation of the tube to the ear and ear canal of a user.
The distal end of the air filled tube is preferably connected to the flexible sealing part in such a way, that the flexible sealing part stays connected to the air filled tube when the air filled tube is inserted or withdrawn from the ear canal of a user. The connection between the air filled tube and the sealing part can be primarily mechanical or primarily chemical. Preferably one interface section of the air filled tube is connected to an interface section of the sealing part. The interface of the interface sections can be connected primarily mechanically or primarily chemically. The type of connection is preferably chosen in dependence of the material choice and the physical shape of the interface between the two materials.
In a preferred embodiment the air filled tube is of a first material and the sealing part of a second material. The two materials can have different mechanical properties. Preferably the first material is more rigid than the second material and the second material is softer than the first material. The air filled tube and the flexible sealing part, e. g., a dome, can be cast by means of 2 k technology. In one embodiment the two different materials are cast in a two-shot molding process to produce the air filled tube and the flexible sealing part. Alternatively the two different materials can also be cast by overmolding. In a preferred embodiment the flexible sealing part is a dome of TPE (thermoplastic elastomer), silicone or materials with similar properties. The tube can be made of PEBA (polyether block amide), PEBAX or similar TPE (thermoplastic elastomer) or TPU (thermoplastic polyurethane) materials. In one embodiment the tube and sealing part are virtually inseparable due to a strong mechanical and/or chemical bond between them.
The hearing device can have one or more optional sealing parts on the portion of the air filled tube, that is inserted into the ear canal of the user. Preferably the optional sealing parts are included on the surface of the air filled tube that is in the cartilaginous region of the ear canal. The optional sealing parts can be optional seals connected to the air filled tube or they can also be part of the air filled tube formed into an optional sealing part. The optional sealing parts can for example have a dome shape, prong shape perpendicular to the tube axis or similar shapes that can be used to position the air filled tube in the ear canal, e. g., in the center of the ear canal. As an option the air filled tube can contain randomly distributed soft prongs shaped on its surface to position the air filled tube in the center of the ear canal. Preferably the optional prongs are of a soft material. The optional prongs can include holes for venting.
In a preferred embodiment the flexible sealing part has one or more prongs on its surface, which in use of the flexible sealing part face in the direction of the tympanic membrane. Preferably the prongs serve to prevent contact between the sealing part and the tympanic membrane, which can cause discomfort for the user. In one embodiment the contact between prongs and tympanic membrane can be felt by the user, which serves as a warning for the user. Alternatively an alarm can be sounded when the prong is deformed due to contact with the tympanic membrane, for example by piezoelectric properties of the prong material which induces a current to activate an alarm due to the deformation. The prongs are preferably of a very soft material that is at least softer than the tympanic membrane to prevent hurting the tympanic membrane. The prongs can have lengths between 0.1 mm and 10 mm, such as between 0.5 mm and 7.5 mm and preferably between 1 and 5 mm. The different prongs can have different lengths. Preferably the lengths of the prongs are equal for all prongs. The prongs are preferably scattered over the surface of the flexible sealing part in a symmetric way. The prongs can also be randomly scattered on the surface of the flexible sealing part. In a preferred embodiment the flexible sealing part is a dome shape seal with prongs.
The prongs can also be intended to make contact with the tympanic membrane when in use. In one embodiment the flexible sealing part is configured to serve as a synthetic tympanic membrane by vibrating though the sound transmitted through the air filled tube. The prongs on the surface of the vibrating flexible sealing part can be used to transmit the vibrations directly on certain parts of the tympanic membrane.
The prongs may alternatively be used to get an estimate about the insertion. An insert procedure could thus follow these steps: firstly a tool (possibly the ear insert with prongs) is used to measure the minimum ear canal depth, by insertion till it touches the tympanic membrane; then the prongs are cut 2 mm shorter than the insertion depth measured; correct insertion is verified by use of 2 mm shorter cut off length and the dome size as information to a simulation of the residual volume in a software simulator—this allows to precisely calculate the required gain for a specific ear.
A further way of insertion depth measurement and verification, is to use a beep sound, which could be used to get a good modeling for the residual volume.
In another embodiment the distal end of the air filled tube is formed by a core frustum. Also the proximity of the distal end of the air filled tube can be part of the frustum. Preferably a core pathway of the frustum is permeable for sound transmission. The frustum can for example be a clipped cone, a clipped pyramid, a horn or a similar frustum form or have a form of the aforementioned frusta. The form of the core frustum preferably increases high frequency sound transmission from the air filled tube. The distal end of the air filled tube can also be formed as a cylindrical opening.
The flexible sealing part can have an asymmetric shape. Preferably the asymmetric shape is adapted to account for the skewness of the boundary between hard and soft tissue between the bony portion and a cartilaginous portion of the ear canal. The material of the flexible sealing part can partly or entirely be permeable for sound transmission, it can for example be a porous material, a grating, contain small holes or the like. The material of the flexible sealing part can also be permeable for gas and/or fluids.
The core pathway of the air filled tube can contain a wax filter element, which can block cerumen (ear wax) from entering the core pathway of the air filled tube. Preferably the wax filter element is a grating or similar means for blocking cerumen that is placed at the distal end of the air filled tube.
The air filled tube may be a thin tube such as a tube having an inner diameter of no more than 1.3 mm or nor more than 0.9 mm. These thin tubes are in-conspicuous, and well liked by the users however requires special sound processing by the sound signal processor of the hearing aid. The diminished air volume will help alleviate the problem of acoustic high frequency attenuation due to the relatively thin tubing, compared to traditional BTE tubing. The smaller volume will create more high frequency response, typically in the order of 10 dB for some frequencies, than for a traditional fitting anchored further out in the ear canal. The electronic amplification for high frequencies should therefore be reduced accordingly in order to obtain the same end result. This will result in that the audiological fitting range may be increased.
Another factor is that for a closed dome or similar, such as a bony seal, all the sound is passing through the hearing instrument, as there is little or no vent channel to pass directly from the sound source in the surrounding to the tympanic membrane, and therefore a higher time delay through the signal processing may be allowed without audible disturbances to the user. Such disturbances are usually perceived or measured as comb filter problems, and stems from interaction between sound passed through a vent and amplified sound. Without such a problem delay times of up to 10-12 milliseconds may be permitted.
The signal processing could therefore be optimized for increased fitting range taking less electronic high frequency amplification into account and permitting delay times up to 10-12 milliseconds.
The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings in which:
The air filled tube 26 and the flexible sealing part 38 can be of two different materials. Preferably the two different materials have different mechanical properties. The material of the air filled tube 26 is preferably more rigid than the material of the flexible sealing part 38. The first material can for example be PEBA (polyether block amide), PEBAX or similar TPE (thermoplastic elastomer) or TPU (thermoplastic polyurethane) materials. The second material can for example be TPE, silicone or the like. The material of the air filled tube 26 is preferably rigid enough as to allow for insertion of the air filled tube 26 into the ear canal 30 without the need of further means of insertion (not shown). The material of the air filled tube 26, however, is preferably also flexible enough to at least partly conform to the shape of the ear 14 and the ear canal 30, which allows the air filled tube 26 to be inserted into the ear canal 30 without hurting the wall of the ear canal 30. The two different materials for the air filled tube 26 and the flexible sealing part 38 can for example be cast in a two-shot molding process or an overmolding process.
The arrangement of the prongs 64 on the surface of the flexible sealing part 38 can be symmetric, asymmetric or random. Preferably the prongs 64 are closer to the center of the flexible sealing part 38 to avoid contact with the wall of the ear canal 30 during insertion of the air filled tube 26. The lengths of the prongs 64 can be identical for all prongs 64 or different. Preferably prongs 64 which are arranged closer to the center are longer than prongs 64 that are closer to the wall of the ear canal 30. The prongs 64 can have lengths between 0.1 mm and 10 mm, such as between 0.5 mm and 7.5 mm and preferably between 1 and 5 mm.
The prongs 64 can also contain means for producing an alarm sound or alarm signal when the prongs 64 get into contact with the tympanic membrane 48. For example the material can have piezoelectrical properties which lead to a current through the prongs 64 when the prongs 64 are deformed due to the contact with the tympanic membrane 48. The current through the prongs 64 can then be used to sound an alarm or send an electrical signal through a cable to the BTE unit 12, where an alarm sound can be generated by the receiver 22 and sent to the tympanic membrane 48 by the air filled tube 26 (not shown).
Alternatively the prongs 64 can also be in contact with the tympanic membrane 48 and guide vibrations generated at the distal end 40 of the air filled tube 26 to the tympanic membrane 48. In this case the distal end 40 of the air filled tube 26 is configured to convert sound into vibrations of the prongs 64, for example by a coupling element or by acting as a synthetic tympanic membrane (not shown).
| Number | Date | Country | Kind |
|---|---|---|---|
| 13181282.8 | Aug 2013 | EP | regional |
