EP1191815A2 - At least partially implantable hearing system with direct mechanical stimulation of a lymphatic space of the internal ear - Google Patents

Abstract

An at least partially implantable sensor for rehabilitation of a hearing disorder having at least one acoustic sensor for picking up acoustic sensor signals and converting the acoustic sensor signals into corresponding electrical audio sensor signals; an electronic signal processing unit for audio signal processing and amplification of the electric sensor signals; an electrical power supply unit which supplies individual components of the system with energy, and an actoric output arrangement for direct mechanical stimulation of a lymphatic inner ear space, wherein the actoric output arrangement has an intracochlear electromechanical transducer.

Description

The present invention relates to an at least partially implantable system for rehabilitation a hearing disorder with at least one sound-absorbing sensor (microphone), an electronic arrangement for audio signal processing and amplification, an electrical Power supply unit, which individual components of the system with electricity supplied, and an output-side actuator arrangement for direct mechanical Stimulation of a lymphatic space in the inner ear.

In the present case, the term “hearing impairment” is intended to combine all types of inner ear damage Inner and middle ear damage as well as occasional or permanent ear noises (Tinnitus) can be understood.

The rehabilitation of sensory hearing disorders with partially implantable electronic systems has become very important in recent years. This applies in particular to the Group of patients whose hearing is complete due to accident, illness or other influences has failed or is not functional from birth. In these cases, that's just it The inner ear (cochlea) and not the central neuronal auditory canal can be affected electrical stimulus signals which stimulate the remaining auditory nerve and thus produce an auditory impression that can lead to an open understanding of language. With these so-called Cochlear implants are inserted into the cochlea by a stimulus electrode array, designed by is controlled by an electronic system, this being hermetically sealed and biocompatible encapsulated electronics module surgically in the bony area behind the ear (mastoid) is embedded. However, the electronic system essentially only contains decoding and Driver circuits for the stimulation electrodes; the acoustic sound recording, the change of this Sound signal into electrical signals and their further processing is basically done externally in a so-called speech processor, which is worn on the outside of the body. The The speech processor encodes the preprocessed signals accordingly to a high frequency Carrier signal which is transmitted via an inductive coupling through the closed skin (transcutaneously) is transferred to the implant. The sound-picking microphone is without exception outside the body and in most applications in a one worn on the auricle Case of a behind-the-ear hearing aid (BTE) and it is connected to a cable connected to the speech processor. Such cochlear implant systems, their components and Principles of transcutaneous signal transmission are exemplified in US-A-5 070 535, US-A-4 441 210 and US-A-5 626 629. Language preparation procedures and Coding for cochlear implants are described, for example, in US Pat. No. 5,597,380, US Pat. No. 5,601,617 and US-A-5,603,726.

In addition to the rehabilitation of deaf or deaf patients with cochlear implants There have been approaches for some time now, patients with sensorineural hearing impairment, which cannot be remedied by surgery, with partially or fully implantable hearing aids to offer better rehabilitation than with conventional hearing aids. The principle is there in the predominant embodiments therein, an ossicle of the middle ear or the inner ear stimulate directly via a mechanical or hydromechanical stimulus and not via the amplified acoustic signal of a conventional hearing aid, in which the amplified sound signal is fed to the outer ear canal. The actuator stimulus of this Electromechanical systems are implemented using various physical transducer principles such as through electromagnetic and piezoelectric systems. The advantage this method is mainly improved in comparison to conventional hearing aids Sound quality and seen in the case of fully implanted systems in the invisibility of the hearing prosthesis. Such partially and fully implantable electromechanical hearing aids are exemplified by H. Leysieffer et al. "A fully implantable hearing aid for the hearing impaired: TICA LZ 3001 "ENT 46: 853-863 and H.P. Zenner et al." Totally implantable hearing device for sensorineural hearing loss ", The Lancet Vol. 352, No. 9142, page 1751 and in numerous patents, including US-A-5 360 388, US-A-5 772 575, US-A-5 814 095 and US-A-5 984 859.

Recently, such partially and fully implantable hearing systems for rehabilitation have become one Inner ear damage in clinical use. It shows up depending on the physical used Principle of the output-side electromechanical converter and in particular its Type of coupling to the ossicles of the middle ear that the results achieved improvement of language understanding can be very different. In addition, with some Sufficient volume level cannot be reached in patients; that aspect is spectrally very different, which can mean that for example medium and high Frequencies the loudness generated is sufficient, but not at low frequencies respectively vice versa. Furthermore, the transmissible spectral bandwidth can be limited for example with electromagnetic transducers at low and medium frequencies or at piezoelectric transducers to medium and high frequencies. Furthermore, you can nonlinear distortions that are particularly pronounced in electromagnetic transducers have a negative impact on the resulting sound quality. The lack of loudness leads in particular that the audiological indication area for the implantation of an electromechanical Hearing aid is very limited, which means patients for example with a sensorineural hearing loss greater than 50 dB HL (= hearing loss) in the Low frequency range with a piezoelectric system are insufficiently available. In contrast, pronounced high-frequency losses are difficult to supply with electromagnetic transducers.

Many patients with inner ear damage also suffer from intermittent or permanent ear noises (tinnitus), which cannot be remedied by surgery and against the up to today there are no approved drug treatments. Therefore, so-called Tinnitus maskers available; these are small, battery powered devices that are similar a hearing aid behind or in the ear and by artificial sound that over a hearing aid speaker, for example, is emitted into the ear canal, the tinnitus mask ("mask") in a psycho-acoustic way and the annoying ear noise lower it below the perception threshold as far as possible. The artificial sounds are often narrowband noises (for example third-octave noise), which in their spectral position and Volume levels can be adjusted via a programming device in order to achieve the best possible adjustment to enable the individual ear noise situation. Furthermore, has existed since recently the so-called "retraining method", whereby by the combination of a mental Training program and the performance of a broadband sound (noise) near the Hearing threshold, the perceptibility of tinnitus can also be largely suppressed should (H. Knör, "Tinnitus Retraining Therapy and Hearing Acoustics" magazine "Hearing Acoustics" 2/97, Pages 26 and 27). These devices are also referred to as "noisers".

In both of the above-mentioned methods for device therapy for tinnitus, hearing aid-like, to carry technical devices visible on the outside of the body in the ear area, which the Stigmatize wearers and therefore do not like to be worn.

In US-A-5 795 287 an implantable tinnitus masker with "direct drive" ("direct drive ") of the middle ear, for example, via an electromechanical coupling coupled to the ossicular chain Transducer described. This directly coupled converter can preferably be a so-called Floating Mass Transducer (FMT). This FMT corresponds to the converter for implantable hearing aids described in US-A-5,624,376.

In DE-C-198 58 398 and DE-A-198 59 171 implantable systems for treatment a tinnitus described by masking and / or noiser functions, in which the signal processing electronic path of a partially or fully implantable hearing system through appropriate electronic modules is supplemented in such a way that those for tinnitus masking or Noiserfunction necessary signals in the signal processing path of the hearing aid function fed in and the associated signal parameters by further electronic measures the pathological needs can be individually adjusted. This adaptability can be realized in that the necessary setting data of the signal generation and Feed electronics in the same physical and logical data storage area of the implant system stored and programmed in terms of hardware and software, and via appropriate electronic actuators, the supply of the masker or Control the noise signal in the audio path of the hearing implant.

The at least partially implantable hearing systems for rehabilitation described above an inner ear damage that is based on an output-side electromechanical transducer, differ essentially from conventional, conventional hearing aids only in that the acoustic stimulus on the output side (an amplified sound signal before the eardrum) through an increased mechanical stimulus of the middle or Inner ear is replaced. The acoustic stimulus of a conventional hearing aid leads finally about the mechanical excitation of the eardrum and the subsequent one Middle ear also to a vibratory, i.e. mechanical stimulus of the inner ear. In terms of the meaningful audio signal preprocessing is basically similar or same requirements. Furthermore, in both embodiments, ultimately on the output side, a locally located vibratory stimulus to the damaged inner ear guided (for example, increased mechanical vibration of the stirrup in the oval window of the inner ear).

In the case of deafness bordering on deafness are inadequate for the reasons mentioned The volume level of implantable, electromechanical systems cannot be used so far; here cochlear implants (CIs) with purely electrical stimulation of the inner ear are possible naturally no sound quality can be expected, for example an acceptable music transmission enabled, but primarily for the attainment or restoration a sufficient understanding of the language, if possible without lip reading. by virtue of The electrical irritation is accompanied by hearing loss that extends to complete deafness a spectrally wide audiological range possible.

With widespread damage to the middle ear, the so-called otosclerosis, in particular the mobility of the ligament of the stirrup suspension in the oval window Calcification processes are restricted or completely prevented by the surgical method stapedectomy uses a passive prosthesis that on the one hand is mostly fixed to the long anvil process by a bracket and on the other hand with its mostly circular shaft in an artificially made opening in the stirrup footplate is used. The stirrup can also be removed completely. The Vibrations of the eardrum are transferred to the anvil using the hammer and cause corresponding vibrations of the passive prosthesis, which lead to dynamic volume shifts in the perilymph of the inner ear, thus triggering traveling waves on the basilar membrane and ultimately lead to an auditory impression. This method has been very safe and successful worldwide for decades as a reconstructive middle ear surgery applied. The insertion of the opening in the stirrup footplate is done by fine surgical Instruments or achieved in particular by laser techniques.

For a short time it has been scientifically known from CI implantations that too in case of incomplete deafness CIs can be used successfully if with sufficient hearing discrimination is no longer achieved with a conventional hearing aid can be. Interestingly, it was demonstrated that the essential inner ear structures, that allow the acoustic residual hearing, partially or largely long-term stability can be obtained if a CI electrode is inserted into the cochlea (Ruh, S. et al .: "Cochlear implant for residual hearing", Laryngo-Rhino-Otol. 76 (1997), 347-350; Müller-Deile, J. et al .: "Cochlear implant care in non-deaf patients?", Laryngo-Rhino-Otol. 77: 136-143 (1998); Lehnhardt, E .: "Intracochlear placement of cochlear implant electrodes in soft surgery technique ", HNO 41 (1993), 356-359) it can be concluded that, as expected, further clinical and audiological Research in the foreseeable future clinically safe electrodes with residual hearing can be placed intracochlearly that the remaining inner ear structures are long-term stable are obtainable and thus also in a biologically adequate way, i.e. vibratory, are still stimulable and lead to a usable listening impression.

The older EP patent application 00 119 195.6 describes a hearing system with a plurality of electromechanical transducers arranged along the cochlea for excitation the fluid-filled inner ear spaces by forming a traveling wave configuration on the basilar membrane. The older EP patent application 01 109 191.5 discloses a hearing system with a dual intracochlear arrangement, which in combination a stimulator arrangement with at least one stimulator element for at least indirect mechanical Stimulation of the inner ear and an electrically acting stimulating electrode arrangement with at least one cochlear implant electrode for electrical stimulation of the Has inner ear. These hearing aids make relatively complicated surgical procedures necessary.

US-A-5 977 689 discloses a hearing system microactuator with an implantable device in the middle ear Hollow body described, which is filled with an incompressible liquid and in which at least one piezoelectric connected to a relatively large-area membrane Converter is housed. The interior of the hollow body is connected to a nozzle, which is used in an artificial fenestration of the promontory and which its end remote from the hollow body of one in comparison to the transducer membrane small membrane is complete. The converter will practice when using appropriate electrical signals is applied, force on the liquid in the hollow body , causing the small nozzle end membrane in contact with fluid in the inner ear of the micro actuator is deflected.

From US-A-5 772 575 and US-A-5 984 859 is a system of the type mentioned is known in which a microactuator with a flat flexible membrane is provided. The micro actuator membrane forms the end face a screw that is screwed into an artificial window in the promontory, or the microactuator is inserted directly into such a window in such a way that its flat membrane in the inner ear fluid contacted. According to another In one embodiment, the microactuator sits in the shaft of a passive stapedectomy prosthesis of the type discussed above, for combined passive and active stimulation to care.

The invention has for its object an at least partially implantable system for the rehabilitation of a hearing impairment that is capable of improving To provide rehabilitation for sensory hearing disorders.

This object is achieved in that at least partially implantable System for the rehabilitation of a hearing disorder with at least one sound-absorbing sensor (Microphone), an electronic arrangement for audio signal processing and amplification, an electrical power supply unit, which individual components of the system with Power supply, and an output-side actuator arrangement for direct mechanical Stimulation of a lymphatic space of the inner ear, according to the invention the output side actuator arrangement consists of an intracochlear electromechanical transducer.

The main advantages of an intracochlear transducer structure according to the invention exist on the one hand in particular that the mechanical stimulus directly in the inner ear has a relatively large area can be generated and no additional masses, rigidity of the suspension and / or lossy joints of the middle ear crossbones in the mechanical transmission path lie, in particular to linear distortions of the frequency response of the Can lead converter. On the other hand, it can be assumed that the direct Inner ear stimulation the inter-individual reproducibility of the mechanical stimulation is significantly better than in the case of transmission through coupling elements to the middle ear crossbones because therefore always anatomical fluctuations and especially the personal approach of the surgeon play an important role.

Another advantage of the present invention is that a direct, electromechanical stimulation of the cochlea the occurrence of feedback (coupling of the output signal into the sensor / microphone) as expected largely reduced is because the ossicle chain and thus the eardrum is not or clearly is reduced to vibrations. This is particularly advantageous if a sound sensor (microphone function) is applied in the immediate vicinity of the eardrum (DE-C-196 38 158 and US-A-5 999 632).

The electromechanical transducer used here preferably works according to the Principle of dynamic volume change due to dynamic surface enlargement or reduction according to the electrical, controlling Converter AC signal. An optimal effect of the transducer of the present invention can be achieved as expected, if by constructive measures It is ensured that the entire surface of the intracochlear transducer is as possible vibrates (ideally ball oscillator) because this results in a maximum volume shift and therefore the highest possible stimulation level for a given electrical drive power of the Converter is achieved by the preprocessing electronics system.

The operative access for the intracochlear transducer is preferably through the oval or an artificial cochlear window, for example a promontorial window. After this, as described above, the stapedectomy with an opening in the Stirrup footplate has long proven itself to be a safe middle ear surgery be assumed that such an opening and thus direct access to the inner ear is also possible without an increased risk of damage if there is no otosclerosis and the footplate is still fully moveable, i.e. if you have pure inner hearing loss. This means that the proven surgical techniques of stapedectomy are transferable in the present case for the transducer implantation.

The intracochlear transducer is advantageous at the end of a flexible support structure, in particular a polymer support structure.

Basically, all physical transducer principles can be considered, such as electromagnetic, electrodynamic, piezoelectric, dielectric (capacitive) and magnetostrictive. Especially the piezoelectric principle is preferred here, since with a simple transducer design Ideally, the surface vibrator can be most easily met. In particular can the intracochlear transducer, preferably with the use of geometric Shape transformations, in particular the bimorph principle, the unimorph principle or of the heteromorph principle with passive material partners, so that it is given Transducer voltage a maximum volume change with minimal electrical Power consumption generated.

The intracochlear transducer is particularly easy to manufacture and can be easily implanted, if it has a piezoelectric tube section with a cylindrical cross section, whose inner and outer peripheral surface with a surface metallization Formation of electrical transducer electrodes is provided.

The intracochlear piezoelectric transducer can be based on lead zirconate titanate (PZT). Single-layer or multi-layer windings thinner are also particularly suitable Polyvinylidene fluoride film (PVDF). The transducer element is expedient with a biocompatible one Sheathing preferably made of an elastic polymer, for example silicone. The entire transducer element can be surrounded by the biocompatible casing his. According to a modified embodiment, the casing has at least one opening - and preferably at least two openings at the lower end of the pipe as well as in the upper area of the casing - for the entry and exit of intracochlear Lymph on. Which is (are) designed such that a dynamic change in radius of the Transducer directly a lymphatic shift and thus an intracochlear volume shift is achieved. In particular, the tube surface of the intracochlear transducer and the cross-sectional area of the inlet and outlet openings can be designed so that a hydraulic Transformation is achieved, which leads to higher rapids of the lymph and thus to higher ones Stimulation levels of the cochlea result from direct surface change through the Converter itself.

As known per se from US-A-5 277 694, the converter is preferably designed to be highly tuned, that is, the first mechanical resonance frequency lies at the upper spectral end of the Transmission range. This means that the frequency response when voltage is applied to one Example of a piezoelectric transducer and thus largely free of linear distortions. The intracochlear transducer can expediently have a transmission range of approximately 100 Hz to about 10 kHz.

In a further embodiment of the invention, a mechanical damping element can be provided be the vibrations of the intracochlear transducer from a transducer lead decoupled, so as to cause at least partial resonance of the middle ear crossbones to prevent or mechanical contact with this transducer lead largely reduce. Such a resonance could otherwise occur Using sensors close to the eardrum (microphones) can lead to disturbing feedback.

The material of the damping element has a similar cross-sectional geometry to that of the Carrier preferably chosen so that a large one to achieve high damping values there is a mechanical impedance difference to the carrier material.

The intracochlear transducer can expediently be designed for volume changes of approximately 2 × 10 ^-4 microliters. The overall diameter of the intracochlear transducer arrangement can advantageously be in the range from 0.2 mm to 2.0 mm, and the immersion depth of the intracochlear transducer and the length of its active transducer element can preferably be between 0.3 and 2 mm.

According to a further embodiment of the present invention is a digital signal processor provided that performs the audio signal processing and processing and / or generated digital signals for tinnitus masking.

The signal processor can be designed statically in such a way that corresponding software modules based on scientific knowledge, once in a program memory of the signal processor are stored and remain unchanged. But then lie later for example, improved algorithms based on recent scientific knowledge for speech signal processing and processing and if these are to be used, must the entire implant or the implant module through an invasive, operative patient intervention, that contains the corresponding signal processing unit against a new one with the changed operating software. This intervention harbors new medical Risks for the patient and involves a lot of effort. This problem can be countered by the fact that in a further embodiment of the invention one, preferably PC-based, telemetry device for transmitting data between an implanted Part of the system and an external unit, especially an external programming system, is provided, and that the signal processor for recording and playback an operating program, a repeatable, implantable memory arrangement is assigned, with at least parts of the operating program by the external Unit changed or exchanged data transmitted via the telemetry device can be. This way, after implantation of the implantable system the operating software, including software for controlling the intracochlear Converter, as such change or even completely replace this makes it possible further scientific knowledge, for example regarding speech signal processing strategies to implement in the implant without the implant having to be operated Intervention must be replaced.

The design is preferably such that, in addition, fully implantable Systems also in a manner known per se, that is to say patient-specific Data, such as audiological adaptation data, or changeable implant system parameters (For example as a variable in a software program to control the intracochlear transducer or to regulate battery recharge) after the implantation transcutaneously, i.e. wirelessly through the closed skin, transferred into the implant and can be changed with it. The software modules are preferably dynamic, or in other words capable of learning, designed to achieve the best possible rehabilitation of the particular hearing disorder. In particular, the software modules be designed adaptively, and a parameter adjustment can be made by "training" by the Implant carriers and other aids are made.

Furthermore, the signal processing electronics can contain a software module that a optimal stimulation achieved based on an adaptive neural network. This neural network can be trained by the implant carrier and / or with the help of other external aids.

The memory arrangement for storing operating parameters and the memory arrangement for recording and playback of the operating program can be independent of each other Memory implemented; however, it can also be a single memory act in which both operating parameters and operating programs are stored can.

The present solution allows the system to be adapted to conditions that are not yet are detectable after implantation of the implantable system. For example, at an at least partially implantable hearing system for the rehabilitation of a monaural or binaural inner ear disorder and tinnitus with mechanical stimulation of the Inner ear the sensory (sound sensor or microphone) and actuator (intracochlear transducer) biological interfaces always dependent on the anatomical, biological and neurophysiological conditions, for example of the interindividual healing process. These interface parameters can be customized in particular also be time variant. For example, the transmission behavior of a implanted microphones due to tissue layers and the transmission behavior of the intracochlear electromechanical transducer coupled to the inner ear vary the coupling quality individually and individually. Such Differences in the interface parameters that are known from those known from the prior art Do not diminish devices even by replacing the implant or can be eliminated in the present case by change or Improvement of the signal processing of the implant can be optimized.

• Sprachanalyseverfahren (zum Beispiel Optimierung einer Fast-Fourier-Transformation (FFT)),
• statische oder adaptive Störschallerkennungsverfahren,
• statische oder adaptive Störschallunterdrückungsverfahren,
• Verfahren zur Optimierung des systeminternen Signal-Rauschabstandes,
• optimierte Signalverarbeitungsstrategien bei progredienter Hörstörung,
• ausgangspegelbegrenzende Verfahren zum Schutz des Patienten bei Implantatfehlfunktionen beziehungsweise externen Fehlprogrammierungen,
• Verfahren zur Vorverarbeitung mehrerer Sensor-(Mikrofon-)signale, insbesondere bei binauraler Positionierung der Sensoren,
• Verfahren zur binauralen Verarbeitung zweier oder mehrerer Sensorsignale bei binauraler Sensorpositionierung, zum Beispiel Optimierung des räumlichen Hörens beziehungsweise Raumorientierung,
• Phasen- beziehungsweise Gruppenlaufzeit-Optimierung bei binauraler Signalverarbeitung,
• Verfahren zur optimierten Ansteuerung der Ausgangsstimulatoren, insbesondere bei binauraler Positionierung der Stimulatoren.

With an at least partially implantable hearing system, it may be useful or necessary to implement improved signal processing algorithms after implantation. The following are particularly worth mentioning:

• Speech analysis method (e.g. optimization of a Fast Fourier Transform (FFT)),
• static or adaptive noise detection methods,
• static or adaptive noise suppression methods,
• Process for optimizing the system-internal signal-to-noise ratio,
• optimized signal processing strategies for progressive hearing impairment,
• output level limiting procedures to protect the patient in the event of implant malfunctions or external incorrect programming,
• Method for preprocessing several sensor (microphone) signals, especially with binaural positioning of the sensors,
• Method for binaural processing of two or more sensor signals with binaural sensor positioning, for example optimization of spatial hearing or spatial orientation,
• Phase or group delay optimization in binaural signal processing,
• Process for the optimized control of the output stimulators, especially with binaural positioning of the stimulators

• Verfahren zur Optimierung des Betriebsverhaltens des intracochleären Ausgangswandlers (zum Beispiel Frequenz- und Phasengangoptimierung, Verbesserung des Impulsübertragungsverhaltens),
• Sprachsignal-Kompressionsverfahren bei Innenohrschwerhörigkeiten,
• Signalverarbeitungsmethoden zur Recruitment-Kompensation bei Innenohrschwerhörigkeiten.

With the present system, the following signal processing algorithms can also be implemented after the implantation:

• Methods for optimizing the operating behavior of the intracochlear output converter (e.g. frequency and phase response optimization, improving the pulse transmission behavior),
• Speech signal compression method for inner ear deafness,
• Signal processing methods for recruitment compensation for inner ear hearing loss.

Furthermore, in implant systems with a secondary energy supply unit, that means a rechargeable battery system, but also in systems with primary Battery supply assume that these electrical energy storage devices are progressing Technology ever longer lifetimes and thus increasing residence times enable in the patient. It can be assumed that basic and application research advances rapidly for signal processing algorithms. The need or the patient's wish to adapt or change the operating software is therefore expected to expire before the life of the implant-internal energy source enter. The system described here permits such an adaptation of the Operating programs of the implant also in the already implanted state.

Preferably, an intermediate storage arrangement is also provided, in which of the data transmitted to the external unit via the telemetry device before being forwarded to the signal processor can be cached. In this way, the Complete the transfer process from the external device to the implanted system, before the data transmitted via the telemetry device is forwarded to the signal processor become.

Furthermore, a check logic can be provided in the buffer arrangement stored data before being passed to the signal processor of a review subjects. A microprocessor module, in particular a microcontroller, be provided for controlling the signal processor within the implant via a data bus, expediently the checking logic and the buffer arrangement in the Microprocessor module are implemented and with the data bus and the telemetry device also program parts or entire software modules between the outside world, the microprocessor module and the signal processor can be transmitted.

The microprocessor module is preferably an implantable memory arrangement for Save a work program for the microprocessor module assigned, and at least Parts of the work program for the microprocessor module can be carried out by the External unit changed or exchanged data transmitted via the telemetry device become.

In a further embodiment of the invention, at least two memory areas can be used Recording and playback of at least the operating program of the signal processor is provided his. This contributes to the reliability of the system by the multiple Presence of the memory area which contains the operating program or programs contains, for example after a transfer from external or when switching on the The software can be checked for errors.

Analogously to this, the buffer arrangement can also have at least two memory areas for recording and playback from the external unit via the telemetry device have transmitted data, so that after data transmission from the external Unit still in the area of the buffer a check of correctness of the transmitted data can be made. The memory areas can, for example complementary storage of the data transmitted by the external unit his. At least one of the storage areas of the intermediate storage arrangement can but also for recording only part of the data transmitted by the external unit be designed, in which case the verification of the correctness of the transmitted Data in sections.

To ensure that a new transmission process is started in the event of transmission errors can be, the signal processor can also be a preprogrammed, not rewritable permanent storage area can be assigned in which the for a "minimal operation" instructions and parameters required by the system are stored, for example Instructions that are at least error-free after a "system crash" Operation of the telemetry device for receiving an operating program and instructions to store the same in the control logic.

As already mentioned, the telemetry device is advantageously except for reception of operating programs from the external unit also for the transmission of operating parameters between the implantable part of the system and the external unit designed so that on the one hand such parameters from a doctor, a hearing care professional or can be adjusted to the wearer of the system itself (for example volume), on the other hand, the system can also transmit parameters to the external unit, for example to check the status of the system.

A fully implantable hearing system of the type explained here can be on the implant side in addition to the intracochlear converter and the signal processing unit at least have an implantable sound sensor and a rechargeable electrical storage element, in such a case, preferably a wireless, transcutaneous charging device is provided for loading the memory element. However, it is understood that for energy supply a primary cell or another energy supply unit is also available can be that does not require transcutaneous reloading. This is especially true if you take into account that in the near future mainly through further development of processor technology with a substantial reduction in the energy requirement for electronic signal processing is to be expected, so that new forms of energy supply for implantable hearing systems become practically applicable, for example an energy supply using the Seebeck effect, as described in DE-C 198 27 898. A wireless is also preferred Remote control for controlling the implant functions by the implant carrier is available.

If the hearing system is partially implantable, at least one sound sensor is the electronic signal processing unit, the power supply unit and a modulator / transmitter unit in an external on the body, preferably on the head above the implant, external module to be carried. The implant has the electromechanical, intracochlear converter, but is energetically passive and receives its operating energy and control data for the intracochlear converter via the modulator / transmitter unit in the external module.

The system described can with fully implantable design as well as with partially implantable The structure should be monaural or binaural. A binaural system for Rehabilitation of a hearing disorder of both ears has two system units, each are assigned to one of the two ears. The two system units can each other be essentially the same. But it can also be a system unit as a master unit and the other system unit is designed as a slave unit controlled by the master unit his. The signal processing modules of the two system units can be set to any Way, in particular via a wired implantable line connection or via a wireless connection, preferably a bidirectional radio frequency link, a structure-borne ultrasound system or electrical conductivity of the tissue of the implant carrier utilizing data transmission path, so with each other communicate that optimized binaural signal processing in both system units and converter array control is achieved.

FIG. 1

schematisch einen Schnitt durch einen Teil des menschliches Mittelohres mit implantiertem intracochleärem Wandler,

FIG. 2

schematisch den prinzipiellen Aufbau des intracochleären Wandlers gemäß FIG. 1,

FIG. 3

einen Schnitt entlang der Linie III-III der FIG. 4 für eine abgewandelte Ausführungsform des intracochleären Wandlers gemäß FIG. 1,

FIG. 4

eine Seitenansicht des intracochleären Wandlers gemäß FIG. 3,

FIG. 5

ein Blockschaltbild eines vollimplantierbaren Hörsystems zur Rehabilitation einer Mittel- und/oder Innenohrstörung und/oder eines Tinnitus,

FIG. 6

ein vollimplantierbares Hörsystem gemäß vorliegender Erfindung sowie

FIG. 7

ein teilimplantierbares Hörsystem gemäß vorliegender Erfindung.

Preferred exemplary embodiments of the hearing system according to the invention or possible partial and fully implantable overall systems are described in more detail below with reference to the accompanying drawings. Show it:

FIG. 1

schematically a section through part of the human middle ear with an implanted intracochlear transducer,

FIG. 2

schematically the basic structure of the intracochlear converter according to FIG. 1,

FIG. 3

a section along the line III-III of FIG. 4 for a modified embodiment of the intracochlear converter according to FIG. 1,

FIG. 4

a side view of the intracochlear transducer according to FIG. 3,

FIG. 5

2 shows a block diagram of a fully implantable hearing system for the rehabilitation of a middle and / or inner ear disorder and / or tinnitus,

FIG. 6

a fully implantable hearing system according to the present invention as well

FIG. 7

a partially implantable hearing system according to the present invention.

FIG. 1 schematically shows a section through part of the human middle ear the long anvil process 10, the stirrup with the footplate shown perforated here 11, the stirrup superstructure (leg 12 and small head 13) and the ligament 14, with which the stirrup is hung in the oval window of the bony cochlear wall 15 is.

Through the perforation of the stirrup foot plate 11 there is an intracochlear one in the inner ear electromechanical transducer 18, 18 'introduced as a whole. The in FIG. 1 dashed Vibrations of the transducer 18, 18 'shown lead to dynamic volume shifts the perilymph 19 in the scala tympani of the inner ear. The converter 18, 18 'is on an implant feed line 20 is connected, the inside of which is shown in FIG. 2 shown electrical Converter leads 21 leads. The operative sealing of the implant feed line 20 in the Stirrup footplate perforation is expedient, as is known from stapes prosthetics, by rearrangement with fascia or other body-own thin tissue 23. The line 20 can be made with a deformable and preferably metallic one known from stapes prosthetics Hook or a loop 25 are fixed to the long anvil extension 10. in principle are the implant feed line 20 and the attachment of the transducer 18, 18 'to the distal one End of this line constructed as in the case of an intracochlear cochlear implant electrode. That is, at the distal end of the implant lead 20 there is a mechanical support 26 attached to the converter 18, 18 '. This carrier preferably consists essentially of a flexible polymer (preferably silicone) molded part of preferably circular Cross-section.

Furthermore, a mechanical damping element 28 can be provided, which the vibrations of the converter 18, 18 'decoupled from the feed line 20 and thus a transmission of the Avoid or at least reduce transducer vibrations on the middle ear Use a local sound sensor (microphone) of the implantable hearing system could lead to unwanted feedback.

The electromechanical converter 18, 18 'preferably works on the principle of dynamic volume change due to a dynamic surface enlargement or reduction in accordance with the electrical, driving converter alternating voltage signal. The required volume changes for an adequate, equivalent sound pressure level of approx. 100 dB SPL result in approx. 2 · 10 ^-4 microliters. The overall diameter of the transducer arrangement is in the range from 0.2 mm to 2.0 mm. The immersion depth of the transducer is in the range of 0.3 to 2 mm, the length of the active transducer element in the same range.

FIG. 2 schematically shows the basic structure of the converter 18 when using a Piezoelectric tube section 30 with a cylindrical cross section, preferably made of Lead zirconate titanate (PZT). It is on the inner and outer peripheral surface of the Pipe section 30 applied a surface metallization, which electrical transducer electrodes 31 and 32 forms. The converter can preferably also be a single or multilayer wrap of thin polyvinylidene fluoride film (PVDF). The material the surface metallization consists of biocompatible metal, preferably pure Gold, platinum, platinum-iridium, titanium, tantalum, stainless steels and their biocompatible alloys. The electrical connections of the converter electrodes 31 and 32 are made via the two transformer leads 21. The same selection applies to the material of the leads as for the metallization of the transducer.

When an alternating electrical voltage is applied to the piezoelectric tube section 30 there is a corresponding dynamic change in radius that corresponds to the dynamic described Volume shift in the intracochlear fluid results. The entire Transducer element 30, 31, 32 in this embodiment is preferably biocompatible thin sheath 33 surrounded. The casing 33 preferably consists of an elastic polymer such as silicone, which can be used as a carrier material for cochlear implant electrodes has proven to be excellent.

The FIGN. 3 and 4 schematically show a modified embodiment of the converter according to FIG. 2. In this case, transducer 18 'is not completely clear of the polymer jacket 33 surrounded. Rather, at the open lower end 35 of the pipe section 30 and one connected to the interior 36 of the pipe section 30 Transverse opening 37 in the upper region of the casing 33 for the entry and exit of intracochlear Lymph in or out of the tube interior 36 possible, as in FIG. 3 is indicated by arrows 39 and 40. Due to the dynamic change in radius of the Transducers 18 'therefore become a lymphatic shift and thus an intracochlear one Volume shift reached. With an appropriate design of the pipe surface of the Converter and the cross-sectional area of the inlet and outlet openings 35, 37 can according to the hydraulic principle a transformation can be achieved, which leads to higher speeds of the Lymph and thus leads to higher stimulation levels of the cochlea than through the direct one Surface change caused by the transducer itself.

FIG. 5 shows the possible structure of a signal-processing electronic module 41 of the at least partially implantable hearing system according to the present invention. One or more microphones 42 record the sound signal and convert it into corresponding electrical signals. These sensor signals are each selected in a unit 43, preprocessed and converted from analog to digital (A / D). The preprocessing can consist, for example, of an analog linear or non-linear pre-amplification and filtering (for example antialiasing filtering). The digitized sensor signal or signals are fed to a digital signal processor (DSP) 44, which performs the intended function of the hearing implant, such as audio signal processing in a system for inner ear deafness and / or signal generation in the case of a tinnitus masker or noiser. The signal processor 44 contains a non-rewritable permanent memory area S ₀ , in which the instructions and parameters required for "minimal operation" of the system are stored, and a memory area S ₁ , in which the operating software for the intended function or functions of the implant system are stored. This memory area is preferably duplicated (S ₁ and S ₂ ). The program memory, which can be written repeatedly, for accommodating the operating software can be based on EEPROM or RAM cells, in which case it should be ensured that this RAM area is always "buffered" by the energy supply system.

The digital output signals of the signal processor 44 are in a digital-to-analog converter (D / A) - and driver unit 45 converted into analog signals and to the for control of the converter 18, 18 'brought the desired level. This unit 45 can under Circumstances are completely eliminated, for example when using an electromagnetic intracochlear output transducer, for example a pulse width modulated, serial digital Output signal of the signal processor 44 transmitted directly to the output converter becomes.

In the case of FIG. 5 embodiment, the signal processing components 43, 44 and 45 are controlled by a microcontroller 47 (.mu.C) with one or two associated memories S ₄ and S ₅ via a bidirectional data bus 48. In particular, the operating software components of the implant management system, for example administrative monitoring and telemetry functions, can be stored in the memory areas S ₄ and S ₅ . The memory S ₁ and / or S ₂ can also be used to store externally changeable, patient-specific, for example audiological, adaptation parameters. Furthermore, the microcontroller 47 has a memory S _{3 that can be written} to repeatedly, in which a work program for the microcontroller 47 is stored.

In the implantable embodiment shown, the microcontroller 47 communicates with a telemetry system (TS) 50 via a data bus 49. This telemetry system 50 in turn communicates wirelessly bidirectionally with an external programming system (PS) 52 through the closed skin indicated at 51, for example via an inductive coil coupling (not shown) The programming system 52 can advantageously be a PC-based system with corresponding programming, processing, presentation and management software. The operating software of the implant system that is to be changed or completely exchanged is transmitted via this telemetry interface and initially stored temporarily in the memory area S ₄ and / or S _{5 of} the microcontroller 47. For example, the memory area S _{5 can be used} for a complementary storage of the data transmitted by the external system, and a simple verification of the software transmission by a read operation via the telemetry interface can be carried out to determine the coincidence of the contents of the memory areas S ₄ and S ₅ to check before the content of the rewritable memory S _{3 is} changed or exchanged.

According to the nomenclature used here, the operating software of the at least partially implantable hearing system should include both the operating software of the microcontroller 47 (for example housekeeping functions, such as energy management or telemetry functions) and the operating software of the digital signal processor 44. For example, a simple verification of the software transmission can be carried out by means of a reading process via the telemetry interface before the operating software or the corresponding signal processing components of this software are transmitted to the program memory area S _{1 of} the digital signal processor 44 via the data bus 48. Furthermore, the work program for the microcontroller 47, which is stored, for example, in the repeatedly writable memory S ₃ , can be changed or exchanged in whole or in part using the external unit 52 via the telemetry interface 50.

All electronic components of the implant system are made by a primary or secondary battery 30 supplied with electrical operating energy.

FIG. 6 schematically shows the structure of a fully implantable hearing system an intracochlear transducer 18 or 18 'according to FIGN. 1 to 4 and an implantable Microphone 42. A wireless remote control 54 is used to control the implant functions through the implant carrier. There is also a charging system with a charger 55 for wireless transcutaneous recharging of a secondary battery in the implant to power the hearing system, for example the battery 53 in FIG. 5, provided.

The microphone 42 can advantageously be constructed in the manner known from US Pat. No. 5,814,095 and with a microphone capsule, which is hermetically sealed on all sides in a housing is, as well as with an electrical bushing arrangement for bushing at least an electrical connection from the interior of the housing to the outside be provided, the housing having at least two legs, which in one Angles are aligned with respect to each other, one leg of the microphone capsule picks up and is provided with a sound entry membrane, the other leg contains the electrical bushing arrangement and opposite the plane of the sound entry membrane is set back, and the geometry of the microphone housing is chosen in this way is that when the microphone is implanted in the mastoid cavity of the sound entry membrane containing legs from the mastoid into an artificial hole in the back, protrudes into the bony ear canal wall and the sound entry membrane covers the skin of the ear canal wall touched. A fixation element can expediently be used to fix the microphone 40 of the type known from US-A-5 999 632, which has a cuff, the one with a cylindrical housing part containing the sound inlet membrane Thighs encloses and with against the side of the ear canal wall facing the ear canal skin projectable, projecting, elastic flange parts is provided. Includes the fixation element is preferably a holder, which said flange parts before the implantation against an elastic restoring force of the flange parts in a Push through the bend in the bent position of the ear canal wall holds.

The charging system also includes one connected to the output of the charger 55 Charging coil 56, which is preferably part of a transmission series resonant circuit, as is known from US-A-5 279 292 forms that with an unillustrated receive series resonant circuit can be coupled inductively. The reception series resonance circuit can with the Embodiment according to FIG. 6 be part of the electronics module 41 and accordingly US-A-5 279 292 form a constant current source for battery 53 (FIG. 5). Here lies the receiving series resonance circuit in a battery charging circuit, which is dependent from the respective phase of the charging current flowing in the charging circuit via one or the other branch of a full-wave rectifier bridge is closed.

The electronics module 41 is in the arrangement according to FIG. 6 via a microphone line 58 the microphone 42 and via the implant lead 20 to the intracochlear transducer 18 or 18 'connected.

FIG. 7 schematically shows the structure of a partially implantable hearing system with an intracochlear Transducers 18 and 18 'according to FIGN. 1 to 4. With this semi-implantable System are a microphone 42, an electronic module 62 for an electronic Signal processing largely according to FIG. 5 (but without the telemetry system 50), the energy supply 53 and a modulator / transmitter unit 63 in an external device on the body, external module 64 to be worn, preferably on the head above the implant. As with known partial implants, the implant is energetically passive. His electronics module 65 (without battery 53) receives its operating energy and converter control data the modulator / transmitter unit 63 in the external part 64.

Both the fully implantable and the partially implantable hearing system can be monoaural or be designed binaural. A binaural hearing aid rehabilitation system Both ears have two system units, each assigned to one of the two ears are. The two system units can be essentially the same. It can also be a system unit as a master unit and the other system unit as slave unit controlled by the master unit. The signal processing modules of the two system units can in any way, in particular via one wired implantable line connection or via a wireless connection, preferably a bidirectional radio-frequency link, a structure-borne ultrasound link or one that takes advantage of the electrical conductivity of the tissue of the implant carrier Data transmission link, so communicate with each other in both system units optimized binaural signal processing is achieved.

• Beide Elektronikmodule können jeweils einen digitalen Signalprozessor gemäß vorstehender Beschreibung enthalten, wobei die Betriebssoftware beider Prozessoren wie beschrieben transkutan veränderbar ist. Dann sorgt die Verbindung beider Module im wesentlichen für den Datenaustausch zur optimierten binauralen Signalverarbeitung zum Beispiel der Sensorsignale.
• Nur ein Modul enthält den beschriebenen digitalen Signalprozessor, wobei dann die Modulverbindung neben der Sensordatenübertragung zur binauralen Schallanalyse und -verrechnung auch für die Ausgangsignalübermittlung zu dem kontralateralen Wandler sorgt, wobei in dem kontralateralen Modul der elektronische Wandlertreiber untergebracht sein kann. In diesem Fall ist die Betriebssoftware des gesamten binauralen Systems nur in einem Modul abgelegt und wird auch nur dort transkutan über eine nur einseitig vorhandene Telemetrieeinheit von extern verändert. In diesem Fall kann auch die energetische Versorgung des gesamten binauralen Systems in nur einem Elektronikmodul untergebracht sein, wobei die energetische Versorgung des kontralateralen Moduls drahtgebunden oder drahtlos geschieht.

The following combination options are available:

• Both electronic modules can each contain a digital signal processor as described above, the operating software of both processors being transcutaneously changeable as described. Then the connection between the two modules essentially ensures data exchange for optimized binaural signal processing, for example of the sensor signals.
• Only one module contains the described digital signal processor, in which case the module connection, in addition to the sensor data transmission for binaural sound analysis and calculation, also provides for the output signal transmission to the contralateral converter, wherein the electronic converter driver can be accommodated in the contralateral module. In this case, the operating software of the entire binaural system is only stored in one module and is only changed transcutaneously there externally via a telemetry unit that is only available on one side. In this case, the energy supply for the entire binaural system can also be accommodated in only one electronic module, the energy supply for the contralateral module taking place in a wired or wireless manner.

Claims (21)

At least partially implantable system for the rehabilitation of a hearing disorder with at least one sound-absorbing sensor (microphone) (42), an electronic arrangement (41; 62, 65) for audio signal processing and amplification, an electrical energy supply unit (53) which supplies individual components of the system with electricity supplied, and an output-side actuator arrangement for direct mechanical stimulation of a lymphatic space of the inner ear, characterized in that the output-side actuator arrangement consists of an intracochlear electromechanical transducer (18, 18 '). Hearing system according to claim 1, characterized in that the intracochlear electromechanical transducer (18, 18 ') operates according to the principle of dynamic volume change due to a dynamic surface enlargement or reduction in accordance with the electrical, driving transducer alternating voltage signal. Hearing system according to claim 1 or 2, characterized in that the intracochlear transducer (18, 18 ') is designed such that at least the larger part of its surface vibrates. Hearing system according to claim 3, characterized in that the intracochlear transducer (18, 18 ') is designed to approximate a spherical oscillator. Hearing system according to one of the preceding claims, characterized in that the intracochlear transducer (18, 18 ') is designed for operative access through the oval or an artificial cochlear window, for example a promontory window. Hearing system according to one of the preceding claims, characterized in that the intracochlear transducer (18, 18 ') is arranged at the end of a flexible carrier (26), in particular a polymer carrier. Hearing system according to one of the preceding claims, characterized in that the intracochlear transducer (18, 18 ') is designed as a piezoelectric electromechanical transducer. Hearing system according to claim 7, characterized in that the intracochlear transducer (18, 18 ') has a piezoelectric tube section (30) with a cylindrical cross section, the inner and outer circumferential surface of which is provided with a surface metallization to form electrical transducer electrodes (31, 32). Hearing system according to one of the preceding claims, characterized in that the intracochlear transducer (18, 18 ') has an active transducer element (30, 31, 32) and at least this transducer element with a biocompatible casing (33), in particular made of an elastic polymer, for Example silicone, is provided. Hearing system according to claim 9, characterized in that at least one opening (35, 37) for the entry and exit of intracochlear lymph is formed in the casing (33) in such a way that a lymphatic shift is directly caused by a dynamic change in the radius of the transducer (18 ') and thus an intracochlear volume shift is achieved. Hearing system according to claims 8 and 10, characterized in that openings (35, 37) are provided at the lower end of the tube and in the upper region of the casing (33). Hearing system according to claim 11, characterized in that the tube surface of the intracochlear transducer (18 ') and the cross-sectional area of the inlet and outlet openings (35, 37) are designed such that a hydraulic transformation is achieved which leads to higher speeds of the lymph and thus leads to higher stimulation levels of the cochlea than through direct surface changes by the transducer itself. Hearing system according to one of the preceding claims, characterized in that the intracochlear transducer (18, 18 ') is tuned in such a way that its first mechanical resonance frequency lies at the upper spectral end of the transmission range. Hearing system according to one of the preceding claims, characterized in that a mechanical damping element (28) is provided which decouples the vibrations of the intracochlear transducer (18, 18 ') from the transducer feed line (20). Hearing system according to claims 6 and 14, characterized in that the material of the damping element (28) with a cross-sectional geometry similar to that of the support (26) is selected such that there is a large mechanical impedance difference to the support material in order to achieve high attenuation values. Hearing system according to one of the preceding claims, characterized in that a digital signal processor (44) is provided for the audio signal processing and processing and / or for generating digital signals for tinnitus masking. Hearing system according to claim 16, characterized by a, preferably PC-based, telemetry device (50) for transmitting data between an implanted part (41) of the system and an external unit (52), in particular an external programming system. System according to claim 16 or 17, characterized in that the signal processor (44) for recording and reproducing an operating program is assigned a repeatable, implantable memory arrangement (S ₁ , S ₂ ), and at least parts of the operating program by the external unit (52 ) Data transmitted via the telemetry device (50) can be changed or exchanged. System according to Claim 18, characterized in that a buffer arrangement (S ₄ , S ₅ ) is also provided, in which data transmitted by the external unit (52) via the telemetry device (50) are buffered before being forwarded to the signal processor (44) can, and preferably a check logic (47) is provided in order to subject data stored in the buffer arrangement (S ₄ , S ₅ ) to a check before forwarding them to the signal processor (44). System according to claim 19, characterized by a microprocessor module (47) for controlling the arrangement (43, 44, 45) for the audio signal processing and processing and / or for generating digital signals for tinnitus masking. System according to claim 20, characterized in that the microprocessor module (47) is assigned an implantable memory arrangement (S3) for storing a work program for the microprocessor module, and at least parts of the work program for the microprocessor module by the external unit (52) via the telemetry device ( 50) transmitted data can be changed or exchanged.

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