EP1181950B1 - Implantable hearing system having means for measuring the coupling quality - Google Patents

Abstract

The system has at least one sensor for picking up sound signals and converting them into electrical signals, an electronic unit for audio signal processing and amplification, an electrical supply unit and at least one electromechanical output converter for mechanical stimulation of the middle and/or inner ear. An impedance measurement arrangement determines the mechanical impedance of the biological load structure coupled to the output converter. The system has at least one sensor (10a-10n) for picking up sound signals ands converting them into corresponding electrical signals, an electronic signal processing unit (12) for audio signal processing and amplification, an electrical supply unit (30) and at least one electromechanical output converter (16) for mechanical stimulation of the middle and/or inner ear. An impedance measurement arrangement (25) determines the mechanical impedance of the biological load structure coupled to the output converter in the implanted state.

Description

The present invention relates to an at least partially implantable hearing system for rehabilitation a hearing impairment with at least one sensor for recording sound signals and their conversion into corresponding electrical sensor signals, an electronic signal processing unit for audio signal processing and amplification of the sensor signals, a electrical power unit, the individual components of the system with electricity supplied, as well as with at least one electromechanical output transducer for mechanical Stimulation of the middle and / or inner ear.

The term "hearing impairment" in the present case, all types of inner ear damage, combined Inner and middle ear damage as well as occasional or permanent ear noises (Tinnitus) are understood.

Electronic measures for the rehabilitation of surgically irrecoverable inner ear damage have achieved an important status today. In case of total failure of the inner ear are cochlear implants with direct electrical stimulation of the remaining auditory nerve in the routine clinical use. For moderate to severe inner ear damage come For the first time ever, fully digital hearing aids are being used, creating a new world of electronic hearing aids Open audio signal processing and advanced possibilities of targeted audiological Fine-tune the hearing aids to the individual inner ear damage. In spite of This achieved in recent years, significant improvements in the equipment hearing aid supply remain conventional hearing aids have fundamental disadvantages which are due to the principle of acoustic amplification, that is in particular by the reconversion of the electronically amplified signal into airborne sound. These disadvantages include aspects such as the visibility of the hearing aids, lack of sound quality due to the electromagnetic transducer (speaker), sealed external ear canal as well Feedback effects with high acoustic amplification.

Because of these principal disadvantages, there has been a long-felt desire, from conventional Deviate hearing aids with acoustic stimulation of the damaged inner ear and this by partially or fully implantable hearing systems with direct mechanical stimulation to replace. Implantable hearing systems differ from conventional hearing aids: Although the sound signal with an adequate microphone is converted into an electrical signal and amplified in an electronic signal processing stage; this reinforced electrical signal is not supplied to an electro-acoustic transducer (speaker), but an implanted electromechanical transducer whose output side mechanical vibrations directly, so with direct mechanical contact, the Middle or inner ear are fed or indirectly by a frictional connection via an air gap in, for example, electromagnetic transducer systems. This principle applies irrespective of a partial or complete implantation of all necessary system elements as well as regardless of whether a pure inner ear hearing loss at complete intact middle ear or a combined deafness (middle and inner ear damaged) to be rehabilitated. Therefore, in the recent scientific literature as well as in many patents implantable electromechanical transducer and method for coupling the mechanical transducer oscillations to the intact middle ear or the inner ear directly to the rehabilitation of a pure inner ear hearing loss as well as remaining ossicles of the middle ear in artificially or pathologically changed Middle ear to supply a conductive hearing loss and their combinations been described.

As an electromechanical transducer method basically all physical Conversion principles in question such as electromagnetic, electrodynamic, magnetostrictive, dielectric and piezoelectric. Various research groups have been in the last few years Essentially focused on two of these methods: electromagnetic and piezoelectric. An overview of these converter variants can be found in H.P. Zenner and H. Leysieffer (HNO 1997 Vol. 45, pp. 749-774).

In the piezoelectric method is a mechanically direct coupling of the output side Transducer oscillations to the middle ossicles or directly to the oval window necessary; In the electromagnetic principle, the power coupling can be done on the one hand via an air gap ("contactless"), that is, only the permanent magnet is replaced by permanent fixation in brought direct mechanical contact with a Mittelohrossikel. On the other hand there is the Possibility to realize the converter completely in a housing (coil and magnet are coupled with the smallest possible air gap) and the output side vibrations over a mechanically rigid coupling element with direct contact to the Mittelohrossikel too (Leysieffer, H., et al., 1997 (HNO 1997, Vol.45, pp. 792-800).

The semi-implantable, piezoelectric hearing system of the Japanese group around Suzuki and Yanigahara relies on the lack of mid-ossicles and implantation of the transducer free tympanic cavity ahead in order to connect the piezo element to the stapes (Yanigahara et al .: "Efficacy of the partially implantable middle ear implant in middle and Inner Ear Disorders ", Adv. Audiol., Vol. 4, Karger Basel (1988), pp. 149-159, Suzuki et al .: "Implantation of partially implantable middle ear implant and the indication", Adv. Audiol. Vol. 4, Karger Basel (1988), p. 160-166). Similarly, in the procedure of an implantable Hearing aid for inner ear hearing loss according to Schaefer (US-A-4 850 962) in principle the anvil is removed to couple a piezoelectric transducer element to the stapes can. This essentially also applies to further developments based on Schaefer technology based.

The electromagnetic ball transducer ("Floating Mass Transducer FMT", among others US-A-5,624,376 (Ball et al.)), On the other hand, becomes direct with intact middle ear with titanium clips fixed on the long extension of the anvil. The electromagnetic transducer of the partially implantable Fredrickson's system (Fredrickson et al .: "Ongoing investigations into an implantable electromagnetic hearing aid for moderate to severe sensorineural hearing loss ", Otolaryngologic Clinics Of North America, Vol. 28/1 (1995), pp. 107-121) is also incorporated intact ossicular chain of the middle ear mechanically coupled directly to the anvil body. The The same applies to the piezoelectric and electromagnetic transducers according to Leysieffer (Leysieffer et al .: "An implantable piezoelectric hearing aid transducer for hearing impaired people", HNO 1997/45, p. 792-800, DE-C-13 04 358, DE-C-198 40 211, DE-A-198 40 212). Also with the electromagnetic transducer system according to Maniglia (Maniglia et al.: "Contactless semi-implantable electromagnetic middle ear device for the Treatment of sensorineural hearing loss ", Otolaryngologic Clinics Of North America, Vol. 28/1 (1995), pp 121-113) is intact ossicle chain to the latter a permanent magnet Permanently mechanically fixed, but mechanically via an air gap coupling of a coil is driven.

a) Bei dem einen befindet sich der elektromechanische Wandler mit seinem aktiven Wandlerelement selbst im Mittelohrbereich in der Paukenhöhle, und er ist dort mit einem Ossikel oder dem Innenohr direkt verbunden (unter anderem US-A-5 624 376).

b) Bei dem anderen befindet sich der elektromechanische Wandler mit seinem aktiven Wandlerelement außerhalb des Mittelohrbereiches in einer artifiziell geschaffenen Mastoidhöhle; die ausgangsseitigen mechanischen Schwingungen werden dann mittels mechanisch passiver Koppelelemente über geeignete operative Zugänge (natürlicher aditus ad antrum, Eröffnung des chorda-facialis-Winkels oder über eine artifizielle Bohrung vom Mastoid aus) zum Mittel- beziehungsweise Innenohr übertragen (unter anderem DE-A-198 40 212).

In principle, two implantation principles should be distinguished in the described converter and coupling variants:

a) In one, the electromechanical transducer with its active transducer element is located even in the middle ear region in the tympanic cavity, where it is directly connected to an ossicle or the inner ear (inter alia US-A-5,624,376).

b) In the other, the electromechanical transducer with its active transducer element is located outside the middle ear area in an artificially created mastoid cavity; the mechanical vibrations on the output side are then transferred to the middle or inner ear by means of mechanically passive coupling elements via suitable operative approaches (natural aditus ad antrum, opening of the chorda facialis angle or via an artificial bore from the mastoid) (inter alia DE-A-198 40 212).

An advantage of the variants according to a) is that the converter is referred to as "floating Mass "converter can be executed, that is, the transducer element does not require" Reactio " over a firm screwing with the skull bone, but it vibrates due to Mass inertial laws with its converter housing and transmits them directly to a Mittelohrossikel. This means, on the one hand, that it is advantageous for an implantable fixation system can be dispensed with the skullcap; On the other hand, this variant is disadvantageous, that voluminous artificial elements must be introduced into the tympanic cavity and their long-term and biostability especially for temporary pathological changes of the middle ear (for example, otits media) is not known or guaranteed today are. Another major disadvantage is that the converter from Mastoid be brought from its electrical supply line into the middle ear and there with Help with appropriate surgical tools must be fixed; this requires an extended Access through the chorda facialis angle and thus brings a latent risk of in facial nerves (nervus facialis) in immediate vicinity. Farther are such "floating-mass converter" then only very limited or not at all more useful if the inner ear stimulates directly over the oval window, for example because of pathological changes, for example, the anvil is essential is damaged or no longer exists and thus such a Transducer no longer with a vibratory and with the inner ear related Ossicle can be mechanically connected.

A certain disadvantage of the converter variants according to b) is the fact that the converter housing attached to the calvarium with implantable positioning and fixation systems Need to become. Another disadvantage of the variants according to b) is that, preferably must be introduced into the Zielossikel by means of suitable lasers, wells, to apply the coupling element can. This is on the one hand technically complicated and expensive and, on the other hand, brings with it risks for the patient. Both at the partially implantable Fredrickson's system ("Ongoing investigations into an implantable elektromagnetic hearing aid for moderate to severe sensorineural hearing loss ", Otolaryngologic Clinics Of North America, Vol. 28/1 (1995), pp. 107-121) as well as the fully implantable Hearing system according to Leysieffer and Zenner (ENT 1998, Vol. 46, pp. 853-863 and 844-852) becomes permanent in the coupling of the oscillating transducer part to the anvil body and mechanically safe vibration transmission assumed that the tip a coupling rod, which introduced into a laser-induced depression of the Mittelohrossikels is, in the long term osseointegration undergoes, that is, that the coupling rod with the Ossicle firmly fuses and so a secure transmission of dynamic compressive and tensile forces guaranteed. However, this long-term effect is currently not scientifically proven.

Furthermore, there is in this coupling type in a technical converter defect of Disadvantage that a decoupling of the ossicle to remove the transducer only with mechanical based on operational methods can be undertaken, which is a significant hazard of the middle ear and especially of the inner ear.

The main advantage of these converter embodiments according to b), however, is that the middle ear remains largely free and the coupling access to the middle ear without larger Risk potential of the facial nerve can occur.

Due to the described diverse access variants and coupling techniques implantable electromechanical hearing aid transducers have been numerous coupling elements designed and described, which allows the mechanical vibration energy of the transducer as possible optimal and long-term stability to the coupling site of the middle or inner ear to transmit. In addition, implantable hearing systems have been specified in which not only one, but several electromechanical transducers are used to stimulate the damaged hearing to optimally simulate the multichannel cochlear amplifier and thus to achieve a more extensive rehabilitation of the damaged hearing than with only one transducer. On advantageous embodiments of such coupling elements and transducer assemblies will be discussed further below.

The coupling quality of the mechanical stimulus is influenced by many parameters, and she contributes significantly to the rehabilitation of hearing loss and perceived hearing quality at. Intraoperatively, this quality of coupling is difficult or impossible to assess, because the movement amplitudes of the vibrating parts, even at the highest stimulation levels in a range around or far below 1 micron and therefore not by direct visual inspection are assessable. Even if this succeeds by other technical measuring methods, for example by intraoperative laser measurements (for example by laser Doppler vibrometry), there remains the uncertainty of a long-term stable, secure coupling, since this under by necrosis, tissue neoplasmosis, changes in air pressure and others External and internal influences can be negatively affected. In particular, remains in fully implantable systems the need for docking quality of the transducer, as a full implant does not to separately measure individual system components at their technical interfaces, if For example, the implant wearer complains of a decreased transmission quality, which is due to Reprogramming of individual audiological fitting parameters can not be improved and Therefore, an operative intervention to improve the situation can not be ruled out. Also if such a case does not exist, there is in principle the interest to have a meaningful Monitor function of the long-term development of the quality of the converter coupling to feature.

In WO-A-98/36711 a method is proposed for this purpose, which with objective hearing test methods such as ERA (electric response audiometry), ABR (auditory brainstem response) or electrocochleography in partially and fully implantable systems with mechanical or electrical stimulation of the damaged or failed Hearing works. By electrical discharge via external head electrodes or implanted Electrodes are objectively determined for stimulus responses by application suitable stimulating stimuli are evoked. The advantage of this method is that Intraoperative with complete anesthesia objective data of the transmission quality determined can be. However, the main disadvantage is, inter alia, that these objective auditing methods can only be of a qualitative nature, essentially data at the hearing threshold and not or only partially suprathreshold deliver and in particular have insufficient quantitative accuracy in frequency-specific measurements. The subjective evaluation of the transmission quality as well as subjective audiological measurements in the suprathreshold area such as loudness scaling are not possible.

It has also been proposed (DE-A-199 14 992), the disadvantages mentioned by to get around that by psychoacoustic measurements, that is, by subjective patient responses, the coupling quality of the electromechanical transducer to the middle or Inner ear is determined without any further biological-technical interfaces in the evaluation the meaningfulness of the determination of converter coupling quality affect. This is realized by the fact that in the partial or in particular fully implantable hearing system on the implant side an audiometer is integrated. This audiometer consists of one or more externally adjustable or programmable electronic signal generators that provide an electrical auditory test signal in the Feed in the signal processing path of the implant. The electromechanical output transducer The implanted hearing system is thus technically reproducible and quantified electrically controlled directly; In this way, distortions of the stimulation level become avoided, as for example by Köpfhörer- or in particular acoustic Freifelddarbietungen the audiometric test sound may occur because this is also the Sensor or microphone function with all associated variabilities in the psychoacoustic Measurement is included.

One of the advantages of this procedure is that frequency-specific audiobeam measurements are used with pure sine tones or narrowband signals (for example Terzrauschen) can be reproduced very well even at longer, temporal examination intervals are. Furthermore, the method also allows the acquisition of reproducible psychoacoustic Data in the suprathreshold area such as loudness scores. About that In addition, by offering pure signals, such as sinusoidal signals, non-linearities can also be used Subjectively queried, for example, by decreasing coupling quality and can be heard as "clinking". Such investigations are by the above-mentioned objective measurement methods on the basis of evoked potentials only limited or not possible.

All mentioned methods for testing the coupling quality of the However, electromechanical transducer (s) have the or the disadvantages that either a subjective evaluation of the patient flows into the result or physiological Interfaces are included in the measurement; both aspects make the measurement result uncertain and therefore, in particular with regard to the reproducibility, not optimal Solution.

The invention is based on the object, an at least partially implantable hearing to accomplish this in a particularly reliable way, even intraoperatively an objective Measurement of the coupling quality is possible.

This object is achieved in that in an at least partially implantable Hearing system for the rehabilitation of a hearing impairment with at least one sensor for recording of sound signals and their conversion into corresponding electrical sensor signals, a electronic signal processing unit for audio signal processing and amplification of Sensor signals, an electrical power unit, the individual components of Powered system, as well as at least one electromechanical output transducer for mechanical stimulation of the middle and / or inner ear, according to the invention the hearing system for the objective determination of the coupling quality of the output transducer with an impedance measuring arrangement for determining the mechanical impedance of the implanted in the Condition provided to the output transducer coupled biological load structure is.

The principle of the present invention has the particular advantage that the coupling quality of the transducer or intraoperatively immediately after coupling to the biological Hearing structure can be assessed and if necessary improved intraoperatively, before implantation is complete without proper knowledge of the coupling success because the patient is usually operated in total anesthesia and therefore psychoacoustic Measurements are not possible.

The present invention further has the advantage that in the postoperative state the Coupling quality of the converter or the long-term objectively observed without the patient having to undergo any special procedure. This is done by way of example so that the software interface with which the audiologist or The hearing care professional adapts the implant of the patient to the individual hearing damage, contains a module with which automatically when software initialization or active Retrieve an implant-side impedance measurement is triggered and the corresponding data telemetrically transmitted to the software interface for further evaluation and evaluation.

Furthermore, according to the invention without active measuring command from the outside in certain temporal Intervals or when a particular implant operating condition such Impedance measurements are initiated and performed by the implant itself Measurement results as digital data in a dedicated memory area of the implant be stored from the outside until retrieval.

The impedance measuring arrangement may include an arrangement for measuring the input electrical impedance of the or the coupled to the biological load structure electromechanical output transducer (s) have. The amount and phase data of this electrical input impedance reflect the coupled load components, because they are connected via the electromechanical coupling of the converter (s) transformed appear on the electrical side and therefore are measurable.

It is preferably the or each electromechanical output transducer a drive unit upstream, wherein the output transducer concerned to the driver unit connected via a measuring resistor and a measuring amplifier is provided on as the input signals to the measuring resistor falling, the transformer current proportional Measuring voltage and the converter terminal voltage applied. To gauge distortions Prevent, the voltage drop across the measuring resistor is expediently high impedance and ground free tapped, and the measuring resistor is advantageously sized so that the Sum of the resistance value of the measuring resistor and the amount of the complex electrical input impedance of the coupled to the biological load structure electromechanical Output converter large compared to the internal resistance of the driver unit is. There are also - preferably digital - means for forming the quotient of converter terminal voltage and converter current provided.

Alternatively, in the context of the invention, the impedance measuring arrangement but also for direct Measurement of the mechanical impedance of the electromechanical output transducer coupled biological load structure designed and in the output transducer on the be integrated aktorischer output side, wherein preferably the impedance measuring arrangement is designed for generating measurement signals, the amount and phase of the biological Load structure acting force or the speed of the coupling element at least are approximately proportional. In this case, to process the measuring signals Advantageously, a dual-channel measuring amplifier provided with multiplexer function, and there are - preferably digital - means for forming the quotient of the measurement signal accordingly the force acting on the biological load structure and the measurement signal accordingly the fast of the coupling element available.

In the direct impedance measurement, the electromechanical output transducer and the impedance measuring arrangement may be housed in a common housing, optionally also picks up the measuring amplifier.

The described impedance measurements are in no way related to a measurement frequency or limited to a measuring level. Both indirect and direct measurement of mechanical Impedance of the biological load structure are rather advantageous - preferably digital Means for determining the mechanical impedance of the implanted state at the Output transducer coupled biological load structure as a function of frequency and / or the level of the stimulation signal delivered by the output transducer intended. Especially through measurements over the entire transmission frequency range and Stimulation level range of the respective hearing implant can in the postoperative observation phase important detail statements about linear and especially nonlinear variations the coupling quality of the or the electromechanical transducer won become. For example, a mechanical nonlinearity can be expected the coupling to a Mittelohrossikel ("rattle"), the transmitted sound quality can influence negatively, determined by electrical level variation of the impedance measurement can be.

In a further embodiment of the invention can by - preferably digital - means for Determining the spectral position of resonance frequencies in the course of the measured impedance above the pacing rate and to determine the difference between the two be provided the impedance frequencies occurring impedance measured values. This difference provides information about the mechanical vibration qualities.

The explained procedure can be basically used in all known electromechanical Conversion principles such as electromagnetic, electrodynamic, magnetostrictive, dielectric and in particular use in piezoelectric transducers, so that in the System design of the hearing implant with respect to the converter form (s) in principle no restriction exists and thus with multi-channel actuatoric system design also mixed forms various transducer principles for optimal auditory stimulation are possible.

The electromechanical output transducer can in the implanted state with the biological Load structure via a passive coupling element and / or via a coupling rod in mechanical Connection stand, and the impedance measuring arrangement can be in the coupling rod be inserted.

Preferably, the electronic signal processing unit is also for processing the signals designed the impedance measuring arrangement. Advantageously, the signal processing unit a digital signal processor for processing the sound sensor signals and / or for generating of digital signals for tinnitus masking and for processing the signals the impedance measuring arrangement. For the current measurement of the electrical transformer impedance the signal processor can interrupt the audio signal of the hearing system for a short time, to feed the appropriate measurement signals, for example from the signal processor self-generated.

When looking at a level analysis for nonlinearities of converter coupling across the whole Level useful range of the implant is omitted, the electrical transducer impedance measurement even below the patient's resting threshold to Do not disturb the patient with the measuring signals. These can be the individual, spectral Resting hearing threshold data of the patient concerned in a memory area of the system be stored, to which the measurement software of the signal processor then reference each takes.

The signal processor may be statically designed in such a way that corresponding software modules based on scientific findings unique in a program memory of the signal processor are stored and remain unchanged. But then lie later Example based on recent scientific findings improved algorithms for Speech signal preparation and processing before and should be used, must by an invasive, surgical patient intervention the entire implant or implant module, which contains the corresponding signal processing unit, against a new one with the changed Operating software to be replaced. This procedure involves renewed medical risks for the patient and is associated with great effort.

This problem can be countered by that in a further embodiment of the invention the signal processor for recording and playback of an operating program a repeatedly writable, implantable memory array is associated, and at least Parts of the operating program by an external unit via a telemetry device transmitted data can be changed or exchanged. That way after implantation of the implantable system, the operating software, including Software for controlling the above-described switchable coupling arrangement, as change or even completely exchange, as for otherwise known systems for the rehabilitation of hearing disorders in DE-C-199 15 846 is explained.

Preferably, the design is such that beyond that in fully implantable systems also in a conventional manner operating parameters, that is patient-specific Data, such as audiological fitting data, or changeable implant system parameters (For example, as a variable in a software program for controlling the switchable coupling arrangement or for regulating a battery recharge) according to Implantation transcutaneously, ie wirelessly through the closed skin, into the implant can be transferred and thus changed. The software modules are preferred dynamic, or in other words adaptive, designed to be as optimal as possible Rehabilitation of the respective hearing impairment to come. In particular, the software modules be designed adaptive, and a parameter adjustment can by "training" through the implant carrier and other aids are made.

Furthermore, the signal processing electronics may include a software module having a optimum stimulation on the basis of a learning neural network reached. The training of this neural network can be done by the implant wearer and / or with the help of other external aids.

The memory device for storing operating parameters and the memory device to record and replay the operating program can be considered independent Memory to be implemented; however, it can also be a single memory, in Both operating parameters and operating programs can be stored.

The present solution allows an adaptation of the system to conditions that only after Implantation of the implantable system can be detected. For example, at one 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 (output stimulator) biological interfaces always dependent on the anatomical, biological and neurophysiological conditions, for example of the interindividual healing process. These interface parameters can be individual and also time-variant, in particular. For example, the transmission behavior of an implanted microphone due to tissue layers and the transmission behavior of a coupled to the inner ear electromechanical transducer due to different coupling quality interindividuell and vary individually. Such differences in the interface parameters that occur at the devices known from the prior art, not even by the exchange can reduce or eliminate the implant can, in the present case by changing or improved signal processing of the implant optimized become.

• 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.

In an at least partially implantable hearing system, it may be useful or necessary to implement improved signal processing algorithms after implantation. Here are in particular to call:

• Speech analysis method (for example, optimization of a Fast Fourier Transform (FFT)),
• static or adaptive noise detection methods,
• static or adaptive noise reduction methods,
• Method for optimizing the system-internal signal-to-noise ratio,
• optimized signal processing strategies for progressive hearing impairment,
• Output level limiting method for protecting the patient in case of implant malfunction or external malfunction programming,
• Method for preprocessing a plurality of sensor (microphone) signals, in particular for binaural positioning of the sensors,
• Method for the binaural processing of two or more sensor signals in the case of binaural sensor positioning, for example optimization of spatial hearing or spatial orientation,
• Phase or group delay optimization in binaural signal processing,
• Method for optimized control of the output stimulators, in particular for binaural positioning of the stimulators.

• Verfahren zur Rückkopplungsunterdrückung beziehungsweise -minderung,
• Verfahren zur Optimierung des Betriebsverhaltens des beziehungsweise der Ausgangswandler (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 implantation, inter alia:

• Method for feedback suppression or reduction,
• Method for optimizing the operating behavior of the output transducer (for example frequency and phase response optimization, improvement of the pulse transmission behavior),
• Speech signal compression method for inner ear hearing loss,
• Signal processing methods for recruitment compensation for inner ear hearing loss.

Furthermore, in implant systems with a secondary power supply unit, the means a rechargeable accumulator system, but also in systems with primary battery supply assume that these electrical energy storage with progressive Technology ever greater lifetimes and thus increasing residence times in the patient enable. It can be assumed that the basic and application research makes rapid progress for signal processing algorithms. The need or the patient's request for an operating software customization or change is therefore expected to expire before the end of life of the implant's internal energy source enter. The system described herein allows such adaptation of the Operating programs of the implant also in the already implanted state.

Preferably, a buffer arrangement is further provided, in which of the external unit via the telemetry device before forwarding data the signal processor can be cached. In this way, the Complete the transfer process from the external unit to the implanted system, before the data transmitted via the telemetry device is forwarded to the signal processor become.

Furthermore, a verification logic may be provided which is in the buffer arrangement stored data before forwarding to the signal processor of a check subjects. It may be a microprocessor module, in particular a microcontroller, for implant-internal control of the signal processor to be provided via a data bus, wherein expedient the verification logic and the buffer arrangement in the microprocessor chip are implemented and being over 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 Saving a work program associated with the microprocessor chip, and at least Parts of the work program for the microprocessor chip may be implemented by the changed or exchanged data transmitted to the external unit via the telemetry device become.

In a further embodiment of the invention, at least two memory areas for recording and reproducing at least the operating program of the signal processor be. This contributes to the failure safety of the system by eliminating the multiple presence the memory area containing the operating program (s), for example after transmission from external or when switching on the implant a check can be made for the correctness of the software.

Analogously, the buffer arrangement can also have at least two memory areas for recording and reproducing from the external unit via the telemetry device transmitted data, so that after a data transmission from the external unit still in the area of the cache a check of the accuracy of the transmitted Data can be made. The memory areas can be used for example complementary storage of the data transmitted by the external unit. At least one of the memory areas of the buffer arrangement can also be used for Recording only part of the data transmitted by the external unit, in this case, checking the accuracy of the transmitted data in sections he follows.

To ensure that transmission errors are restarted can also be the signal processor, a preprogrammed, not be overwritten memory area assigned in which the for a "minimum operation" the system's required instructions and parameters are stored, for example Instructions that after a "system crash" at least a faultless operation the telemetry device for receiving an operating program and instructions for To store it in the control logic.

As already mentioned, the telemetry device is advantageously out of 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, so that on the one hand such parameters of a doctor, a hearing care professional or the Carrier of the system itself can be adjusted (for example, volume), on the other hand but the system can also transmit parameters to the external unit, for example to check the status of the system.

A completely implantable hearing system of the type described here can implant side in addition to the actuatoric stimulation arrangement and the signal processing unit at least have an implantable sound sensor and a rechargeable electric storage element, in which case, a wireless transcutaneous charging device for charging the memory element can be provided. It is understood, however, that for energy supply also a primary cell or another power supply unit can be present, which does not require transcutaneous recharge. This is especially true when considering that in the near future, especially by advancing the processor technology with essential Reduction of the energy demand for electronic signal processing to count so that new forms of power supply are practically applicable to implantable hearing instruments become, for example, a power supply using the Seebeck effect, as they are in DE-C 198 27 898 is described. Preferably, a wireless remote control to Control of the implant functions by the implant carrier available.

In teilimplantierbarer training of the hearing system are at least one sound sensor, the electronic signal processing unit, the power supply unit and a modulator / transmitter unit in an externally on the body, preferably on the head above the implant, to be carried external module included. The implant has the output side electromechanical Transducer and the switchable clutch assembly, but is energetically passive and receives its operating power and control data for the output-side converter and the switchable coupling assembly via the modulator / transmitter unit in the external Module.

The system described can be used in fully implantable design as well as in teilimplantierbarem Structure be designed monaural or binaural. A binaural system for rehabilitation A hearing disorder of both ears has two system units, each one of the associated with both ears. In this case, the two system units can each other substantially be equal. But it can also be the one system unit as the master unit and the be designed as a unit controlled by the master unit slave unit. The Signal processing modules of the two system units can in any way, in particular via a wired implantable lead connection or via a wireless Connection, preferably a bidirectional high frequency link, a structure-borne sound Ultrasonic path or the electrical conductivity of the tissue of the implant carrier exploiting data transmission link, communicate with each other so that in both system units an optimized binaural signal processing and converter array control is reached.

FIG. 1

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

FIG. 2

beispielhaft eine mögliche Ausführungsform des Impedanzmesssystems für einen Wandlerkanal gemäß FIG. 1,

FIG. 3

ein elektromechanisches Ersatzschaltbild für die Näherung eines piezo-elektrischen Ausgangswandlers mit angekoppelten biologischen Lastkomponenten,

FIG. 4

ein Ersatzschaltbild der elektrischen Wandlerimpedanz Z _L entsprechend FIG. 3,

FIG. 5

den Verlauf des Betrages der elektrischen Wandlerimpedanz /Z _L/ über der Frequenz f gemäß FIG. 4 in doppeltlogarithmischer Darstellung,

FIG. 6

ein Ausführungsbeispiel eines vollimplantierbaren Hörsystems mit direkter mechanischer Impedanzmessung,

FIG. 7

ein weiteres Ausführungsbeispiel eines vollimplantierbaren Hörsystems mit direkter mechanischer Impedanzmessung

FIG. 8

ein Ausführungsbeispiel eines piezoelektrischen Wandlersystems mit einem Messsystem zur Bestimmung der mechanischen Impedanz gemäß FIG. 6,

FIG. 9

ein Ausführungsbeispiel eines piezoelektrischen Wandlersystems mit einem Messsystem zur Bestimmung der mechanischen Impedanz gemäß FIG. 7,

FIG. 10

ein vollimplantierbares Hörsystem gemäß vorliegender Erfindung sowie

FIG. 11

ein teilimplantierbares Hörsystem gemäß vorliegender Erfindung.

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

FIG. 1

a block diagram of a fully implantable hearing system for the rehabilitation of a middle and / or inner ear disorder and / or tinnitus with means for electrical transducer impedance measurement,

FIG. 2

By way of example, a possible embodiment of the impedance measuring system for a converter channel according to FIG. 1,

FIG. 3

an electromechanical equivalent circuit diagram for the approximation of a piezoelectric output transducer with coupled biological load components,

FIG. 4

an equivalent circuit diagram of the electrical transformer impedance Z _L according to FIG. 3,

FIG. 5

the course of the amount of electrical transformer impedance / Z _L / on the frequency f of FIG. 4 in logarithmic representation,

FIG. 6

an embodiment of a fully implantable hearing system with direct mechanical impedance measurement,

FIG. 7

a further embodiment of a fully implantable hearing system with direct mechanical impedance measurement

FIG. 8th

An embodiment of a piezoelectric transducer system with a measuring system for determining the mechanical impedance of FIG. 6

FIG. 9

An embodiment of a piezoelectric transducer system with a measuring system for determining the mechanical impedance of FIG. seven,

FIG. 10

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

FIG. 11

a partially implantable hearing system according to the present invention.

In the fully implantable hearing system according to FIG. 1, the external sound signal is picked up via one or more sound sensors (microphones) 10a to 10n and converted into analog electrical signals. In the case of an implant realization for the exclusive rehabilitation of a tinnitus by masking or Noiserfunktion without additional hearing aid function accounts for these sensor functions. The electrical sensor signals are passed to a unit 11 which is part of an implantable electronic module 12 and in which the sensor signal or signals are selected, preprocessed and converted into digital signals (A / D conversion). The preprocessing may, for example, consist in an analogue linear or non-linear preamplification and filtering (for example antialiasing filtering). The digitized sensor signal or signals are supplied to a digital signal processor (DSP) 13, which performs the intended function of the hearing implant, such as audio signal processing in a system for inner ear hearing impairments and / or signal generation in the case of a tinnitus masker or noise. The signal processor 13 contains a non-rewritable read-only memory area S ₀ , in which the instructions and parameters required for a "minimum operation" of the system are stored, and a memory area S ₁ , in which the operating software of the intended function or functions of the implant system are stored. Preferably, this memory area will be duplicated (S ₁ and S ₂ ). The rewritable program memory for holding the operating software may be based on EEPROM or RAM cells, in which case care should be taken to ensure that this RAM area is always "buffered" by the on-board power system.

The digital output signals of the signal processor 13 are in a digital-to-analog converter (D / A) 14 converted to analog signals. This D / A converter may vary depending on the implant function be designed several times or completely eliminated if Example in the case of a hearing system with electromagnetic output transducer directly on for example, pulse width modulated, serial digital output signal of the signal processor 13 is transmitted directly to the output transducer. The analog output signal of the digital-to-analogue converter 14 is then led to a driver unit 15, depending on the implant function an output-side electromechanical transducer 16 for stimulating the Mittelbeziehungsweise Inner ear controls.

In the in FIG. 1, the signal processing components 11 and 13 to 15 are controlled by a microcontroller 17 (.mu.C) with one or two associated memories S ₄ and S ₅ via a bidirectional data bus 18. In particular, the operating software portions of the implant management system may be stored in the memory area S ₄ and S ₅ , for example, administrative monitoring and telemetry functions. In the memories S ₁ and / or S ₂ also externally variable, patient-specific, such as audiological fitting parameters can be stored. Furthermore, the microcontroller 17 has a repeatedly writable memory S ₃ , in which a work program for the microcontroller 17 is stored.

The microcontroller 17 communicates via a data bus 19 with a telemetry system (TS) 20. This telemetry system 20 in turn communicates through the indicated at 21 closed skin, for example via an unillustrated inductive coil coupling wirelessly bidirectional with an external programming system (PS) 22. The programming system 22 may advantageously be a PC-based system with appropriate programming, editing, presentation and management software. The operating software of the implant system to be changed or exchanged completely is transmitted via this telemetry interface and initially stored temporarily in the memory area S ₄ and / or S _{5 of} the microcontroller 17. For example, the memory area S _{5 may be used} for complementarily storing the data transmitted from the external system, and a simple verification of the software transmission by a telemetry read operation may be performed to determine the coincidence of the contents of the memory areas S ₄ and S ₅ 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 comprise both the operating software of the microcontroller 17 (for example housekeeping functions, such as energy management or telemetry functions) and the operating software of the digital signal processor 13. Thus, for example, a simple verification of the software transmission can be performed by a read operation via the telemetry interface, before the operating software or the corresponding signal processing components of this software are transferred to the program memory area S _{1 of} the digital signal processor 13 via the data bus 18. Furthermore, the work program for the microcontroller 17, which is stored, for example, in the repeatedly writable memory S ₃ , can be changed or replaced completely or partially via the telemetry interface 20 with the aid of the external unit 22.

On the D / A converter 14 and the respective present transducer principle of the output transducer 16 adapted driver amplifier 15 is followed by a measuring system explained in more detail below (IMS) 25 for the analog determination of the electrical transformer impedance. The of the measuring system 25 supplied analog measurement data via a measuring amplifier 26 and an associated A / D converter 27 amplified and converted into digital measurement data. The digital measurement data will be to the digital signal processor 13 of the hearing system for further processing and / or storage transmitted. This driver and impedance detection system with associated electromechanical Output transducer 16 is shown in FIG. 1 outlined in dashed lines as a unit 28 shown. Via the microcontroller 17 and the telemetry unit 20, the impedance measurement data to the Outside world to the programming and display system 22 (for example, a PC with appropriate Hardware interface).

If there are multiple electromechanical output transducers in the implantable hearing system, the unit 28 is accordingly provided several times, as shown in FIG. 1 shown in dashed lines is. The respective impedance measurement data are then transmitted to the digital signal processor 13 via a corresponding digital data bus structure provided (not shown in FIG. 1).

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

FIG. 2 shows a possible, simple embodiment of the impedance measuring system 25 for a converter channel according to FIG. 1. The coming from the digital signal processor 13 digital driver data for the electromechanical transducer 16 are converted by the D / A converter 14 into an analog signal and fed to the converter driver 15. In the present example, the output of the driver 15 is shown as a voltage source U _o with the internal resistance R _i . The analogue output signal of this driver 15 is fed to the electromechanical transducer 16 having a complex electrical impedance Z _L via a measuring resistor R _m .

If the sum of R _m and the amount of Z _{L is} large compared to R _i , the voltage is impressed on the electromechanical transducer 16. If the voltage drop across R _{m is} detected with the measuring amplifier (MV) 26 shown correspondingly high-impedance and ground-free, there is a The measurement current U _I proportional to the converter current I _W available. At the same time, the converter amplifier voltage U _w is available to the measuring amplifier 26. By corresponding A / D conversion of these measurement voltages in the A / D converter 27, both data sets are digitally available to the digital signal processor 13. By appropriate digital quotient formation thus the determination of the complex electrical converter impedance Z _L = U _W / I _W by amount and phase is possible. The respective basic functions of the driver and impedance measuring unit 28 are set by the microcontroller 17 via a digital control bus 31.

FIG. 3 shows in an equivalent electromechanical circuit diagram the approximation of a piezoelectric transducer with coupled biological load components. The piezoelectric transducer is determined on the electrical impedance side Z _EI essentially by a rest capacity C _o and a loss conductance G. An electromechanical unit converter 33 with an electromechanical conversion factor α is followed by the mechanical components of the converter itself, which represent the mechanical impedance Z _W. If a piezoelectric transducer is operated highly tuned, that is, the first mechanical resonance frequency is at the upper end of the spectral transmission range, as explained in more detail in US-A 5 277 694, then the mechanical impedance of the transducer Z _{W is} well approximated by the mechanical components dynamic transducer mass m _W , transducer stiffness s _W and the Wandlerreibwiderstand (real share) W _W determined. The biological, mechanical load impedance Z _B is in the present example by the three mechanical impedance components mass m _B (for example, mass of a Mittelohrossikels), stiffness s _B (for example, stiffness of the clamping ring band of Stirrbügelfußplatte in the oval window) and frictional resistance W _B (for Example, connective tissue at the coupling site). Assuming that on the mechanical load side, both the converter and the biological load components experience the same speed (mechanical parallel connection), after the mechanical components have been transformed by the unit converter 33 to the electrical side, an equivalent electrical circuit diagram is obtained. 4 is shown.

FIG. 4 shows the equivalent circuit of the electrical transformer impedance Z _L according to FIG. 3, the coil L _M reflecting the sum of the masses mw and m _B , the capacitance C _M the mechanical parallel connection of the stiffnesses sw and s _B and the resistance R _M the mechanical parallel connection of the components W _W and W _B.

FIG. 5 shows the profile of the amount of the electrical transformer impedance / Z _L / over the frequency f according to FIG. 4 in logarithmic representation. One recognizes a basically capacitive profile of / Z _L /, which is determined by C _o . The occurring series resonance at f ₁ and the parallel resonance at f ₂ are determined by the components L _M and C _M with C _o . The size Δ / Z _L / provides information about the mechanical quality of the vibration. Thus, very accurate information about the quality of the coupling and its temporal course can be obtained postoperatively from the spectral position of f1 and f2 and the quantity Δ / Z _L /, in particular if the impedance measurements represent the entire spectral and level range of the hearing implant.

FIG. 6 shows a fully implantable hearing system largely in accordance with the system of FIG. 1, but with the variant of the direct mechanical impedance measurement. After the D / A converter 14 and the driver amplifier 15 adapted to the intended transducer principle, a unit 35 accommodated in a housing 34 follows with an output-side electromechanical transducer 36 which has an electromechanically active element 37, for example a piezoelectric and / or electromagnetic system , On the actuator output side, a mechanical impedance measuring system 38 is integrated in the transducer 36, which measures the force F applied to the coupled biological load structure and the velocity v of a coupling element 39 in terms of magnitude and phase in the implanted state. The biological load structure is not shown.

Impedance measurement system 38 provides electrical analog sensing signals S _F and S _v , which are respectively proportional to force F and velocity v . These analog measurement signals are converted into digital measurement data via a corresponding two-channel measurement amplifier 40 with multiplexer function and associated A / D converter 27 and transmitted to the digital signal processor 13 of the hearing system for further processing and / or storage. The formation of the complex mechanical impedance Z (f, P) = F / v as a function of the frequency f and the measurement level P can be done either by an analog computer in the sense amplifier 40 or after appropriate software-based A / D conversion in the digital signal processor 13. This driver and impedance detection system with associated electromechanical transducer 36 is shown in dashed lines as a unit 41 shown. Via the microcontroller 17 and the telemetry unit 20, the impedance measurement data to the outside world to the programming and display system 22 (for example, a PC with corresponding hardware interface) can be transmitted.

Are multiple electromechanical transducers 36 provided in the implantable hearing system, the dashed fringed unit 41 is to be completed accordingly, as shown in FIG. 6 also shown in dashed lines. The respective impedance measurement data become the digital one Signal processor 13 then via a corresponding digital data bus structure available provided (not shown in detail in FIG. 6).

The remaining components of the hearing system of FIG. 6 correspond to those of FIG. 1 and therefore require no further explanation.

FIG. 7 shows a fully implantable hearing system with the variant of direct mechanical Impedance measurement according to FIG. 6, where here the corresponding two-channel amplifier 40 with multiplexer function and the associated A / D converter 27 for the detection of the power and rapid signal are integrated into the housing 34 of the unit 35. The electromechanical active element of the transducer 36 and the measuring system for determining the mechanical Load impedance are shown together as element 42 here. The coupling element for biological load is again designated 39.

Structure and operation of the system according to FIG. 7 otherwise correspond to those of the system of FIG. 6th

FIG. 8 shows by way of example the structure of the unit 35 according to FIG. 6 with a piezoelectric Converter system according to US-A 5 277 694 and an additional measuring system for determination the mechanical impedance. The in FIG. 8 unit 35 has a biocompatible, cylindrical housing 34 made of electrically conductive material, for example Titan, on, which is filled with inert gas. In the housing 34 is a vibratory, electric conductive diaphragm 46 of the output-side electromechanical transducer 36 is arranged. The membrane 46 is preferably circular, and is at its outer edge with the Housing 34 firmly connected. At the in FIG. 8 lower side of the membrane 46 sits a thin Disk 47 of piezoelectric material, for example lead zirconate titanate (PZT). The the diaphragm 46 facing side of the piezoelectric disk 47 is connected to the membrane 46 in electrical conductive connection, and that suitably via an electrically conductive adhesive bond. On the side facing away from the membrane 46 side of the piezo disk 47 is a contacted thin flexible wire, which is part of a signal line 48 and in turn via a hermetic housing feedthrough 49 with an outside of the housing 34 lying Converter lead 50 is connected. At 52, in FIG. 8 a polymer grout between the Outside of the housing 34, the housing bushing 49 and the transducer lead 50 indicated. A ground connection 53 is provided from the transformer feed line 50 via the housing feedthrough 49 guided to the inside of the housing 34.

The application of an electrical voltage between the signal line 48 and the ground terminal 53 causes a bending of the hetero-composite membrane 46 and piezoelectric disk 47 and thus leads to a deflection of the membrane 46. Also in the present Arrangement advantageously applicable details of such a piezoelectric transducer are otherwise explained in US-A 5 277 694. An output side electro-mechanical Transducer 36 of this type typically has a relatively high mechanical output impedance, in particular, a mechanical output impedance which is higher than the mechanical load impedance in the implanted state to the transducer coupled biological middle and / or inner ear structure.

In the illustrated embodiment, for connecting the transducer 36 to the biological load structure, for example, any middle ear ossicle, a coupling rod 55 and a passive coupling element 56 provided on the of the transducer 36th remote end of the coupling rod 55 is attached or from this coupling rod end itself is formed. The coupling of the output side of the transducer 36 to the biological Load structure, such as a Zielossikel, takes place via the mechanical impedance measuring system 38, which with the in FIG. 8 upper side of the membrane 46, preferably in the center the membrane is in mechanical communication. The impedance measuring system 38 can with its membrane-side end directly to the membrane 46 and with its other end at the membrane-side end of the coupling rod 55 attack; but it can also be in the Coupling rod 55 inserted.

The coupling rod 55 extends at least approximately in the illustrated embodiment perpendicular to the membrane 46 by an elastically compliant polymeric seal 57 from the outside into the interior of the housing 34. The polymer seal 57 is such, that it allows axial vibrations of the coupling rod 55 in the implanted state.

The impedance measuring system 38 is housed within the housing 34. The analog measuring signals S _F and S _v are transmitted from the impedance measuring system 38 via measuring lines 59, 60, signal passages 61 in the housing and the housing bushing 49 to the converter lead 50. The impedance measuring system 38 is further connected via a ground terminal 62 to the housing 34 and via this housing to the ground terminal 53 in electrically conductive connection. The reference potential of the two measuring signals S _F and S _v for force and speed is thus the converter housing 34. If the impedance measuring system 38 is preferably constructed on the basis of piezoelectric transducers and therefore active electrical impedance transformers in the measuring system are necessary, these can be supplied via an electrical phantom power supply Electronic module 12 of the implantable hearing system from one of the two implant measuring leads 59, 60 are supplied with power for operation or fast with power.

FIG. 9 shows an example of a piezoelectric transducer system with measuring system for the determination the mechanical impedance according to FIG. 7, in which case the measuring amplifier 40 and associated A / D converter 27 in a connected via leads 63 separate electronic module 64 are housed in the converter housing 34 with. The impedance measuring system 38 and the separate electronics module 64 can be connected via an electrical phantom power from Electronic module 12 of the implantable hearing from one of two active implant lines (Signal line 48 for the Aktreibreibersignal or a signal line 65 for the digital A / D output signal) are supplied with operating energy.

FIG. 10 schematically shows the structure of a fully implantable hearing system, referred to as Actuator stimulation arrangement an output-side electromechanical transducer 16th or 36, for example, the transducer of FIG. 8 or FIG. 9, has. The output side Electromechanical transducers can generally be considered as any electromagnetic, electrodynamic, piezoelectric, magnetostrictive or dielectric (capacitive) transducer be educated. Among other things, the converter shown in Figures 8 and 9 also be modified in the manner explained in DE-C-198 40 211 that at the in Figures 8 and 9 lower side of the piezoelectric ceramic disc 47, a permanent magnet attached, which is like an electromagnetic transducer with an electromagnetic coil interacts. Such a combined piezoelectric / electromagnetic Transducer is especially in terms of a wide frequency band and on the achievement of relative large vibration amplitudes with relatively small power supplied advantage. The output-side electromechanical transducer may also be an electromagnetic Transducer arrangement as described in EP-A-0984 663. In In any case, the presently explained measuring system 25 or 38 is additionally provided.

For coupling the electromechanical transducer 16 or 36 to the middle or inner ear Coupling arrangements according to US Pat. No. 5,941,814, in which a coupling element is particularly suitable, are particularly suitable has a crimping sleeve except for a coupling part for the respective coupling point, the first loose on a provided with a rough surface rod-shaped part of a Coupling rod is pushed, which is connected in the manner explained above with the transducer is. When implanting the crimp barrel can be easily moved relative to the coupling rod and rotated to the coupling part of the coupling element with the intended Align coupling point exactly. Then the crimping sleeve is fixed by means of a crimping tool is plastically cold worked. Alternatively, the coupling element with Regarding the coupling rod also be determined by means of a zugziehbaren belt loop.

Other presently preferred coupling arrangements are in detail in DE-A-199 23 403, DE-A-199 35 029, DE-C-199 31 788, DE-A-199 48 336 and DE-A-199 48 375. Thus, according to DE-A-199 23 403 a coupling element at its Ankoppelende have a contact surface, the one to the surface shape of the coupling point customizable or customized surface shape and surface finish and surface area having it by applying the Ankoppelendes the coupling point to a dynamic train-pressure-power coupling of coupling element and Ossicular chain comes through surface adhesion, which ensures a secure mutual connection sufficient of coupling element and ossicle chain. The coupling element can be implanted with a Condition at the coupling point adjacent attenuator with entropy-elastic Be provided with properties to an optimal vibration form of the stirrup footplate or one the round window or an artificial window in the cochlea, in the vestibule or to reach the labyrinth-terminating membrane and the risk of damage the natural structures in the area of the coupling site during and after implantation To keep particularly low (DE-A-199 35 029).

The coupling element can according to DE-C-199 31 788 with an adjusting device for optionally adjusting the coupling element between an open position, in which the Coupling element in and out of engagement with the coupling point can be brought, and a closed position be provided, in which the coupling element in the implanted state with the coupling point is in force and / or positive connection.

For mechanically coupling the electromechanical transducer to a preselected coupling point Furthermore, a coupling arrangement is suitable on the ossicular chain (DE-A-199 48 336), one of the transducer into mechanical vibrations displaceable Coupling rod and one with the preselected Ankoppelstelle be brought into connection Coupling element, wherein the coupling rod and the coupling element via at least a coupling are connected together and at least one in the implanted state the Ankoppelstelle adjacent portion of the coupling element for low-loss oscillation initiation is designed in the Ankoppelstelle, wherein a first coupling half of the Clutch an outer contour with at least approximately the shape of a spherical cap has, in an outer contour at least partially complementary inner contour a second coupling half is receivable, and wherein the coupling against frictional forces reversible pivoted and / or rotatable, but occurring in the implanted state dynamic forces is essentially rigid. According to a modified embodiment Such a coupling arrangement (DE-A-199 48 375) has a first coupling half the coupling has an outer contour with at least approximately cylindrical, preferably circular cylindrical shape that in a to the outer contour at least partially complementary inner contour of a second coupling half is receivable, wherein a in implanted state at the coupling point abutting portion of the coupling element to low-loss oscillation initiation is designed in the Ankoppelstelle, wherein in the implanted Condition a transfer of dynamic forces between the two coupling halves the coupling substantially in the direction of the longitudinal axis of the first coupling half takes place, and wherein the coupling reversible on and uncoupled and reversible linear and / or rotationally adjustable with respect to a longitudinal axis of the first coupling half, but is rigid in the implanted state occurring dynamic forces.

To the in FIG. The fully implantable hearing aid shown in FIG. 10 is also included implantable microphone (sound sensor) 10, a wireless remote control 69 for control the implant functions through the implant carrier and a wireless, transcutaneous charging system with a charger 70 and a charging coil 71 for reloading the implant secondary battery 30 (Figures 1, 6 and 7) for powering the hearing system.

The microphone 10 can advantageously be constructed in the manner known from EP-A-0 831 673 and with a microphone capsule housed in a housing hermetically sealed on all sides is, as well as with an electrical feedthrough assembly for performing at least one electrical connection provided by the interior of the housing to the outside thereof be, wherein the housing has at least two legs which at an angle with respect are aligned with one another, the microphone capsule receives and with a sound entry diaphragm is provided, wherein the other leg, the electrical feedthrough assembly contains and set back from the plane of the sound inlet membrane is, and wherein the geometry of the microphone housing is selected so that at implantation of the microphone in the mastoid cavity of the leg containing the sound inlet membrane from the mastoid into an artificial hole in the posterior, bony canal wall protrudes and the sound inlet membrane touches the skin of the ear canal wall. To lay down of the implanted microphone 38 may suitably a fixation of the Be provided US-A-5 999 632 known type having a sleeve, which with a cylindrical housing part enclosing the leg containing the sound inlet membrane and with the side of the auditory canal wall facing the auditory canal, projecting, elastic flange parts is provided. This includes the fixation element preferably a holder, which said flange parts prior to implantation against a resilient restoring force of the flange in a the insertion through the bore of the ear canal wall allowing bent position.

The charging coil 71 connected to the output of the charging device 70 preferably forms in the type known from US-A-5 279 292 part of a transmission series resonant circuit, with a non-illustrated receive series resonant circuit are inductively coupled can. The receive-series resonant circuit may be part of the implantable electronic module 12 (Figures 1, 6 and 7) and according to US-A-5 279 292 a constant current source for form the battery 30. In this case, the receive series resonant circuit lies in a battery charging circuit, the depending on the respective phase of flowing in the charging circuit Charging current over one or the other branch of a full-wave rectifier bridge is closed.

The electronic module 12 is in the arrangement of FIG. 10 via a microphone line 72 at the microphone 10 and the transducer lead 50 to the electromechanical transducer 16th or 36 and the measuring system 25 or 38 connected.

FIG. 11 shows schematically the structure of a partially implantable hearing system. In this partially implantable System are a microphone 10, an electronic module 74 for an electronic Signal processing largely according to FIG. 1, 6 or 7 (but without the telemetry system 20), the power supply (battery) 30 and a modulator / transmitter unit 75 in an externally on the body, preferably on the head above the implant to be worn external Module 76 included. The implant is energetically passive as in known partial implants. Its electronic module 77 (without battery 30) receives operating power and control signals for the transducer 16 or 36 and the measuring system 25 or 38 via the modulator / transmitter unit 75 in the external part 76. The electronic module 77 and the modulator / transmitter unit 75 included the necessary telemetry unit for the transmission of the impedance measurement data to the Extracorporeal unit 76 for further evaluation

Both the fully implantable and the partially implantable hearing system can be monoaural (as shown in Figures 10 and 11) or be designed binaurally. A binaural system for the rehabilitation of a hearing disorder in both ears has two system units, the each associated with one of the two ears. The two system units be essentially the same. It can also be the one system unit as a master unit and the other system unit as a slave unit controlled by the master unit be designed. The signal processing modules of the two system units can be used on any Manner, in particular via a wired implantable cable connection or via a wireless connection, preferably a bidirectional radio frequency link, a structure-borne ultrasound path or the electrical conductivity of the tissue the implant carrier exploiting data transmission path, communicate with each other, that optimized binaural signal processing is achieved in both system units becomes.

• 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 foreseeable:

• Both electronic modules can each contain a digital signal processor according to the above description, wherein the operating software of both processors as described transcutaneously changeable. Then, the connection of both modules essentially ensures the exchange of data for optimized binaural signal processing, for example of the sensor signals.
• Only one module contains the digital signal processor described, in which case the module connection, in addition to the sensor data transmission for binaural sound analysis and accounting, also provides 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 stored only in one module and is only transactively changed externally via a single-sided telemetry unit. In this case, the energetic supply of the entire binaural system can be accommodated in only one electronic module, wherein the energetic supply of the contralateral module is wired or wireless.

The described arrangements and measures are readily available in conjunction with hearing systems where multiple output-side electromechanical transducer for excitation the fluid-filled inner ear spaces of the damaged inner ear are provided, and wherein the signal processing unit is a driving signal processing electronics which electrically energizes each of the transducers such that on the basilar membrane of the damaged inner ear a traveling wave configuration arises, which is the type of traveling wave training a healthy, not damaged inner ear approximiert (older EP patent application 00 119 195.6) or in which as an actoric stimulation arrangement a dual intracochlear array is provided, 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 stimulation electrode arrangement with at least a cochlear implant electrode for electrical stimulation of the inner ear (older EP patent application 01 109 191.5).

Claims (19)

1. At least partially implantable hearing system for rehabilitation of a hearing disorder comprising at least one sensor (10) for picking up sound signals and converting them into corresponding electrical sensor signals, an electronic signal processing unit (12; 74, 77) for audio signal processing and amplification of the sensor signals, an electrical power supply unit (30) which supplies individual components of the system with energy, as well as at least one electromechanical output transducer (16, 36) for mechanical stimulation of the middle and/or inner ear, characterized in that, the hearing system, for objectively determining the coupling quality of the output transducer (16, 36), comprises an impedance measuring means (25, 38) for determining the mechanical impedance of the biological load structure which in the implanted state is coupled to the output transducer.
2. System as defined in claim 1, characterized in that the impedance measuring means (25) comprises means for measuring the electrical input impedance of the electromechanical output transducer (16) which is coupled to the biological load structure.
3. System as defined in claim 2, characterized in that a driver unit (15) is connected upstream to the electromechanical output transducer (16), the output transducer is connected to the driver unit via a measuring resistance (R_m), and a measuring amplifier (26) is provided, which has applied thereto as input signals the measuring voltage (U _I) which is dropped at the measuring resistance (R_m) and is proportional to the transducer current (I_w), and the transducer terminal voltage (U _W).
4. System as defined in claim 3, characterized in that the voltage drop (U _I) at the measuring resistance (R_m) is taken off at high impedance and with floating ground.
5. System as defined in claim 3 or 4, characterized in that the measuring resistance (R_m) is dimensioned such that the sum of the resistance value (R_m) of the measuring resistance and of the absolute value of the complex electrical input impedance (Z _L) of the electromechanical output transducer (16) coupled to the biological load structure is large with respect to the internal resistance (R_i) of the driver unit (15).
6. System as defined in any one of claims 3 to 5, characterized by - preferably digital - means (13) for forming the quotient of the transducer terminal voltage (U _W) and the transducer current (I _w).
7. System as defined in claim 1, characterized in that the impedance measuring means (38) is designed for direct measurement of the mechanical impedance of the biological load structure coupled to the electromechanical output transducer (36) and is integrated into the output transducer at the actoric output side thereof.
8. System as defined in claim 7, characterized in that the impedance measuring means (38) is designed for generating measuring signals (S_F and S_v) which, in terms of absolute value and phase, are at least approximately proportional to the force (F) acting on the biological load structure or the velocity (v), respectively, of the coupling element (55. 56), and in that a measuring amplifier (40) with multiplex function, which preferably has two channels, is provided for processing the measuring signals (S_F and S_v).
9. System as defined in claim 8, characterized by - preferably digital - means (13) for forming the quotient of the measuring signal (S_F) corresponding to the force (F) acting on the biological load structure and the measuring signal (S_v) corresponding to the velocity (v) of the coupling element (55, 56).
10. System as defined in any one of the preceding claims, characterized by - preferably digital - means (13) for determining the mechanical impedance of the biological load structure which in the implanted state is coupled to the output transducer (16, 36) as a function of the frequency and/or the level of the stimulation signal delivered by the output transducer (16, 36), and preferably for detecting the spectral location of resonance frequencies (f1 and f2) in the course of the measured impedance as a function of the stimulation frequency (f), and preferably for detecting the difference Δ/Z _I/ between the impedance values occurring at the resonance frequencies (f1 and f2).
11. System as defined in any one of the preceding claims, characterized in that a software surface for adapting the hearing system to an individual hearing disorder comprises a module, which automatically by software initialization or via direct request initiates an implant-side impedance measurement and transmits the respective data via telemetric transmission to the software surface for further analysis and evaluation.
12. System as defined in any one of the preceding claims, characterized in that it is designed such that, without active measuring command from the outside, impedance measurements are automatically initiated and carried out at predetermined time intervals or at the occurrence of a predetermined operational condition of the implant, wherein the measurement results are stored as digital data in a respective storage area of the implant until retrieval from the outside.
13. System as defined in any one of claims 7 to 12, characterized in that the impedance measuring means (38) is inserted in the coupling rod (55) via which the electromechanical output transducer (16, 36), in the implanted state, is mechanically connected to the biological load structure.
14. System as defined in any one of the preceding claims, characterized in that the signal processing unit (12; 74, 77) comprises a digital signal processor (13) for processing the audio sensor signals and/or for generating digital signals for tinnitus masking as well as for processing the signals of the impedance measuring means (38).
15. System as defined in claim 14, characterized in that a repeatedly rewritable implantable storage arrangement (S₁, S₂,) is assigned to the signal processor (13) for storage and retrieval of an operating program, and in that at least parts of the operating program can be altered or replaced by data transmitted from an external unit (22) via a telemetry means (20).
16. System as defined in claim 15, characterized in that it further comprises a buffer storage arrangement (S₄, S₅) in which data transmitted from the external unit (22) via the telemetry means (20) are buffered before being relayed to the signal processor (13), and preferably there is further provided a checking logic (17) for checking data stored in the buffer storage arrangement (S₄, S₅) before said data are relayed to the signal processor (13).
17. System as defined in any one of claims 14 to 16, characterized by a microprocessor module (17), particularly a microcontroller, for implant-internal control of the signal processor (13) via a data bus (18).
18. System as defined in claim 17, characterized in also program parts or entire software modules can be transferred via the data bus (18) and the telemetry means (20) between the outer world, the microprocessor module (17) and the signal processor (13).
19. System as defined in claim 17 or 18, characterized in that an implantable storage arrangement (S₃) for storage of an operating program for the microprocessor module is assigned to the microprocessor module (17), and at least parts of the operating program for the microprocessor module can be altered or replaced by data transmitted from the external unit (22) via the telemetry means (20).

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