WO2017025074A1

WO2017025074A1 - Measuring device for mechanical-electric measurement and monitoring of physiological activities in an electrically evoked stapedius muscle tissue (ekehrt sensor)

Info

Publication number: WO2017025074A1
Application number: PCT/DE2016/000290
Authority: WO
Inventors: Karsten Ehrt; Rüdiger Dahl; Attila OVARI; Robert Arndt MLYNSKI
Original assignee: Universität Rostock
Priority date: 2015-08-08
Filing date: 2016-07-26
Publication date: 2017-02-16
Also published as: DE112016003629A5; DE102015010272A1

Abstract

The invention relates to a measuring device for measuring and monitoring physiological activities in an electrically evoked stapedius muscle tissue (eKEHRT sensor), in particular for contactless measuring of physiological activities of electrically evoked tissue which is located in the human middle ear, which consists of a biocompatible sensor element (1), wherein the biocompatible sensor element (1) is arranged at or on or around a movable structure in the cavum of the middle ear using a corresponding fastening element (4), and connected via a discharge electrode (5) to the cochlea implant (not shown), and the round magnet (6) for producing a magnetic field is inserted in the cochlea implant for fastening the external speech processor. An additional mini coil (7), which increases the sensitivity of the sensor element (1) and makes adjustment of the sensor element (1) easier, is integrated on or in the discharge electrode (5) or fastened in a bone window the middle ear cavity.

Description

Measuring device for the mechanoelectric measurement and monitoring of physiological activities in an electrically evoked stapedius muscle tissue (eKEHRT sensor)

The invention relates to a measuring device for measurement and monitoring

physiological activities in an electrically evoked Stapediusmuskelgewebe (eKEHRT sensor), in particular for non-contact measurement of the physiological activity of electrically evoked tissue, which is located in the middle ear of the human.

The human ear can be subdivided into the outer ear, middle ear and inner ear. The middle ear includes eardrum, the eustachian tube, the tympanic cavity with the

Ossicular chain, ligaments and middle ear muscles. The ossicles Ossicular chain consists of hammer, anvil and stirrup. The eardrum is set in vibration by incoming sound waves through the outer ear.

These vibrations can now be transmitted via hammer, anvil and stirrup to the oval window of the inner ear, causing volume changes in the liquid of the cochlea. By the movement of the liquid, hair cells projecting into the cochlea are bent, triggering nerve impulses. In the middle ear, a mechanical impedance transformation takes place, which allows optimal transmission of the sound signal from the outer ear to the inner ear. In addition, the eardrum muscle (M. tensor tympani) and the so-called stapedius muscle (M. stapedius) are located in the middle ear. The tympanic muscle is inserted on the hammer, with the stapedius muscle connected to the stapes bones via a tendon. In the case of too high a sound pressure, which could damage the inner ear, both muscles contract reflexively, so that the mechanical coupling of the eardrum to the inner ear (and thus the power transmission) is reduced. As a result, a protection of the inner ear against excessive sound pressure is possible. The tension of the stapedius muscle, which is triggered by high sound pressure, is also called a stapedius reflex. From the diagnosis of the stapedius reflex it is possible to obtain medically relevant information about the functionality of the ear. Furthermore, the measurement of the Stapediusreflexes for setting or calibration is so

mentioned cochlear implants useful because of the measured Stapediusreflex on the sonic energy perceived by a patient can be closed. It is known to use for measuring the Stapediusreflexes electrodes which are brought into contact with the stapedius muscle and the action currents or action potentials generated in a contraction of the stapedius muscle to a

Forward measuring device. This is a reliable, minimally invasive

Contacting the stapedius muscle difficult, since the stapedius muscle is disposed within a cavity present in a bone and only the connected to the stirrup tendon of the stapedius muscle and the upper part of the interior of the middle ear are accessible.

An existing measuring system for ESRT measurement (Electrically Evoked Stapedius Reflex Threshold) consisting of a first electrode and a

Fixing element is described in WO 2008 148 822 A1, wherein the first electrode is connected to a first elongated electrical line and wherein the first electrode of an elongated base body (with a first end) and a second end, wherein the first electrical line with the

Base body is connected in the region of the second end and wherein means are provided for reversibly fixing the fixing element to the first electrode. This electrode arrangement is used to measure the action current and / or the action potential of an electrically active tissue, preferably the

Stapediusmuskelgewebes. The fixation of the first electrode in the stapedius muscle tissue is carried out by a separately introduced fixation element, wherein the fixing element penetrates the base body of the first electrode, preferably the lateral surface and thus, for example, on the tendon of the

Stapedius muscle fixed.

The invention according to DE 60 032 490 T2 describes a system for adapting the function of a cochlear implant, wherein the cochlear implant for

Application of excitations by means of a plurality of electrodes over a range of values, wherein the cochlear implant contains a means for detecting generated electrical voltage signals of the hearing system in response to an applied stimulus / excitation. The system includes

Processing means, coupled to the cochlear implant and adapted to analyze the electrical voltage signals, provide an optimum value for an excitation signal in response to at least one selected parameter determined, which is derived from the electrical voltage signals. There is a bipolar measurement of the action potential of the tissue.

In DE 10 2007 026 057 A1 an electrode and measuring device for

Measuring the electrical activity in an electrically active tissue, wherein the electrode has an elongated electrode body having a first end and a second end. The electrode is shaped such that it can be passed through a tissue only in a forward direction along the longitudinal axis of the electrode body. Preferably, the

Electrode base body Means for permanent or temporary mechanical blocking of the movement of the electrode through a tissue in one

Reverse direction along the longitudinal axis of the electrode body.

Thereby, a backward sliding out (backward movement) of the electrode can be avoided. Thus, a tissue-preserving fixation of the electrode is possible. After the measurement of muscle activity, the inventive

Electrode can be easily removed by further in

Forward direction is moved through the tissue and thus removed from the tissue. In contrast, conventional electrodes are removed from the tissue at the back. Therefore, there is no sense in the mechanical blocking of the movement of the electrode in the backward direction along the longitudinal axis.

Preferably, the electrode body is flexible and has at least one passive or active fixing element. Preferably, at least three passive or active fixing elements are arranged circumferentially on the electrode base body and the fixing elements are arranged at the same angle in a plane perpendicular to the longitudinal axis (evenly distributed) from each other. In a particularly preferred embodiment of the invention, the at least one fixing element is formed by a hook or by a spring.

The invention according to DE 69 728 173 T2 relates to an implantable cochlear stimulator (ICS) with an implantable self-adaptive circuit for adapting such ICS to a specific patient, wherein "adapting" to the process of determining and setting the amplitude or intensity of the stimuli generated by the ICS to a level or adaptation that both effectively, ie, allows the ICS to perform its intended function optimally, and is comfortable and thus not excessively loud or painful to the patient. A method for self-adapting an ICS to a specific one To determine patients using objective feedback rather than subjective feedback to determine the pacing parameters for the patient.

US Pat. No. 6,208,882 (B1) describes a stapedial reflex electrode and plug for detecting a patient's stapled reflexes, and an implantable connector used to electrically connect the stapledius reflex electrode to an implantable cochlear stimulator (ICS) or other implantable device. In this case, an electrode within the

Stapedius muscle or at a nearby location where the stapedius muscle is visible and where it leaves a bony canal in the middle ear. The

Electrode is designed as a biocompatible metal wire with a flat blade and provided with a sharp tip and serrations along one edge. An insulated wire is electrically and mechanically attached to the blade. Such attachment may be made by welding and wrapping the insulated lead at one end of the wire around the body of the electrode and protecting such weld and wrap fasteners with covers with a coating of epoxy resin. During implantation of the electrode, the electrode blade is inserted through a small slit in the muscle tissue. Alternatively, the electrode next to the muscle tissue through an opening in the

Bone wall are inserted, which passes through the bone canal, wherein the electrode protrudes with a tip from the bone canal. The projecting tip is then bent over to rest and fix against the bone wall. Other embodiments of a stirrup electrode are also shown, with the distal end of a multi-core insulated wire in the

Stapedius muscle tissue is embedded with a needle. A fitting is used to electrically connect a lead to the form of the implanted electrode in conjunction with a stapes implant device. The tube connector is a platinum tube that is welded at one end to a lead from the implant device. A proximal end of the lead of the electrode is crimped at the other end of the tube. A silicone tube or sleeve is then placed over the tube and sealed at both ends.

The current practice is to observe the stapedial muscle activity during or after electrical stimulation under the surgical microscope and manually to register. After the end of the operation, no observation or monitoring is possible.

The invention according to US 201 10255 731 A1 describes a transducer and external magnetic fields, in particular a transducer which can be used to monitor the stirrup of a human ear Implants are often electromagnetic transducers which serve as an actuator, a sensor and / or a switch The transducer includes a housing and at least one coil coupled to the housing, a magnet being within the housing

arranged and biased by the biasing elements. The biasing elements are used at a resonant frequency, thus reducing the friction between the magnet and the inner surface of the housing, which may cause interference. Electrical signals through the at least one coil cause the magnet to oscillate with respect to the housing along an axis. The vibration of the magnet causes inertial vibration of the housing, thus generating vibrations in the inner ear. Implants can too

Electromagnetic sensors include using electromagnetic sensors that can be used without restriction in converting the mechanical vibrations of an ossicle in the middle ear into an electrical signal. Another application of an electromagnetic sensor can detect the stapedius reflex. Medically relevant

Information about the functionality of the ear can be obtained from the diagnosis of the stapedius reflex detection. Furthermore, the measurement of

Stapediusreflexe used for setting and / or calibration of so-called cochlear implants, since the sound energy can be perceived by a patient from the measured Stapediusreflexen.

A previously filed patent application DE 10 2014 009 387.5 describes a sensor arrangement for registering electrical activities in the target tissue, consisting of a Hall sensor and a permanent magnet. The

Measuring device is used for non-contact mechanoelectric measurement and monitoring of physiological activities in an electrically evoked

Stapedius muscle tissue (KEHRT sensor) for setting and calibrating cochlear implants, the measuring device being made of a biocompatible

Sensor element which is arranged on or on or around a movable structure in the cavity of the middle ear with a corresponding fastener and is connected via a deflection electrode with the cochlear implant, not shown. The sensor element is designed as a biocompatible measuring electrode or as a biocompatible Hall sensor, wherein the round magnet used in the cochlear implant for fixing the external speech processor and / or integrated on or at the discharge electrode or arranged in a bone window in the middle ear cavity Miniature magnet for generating a

Magnetic field is used.

The mechanoelectric transducers described in the prior art are based on the fixation of a coil. It is not apparent from the illustrations how the necessary relative movement of the magnetic core with respect to the coil winding is achieved. The transmission of the movement of the ossicular chain on a movable magnetic core within a coil only leads to one

Induction voltage when the coil is fixed relative to the movable magnetic core. The disadvantages of the above-mentioned prior art result from the described operating principles. Technically, the necessary

Size ratios when using manual surgical techniques high demands. The arrangement and shape of the measuring electrodes described in the electrically active tissue (stapedius muscle) also leads to tissue-preserving fixation of

Electrode always micro-traumatic interventions in the filigree structures.

Long-term effects on interactions and interactions between the electrodes and the traumatized muscle tissue or bone structures are unknown. Occurring biofilm on the electrode surfaces of the stapedius muscle electrodes has a long-term unfavorable effect on the electrical properties of the contact surfaces. This can lead to inaccurate measurements of electrical activity. The external electrical measurement over various types of electrodes of the prior art is unreliable. Furthermore, in the prior art, the automatic adjustment process as a whole is described. It remains open how the sensor is designed to inject a signal. The use of mini magnets in addition to the round magnet used in the cochlear implant for attachment of the external speech processor also leads to considerable problems in the measurement of the physiological activities in an electrically evoked stapedius muscle tissue. The object of the invention is to determine the physiological activity of an electrically evoked tissue (stapedius muscle) by a non-contact detection or measurement, thereby avoiding the disadvantages of the prior art.

According to the invention, the object is achieved by a measuring device for non-contact mechanoelectrical measurement and monitoring of physiological activities in an electrically evoked staped lymph muscle tissue (eKEHRT sensor) for setting and calibrating cochlear implants, wherein the measuring device consists of a biocompatible sensor element (1) connected to or on or around a mobile structure in the middle ear cavity with a corresponding one

Fastener (4) is arranged and connected via a discharge electrode (5) with a cochlear implant, not shown. The round magnet (6) used in the cochlear implant for attaching the external speech processor is used to generate a magnetic field, wherein an additional sensor attached to or in the lead-off electrode (5) or mounted in a bone window in the middle ear cavity, the sensitivity of the sensor element (1 ) and an adjustment of the sensor element (1) facilitating miniature coil (7) is arranged.

In one embodiment of the invention, the sensor element (1) as a

biocompatible measuring electrode (2) or be designed as a biocompatible Hall sensor (3).

The sensor element (1) and miniature coil (7) is formed in a further embodiment of the invention as a biocompatible measuring electrode (2), wherein the

Sensor element (1) on the ossicular chain (long anvil limb, Stapek ankle) may be arranged.

The arrangement of the sensor element (1) and miniature coil (7) can also be reversed, in which case the sensor element (1) in the bone window and the miniature coil (7) can be fastened to the ossicular chain.

The sensor element (1) can be implemented in one-dimensional (1 D) or two-dimensional (2D) or three-dimensional (3D).

The invention will now be explained in more detail, wherein Fig. 1 is a schematic

Illustration of the measuring device shows and

1 sensor element 2 biocompatible measuring electrode

3 biocompatible Hall sensor

4 fastening element

5 discharge electrode

6 Round magnet of the cochlear implant, not shown

7 mini coils

mean.

The electrically evocable tissue (stapedius muscle) is connected to the ossicular chain via a tendon. The sensor element (1) in the form of a biocompatible Hall sensor (3) is arranged on or on a movable structure in the cavity of the middle ear, in particular on the ossicular chain (long anvil limb, stapes bones) with a corresponding fastening element (4) and allows accurate measurement of physiological activity. The

Sensor element (1) can be designed one-dimensional (1 D) or two-dimensional (2D) or three-dimensional (3D). The sensor element (1) is attached to the ossicle chain with a clinically proven titanium tab as a fastening element (4) and connected to an additional lead electrode (5) to the existing intracochlear electrode support with a cochlear implant, not shown. The multi-dimensionality of the sensor element (1) facilitates the adjustment in tight spaces in the middle ear. In the currently established design of the

Cochlear implants is a round magnet (6) for attaching the external

Speech processor already part of the system and is used to generate a magnetic field. An additional mini coil (7), on or in the

Ableitelektrode (5) integrated or mounted in a bone window in the middle ear cavity, increases the sensitivity of the Hall sensor (3) crucial and allows easier adjustment of the sensor element (1). Changes in the position of the ossicle chain or of the sensor element (1) are detected as an alternating signal. The leakage voltage (5) of the Hall voltage for the mechanoelectric measurement of the stapedius reflex (ESRT) is additionally arranged on the cochlear implant and can be used as active feedback for the control of the speech processor. The inventive solution also includes a modification of

Mounting locations. The miniature coil (7) will be on or around or around the moving ossicular chain and the Hall sensor (3) will be located in an additional bone window attached. The detection of the physiological activity of electrically evoked

Tissue, which is located in the middle ear of humans, is done by a non-contact measurement. It is an indirect measure of stapedial muscle activity. Compared to the prior art, the

Measuring device with respect to the object to be measured Stapedius muscle atraumatic attached and is suitable for long-term monitoring. It can be used as a physiological feedback signal for the objective control of a cochlear implant. The Hall sensor (3) operates without contact, is very sensitive to changes in the magnetic field and allows a better detection of the movement of the ossicular chain than with electrical or optical conduction. Of the

Characteristic curve is almost linear in the near field range. The small dimensions allow optimal positioning in the cavum of the middle ear. The

Measuring device can be in a correspondingly robust and wear-free

biocompatible envelope without time limit remain in the patient. The

The formation of a biofilm has no influence on the functionality.

Fundamental advantage of the measurement with a Hall sensor (3) is based on the change in the Hall voltage due to a relative movement of the Hall element in the magnetic field of a miniature coil. Both components are not directly connected mechanically. This reduces measurement errors. Both the evoked stapedius muscle and the stapedius tendon become indirect in this

Measurement method not directly contacted. For one, both are opposite

Manipulations are very sensitive and on the other hand, the contraction triggering Stapedius muscle is surgically difficult to access. The atraumatic methods for attachment of both components in the middle ear (Hall sensor, mini coil) can be adopted from clinically established procedures. It is irrelevant whether the Hall element (3) or alternatively the miniature coil (7) is attached to the movable middle ear structures. The decisive factor is a relative movement between the two

Components. In the first possible arrangement, the Hall element (3) on the long anvil limb and the miniature coil would be fixed firmly in the cavity of the middle ear. In the second possible arrangement, the mini-coil with the movable

Connected to the ossicle chain and the Hall element firmly attached in the cavity of the middle ear.

The invention has extensive economic potential. Intraoperative ESRT measurement to confirm correct insertion of the implantable electrode carrier for the intracochlear electrodes could be objectified by using automatic test procedures. This would reduce the necessary duration of surgery. In case of uncooperative patients and children possible overstimulation can be avoided. By establishing

Automatic adjustment mechanisms reduce the number of postoperative fitting appointments required for highly skilled personnel. The forecasts of the manufacturers of cochlear implants show a strong increase in demand in the coming years.

Claims

claims

1. Measuring device for non-contact mechanoelectric measurement and monitoring of physiological activities in an electrically evoked

Stapedius muscle tissue (eKEHRT sensor) for setting and calibrating cochlear implants, consisting of a biocompatible

Sensor element (1), wherein the biocompatible sensor element (1) arranged on or on or around a movable structure in the cavity of the middle ear with a corresponding fastening element (4) and via a

Ableitelektrode (5) is connected to the cochlear implant, not shown, and in the cochlear implant for attachment of the external

Speech processor used round magnet (6) for generating a

Magnetic field is used, characterized in that an additional on or in the Ableitelektrode (5) integrated or mounted in a bone window in the middle ear cavity, the sensitivity of the sensor element (1) increasing and an adjustment of the sensor element (1) facilitating miniature coil (7), is arranged.

2. Measuring device according to claim 1, characterized in that the

Sensor element (1) as a biocompatible measuring electrode (2) or as a biocompatible Hall sensor (3) is configured.

3. Measuring device according to claim 1 to 2, characterized in that the sensor element (1) and miniature coil (7) is designed as a biocompatible measuring electrode (2)

4. Measuring device according to claim 1 to 3, characterized in that the sensor element (1) on the ossicle chain (long anvil limb,

Stapesknöchelchen) is arranged.

5. Measuring device according to claim 1 to 4, characterized in that the arrangement of the sensor element (1) and miniature coil (7) are reversed, so the sensor element (1) in the bone window and the miniature coil (7) on the

Ossicle chain are attached.

6. Measuring device according to claim 1 to 5, characterized in that the sensor element (1) one-dimensional (1 D) or two-dimensional (2D) or three-dimensional (3D) is executed.