JP6873079B2 - Artificial hearing device - Google Patents

Description

The present invention relates to an artificial hearing device arranged in a cochlea.

An artificial hearing device that is used by embedding it in the cochlea, which forms part of the inner ear, has been proposed. This artificial auditory device converts the sound wave reaching the inner ear into an electric signal by a piezoelectric film arranged in the cochlea, and the electric signal generated by a plurality of microelectrodes installed on the piezoelectric film is converted into an electric signal in the cochlea. It is configured to be transmitted directly to the auditory nerve as an electrical stimulus (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2014-45937

By the way, when an artificial auditory device is placed in the cochlea and an auditory nerve stimulating electrode, which is a minute electrode, is to be implanted in the cochlea or the cochlea, a film-like piezoelectric layer that converts sound waves into electrical signals. Since the structure in and around it is very thin, it may be damaged by the pressure and load of the electrode pushing.

An object of the present invention is to provide a highly reliable embedded artificial hearing device in which damage such as cracks and cracks does not occur in the sound resonance portion including the piezoelectric layer at the time of implantation in the cochlea. Is.

The artificial auditory device of the present disclosure is an artificial auditory device that converts sound waves that reach the cochlea of the inner ear into electrical signals and transmits them to the auditory nerve.
With separable cochlear implants and sonic resonances,
The cochlear implant includes an electrode for stimulating the auditory nerve, a first substrate that supports the electrode, and a first terminal portion that is disposed at one end of the first substrate and is electrically connected to the electrode. , Including
The sound wave resonance unit is electrically connected to a second substrate having a predetermined unique frequency, a conversion unit that converts the vibration of the second substrate into an electric signal, and the conversion unit, and the first unit. Includes a second terminal that can be engaged with one terminal
The cochlear planting portion is embedded in the inner wall of the cochlea so that the first terminal portion projects toward the inside of the cochlea (tympanic floor).
The sound wave resonance portion is characterized in that the second terminal portion is engaged with the first terminal portion and is arranged inside the cochlea (tympanic duct).

According to the present disclosure, it is possible to obtain a highly reliable artificial hearing device in which the sound wave conversion part and the sound wave resonance part are not damaged even when the cochlea is implanted.

(A) and (b) show the state before the connection of the cochlear implant part and the sound wave resonance part in the artificial hearing device of embodiment, (a) is the top view, and (b) is the sectional view in the vertical direction. (C) and (d) show the state after the cochlear planting portion and the sound wave resonance portion are connected, (c) is a top view, and (d) is a vertical sectional view. It is a figure which shows the engagement state of the 1st terminal part of the cochlear planting part with the 2nd terminal part of a sound wave resonance part, (a) shows the state before fitting, (b) shows the state after fitting. It is a figure which shows the example which fitted the other 1st terminal part with a different shape into a 2nd terminal part. It is a top view which shows the other shape example of the engaging recess formed in the 2nd terminal part of a sound wave resonance part. It is a figure explaining the procedure of arranging the artificial hearing device of an embodiment in a cochlea, (a) shows the state after embedding a cochlea embedding part, and (b) shows the state after mounting a sound resonance part. It is a figure explaining the procedure of disposing the other artificial hearing device of an embodiment in a cochlea, (a) shows the state after embedding a cochlea embedding part, and (b) shows the state after mounting a sound wave resonance part. .. It is a figure which shows the configuration example of the artificial hearing device which has the guide part which guides the approach of the 2nd terminal part to the 1st terminal part. It is a figure which shows the structural example of the artificial hearing device which has the guide member which guides the approach of the 2nd terminal part to the 1st terminal part. (A) is a cross-sectional view which shows the outline of the structure of an ear, and (b) is the cross-sectional view which shows the outline of the structure of a cochlea.

The basic configuration of the artificial hearing device described in the present embodiment is shown in the figure before the connection of FIGS. 1 (a) and 1 (b) and the figure after the connection of FIGS. 1 (c) and 1 (d). As shown, it is composed of two blocks, that is, a combination of two parts or fractions. That is, the artificial auditory device of the present embodiment selects a combination of the cochlear implant portion 1 which is an example of the electrode portion for stimulating the auditory nerve and the sound wave resonance portion 2 of various shapes that converts sound waves into electric signals. It is possible, and the cochlear planting portion 1 and the sound wave resonance portion 2 are connected so as to be engageable, detachable, or interchangeable. Each layer constituting the cochlear planting portion 1 in the figure, including each layer of the sound wave resonance portion 2 described later, is drawn with emphasis on its thickness.

As shown in FIG. 1, the cochlear planting portion 1 is composed of a first substrate 11 that also serves as a substrate or a substrate, a conductor layer 13 that is an electrode for stimulating acoustic nerves, and a first substrate 11 and a conductor layer 13. The insulator layer 12 arranged between the insulator layer 12 and one end portion of the first substrate 11, that is, the first terminal portion 10 arranged on the right side in the drawing and on the inner side of the cochlea and connected to the conductor layer 13 which is an electrode. And, including. The configuration of the cochlear planting portion as described above is an example in the present disclosure, and may be a first substrate that also serves as one or both of the conductor layer and the insulator layer. For example, if the first substrate is made of a conductor, it is not necessary to provide an insulator layer, and the first substrate serves both as a substrate and an electrode.

As shown in the figure, the first substrate 11 has, for example, a wedge shape having a tapered tip in a plan view, and has a thickness and rigidity to withstand pushing into the cochlear wall surface and implantation. The first substrate 11 includes a pointed tip 11a and a wedge-spread base end 11b on the axial or longitudinal direction opposite to the tip 11a, from the tip 11a side to the inner wall of the cochlea. It is pushed into and buried.

As the constituent material of the first substrate 11, among metals, inorganic substances, resins and the like, those having the above-mentioned rigidity are preferably used. For example, in the case of metal, gold (Au), platinum (Pt) and the like can be mentioned. As for inorganic substances, silicon (Si), silicon oxide (SiO ₂ ), SOI (Silicon on Insulator), glass, ceramics and the like can be used. As the resin, resins such as acrylic resin, fluororesin, polyimide resin, epoxy resin, polyparaxylene resin, polyphenylene sulfide (PPS) resin, and acrylonitrile-butadiene-styrene (ABS) resin can be used. The first substrate 11 in FIG. 1 is made of silicon (Si).

The conductor layer 13 is an electrode for stimulating the auditory nerve, and is made of a metal film such as gold (Au) or platinum (Pt) formed on the surface of the insulator layer 12 by vapor deposition or the like.

Further, the insulator layer 12 electrically insulates between the first substrate 11 and the conductor layer 13 constituting the electrode, and silicon oxide (SiO ₂ ) formed by a CVD method or the like is used. It is composed of an oxide film containing or an insulating film such as a nitride film containing silicon nitride (SiN).

The first terminal portion 10 is provided integrally with the first substrate 11. The shape is formed in a columnar or cylindrical shape such as a prism, a cylinder, etc., which is on the right side of the drawing and projects outward from the inner side of the cochlea from the wedge-shaped base end portion 11b of the first substrate 11. Has been done. Then, the first terminal portion 10 is formed into a shape that can be fitted and engaged with the second terminal portion 20, which is a concave engaged portion provided on the sound wave resonance portion 2 and the second substrate 22, which will be described later. ing.

Further, as shown in the cross-sectional view of FIG. 1B, the first terminal portion 10 includes a first base 11 which is a support member, a conductor layer 13 which serves as a terminal electrode, and a first terminal portion 10, similarly to the cochlear planting portion 1. 1 It is composed of an insulator layer 12 disposed between the substrate 11 and the conductor layer 13. Among them, the conductor layer 13 is connected to the conductor layer 13 on the side of the first substrate 11 on the left side of the figure on the inner wall side of the cochlea, and the end face on the right side of the figure on the inner side of the cochlea and the terminal on the lower surface following it. It extends to the back surface 10a of the part.

As a result, as shown in FIG. 1D, the first terminal portion 10 is fitted into and engaged with the second terminal portion 20, which is a concave engaging portion provided on the sound resonance portion 2 and the second base 22. Or, when fitted, it is electrically connected to the surface electrode layer 27, which is a terminal electrode on the sound resonance portion 2 side, which extends into the concave second terminal portion 20.

The sound resonance unit 2 is electrically connected to the second base 22 having a predetermined unique frequency, the conversion unit 21 that converts the vibration of the second base 22 into an electric signal, and the conversion unit 21. It is composed of a second terminal portion 20 that can be engaged with the first terminal portion 10 described above, and an adjusting weight portion 21a for adjusting the resonance frequency, which is arranged under the second base 22.

The frequency of the sound resonance portion 2 as a whole, which resonates and resonates with the sound wave with respect to the natural frequency or the natural frequency of each member, is called a "resonance frequency". Further, the configuration of each layer such as the sound wave resonance portion as described above and the piezoelectric layer described later is an example in the present disclosure, and the configuration is omitted by allowing each configuration to concurrently serve two or more functions. It can also be configured simply. For example, if quartz or the like is used as the piezoelectric body, it is possible to use at least two or more of the second substrate, the conversion unit, and the second terminal unit as one member.

The conversion unit 21 is formed by laminating a plurality of functional layers on a flat plate-shaped second substrate 22 as a substrate or a substrate. That is, as shown in the cross-sectional views of FIGS. 1 (b) and 1 (d), the conversion unit 21 has the oxide film layer 23 and the insulator layer 24 on the surface of the second substrate 22 on the upper surface side of the drawing. The back surface electrode layer 25, the piezoelectric layer 26, and the front surface electrode layer 27 are sequentially laminated and formed.

The second base 22 has a flat plate shape as shown in the figure, and like the first base 11, is made of a metal, an inorganic substance, a resin, or the like having rigidity as a constituent material. The constituent material is, for example, a resin such as gold (Au) or platinum (Pt) for a metal, silicon (Si) for an inorganic substance, silicon oxide (SiO ₂ ), SOI (Silicon on Insulator), glass or ceramics, etc. If so, acrylic resin, fluororesin, polyimide resin, epoxy resin, polyparaxylene resin, polyphenylene sulfide (PPS) resin, acrylonitrile-butadiene-styrene (ABS) resin and the like can be used. The second base 22 in FIG. 1 is made of silicon (Si).

The oxide film layer 23 is an oxide layer formed by heat-treating the second base 22, and is formed on the surface side of the second base 22 which is the upper surface side in the drawing. The oxide film layer 23 on the front surface side of the second substrate 22 functions as an insulating layer that electrically insulates the back surface electrode layer 25 and the second substrate 22. _{As described above, the oxide film layer 23 is made of silicon oxide (SiO 2} ) formed by heat-treating the second base 22 when the second base 22 is made of silicon (Si).

The oxide film layer 23 is also formed on the back surface side of the second substrate 22, which is the lower surface side shown in the drawing. The oxide film layer 23 on the back surface side of the second substrate 22 functions as an etching mask (etching stop layer) when forming the second substrate 22.

The insulator layer 24 electrically insulates between the second substrate 22 and the piezoelectric layer 26 described later, and like the above-mentioned insulator layer 12, silicon oxide (silicon oxide) formed by a CVD method or the like. It is _{composed of an oxide film containing SiO 2} ) or an insulating film such as a nitride film containing silicon nitride (SiN). The insulator layer 24 is formed on the left and right sides of the piezoelectric layer 26 described later.

The back surface electrode layer 25 and the front surface electrode layer 27 are arranged so as to sandwich the piezoelectric layer 26 described later above and below, and like the above-mentioned conductor layer 13, gold (Au) or gold (Au) formed by vapor deposition or the like. It is composed of a metal film such as platinum (Pt). Among them, the surface electrode layer 27 located on the upper surface of the outermost surface of the conversion portion 21 is a second terminal portion 20 on the left side of the drawing and on the inner wall side of the cochlea and a recess 20a which is a concave engaging portion formed therein. It extends to the inside.

The piezoelectric layer 26 is a film-like layer made of a piezoelectric material that generates an electric charge due to the piezoelectric effect when curved. As the piezoelectric material, barium titanate, lead zirconate titanate, polyvinylidene fluoride or the like is used.

The conversion unit 21 having the above configuration has a predetermined resonance frequency that resonates and resonates with the sound wave that has arrived in the cochlea.

The adjusting weight portion 21a arranged on the lower side of the second substrate 22 is provided to adjust the resonance frequency of the above-mentioned conversion portion 21. The adjusting weight portion 21a is formed of, for example, a solid rectangular parallelepiped using silicon (Si), glass, ceramics, or the like. The second terminal portion 20 and the adjusting weight portion 21a may be made of the same material, or may be made of different materials. If the second terminal portion 20 and the adjusting weight portion 21a are made of the same material, for example, silicon (Si) and have the same thickness, they can be formed at once by Si deep digging (dry etching), which simplifies the processing process.

The shape, size, mass, and the like of the adjusting weight portion 21a are appropriately set according to the target resonance frequency. Further, the adjusting weight portion 21a does not have to be provided.

Next, as described above, the second terminal portion 20 includes a recess 20a that engages with the first terminal portion 10 of the cochlear planting portion 1. Like the first base 11 and the second base 22, the second terminal portion 20 is made of a metal, an inorganic substance, a resin, or the like having rigidity as a constituent material. The second terminal portion 20 of FIG. 1 is configured by using silicon (Si).

The groove-shaped recess 20a provided on the base end side of the second terminal portion 20, that is, on the left side in the drawing and on the inner wall side of the cochlea, is a groove-shaped recess 20a as shown in the cross-sectional views of FIGS. 2A and 2B. An extension portion of the surface electrode layer 27 described above is arranged on the bottom surface 20c of the recess. Further, on the inner wall surface 20b of the concave portion 20a, an engaging convex portion 20d which is a concave inner convex portion capable of engaging with the terminal portion step portion 10b (see FIG. 2) provided on the side surface of the first terminal portion 10 is provided. It is formed.

As a result, as shown in FIGS. 1 (d) and 2 (b), when the first terminal portion 10 of the cochlear planting portion 1 is fitted into the recess 20a of the second terminal portion 20 of the sound wave resonance portion 2. The engaging convex portion 20d described above can engage with the terminal portion step portion 10b to firmly fix the first terminal portion 10. Further, by the above engagement, the conductor layer 13 which is one terminal electrode arranged on the back surface 10a of the terminal portion of the first terminal portion 10 is provided on the bottom surface 20c of the recess of the second terminal portion 20, the other. Since the surface electrode layer 27, which is the terminal electrode of the above, is abutted against and pressed against the extended portion, the electrical conduction between them can be ensured.

The groove shape and the cross-sectional shape of the engaging recess 20a of the second terminal portion 20 are not particularly limited to the shapes of FIGS. 1 and 2. Further, the outer shape of the first terminal portion 10 of the cochlear planting portion 1 on the engaged side that engages with the engaging recess 20a may be appropriately changed according to the shape of the engaging recess 20a. Further, the concave convex portion may be formed on the opposite side, that is, the concave portion for engagement may be formed on the first terminal portion 10 side, and the convex portion for engagement may be formed on the second terminal portion 20 side. ..

For example, as shown in FIG. 3, the first terminal portion 10'may have a size so that the entire portion can be accommodated in the groove shape of the engaging recess 20a. Even with the shape of the first terminal portion 10', the conductor layer 13 on the back surface 10a of the terminal portion is formed by the engagement between the first terminal portion 10'and the second terminal portion 20 as in the previous example. Since it is pressed against the surface electrode layer 27 of the above, reliable electrical continuity can be ensured.

Further, for example, as shown in the upper view of the groove-shaped recess 20a for engagement in FIG. 4, the opening edge portion of the recess 20a on the first terminal portion 10 side, that is, the left side of the drawing and the inner wall side of the cochlea is enlarged. It may be tapered to open. As a result, the first terminal portion 10 can be easily fitted into the second terminal portion 20'. As a result, reliable electrical continuity between the first terminal portion 10 and the second terminal portion 20'can be ensured.

Next, a method of burying and arranging the artificial hearing device of the embodiment including the cochlear implanting portion 1 and the sound wave resonance portion 2 described above in the cochlea will be described.

First, the basic structure of the ear in which the artificial hearing device is arranged is shown in FIG. 9 (a), and the basic structure of the cochlea of the inner ear is shown in FIG. 9 (b). In these basic ear structures, the names of the respective parts are designated by reference numerals, and detailed description of each configuration is omitted.

In FIG. 9A, the ear, which is a sensory organ that controls hearing, is divided into an outer ear 100, a middle ear 200, and an inner ear 300. The sound wave generated outside the ear is guided from the ear canal 101 to the eardrum 102 and vibrates the eardrum 102, and the sound wave vibration is transmitted to the inside of the cochlea 301 through the ossicle 201.

The cochlea 301 is tubular with about two and a half turns. As shown in FIG. 9B, the interior is divided into three regions, the vestibular floor 302, the central floor 303, and the scala tympani floor 304, and each region is filled with lymph. The vestibular floor 302 and the central floor 303 are separated by the Ricenell membrane 305, and the central floor 303 and the scala tympani floor 304 are separated by the basement membrane 306.

The basement membrane 306 is vibrated by the propagating sound wave, and the inner hair cells 307 on the basement membrane 306 are bent by the vibration. The inner hair cells 307 are deformed by the relative movement with the tectorial membrane 308 to cause a potential fluctuation. In each part of the cochlea 301, the bundles of spiral ganglion cells 309, which are stimulated acoustic ganglia with potential fluctuations, transmit the electrical signals generated in the cochlea 301 to the brain, and when they reach the cerebral cortex, they vary. It is recognized as a complex sound having various frequency components.

FIG. 5 is a diagram showing an example in which the artificial auditory device having the above-described configuration is installed in the cochlea 301 in parallel with the basement membrane 306, and FIG. 6 is a diagram showing an example in which the artificial auditory device having the above-described configuration is installed in the cochlea 301 and the basement membrane 306. It is a figure which shows the example which installed perpendicular to the cross section of the membrane 306 and scala tympani 304.

As shown in FIGS. 5 and 6, when the artificial auditory device of the embodiment is installed in the scala tympani 304 of the cochlea 301, in any case, first, the artificial auditory device is embedded in the cochlea outside the cochlea 301. It is separated into a plant portion 1 and a sound wave resonance portion 2. Among them, the cochlear implant 1 is inserted into the cochlea 301, and the pointed tip 11a of the wedge-shaped cochlear implant 1 is passed through the inner wall of the cochlea 301 from the inside of the scala tympani 304 to the spiral ganglion cell 309. It is inserted toward the auditory ganglion, which is a bundle, and the cochlear implant portion 1 is embedded up to the vicinity of the proximal end portion 11b for implantation. At this time, the degree of embedding is the state shown in FIGS. 5 (a) and 6 (a), that is, the degree to which the first terminal portion 10 of the cochlea burial portion 1 projects into the cochlea 301 from the inner wall of the cochlea 301. To do.

Next, the sound resonance portion 2 is inserted into the same cochlea 301, and the recess 20a of the second terminal portion 20 of the sound resonance portion 2 is inserted into the first terminal portion 10 of the cochlea implant portion 1 that has been implanted earlier. By fitting the first terminal portion 10 closer to each other and engaging the terminal portion step portion 10b of the first terminal portion 10 with the engaging convex portion 20d inside the concave portion 20a, the cochlea planting portion 1 and the sound resonance portion in the cochlea 301 Installation with 2 where electrical continuity is ensured can be completed.

By the way, conventionally, when trying to dispose a similar artificial hearing device in the cochlea, the artificial hearing device is an integral type in which the cochlear implanting part and the sound wave resonance part are inseparable and inseparable. At the time of implantation, unnecessary pressure and load due to the electrode pushing were applied to the sound wave resonance part, and the sound wave resonance part may be cracked, bent, or damaged.

On the other hand, in the artificial hearing device of the present embodiment, since the cochlear implant portion 1 and the sound resonance portion 2 can be separated, the cochlea resonance portion 2 is moved to the cochlea when the load-bearing cochlea implant portion 1 is pushed. By removing it from the buried portion 1, it is possible to prevent the sound resonance portion 2 from being damaged without applying an extra force. Therefore, the artificial hearing device of the present embodiment can be a highly reliable artificial hearing device in which the sound wave conversion unit 21 and the sound wave resonance unit 2 are not damaged even when implanted in the cochlea. it can.

In addition, in order to facilitate the attachment of the sound wave resonance part 2 to the cochlea planting part 1 in the scala tympani 304 of the cochlea 301 described above, a second is attached to at least one of the cochlea planting part 1 and the sound wave resonance part 2. A guide portion may be provided to guide the terminal portion 20 to approach the first terminal portion 10. Alternatively, a guide member for guiding the approach of the second terminal portion 20 to the first terminal portion 10 may be provided.

FIG. 7 shows an example of the configuration of the guide portion, and FIG. 8 shows an example of the configuration of the guide member.

The artificial hearing device shown in FIG. 7 includes a guide portion 14 extending from the cochlear planting portion 1 in the vicinity of the first terminal portion 10. The guide portion 14 is formed by extending a part of the first substrate 11 in the same direction as the protrusion direction of the first terminal portion 10, and as shown in the figure, one end of the sound wave resonance portion 2 is a guide portion. By abutting against 14, the sound wave resonance portion 2 can be positioned. With this configuration, the sound wave resonance portion 2 can be easily attached to the cochlear planting portion 1 even in a place where there is not enough space, such as in the scala tympani floor.

In the artificial hearing device shown in FIG. 8, a guide member 30 is attached in advance to the cochlear implanting portion 1 after being implanted in the cochlea. Further, a guide ring 31 is attached to the sound wave resonance portion 2, and by inserting the guide ring 31 into the rod-shaped portion of the guide member 30, it is possible to move the sound wave resonance portion 2 along the guide member 30. It is said. The groove shape of the engaging recess 20a of the second terminal portion 20'in the sound wave resonance portion 2 is a tapered shape in which the first terminal portion 10'side is greatly opened as shown in FIG. Further, the first terminal portion 10'of the cochlear planting portion 1 also has a thin shape as shown in FIG.

Even with this configuration, in places where there is not enough space, such as inside the scala tympani floor, the second terminal portion 20'approaches and fits into the first terminal portion 10', that is, the cochlear implant portion of the sound resonance portion 2. The attachment to 1 can be easily performed.

The size and shape of the cochlear planting portion 1 and the sound wave resonance portion 2 shown in the above embodiments, particularly the planar shape, are merely examples, and any of the other ones can be adjusted according to the frequency of the sound wave to be received or received. It can be changed to such a shape. Further, the arrangement angle and direction of the artificial hearing device in the cochlea are not limited to the examples of FIGS. 7 and 8, and can be appropriately set.

Further, the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the gist of the present invention.

1 Cochlear planting part 10, 10'1st terminal part 11 1st base 13 Conductor layer (electrode for nerve stimulation)
14 Guide part 2 Sound wave resonance part 20, 20'Second terminal part 20a Recessed part 21 Conversion part 21a Adjusting weight part 22 Second base 26 Piezoelectric layer 30 Guide member 31 Guide ring

Claims (4)

An artificial auditory device that converts sound waves that reach the cochlea of the inner ear into electrical signals and transmits them to the auditory nerve.
With separable cochlear implants and sonic resonances,
The cochlear implant includes an electrode for stimulating the auditory nerve, a first substrate that supports the electrode, and a first terminal portion that is disposed at one end of the first substrate and is electrically connected to the electrode. , Including
The sound wave resonance unit includes a second substrate having a unique frequency, a conversion unit that converts the vibration of the second substrate into an electric signal, and the first terminal unit that is electrically connected to the conversion unit. Includes an engageable second terminal
The cochlear planting portion is embedded in the inner wall of the cochlea so that the first terminal portion projects toward the inside of the cochlea.
The sound wave resonance portion is an artificial hearing device arranged inside the cochlea by engaging the second terminal portion with the first terminal portion. The artificial hearing device according to claim 1, wherein the conversion unit includes a piezoelectric layer. The artificial hearing device according to claim 1 or 2, wherein at least one of the cochlear implant portion and the sound wave resonance portion includes a guide portion that guides the approach of the second terminal portion to the first terminal portion. The artificial hearing device according to claim 1 or 2, further comprising a guide member for guiding the approach of the second terminal portion to the first terminal portion.

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