Earplug electrode assembly capable of self-adapting to irregular morphology of ear canal and preparation method of earplug electrode assembly

Abstract

The invention relates to the field of medical detection equipment, in particular to an earplug electrode assembly capable of self-adapting to irregular morphology of an ear canal and a preparation method of the earplug electrode assembly, and is used for solving the problem that the signal quality is influenced due to limited intervention depth, too narrow positioning range and long distance between the electrode and a signal source of the existing earplug electrode. The electrode assembly provided by the scheme comprises a hollow conduit, a valve and an electrode, the electrode is attached to the outer wall of the catheter, an electrode signal detection area is communicated with an inner cavity of the catheter, and a valve is arranged at the tail end of the catheter; the electrode can be expanded as required according to different ear canal sizes. The interface instability of the auditory meatus electrode is improved through improvement of materials and a preparation process and reasonable structural design, auditory meatus discomfort is relieved, and the accuracy of electroencephalogram and cochlear electricity detection is improved.

Description

Technical Field

[0001] This case involves the field of medical testing equipment, and in particular, involves an earplug electrode assembly that can adapt to the irregular shape of the ear canal and a preparation method thereof. Background Art

[0002] External auditory canal electrodes have broad application prospects in auditory canal electroencephalogram detection and cochlear electroencephalogram detection.

[0003] Existing ear canal electrodes are often supported by earplugs or 3D printed accessories. The hard, non-deformable bracket cannot deform along the ear canal. It is difficult for such a non-deformable bracket to fit perfectly with the irregular inner wall of the ear canal, which often leads to poor local interface contact stability between the electrode and the ear canal, which not only affects the signal transmission quality and reduces the accuracy of EEG and cochlear electrical detection, but may also generate unstable signals due to poor contact, bringing difficulties to data analysis and diagnosis.

[0004] The ear canal is not a straight tube structure, and the depth of insertion of existing earplugs or bracket-type ear canal electrodes into the ear canal is limited. However, for EEG or cochlear electroencephalography, the closer the distance between the electrode and the detection site, the more accurate the detected signal. The limited intervention distance will affect the accuracy of EEG and cochlear electroencephalography signals, which may not accurately reflect the actual activity state of the brain and cochlea, thereby affecting the diagnosis and treatment of the disease. During the insertion and removal process, the strong friction between the bracket and the sensitive ear canal will irritate or even inflame the ear, increasing the patient's pain and discomfort. Summary of the invention

[0005] This case proposes a new ear canal electrode assembly, which aims to improve the problem of unstable interface contact between the electrode and the ear canal and limited electrode signal quality. In addition, through scientific and reasonable structural design, the ear canal electrode in this case can effectively alleviate the ear canal discomfort caused by wearing the electrode.

[0006] An earplug electrode assembly that can adapt to the irregular shape of the ear canal, the electrode is an isotropically stretchable flexible electrode, the area expansion rate of the electrode is less than or equal to 6, and can expand on demand according to different ear canal sizes; the electrode is integrated into the outer wall of the catheter, its signal detection area is connected to the inner cavity of the catheter, the electrode detection point faces outward, and the part outside the effective functional area of ​​the electrode is encapsulated with an insulating layer; a valve is installed at the tail end of the catheter, and the control valve can inflate the hollow catheter.

[0007] In the above technical solution, the overall appearance of the earplug electrode assembly is small and natural, and has little impact on daily activities during carrying and use. The hollow structure of the catheter can enhance people's perception of the surrounding environment. The valve is controlled to achieve inflation or exhaust of the catheter lumen and the electrode signal detection area. Since the electrode base has a smaller Young's modulus than the hollow catheter, the valve is inflated and deflated to enable the electrode signal detection area to achieve a conversion from the minimum compressible volume to a fully filled and expanded state. The earplug electrode assembly is tubular when it is at the minimum compressible volume. At this time, inserting and removing it from the ear canal can avoid friction and compression on the sensitive ear canal. When the earplug electrode assembly is in a fully filled and expanded state, it is spherical. At this time, collecting signals can increase the interface contact stability between the electrode and the ear canal to obtain qualified electrophysiological signals. The diameter of the sphere can be adjusted as needed according to ear canals of different sizes and shapes, and has stronger universality. Since the depth of the ear canal electrode inserted into the external auditory canal can be flexibly adjusted, it can be as close to the signal source as possible, which has obvious advantages over the previous earplug ear canal electrodes. When the area expansion rate of the electrode is 6, it still has good conductivity.

[0008] In one implementation of the above technical solution, the number of electrode channels is 1 to 100. Under the condition of ensuring good contact between the electrode and the ear canal, the comprehensiveness and accuracy of signal acquisition can be improved by changing the number and position of the electrodes.

[0009] In one implementation of the above technical solution, the electrode signal detection area is distributed on the catheter with a length of 1 cm to 2 cm.

[0010] In one embodiment of the above technical solution, the conductive layer material of the electrode is any one of the following: silver nanowires, gold nanowires, viscoelastic electrodes, gel electrodes, liquid metals. The above electrodes not only have good isotropic tensile properties, but also ensure their electrical conductivity as the electrode signal detection area changes from tubular to spherical.

[0011] In one implementation of the above technical solution, the electrode substrate and the insulating layer material are silicone film or water-based polyurethane film.

[0012] In one implementation of the above technical solution, an endoscope or a sound donor is integrated into the hollow portion of the catheter.

[0013] The preparation process of the ear canal electrode comprises the following steps: using a hot melt extrusion method to prepare an ear canal electrode having a Young's modulus in the range of 10 MPa-100 MPa silicone is extruded into a catheter with a hollow structure, and then the catheter is cooled and shaped; laser drilling is used in the electrode signal detection area and the valve installation area of ​​the cooled and shaped catheter; a patterned gold nanowire conductive layer is deposited on the filter membrane by combining filtration and mask plate, and then a layer of silicone is spin-coated, and vacuumization and oven curing are performed in sequence, and then the complex of gold nanowires and silicone is released from the filter membrane to obtain an electrode; the part outside the effective functional area of ​​the electrode is encapsulated with an insulating layer of silicone; the electrode is attached to the outer wall of the catheter by using a silicone adhesive, and it is ensured that the signal detection area of ​​the electrode is connected to the inner cavity of the catheter, and the electrode detection point faces outward; a valve is installed at the tail of the catheter, and the connection part is sealed, and the inflation and deflation of the inner cavity of the catheter and the electrode signal detection area are realized by controlling the valve, so as to adjust the morphology of the electrode signal detection area, so that the earplug electrode can adapt to external auditory canals of different sizes and shapes; according to actual use requirements, an endoscope or a sound giver is integrated in the hollow part of the catheter.

[0014] It can be seen from the above process that the part of the earplug electrode assembly in the external auditory canal is all made of soft material, which will not cause discomfort and damage when entering the external auditory canal, can be easily inserted and pulled out, and can be placed in a wide range of positions, not just limited to the ear canal opening. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0016] Figure 1 , one Schematic diagram of an earplug electrode assembly that can adapt to the irregular shape of the ear canal in one embodiment.

[0017] Figure 2 , one A schematic diagram showing the comparison of the isotropic deformation of the flexible stretchable electrode covering the entire hollow catheter with different inflation volumes in the embodiment.

[0018] Figure 3 , one Schematic diagram of the deformation of the flexible stretchable electrode when inflated in a single channel attachment manner in one embodiment.

[0019] Figure 4 , oneThe relationship between the area expansion rate and resistance of the flexible stretchable electrode and the inflation amount of the valve in this embodiment.

[0020] Figure 5 , one A diagram of EEG signals collected by the four-channel earplug electrode prepared in the embodiment in the ear canal of an adult, wherein the horizontal axis unit is seconds (S) and the vertical axis unit is millivolts (mV).

[0021] In the figure, 1 is the electrode detection point, 2 is the electrode signal detection area, 3 is the hollow catheter, 4 is the endoscope / sound giver, 5 is the insulating layer, and 6 is the valve. DETAILED DESCRIPTION

[0022] EEG detection is of great significance in the fields of medical diagnosis and scientific research. It is an important means of diagnosing various brain diseases such as epilepsy, encephalitis, brain tumors, cerebrovascular diseases, etc. It is also a key source of information for exploring brain cognitive functions, neural mechanisms and neural plasticity. Brain-computer interface technology can also convert EEG signals into control signals to achieve direct interaction between the human brain and external devices. EEG monitoring is usually divided into two types: invasive and non-invasive. Invasive EEG monitoring has certain limitations in clinical promotion due to its high risk. Non-invasive EEG detection avoids the infection risk of implanted electrodes and is widely accepted by the public. It has significant advantages in scientific research and daily medical care. In order to achieve good interface contact with the scalp, the EEG electrode cap commonly used in non-invasive EEG detection often needs to be coated with conductive paste, and the subjects are required to remove their hair. The preparation and cleaning process are relatively cumbersome. In recent years, the ear canal EEG electrode mentioned has attracted widespread attention for its unique wearability and convenience, and has been verified and applied in sleep monitoring, brain function assessment and other aspects. Existing ear canal EEG electrodes are usually supported by earplugs or 3D printed accessories to ensure good contact between the electrode and the inner wall of the ear canal. Although the prospects are broad, there are still some common problems such as limited electrode channels and unstable interface contact.

[0023] The electrocochlear electrogram is a set of response waves emitted by the cochlea after sound stimulation, including cochlear microphonics (CM), summating potentials (SP) and action potential (AP). It is the I wave of auditory evoked potentials and an important basis for studying the function of inner ear hair cells and the conduction mechanism of auditory nerves. Clinically, the electrocochlear electrogram is an important means to assess the degree and nature of hearing loss, and is also an important basis for the diagnosis of inner ear diseases such as Meniere's disease and middle ear lesions. The recording electrodes used in the electrocochlear electrogram examination are often placed on the tympanic membrane or promontory of the person being examined, or inserted into the subcutaneous part of the external auditory canal. The operation is cumbersome, and during the placement of the electrode, the tympanic membrane is easily damaged due to improper operation, which brings certain risks to the person being examined. Another commonly used cochlear electrophysiological examination electrode in clinical practice is similar to an earplug and is placed at the entrance of the ear canal. Due to its distance from the cochlea and only one detection point, the quality of the measured signal is limited and it is difficult to meet the needs of refined evaluation, which to some extent affects the accurate diagnosis and in-depth research of the disease.

[0024] As a key component for monitoring electroencephalogram (EEG) and cochlear electrophysiology, ear canal electrodes play a vital role in the quality of monitoring signals and user experience. However, existing ear canal electrodes have many problems, such as poor interface contact stability, narrow positioning range, discomfort to users during insertion and removal, and limited detection channels. Therefore, there are still huge challenges in material selection and preparation processes to develop more comfortable ear canal electrodes and achieve more stable and accurate monitoring of physiological electrical activity.

[0025] Based on this, this case proposes an earplug electrode assembly that can adapt to the irregular shape of the ear canal, which can be used to collect physiological electrical signals from the ear canal. Through the improvement of materials and preparation processes as well as reasonable structural design, many problems existing in the existing ear canal electrodes, such as poor interface contact stability, narrow positioning range, and limited number of channels, are solved. The interface instability of the electrode is improved, the discomfort in the ear canal is alleviated, and the accuracy of EEG and cochlear electrical detection is improved.

[0026] The following will be combined with the accompanying drawings to clearly and completely describe how to implement the technical solution of this case. Obviously, the described implementation method is only a part of the implementation method of this case, not all of the implementation methods. Based on the implementation method in this case, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] Figure 1The structure of an earplug electrode assembly suitable for monitoring ear canal EEG and / or cochlear electroencephalogram is shown. The electrode assembly includes a hollow catheter 3, an electrode signal detection area 2 connected to the inner cavity of the hollow catheter 3, a plurality of electrodes 1 evenly distributed along the circumference of the catheter, and an endoscope / sound giver 4 integrated at the center of the hollow catheter 3.

[0028] The electrode signal detection area is located at the head end of the hollow catheter. The electrode conductive layer is integrated on the outer wall of the hollow catheter, and the electrode signal detection area is connected to the catheter lumen. The catheter lumen and the electrode signal detection area are inflated or deflated by controlling the valve 6, so that the electrode signal detection area can achieve the conversion from the minimum compressible volume to the fully filled and expanded state.

[0029] The diameter of the electrode signal detection area can be adjusted as needed according to different sizes and shapes of ear canals, which has stronger applicability and can adapt to external auditory canals of different sizes and shapes. The maximum expandable diameter of the electrode signal detection area is no greater than the diameter of the external auditory canal; the minimum compressible volume is less than the volume when it is fully inserted into the external auditory canal.

[0030] Figure 2 The diagram shows the comparison of the isotropic deformation of the flexible stretchable electrode when it covers the entire hollow conduit with different inflation volumes. The portion outside the effective functional area of ​​the electrode is encapsulated by an insulating layer 5.

[0031] The flexible stretchable electrode is attached by a single channel. Under the condition of ensuring good contact between the electrode and the ear canal, the comprehensiveness and accuracy of signal acquisition can be improved by changing the number and position of the electrodes. The number of electrode channels can be determined according to the measurement accuracy of the signal, and the number can range from 1 to 100. Through the following preparation method, electrode channels of 1, 2, 3, 4, 5, 6, etc. can be designed. When the number of electrode channels is 1, it is a single-channel ear canal electrode. When the number of electrode channels is 2, it is a dual-channel ear canal electrode. When the number of electrode channels is greater than or equal to 3, it is a multi-channel ear canal electrode. When a single channel attachment method is adopted, it is inflated and deformed as shown in the figure. Figure 3 As shown, Figure 3 Four flexible stretchable electrodes are used, and the signal detection area of ​​each flexible stretchable electrode is connected to the inner cavity of the catheter.

[0032] The materials of the insulating layer and the electrode substrate are high molecular polymers with high isotropic stretchability, such as silicone film, water-based polyurethane film, etc., so that the insulating layer and the electrode substrate can be deformed as needed. The material of the electrode conductive layer is a material that can be prepared with high isotropic stretchable conductivity, such as silver nanowires, gold nanowires, viscoelastic electrodes, gel electrodes, liquid metals, etc., so that the electrode has good isotropic stretchable conductivity. Not only can the morphology be deformed with the inflation and deflation of the catheter lumen, but also its electrical conductivity is guaranteed when it changes from tubular to spherical. When the area expansion rate is as high as 6, it still maintains good electrical conductivity, see Figure 4 .

[0033] The electrode processing method includes scraping method, suction filtration method, etc. The electrode thickness can be 0.01-1 mm.

[0034] When the electrode assembly is in use, the valve is controlled to inflate or exhaust the inner cavity of the catheter and the electrode signal detection area, so that the signal detection area can achieve the conversion from the minimum compressible volume to the fully filled and expanded state. Therefore, the shape of the electrode signal detection area can be freely converted between tubular and spherical, so that the depth of the ear canal electrode inserted into the external auditory canal can be flexibly adjusted to be as close to the signal source as possible, which has obvious advantages over the previous earplug-type ear canal electrodes. When the ear canal electrode is in a tubular shape, it can be easily inserted into or removed from the external auditory canal. At this time, since it is in an unexpanded state, it will not cause friction or pressure to the ear canal during the insertion and removal process. When it is pushed to a specific position in the external auditory canal, it can be expanded into a spherical state by inflation, thereby achieving a close interface fit between the electrode and the external auditory canal, thereby having excellent anti-motion interference capabilities, while also ensuring that the electrode and the ear canal have good contact resistance characteristics, and obtaining qualified electrophysiological signals.

[0035] The hollow structure of the hollow catheter can be used to place an endoscope or a sound giver 4 as needed. The endoscope can assist the electrode in achieving precise positioning, and the sound giver can provide sound stimulation to the eardrum during cochlear electrical monitoring. When the hollow structure is in an empty state, it can significantly reduce the shielding effect of the electrode on external sounds, improving people's perception of the surrounding environment.

[0036] The earplug electrode has a small and natural overall appearance and has little impact on daily activities during carrying and use. The preparation method thereof includes the following steps.

[0037] S10. A hot melt extrusion method is used to extrude silicone with a Young's modulus in the range of 10 MPa-100 MPa into a hollow conduit with a hollow structure, and then the hollow conduit is cooled and formed to maintain the stability of its shape and size.

[0038] S20. Use laser drilling to drill holes at specific locations of the hollow conduit, such as the area that needs to be covered by the electrode signal detection part, the valve installation area, etc.

[0039] S30, a patterned gold nanowire conductive layer is deposited on the filter membrane by combining filtration and mask plate, and then a layer of Ecoflex 50 silicone is spin-coated, vacuuming for 20 minutes and curing in an oven at 60°C, and then the composite of gold nanowires and silicone is released from the filter membrane to obtain a flexible and stretchable composite electrode with high isotropic tensile conductivity. The electrode thickness is 0.01-1mm. Exemplarily, four channel electrodes are distributed along the circumference of the catheter, and the effective functional area of ​​the electrode is in the form of a circular sheet.

[0040] S40. After sticking PI tape on the effective functional area of ​​the electrode, spin-coat a thin layer of Ecoflex 50 silicone at a speed of 2000-5000rpm with a thickness of about 10-30um. Gently peel off the PI tape and cure the thin silicone layer. The part outside the effective functional area of ​​the electrode is encapsulated with an insulating layer.

[0041] S50. Use silicone adhesive to attach the electrode to the outer wall of the catheter, and ensure that the signal detection area of ​​the electrode is connected to the inner cavity of the catheter, and the electrode detection point faces outward.

[0042] S60. Install the valve at the tail end of the hollow conduit and seal the connection.

[0043] In one embodiment, the prepared four-channel earplug electrode is placed in the external auditory canal of an adult to measure the EEG signal. Figure 5 As shown in the figure, it can be seen that the electrode can effectively collect human brain electrical signals in the external auditory canal. In the experiment, the prepared earplug electrode obtained a stable alpha wave brain electrical signal when the eyes were closed.

[0044] In summary, in response to many problems of existing ear canal electrodes, such as the limited number of channels, poor interface contact stability, and too narrow positioning range, this case proposes an earplug electrode assembly that can adapt to the external auditory canal morphology for ear canal EEG or cochlear electrical monitoring and its preparation method. Among them, the hollow structure of the hollow core catheter in the assembly can enhance people's perception of the surrounding environment, and an endoscope or sound donor can be placed as needed. The electrode signal detection area can realize free conversion between tubular and spherical shapes, so that the depth of the ear canal electrode sent into the external auditory canal can be flexibly adjusted, and it can be as close to the signal source as possible, which has obvious advantages compared with the previous earplug ear canal electrodes. When it is tubular, sending it into and out of the ear canal can avoid friction and pressure on the sensitive ear canal. When it is spherical, collecting signals can increase the interface contact stability between the electrode and the ear canal, and the diameter of the sphere can be adjusted as needed according to ear canals of different sizes and different morphologies, which has stronger adaptability. The electrode conductive layer is integrated on the hollow catheter, and the signal detection area of ​​the electrode is connected to the inner cavity of the catheter. The morphology of the electrode detection point can change synchronously with the inflation and deflation of the valve at the tail end of the catheter. The electrode conductive layer adopts nanowire electrodes, gel electrodes, viscoelastic electrodes, liquid metals, etc. with large isotropic tensile conductivity, which ensures its electrical conductivity as the signal detection area changes from tubular to spherical.

[0045] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments and application fields, which are merely illustrative and instructive, rather than restrictive. A person skilled in the art can make many forms under the guidance of this specification and without departing from the scope of protection of the claims of the present invention, all of which are protected by the present invention.

Claims

1. An earplug electrode assembly that can adapt to the irregular shape of the ear canal, characterized in that: The electrode assembly includes a hollow catheter, a valve, and an electrode; The electrode is a unidirectional stretchable flexible electrode that can expand as needed according to different ear canal sizes; The electrode is integrated into the outer wall of the catheter, and its signal detection area is connected to the inner cavity of the catheter. The electrode detection point faces outward, and the part outside the effective functional area of ​​the electrode is encapsulated with an insulating layer; The catheter has a valve at the end.

2. The earplug electrode assembly according to claim 1, characterized in that: The number of electrode channels is 1-100.

3. The earplug electrode assembly according to claim 1, characterized in that: The electrode signal detection area is distributed over a length of 1 cm to 2 cm on the catheter.

4. The earplug electrode assembly according to claim 1, characterized in that: The conductive layer material of the electrode is any one of the following: silver nanowire, gold nanowire, viscoelastic electrode, gel electrode, liquid metal.

5. The earplug electrode assembly according to claim 1, characterized in that: The electrode substrate and the insulating layer are made of silicone film or water-based polyurethane film.

6. The earplug electrode assembly according to claim 1, characterized in that: The area expansion rate of the electrode is less than or equal to 6.

7. The earplug electrode assembly according to claim 1, characterized in that: An endoscope or a sound transmitter is integrated into the hollow part of the catheter.

8. A method for preparing an earplug electrode assembly, characterized in that: The method comprises the following steps: Using hot melt extrusion, silicone with a Young's modulus in the range of 10-100 MPa is extruded into a catheter with a hollow structure, and then the catheter is cooled and shaped; For the cooling and shaping conduit, laser drilling is used in the area that needs to be covered by the electrode signal detection part and the valve installation area; Install a valve at the end of the conduit and seal the connection; The patterned electrodes were prepared on silicone substrates with a Young's modulus ranging from 0.01 to 1 MPa using a combination of masking and metal deposition. The portion outside the effective functional area of ​​the electrode is encapsulated with an insulating layer of silicone; The electrode is attached to the outer wall of the catheter using a silicone adhesive, and the signal detection area of ​​the electrode is ensured to be connected to the inner cavity of the catheter, and the electrode detection point faces outward.

9. The preparation method according to claim 8, characterized in that: When preparing the electrode, the conductive layer material of the electrode is any one of the following: silver nanowire, gold nanowire, viscoelastic electrode, gel electrode, liquid metal.

10. The preparation method according to claim 8, characterized in that: An endoscope or a sound transmitter is integrated into the hollow part of the catheter.

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