Earplug electrode assembly capable of adapting to irregular ear canal morphology and preparation method thereof

Abstract

This case involves the field of medical detection equipment, and in particular, an earplug electrode assembly that can adapt to the irregular shape of the ear canal and its preparation method, which is used to solve the problem that existing earplug electrodes affect signal quality due to limited insertion depth, too narrow positioning range, and long distance between the electrode and the signal source. The electrode assembly proposed in this solution includes a hollow catheter, a valve, and an electrode; the electrode is attached to the outer wall of the catheter, and the electrode signal detection area is connected to the inner cavity of the catheter. The tail end of the catheter is equipped with a valve; the electrode can expand as needed according to different ear canal sizes. Through improvements in materials and preparation processes and reasonable structural design, the interface instability of the ear canal electrode can be improved, ear canal discomfort can be alleviated, and the accuracy of EEG and cochlear electroencephalography detection can be improved.

Description

Technical Field

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

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

[0003] Existing ear canal electrodes are often supported by earplugs or 3D-printed accessories. The rigid, non-deformable bracket cannot deform compatibly along the ear canal. This non-deformable bracket is difficult to fully fit the irregular inner wall of the ear canal, which often leads to poor local interface contact stability between the electrode and the ear canal. This not only affects the signal transmission quality and reduces the accuracy of EEG and cochlear electroencephalography 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 insertion depth of existing earplug or bracket-type ear canal electrodes into the ear canal is limited. However, for EEG or cochlear electroencephalography (EEG) testing, the closer the electrode is to the detection site, the more accurate the detected signal. This limited insertion distance affects the accuracy of EEG and cochlear electroencephalography signals, potentially failing to accurately reflect the true activity of the brain and cochlea, thereby affecting the diagnosis and treatment of diseases. During insertion and removal, the strong friction between the bracket and the sensitive ear canal can cause irritation and even inflammation of the ear, increasing pain and discomfort for the patient. Summary of the Invention

[0005] This case proposes a new ear canal electrode assembly designed to address issues such as unstable contact between the electrode and the ear canal and limited electrode signal quality. Furthermore, through a scientific and rational structural design, this ear canal electrode effectively alleviates ear canal discomfort associated with wearing the electrode.

[0006] An earplug electrode assembly that can adapt to the irregular shape of the ear canal. The electrode is a uniformly stretchable flexible electrode with an area expansion rate of less than or equal to 6, which can meet the needs of expanding 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. 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 earbud electrode assembly has a compact and natural appearance, minimizing impact on daily activities during portability and use. The hollow structure of the catheter enhances awareness of the surrounding environment. A valve is controlled to inflate and deflate the catheter lumen and electrode signal detection area. Because the electrode base has a smaller Young's modulus than the hollow catheter, inflation and deflation of the valve allow the electrode signal detection area to transition from a minimum compressible volume to a fully inflated and expanded state. At its minimum compressible volume, the earbud electrode assembly is tubular, allowing insertion and removal from the ear canal to avoid friction and pressure on the sensitive ear canal. When fully inflated and expanded, the earbud electrode assembly assumes a spherical shape, enhancing signal acquisition stability at the electrode-ear canal interface and obtaining qualified electrophysiological signals. The spherical diameter can be adjusted to accommodate ear canals of varying sizes and shapes, providing greater universality. Because the depth of insertion into the external auditory canal can be flexibly adjusted, this ear canal electrode can be placed as close to the signal source as possible, offering significant advantages over previous earbud-type ear canal electrodes. When the area expansion rate of the electrode is 6, it still has good conductivity.

[0008] In one embodiment of the above technical solution, the number of electrode channels is 1 to 100. Under the condition of ensuring good contact between the electrodes 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 embodiment 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, and 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 embodiment of the above technical solution, the electrode substrate and the insulating layer material are silicone film or water-based polyurethane film.

[0012] In one embodiment 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 above-mentioned ear canal electrode comprises the following steps: using a hot melt extrusion method to prepare a Young's modulus in the range of 10 MPa-100 MPa silicone is extruded into a hollow catheter, which is then cooled and shaped. Laser holes are drilled in the electrode signal detection area and valve installation area of the cooled and shaped catheter. A patterned gold nanowire conductive layer is deposited on the filter membrane using a combination of filtration and masking, followed by spin coating with a layer of silicone. Vacuuming and oven curing are performed in sequence, and the gold nanowire and silicone composite is then released from the filter membrane to obtain an electrode. 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, ensuring that the electrode signal detection area is connected to the inner lumen of the catheter, with the electrode detection point facing outward. A valve is installed at the tail of the catheter, and the connection is sealed. The valve is controlled to achieve inflation and deflation of the inner lumen of the catheter and the electrode signal detection area, thereby adjusting the morphology of the electrode signal detection area and enabling the earplug electrode to adapt to external auditory canals of different sizes and shapes. An endoscope or a sound giver is integrated into the hollow portion of the catheter according to actual usage requirements.

[0014] It can be seen from the above process that the part of the earplug electrode assembly inside the external auditory canal is all made of soft material, which will not cause discomfort or damage when entering the external auditory canal. It can be easily inserted and removed, 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 following briefly introduces the drawings required for use in the description of the embodiments. 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 any creative work.

[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 Schematic diagram of the comparison of the isotropic deformation of the flexible stretchable electrode when covering the entire hollow catheter with different inflation volumes in this embodiment.

[0018] Figure 3 、 one Schematic diagram of the deformation of the flexible stretchable electrode when inflated using a single channel attachment method in this embodiment.

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

[0020] Figure 5 、 one Graph of EEG signals collected by the four-channel earplug electrode prepared in the embodiment in the ear canal of an adult, where the horizontal axis is in seconds (S) and the vertical axis is in 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 insulation layer, and 6 is the valve. DETAILED DESCRIPTION

[0022] EEG monitoring is of great significance in both medical diagnosis and scientific research. It is an important tool for diagnosing a variety of brain diseases, including epilepsy, encephalitis, brain tumors, and cerebrovascular disease. It also provides a key source of information for exploring cognitive function, neural mechanisms, and neuroplasticity. Brain-computer interface technology can also convert EEG signals into control signals, enabling direct interaction between the human brain and external devices. EEG monitoring is generally categorized as invasive or non-invasive. Invasive EEG monitoring has limitations in clinical application due to its higher risk. Non-invasive EEG testing avoids the infection risks associated with implanted electrodes and is widely accepted by the public, offering significant advantages in scientific research and everyday healthcare. The EEG electrode caps commonly used in non-invasive EEG testing often require the application of conductive paste to ensure good contact with the scalp and require the subject to shave their hair, making preparation and cleaning processes cumbersome. In recent years, ear canal EEG electrodes have garnered widespread attention for their unique wearability and convenience, and have been validated and applied in sleep monitoring and brain function assessment. Existing ear canal EEG electrodes are usually supported by earplugs or 3D-printed accessories to ensure good contact between the electrodes and the inner wall of the ear canal. Although these electrodes have broad prospects, they still face some common problems such as limited electrode channels and unstable interface contact.

[0023] The electrocochlear electrogram (ECG) is a set of response waves emitted by the cochlea in response to sound stimulation. These waves include cochlear microphonics (CM), summing potentials (SP), and action potentials (AP). These waves are the I wave of auditory evoked potentials and are an important basis for studying inner ear hair cell function and auditory nerve conduction mechanisms. Clinically, ECG is an important tool for assessing the extent and nature of hearing loss and for diagnosing inner ear diseases such as Meniere's disease and middle ear lesions. The recording electrodes used in ECG examinations are often placed on the patient's tympanic membrane, promontory, or inserted subcutaneously into the external auditory canal. This cumbersome procedure also poses a significant risk to the patient by causing damage to the tympanic membrane due to improper placement of the electrodes. Another commonly used cochlear electrophysiological examination electrode in clinical practice is similar to an earplug and is placed at the opening of the ear canal. Due to its distance from the cochlea and the presence of only one detection point, the quality of the measured signal is limited, making it difficult to meet the needs of refined evaluation. This, to a certain 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 the user experience. However, existing ear canal electrodes suffer from numerous issues, including poor interface contact stability, a narrow positioning range, user discomfort during insertion and removal, and limited detection channels. Therefore, developing more comfortable ear canal electrodes for more stable and accurate physiological electrical activity monitoring still presents significant challenges in terms of material selection and fabrication processes.

[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 improvements in materials and preparation processes and reasonable structural design, it solves many problems existing in the existing ear canal electrodes, such as poor interface contact stability, narrow positioning range, and limited number of channels. It improves the interface instability of the electrode and alleviates ear canal discomfort, thereby improving the accuracy of EEG and cochlear electrical detection.

[0026] The following, combined with the accompanying drawings, provides a clear and complete description of how the technical solution of this case is implemented. Obviously, the described implementation methods are only part of the implementation methods of this case, not all of the implementation methods. Based on the implementation methods of this case, all other implementation methods obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0027] Figure 1The diagram illustrates the structure of an earplug electrode assembly suitable for monitoring ear canal EEG and / or cochlear electroencephalography. The electrode assembly comprises a hollow tube 3, an electrode signal detection area 2 connected to the inner lumen of the hollow tube 3, several electrodes 1 evenly distributed along the circumference of the tube, and an endoscope / sound injector 4 integrated into the center of the hollow tube 3.

[0028] The electrode signal detection area is located at the tip of the hollow catheter. The electrode conductive layer is integrated into the outer wall of the hollow catheter, and the electrode signal detection area is connected to the catheter lumen. By controlling valve 6, the catheter lumen and the electrode signal detection area are inflated or deflated, allowing the electrode signal detection area to transition from a minimum compressible volume to a fully inflated state.

[0029] The diameter of the electrode signal detection area can be adjusted to suit different ear canal sizes and shapes, providing greater adaptability and accommodating external auditory canals of varying shapes and sizes. The maximum expandable diameter of the electrode signal detection area is no larger than the external auditory canal diameter; the minimum compressible volume is less than the volume when 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 catheter with different inflation volumes. The portion outside the effective functional area of the electrode is encapsulated by the insulating layer 5.

[0031] The flexible stretchable electrode is attached in 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... and so on 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 lumen of the catheter.

[0032] The insulating layer and electrode substrate are made of polymers with high isotropic stretchability, such as silicone films, water-based polyurethane films, etc., allowing the insulating layer and electrode substrate to deform as needed. The conductive layer is made of materials that can be used to produce high isotropic stretchable conductivity, such as silver nanowires, gold nanowires, viscoelastic electrodes, gel electrodes, liquid metals, etc., which ensures that the electrode has good isotropic stretchable conductivity. Not only can the shape change with the inflation and deflation of the catheter lumen, but also the electrical conductivity is guaranteed when it changes from tubular to spherical. Even 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, filtration method, etc. The electrode thickness can be 0.01-1mm.

[0034] When the electrode assembly is in use, the valve is controlled to inflate or deflate the inner cavity of the catheter and the electrode signal detection area, so that the signal detection area can achieve a conversion from the minimum compressible volume to a 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. This 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. After being 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 good contact resistance characteristics between the electrode and the ear canal, and obtaining qualified electrophysiological signals.

[0035] The hollow structure of the hollow catheter allows for placement of an endoscope or a sound injector as needed. The endoscope assists in precise electrode positioning, while the sound injector provides sound stimulation to the eardrum during cochlear electroencephalography. When the hollow structure is empty, it significantly reduces the shielding effect of the electrodes on external sounds, enhancing a person's awareness of their surroundings.

[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 tube with a hollow structure, and then the hollow tube is cooled and shaped 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 using a combination of filtration and masking. A layer of Ecoflex 50 silicone is then spin-coated. The process is vacuumed for 20 minutes and then oven-cured at 60°C. The gold nanowire and silicone composite is then released from the filter membrane to produce a flexible, stretchable composite electrode with high isotropic tensile conductivity. The electrode thickness is 0.01-1 mm. For example, the catheter has four channel electrodes distributed along its circumference, and the electrode's effective functional area is in the form of a circular sheet.

[0040] S40. After affixing PI tape to the effective functional area of the electrode, spin-coat a thin layer of Ecoflex 50 silicone at a speed of 2000-5000 rpm, with a thickness of about 10-30 μm. 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 electrodes in the external auditory canal can effectively collect human brain electrical signals. In the experiment, the prepared earplug electrodes obtained stable alpha wave brain electrical signals when the eyes are 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 tube in the assembly can enhance people's perception of the surrounding environment, and an endoscope or sound injector 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 inserted into the external auditory canal can be flexibly adjusted and can be as close to the signal source as possible, which has obvious advantages compared with the previous earplug-type ear canal electrodes. Inserting and removing the ear canal in the tubular shape can avoid friction and pressure on the sensitive ear canal, and collecting signals in the spherical shape 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 shapes, 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 lumen 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 to ensure its electrical conductivity as the signal detection area changes from tubular to spherical.

[0045] Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the specific embodiments and application areas described above. The specific embodiments described above are merely illustrative and instructive, and not restrictive. A person skilled in the art, guided by this specification and without departing from the scope of protection of the claims of the present invention, may devise various other embodiments, 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 by: The electrode assembly includes a hollow catheter, a valve, and an electrode; The hollow conduit is extruded into a hollow structure using silicone, and the electrodes are attached and integrated onto the outer wall of the hollow conduit using silicone adhesive, with the electrode detection point facing outward, and the portion outside the effective functional area of the electrode is encapsulated with an insulating layer; A corresponding hole is provided in the electrode signal detection area of the hollow catheter, so that the electrode signal detection area is connected to the catheter lumen. A hole is provided at the tail end of the hollow catheter, and a valve is installed to realize the inflation or deflation of the hollow catheter lumen and the electrode signal detection area through the valve. The electrode is a unidirectionally stretchable flexible electrode, so that the electrode signal detection area can be expanded from a tubular shape to a spherical shape or converted from a spherical shape to a tubular shape as needed according to different ear canal sizes through inflation or deflation.

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

3. The earplug electrode assembly according to claim 1, wherein: 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, wherein: 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, wherein: The electrode base and the insulating layer are made of silicone film or water-based polyurethane film.

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

7. The earplug electrode assembly according to claim 1, wherein: 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 ranging from 10-100 MPa is extruded into a hollow tube, which is then 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 catheter and seal the connection; Patterned electrodes were fabricated 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 silicone adhesive, ensuring that the signal detection area of the electrode is 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 sound transmitter is integrated into the hollow part of the catheter.

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