A transcranial electrical stimulation electrode for reducing the current density at the electrode edge

Abstract

The present invention discloses a transcranial electrical stimulation electrode for reducing the edge current density of the electrode. The transcranial electrical stimulation electrode is composed of a columnar conductive material and an insulating material, wherein a plurality of columnar conductive materials are coaxially nested from the inside to the outside, and each columnar conductive material in the same electrode is isolated by an insulating material, and the height of each columnar conductive material increases from the inside to the outside. The innermost layer of columnar conductive material is a solid columnar or a hollow columnar, and other columnar conductive materials except the innermost layer are hollow columns. The present invention changes the height of the inner and outer layers of columnar conductive materials, adjusts the impedance of the path where each point of the scalp contact surface is located to match it, and realizes the balance of the edge current density of each columnar body and the scalp contact surface, thereby reducing the edge current density of the electrode-scalp contact surface. Thereby reducing the side effects caused by excessive edge current density, providing a possible technical means for higher stimulation current amplitude.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical devices, and more specifically, relates to a transcranial electrical stimulation electrode for reducing the current density at the electrode edge. Background Art

[0002] Transcranial Electrical Stimulation (tES) is a non-invasive neurostimulation technology. According to different current forms, it can be divided into: Transcranial Direct Current Stimulation (tDCS), Transcranial Alternating Current Stimulation (tACS), and Transcranial Random Noise Stimulation (tRNS). The principle of transcranial electrical stimulation is to transmit a specific, low-intensity current (-2 to +2 mA, and more than 2 mA is only used for scientific research) from the scalp to a specific brain area, thereby generating an electric field of a specific amplitude in a specific area, and by regulating neuronal potentials, changing brain neuronal activity, and regulating cortical excitability, it can achieve the purpose of regulating mental disorders such as anxiety and depression and improving decision-making cognitive ability. At the same time, transcranial electrical stimulation is widely used in the treatment of diseases such as stroke rehabilitation, chronic pain and epilepsy. Transcranial electrical stimulation has the advantages of being non-invasive, safe and low-cost, and is expected to become an auxiliary means of drug and surgical treatment.

[0003] Key parameters such as stimulation current amplitude and electrode shape topology are important factors affecting the effect of direct current stimulation. There are many studies on stimulation electrode topology at home and abroad, but there is a lack of research on electrode shape. Figure 1 As shown, the conventional electrode adopts the following structure: a metal or rubber electrode is underlayed with a hydrogel, conductive rubber or a sponge electrode with a conductive solution (circular or square structure). However, this electrode will cause the current density at the edge of the electrode-scalp interface to be too large. This is because the conductivity and area on both sides of the electrode and brain contact surface are inconsistent, which in turn causes the impedance values ​​of the current paths at various points on the contact surface to be inconsistent. Since the impedance value of the path where each point on the edge of the contact surface is located is less than the resistance value of the path where each point on the other part of the contact surface is located, the current density at the edge of the electrode-scalp contact surface is too large. According to relevant studies, excessive current density can cause some side effects during stimulation, such as skin burns, redness, swelling, tingling and other side effects. Therefore, reducing the excessive current density at the edge of the electrode-skin contact surface is a problem that needs to be solved urgently for transcranial electrical stimulation. Summary of the invention

[0004] In view of the defects of the prior art, the object of the present invention is to solve the technical problem of excessive current density at the edge of the electrode-scalp contact surface during transcranial electrical stimulation in the prior art.

[0005] To achieve the above-mentioned purpose, an embodiment of the present invention provides a transcranial electrical stimulation electrode that reduces the current density at the edge of the electrode, wherein the transcranial electrical stimulation electrode is composed of a columnar conductive material and an insulating material, wherein a plurality of columnar conductive materials are coaxially nested from the inside to the outside, and the columnar conductive materials in the same electrode are isolated by insulating materials, and the height of each columnar conductive material increases from the inside to the outside, the innermost layer of columnar conductive material is a solid column or a hollow column, and the other columnar conductive materials except the innermost layer are all hollow columns.

[0006] Specifically, the solid columnar conductive material is a cylinder, a cube, an elliptical column or other irregular columnar bodies; the hollow columnar conductive material is correspondingly a hollow cylinder, a hollow cube, a hollow elliptical column or other hollow irregular columnar bodies.

[0007] Specifically, the number of the columnar conductive materials is 2 to 20.

[0008] Specifically, the columnar conductive material is a sponge with conductive liquid, conductive hydrogel or conductive rubber.

[0009] Specifically, the lateral distance between adjacent columnar conductive materials is inversely proportional to the conductivity of the material and inversely proportional to the conductivity of the scalp.

[0010] Specifically, the height difference between adjacent columnar conductive materials is proportional to the material conductivity, inversely proportional to the scalp conductivity, and proportional to the lateral distance between adjacent columnar conductive materials.

[0011] In general, the above technical solution conceived by the present invention has the following beneficial effects compared with the prior art:

[0012] The present invention changes the height of the inner and outer columnar conductive materials, adjusts the impedance of the paths at each point of the scalp contact surface to match them, achieves balanced edge current density at the contact surface between each column and the scalp, and reduces the edge current density at the electrode-scalp contact surface. This reduces the side effects caused by excessive edge current density and provides a possible technical means for higher stimulation current amplitude. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the three-dimensional structure of a traditional circular electrode;

[0014] Figure 2 A schematic diagram of a three-dimensional structure of a transcranial electrical stimulation electrode for reducing the current density at the electrode edge provided by an embodiment of the present invention;

[0015] Figure 3A vertical cross-sectional view of a transcranial electrical stimulation electrode for reducing the current density at the electrode edge provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0017] like Figure 2 As shown, a transcranial electrical stimulation electrode for reducing the current density at the edge of the electrode, the transcranial electrical stimulation electrode is composed of a columnar conductive material and an insulating material, wherein a plurality of columnar conductive materials are coaxially nested from the inside to the outside, and each columnar conductive material in the same electrode is isolated by an insulating material, and the height of each columnar conductive material increases from the inside to the outside, the innermost layer of columnar conductive material is a solid column or a hollow column, and the other columnar conductive materials except the innermost layer are all hollow columns.

[0018] The solid columnar conductive material 1 is a cylinder, a cube, an elliptical column or other irregular columns. The hollow columnar conductive material 2 is correspondingly a hollow cylinder, a hollow cube, a hollow elliptical column or other hollow irregular columns.

[0019] The number of the columnar conductive materials is 2 to 20.

[0020] The columnar conductive material is a sponge, conductive hydrogel or conductive rubber with conductive liquid. The lateral distance 3 (equal to the thickness of the insulating material) between adjacent columnar conductive materials is determined by the material conductivity and the scalp conductivity, and is inversely proportional to the material conductivity and inversely proportional to the scalp conductivity. The height difference 4 between adjacent columnar conductive materials is determined by the material conductivity, the scalp conductivity and the lateral distance 3, and is proportional to the material conductivity, inversely proportional to the scalp conductivity, and proportional to the lateral distance.

[0021] like Figure 3 As shown, compared with the solid cylinder 1, the distance between the hollow cylinder 2 and the other electrode of the opposite polarity on the scalp is closer, so the impedance value between its contact surface and the electrode of the opposite polarity is smaller. Similarly, compared with the hollow cylinder 2, the distance between the solid cylinder 1 and the other electrode of the opposite polarity on the scalp is farther, so the impedance value between its contact surface and the electrode of the opposite polarity is larger. If the height is not modulated, when 1 and 2 are energized in parallel, the current of 2 will be greater than the current of 1, and under the same electrode area, the contact surface current of cylinder 2 will be larger.

[0022] The transcranial electrical stimulation electrode designed by the present invention for reducing the current density at the electrode edge utilizes the height difference of each cylinder to adjust the impedance value of the cylinder to reduce the current density at the electrode edge. The present invention adjusts the height difference between cylinders 1 and 2 so that the taller 2 has a higher electrode impedance and the shorter 1 has a lower electrode impedance. The final effect is to match the total path impedance (the sum of the electrode impedance and the contact surface to the opposite polarity electrode impedance) of cylinders 1 and 2, thereby achieving the same current in each path and reducing the current density of each outer electrode.

[0023] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A transcranial electrical stimulation electrode that reduces the current density at the electrode edge, It is characterized in that The transcranial electrical stimulation electrode is composed of a columnar conductive material and an insulating material, wherein a plurality of columnar conductive materials are coaxially nested from the inside to the outside, and each columnar conductive material in the same electrode is isolated by an insulating material, and the height of each columnar conductive material increases from the inside to the outside, and the innermost layer of columnar conductive material is a solid columnar or a hollow columnar, and the other columnar conductive materials except the innermost layer are all hollow columns; Among them, the lateral distance between adjacent columnar conductive materials is inversely proportional to the conductivity of the material and inversely proportional to the conductivity of the scalp; The height difference between adjacent columnar conductive materials is proportional to the material conductivity, inversely proportional to the scalp conductivity, and proportional to the lateral distance between adjacent columnar conductive materials.

2. The transcranial electrical stimulation electrode according to claim 1, It is characterized in that The solid columnar conductive material is a cylinder, a cube, an elliptical column or other irregular columnar bodies; the hollow columnar conductive material is correspondingly a hollow cylinder, a hollow cube, a hollow elliptical column or other hollow irregular columnar bodies.

3. The transcranial electrical stimulation electrode according to claim 1, It is characterized in that The number of the columnar conductive materials is 2 to 20.

4. The transcranial electrical stimulation electrode according to claim 1, It is characterized in that The columnar conductive material is a sponge with conductive liquid, conductive hydrogel or conductive rubber.

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