Method for determining parameters of double-target time interference stimulation electrode and stimulation method

Abstract

The invention relates to a method for determining parameters of a double-target time interference stimulating electrode and a stimulating method. The method comprises the following steps of: inputting a lead field matrix, coordinates of two target spots and an electrode frequency; generating a random solution and multiplying the random solution with the lead field matrix to obtain a corresponding high-frequency electric field; inputting a Grossman formula, and obtaining two groups of envelope electric fields with frequencies of # imgabs0 # and delta fHz; performing Hilbert transform and space vector summation on the two groups of envelope electric fields to form a total matrix; constructing a target point matrix; solving the ratio of the average electric field intensity of the target spot matrix to the average electric field intensity of the total matrix, and if the ratio is less than b, removing a corresponding random solution; if the ratio is larger than b, the corresponding random solution is reserved, and a new random solution is generated; and iteration is carried out to a suspension condition, and if suspension is carried out, the reserved random solution is output. Through the arrangement, an electrode feasible solution for simultaneously stimulating double target spots through time interference stimulation can be effectively found.

Description

Technical Field

[0001] The present invention relates to the technical field of brain electrical stimulation, and in particular to a method for determining parameters of dual-target time interference stimulation electrodes and a stimulation method. Background Art

[0002] Temporal interferometric stimulation (TIS) is a type of transcranial electrical stimulation (TES). TES involves placing electrodes on the scalp and stimulating brain nuclei through discharges, thereby treating mental illness. It is non-invasive, has minimal side effects, and is highly effective. Conventional TES typically only effectively stimulates the cerebral cortex, while TIS leverages the low-pass filtering properties of cells to create an interference effect through two high-frequency electric fields with a difference frequency, generating a low-frequency envelope within the brain and effectively stimulating deep brain nuclei.

[0003] Transcranial electrical stimulation requires the arrangement of electrodes and the regulation of current to achieve the goal of focusing the electric field on the target nucleus. However, with temporal interferometric stimulation, since the stimulation targets deep nuclei, there is no intuitive connection between the electrode placement and the stimulation target. Moreover, when using four pairs of electrodes to stimulate two targets, the predicted electric field may differ significantly from the actual electric field because the electric fields generated by different pairs of electrodes may overlap, subtract, or interfere with each other.

[0004] Therefore, in the prior art, there is a lack of a method for determining the parameters of dual-target temporal interference stimulation electrodes to achieve accurate temporal interference stimulation of two target points. Summary of the Invention

[0005] In order to solve the above-mentioned defects, the present invention proposes a method for determining parameters of dual-target time interference stimulation electrodes and a stimulation method.

[0006] The technical solution adopted by the present invention is a method for determining parameters of dual-target time interference stimulation electrodes, the method comprising:

[0007] S100: Input the lead field matrix of the subject's head model, the coordinates of two target points, and the electrode frequency;

[0008] S200, generating a random solutions to form a random solution matrix, wherein the structure of the solution matrix is the electrode position and the corresponding current magnitude; a>1;

[0009] S300, multiplying the solution matrix by the lead field matrix to obtain a high-frequency electric field corresponding to each pair of electrodes;

[0010] S400, the electrode frequency of S100 and the high-frequency electric field corresponding to each pair of electrodes of S300 are input into the Grossman formula to obtain the frequency and 2 sets of envelope electric fields of ΔfHz; Δf is the frequency increment between two adjacent pairs of electrodes;

[0011] S500, performing Hilbert transform and space vector summation on the two sets of envelope electric fields obtained in S400 to form a total matrix;

[0012] S600, extracting and constructing a target point matrix from the total matrix in S500 according to the two target point coordinates in S100;

[0013] S700, calculating the ratio of the average electric field strength of the target matrix to the average electric field strength of the total matrix. If the ratio is less than b, the corresponding random solution is removed; if the ratio is greater than b, the corresponding random solution is retained and a new random solution is generated to form a new random solution; b>1;

[0014] S800 and S300-S700 constitute one iteration, and the termination condition of the iteration is:

[0015] The number of iterations reaches c, and / or

[0016] The ratio in S700 is greater than d, d>b;

[0017] If the termination condition is met, the random solution retained in S700 is output.

[0018] Preferably, the S500 specifically includes:

[0019] Substituting E1=cosπΔf and E2=cos 2πΔf into the Hilbert transform formula, the result is the fusion field equation of the two envelope fields E1 and E2 are two electric fields of dual-target temporal interference stimulation; the two sets of envelope electric fields obtained by S400 are vector-summed to obtain the electric field distribution in space; according to the fusion field equation And the electric field distribution in space is obtained to obtain the total matrix.

[0020] Preferably, the S200 generates a random solutions using a multi-objective optimization algorithm.

[0021] Preferably, the S700 generates a new random solution by using a multi-objective optimization algorithm, wherein the optimization objectives of the multi-objective optimization algorithm are: maximizing the average electric field intensity of the target matrix and minimizing the average electric field intensity of the total matrix.

[0022] Preferably, the multi-objective optimization algorithm is one of genetic algorithm, NSGA-II, MOVEA or particle swarm optimization.

[0023] Preferably, a≥80; b≥1.1; c≥150; d≥1.8.

[0024] Preferably, the step S600 extracts and constructs a target point matrix from the total matrix based on the two target point coordinates of the step S100, specifically including:

[0025] The second norm of the second dimension of the total matrix is calculated. According to the coordinates of the two target points in S100, a sphere with the target point as the center and a radius of r is found. The corresponding part of the sphere in the matrix is extracted to construct a new matrix, namely the target point matrix; 1.3 cm>r>0.8 cm.

[0026] The present invention also proposes a dual-target time interference stimulation method, which uses the electrode parameters determined by the above-mentioned method for determining the electrode parameters of the dual-target time interference stimulation to perform stimulation.

[0027] Preferably, the electrode frequency is ≥500 Hz, Δf ≤100 Hz, and the total current of all electrodes is ≤4 mA.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The method for determining the parameters of the dual-target temporal interference stimulation electrode proposed in the present invention alleviates the practical need for simultaneous stimulation of dual targets, can effectively find a feasible solution for the electrodes to simultaneously stimulate dual targets with temporal interference stimulation, and can ensure that the focusing of the electric field is greater than the threshold when stimulating deep nuclei such as the thalamus.

[0030] 2. According to the method of the present invention, the user only needs to input the lead field matrix, target coordinates, and electrode frequency. The program automatically undergoes multiple optimization iterations and finally provides accurate electrode arrangement and current parameters, thereby achieving accurate and efficient dual-target stimulation effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention is described in detail below with reference to the embodiments and accompanying drawings, in which:

[0032] Figure 1 This is a flow chart of a method for determining parameters of dual-target temporal interference stimulation electrodes;

[0033] Figure 2 This is the electric field simulation diagram. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the present invention more apparent, embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar components or components having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0035] This paper proposes a method for determining electrode parameters for dual-target temporal interferometric stimulation. This method, for temporal interferometric electrical stimulation, can generate several Pareto solutions within the effective timeframe, each of which effectively stimulates both targets. Each solution includes the coordinates of four (8) pairs of electrodes and the current magnitude of each pair, with the coordinates conforming to the MNI coordinate system.

[0036] In one embodiment, a method for determining parameters of a dual-target temporal interference stimulation electrode is described. Figure 1 , the method includes the following steps.

[0037] S100: Input the lead field matrix of the subject's head model, the coordinates of two target points, and the electrode frequency.

[0038] The lead field matrix has a size of M×N×3 (M is the number of electrodes, N is the number of head model grids, and 3 is the three directions in three-dimensional space). The lead field matrix represents the relationship between the electrode positions and the conductivity of the head model grids. The electrode frequency f is ≥ 500 Hz and Δf is ≤ 100 Hz. For example, f = 2000 Hz and Δf = 20 Hz.

[0039] S200. Generate a random solutions to form a random solution matrix. The solution matrix consists of electrode positions and corresponding current magnitudes; a > 1. Electrode positions are the coordinates of four pairs of electrodes (eight electrodes) (randomly selected from a preset set of 76 10-10 international standard lead positions). Current magnitude is the current value for each electrode pair, with the total current for all electrodes ≤ 4 mA. Electrode positions cannot be repeated, and current distribution must meet safety limits.

[0040] S300 , multiplying the solution matrix (electrode position+current) by the lead field matrix to obtain a high-frequency electric field corresponding to each pair of electrodes.

[0041] S400, the electrode frequency of S100 and the high-frequency electric field corresponding to each pair of electrodes of S300 are input into the Grossman formula to obtain the frequency and ΔfHz; Δf is the frequency increment between two adjacent pairs of electrodes.

[0042] Specifically, dual-target temporal interferometric stimulation uses four pairs of electrodes to discharge. Assuming the frequency of the first pair of electrodes is fHz, the frequency of the i-th pair of electrodes is (f+(i-1)Δf)Hz, where Δf is the frequency increment between two adjacent pairs of electrodes. Thus, we obtain the following electric field time-domain formula:

[0043] E=cosω1t+cosω2t+cosω3t+cosω4t#(1)

[0044] ω is the angular frequency of the electric field generated by a pair of electrodes, and t represents the time variable.

[0045] Let ω = 2πf and f i =f+(i-1)Δf is substituted into the formula (i=1,2,3,4) and simplified according to the trigonometric function formula to obtain:

[0046] E=cosπΔfcos 2πΔfcosπ(2f+3Δ…)#(2)

[0047] From the formula, we can see that there are three electric fields in the current space, with frequencies of and a low-frequency envelope field of ΔfHz and a frequency of high-frequency electric field.

[0048] From formula 2, we can see that these four groups of envelope fields are actually divided into two frequencies, namely and ΔfHz, so in calculation we take adjacent difference frequencies as a group. For example, the frequencies of electrode pair ABCD are 2000, 2020, 2040, and 2060, respectively. First, input the Grossman formula with AB and CD as a group, and you can get two low-frequency envelope fields with frequencies of 10 Hz ((2020-2000) / 2 and (2060-2040) / 2) and two high-frequency electric fields with frequencies of 2010 Hz ((2000+2020) / 2) and 2050 Hz ((2040+2060) / 2) respectively. These two high-frequency electric fields are then substituted into the Grossman formula to obtain a group of low-frequency electric fields with a frequency of 20 Hz ((2050-2010) / 2) and a group of high-frequency electric fields with a frequency of 2030 Hz ((2050+2010) / 2). Because high-frequency electric fields usually have little effect on the brain, we only focus on the two low-frequency envelope fields of 10 Hz and 20 Hz.

[0049] The Grossman formula is as follows:

[0050]

[0051] in, is the envelope electric field, is a space vector, is the electric field of the first set of electrodes, is the electric field of the second set of electrodes, α is The final result is the envelope space electric field distribution matrix of the temporal interference stimulus.

[0052] S500 , performing Hilbert transformation and space vector summation on the two sets of envelope electric fields obtained in S400 to form a total matrix.

[0053] By fusing the envelope field characteristics through the Hilbert transform in the time domain and combining it with the vector summation in space, the electric field information is comprehensively integrated from the time and space dimensions, laying the foundation for the subsequent extraction of the electric field matrix of the target area and the optimization of the electrode configuration, ultimately serving the precise focusing goal of dual-target temporal interference stimulation.

[0054] S600 , extracting and constructing a target point matrix from the total matrix in S500 according to the two target point coordinates in S100 .

[0055] S700. Calculate the ratio of the average electric field strength of the target matrix to the average electric field strength of the total matrix. If the ratio is less than b, remove the corresponding random solution. If the ratio is greater than b, retain the corresponding random solution and generate a new random solution to form a new random solution. b>1.

[0056] Specifically, the a random solutions generated in S200 will generate a group of total matrices and target target matrices respectively. Each group will divide the average value of the target target matrix by the average value of the total matrix, remove the solutions whose ratio is less than b, and supplement them with new random numbers to form a group of new solutions.

[0057] S800 and S300-S700 constitute one iteration, and the termination condition of the iteration is:

[0058] The number of iterations reaches c, and / or

[0059] The ratio in S700 is greater than d, d>b;

[0060] If the termination condition is met, the random solution retained in S700 is output.

[0061] The method for determining the parameters of dual-target time interference stimulation electrodes proposed in the present invention alleviates the practical need for simultaneous stimulation of dual targets, can effectively find feasible electrode solutions for simultaneous stimulation of dual targets, and can ensure that the focusing of the electric field is greater than the threshold when stimulating deep nuclei such as the thalamus.

[0062] According to the process of the above method, the user only needs to input the lead field matrix, target coordinates, and electrode frequency. The program will automatically go through multiple optimization iterations and finally provide accurate electrode layout and current parameters, thereby achieving accurate and efficient dual-target stimulation effects.

[0063] In one embodiment, Formula 2 is decomposed into a combination of three electric fields: e=cosπΔf, e=cos 2πΔF, and E=cosπ(2f+3Δf), where the first two are frequencies of and ΔfHz (i.e., 10 Hz, 20 Hz in the example of step S400), the latter being a high frequency electric field (i.e., 2030 Hz in the example of step S400).

[0064] Therefore, the S500 specifically includes:

[0065] Perform vector summation on the two sets of envelope electric fields obtained in S400 to obtain the electric field distribution in space; according to the fusion field equation The total matrix is obtained by combining the spatial electric field distribution and the low-frequency envelope fields of different frequencies. The final spatial electric field distribution is obtained by spatially superimposing them. This distribution reflects the comprehensive strength and direction of the electric field in three-dimensional space under dual-target temporal interference stimulation and is a key basis for evaluating the focusing effect of electrode configuration on the target.

[0066] Substituting E1=cosπΔf and E2=cos 2πΔf into the Hilbert transform formula, the result is the fusion field equation of the two envelope fields E1 and E2 are the two electric fields of the dual-target temporal interference stimulation. Through the Hilbert transform, the amplitude information of the envelope field is extracted, and the two independent envelope fields are fused into a single expression to characterize the comprehensive characteristics of the envelope field in the time domain, providing a basis for subsequent analysis of the change pattern of the electric field over time. Specifically, the Hilbert transform formula of S500 is: in H[■] is the Hilbert transform.

[0067] In one embodiment, the S200 generates a random solutions and adopts a multi-objective optimization algorithm. The multi-objective optimization algorithm can effectively handle large-scale multi-objective optimization problems.

[0068] In one embodiment, S700 generates new random solutions using a multi-objective optimization algorithm whose optimization objectives are to maximize the average electric field strength of the target matrix and minimize the average electric field strength of the total matrix. The results of the multi-objective optimization algorithm are several sets of new solutions that better meet the optimization objectives.

[0069] In one embodiment, the multi-objective optimization algorithm is a genetic algorithm, NSGA-II, MOVEA, or particle swarm optimization. For example, a genetic algorithm is a type of evolutionary algorithm that simulates natural selection and genetic mechanisms and searches for the optimal solution through selection, crossover, and mutation operations. NSGA-II handles multi-objective optimization problems through non-dominated sorting and congestion comparison, and is suitable for scenarios where multiple conflicting objectives need to be optimized simultaneously. MOVEA

[0070] In one embodiment, specifically, a≥80, b≥1.1, c≥150, and d≥1.8 are used to save computing resources and optimize computing time. Preferably, a=100, b=1.3, c=200, and d=2 are used to maximize computing resources and save computing time.

[0071] In one embodiment, the total matrix is represented as an N×3 matrix, where N is the number of brain grids, which is consistent with the N of the lead field matrix, and 3 is the x, y, and z directions. The step S600 extracts and constructs the target point matrix from the total matrix based on the two target point coordinates of S100, specifically including:

[0072] Calculate the second norm of the second dimension of the total matrix. Based on the two target point coordinates in S100, find a sphere with the target point as the center and a radius of r. Extract the corresponding portion of the sphere in the matrix to construct a new matrix, namely the target point matrix; 1.3 cm > r > 0.8 cm. r is preferably 1 cm.

[0073] Specifically, Python can be used to implement the method for determining the parameters of the dual-target temporal interferometric stimulation electrode described in the above embodiment. In terms of code implementation, the present invention first reads the lead field matrix and target coordinates required by the user, and then finds the corresponding grid number in the lead field matrix based on the target coordinates. For optimal results, a weighted calculation of the average electric field can be performed for a subset of cases.

[0074] The code is available in CPU and GPU versions. The GPU version uses the Pytorch architecture and requires the target computer to have an NVIDIA GPU for accelerated computing. The CPU version takes about 10 minutes to obtain the first feasible solution, and the full runtime is about 450 minutes. After obtaining the first feasible solution, you can choose to terminate the program. The specific calculation time will be greatly affected by the CPU model and the accuracy of the lead field matrix. The time given above was tested on an M2 Pro chip with a total grid size of approximately 7 million. The GPU version is more than 10 times faster than the CPU version. The code requires the computer to have at least 20GB of available memory and can run on Windows, Linux, and macOS systems.

[0075] This invention has been validated using computer electric field finite element simulations. The code runs ensure that when stimulating deep nuclei such as the thalamus, the ratio of the electric field intensity at the target location to the average electric field intensity in the brain is greater than 1.3. In actual results, with a limit of 150 iterations, the electric field ratio in the thalamus can reach a maximum of 2.05.

[0076] The main goal of the present invention is temporal interference stimulation of the brain, but the present invention can be directly applied to other biological tissues such as the spinal cord. In theory, the present invention can also be applied to any container or medium such as saline. The object of the present invention is only related to the lead field matrix input by the user. How to construct the lead field matrix is not included in the scope of the present invention.

[0077] In a more specific embodiment, the MNI 152-2009b image was used as the experimental target image, and a lead field matrix for the image was constructed using simnibs. The 10-10 international standard lead was used as the electrode channel. The MNI coordinates (33.3, -67.2, 5.7) and (-33.3, -67.2, 5.7) were input, along with electrode frequencies of 2000 Hz, 2010 Hz, 2020 Hz, and 2030 Hz. The method of the above embodiment was used to output several sets of results. For example, the first result was selected to obtain the currents for the first electrode pair [PO9 and P7, current 1.207 mA, frequency 2000 Hz], the second electrode pair [P5 and F3, current 0.703 mA, frequency 2010 Hz], the third electrode pair [PO8 and O2, current 0.977 mA, frequency 2020 Hz], and the fourth electrode pair [CP4 and CP5, current 1.203 mA, frequency 2030 Hz]. The electric field simulation is carried out based on the above results, and we get Figure 2 , where the closer the color distribution is to red, the higher the electric field is, and the closer it is to blue, the lower the electric field is. From the electric field simulation results, it can be seen that the electric field intensity at the MNI coordinates (33.3, -67.2, 5.7) is approximately 0.273V / m, the electric field intensity at the MNI coordinates (-33.3, -67.2, 5.7) is approximately 0.311V / m, and the average electric field intensity in the brain is approximately 0.063V / m. The electric field intensity thresholds of the target points all exceed the activation threshold of 0.25V / m, and the ratio to the average electric field intensity in the brain exceeds 4. The total current is within the safe range of 4mA, proving that the placement of the above four pairs of electrodes has a significant stimulation effect and focusing effect on the target points.

[0078] In one embodiment, a dual-target time interference stimulation method uses electrode parameters determined by the above-mentioned method for determining electrode parameters of dual-target time interference stimulation to achieve accurate and efficient dual-target stimulation effects.

[0079] In one embodiment, the electrode frequency is ≥500 Hz, Δf is ≤100 Hz, and the total current of all electrodes is ≤4 mA. Furthermore, f should not be less than 500 Hz, Δf should not be greater than 100 Hz, and the total current of four pairs of electrodes (eight pairs) should not exceed 4 mA. The preset electrode arrangement uses the 10-10 international standard lead system, and the total number of preset electrodes is 76 (preset electrodes refer to possible electrode placement locations).

[0080] In this specification, the use of terms such as "Embodiment 1," "this embodiment," and "in one embodiment" indicates that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in the invention or at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example; furthermore, the specific features, structures, materials, or characteristics described may be appropriately combined in any one or more embodiments or examples.

[0081] In the description of this specification, the terms "connect," "install," "fix," "dispose," and "have" are to be understood in a broad sense. For example, "connect" can mean a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0082] In the description of this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising the element.

[0083] The above description of the embodiments is to facilitate ordinary technicians in this technical field to understand and apply the technology of this case. People familiar with the technology in this field can obviously make various modifications to these examples easily and apply the general principles described here to other embodiments without having to go through creative work. Therefore, this case is not limited to the above embodiments. Modifications to the following situations should all be within the scope of protection of this case: ① A new technical solution implemented based on the technical solution of the present invention and combined with existing common knowledge, the technical effect produced by the new technical solution does not exceed the technical effect of the present invention; ② The equivalent replacement of some features of the technical solution of the present invention with the known technology, the technical effect produced is the same as the technical effect of the present invention; ③ The technical solution of the present invention is expandable, and the substantive content of the expanded technical solution does not exceed the technical solution of the present invention; ④ The equivalent transformation made by the content of the description and drawings of the present invention is directly or indirectly applied to other related technical fields.

Claims

1. A method for determining parameters of dual-target temporal interferometric stimulation electrodes, characterized in that: The method comprises: S100: Input the lead field matrix of the subject's head model, the coordinates of two target points, and the electrode frequency; S200, generating a random solutions to form a random solution matrix, wherein the structure of the solution matrix is the electrode position and the corresponding current magnitude; a>1; S300, multiplying the solution matrix by the lead field matrix to obtain a high-frequency electric field corresponding to each pair of electrodes; S400, the electrode frequency of S100 and the high-frequency electric field corresponding to each pair of electrodes of S300 are input into the Grossman formula to obtain the frequency and 2 sets of envelope electric fields of ΔfHz; Δf is the frequency increment between two adjacent pairs of electrodes; S500, performing Hilbert transform and space vector summation on the two sets of envelope electric fields obtained in S400 to form a total matrix; S600, extracting and constructing a target point matrix from the total matrix in S500 according to the two target point coordinates in S100; S700, calculating the ratio of the average electric field strength of the target matrix to the average electric field strength of the total matrix. If the ratio is less than b, the corresponding random solution is removed; if the ratio is greater than b, the corresponding random solution is retained and a new random solution is generated to form a new random solution; b>1; S800 and S300-S700 constitute one iteration, and the termination condition of the iteration is: The number of iterations reaches c, and / or The ratio in S700 is greater than d, d>b; If the termination condition is met, the random solution retained in S700 is output.

2. The determination method according to claim 1, characterized in that The S500 specifically includes: Substituting E1=cosπΔf and E2=cos 2πΔf into the Hilbert transform formula, the result is the fusion field equation of the two envelope fields E1 and E2 are two electric fields of dual-target temporal interference stimulation; the two sets of envelope electric fields obtained by S400 are vector-summed to obtain the electric field distribution in space; according to the fusion field equation And the electric field distribution in space is obtained to obtain the total matrix.

3. The determination method according to claim 1, characterized in that The S200 generates a random solutions using a multi-objective optimization algorithm.

4. The determination method according to claim 1, characterized in that The S700 generates a new random solution using a multi-objective optimization algorithm, wherein the optimization objectives of the multi-objective optimization algorithm are to maximize the average electric field intensity of the target matrix and minimize the average electric field intensity of the total matrix.

5. The determination method according to claim 3 or 4, characterized in that: The multi-objective optimization algorithm is one of genetic algorithm, NSGA-II, MOVEA or particle swarm optimization.

6. The determination method according to any one of claims 1 to 4, characterized in that: Said a≥80; b≥1.1; c≥150; d≥1.

8.

7. The determination method according to claim 1, characterized in that: The step S600 extracts and constructs a target point matrix from the total matrix based on the two target point coordinates of the step S100, specifically including: The second norm of the second dimension of the total matrix is calculated. According to the coordinates of the two target points in S100, a sphere with the target point as the center and a radius of r is found. The corresponding part of the sphere in the matrix is extracted to construct a new matrix, namely the target point matrix; 1.3 cm>r>0.8 cm.

8. A dual-target temporal interference stimulation method, characterized in that: Stimulation is performed using the electrode parameters determined by the method for determining dual-target time interference stimulation electrode parameters as described in any one of claims 1 to 7.

9. The stimulation method according to claim 8, characterized in that The electrode frequency is ≥500 Hz, Δf ≤100 Hz, and the total current of all electrodes is ≤4 mA.

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