EEG-based brain stimulation measurement and control circuit and integrated measurement and control machine

Abstract

The EEG-based electroencephalography (EEG) monitoring and control circuit and integrated monitoring and control device in this embodiment include: a multi-channel EEG pickup circuit, a multi-channel constant current source circuit, and a signal switching circuit; the multi-channel EEG pickup circuit and the multi-channel constant current source circuit are both connected to multiple electrode links operating in parallel through the signal switching circuit; the signal switching circuit achieves parallel connection with multiple electrode links through a built-in multi-channel analog switch matrix; when the input level received by the multi-channel analog switch matrix is ​​a first level, the electrode link is connected to the multi-channel EEG pickup circuit; when the input level received by the multi-channel analog switch matrix is ​​a second level, the electrode link is connected to the multi-channel constant current source circuit. This enables integrated operation and management of subject EEG data acquisition and EEG stimulation application, effectively improving work efficiency and is applicable to the field of medical and nursing technology.

Description

Technical Field

[0001] This application relates to the field of medical and nursing technology, specifically to EEG-based brain stimulation measurement and control circuits, integrated measurement and control machines, and measurement and control methods. Background Technology

[0002] Transcranial direct current stimulation (tDCS) is a neuromodulation technique that has attracted much attention in recent years in the fields of cerebrovascular diseases and mental illnesses. It consists of two surface electrodes, an anode and a cathode, and a controller. During use, the electrodes are placed on the surface of the brain, and the controller outputs a weakly polarized direct current to the cerebral cortex by setting the stimulation type. Unlike other non-invasive brain stimulation techniques, such as transcranial electrical stimulation (tES) and transcranial magnetic stimulation (TMS), tDCS does not induce neuronal firing through suprathreshold stimulation, but rather works by modulating the activity of neural networks in the cerebral cortex.

[0003] At the neuronal level, the basic mechanism by which tDCS regulates cortical excitability is based on changes in resting membrane potential caused by different stimulus polarities, leading to hyperpolarization or depolarization. The polarization of the tDCS membrane involves the influence of current on neuronal membrane potential and is the primary mechanism of the immediate effect of tDCS stimulation. This is mainly achieved through: anodic currents lower the membrane potential, making it easier for neurons to reach the action potential threshold, thereby enhancing neural activity; cathodic currents increase the membrane potential, making it more difficult for neurons to reach the action potential threshold, thereby inhibiting neural activity. Therefore, anodic stimulation typically depolarizes neurons, increasing excitability, while cathodic stimulation hyperpolarizes neurons, reducing excitability.

[0004] Traditional electroencephalography (EEG) and traditional non-invasive brain stimulation techniques (such as tES) are usually used separately. EEG machines only extract, acquire, transmit, and analyze EEG signals, and use configured electrode caps (such as wet electrodes and saline electrodes) to examine various clinical EEG signals and record brain electrical activity. tES, on the other hand, uses different sized stimulation electrodes to apply direct current or alternating current stimulation to the skin according to a prescription to regulate brain activity. The two types of devices cannot work simultaneously, and the signals cannot be fused.

[0005] In scientific research and clinical practice, there is an increasing demand for interventions that combine EEG monitoring with non-invasive brain stimulation techniques. This combination allows for real-time monitoring of the brain's response and adjustment of stimulation parameters based on feedback, thereby improving the accuracy and effectiveness of treatments or experiments.

[0006] However, existing technologies often lack integrated devices that can manage both technologies simultaneously. Furthermore, existing tDCS devices are single-channel stimulators, failing to achieve multi-source radiation stimulation and multi-point convergence stimulation, making it difficult to simulate neural network communication. They also fail to achieve simultaneous recording of EEG and TRIG, resulting in complex operation and low efficiency. Summary of the Invention

[0007] To address one of the aforementioned technical deficiencies, this application provides an EEG-based brain stimulation measurement and control circuit, an integrated measurement and control machine, and a measurement and control method, which can realize integrated operation and management of subject EEG data acquisition and brain stimulation application, and can effectively improve work efficiency.

[0008] The first aspect of the embodiments of this application provides an EEG-based brain stimulation measurement and control circuit, including: a multi-channel EEG pickup circuit, a multi-channel constant current source circuit, and a signal switching circuit;

[0009] The multi-channel EEG pickup circuit and the multi-channel constant current source circuit are both connected to multiple electrode links that operate in parallel through a signal switching circuit;

[0010] The signal switching circuit achieves parallel connection with multiple electrode links through a built-in multi-channel analog switch matrix;

[0011] When the input level received by the multi-channel analog switch matrix is ​​the first level, the electrode link is connected to the multi-channel EEG pickup circuit.

[0012] When the input level received by the multi-channel analog switch matrix is ​​the second level, the electrode link is connected to the multi-channel constant current source circuit.

[0013] In an optional embodiment of this application, each of the electrode links is capable of outputting or receiving current. When the sum of the input and output currents of the multiple electrode links is zero, the multiple electrode links are capable of performing homologous star-shaped radiation stimulation and multi-source multipath homologous stimulation on the skin.

[0014] In an optional embodiment of this application, the multi-channel constant current source circuit includes: a multi-channel constant current source generator and a first control unit;

[0015] The multi-channel constant current source generator includes: multiple voltage-controlled source circuits; each voltage-controlled source circuit is connected to multiple voltage-controlled constant current source circuits that operate in parallel.

[0016] The output terminals of the multiple voltage-controlled constant current source circuits are connected to the multiple electrode links one-to-one through a multi-channel analog switch matrix;

[0017] The voltage-controlled power source circuit outputs DC, AC, random, or arbitrary waveform data according to the parameter settings of the first control unit, thereby driving the voltage-controlled constant current source circuit to operate.

[0018] In an optional embodiment of this application, the multi-channel constant current source circuit further includes: a multi-channel current and contact impedance detection circuit;

[0019] The multi-channel current and contact impedance detection circuit includes: multiple current detection circuits;

[0020] The number of current detection circuits is the same as the number of voltage-controlled constant current source circuits, and each current detection circuit is respectively set on the output link of the voltage-controlled constant current source circuit.

[0021] When the current value obtained by the current detection circuit on the corresponding voltage-controlled constant current source circuit exceeds the preset value, the electrode link connected to the corresponding voltage-controlled constant current source circuit is turned off.

[0022] In an optional embodiment of this application, the current detection circuit is provided with an impedance detection unit; the impedance detection unit detects the contact impedance value between the electrode and the skin, and when the contact impedance value is less than a preset value, it indicates that the electrode has fallen off.

[0023] In an optional embodiment of this application, the multi-channel EEG pickup circuit includes: a second control unit, which is connected to multiple EEG signal acquisition circuits in parallel.

[0024] The input terminals of the multiple EEG signal acquisition circuits are connected to the multiple electrode links one-to-one through a multi-channel analog switch matrix;

[0025] After receiving the start / stop signal from the second control unit, the EEG signal acquisition circuit turns on or off the connection with the electrode link.

[0026] In an optional embodiment of this application, the first level is a low level in the PWM level signal, and the second level is a high level in the PWM level signal.

[0027] A second aspect of this application provides an EEG-based brain stimulation measurement and control integrated machine, comprising: a human-computer interaction device and a brain stimulation measurement and control circuit; the human-computer interaction device and the brain stimulation measurement and control circuit are communicatively connected.

[0028] The brain stimulation measurement and control circuit is the EEG-based brain stimulation measurement and control circuit described above.

[0029] In an optional embodiment of this application, an isolation circuit is provided between the human-computer interaction device and the brain stimulation measurement and control circuit.

[0030] In an optional embodiment of this application, the human-computer interaction device includes: a main controller and a data transmission circuit; the main controller is connected to a peripheral device through the data transmission circuit.

[0031] A third aspect of the embodiments of this application provides a brain stimulation measurement and control method based on EEG, including the brain stimulation measurement and control circuit based on EEG as described above.

[0032] The method includes the following steps:

[0033] Obtain the pre-stimulation EEG acquisition parameters, stimulation parameters, and post-stimulation EEG acquisition parameters corresponding to the treatment plan;

[0034] Based on the pre-stimulation EEG acquisition task parameters, stimulation task parameters, and post-stimulation EEG acquisition task parameters, an input level sequence for a multi-channel analog switch matrix is ​​generated.

[0035] The signal switching circuit automatically switches the conduction of the multi-channel EEG pickup circuit and the multi-channel constant current source circuit with the electrode link according to the input level sequence through the built-in multi-channel analog switch matrix, so as to complete the EEG signal acquisition and brain stimulation output.

[0036] Compared with the prior art, the technical solutions provided in the embodiments of this application are as follows:

[0037] 1. In the embodiments of this application, the electrode link is connected to the multi-channel EEG pickup circuit or the electrode link is connected to the multi-channel constant current source circuit through the signal switching circuit. This enables the on-demand switching between the stimulation function and the EEG pickup function, allowing stimulation to be performed simultaneously during the EEG signal pickup process. This not only reduces signal interference and data inaccuracy caused by the alternating operation of the two functions, thus improving work efficiency, but also allows the operator to monitor the brain's response in real time and adjust the stimulation parameters according to the feedback parameters of the EEG pickup function, thereby improving the accuracy of treatment or experimentation.

[0038] 2. In the embodiments of this application, each electrode link can output or receive current. When the sum of the input and output currents of multiple electrode links is zero, multiple electrode links can perform homologous star-shaped radiation stimulation and multi-source multipath homologous stimulation on the skin. By simulating the communication mode between neural networks, networked mutual stimulation of the left and right halves is achieved.

[0039] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of what is pointed out in the written description and the accompanying drawings. Attached Figure Description

[0040] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0041] Figure 1 A schematic diagram of the structure of an EEG-based brain stimulation measurement and control circuit provided in one embodiment of this application;

[0042] Figure 2 A circuit schematic diagram of a channel analog switch matrix provided in one embodiment of this application;

[0043] Figure 3 A schematic diagram of a multi-channel constant current source circuit structure in an EEG-based electroencephalography (EEG) monitoring and control circuit provided in one embodiment of this application;

[0044] Figure 4 This is a schematic diagram of the circuit principle of a multi-channel constant current source generator in one embodiment of this application;

[0045] Figure 5 This is a circuit diagram of a current detection circuit in one embodiment of this application;

[0046] Figure 6 This is a circuit schematic diagram of electrode contact DC impedance detection in one embodiment of this application;

[0047] Figure 7 This is a circuit schematic diagram of the electrode contact AC impedance detection in one embodiment of this application;

[0048] Figure 8 A schematic diagram of the structure of a multi-channel EEG pickup circuit in an EEG-based electroencephalography (EEG) monitoring and control circuit provided in one embodiment of this application;

[0049] Figure 9 This is a circuit diagram of the second control unit and the electroencephalogram (EEG) signal acquisition circuit in one embodiment of this application;

[0050] Figure 10 This is a schematic diagram of the network structure of an EEG-based brain stimulation measurement and control integrated machine in one embodiment of this application;

[0051] In the picture:

[0052] 10 is the brain stimulation measurement and control circuit, 20 is the human-computer interaction device, and 30 is the isolation circuit;

[0053] 101 is a multi-channel EEG pickup circuit, 102 is a multi-channel constant current source circuit, 103 is a signal switching circuit, and 104 is an electrode link.

[0054] 1011 is the second control unit, and 1012 is the electroencephalogram (EEG) signal acquisition circuit;

[0055] 1021 is the first control unit; 1022 is a multi-channel constant current source generator; 1023 is a multi-channel current and contact impedance detection circuit.

[0056] 10221 is a voltage-controlled power source circuit, and 10222 is a voltage-controlled constant current source circuit;

[0057] 301 is a high-speed magnetic isolation circuit, and 302 is an isolated power supply. Detailed Implementation

[0058] In order to ensure the accuracy of the citations and the fluency of reading, the key technical terms, abbreviations or acronyms used in the text are summarized and explained as follows:

[0059] EEG, electroencephalogram;

[0060] tES, Transcranial Electrical Stimulation;

[0061] tDCS, Transcranial Direct Current Stimulation;

[0062] tACS, Transcranial Alternating Current Stimulation;

[0063] tRNS, Transcranial random noise stimulation;

[0064] TMS, Transcranial Magnetic Stimulation;

[0065] Sham, a false stimulus;

[0066] ADC, Analog-to-digital converter;

[0067] RS232, Electronic Industries Association (EIA) Standard-RS-232, is the RS-232 communication interface standard developed by the Electronic Industries Association.

[0068] In the process of realizing this application, the inventors discovered that electroencephalography (EEG), as a commonly used neurological function detection technology, can record the electrical activity of neurons and can non-invasively record the instantaneous brain activity of the entire brain surface, with the advantage of high temporal resolution. In use, the electrodes on the EEG electrode cap are in close contact with the scalp through conductive gel or saline solution to sense the EEG signal, which is then transmitted through wires to the EEG machine for amplification, filtering, digitization and other processing, and finally converted into an EEG waveform that can be analyzed and diagnosed by doctors.

[0069] In the current field, traditional brain stimulation devices mostly use fixed stimulation methods and parameters in the detection and treatment of mental illnesses in subjects. They apply direct current or alternating current stimulation to the skin to regulate brain activity. For brain activity before and after diagnosis and treatment, an electroencephalogram (EEG) machine can be used for recording and analysis, which is inconvenient and cumbersome to operate.

[0070] To address the aforementioned issues, this application provides an EEG-based brain stimulation measurement and control circuit.

[0071] To make the technical solutions and advantages of the embodiments of this application clearer, the exemplary embodiments of this application will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0072] like Figure 1 As shown, exemplarily, the EEG-based brain stimulation control circuit includes: a multi-channel EEG pickup circuit 101, a multi-channel constant current source circuit 102, and a signal switching circuit 103;

[0073] The multi-channel EEG pickup circuit 101 and the multi-channel constant current source circuit 102 are both connected to multiple electrode links 104 that operate in parallel through the signal switching circuit 103.

[0074] The signal switching circuit 103 achieves parallel connection with multiple electrode links 104 through a built-in multi-channel analog switch matrix;

[0075] When the input level received by the multi-channel analog switch matrix is ​​the first level, the electrode link 104 is connected to the multi-channel EEG pickup circuit 101.

[0076] When the input level received by the multi-channel analog switch matrix is ​​the second level, the electrode link 104 is connected to the multi-channel constant current source circuit 102.

[0077] Based on the above scheme, this application enables the electrode link 104 to be connected to the multi-channel EEG pickup circuit 101 or the electrode link 104 to be connected to the multi-channel constant current source circuit 102 through the signal switching circuit 103. This allows for on-demand switching between the stimulation function and the EEG pickup function, enabling simultaneous stimulation (including multi-source stimulation and homologous radiation stimulation) during the EEG signal pickup process. This not only reduces signal interference and data inaccuracy caused by the alternating operation of the two functions, thus improving work efficiency, but also allows the operator to monitor the brain's response in real time and adjust the stimulation parameters according to the feedback parameters of the EEG pickup function, thereby improving the accuracy of treatment or experimentation.

[0078] In this embodiment, the input level value received by the multi-channel analog switch matrix can be set according to the specific application scenario and equipment deployment. For example, it can come from the control module of the multi-channel EEG pickup circuit 101 and / or the multi-channel constant current source circuit 102; or it can come from an external control device, such as the human-computer interaction device described in another embodiment of this application.

[0079] In one optional embodiment of this application, each of the electrode links 104 is capable of outputting or receiving current. When the sum of the input and output currents of the multiple electrode links 104 is zero, the multiple electrode links 104 can perform homologous star-shaped radiation stimulation and multi-source multipath homologous stimulation on the skin. By simulating the communication mode between neural networks, networked mutual stimulation of the left and right halves can be achieved.

[0080] Specifically, when the electrode links 104 are used in pairs, with one electrode value being positive and the other negative, and the sum of the input and output currents of each pair of electrode links 104 being zero, then multiple electrode links 104 can provide homologous star-shaped radiation stimulation to the skin.

[0081] When the electrode links 104 are used in groups of multiple electrodes, one electrode link 104 in each group of electrode links 104 is the negative electrode, and the other several electrode links 104 are the sub-positive electrodes, and the sum of the input and output currents of the multiple sub-positive electrodes and the negative electrodes is zero; then, the multiple electrode links 104 can perform multi-source and multi-path homologous stimulation on the skin.

[0082] like Figure 2 As shown, in an optional embodiment of this application, the multi-channel analog switch matrix of the signal switching circuit 103 can be composed of multiple analog switches of model ADG1434 connected in series, and can be selected through the IO expansion port controlled by the I2C bus.

[0083] Because EEG signals have poor signal-to-noise ratio, low amplitude, and are generally in the μV range, while the stimulation current is at most 4mA, and the amplitude can reach as high as 16V if the stimulation impedance is 4K, the signal difference between the EEG signal and the stimulation current is more than 160,000 times (100dB). Therefore, this application uses an analog switch with low on-resistance and high inter-channel crosstalk isolation to isolate the EEG signal and the stimulation current and prevent signal interference.

[0084] Specifically, the first level can be a low level in the PWM level signal, and the second level can be a high level in the PWM level signal; when the input of a certain analog switch in the multi-channel analog switch matrix is ​​low, the system switches to the EEG channel, and when the input of the analog switch is high, the system switches to the stimulation channel.

[0085] The electrode link 104 in this embodiment can be used simultaneously in scenarios involving stimulation and EEG acquisition. Before use, the pre-stimulation EEG acquisition task, stimulation task, and post-stimulation EEG acquisition task can be set according to the treatment plan. During use, the stimulation function or EEG acquisition function is automatically switched according to the corresponding task. Compared with the traditional method, the electrode insertion and removal between the two functions is reduced, the operation process is simplified, and interference from EEG fluctuations caused during insertion and removal is avoided.

[0086] In this embodiment of the application, in the scenario of applying the EEG pickup function, the total number of channels of the multi-channel EEG pickup circuit 101 can be 40; in the scenario of applying the stimulation function, the total number of channels of the multi-channel constant current source circuit 102 can be 20.

[0087] like Figure 3 As shown, the multi-channel constant current source circuit 102 includes: a multi-channel constant current source generator 1022 and a first control unit 1021;

[0088] The multi-channel constant current source generator 1022 includes: multiple voltage-controlled source circuits 10221; each voltage-controlled source circuit 10221 is connected to multiple voltage-controlled constant current source circuits 10222 that operate in parallel.

[0089] The output terminals of the multiple voltage-controlled constant current source circuits 10222 are connected to the multiple electrode links 104 one by one through a multi-channel analog switch matrix;

[0090] The voltage-controlled source circuit 10221 outputs DC, AC, random, or arbitrary waveform data according to the parameter settings of the first control unit 1021, thereby driving the voltage-controlled constant current source circuit 10222 to operate.

[0091] In this embodiment, the stimulation mode of the stimulation channel formed by the multi-channel constant current source circuit 102 and the electrode link 1021 can be divided into four types:

[0092] DC stimulation (achieved by tDCS, with adjustable intensity);

[0093] Pulse stimulation (achieved by tACS, with adjustable intensity, frequency, and phase);

[0094] White noise stimulation (achieved by tRNS, with intensity modulated);

[0095] False stimulation (in this mode, the stimulation time can be adjusted).

[0096] Specifically, each of the electrode links 104 is capable of outputting or receiving current; when used as a stimulation channel, each channel (here referring to an electrode link 104) can apply only one stimulation mode or apply three stimulation modes simultaneously, and can be used in conjunction with sham stimulation.

[0097] However, the total intensity of the three stimulation methods (tDCS, tACS, tRNS) cannot exceed 2000 uA.

[0098] When used as a stimulation channel, it is essential to ensure that the intensities cancel each other out, i.e., the sum is 0.

[0099] In this embodiment, the voltage-controlled source circuit (10221) can be composed of three 16-bit digital-to-analog converters AD5668ARUZ-2 to output DC, AC, random, and arbitrary waveform data, driving the voltage-controlled constant current source circuit (10222). Since each AD5668ARUZ-2 has 8 channels, each AD5668ARUZ-2 can connect to a maximum of 8 voltage-controlled constant current source circuits (10222).

[0100] The voltage-controlled constant current source circuit (10222) can be composed of 20 dual instrumentation amplifiers AD8426 and 5 quad operational amplifiers AD8624; the dual instrumentation amplifiers and quad operational amplifiers constitute a 2mA level voltage-controlled constant current source circuit.

[0101] In this embodiment, the digital-to-analog converter AD5668ARUZ-2 outputs a stimulation waveform signal of 0–2.5V, which is input to the positive terminal of the instrumentation amplifier AD8426, raising the negative terminal of the instrumentation amplifier AD8426 to a level of 1.25V, thus changing the range to ±1.25V. The sampling resistor can be set to 500 ohms. Therefore:

[0102] Constant current range: ±1.25V / 500Ω=±2.5mA, i.e. -2.5mA~2.5mA;

[0103] The current resolution is: 5mA / 65535 = 76nA.

[0104] In the hardware implementation of the multi-channel constant current source circuit 102: one quad operational amplifier AD8624 and four dual instrumentation amplifiers AD8426 constitute one group of four-channel voltage-controlled constant current source circuits; therefore, five quad operational amplifiers AD8624 and twenty dual instrumentation amplifiers AD8426 together constitute five groups of four-channel voltage-controlled constant current source circuits, and the outputs of the twenty dual instrumentation amplifiers correspond to the twenty outputs of the voltage-controlled constant current source circuits.

[0105] The connection between the voltage-controlled source circuit (10221) and the voltage-controlled constant current source circuit (10222) can be as follows:

[0106] The first digital-to-analog converter, AD5668ARUZ-2, is connected to two sets of four-channel voltage-controlled constant current source circuits;

[0107] The second digital-to-analog converter, AD5668ARUZ-2, is connected to two sets of four-channel voltage-controlled constant current source circuits;

[0108] The third digital-to-analog converter, AD5668ARUZ-2, is connected to a group of four voltage-controlled constant current source circuits.

[0109] As an example, the circuit diagram of the first digital-to-analog converter AD5668ARUZ-2 connected to two groups of four-channel voltage-controlled constant current source circuits is as follows: Figure 4 As shown.

[0110] In this embodiment of the application, the multi-channel constant current source circuit 102 further includes: a multi-channel current and contact impedance detection circuit 1023;

[0111] The multi-channel current and contact impedance detection circuit 1023 includes: multiple current detection circuits;

[0112] The number of current detection circuits is the same as the number of voltage-controlled constant current source circuits 10222, and each current detection circuit is respectively set on the output link of the voltage-controlled constant current source circuit 10222.

[0113] When the current value obtained by the current detection circuit on the corresponding voltage-controlled constant current source circuit 10222 exceeds the preset value, the electrode link 104 connected to the corresponding voltage-controlled constant current source circuit 10222 is turned off.

[0114] In this embodiment of the application, in order to ensure the safe current output of transcranial stimulation, a current detection chip is placed at the output position of the voltage-controlled constant current source circuit 10222. The current detection chip can detect the voltage drop across the current sensing resistor in a common-mode voltage range of -0.2V to +26V, independent of the power supply voltage.

[0115] The current sensing chip may be model AD8426. The current sensing chip integrates a matched resistor gain network with four fixed gain device options. This integrated matched resistor gain network can minimize gain error and reduce temperature drift. In this embodiment, the current sensing chip model AD8426 is powered by a power supply from -15V to +15V and consumes a maximum power supply current of 260μA.

[0116] Specifically, in the circuit implementation, the sensing resistor Rsense can be connected in series to the output of the voltage-controlled constant current source circuit 10222, and the output of the current sensing chip AD8426 can be connected to the controller through the ADC module. When a ±5mA current passes through the sensing resistor Rsense (10 ohms), a ±50mV voltage is generated. Since the amplification factor of the current sensing chip AD8426 is 25 times, the output voltage of the current sensing chip AD8426 is ±1.25V. The ADC resolution is 16 bits, and the resolution is 2.5V / 65535=0.04mV. The current measurement accuracy reaches 0.15uA, which can meet the requirements of output current amplitude detection.

[0117] To improve detection accuracy, the detection resistor Rsense can be a resistor with 0.1% accuracy and a temperature coefficient of 25ppm / ℃.

[0118] During real-time monitoring, if the controller detects that the output current exceeds 5mA, it will immediately shut off the stimulation current and flash an indicator light to warn the subject. When the detection resistor Rsense is short-circuited, open-circuited, or the current detection chip is faulty, the voltage detected by the controller will be within a fixed range. If the stimulation mode is in pulse mode (tACS), the detection circuit can be identified as faulty.

[0119] The controller may be the first control unit in this embodiment of the application, or it may be a human-computer interaction device.

[0120] In this embodiment of the application, the circuit diagram of the current detection circuit is as follows: Figure 5 As shown, Figure 5 In this circuit, IL is the output of the previous constant current source circuit, and J is connected to the electrode link.

[0121] In this embodiment of the application, an impedance detection unit is provided on the current detection circuit;

[0122] The impedance detection unit detects the contact impedance value between the electrode and the skin. When the contact impedance value is less than a preset value, it indicates that the electrode has detached.

[0123] In this embodiment, the impedance detection unit may include: electrode contact DC impedance detection and electrode contact AC impedance detection.

[0124] like Figure 6 As shown, in the circuit for detecting DC impedance of electrode contact: when the gain resistor Rg is not used, the current detection chip (model: AD8426) is set by default to: current amplification factor G = 1;

[0125] Constant current = (V_DA - 1.25V) / R_sample 1;

[0126] I = 1.25 / 560 = ±2.232mA;

[0127] I_S_OUT=10Ω*I*50+1.25V=1.25V±1.116V=0.134V~2.336V

[0128] V_OUT=(V_STIM+22*1.25V) / 23;

[0129] Where 22 = 220K / 10K; 23 = (220K+10K) / 10K, and 560 is the resistance value of the sampling resistor.

[0130] like Figure 7 As shown, the detection principle of the impedance detection unit is as follows:

[0131] Establish a resistance model Rx for lead CH (electrode link) relative to reference Ref, an impedance model Rch relative to ground, and an impedance model Rref for reference Ref relative to ground; where lead CH is any lead; the final measured voltage signal is the voltage difference relative to reference Ref. Therefore, Rx reflects the impedance characteristics between the lead and the reference.

[0132] A stimulation current of 200 nA is injected into all electrodes in the head, including the reference electrode; therefore, the actual injected current is 200 nA. All lead currents return to signal ground through the ground electrode. Relative to the reference electrode, the current injected into lead CH is divided into Ix and Ich, i.e., Ich0 = Ix + Ich. The internal impedance of the head is discrete and its distribution is complex, making the measurement of Rx quite complex. Considering that the voltage generated by the reference current is a common-mode signal, we simplify the schematic by assuming Rref is 0 and Rch is Rx, resulting in:

[0133]

[0134] U xd For U x -U ref Rh = 100 MΩ, Ug = 4.5 V;

[0135]

[0136] Due to U g <<Uxd ,

[0137] Calculation method:

[0138] After data collection, calculate U x -U ref =U xd , get U xd The waveform, which contains DC and signals outside 30Hz in the acquired signal, is passed through a 28-32Hz digital bandpass filter (9th order IIR Butterworth) to calculate U. xd The mean square value of the signal within 1 second, substituted into U xd / 200nA, calculated.

[0139] like Figure 8 As shown in the embodiment of this application, the multi-channel EEG pickup circuit 101 includes: a second control unit 1011, which is connected to multiple EEG signal acquisition circuits 1012 in parallel.

[0140] The input terminals of the multiple EEG signal acquisition circuits 1012 are connected to the multiple electrode links 104 one by one through a multi-channel analog switch matrix; after receiving the acquisition start and stop signal from the second control unit, the EEG signal acquisition circuit 1012 turns on or off the EEG electrode link 1011.

[0141] like Figure 9 As shown in the embodiment of this application, the EEG signal acquisition circuit 1012 may include: five 8-channel ADS1299 chips; the ADS1299 chips have eight independent 24-bit high-resolution analog-to-digital converters; the second control unit 1011 simultaneously configures the acquisition channels, sampling rate, amplification factor, and other parameters of the five ADS1299 chips through the SCLK and MOSI ports; the second control unit 101 drives the five ADS1299 chips to acquire signals simultaneously by activating the START signal.

[0142] In this embodiment, electroencephalography (EEG) has the advantages of being safe, non-invasive, inexpensive, and portable. Furthermore, the high temporal resolution of EEG enables it to capture the rapid dynamics of brain activity, making it unlike other brain monitoring methods (such as fMRI) which are slow to react. This allows for the rapid assessment of the effects of different stimuli. Therefore, recording EEG is crucial for the development of brain stimulation during transcranial stimulation.

[0143] One embodiment of this application also provides an EEG-based brain stimulation measurement and control integrated machine.

[0144] like Figure 10As shown, exemplarily, the EEG-based brain stimulation measurement and control integrated machine includes: a human-computer interaction device 20 and a brain stimulation measurement and control circuit 10;

[0145] The human-computer interaction device 20 and the brain stimulation measurement and control circuit 10 are communicatively connected;

[0146] The brain stimulation measurement and control circuit 10 is the EEG-based brain stimulation measurement and control circuit described above.

[0147] In this embodiment, a graphical interface can be used through the human-computer interaction device 20 to facilitate users in setting stimulation parameters and starting / stopping stimulation; it can also display the current stimulation parameters and device status, such as current intensity, stimulation time, electrode connection status, etc.; and it can also record data during the stimulation process for subsequent analysis and evaluation of treatment effects.

[0148] In this embodiment of the application, an isolation circuit 30 is provided between the human-computer interaction device 20 and the brain stimulation measurement and control circuit 10.

[0149] Specifically, the isolation circuit 30 includes a high-speed magnetic isolation circuit 301 and an isolation power supply 302; the high-speed magnetic isolation circuit 301 can use a magnetic field to isolate the human-computer interaction device 20 and the brain stimulation measurement and control circuit 10 to achieve the effects of isolation, protection and noise reduction.

[0150] In this embodiment of the application, the human-computer interaction device 20 includes: a main controller 201 and a data transmission circuit 202; the main controller 201 is connected to peripheral devices through the data transmission circuit.

[0151] For specific limitations regarding the aforementioned brain stimulation control circuit, please refer to the limitations mentioned above, which will not be repeated here.

[0152] The modules in the aforementioned EEG-based brain stimulation measurement and control circuit and the EEG-based integrated brain stimulation measurement and control machine can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of a computer device in hardware form or independent of it, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0153] One embodiment of this application also provides a brain stimulation measurement and control method based on EEG.

[0154] In this embodiment of the application, the stimulation task parameters include: stimulation intensity, frequency, waveform, and stimulation time.

[0155] Generally, the testing and treatment of subjects may include the following stages:

[0156] First, the preparation stage:

[0157] First, perform an equipment inspection to check whether all components involved in the method are properly connected, including electrode wires, stimulation output wires, etc., to ensure that there is no looseness or damage.

[0158] Secondly, turn on the power to the device and check whether the device can start normally and whether each functional module passes the self-test.

[0159] Next, prepare the electrodes. Select appropriate EEG electrode caps and stimulation electrodes as needed, and prepare conductive paste and conductive medium.

[0160] Afterwards, the subject is prepared. The procedure and precautions are explained to the subject to alleviate their anxiety and gain their cooperation. The subject is asked to wash their hair and keep their scalp clean and dry to reduce scalp resistance and improve the quality of EEG signal acquisition. The subject is then helped to sit or lie comfortably on the examination bed and adjust their position.

[0161] Second, the operational phase:

[0162] First, place the electrodes by correctly wearing the EEG electrode cap on the subject's head, ensuring close contact between the electrodes and the scalp; apply an appropriate amount of conductive gel between the electrodes and the scalp to reduce contact resistance and ensure a secure electrode connection.

[0163] Secondly, parameter settings are performed based on the specific condition of the subject and the corresponding treatment plan for the purpose of the examination: EEG acquisition task parameters are set, such as sampling frequency, filtering range, gain, etc.; at the same time, according to the stimulation task parameters, transcranial electrical stimulation parameters are set, including stimulation intensity, frequency, waveform, stimulation time, etc.

[0164] Next, after confirming that the parameter settings are correct, start collecting EEG signals; and check the signal quality through the real-time displayed EEG waveforms to ensure that there is no obvious interference or artifacts.

[0165] (If necessary, the electrode positions can be adjusted or the conductive medium can be reapplied to optimize signal acquisition. During the acquisition process, the subject should be asked to remain quiet and relaxed, avoiding large movements or behaviors that may cause interference, such as blinking or clenching their teeth.)

[0166] After the EEG signal is stabilized, transcranial electrical stimulation is applied to the subject's brain according to the set protocol. During the stimulation process, the subject's response is closely observed, and the subject is asked if there are any discomfort symptoms, such as headache, dizziness, scalp tingling, or other obvious discomfort. If so, the stimulation should be stopped immediately and the stimulation parameters should be adjusted.

[0167] During the above process, data recording and monitoring are performed, automatically recording EEG signals and tDCS stimulation current and voltage data, including: EEG waveform, stimulation current, stimulation waveform, stimulation voltage real-time parameters, etc., so that operators can view and analyze the data in real time and observe the changes in EEG signals before and after tDCS stimulation.

[0168] The EEG-based brain stimulation measurement and control method provided in this application, when applied at this stage, can improve the work efficiency of operators.

[0169] Third, the closing stage.

[0170] First, after completing the EEG acquisition and stimulation tasks as planned in the treatment plan, stop the stimulation output and then stop the acquisition of EEG signals.

[0171] Next, carefully remove the electrode caps from the subject's head, wipe away any residual conductive paste or other substances from the subject's scalp with clean water or a special cleaning agent to keep the scalp clean, and clean and disinfect the electrodes for future use.

[0172] Next, save the collected data to a computer or other storage device, and perform necessary organization and backup. If needed, further analysis and processing can be performed on the data, such as filtering, noise reduction, and feature extraction.

[0173] The scheme provided in this application enables simultaneous multi-source stimulation and homologous radial stimulation during EEG signal extraction, allowing for rapid study of EEG changes before and after stimulation, as well as the time effect after stimulation. This provides a real-time, accurate, and synchronous tool for brain science research and can be widely applied in fields such as medical health management and medical research.

[0174] For example, the technical solution provided in this application can collect the brain's response signals to electrical stimulation in real time, which makes it easier for operators to have a more comprehensive understanding of the brain's electrophysiological state, improve the accuracy of diagnosis, and provide a more accurate basis for subsequent surgical treatment.

[0175] For example, the technical solution provided in this application allows for the adjustment of stimulation parameters, such as intensity and frequency, based on the subject's electroencephalogram (EEG) activity data, thereby achieving personalized neuromodulation therapy, improving treatment efficacy, and reducing side effects.

[0176] For example, the technical solution provided in this application allows operators to continuously monitor changes in electroencephalogram (EEG) signals, facilitating the evaluation of tES treatment effects and timely adjustment of treatment plans.

[0177] For example, by using the technical solution provided in this application to record the changes in electrical activity of the brain region and related brain networks using EEG, researchers can gain a deeper understanding of the neural mechanisms of the brain and the neural information transmission and processing mechanisms in the brain during perception, memory, and learning. Furthermore, by applying different modes of tES stimulation and observing the changes in brain neural activity reflected by EEG signals, researchers can understand how the connections and functions between neurons in the brain change after stimulation, providing theoretical support for neurorehabilitation and treatment.

[0178] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A brain stimulation measurement and control circuit based on EEG, characterized in that, include: Multi-channel EEG pickup circuit (101), multi-channel constant current source circuit (102), and signal switching circuit (103); The multi-channel EEG pickup circuit (101) and the multi-channel constant current source circuit (102) are both connected to multiple electrode links (104) that operate in parallel through a signal switching circuit (103); The signal switching circuit (103) is connected in parallel with multiple electrode links (104) through a built-in multi-channel analog switch matrix; When the input level received by the multi-channel analog switch matrix is ​​the first level, the electrode link (104) is connected to the multi-channel EEG pickup circuit (101); When the input level received by the multi-channel analog switch matrix is ​​the second level, the electrode link (104) is connected to the multi-channel constant current source circuit (102).

2. The EEG-based brain stimulation measurement and control circuit according to claim 1, characterized in that, Each of the electrode links (104) can output or receive current. When the sum of the input and output currents of the multiple electrode links (104) is zero, the multiple electrode links (104) can perform homologous star-shaped radiation stimulation and multi-source multipath homologous stimulation on the skin.

3. The EEG-based brain stimulation measurement and control circuit according to claim 1, characterized in that, The multi-channel constant current source circuit (102) includes: a multi-channel constant current source generator (1022) and a first control unit (1021); The multi-channel constant current source generator (1022) includes: multiple voltage-controlled source circuits (10221); each voltage-controlled source circuit (10221) is connected to multiple voltage-controlled constant current source circuits (10222) operating in parallel; The output terminals of the multiple voltage-controlled constant current source circuits (10222) are connected to the multiple electrode links (104) one by one through a multi-channel analog switch matrix; The voltage-controlled source circuit (10221) outputs DC, AC, random or arbitrary waveform data according to the parameter settings of the first control unit (1021), driving the voltage-controlled constant current source circuit (10222) to run.

4. The EEG-based brain stimulation measurement and control circuit according to claim 3, characterized in that, The multi-channel constant current source circuit (102) further includes: a multi-channel current and contact impedance detection circuit (1023); The multi-channel current and contact impedance detection circuit (1023) includes: multiple current detection circuits; The number of current detection circuits is the same as the number of voltage-controlled constant current source circuits (10222), and each current detection circuit is respectively set on the output link of the voltage-controlled constant current source circuit (10222); When the current value obtained by the current detection circuit on the corresponding voltage-controlled constant current source circuit (10222) exceeds the preset value, the electrode link (104) connected to the corresponding voltage-controlled constant current source circuit (10222) is turned off.

5. The EEG-based brain stimulation measurement and control circuit according to claim 4, characterized in that, An impedance detection unit is provided on the current detection circuit; The impedance detection unit detects the contact impedance value between the electrode and the skin. When the contact impedance value is less than a preset value, it indicates that the electrode has detached.

6. The EEG-based brain stimulation measurement and control circuit according to claim 1, characterized in that, The multi-channel EEG pickup circuit (101) includes: a second control unit (1011), which is connected to multiple EEG signal acquisition circuits (1012) in parallel. The input terminals of the multiple EEG signal acquisition circuits (1012) are connected to the multiple electrode links (104) one by one through a multi-channel analog switch matrix; After receiving the start / stop signal from the second control unit, the EEG signal acquisition circuit (1012) turns on or off the connection with the electrode link (104).

7. The EEG-based brain stimulation measurement and control circuit according to claim 1, characterized in that, The first level is a low level in the PWM level signal, and the second level is a high level in the PWM level signal.

8. An integrated EEG-based brain stimulation measurement and control device, characterized in that, include: Human-computer interaction device (20) and brain stimulation measurement and control circuit (10); The human-computer interaction device (20) and the brain stimulation measurement and control circuit (10) are communicatively connected; The brain stimulation control circuit (10) is the brain stimulation control circuit based on EEG as described in any one of claims 1 to 7.

9. The EEG-based brain stimulation measurement and control integrated machine according to claim 8, characterized in that, An isolation circuit (30) is provided between the human-computer interaction device (20) and the brain stimulation measurement and control circuit (10).

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