Transcranial electrical stimulation device

Abstract

The invention discloses a transcranial electrical stimulation device, which belongs to the field of medical devices and comprises a current regulator, a voltage-current converter, a polarity switch, an electrode, a compensation unit and a signal generator; the current regulator generates a pulse voltage, and transmits the generated pulse voltage to the voltage-current converter, converts the pulse voltage signal into a current signal and transmits it to the polarity switch; the second output end of the signal generator transmits the generated DC voltage signal to the compensation unit, controls the conversion coefficient of the voltage-current converter to convert the DC voltage signal into an AC current of a specific frequency and amplitude; the first output end of the signal generator transmits the currents of different directions generated during a positive pulse period and a pulse stop period together through the polarity switch after positive and reverse polarity control to the electrode; the electrode outputs a unipolar current signal or a bipolar current signal or a unipolar and bipolar mixed current signal, and the device can stimulate the endorphin mechanism of the brain, and while improving the application efficiency, it also increases the safety of use.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to a transcranial electrical stimulation device. Background Art

[0002] A device for electronic sedation "Micro-LENAR" (SU, copyright certificate No. 1711914A61N 1 / 34, 1992), which includes a rhythmic action unit, a switch, an amplifier, an amplifier limiter, an amplitude regulator, a primary amplifier, a power amplifier, a protection unit, electrodes, an ammeter, a button, a resistor, a power supply and a timer.

[0003] In the device, the duration of the electrical stimulation is increased stepwise by switching the switch to the forward or reverse output of the rhythm action unit.

[0004] The disadvantage of this device is that the use of a switch to switch the pulse duration during treatment without observing the balance of positive and negative pulse energy will lead to jumps in the stimulation current amplitude and cause pain to the patient. In turn, this can lead to the activation of the patient's pressure limitation system, especially the release of glucocorticoids and cortisol, which will cause a jump in blood pressure, which will make the process less effective or even cause harm.

[0005] Another, transcranial electrical stimulation device (utility model RU 16826U1, А61N1 / 34, 2000), which includes a power supply, a current regulator, a rhythmic action unit, an amplifier, an ammeter and electrodes. In addition, it also includes a current stabilizer, a switch and an equivalent load, the power supply includes a battery, a voltage converter, a comparator, a battery voltage indicator and a voltage stabilizer. In addition, the first input of the voltage converter, the voltage regulator and the comparator is connected to the battery, and a generator is used as a rhythmic action unit. The output of the generator is connected through the amplifier, the ammeter, and the first output terminal of the connection electrode, at this time, the second input terminal of the comparator is connected to the output of the voltage regulator, and the equivalent load is connected to the second output terminal of the switch.

[0006] In this device, the generator produces unipolar rectangular pulses with a repetition period of T = 12.9 ± 0.4 ms, a duty cycle of K = 3.2 ... 3.7, and a leading edge and cutting duration of more than 20 μs. The voltage converter increases the battery voltage to a higher voltage, which is provided as a power supply to the amplifier. The use of an amplifier with current sensor feedback can reduce the dependence of the current intensity in the patient circuit on the varying load resistance (skin and internal tissue of the head). In this case, one electrode is in the forehead and the other is located on the hairless skin behind the ear. The comparator monitors the voltage of the battery and sends a signal about its discharge.

[0007] The device has the following disadvantages. Although the parameters of the device generally allow the activation of the endorphin mechanism of the brain, the use of unipolar rectangular pulses still presents a certain risk, since such pulses are known to have an average value within the period (constant component) equal to the quotient of the current amplitude A and the duty cycle of the pulse sequence K. The effect of direct current on skin and brain tissue can cause electrochemical burns on the skin and lead to temporary inactivation of brain neurons. In addition, the use of unipolar pulses does not allow the establishment of the necessary current intensity, since in order to achieve this intensity it is necessary to set the amplitude of the pulse to K times, which may exceed the patient's pain threshold. Summary of the invention

[0008] According to the problems existing in the prior art, the present invention discloses a transcranial electrical stimulation device, including a current regulator, a voltage-current converter, a polarity switch, electrodes, a compensation unit and a signal generator;

[0009] The current regulator generates a pulse voltage and transmits the generated pulse voltage to the voltage-current converter;

[0010] The voltage-current converter converts the pulse voltage signal into a current signal and transmits it to the polarity switch;

[0011] The signal generator includes a first output terminal and a second output terminal;

[0012] The second output terminal of the signal generator transmits the generated DC voltage signal to the input terminal of the compensation unit;

[0013] The compensation unit controls the conversion coefficient of the voltage-current converter to convert the DC voltage signal into an AC current of a specific frequency and amplitude;

[0014] At the same time, the first output end of the signal generator transmits the currents of different directions generated during the positive pulse period and the pulse stop period to the electrode after positive and negative polarity control through the polarity switch;

[0015] The electrode outputs a unipolar current signal or a bipolar current signal or a mixed unipolar and bipolar current signal.

[0016] Furthermore, the electrode includes electrode I and electrode II, electrode I is installed in the forehead occipital direction of the human body, and electrode II is installed behind the ear of the human body.

[0017] Furthermore, the positive pulse amplitude of the bipolar signal output by the electrode is 40% smaller than the amplitude of the unipolar signal.

[0018] Furthermore, the current value output by the current regulator shown ranges from 0 to 5 mA and the frequency ranges from 60 to 80 Hz.

[0019] Furthermore, the current regulator shown also includes a touch control module for parameter setting and key scanning, a signal generation module for generating current signals, a timing module for time setting, a display module for displaying ECG monitoring and pulse monitoring and real-time display of pulse parameters, and a threshold detection protection module for detecting current thresholds;

[0020] The signal generation module includes a low frequency module and a signal modulation module;

[0021] The timing module includes a time module, a stimulation time timing module and a pulse new point monitoring module;

[0022] The threshold detection protection module includes a frequency monitoring feedback module and a current amplitude feedback module.

[0023] Furthermore, it also includes a current detection module for detecting the current output by the current regulator. The current detection chip used by the current detection module is an INA286 bidirectional shunt detector.

[0024] Due to the adoption of the above-mentioned technical scheme, the present invention provides a transcranial electrical stimulation device, which can stimulate the endorphin mechanism of the brain, wherein the energy of the positive pulse must be compensated by a negative pulse of equal energy. At the same time, the device outputs a bipolar pulse current signal, which can generate a bipolar human body safety action current signal with an adjustable frequency of 60 to 80 Hz and an adjustable current amplitude of 0 to 5 mA, and ensure the safe use of the equipment, thereby improving the application efficiency and increasing the safety of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a module composition diagram of the present invention;

[0027] Figure 2 is a circuit diagram of a signal generator of the present invention;

[0028] Figure 3 is the circuit diagram of the current regulator;

[0029] Figure 4 It is a rectangular pulse power diagram;

[0030] Figure 5 Design the overall structure diagram for the current regulator software;

[0031] Figure 6 This is the program flow chart of the signal generation module;

[0032] Figure 7 This is the program flow chart of the timer module;

[0033] Figure 8 (a) is a schematic diagram of the current detection chip circuit of the current detection module;

[0034] Figure 8 (b) is a schematic diagram of the digital-to-analog circuit conversion of the current detection module;

[0035] Fig. 9 Timing diagram for the working of the present invention.

[0036] In the figure: 1. current regulator, 2. voltage-current converter, 3. polarity switch, 4. electrode, 5. compensation unit, 6. signal generator, 41. electrode I, 42. electrode II, 61. first output terminal, 62. second output terminal. DETAILED DESCRIPTION

[0037] In order to make the technical solutions and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention:

[0038] Figure 1 : is a module composition diagram of the present invention; a transcranial electrical stimulation device of the present invention comprises a current regulator 1, a voltage-current converter 2, a polarity switch 3, an electrode 4, a compensation unit 5 and a signal generator 6;

[0039] The current regulator 1 generates a pulse voltage and transmits the generated pulse voltage to the voltage-current converter 2;

[0040] The voltage-current converter 2 converts the pulse voltage signal into a current signal and transmits it to the polarity switch 3;

[0041] The signal generator 6 includes a first output terminal 61 and a second output terminal 62;

[0042] The second output terminal 62 of the signal generator 6 transmits the generated DC voltage signal to the input terminal of the compensation unit 5;

[0043] The compensation unit 5 controls the conversion coefficient of the voltage-current converter 2 to convert the DC voltage signal into an AC current of a specific frequency and amplitude;

[0044] At the same time, the first output terminal 61 of the signal generator 6 transmits the currents of different directions generated during the positive pulse period and the pulse stop period to the electrode 4 through the polarity switch 3 after positive and negative polarity control;

[0045] The electrode 4 outputs a monopolar current signal or a bipolar current signal or a monopolar and bipolar mixed current signal. The electrode 4 includes an electrode I 41 and an electrode II 42, wherein the electrode I 41 is arranged in the direction of the forehead occipital bone, and the electrode II 42 is arranged on the hairless skin behind the ear;

[0046] When the electrode 4 applies the output current of the device in the forehead-occipital direction, the signal generator 6 generates a rectangular pulse, which, combined with the forehead-occipital of the electrode 4, can activate the endorphin mechanism of the patient's brain. The polarity switch 3 changes the direction of the current in the electrode 4 in the following way: during the positive pulse from the first output terminal 61 of the generator 6, the direction of the current is from the occipital to the forehead, and from the forehead to the occipital during the pulse pause. In this case, the signal from the second output of the signal generator 6 is synchronously fed to the input terminal of the compensation unit 5, and the signal output from the compensation unit 5 is connected to the second input terminal of the voltage-current converter 2. The function of the compensation unit 5 is to control the conversion coefficient of the voltage-current converter 2 so that the positive and negative pulse energies are equal to avoid damage to the skin. Pulse energy = (current intensity) * (pulse duration); As a result, a current pulse sequence with different amplitudes is formed at the output of the voltage-current converter 2.

[0047] Figure 2 The circuit diagram of the signal generator of the present invention, wherein the circuit of the signal generator 6 includes an integrated operational amplifier U1, an integrated operational amplifier U2, an analog electronic switch U3, an integrated operational amplifier U4, a digital-to-analog converter A1, a field effect transistor Q1, a field effect transistor Q2, a field effect transistor Q3 and a field effect transistor Q4;

[0048] The VOUTA pin of the digital-to-analog converter A1 is connected to the positive input terminal of the integrated operational amplifier U1, the negative input terminal of the integrated operational amplifier U1 is connected to the ground through a series resistor R1 and a capacitor C2, the output terminal of the integrated operational amplifier U1 is connected to one end of the integrated operational amplifier Q2 through a capacitor C1 and a resistor R3 connected in parallel, the integrated operational amplifier Q2 is connected to the integrated operational amplifier Q1, the integrated operational amplifier Q1 is connected to the S1A pin of the analog electronic switch U3, the R pin of the analog electronic switch U3 is connected to the positive input terminal of the integrated operational amplifier U4, and the output terminal of the integrated operational amplifier U4 is also connected to the integrated operational amplifiers Q3 and Q4;

[0049] The model of the main control chip of the current regulator 1 is STM32F103c8t6. Figure 3The circuit diagram of the current regulator is shown below. It has three 16-bit timers, each with up to four channels for input capture / output comparison / PWM or pulse counting and incremental encoder input, 512K bytes of Flash program memory, etc. The special function registers of the main control chip are set through the software program to change the frequency and duty cycle of the pulse signal. The PWM output is connected to a voltage follower composed of an OP07 amplifier, which is used as an isolation circuit to protect the main control chip.

[0050] The digital amplitude is set by the main control chip and the analog amplitude is set through the DA converter A1. The channel width of the field effect tube Q1 and the field effect tube Q2 is controlled by the integrated operational amplifier U1 to realize the control of the current amplitude. The current is output by the main control chip with an adjustable frequency PWM control analog electronic switch A1, realizing that the constant current source is transformed into a pulse source. The pulse source controls the conduction of the field effect tube Q3 and the field effect tube Q4 to obtain a pulse current source with adjustable amplitude and controllable frequency. The rectangular pulse power supply diagram is shown as follows: Figure 4 As shown;

[0051] Figure 5 The overall structural block diagram of the current regulator software design is shown in FIG. The software part of the current regulator 1 includes five parts: a touch control module for parameter setting and key scanning, a signal generation module for generating current signals, a timing module for time setting, a display module for displaying ECG monitoring and pulse monitoring and real-time display of pulse parameters, and a threshold detection protection module for detecting the current threshold;

[0052] The signal generation module includes a low frequency module and a signal modulation module;

[0053] The timing module includes a time module, a stimulation time timing module and a pulse new point monitoring module;

[0054] The threshold detection protection module includes a frequency monitoring feedback module and a current amplitude feedback module.

[0055] The current regulator software adopts KeilμVision5 integrated development environment, uses C language for compilation, and uses ST-LINK for program download and debugging; the initialization program of the above module mainly includes: touch screen initialization, LCD display initialization, pulse detection initialization, timer initialization, serial port initialization, waveform generation initialization, etc. The main loop mainly runs the functional sub-functions that are important to the system, including: touch scanning subroutine, LCD display subroutine, DAC related configuration subroutine, etc.

[0056] (1) Signal generation module programming

[0057] Figure 6This is the program flow chart of the signal generation module. This device is designed to use two channels of DAC to output different frequencies and waveforms. Therefore, it is necessary to configure the built-in DAC digital-to-analog converter in the main control chip. First, enable the PORTA clock of the two output pins PA4 and PA5 of this design and set the pin initialization; then enable the DAC module clock and perform detailed configuration. The main configurations include using TIM to trigger DAC conversion function, enabling DAC's DMA function, and enabling DAC output to complete the DAC configuration.

[0058] First, initialize DMA, DAC, and TIM. After the transmission starts, the timer starts working, and the ARR counter starts counting from 0. When the count value reaches the set arr value, a trigger signal is generated, and DMA starts working. The data of the SineWave_Value address is transferred to the DAC output register DHR12R1, and the corresponding voltage is output, that is, the DAC output of one point is completed. The output of the next point is cycled. When the output of 128 points is completed, the waveform output of one cycle is completed, and then the output starts from the first address of SineWave_Value to prepare for the second cycle signal output. By changing the counting speed of the timer ARR counter, the frequency of the output waveform can be controlled, and the frequency setting and signal generation required for various physical therapy modes can be performed.

[0059] (2) Timer module programming

[0060] Figure 7 For the timer module program flow chart, the design selects TIM7 as the system's timer clock. The timer clock provides support for the countdown of the entire system operation. First, enable the TIM7 clock, set the automatic update interrupt to allow, and set the division factor to 72000, the automatic reload value to 100, and the counting frequency to 1000Hz. When 100 points are recorded, an interrupt is entered. When the number of interrupts reaches ten times, 1s is used for the countdown of the running mode.

[0061] Figure 8 (a) is a schematic diagram of the current detection chip circuit of the current detection module; Figure 8(b) is a schematic diagram of the digital-to-analog circuit conversion of the current detection module; the device must ensure the safety of the user. The device also includes a current detection module. The chip used in the current detection module includes INA286AID. The final output current of the current regulator needs to be limited to a certain extent. The maximum current value cannot exceed 5mA. The current size at the output end of the current regulator needs to be detected. The current detection chip inside the current detection module uses INA286 bidirectional shunt detector to collect current and convert it into voltage data. A 5-ohm resistor is connected in series at the signal output end to perform differential sampling on both ends of the resistor. The reference voltage of the current detection chip is 5V. According to the data sheet, its differential voltage amplification factor is 100 times, so its current measurement range is -5~5mA. The voltage signal is then transmitted to a 12-bit 4-channel serial output sampling analog-to-digital converter ADS7841 to be converted into a digital signal, and the collected current data is judged.

[0062] Fig. 9 A time chart for the work of the present invention; Fig. 9 The signal at the output of the signal generator 6 shown is a pulse train in which a pulse is represented by the number I and a pause between pulses is represented by the number II. The average graph shows the signal at the output of the voltage-to-current converter 2, where S1 is the energy of pulse I, which is equal to the product of (current intensity)*(pulse duration), and S2 is the energy of pulse II, which is equal to the product of (current intensity)*(pause duration). In this case, the energies of pulses I and II should be the same. The bottom graph shows the output signal of the polarity switch 3, which is supplied to the electrode 4, where S1 is the energy of the positive pulse I and S2 is the energy of the negative (inverted) pulse II. Since the energies of the positive and negative pulses are equal, the average current for this cycle will be zero.

[0063] In addition, it should be noted that for unipolar signals and bipolar signals having equal effective values ​​of current intensity, for these signal generator parameters, the positive pulse amplitude of the bipolar signal (at the output of polarity switch 3) is 40% smaller than the amplitude of the unipolar signal. Since the skin receptors on the user's head can accurately respond to the amplitude of the pulse, the use of a bipolar signal can use a 40% higher current intensity with the same sensation, thereby improving the efficiency of the device.

[0064] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A transcranial electrical stimulation device, characterized in that: The invention comprises a current regulator (1), a voltage-current converter (2), a polarity switch (3), an electrode (4), a compensation unit (5) and a signal generator (6); the current regulator (1) generates a pulse voltage and transmits the generated pulse voltage to the voltage-current converter (2); the voltage-current converter (2) converts the pulse voltage signal into a current signal and transmits it to the polarity switch (3); the signal generator (6) comprises a first output terminal (61) and a second output terminal (62); the second output terminal (62) of the signal generator (6) converts the generated pulse voltage into a current signal. The generated DC voltage signal is transmitted to the input end of the compensation unit (5); the compensation unit (5) controls the conversion coefficient of the voltage-current converter (2) to convert the DC voltage signal into an AC current with a specific frequency and amplitude; at the same time, the first output end (61) of the signal generator (6) transmits the currents of different directions generated during the positive pulse period and the pulse stop period to the electrode (4) after positive and negative polarity control through the polarity switch (3); the electrode (4) outputs a unipolar current signal or a bipolar current signal or a unipolar and bipolar mixed current signal; The current regulator (1) also includes a touch control module for parameter setting and key scanning, a signal generation module for generating current signals, a timing module for time setting, a display module for displaying electrocardiogram monitoring and pulse monitoring and real-time display of pulse parameters, and a threshold detection protection module for detecting current thresholds; The signal generation module includes a low frequency module and a signal modulation module; The timing module includes a time module, a stimulation time timing module and a pulse new point monitoring module; The threshold detection protection module includes a frequency monitoring feedback module and a current amplitude feedback module; The signal generation module first enables the PORTA clocks of the two output pins PA4 and PA5 and sets the pin initialization; then enables the DAC module clock, uses the TIM to trigger the DAC conversion function, enables the DAC DMA function, and enables the DAC output, so as to complete the DAC configuration work; First, initialize DMA, DAC, and TIM. After the transmission starts, the timer starts working, and the ARR counter starts counting from 0. When the count value reaches the set arr value, a trigger signal is generated, and DMA starts working. The data of the SineWave_Value address is transferred to the DAC output register DHR12R1, and the corresponding voltage is output, that is, the DAC output of one point is completed, and the output of the next point is cycled. When the output of 128 points is completed, the waveform output of one cycle is completed, and the output starts from the first address of SineWave_Value, and the second cycle signal output is prepared. By changing the counting speed of the timer ARR counter, the output waveform frequency can be controlled, and the frequency setting and signal generation required for various physical therapy modes can be performed; The electrode (4) comprises an electrode I (41) and an electrode II (42), wherein the electrode I (41) is installed in the forehead occipital direction of the human body, and the electrode II (42) is installed behind the ear of the human body.

2. A transcranial electrical stimulation device according to claim 1, characterized in that: The positive pulse amplitude of the bipolar signal output by the electrode (4) is 40% smaller than the amplitude of the unipolar signal.

3. A transcranial electrical stimulation device according to claim 1, characterized in that: The current value output by the current regulator (1) ranges from 0 to 5 mA and the frequency ranges from 60 to 80 Hz.

4. A transcranial electrical stimulation device according to claim 1, characterized in that: It also comprises a current detection module for detecting the current output by the current regulator (1), and the current detection chip used by the current detection module is an INA286 bidirectional current shunt detector.

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