Portable idiopathic tremor myoelectricity feature extraction device

Abstract

The invention discloses a portable idiopathic tremor myoelectricity feature extraction device which comprises an acquisition body, a hydrogel electrode and a signal display device. A hydrogel electrode is adopted to collect idiopathic tremor electromyographic signals, and the hydrogel electrode is made of an elastic material and can adapt to different curve surfaces. Meanwhile, water molecules on the surface of the hydrogel electrode and the skin surface have a good adsorption effect. Therefore, the stability and the accuracy of electromyographic signal transmission are ensured. Meanwhile, the hydrogel electrode is connected with the device in a magnetic attraction manner, so that the replaceability of the hydrogel is improved. The method is suitable for signal feature extraction of tremor electromyographic signals of an idiopathic tremor patient, facilitates real-time recording of idiopathic tremor signal features of the idiopathic tremor patient, and can provide a theoretical basis for treatment of the idiopathic tremor patient.

Description

Technical Field

[0001] This invention relates to an electromyography (EMG) signal acquisition device, specifically a portable device for extracting EMG features of essential tremor. Background Technology

[0002] Electromyography (EMG) signal acquisition refers to the technology of real-time or offline monitoring and recording of the electrical activity of human muscles using an EMG signal acquisition device. EMG signals are generated by the bioelectrical signals produced when muscle fibers move due to muscle contraction. The EMG signal acquisition device collects these bioelectrical signals through surface electrodes and converts them into digital signals for analysis and processing. EMG signal acquisition devices have a wide range of applications, including human-computer interaction, rehabilitation training, and ergonomics research.

[0003] In the field of electromyography (EMG) signal acquisition for patients with essential tremor, the real-time nature and high-quality acquisition of EMG signals directly determine the accuracy of EMG signal characteristic data. Currently, there is no device specifically designed for real-time feature extraction of EMG signals from patients with essential tremor. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a portable electromyography feature extraction device for essential tremor, which is suitable for extracting signal features of tremor electromyography signals from patients with essential tremor. It is beneficial for real-time recording of the signal features of essential tremor patients and can provide a theoretical basis for the treatment of patients with essential tremor.

[0005] The technical solution of the present invention is: a portable electromyography feature extraction device for essential tremor, comprising a data acquisition body, a hydrogel electrode and a signal display device;

[0006] The back of the collecting body is provided with two circular magnets, and each of the two circular magnets has a circular electrical connection hole in its center;

[0007] The hydrogel electrode is made of elastic material. The front of the hydrogel electrode can be applied to the skin surface and adapt to different curved surfaces. The back of the hydrogel electrode is provided with two circular metal magnets, and the center of each of the two circular metal magnets is provided with a circular electrical connection post of the hydrogel electrode.

[0008] The two circular electrical connection posts on the back of the hydrogel electrode can be inserted into the two circular electrical connection holes on the back of the acquisition body to realize the interchangeability of the electrode and wireless connection. The hydrogel electrode and the acquisition body are fixedly connected by the magnetic attraction of the circular magnet and the circular metal magnet.

[0009] The signal display device interacts with the acquisition subject via Bluetooth communication to achieve real-time output of electromyographic characteristic signals.

[0010] Furthermore, the acquisition unit includes a Bluetooth processing chip, a switching module, a DC noise isolation circuit, a dual-channel low-pass filter circuit, a differential signal amplification circuit, a signal processing circuit, a rechargeable lithium battery, and a power management module.

[0011] in,

[0012] The Bluetooth processing chip is connected to the signal display device for wireless communication and communicates with the signal processing circuit through a serial interface.

[0013] The switch module sends acquisition commands to achieve real-time control of the acquisition;

[0014] The DC noise isolation circuit is used to isolate external DC noise, which can effectively suppress the interference of DC noise on the acquired signal.

[0015] The dual-channel low-pass filter circuit is used to filter out power frequency noise and other noise from electromyographic signals.

[0016] The differential amplifier circuit is used to amplify the filtered small signal, and the differential form further suppresses the coupling interference of ambient noise on the signal.

[0017] The signal processing circuit acquires and transmits electromyographic signals according to the instructions sent by the Bluetooth processing chip.

[0018] The rechargeable lithium battery provides power to all circuits in the entire system;

[0019] The power management module adapts to the voltage and current requirements of each module by changing the power supply voltage of the rechargeable lithium battery.

[0020] Furthermore, the signal display device is a mobile phone or a computer.

[0021] Furthermore, in the dual-channel low-pass filter circuit, the cutoff frequency is adjusted by designing the values ​​of the low-pass filter R and C, and is set between 12Hz and 50Hz to ensure that the tremor frequency of patients with essential tremor can pass through, while suppressing power frequency and other noise to the maximum extent.

[0022] The cutoff frequency formula is as follows:

[0023] 12Hz <f=1 / 2*π*R*C<50Hz。

[0024] The beneficial effects of this invention are: it provides a portable electromyography (EMG) feature extraction device for essential tremor, using hydrogel electrodes to collect EMG signals of essential tremor. The hydrogel electrodes are made of elastic material and can adapt to different curved surfaces. Simultaneously, water molecules on the surface of the hydrogel electrodes exhibit good adsorption with the skin surface. Therefore, it ensures the stability and accuracy of EMG signal transmission. Furthermore, the hydrogel electrodes are connected to the device magnetically, increasing the replaceability of the hydrogel.

[0025] This invention employs a DC noise isolation circuit, namely a series capacitor, to isolate DC noise input from the skin, allowing the vibration AC signal to pass through, which greatly improves the accuracy of signal acquisition.

[0026] This invention employs a dual-channel low-pass filter circuit to filter out front-end noise from electromyographic signals. According to the "Guidelines for the Diagnosis and Treatment of Essential Tremor in China (2020)," the tremor frequency of patients with essential tremor is 4–12 Hz, while power line interference is 50 Hz. By designing the values ​​of R and C in the low-pass filter to adjust the cutoff frequency and setting it between 12 Hz and 50 Hz, the tremor frequency of patients with essential tremor can pass through, while maximally suppressing power line interference and other noise.

[0027] This invention employs a differential amplifier circuit to amplify the small front-end signal, with an amplification factor of 6. The differential form further suppresses the coupling of ambient noise to the acquired signal, i.e., amplifies the differential signal and suppresses the common-mode signal. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the device for extracting electromyographic features of essential tremor.

[0029] Figure 2 This is a hardware flowchart of an electromyography feature extraction device for essential tremor.

[0030] Figure 3 Circuit diagram of a test model for an electromyographic feature extraction device for essential tremor;

[0031] Figure 4 A screenshot of the actual waveform characteristics of the acquired 50uV / 12Hz sine wave signal;

[0032] Figure 5 A screenshot of the actual waveform characteristics of the acquired 50uV / 4Hz sine wave signal;

[0033] Figure 6 A screenshot of the actual waveform characteristics of the acquired 5mV / 12Hz sine wave signal;

[0034] Figure 7 This is a screenshot of the actual waveform characteristics of the acquired 5mV / 4Hz sine wave.

[0035] In the diagram: 1 is the main data acquisition unit, 2 is the hydrogel electrode, 3 is the circular magnet, and 4 is the circular metal magnet. Detailed Implementation

[0036] The present invention will now be further described with reference to the accompanying drawings.

[0037] like Figure 1 As shown, a portable electromyography feature extraction device for essential tremor includes a data acquisition body 1, a hydrogel electrode 2, and a signal display device.

[0038] The back of the collecting body 1 is provided with two circular magnets 3, and each of the two circular magnets 3 has a circular electrical connection hole in its center.

[0039] The hydrogel electrode 2 is made of elastic material. The front of the hydrogel electrode 2 can be applied to the skin surface and adapt to different curved surfaces. The back of the hydrogel electrode 2 is provided with two circular metal magnets 4, and a circular electrical connection post of the hydrogel electrode is provided in the center of each of the two circular metal magnets 4.

[0040] The two circular electrical connection posts on the back of the hydrogel electrode 2 can be inserted into the two circular electrical connection holes on the back of the acquisition body 1 to achieve electrode interchangeability and wireless connection. The hydrogel electrode 2 and the acquisition body 1 are fixedly connected by the magnetic attraction of the circular magnet 3 and the circular metal magnet 4.

[0041] The signal display device interacts with the acquisition subject via Bluetooth communication to achieve real-time output of electromyographic characteristic signals.

[0042] This invention employs hydrogel electrodes to acquire electromyographic signals of essential tremor. The hydrogel electrodes are made of an elastic material that can adapt to different surface curves. Simultaneously, water molecules on the surface of the hydrogel electrodes exhibit good adsorption to the skin surface. Therefore, the stability and accuracy of electromyographic signal transmission are ensured. Furthermore, the hydrogel electrodes are connected to the device magnetically, increasing the interchangeability of the hydrogel.

[0043] like Figure 2 As shown, the acquisition unit 1 includes a Bluetooth processing chip, a switching module, a DC noise isolation circuit, a dual-channel low-pass filter circuit, a differential signal amplification circuit, a signal processing circuit, a rechargeable lithium battery, and a power management module.

[0044] in,

[0045] The Bluetooth processing chip is connected to the signal display device for wireless communication and communicates with the signal processing circuit through a serial interface.

[0046] The switch module sends acquisition commands to achieve real-time control of the acquisition.

[0047] The DC noise isolation circuit is used to isolate external DC noise and can effectively suppress the interference of DC noise on the acquired signal.

[0048] The dual-channel low-pass filter circuit is used to filter out power frequency noise and other noise from electromyographic signals.

[0049] The differential amplifier circuit is used to amplify the filtered small signal, and the differential form further suppresses the coupling interference of ambient noise on the signal.

[0050] The signal processing circuit acquires and transmits electromyographic signals according to the instructions sent by the Bluetooth processing chip.

[0051] The rechargeable lithium battery provides power to all circuits in the entire system.

[0052] The power management module adapts to the voltage and current requirements of each module by changing the power supply voltage of the rechargeable lithium battery.

[0053] This invention employs a DC noise isolation circuit, namely a series capacitor, to isolate DC noise input from the skin, allowing the vibration AC signal to pass through, which greatly improves the accuracy of signal acquisition.

[0054] This invention employs a dual-channel low-pass filter circuit to filter out front-end noise from electromyographic signals. According to the "Guidelines for the Diagnosis and Treatment of Essential Tremor in China (2020)," the tremor frequency of patients with essential tremor is 4–12 Hz, while power line interference is 50 Hz. The cutoff frequency is adjusted by designing the values ​​of R and C in the low-pass filter and setting it between 12 Hz and 50 Hz to ensure that the tremor frequency of patients with essential tremor can pass through while maximally suppressing power line interference and other noise. The cutoff frequency formula is as follows:

[0055] 12Hz <f=1 / 2*π*R*C<50Hz。

[0056] This invention employs a differential amplifier circuit to amplify the small front-end signal, with an amplification factor of 6. The differential form further suppresses the coupling of ambient noise to the acquired signal, i.e., amplifies the differential signal and suppresses the common-mode signal.

[0057] This invention employs a signal processing circuit for synchronous sampling of the front-end amplified signal, wherein the internal 24-bit ADC converts the input analog signal into a digital signal and transmits it to the Bluetooth processing chip;

[0058] The Bluetooth processing chip of this invention communicates with the signal processing module via a serial interface, and outputs the received essential tremor characteristic signal to a mobile app via Bluetooth communication. It is generally displayed as a digital value, which can be converted into a voltage value, i.e., signal strength, using a formula. The formula is as follows:

[0059]

[0060] Vpp: Signal strength, in mV;

[0061] Amax: The maximum value of a periodic signal, expressed as a digital value;

[0062] Amin: The minimum value of a periodic signal, expressed as a digital value;

[0063] VREF: The reference voltage for the signal processing module, a fixed value of 2.42V;

[0064] GAIN: Magnification 6x.

[0065] Figure 2 A rechargeable lithium battery powers the entire system, and power management converts the battery voltage to the voltage required by each module. Upon receiving a power-on command, the switch module powers on the main system. Manual triggering of the switch module again sends a start-of-acquisition command to the Bluetooth chip. Upon receiving the command, the Bluetooth chip begins interacting with the signal processing integrated circuit via SPI, sending the acquired data to a mobile app. The mobile app communicates with the main system via Bluetooth. The hydrogel electrode acquires a simulated vibration signal, which includes power frequency interference and other noise. The simulated vibration signal passes through a capacitor to isolate DC noise. After the first stage of processing, the signal flows into the subsequent circuit. The signal then passes through an RC low-pass filter circuit, which performs a second stage of processing to further suppress power frequency noise. The signal is then input to a differential amplifier circuit, which first suppresses common-mode noise and then amplifies the acquired useful vibration signal. This useful vibration signal is then transmitted to the acquisition signal processing integrated circuit, which performs a real-time ADC conversion of the simulated vibration signal into a digital quantity. After receiving instructions from the Bluetooth processing chip, the signal processing integrated circuit sends the acquired data to the Bluetooth processing chip via SPI, and the Bluetooth processing chip simultaneously synchronizes this data to the application. This entire process is real-time.

[0066] The actual acquisition effect of the device of the present invention is to use a signal generator to simulate the corresponding frequency of the jitter signal. The minimum amplitude of the current signal generator is 1mV. Therefore, the signal generator is reduced by 100 times through a resistor divider to achieve the required jitter signal intensity.

[0067] The signal generator amplitude is set to 5mV, which is then reduced by 100 times through a resistor, resulting in a 50uV input to the device. The device is connected to a PC via Bluetooth, and the PC records the signal in real time and outputs the signal characteristics.

[0068] like Figure 3Test model circuit: In the figure, R1 = 10 * R2, and R1 and R2 can be selected as needed;

[0069] The actual waveform characteristics of the collected 50uV / 12Hz, 50uV / 4Hz, 5mV / 12Hz, and 5mV / 4Hz sinusoidal signals are shown in the screenshot below. Figure 4-7 As shown in the figure. The horizontal axis represents the signal acquisition point, and the vertical axis represents the signal strength.

[0070] From the above acquisition characteristics, the jitter frequency and jitter amplitude can be obtained. It can be observed that the waveform characteristics of the 4Hz / 50uV and 12Hz / 50uV small signals have small distortion and can be identified. Furthermore, the greater the jitter intensity, the better the signal.

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A portable device for extracting electromyographic features of idiopathic tremor, characterized in that: It includes a data acquisition unit (1), a hydrogel electrode (2), and a signal display device; The back of the collecting body (1) is provided with two circular magnets (3), and each of the two circular magnets (3) has a circular electrical connection hole in its center; The hydrogel electrode (2) is made of elastic material. The front of the hydrogel electrode (2) can be applied to the skin surface and adapt to different curved surfaces. The back of the hydrogel electrode (2) is provided with two circular metal magnets (4). The center of each of the two circular metal magnets (4) is provided with a circular electrical connection post of the hydrogel electrode. The two circular electrical connection posts on the back of the hydrogel electrode (2) can be inserted into the two circular electrical connection holes on the back of the acquisition body (1) to realize the interchangeability of the electrode and wireless connection. The hydrogel electrode (2) and the acquisition body (1) are fixedly connected by the magnetic attraction of the circular magnet (3) and the circular metal magnet (4). The signal display device interacts with the acquisition subject via Bluetooth communication to achieve real-time output of electromyographic characteristic signals.

2. The portable electromyographic feature extraction device for idiopathic tremor according to claim 1, characterized in that: The acquisition unit (1) includes a Bluetooth processing chip, a switching module, a DC noise isolation circuit, a dual-channel low-pass filter circuit, a differential signal amplification circuit, a signal processing circuit, a rechargeable lithium battery, and a power management module. in, The Bluetooth processing chip is connected to the signal display device for wireless communication and communicates with the signal processing circuit through a serial interface. The switch module sends acquisition commands to achieve real-time control of the acquisition; The DC noise isolation circuit is used to isolate external DC noise, which can effectively suppress the interference of DC noise on the acquired signal. The dual-channel low-pass filter circuit is used to filter out power frequency noise and other noise from electromyographic signals. The differential amplifier circuit is used to amplify the filtered small signal, and the differential form further suppresses the coupling interference of ambient noise on the signal. The signal processing circuit acquires and transmits electromyographic signals according to the instructions sent by the Bluetooth processing chip. The rechargeable lithium battery provides power to all circuits in the entire system; The power management module adapts to the voltage and current requirements of each module by changing the power supply voltage of the rechargeable lithium battery.

3. The portable electromyographic feature extraction device for idiopathic tremor according to claim 2, characterized in that: The signal display device is a mobile phone or a computer.

4. The portable electromyographic feature extraction device for idiopathic tremor according to claim 2, characterized in that: In the dual-channel low-pass filter circuit, the cutoff frequency is adjusted by designing the values ​​of the low-pass filter R and C, and is set between 12Hz and 50Hz to ensure that the tremor frequency of patients with essential tremor can pass through, while suppressing power frequency and other noise to the maximum extent. The cutoff frequency formula is as follows: 12Hz <f=1 / 2*π*R*C<50Hz。

Images