CN102921105B - In-vitro test stimulator - Google Patents

Abstract

The utility model relates to a test stimulator for external use, which belongs to the technical field of implantable medical instruments and is mainly used for the test of nerve electrical stimulation therapy. The present invention provides an in vitro test stimulator with a dual-channel pulse output with a user interface, which can output precise parameter-adjustable electrical stimulation pulses, and is used for therapeutic testing or short-term testing of patients during implantable neurostimulator surgery. electrical stimulation therapy experience. It is characterized in that: the test stimulator adopts an integrated structure design, which is mainly composed of a shell, a toggle switch, a membrane button, a display screen, a battery, a printed circuit board, etc., and has a small and simple appearance; the pulse parameters can be adjusted through the buttons and switches, It is intuitive and convenient to test the electrode load impedance and set the electrode contact polarity; the self-locking function and anti-misoperation design can effectively prevent misoperations during use by patients, and is safe and reliable. The test stimulator can be widely used for test evaluation and experience of various nerve electrical stimulation treatments.

Description

in vitro test stimulator

technical field

The invention is an in vitro test stimulator used by doctors or patients to test and evaluate during implantable electrical stimulation therapy operations, and belongs to the technical field of implantable medical instruments.

Background technique

At present, implantable electrical stimulation systems have been widely used in the treatment of neurological diseases. For example, deep brain stimulation devices (brain pacemakers) are often used to treat motor disorders such as Parkinson's disease. Spinal cord stimulators can effectively improve chronic Pain, wait. The composition of the implantable electrical stimulation system generally includes an implantable pulse generator, one or more electrodes, and extension wires connecting the pulse generator and the electrodes. Among them, the pulse generator is the core part of the system, used to generate electrical stimulation pulses with adjustable parameters (such as amplitude, frequency, pulse width, etc.) In the target stimulation target, it plays a role in regulating nerves.

Taking the implantation of a brain pacemaker as an example, the surgical process of implanting an electrical stimulation system can generally be described as: before implanting a pulse generator, first use magnetic resonance scanning and stereotaxic techniques to precisely position and find an accurate stimulation target. After point coordinates, electrodes are implanted in the brain. The process is minimally damaging, and since the brain has no pain perception, the patient feels no pain. The subsequent implantation of the pulse generator and placement of the extension wires involved several relatively invasive surgical procedures, such as tunneling under the skin with special instruments. Before implanting the pulse generator, the doctor connects the electrodes to the pulse output port of the test stimulator through the test wires, and conducts preliminary tests, such as asking the patient to do some simple actions, such as holding a cup, stretching the arm, drawing a spiral line, etc. According to the patient's feelings and improvement of symptoms, further adjust the electrode position and stimulation parameters to achieve the best therapeutic effect. If the patient's symptoms are controlled during the test, doctors can go further and implant the entire brain pacemaker system. The specific operation is to implant a pulse generator under the skin under the clavicle of the chest, and then connect the pulse generator to the electrodes through an extension wire under the skin. This process can be carried out immediately, or it can be observed after several days. For example, patients may request to experience electrical stimulation therapy for a period of time before undergoing surgery to implant pulse generators and assemble subcutaneous extension wires, so as to determine whether the therapy is suitable. Effectively inhibit symptoms, and whether there are side effects, and if so, whether it is acceptable. This testing experience phase can last anywhere from a few hours to thirty days.

If the implanted pulse generator is directly used for testing, the main problem is that the cost is too high. The pulse generator is a one-time-use sterile medical device. Once the sterile package is opened, the patient needs to pay more than 100,000 yuan for the purchase. If the curative effect is not satisfied, it will form a huge waste. In addition, setting the parameters of the pulse generator requires the remote control of the external program controller, which causes inconvenience for doctors and patients in operation, and it is impossible to intuitively read the working status and pulse parameters of the pulse generator. The medical pulse generators available on the market are often relatively large in size, which is not easy for patients to carry and affects the free activities of patients. The pulse waveform, parameters and accuracy of their output may not meet the needs of clinical use.

In response to these problems, this patent has invented an in vitro test stimulator with a user interface and a dual-channel pulse output for test evaluation, which can not only provide precise parameter-adjustable electrical pulses for the test stage, but also has a small and beautiful structure and is easy to operate. Simple and convenient, easy to carry. The electrode load impedance test function can assist in judging the accuracy of stimulation target positioning, judging whether the electrodes can work normally, and estimating the service life of the implanted stimulator. Although the structural design of the test stimulator does not distinguish between doctors and patients, it has a design to prevent misuse. For example, the switches used to select the electrode contact polarity combination and stimulation mode are only allowed to be operated by doctors. A leather case can be designed to cover the area where these switches are located to prevent misoperation during the patient test. The leather case is on the display screen. It is designed to be transparent and will not affect the reading of the current working state of the test stimulator. In addition, the self-locking gear of the power switch of the test stimulator can shield the function of the parameter adjustment button, and this design also plays a role in preventing the button from being pressed by mistake.

Contents of the invention

The purpose of the present invention is to provide a dual-channel pulse output external test stimulator with a user interface, which can provide patients with precise parameter-adjustable electrical stimulation pulses during the testing and experience phase of electrical stimulation therapy. The test stimulator has a number of control buttons and toggle switches with different functions and an LCD display, which can intuitively program the parameters of the dual-channel output pulse and test the electrode load impedance, which enhances the convenience and intuitiveness of operation , Its locking function and anti-misoperation design effectively prevent misoperations by patients and doctors, and enhance reliability and safety.

An in vitro test stimulator for test evaluation of electrical nerve stimulation therapy, characterized in that it contains: a pulse parameter setting device, an output control device, a display device, a microcontroller, a pulse output circuit module, a power supply, a power management circuit and an operation A mode switch component, where:

The pulse parameter setting device is used to generate one of the following command signals: amplitude upward adjustment, amplitude downward adjustment, frequency upward adjustment, frequency downward adjustment, pulse width upward adjustment, pulse width downward adjustment, electrode impedance test;

The output control device is used to set the power switch state and user operation mode, and is also used to set the polarity combination of each electrode contact under each channel, as well as to select the stimulation mode and the channel that is valid for the current parameter setting;

The display device is used to display the current pulse output parameters, electrode impedance test results, and warning information when the power supply is insufficient;

Pulse output circuit module, including: voltage modulation circuit, pulse output control circuit, charge balance circuit and electrode impedance test circuit;

Microcontroller, which can receive the instruction signal output by the pulse parameter setting device, and can also receive the signal output by the output control device, output instructions and data for display to the display device, and monitor the pulse output The output of the circuit module;

in,

The test stimulator has a first operation mode suitable for doctor's operation and a second operation mode suitable for patient operation, the operation mode switching part is used to switch the operation mode of the test stimulator, in the first operation In the first mode, the doctor can set the operating parameters of the test stimulator, in the second mode of operation, the patient can only view the display and readings of the display device.

Preferably, the operation mode switching component is a self-locking gear of the power switch gear, and a leather sheath provided outside the casing of the test stimulator.

Preferably, the test stimulator is suitable for use outside the body, the pulse parameter setting device includes control buttons, the output control device includes a toggle switch, and the power supply is a battery.

Preferably, the display content of the display device includes: the amplitude, frequency, pulse width and unit of the output pulse of the test stimulator, the electrode impedance test result, the electrode impedance of each channel, and the low voltage alarm information of the power supply.

Preferably, the polarity of the electrode contacts is selected from "+", "-" and "0", and the stimulation mode is a constant current mode or a constant voltage mode.

Preferably, the pulse output control circuit works in constant voltage mode or constant current mode according to the stimulation mode set by the output control device, and in the constant voltage mode, the voltage output by the pulse output circuit module The amplitude is 0-10V, and in the constant current mode, the current intensity output by the pulse output circuit module is 0-25mA.

Preferably, after each pulse electrical signal output by the pulse output circuit module, the charge balance circuit generates a reverse balanced pulse electrical signal;

The electrode impedance test circuit can measure the load impedance of the electrode connected to the test stimulator;

The power management circuit contains:

A voltage stabilizing circuit, which stabilizes the output voltage of the battery at a set value, and supplies power for the microcontroller and the display screen;

Self-locking circuit, used to lock the working state of the test stimulator and turn off the button function;

The power supply voltage sampling circuit is used to detect the power supply voltage at regular intervals, and if the voltage value is lower than the set threshold value, the microcontroller will issue a low voltage alarm through the display device.

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

(1) Integrated structural design, small and beautiful appearance, convenient and reliable operation, and a design to prevent misoperation;

(2) Dual-channel programmable parameter pulse output, providing high-precision electrical pulse signals for the testing phase of electrical stimulation therapy;

(3) It can accurately test the electrode load impedance, which can assist in judging the accuracy of stimulation target positioning, judging whether the electrodes are working normally, and estimating the service life of the implanted stimulator;

(4) Use ordinary dry batteries for power supply, which increases the convenience of use;

(5) It has a wide range of uses and can be used for testing various types of implantable electrical nerve stimulators during operation. The present invention has extremely high economic and social benefits.

Description of drawings

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Figure 1 is a schematic diagram of the method of use of the test stimulator.

Fig. 2 is a schematic diagram of the electric pulse when the test stimulator dual-channel pulse output.

Fig. 3 is a schematic diagram of a specific structure and composition scheme of the test stimulator.

Fig. 4 is a specific information display scheme of the display screen of the test stimulator.

Fig. 5 is a block diagram of the circuit principle of the test stimulator.

Figure 6 is a block diagram of a test stimulator electrode impedance test.

Detailed ways

The test stimulator is composed of a shell, a toggle switch, a membrane button, a display screen, a battery, a printed circuit board and the like. in:

The shell is composed of a shell and a shell cover, and the shell cover can be opened to replace the battery.

Switches, buttons and display screens provide human-computer interaction channels. The test stimulator has eleven toggle switches, of which: one power switch is a single-pole three-throw switch, which is used to test the on-off of the power supply of the stimulator and the working status of the test stimulator. locking;

Two single-pole double-throw switches are used to select the stimulation mode and the channel that is valid for the current parameter setting; in addition, there are eight single-pole three-throw switches used to select the polarity of the eight electrode contacts in two channels. Can be set as positive, negative and empty respectively. The seven membrane buttons are used for the upward and downward adjustment of the electric pulse amplitude, frequency and pulse width, and electrode impedance testing. The test stimulator also has a display screen, which is used to display the basic parameters of the electric pulse output by the test stimulator, the electrode impedance test result, and display an alarm message when the battery voltage is insufficient.

The power supply battery is two common dry batteries, which can be easily replaced.

The printed circuit board implements various functions such as the pulse output of the test stimulator. The printed circuit board uses a microcontroller as the core, including power management circuits, key input and indication control circuits, and pulse output circuits. The functions realized by the microcontroller include: key input response, control display screen, control pulse output circuit, etc. The power management circuit includes a voltage stabilizing circuit and a locking circuit. The voltage stabilizing circuit lowers the battery output to 3.3V to supply power to control circuits such as microcontrollers. The locking circuit locks the current working state of the test stimulator and shields the parameter adjustment button function. The pulse output circuit is used to generate electrical stimulation pulses consistent with the set parameters.

FIG. 1 shows a schematic diagram of the use and operation of the test stimulator 1, taking deep brain stimulation as an example. When in use, the test stimulator 1 is placed outside the body, and the generated electrical pulse signals are sequentially sent to the stimulating electrodes 3 implanted in the deep part of the patient's brain through the test wire interface 4 and the test wire 2 .

The test stimulator can generate one or two electrical pulse signals through button operation. Figure 2 shows the pulse signal when two pulse outputs are generated. The amplitude and pulse width of channel 1 and channel 2 pulses can be controlled by the switch and The buttons are adjusted independently, the frequency of the two channels is the same, and they are separated in time sequence. After each stimulation electric pulse 59 of each channel is output, a reverse low-amplitude pulse 60 will be generated after a short time delay (about 200 μs) , to achieve the charge balance of the stimulation target and avoid damage to the target tissue. The function of the short-time delay is to make the stimulation pulse fully act on the target and avoid weakening the physiological effect of the stimulation. The pulse width and amplitude of the reverse discharge pulse do not need to be the same as the stimulation pulse, and the corresponding response should be as small as possible to avoid being perceived by the patient and affecting the therapeutic effect of the stimulation pulse. Here, the amplitude and pulse width of the reverse discharge pulse are variable. For example, when the stimulation pulse frequency is low, the pulse width of the discharge pulse increases slightly (correspondingly, the amplitude of the discharge pulse decreases slightly). And when the stimulation pulse frequency increases, the pulse width of the discharge pulse decreases slightly (correspondingly, the amplitude of the discharge pulse increases slightly).

The parameter settings of the test stimulator output stimulation pulse include: amplitude, pulse width, frequency, and electrode contact and polarity selection, so as to provide a variety of stimulation combinations. The range of stimulation electric pulse amplitude adjustment is 0~10V in constant voltage stimulation mode, 0~25mA in constant current stimulation mode; frequency adjustment range is 2~250Hz; pulse width adjustment range is 30~450us, and in constant voltage mode 266,600 stimulation parameter combinations, 666,500 in constant current mode. The clinician can choose the appropriate combination of stimulation parameters according to the actual situation of the patient. In addition, the stimulation parameters need to be fine-tuned according to the test effect of the patient and the response of the patient, so as to select the optimal combination of stimulation parameters and achieve the best therapeutic effect.

Figure 3 shows a specific structure and composition of the test stimulator. Wherein (a) is a schematic diagram of the front of the test stimulator, (b) is a schematic diagram of the back and internal structure of the test stimulator, and (c) is a schematic diagram of the top surface of the test stimulator. The test stimulator includes a shell 5, a surface film 6, and the human-computer interaction part of the test stimulator includes a power supply and a lock switch 33, ten toggle switches (8, 9, 10, 11, 12, 13, 14, 15, 16, 17 ), seven membrane keys (18, 19, 20, 21, 22, 23, 24), and a display screen 7. Power supply and lock switch 33 are single-pole three-throw switches, and three positions of the switch correspond to power supply off (○), power supply on (I), and locked state ( ), the output of the test stimulator is locked in the locked state, and the functions of buttons 19, 20, 21, 22, 23, and 24 are blocked and do not work. The electrode contact polarity selection switch (10, 11, 12, 13, 14, 15, 16, 17) is a single-pole three-throw switch, and the three positions of the switch correspond to "-", "0" and "+" respectively. The position of means respectively setting the polarity of the electrode contact corresponding to the switch as negative, empty and positive. The channel selection switch 8 is a single-pole double-throw switch, which can be dialed to "1" or "2", indicating that the current parameter adjustment operation is valid for the currently set channel (1 or 2). The stimulation mode selection switch 9 is a single-pole double-throw switch, which can be turned to "V" or "I", indicating that the current output pulse is a constant voltage mode or a constant current mode. The impedance test button 18 is used to test the electrode load impedance of channel 1 and channel 2. Buttons 19, 20, 21, 22, 23, and 24 are used to adjust the output electric pulse parameters. The function of button 19 is to increase the pulse amplitude, the function of button 20 is to decrease the pulse amplitude, the function of button 21 is to increase the pulse frequency, and the function of button 22 is To reduce the pulse frequency, the function of the button 23 is to increase the pulse width, and the function of the button 24 is to reduce the pulse width. The display screen 7 is used to display the current working state of the test stimulator, that is, the amplitude, frequency and pulse width of the current output electric pulse, the electrode impedance test result, and the battery low voltage alarm information. The dotted line part under the battery compartment cover 30 is the battery placement position, and the test stimulator is powered by two AA common dry batteries. The circuit board 25 placed inside the shell is fixed inside the shell with four screws. The housing is provided with four screw locations 26, 27, 28, 29 for assembly. There is a surface film 32 on the top of the test stimulator shell, and pulse output interfaces 34, 35, and the interface adopts an earphone interface with a buckle slot 36.

Figure 4 shows a specific information display on the display screen. After the power switch is turned on, the display screen is shown in Figure 4(a). The displayed information includes the parameters of the current output electrical pulses of channel 1 and channel 2, including pulse amplitude, Frequency, pulse width, and parameter unit, when the stimulation mode is set in constant voltage mode, the pulse amplitude unit is displayed as "V", as shown in Figure 4(a), when the stimulation mode is set in constant current mode, the pulse amplitude unit is displayed as "mA", as shown in Figure 4(b). The meanings of the icons shown in Figure 4(a)-(b) are: - pulse amplitude; - pulse frequency; --Pulse Width. When the impedance test button is pressed, the display will display the words "Testing, please wait...", as shown in Figure 4(c), and the electrode impedance information will be displayed after the measurement result is shown in Figure 4(d). When it is detected that the battery voltage is lower than the set threshold, the display will display "low battery voltage!" to give an alarm. After a few seconds, it will return to the main display screen, and the upper right corner of the display will appear The symbol continues to alert, as shown in Fig. 4(f).

The circuit composition of the test stimulator is shown in Figure 5, mainly including microcontroller 37, power management and self-locking circuit 38, battery voltage sampling circuit 50, pulse output circuit module 40, display screen 49, key input circuit 47, switch circuit 44 and 48 etc. in:

The micro-controller 37 is the control core of the test stimulator circuit, and mainly realizes two functions: one is to control human-computer interaction, respond to buttons and switch inputs, and set the display output; the other is to control the pulse output module 40 to generate electric pulse output.

The test stimulator is powered by two AA ordinary batteries 39, and the power management and self-locking circuit 38 stabilizes the voltage of the battery to 3.3V to supply power to the microcontroller 37, and provides a self-locking function, that is, the locking pulse output remains unchanged, and the micro-controller The device 37 does not respond to parameter adjustment buttons. The battery voltage sampling circuit obtains the divided voltage value of the battery voltage through the voltage of the AD sampling resistor, and obtains the battery voltage value through calculation, and measures it once every hour. A low voltage warning message is issued.

The button input circuit 47 inputs pulse parameter adjustment and electrode impedance test commands to the microcontroller 37 for processing, and the two switches 48 for mode selection and channel selection provide the current selection state to the microcontroller 37 .

The pulse output module 40 is used to generate electric pulse signals in two modes of constant voltage or constant current, mainly composed of DC-DC circuit 41, constant voltage/constant current pulse output circuit 42, charge balance and electrode impedance test circuit 43, electrode contacts Polarity selection circuit 44 and so on. Among them, the DC-DC circuit 41 can both step up and step down, the output voltage range is 0-10V, and the pulse current output capacity is not less than 20mA under a load of 500 ohms: the channel selection circuit 51 is connected to the output of the DC-DC circuit 41, through the micro The controller 37 selects one or two electric energy storage capacitors for charging and pulse output, and sets the output polarity combination of each channel through the electrode contact polarity selection circuit 44; the constant voltage/constant current pulse output circuit 42 can generate constant The pulse output in two modes of current or constant voltage; the charge balance circuit in the charge balance and electrode impedance measurement circuit 43 is used to generate a pulse signal opposite to the stimulation pulse, so as to realize the positive and negative charge balance of the stimulation target and avoid damage target tissue.

Figure 6 is a block diagram of electrode impedance testing. The test stimulator 56 sends a discharge stimulation pulse to the electrode 53. When there is an electrode impedance test command, the electrode impedance test circuit 54 obtains the current information of the pulse output by collecting the voltage of the sampling resistor through the AD, and hands it to the 57 for software processing, and returns the test result 58 Give the test stimulator 56. The test results can be compared with the previous data such as the early electrode impedance measurement value or the pre-estimated value, so as to judge whether the electrode can work normally, whether the positioning is accurate, and whether the stimulation signal can be effectively transmitted, and can be roughly estimated according to the test results Working life of the implanted pulse generator.

The embodiments described above are only one of the more preferred specific implementations of the present invention, and changes and substitutions made by those skilled in the art within the scope of the technical solutions of the present invention shall be included in the protection scope of the present invention.

Claims (7)

1. An in vitro test stimulator for nerve electrical stimulation therapy test evaluation, said test stimulator has a user interface, before implanting the pulse generator, the doctor connects electrodes to the test stimulator pulse output port by test leads, A preliminary test is carried out, which is characterized in that it contains: a pulse parameter setting device, an output control device, a display device, a microcontroller, a pulse output circuit module, a power supply, a power management circuit and an operation mode switching component, wherein: The pulse parameter setting device is used to generate one of the following command signals at a time: amplitude upward adjustment, amplitude downward adjustment, frequency upward adjustment, frequency downward adjustment, pulse width upward adjustment, pulse width downward adjustment, electrode impedance test; The output control device is used to set the power switch state and user operation mode, and is also used to set the polarity combination of each electrode contact under each channel, as well as to select the stimulation mode and the channel that is valid for the current parameter setting; The display device is used to display the current pulse output parameters, electrode impedance test results, and warning information when the power supply is insufficient; Pulse output circuit module, including: voltage modulation circuit, pulse output control circuit, charge balance circuit and electrode impedance test circuit; Microcontroller, which can receive the instruction signal output by the pulse parameter setting device, and can also receive the signal output by the output control device, output instructions and data for display to the display device, and monitor the pulse output The output of the circuit module; in, The test stimulator has a first operation mode suitable for doctor's operation and a second operation mode suitable for patient operation, the operation mode switching part is used to switch the operation mode of the test stimulator, in the first operation In the first mode, the doctor can set the operating parameters of the test stimulator, in the second mode of operation, the patient can only view the display and readings of the display device. 2 . The test stimulator according to claim 1 , wherein the operation mode switching part is a self-locking gear of the power switch gear, and a leather sheath designed outside the casing of the test stimulator. 3 . 3. The test stimulator according to claim 2, characterized in that, the test stimulator is suitable for use outside the body, the pulse parameter setting device includes a control button, the output control device includes a toggle switch, the The power source is battery. 4. test stimulator according to claim 1, is characterized in that, the display content of described display device comprises: the amplitude, frequency, pulse width of the output pulse of described test stimulator and the amplitude, frequency, pulse width of pulse unit, the electrode impedance test results and the electrode impedance and power supply low voltage alarm information under each channel. 5. The test stimulator according to claim 1, wherein the polarity of the electrode contacts is selected from "+", "-" and "0", and the stimulation mode is constant current mode or constant voltage mode . 6. The test stimulator according to claim 1, wherein the pulse output control circuit works in a constant voltage mode or a constant current mode correspondingly according to the stimulation mode set by the output control device, and in the constant In voltage mode, the voltage range output by the pulse output circuit module is 0-10V, and in the constant current mode, the current intensity output by the pulse output circuit module is 0-25mA. 7. The test stimulator according to claim 1, characterized in that, after each pulse electrical signal output by the pulse output circuit module, the charge balance circuit generates a reverse balanced pulse electrical signal; The electrode impedance test circuit can measure the impedance of the electrode connected to the test stimulator; The power management circuit contains: A voltage stabilizing circuit, which stabilizes the output voltage of the power supply at a set value, and supplies power for the microcontroller and the display screen; Self-locking circuit, used to lock the working state of the test stimulator and turn off the button function; The power supply voltage sampling circuit is used to detect the power supply voltage at regular intervals, and if the voltage value is lower than the set threshold value, the microcontroller will issue a low voltage alarm through the display device.