Electrical transcutaneous stimulator

Abstract

The present technical solution relates to an electrical stimulator. The technical result achieved in solving the technical problem of interest is that of allowing effective real-time control of arbitrary-waveform stimulation. An electrical stimulator is based on an arbitrary-waveform current generator and consists of a housing having the following series-connected elements arranged therein: a power supply; a current sensor capable of transmitting a feedback signal to an input of an analog-to-digital converter (ADC) of a microcontroller; an ADC of a microcontroller, which receives at an input thereof an analog feedback signal for conversion to a digital signal for subsequent processing by the microcontroller; a microcontroller capable of adjusting, in real time, the amplitude, frequency and waveform of a transcutaneous stimulation signal according to the received feedback signal, and of transmitting the modified signal to a digital-to-analog converter (DAC); a DAC capable of converting the computed digital signal of the microcontroller to an analog signal for transmission to a current generator; a current generator which receives at an input thereof the signal from the DAC and outputs a corresponding current signal to electrodes for providing transcutaneous electrical stimulation; electrodes capable of passing a signal to the skin of a user to provide transcutaneous stimulation, the output signal from the electrodes being fed to the current sensor as a feedback signal.

Description

[0001] SURFACE ELECTROSTIMULATION FOR SENSORY FEEDBACK BASED ON A DIGITAL TRACKING SYSTEM FIELD OF TECHNOLOGY

[0002] The present technical solution relates to an electrical stimulator based on an arbitrary current generator with adjustment to skin impedance parameters to provide sensory feedback using arbitrary current signals.

[0003] LEVEL OF TECHNOLOGY

[0004] Known from the prior art is patent RU2529471C2 “Method of cutaneous electrical stimulation of the spinal cord”, published on September 27, 2014, patent holder Kosima LLC. This solution describes a method for cutaneous electrical stimulation of the spinal cord, which includes exposure to a sequence of electrical rectangular bipolar stimuli in the form of meanders with a frequency of 5-40 Hz, a duration of 0.5 ms and a carrier frequency of 10 kHz on the area above the thoracic vertebrae T11-T12 of a patient placed "lying on his side", with legs suspended in swing frames, characterized in that an effect is additionally carried out in the area of ​​​​the cervical C4-C5 and lumbar L1-L2 vertebrae, while stimulation is carried out simultaneously in all areas of the spinal cord with a shift in the pulses in the packet of applied stimuli in phase within 0.1 -0.5 ms, while the amplitude is selected within 40-200 mA so that the procedure does not cause pain.

[0005] Patent RU2627359C2, "Device for Non-invasive Electrical Stimulation of the Spinal Cord," published August 7, 2017, owned by Kosima LLC, is known from the prior art. This patent describes a spinal cord electrical stimulator comprising five stimulation channels (1-5) with an electrode system. Each channel includes a series-connected voltage converter, a current generator, and an output signal former and is capable of generating rhythmic modulated bipolar pulses, rhythmic monopolar rectangular pulses, and rhythmic or single unmodulated monopolar rectangular pulses, with a stimulation frequency in the range of 1-99 Hz, a current amplitude from 1 to 300 mA, and a modulation frequency from 4 to 10 kHz.The inputs of each channel are connected to a microcontroller, which is connected to the indication unit, controls and radio module and is configured to start at least one stimulation channel, select the start mode independently for each of the stimulation channels, control for each of the stimulation channels the pulse parameters selected from at least the pulse shape, stimulation frequency with a frequency change step of 1 Hz, modulation frequency with a frequency change step of 1 kHz, current strength with a change step of 1 mA, pulse duration with a change step of 0.1 ms.

[0006] The prior art includes patent RU2642384C1 "Method for regulating a patient's visceral functions by non-invasive stimulation of the spinal cord", published on January 24, 2018, patent holder Kosima LLC.

[0007] This solution describes a method for regulating the visceral functions of a patient by non-invasive stimulation of the spinal cord, characterized by the fact that at least one cathode is placed on the skin of the patient dorsally above the segment of the spinal cord at the level of innervation of the corresponding organ or organs, and two anodes are placed on the skin ventrally symmetrically relative to the vertical axis of the patient's body in the area of ​​the clavicles, ribs, iliac crests or on the folds of the hip joints depending on the functions being regulated; an effect is exerted by a sequence of electrical rectangular pulses through the said electrodes with a pulse amplitude of 10-150 mA, a pulse repetition frequency of 0.2-100 Hz, and a pulse duration of 0.5-1 ms.

[0008] The disadvantages of known solutions in this field of technology are insufficient activity and expression of stimulated movements.

[0009] Furthermore, prior art solutions utilize simple current generators based on transistor amplifiers to deliver stimulation, typically with rectangular biphasic current pulses. Such devices have a number of limitations, particularly their inability to arbitrarily control the stimulation waveform. Regarding the use of indirect monitoring of the amount of charge delivered, such solutions have several drawbacks, including low accuracy and low speed.

[0010] The main difference between the proposed solution and prior art solutions is the ability to stimulate using an arbitrary waveform to provide sensory feedback. The output signal is monitored digitally, generating a low-power signal fed to the amplifier input and subsequently to skin electrodes. The programmability of the waveform allows for the selection of parameters to optimize energy consumption. The use of various current waveforms allows for the generation of a wider range of sensations, many of which are more naturalistic than those experienced with rectangular pulse stimulation.

[0011] ESSENCE OF THE INVENTIONPC17RU2025 / 000022 The technical problem, which the claimed technical solution is aimed at solving, is the creation of an electrical stimulator based on a generator of an arbitrary current shape with adjustment to the parameters of skin impedance to provide sensory feedback using signals of an arbitrary current shape.

[0012] The technical result achieved by solving the above technical problem is the effective control of arbitrary-shaped stimulation in real time.

[0013] In addition, the use of different current shapes allows for the generation of a wider range of experienced sensations, many of which are more naturalistic compared to stimulation with rectangular pulses.

[0014] The stated technical result is achieved through the operation of an electrical stimulator, made on the basis of a generator of an arbitrary current waveform, consisting of a housing, inside the housing are placed series-connected:

[0015] power supply;

[0016] a current sensor configured to transmit a feedback signal to the input of an analog-to-digital converter (ADC) of a microcontroller;

[0017] The ADC of the microcontroller receives an analog feedback signal at its input, which is converted into a digital signal for further processing on the microcontroller;

[0018] a microcontroller capable of adjusting the amplitude, frequency and shape of the transcutaneous stimulation signal depending on the received feedback signal in real time and transmitting the modified signal to a digital-to-analog converter (DAC);

[0019] A DAC capable of converting the calculated digital signal from the microcontroller into an analog signal for transmitting it to the current generator;

[0020] a current generator that receives a signal from a DAC as an input and outputs a corresponding current signal to electrodes for transcutaneous electrical stimulation;

[0021] electrodes configured to transmit a signal to the user's skin to perform transcutaneous stimulation, the output signal from which is fed to the current sensor as a feedback signal.

[0022] DETAILED DESCRIPTION OF THE INVENTION

[0023] The following detailed description of the invention includes numerous implementation details to provide a clear understanding of the present invention. However, one skilled in the art will readily understand how the present invention may be used with or without these implementation details. In other instances, well-known methods, procedures, and components have not been described in detail to avoid obscuring the features of the present invention.

[0024] Furthermore, it will be clear from the foregoing description that the invention is not limited to the embodiment described. Numerous possible modifications, changes, variations, and substitutions, while preserving the spirit and form of the present invention, will be apparent to those skilled in the art.

[0025] The proposed solution is an electrical stimulator based on an arbitrary current generator, consisting of a housing within which the following main functional units are located: a power source, a current sensor configured to transmit a feedback signal to the input of an analog-to-digital converter (ADC) of a microcontroller, the ADC of the microcontroller to the input of which an analog feedback signal is received, converted into a digital signal for its further processing on the microcontroller, a microcontroller that adjusts the amplitude, frequency and shape of the transcutaneous stimulation signal using a mathematical algorithm based on a proportional-integral-differentiative (PID) controller depending on the received feedback signal in real time with a delay of about 2 μs and transmits the modified signal to a digital-to-analog converter (DAC), DAC,which converts the digital signal calculated by the PID controller from the microcontroller into an analog signal for transmission to the current generator. The current generator receives the signal from the DAC as an input and outputs the corresponding current signal to the electrodes for transcutaneous electrical stimulation. These units communicate with each other via a system of signals: a feedback signal, a control signal, and a stimulation signal.

[0026] In addition, the electrical stimulator comprises electrodes connected to the stimulator via wires and configured to transmit a signal to the user's skin to perform transcutaneous stimulation, the output signal from which is fed to the current sensor as a feedback signal.

[0027] Monitoring the stable shape of the output stimulus signal is accomplished using a feedback signal received from a current sensor, such as a resistor connected in series with the load. The feedback signal is fed to the microcontroller's ADC input, where it is converted into digital code. The digitized feedback signal can be used in computing applications. PC17RU2025 / 000022

[0028] Operations for adjusting the control signal using a PID controller. The control signal is generated using a DAC onboard the microcontroller. This signal defines the desired waveform of the stimulation signal. The output current profile can be changed in real time by changing the signal parameters in the controller's memory or offline by a one-time reprogramming. The control signal value is fed to the input of a cascade based on a high-voltage operational amplifier connected as a non-inverting amplifier. This amplifier amplifies the signal in voltage and applies it to the electrodes as a stimulation signal. The load current is then measured to calculate the feedback signal, and the entire cycle is repeated.

[0029] In these application materials, a preferred disclosure of the implementation of the claimed technical solution was presented, which should not be used as limiting other particular embodiments of its implementation, which do not go beyond the scope of the requested scope of legal protection and are obvious to specialists in the relevant field of technology.

Claims

Formula 1. An electrical stimulator, based on a generator of arbitrary current, consisting of a housing, inside the housing are placed series-connected: power supply; a current sensor configured to transmit a feedback signal to the input of an analog-to-digital converter (ADC) of a microcontroller; ADC of the microcontroller, to the input of which an analog feedback signal is received, converted into a digital signal for further processing on the microcontroller; a microcontroller capable of adjusting the amplitude, frequency and shape of the transcutaneous stimulation signal depending on the received feedback signal in real time and transmitting the modified signal to a digital-to-analog converter (DAC); A DAC capable of converting the calculated digital signal from the microcontroller into an analog signal for transmitting it to the current generator; a current generator that receives a signal from a DAC as an input and outputs a corresponding current signal to electrodes for transcutaneous electrical stimulation; electrodes configured to transmit a signal to the user's skin to perform transcutaneous stimulation, the output signal from which is fed to the current sensor as a feedback signal.