Electronic circuit for muscle stimulation, and control method

Abstract

The invention relates to an electronic circuit for muscle stimulation, comprising multiple electrode elements on a textile carrier material designed to be worn on the human body, and to a control method. The textile carrier material is designed such that, when worn on the human body, the contact surfaces of multiple electrode elements are in touching contact with different sections of the skin of the human body in regions of a predetermined same muscle. During muscle stimulation, a sequence of electrical pulses is supplied to the muscle via external electrodes with touching skin contact, and motor units of the muscle are thereby activated. Beforehand, for the pulse sequence, relevant parameters such as pulse frequency and / or pulse duration, pulse profile, pulse pauses etc. are set or a selection is made from among readily available pulse sequence programs, and the pulse strength can also be adjusted during the treatment. The supplied pulse sequence contains first pulse pauses with a duration of at least 5 ms between at least two, preferably at least three, successive pulses and second pulse pauses of between 3 μs and 100 μs between at least 4 and at most 400 successive pulses.

Description

[0001] Electronic circuit for muscle stimulation and control methods

[0002] INTRODUCTION AND STATE OF THE ART

[0003] The invention relates to an electronic circuit for muscle stimulation, or neuromuscular stimulation, and an associated control method.

[0004] In neuromuscular stimulation, electrical signals are applied externally to the skin, for example via adhesive electrodes, in order to activate muscles, or more precisely, their motor units.

[0005] Most commonly used stimulators employ bipolar pulses. With bipolar pulses, the current direction is reversed to maintain charge neutrality (ion neutrality) within the body. These bipolar pulses have durations between 20 and 500 seconds. Current intensities vary from less than a few milliamps in transcutaneous electrical nerve stimulation (TENS, for pain therapy and improved circulation), to 10 to 50 mA in electrical muscle stimulation (EMS, for muscle control and development), and up to 50 to 200 mA in cases of severe paresis or plegia, where the patient lacks receptor feedback for pain. These pulses are applied at various frequencies, typically between 1 Hz and 120 Hz. In this application, as is customary, "frequency" refers to the inverse of the pulse interval (in seconds), meaning that two pulses can share the same frequency.Other definitions, such as the number of pulses per second, are also used in practice.

[0006] The pulses are applied to the skin's surface via electrodes. The most commonly used electrodes are hydrogel, gel, or adhesive electrodes with an extra gel-like layer to improve contact with the skin and reduce impedance. Alternatively, electrodes without such a layer, known as dry electrodes, are available.

[0007] Dry electrodes can be applied to flat substrates, such as textiles, for example, on the inside of garments worn next to the skin, but in practice they are often problematic. Compared to other electrodes, dry electrodes exhibit higher impedance values ​​due to less effective skin contact. These higher impedance values ​​are more susceptible to the effects of situational factors such as humidity, perspiration, and electrode pressure, which can be influenced by fluctuations in climate, the patient's physical condition, and posture. Excessively high and fluctuating impedances pose a significant problem for muscle stimulation. Therefore, gel-applied and / or adhesive electrodes are preferred for muscle stimulation in practice.

[0008] Muscle stimulation is typically performed in treatments lasting 20-60 minutes. Often, medically relevant parameters, such as pulse width and frequency, are set by medical personnel before the treatment begins. The current intensity / amplitude can then be adjusted by the user / patient in real time before and during the treatment. Alternatively, there are devices with a pre-defined selection of manufacturer-prepared program sets. These programs feature fixed variations in amplitude, frequency, or pulse duration, associated with different medical indications (e.g., body parts and treatment reason). Most of these programs are designed to contract a muscle for periods ranging from 0.2 seconds to several seconds and then relax it again for a certain duration.From the user's perspective, the most important parameter is always the current; many devices do not offer the user any settings for frequency and pulse width.

[0009] Such systems have been known for a long time. For example, patent US6445955B1 describes a system for transcutaneous muscle stimulation with selectable monopolar or bipolar waveforms. The system includes electrodes, an electronics module, a power unit, and a user interface, and it provides similar parameterization options for amplitude, frequency, and pulse duration as are common today.

[0010] The duration of muscle stimulation treatments is limited because they lose their effect or are perceived as unpleasant after approximately 20-60 minutes. Therefore, muscle stimulation treatments, for example, after injury-related muscle atrophy, must be repeated over a longer period. A particular disadvantage is the high level of care required from medical personnel, especially when parameter settings are individually tailored to the patient and the specific situation. Furthermore, attempts to increase the effect of individual muscle stimulation treatments by applying higher current and voltage levels are perceived as unpleasant.

[0011] In such cases, both individual pulses of painfully high intensity and the cumulative energy input locally into the muscle during a 20-60 minute stimulation treatment can cause unpleasant sensations. Therefore, established systems feature a user interface that can be operated by the patient and / or caregiver, allowing the applied current and voltage values ​​to be adjusted in real time. These settings are reconfigured for each stimulation treatment.

[0012] Manufacturer-prepared program sets, on the other hand, have the disadvantage that no patient-specific settings are provided; rather, preset variations of amplitude, frequency, or pulse duration serve to cover the broadest possible range of applications within the scope of generally specified medical indications. An object of the present invention is to enable muscle stimulation treatments in home applications, i.e., without the need for supervision by medical personnel, whereby electrodes can be applied to a patient at more reproducible positions on their body, and electrical signals with a reproducible biological stimulation effect can be delivered to the patient via these electrodes.Another object of the present invention is to increase the effect of muscle stimulation treatments without increased care required by medical professionals and without applying higher current and voltage values.

[0013] This problem is solved by the electronic circuit for muscle stimulation according to claim 1 and the control method according to claim 13. The dependent claims relate to advantageous embodiments and further developments.

[0014] In a preferred application, the electronic circuit is used to reduce atrophy and to stimulate the motor units of a muscle as evenly as possible.

[0015] Further features and advantages will become apparent from the following description and the accompanying figures. These, as well as the patent claims, disclose features of the invention in specific embodiments, examples of embodiments, and combinations. However, the disclosed features can also be considered individually and combined into further combinations or sub-combinations to adapt the invention, as defined in the claims, to specific needs or areas of application.

[0016] BRIEF DESCRIPTION OF THE FIGURES

[0017] Figure 1 is an example system diagram. Figure 2 shows an example and schematically a connection with a support system.

[0018] Figure 3A shows a typical placement of stimulation electrodes on the vastus medialis.

[0019] Figure 3B shows a distribution of motor units in the vastus medialis.

[0020] Figure 3C schematically shows an external view of an exemplary textile carrier for an electronic circuit to be worn on the leg.

[0021] Figure 3D schematically shows a view through the textile carrier with stimulation electrodes and associated electrical connections.

[0022] Figure 4A shows an illustrative example of a bipolar pulse.

[0023] Figure 4B shows an illustrative example of a decomposition of a bipolar signal into 16 micropulses.

[0024] Figure 5 illustrates micropulse groups using examples on different timescales.

[0025] Figure 6A shows exemplary measured impedance spectra for dry electrodes with skin contact and, in comparison, for hydrogel electrodes with skin contact.

[0026] Figure 6B shows Figure 6A with exemplary guidelines.

[0027] Figure 7 shows a block diagram for an exemplary embodiment of the electronic circuit.

[0028] Figure 8 shows an example of stochastically distributed bipolar pulses on a millisecond scale. Figure 9A shows an example of a stochastic distribution of the pulses as a histogram.

[0029] Figure 9B shows an illustrative example of a stochastic distribution of pulses as a histogram with frequency restriction.

[0030] Figure 10 shows a block diagram of another illustrative example of an electronics device.

[0031] Figure 11A schematically shows four stimulation electrodes in an exemplary arrangement for the vastus medialis.

[0032] Figure 11B shows, by way of example, two different current paths with different selections of electrode elements from the four stimulation electrodes in the exemplary arrangement for the vastus medialis.

[0033] Figure 12A shows an illustrative example of an electronic circuit on a textile substrate.

[0034] Figure 12B shows an illustrative example of an electronic circuit on a textile substrate with an additional sensor element.

[0035] DESCRIPTION OF THE INVENTION

[0036] The electronic circuit according to the invention for muscle stimulation is a device for applying electrical current pulses to a human body via electrodes in contact with the skin.

[0037] Figure 1 shows an exemplary and highly simplified system diagram with the main components: control unit 1000, electrode elements 2000, and contact surfaces 4100 on the human body 4000, as well as an external user interface 5000. For the sake of simplicity, a user interface with a power-off function, which is part of the circuit, is not shown in this example. In this document, "user" (hereinafter also "patient") refers to a person whose body is electrically contacted via sections of skin and who receives a sequence of electrical pulses via the electrode elements. In contrast, "medical caregiver" (hereinafter also "caregiver") refers to a person different from the "user" who can adjust settings regarding the pulse sequence to be delivered without receiving it on their own body. Both persons can operate the user interface.

[0038] DRY ELECTRODES ON A CARRIER TO BE WORN ON THE BODY:

[0039] The electronic circuit according to the invention is designed for comfortable and practical everyday use on the human body and for frequently repeated muscle stimulation treatments. For this purpose, the electrode elements are designed as dry electrodes and provided with electrically conductive layers to establish electrical contact between the electrode elements and the human body at contact surfaces without the use of liquid, gel-like, or adhesive contact agents.According to the invention, the electrode elements are permanently integrated onto a textile carrier material designed for wear on the human body. This carrier material is designed to reproducibly and reusably position and hold the electrically conductive layers of the dry electrodes in the necessary position for muscle stimulation at the contact surfaces with the human body, preferably such that the contact surfaces of several electrode elements are in contact with different sections of the skin of the human body in areas of a predetermined muscle to be stimulated. For this purpose, the textile carrier material can, for example, be designed as a garment that fits snugly against the body.The stationary integration of the electrode elements on the substrate can be achieved using materials and processes from printed electronics. For example, the electrically conductive layers at skin contact surfaces can be formed with electrically conductive inks and applied to the substrate by screen printing followed by drying and curing of the inks. Preferably, the electrode elements on the substrate comprise several layers, including at least one electrically insulating layer between the electrically conductive layer at skin contact surfaces and the substrate. The application of the layers can be accomplished by transfer printing or direct printing onto the substrate.

[0040] Figure 2 shows an exemplary and schematic connection with a carrier system. In addition to the electrode elements 2000 being firmly connected to the textile carrier material 6000, electrical connections 2100 for contacting the electrode elements and a receiving device 6500 for mechanically and electrically releasable mounting of the control unit 1000 are also shown. The releasable mechanical connection can be made, for example (not shown in the figure), via a magnetic, clip, or bayonet connection between the receiving device and a housing section of the control unit. The releasable electrical connection can be made, for example, via pressure or plug connections between contact elements 1010 of the control unit and contact elements 6510 of the receiving device, which in turn are connected to the electrical connections 2100 for contacting the electrode elements 2000.The detachable design of the mounting of the control unit 1000 is preferred in order to be able to separate it from the textile carrier 6000, for example when several textile carriers are used alternately or when one (or more) of the textile carriers are washed.

[0041] The system further comprises a user interface 5100, connected to the control unit 1000 and worn on the body during use of the circuit. This interface includes a switch-off function, preferably also a switch-on function and pulse height regulation function. Separately from the control unit 1000 and the user interface 6000, an interface 5200 for external operator input and / or bidirectional data communication may also be provided.

[0042] The textile carrier material is designed so that, when worn on the human body, the contact surfaces of several electrode elements are in contact with different sections of the skin in areas of a predetermined muscle to be stimulated. The electrode elements are arranged on the textile carrier material such that the current paths of the stimulation pulses preferably run entirely or largely through the muscle to be stimulated. This requires several, i.e., at least two, electrode elements, which can be operated with different polarities when stimulation pulses are applied.Depending on the size and position of the muscle to be stimulated, electrodes can be placed on the skin in areas directly above the muscle and / or in adjacent areas. Electrode placement can be chosen so that motor units of only one muscle are activated, or alternatively, so that motor units of several adjacent muscles are stimulated collectively. If different current pathways through the muscle are to be created in different directions, at least two of the three or more electrode elements can be arranged differently in a first direction and two of the three or more electrode elements in a second direction, for example, in the lateral-medial and distal-proximal directions. In any case, the first and second directions are preferably different from each other and cover an area, in the simplest version with three electrode elements, a triangle.

[0043] The contact area of ​​the electrical circuit is the interface area between the electrical circuit and the skin and has a minimum size of 1 mm. 2 per electrode. If the textile carrier material is a close-fitting garment, the contact area can be up to the size of the anatomical structure, such as the leg. Preferably, a contact area for muscle stimulation has a size of between 600 mm². 2 and 10000mm 2 for individual stimulation electrodes and 50mm 2 and 900 mm 2 per electrode for electrode arrays.

[0044] To account for the fact that different users / patients have different body types and that stimulation electrodes need to be positioned accordingly, it is possible to have electrodes in many different positions within textile carrier materials. From these, a selection of electrodes for muscle stimulation treatment can be made that is individually adapted to the user's / patient's specific body type. In such a case, electrode elements can also be placed wholly or partially on other muscles that are not being stimulated.

[0045] Figure 3A schematically shows a simple electrode layout with two stimulation electrodes 2000 for stimulating a human body 4000 using the vastus medialis as an example.

[0046] Figure 3B shows, also schematically, the shape of the vastus medialis 4200, as well as the distribution of motor units 4300 within the vastus medialis. It can be seen that the distribution of motor units is not homogeneous throughout the muscle. This is generally true for all muscles. Motor units are not preferentially located in the outer regions of the muscle. For the vastus medialis, the distribution is significantly more distal. Motor units are primarily responsible for the final electrical step of muscle activation and are stimulated by external muscle stimulation.

[0047] Figure 3C schematically shows an external view of a textile carrier material 6000, which in the present example is designed as a leg sleeve, i.e., as a textile leg covering that encloses the leg in a tubular fashion, lying close to the body 4000. The receiving device 6500 for the detachable receiving of the control unit 1000 is located on its outer surface, preferably in the lateral region of the thigh, and particularly preferably laterally and centrally on its outer side.

[0048] Figure 3D shows a corresponding schematic view through the textile carrier 6000, with the elements visible in the external view in Figure 3A shown as dashed lines. The view shows the stimulation electrodes 2000 in the arrangement shown in Figure 3A, as well as associated electrical connections 2100, each attached to the inside, i.e., the side facing the human body, of the textile carrier.

[0049] MICROPULSE DECLUTTERING:

[0050] The electrode elements 2000 serve for the electrical contact of a section of the skin of the human body and for this purpose have an electrically conductive layer on their contact surface 4100 in order to apply a sequence of electrical pulses via this surface. Preferably, the electrical pulses are bipolar to ensure charge neutrality and to minimize electrochemical reactions.

[0051] Figure 4A shows an example of a bipolar pulse 3500. In this example, the pulse is symmetrical and therefore has the same pulse profile with the same pulse widths and amplitudes for positive and negative currents. The depicted bipolar pulse has a pulse length of 400 ps and an amplitude of 30 mA for both current directions. Positive and negative currents can also differ for bipolar pulses, as long as overall charge neutrality prevails.

[0052] According to one aspect of the invention, current pulses are decomposed into micropulses; that is, the controller is configured to supply the multiple electrode elements with a sequence of charge-neutral current pulses, preferably averaging at least 1 ms, wherein a pulse sequence has first pulse pauses of at least 5 ms in duration between at least two, preferably at least three, successive pulses, as well as second pulse pauses ("micropauses") of between 3 ps and 1 OOps between at least 4 and at most 400 successive pulses ("micropulses"). Successive pulses that are interrupted by micropauses but not by a first pulse pause (greater than 5 ms) are referred to as micropulse groups.

[0053] Figure 4B shows an example of a micropulse group 3700 with a pulse duration of 350. In this example, the micropulse group contains eight positive micropulses and eight negative micropulses. After each micropulse 3400, there is a micropause 3410. Each micropulse has a micropulse duration of 3420. The micropulse duration and the micropause together constitute the total micropulse duration. The envelope curve of the micropulse group is shown with a dashed line and labeled "Envelope". The area under the integral of micropulses with the same sign, or intuitively, their sum, is shown with a dotted line and labeled "Scale Envelope".

[0054] According to this aspect of the invention, "compact" pulses are divided into n micropulses by micropauses, the division preferably being integer. The pulse sequences used for muscle stimulation therefore contain micropulse groups instead of conventionally used "compact" pulses, or contain combinations of micropulse groups and known pulses. Micropauses are chosen to be so short that individual micropulses of a micropulse group, after passing through skin and other tissue layers, are no longer perceived in time at the location of the motor units, but physiologically only as part of a longer pulse. As a result, a charge-neutral micropulse group, averaged over time, is perceived like a bipolar pulse and, when used for muscle stimulation, has comparable physiological effects to a compact pulse, provided the interruptions caused by the micropauses are appropriately compensated by adjusting the amplitude and duration.Preferably, the pulses to be supplied form a group of micropulses with a micropulse duration of at most 80 ps, ​​preferably in the range of 1 ps to 20 ps, ​​and with micropauses between successive micropulses of at most 80 ps. Furthermore, preferably, the micropauses are shorter than the micropulse duration. Due to the micropauses between the micropulses, less charge is transported within a micropulse group than with compact pulses of the same pulse duration and amplitude. This effect can be compensated for by longer pulse durations and / or higher amplitudes.

[0055] According to the invention, micropulse groups of the type described above are used for muscle stimulation and supplied to the electrode elements. They can be described with properties / parameters and adjusted via the adjustment device that they share with properties / parameters of "compact" pulses, i.e., pulses not interrupted by micropauses, as known in the prior art for use in muscle stimulation. Thus, micropulse groups have a pulse width / pulse duration determined by the entire micropulse group and a pulse interval to other micropulse groups or compact pulses, which is represented by a frequency as the pulse frequency and can be adjusted via the adjustment device.These settings for micropulse groups, as well as settings for micropulse groups regarding amplitudes, pulse profiles and maximum pulse heights, can be clearly viewed as settings for envelopes or scaled envelopes and understood and set by the user or caregiver in this sense.

[0056] "Setting a pulse sequence to be supplied to the electrode elements by the controller with respect to at least one parameter from the group consisting of pulse frequency, pulse duration, pulse profile, pulse pauses, and maximum pulse amplitude" is to be understood in this sense, in the language of this document, also for micropulse groups, for example, in the case of setting the parameter "pulse duration," the next time interval between two initial pulse pauses is to be set; in the case of setting the parameter "pulse pauses," the duration of initial pulse pauses is to be set; and in the case of setting the parameter "pulse frequency," the inverse of the duration of initial pulse pauses is to be set. Furthermore, such "setting" is also to be understood as making a selection from among pulse sequence programs that differ from each other in at least one of these parameters.

[0057] Figure 5 illustrates micropulse groups using examples on different time scales. For understanding the diagram, it is important to note that the time axis is not shown continuously because a continuous representation would make it impossible to resolve the orders of magnitude in a single graph. In the example shown, the amplitude is kept constant at ±30 mA for simplicity; in practice, it can be set and changed by the user or specialist via the user interface. 3210 shows a pulse pause, which is typically between 5 ms and 1000 ms for muscle stimulation. 3220 shows a pulse width, which is typically between 20 ps and 500 ps for muscle stimulation. Reference symbol 3410 shows a micropause. This is generally less than 80 ps. The figure shows two micropulse groups 3701 and 3702 with different pulse durations, and—shown with dashed lines—a bipolar pulse 3500.The bipolar pulse 3500 has neither micropauses nor micropulses; its profile corresponds to the envelope of the micropulse group 3701.

[0058] In Figures 4B and 5, the micropulses are represented as rectangles. In practice, this can be deviated from; micropulse shapes with continuously rising edges and / or non-constant amplitudes are also possible.

[0059] IMPEDANCE REDUCTION:

[0060] For the inventive circuit with dry electrodes on a textile carrier material to be worn on the human body, the use of micropulse groups has the advantage that, compared to compact pulses, they penetrate the uppermost layers of skin into human tissue more easily, thereby reducing the impedance of the contact and thus the required electrical voltages. This counteracts the problem of high impedances in dry electrodes mentioned in the introduction.

[0061] To illustrate this effect, Figure 6A shows exemplary measured impedance spectra of the skin in a double-logarithmic plot for dry electrodes and, for comparison, for hydrogel electrodes. Commercially available AgAgCl adhesive electrodes were used as hydrogel electrodes, in which contact is achieved via a hydrogel acting as the electrolyte. For the dry electrodes (without electrolyte and gel), the electrically conductive layers at the skin contact surfaces were formed using electrically conductive inks and produced by screen printing followed by drying and curing of the inks.

[0062] As can be seen from the impedance spectra shown, the impedance decreases with increasing frequency for both electrode types. To illustrate the magnitude of the effect, exemplary guidelines are drawn in Figure 6B on the impedance spectrum of Figure 6A to demonstrate the influence of a tenfold increase in frequency on the impedance. For example, if compact bipolar pulses of frequency 2 kHz are decomposed into shorter pulses (micropulses), thereby increasing the frequency to 20 kHz, the impedance measured for dry electrodes can be reduced from 21 kΩ to 4.5 kΩ. With a value of 4.5 kΩ at micropulses, the impedance of the dry electrode is lower than the impedance of 10 kΩ of the hydrogel electrode without micropulses. This example illustrates that the impedance of a dry electrode can be reduced by micropulse decomposition, i.e.,The use of micropulses instead of compact pulses can reduce impedance values ​​to those comparable with or even below those of a hydrogel electrode, depending on the chosen frequency increase. Impedance spectra, such as those shown in Figures 6a and 6B, can vary significantly between individuals and different body parts of the same person. These differences depend not only on electrode type but also on other contact conditions such as humidity, the user's / patient's daily condition / perspiration, and the pressure of the electrodes against the skin. However, all impedance spectra share the characteristic that the impedance decreases with increasing frequency up to a frequency of approximately 1 MHz and hardly decreases at even higher frequencies.

[0063] Therefore, a micropulse mapping can be used in a wide parameter range commonly used for muscle stimulation and makes it possible to reduce or avoid adversely high impedance values ​​of dry electrodes depending on the selected frequency increase.

[0064] Impedance reduction through the use of micropulses offers a further advantage for wearable circuits with dry electrodes in direct skin contact: lower electrical power is required for muscle stimulation. For wearable circuits with mobile energy storage (battery), this allows for longer operating times and / or smaller size requirements.

[0065] POWER CONTROL:

[0066] As previously explained, a charge-neutral micropulse group is perceived like a bipolar pulse and, when used for muscle stimulation, has comparable physiological effects to a compact pulse, provided that the micropause-related interruptions are appropriately compensated by adjusting the amplitude and duration. The most important parameter for the physiological effect of the charge-neutral micropulse group is the cumulative current pulse delivered in each direction and its amplitude. In state-of-the-art muscle stimulation, pulse amplitude control is usually voltage-controlled. At the start of treatment, after placing the electrodes in skin contact with the body, the caregiver or user sets one or more pulse parameters (usually amplitude, optionally pulse duration and / or frequency, optionally also with program-controlled temporal variation), typically with initial manual adjustment of pulse parameters.From this initial setting, a target value for the voltage of the pulse amplitudes is determined or specified and used as the control target value in the continuation of the treatment. At the same time, a maximum value for the voltage, which must not be exceeded for safety reasons, can be specified. Such a parameter setting at the beginning of each treatment takes into account that the impedance of the stimulation electrodes in skin contact with the user depends on the situational physical contact between the electrodes and the body and can change from one treatment to the next.

[0067] A current-controlled pulse control is also known in the art, but less frequently used. In this method, a current value is specified for the pulses, and the voltage of the pulses is varied with respect to their amplitude and / or pulse profile until the specified current is reached. Because current-controlled amplitudes require higher voltages with increasing impedances, such circuits must be designed, in addition to current control, to ensure that a predetermined maximum value for voltage or impedance is not exceeded.

[0068] In conjunction with dry electrodes and micropulses, current-controlled pulse control has specific advantages and is therefore used in the circuit according to the invention.

[0069] Unlike gelled or glued electrodes, dry electrodes on textile carriers worn on the body can experience impedance fluctuations during treatment, for example, due to changes in electrode skin contact caused by the user's body movements. With current-controlled pulse trains, such impedance fluctuations are compensated for within the predetermined maximum values ​​for voltage or impedance in the current amplitudes of the pulse trains.

[0070] Furthermore, unlike voltage-controlled pulse sequences, parameter settings at the beginning of each stimulation treatment are unnecessary. This is because current control of the stimulation pulses allows for the compensation of situational or daily-dependent impedance differences between treatments—within the predetermined maximum values ​​for voltage or impedance—similar to impedance fluctuations during a course of treatment. Therefore, instead of setting parameters at the beginning of each stimulation treatment, previously used or pre-defined parameter settings (e.g., by a medical professional) can be employed. Consequently, current control enables reproducible biological stimulation effects even with dry electrodes on textile carriers worn on the body, particularly in home use without the need for medical supervision.

[0071] In micropulses, current-controlled pulse regulation offers the advantage of increased physiological effectiveness compared to voltage-controlled pulse regulation. In simplified terms, muscle activation is based on a sequence of physiological processes. Following an electrical stimulus and exceeding the activation potential of a muscle cell, its cell wall temporarily opens to allow ions from a reservoir outside the cell to pass into the cell. Inside the cell, these ions trigger further reactions, which, in summary, convert chemically stored energy into mechanical energy, resulting in "muscle work" such as muscle contraction. The activating electrical pulse spreads from cell to cell, preferentially along muscle fibers. As the pulse subsides, the ions are transported back to the reservoir outside the cell.

[0072] The inventor hypothesizes that increased ion mobility and subsequent chemical reactions in muscle tissue lead to impedance fluctuations during muscle activation by a stimulation pulse. Such physiologically induced impedance fluctuations can result in fluctuating current amplitudes and physiologically ineffective energy dissipation with voltage-controlled micropulses, which can be avoided with current-controlled micropulse generation.

[0073] According to the invention, dry electrodes on textile carriers to be worn on the body, micropulse fragmentation and current control work together to mutual advantage.

[0074] ELEMENTS OF THE CIRCUIT:

[0075] A specially designed control circuit generates the pulses. This circuit contains at least one cathode and at least one anode as electrodes. Both the anode and cathode can carry pulse signals, or one of the electrodes can be connected to ground. Preferably, current and voltage limiting circuits protect the electrodes from excessively high voltage pulses and current pulses. Furthermore, the electronic circuit preferably includes a mechanism to prevent direct current, for example, a high-pass filter.

[0076] The electronic circuit is equipped with a user interface that allows a user or medical professional to switch the delivery of electrical pulses on and off in real time, and preferably also to control the pulse intensity. The switch-off function of the user interface serves as an "emergency stop" switch and allows for user-guided limitation of the treatment duration with electrical pulses. The switch-on function of the user interface allows the user to initiate the treatment themselves, and the pulse intensity control allows for real-time adjustment of the treatment intensity. This is advantageous, for example, when the most intensive treatment possible is desired, while allowing the user to set the limits to avoid potentially painful overload of the stimulated muscle themselves, in real time.

[0077] Other parameters of the pulse sequence relevant for muscle stimulation can be pulse rate, pulse duration, pulse profile, pulse pauses, and / or maximum pulse amplitude, whereby these parameters are used in the same way for "compact" pulses and envelopes or scaled envelopes of micropulse groups according to the invention. The adjustment device serves to customize at least one of these parameters to the user / patient and the specific situation. In practice, pulse rate and / or pulse duration are particularly frequently adjusted, as is also the case in a preferred embodiment of the present invention.

[0078] The user interface and settings can be implemented together or separately. A fully integrated implementation grants full access to all functions of both the user interface and settings, without differentiating between users and administrators. In contrast, a separate implementation allows for different access rights to the functions of the user interface and settings for users and administrators. A separate implementation can be achieved with separate hardware and / or shared hardware with differently authorized user access.

[0079] Combined implementations are also possible. For example, a combined implementation of a user interface and setting device with a more complex user interface can be supplemented by a simple and robust user interface worn on the user's body, for example in the form of a simple control knob with an on / off click at the bottom stop.Such combinations are also advantageous with a full joint implementation of the user interface and setting device, and regardless of potentially different access options for users and caregivers, since more complex settings – for example, multi-parameter settings – are made via the setting device before the start of treatment and are intended to remain unchanged during the treatment (administration of the pulse sequence), whereas simpler functions of the user interface, at least its shutdown function as an “emergency off” switch, are available in real time during the treatment as intended.

[0080] Overall, the invention can be implemented in various configurations. The electrode elements are always in an electrically conductive connection with the control unit for supplying the current pulses; however, the user interface and setting device can be connected to the control unit via wired and / or wireless connection and can be implemented separately or together.

[0081] In one embodiment of the circuit according to the invention, the functionality of the user interface is limited to a wired shutdown function; further functions of the user interface and / or setting device are provided in one or more external devices, for example as an application on a computer in a doctor's or physiotherapist's practice or on a user's / patient's smartphone.

[0082] In general, in the circuit according to the invention, the reception of operator inputs relating to operations and settings can be carried out via an operator interface device belonging to the circuit and / or via a data receiving device designed as an input interface for externally made operator inputs. Figure 7 shows a block diagram for an exemplary embodiment of the electronic circuit with a controller 1000 and adjacent modules, including electrode elements 2000 and a mobile power supply 1100, for example in the form of a battery, which supplies the energy for all units of the electronic circuit. The controller 1000 includes a central control unit 1300, for example a microcontroller. A DC-DC converter 1200 transforms the voltage of the mobile power source 1100 to the voltages required for muscle stimulation. Preferably, the DC-DC converters generate positive and negative voltages.Alternatively, a unit that reverses the current direction, such as an F-bridge, can be used. The DC-DC converters generate the maximum voltage and can therefore serve as a safety feature because they limit the voltage. For example, the voltage can be limited to 30V. However, for functional stimulation, voltages in the range of 0-120V can also be used; in users / patients with plegia or paresis, even higher voltages can be used within a regulatory framework. Preferably, the current-controlled signal is controlled by lower currents and voltages.

[0083] The functional part of the electronic circuit, which handles direct signal control, is designated as the signal generation unit 1600. Preferably, control is achieved via a voltage. For example, this can be a digital-to-analog converter that transforms an input signal, such as the desired pulse parameters set via the user interface and adjustment mechanism, into an analog output signal. The analog output signal can already correspond to the "end signal" of the electrostimulation pulses, or it can preferably be further modified and / or amplified by an electronic unit. In this case, the signal is designated as the control signal 3100.

[0084] In the exemplary embodiment shown, the control signal 3100 is converted into an electrical stimulation pulse 3200 with the desired parameter by a voltage-current amplifier 1400. This current-voltage amplifier 1400 has a very high output impedance, which is higher than the impedance of the skin in the frequency range used. In general, the impedance should be greater than 1000 ohms, ideally in the gigaohm range.

[0085] Among the adjacent modules shown in Figure 7 is a user interface 5100 with a switch-off function, preferably also with a switch-on function and pulse height control function, and separately from this an adjustment device, in this case formed by a communication device 1900 such as a Bluetooth radio, which is designed for wireless communication and as an input interface for externally made operator inputs. In the example shown, a mobile terminal 5200, on which a corresponding application is implemented, serves as the input device for externally made operator inputs. Via external input, a support specialist can also remotely, i.e., without being on-site at the user's location, adjust parameters or programs.

[0086] If the communication device 1900 is configured for bidirectional communication, the application can be used to input settings for pulses and variations, as well as to output and visualize data, such as data on the circuit's usage history or sensor data, for example, on measured muscle states. Furthermore, this application can also communicate with other applications or data management systems. For example, a medical professional can view, comment on, save, or modify data and pulse settings. In an advantageous embodiment, the use of the electronic circuit is recorded and stored. Data on muscle states can also be stored. This storage can occur within the circuit according to the invention in a memory connected to the controller or via the application in an external memory.If such stored data is available, a suitable program with the respective parameters can be created through an anamnesis; the anamnesis can be carried out automatically.

[0087] ADVANTAGEOUS FURTHER EDUCATION:

[0088] Variation of micropulse decomposition

[0089] In a particularly advantageous initial development step, the setting device allows the user to configure whether, and optionally how many, initial pulse pauses in the pulse sequence follow each other immediately; that is, whether and how often compact pulses, uninterrupted by micropauses, occur consecutively. Furthermore, it is advantageous if the setting device allows the user to change the duration of secondary pulse pauses and / or their relative frequency compared to initial pulse pauses. This can be achieved, for example, by entering a number of micropulses into which the bipolar pulses are divided.

[0090] In a further advantageous embodiment, the micropulses and the number of micropulses per micropulse group are automatically varied, while the frequency relevant for muscle stimulation, i.e., the periodicity of micropulse groups (and compact pulses), remains unchanged. For this purpose, the circuit according to the invention generates, for example, a pulse sequence in which several first pulse pauses have the same duration and the same time interval to the next first pulse pause. In the micropulse groups between successive first pulse pauses, the micropauses each have the same duration and the same time interval; however, the pulse sequence contains micropulse groups with a different number of micropauses. It is further advantageous if the degree and configuration of such automatic variation can be set via the adjustment device.With automatically varying micropulses and an automatically varying number of micropulses or micropauses per micropulse group, the frequency of the micropulses and thus the impedance also vary automatically. This means that when such a pulse sequence is applied, the ratio between voltage and current, or, in the case of current control, the voltage itself, varies. Due to the aforementioned advantages of low impedance, a beneficial setting for decomposing pulses into micropulse groups, e.g., the number of pulses per micropulse group, can be established and subsequently used. This procedure can be performed, for example, at the beginning of a muscle stimulation treatment and optionally repeated periodically and / or when contact problems occur.

[0091] An example of a stimulation treatment with automatic variation of micropulses could be, for instance, an initial pulse sequence with several first pulse pauses of the same duration and the same time interval to the next first pulse pause, between successive such first pulse pauses groups of several second pulse pauses of the same duration and the same time interval to the next second pulse pause, as well as several such groups of second pulse pauses with different numbers of associated second pulse pauses.Subsequently, a second pulse sequence is applied, in which the duration of second pulse pauses and / or the time interval to the next second pulse pause and / or their relative frequency in relation to first pulse pauses is determined depending on a respective voltage or on a respective ratio between voltage and current when several such groups with different numbers of corresponding second pulse pauses in the first pulse sequence are applied.

[0092] Compared to "compact" pulses, i.e., pulses not interrupted by micropauses, micropulses penetrate the uppermost layers of skin more easily due to their higher frequency, and their penetration depth differs from that of compact pulses. Therefore, compact pulses and micropulse groups can activate motor units at varying depths. Furthermore, varying the penetration depth makes it possible to slow down or prevent fatigue of the stimulated muscle, thus achieving more effective and longer-lasting stimulation without increasing the pulse amplitude.

[0093] Variation of stimulation parameters

[0094] In an advantageous second embodiment, the pulse sequence is varied during and over the duration of the pulse sequence application in at least one parameter affected by the setting, preferably by a mean value of the parameter corresponding to the setting pertaining to it, wherein parameters affected by the setting are used in the same way for "compact" pulses and for envelopes or scaled envelopes of micropulse groups according to the invention. This variation serves to slow down or prevent fatigue of the stimulated muscle and thus to enable more effective and longer stimulation without increasing the pulse amplitude.

[0095] The pulse sequence is set by the user or medical professional with respect to at least one well-known and medically relevant parameter from the group of pulse rate, pulse duration, pulse profile, pulse pauses, and maximum pulse amplitude. The difference is that the set parameter(s) are not followed exactly in the delivered pulse sequence, but rather correspond to an average value. This variation allows for an increased stimulation effect with the same parameter selection, without increasing the complexity of operation. As with current technology, users and / or medical professionals can select specific settings based on their existing expertise, depending on the situation.

[0096] A mean value can be the arithmetic mean, median, mode, weighted average, geometric mean, or harmonic mean, and it can also change over several pulse sequences. Preferably, the variation around a mean value involves the pulse interval; more preferably, and additionally or alternatively, it also involves the pulse width.

[0097] The distance from the arithmetic mean of two pulses can be defined as the pulse interval, and the frequency as its inverse unit; alternative definitions can also be used.

[0098] In a particularly preferred application of this advanced training, the parameter to be varied is the pulse frequency or pulse interval, also referred to as pulse pause. Figure 8 shows an example of a sequence of 3200 electrical pulses for muscle stimulation, which is a sequence of bipolar pulses 3500 as explained in Figure 4A. Between the individual bipolar pulses 3500, there are intervals without pulses. These intervals are the pulse pauses. In this example, two pulse pauses, 3211 and 3212, are shown. In this illustrative example, the pulse pause 3211 is 30 ms or approximately 33.3 Hz. The pulse pause in the second pulse pause is 70 ms or approximately 14.3 Hz. The pulse height, and thus the amplitude, can also be read. Here, it is 30 mA or -30 mA for each pulse. In general, this amplitude can also differ between the individual pulses 3200.

[0099] The variation is determined not only by the mean value but also by a measure of the dispersion around the mean value. Preferably, the measure of dispersion is the variance. The variation can be stochastic, meaning the variations follow any stochastic distribution around the mean value. The stochastic distributions can be, for example, normal distributions, binomial distributions, Poisson distributions, uniform distributions, or other types of distributions. These distributions can be randomly generated, or alternatively, a fixed set of numbers can be selected from a distribution and iterated over repeatedly. Fixed sets preferably contain at least eight different selected numbers. Figure 9A shows a statistical distribution as a histogram. It depicts the distribution of 2000 randomly generated frequencies. The random distribution is a standard distribution with a mean of 30 Hz and a variance of 6 Hz.

[0100] Figure 9B shows another standard-distributed statistic with a mean of 30 Hz and a variance of 6 Hz, where a frequency cut of 3600 has been made for frequencies below 20 Hz, meaning all frequencies below 20 Hz are not used for the pulse signal. This can have the advantage of creating a continuous state of muscle stimulation, similar to a contraction. Additionally, a frequency cut can also be made for high frequencies, i.e., to exclude frequencies above a certain threshold from the pulse signal. This is not shown here, but can also have advantages, for example, to avoid overtraining certain muscle fiber types.

[0101] The variance can be expressed as a scaled variance, i.e., as a percentage of the mean value, and is preferably less than 60%, preferably at most 40%. For example, the distribution in Figure 9B has a mean of 30 Hz, a variance of 6 Hz, and the scaled variance is 20% (=6 Hz / 30 Hz).

[0102] In a preferred embodiment, the degree of variation can be adjusted via the setting device and / or user interface. Preferably, this adjustment is linear or in marked steps. The variation can also be set to 0%.

[0103] In a particularly preferred embodiment, the setting device allows the continuous-linear or discrete-step adjustment of pulse frequency and / or pulse duration, preferably of both pulse frequency and pulse duration. Alternatively and / or additionally, the degree of variation can also be selected via the setting device and / or user interface by choosing from several predefined settings, wherein such a selection includes at least a first setting for a pulse sequence without parameter variation and a second setting for a pulse sequence with parameter variation.

[0104] Furthermore, the distribution of the variation within the pulse sequence can be selected from one of several available distributions, preferably via the setting device and / or user interface as a number indicating after how many pulses the variation occurs. Alternatively, the variation can also occur in repeating discrete steps, such as a triangular distribution. The steps can be equidistant or randomly distributed.

[0105] In the specific example from Figure 9B, the variation around a mean value is achieved by drawing random frequencies from a Gaussian distribution with a mean value of 30 Hz and a relative variance of 20%, which corresponds to 6 Hz, as the standard deviation, and changing the pulse intervals accordingly, whereby a lower limit of 3600 for the frequencies is not undercut.

[0106] The degree of frequency variation, as it naturally occurs in muscle, can range from 10 to 60%. In a preferred further embodiment, the relative variation corresponds approximately to that which naturally occurs in muscle and is measured using sensor elements such as electromyographic sensors. From the measurement signals, the activation and activation frequencies of individual motor units are calculated, and a frequency distribution is determined over a longer period of measurement. This frequency distribution is used as the basis for varying the frequency during stimulation. The average frequency distribution of all motor units of a muscle can be used, or alternatively, the frequency distribution can be determined and used individually for each individual motor unit or for a group of at least two motor units.

[0107] The stimulation parameters can be varied in several ways. For example, the setting device for adjusting a pulse sequence with respect to at least pulse frequency and / or pulse duration, preferably at least pulse frequency and pulse duration, can be configured such that this adjustment is made continuously linearly or in marked steps. Furthermore, the setting device and / or user interface can be configured to adjust the degree of variation of a parameter to be varied during the application of the pulse sequence, preferably continuously linearly or in marked steps by a scaled variance up to a maximum of 60%, preferably up to a maximum of 40% of the mean value.The setting device and / or user interface may also be configured to select from a selection of several predefined settings of the degree of variation of the parameter to be varied during the supply of the pulse sequence, wherein the selection includes at least a first setting for a pulse sequence without variation of the parameter and a second setting for a pulse sequence with variation of a parameter.

[0108] The variation of a parameter to be varied during the application of a pulse sequence can be continuous or discrete, for example stochastically. Preferably, the parameter to be varied during the application of the pulse sequence can be a first pulse pause and be varied discretely, for example stochastically.

[0109] Further training 3:

[0110] Variation of current paths

[0111] In a particularly advantageous third embodiment, the circuit comprises at least three or more electrode elements of the type already described, and the assignment of pulses, i.e., pulse groups or compact pulses, to different electrode elements from the three or more electrode elements is varied; that is, differently selected electrode elements are used as active electrodes. This varying assignment can be made randomly or following a specific alternating pattern and leads to correspondingly varying current paths within the stimulated muscle, corresponding to the electrodes used as cathode and anode, respectively.

[0112] Figure 10 shows a block diagram for such an exemplary embodiment of the electronic circuit. This block diagram is similar to Figure 7, with identical circuit elements being designated with the same reference numerals. In contrast to Figure 7, the electrical stimulation pulse 3200 generated by the current-voltage amplifier 1400 is subsequently routed through a switching unit 1500, such as a multiplexer, to divide a sequential pulse train into several independent pulses 3300 for multiple electrodes, with micropulse groups each being assigned as an undivided whole to one of the multiple electrodes. The pulses thus divided, with micropulse groups 3300, then flow to the respective electrodes 2000, where they are applied to and into the human body 4000.The varied assignment of pulses with micropulse groups to different electrodes by a switching unit shown is specific to this further development of the invention; for the other features shown in Figure 10 and their function, reference is made to the description of Figure 7.

[0113] Figure 11A schematically shows four stimulation electrodes in an exemplary rectangular arrangement for the vastus medialis. Figure 11B shows, by way of example, two different current pathways 3710 and 3720 through the vastus medialis using electrode elements arranged in a crisscross pattern. These two current pathways are not active simultaneously, but rather sequentially, with non-overlapping pulses or micropulse groups being assigned to the individual electrode elements.

[0114] The variation of current pathways according to the invention, achieved by varying the assignment of pulses or micropulse groups to different electrodes, occurs over the duration of the pulse sequence delivery and serves to slow down or prevent fatigue of the stimulated muscle, thus enabling more effective and longer-lasting stimulation without increasing the pulse amplitude. Furthermore, the asynchronous activation of different current pathways activates a greater number of motor units within a muscle, thereby including larger portions of the muscle in the stimulation.

[0115] In the example shown in Figure 11B, this is achieved by alternately applying pulses or a short pulse sequence to specific electrodes, and then applying pulses or pulse groups to other electrode elements. By assigning pulses to electrode elements in a variety of ways, a correspondingly diverse current paths can be generated and varied. In the electrode arrangement shown, for example, in addition to the intersecting current paths shown, current paths running perpendicular to the plane of the image can also be generated between the two left electrodes and between the two right electrodes.

[0116] Furthermore, several of the three or more electrode elements can be combined to form a virtual electrode, thereby creating new current paths. For example, in the electrode arrangement of Figure 11, the two lower electrodes can be combined and operated with only one of the upper electrodes, whereby the selection of the upper electrode can be varied.

[0117] Electrodes not used for muscle stimulation can be placed on a "floating mass" and thus not connected to any mass. The cathode and anode can be varied, and / or the location of the mass can also be changed.

[0118] The variation of the electrode elements according to the second aspect of the invention can also occur randomly, by randomly selecting two electrodes from the pool of three or more. Preferably, the electrodes are arranged such that the altered current path leads to the same functional effect.

[0119] The variation of current paths through varying electrode assignment can occur with fixed parameters. For example, a pulse sequence set as unchanged can be assigned to a pulse-by-pulse selection of active electrodes from the three or more electrode elements.

[0120] Alternatively, in addition to varying the active electrodes, the pulse sequence to be supplied can also be varied over the duration of its supply with regard to at least one parameter from the group of pulse frequency, pulse duration, pulse profile, pulse pauses and maximum pulse height, or with regard to a selection among pulse sequence programs that differ from each other in at least one of these parameters.

[0121] In a particularly preferred embodiment of this further development, the parameter to be varied is the pulse rate or the pulse interval. To avoid repetition, reference is made to the above description of the second embodiment of the invention. The combined temporal and spatial variation of pulse sequences makes it possible to slow down or prevent fatigue of the stimulated muscle to a greater extent and enables even more effective and longer stimulation without increasing the pulse amplitude.

[0122] A variable electrode placement is known in another context. Prior art uses electrode arrays to compensate for biological diversity. This means that electrode placement must be individually adjusted for each person. This adjustment typically also needs to be made each time the electrodes are reapplied. This problem is circumvented by a sensor array with many possibilities, which can be configured for the individual and for use by manual or automated processes. Here, electrodes are selected from the array that fulfill the desired function; unlike the present invention, the selection of electrodes is not varied over the duration of the pulse treatment.

[0123] If an automatic selection of electrodes according to the prior art described above has several equivalent or nearly equivalent electrode configurations as a solution, one embodiment of the present invention consists in varying the supply of pulse sequences via these configurations for the duration of the pulse sequence supply.

[0124] Further training 4:

[0125] Other elements such as sensors or actuators

[0126] The electronic circuit can contain, in addition to the electrode elements, insulating layers and other elements on its contact surface, such as sensors and / or actuators, for example, spectrometers and / or LEDs. In particular, one or more sensor elements can be placed next to or between the electrode elements, preferably also in direct contact with the skin.

[0127] The sensors are used to measure data and information about the human user, preferably one or more muscle states. These states can include temperature, SpO2 value, electromyographic signals, all ExG signals (EMG, EIS, EEG, EOG, etc.), impedances, vibrations, movements, pulse signals, heart signals, chemical and biological substances in sweat, or similar substances. The sensor signals can be used to adjust or modify the pulse sequence delivered to the electrode elements by the controller.

[0128] Depending on the condition to be measured, electrode elements in electrically conductive contact with the skin or other sensors can be used. It is also possible to use the electrode elements of the circuit according to the invention as sensors outside of muscle stimulation. For example, the electrical muscle activity and / or the electrical muscle activity of the motor units of the stimulated muscle can be detected using electrode elements of the circuit according to the invention and / or additional electrodes as sensors. From this, the frequency distribution of the detected muscle activity can be determined, and on this basis, settings regarding the pulse sequence supplied to the electrode elements by the controller can be made or changed. For this purpose, the electromyographic signal can, for example, be measured with individual sensors or sensor arrays.The activation of individual motor units is then determined from the signal, and their activation frequency is calculated from this activation. Over a suitable period, a frequency distribution can be obtained. This frequency corresponds to the natural variation in how muscles are activated. Advantageously, this activation distribution is used to control the heart rate.

[0129] Alternatively or additionally, different activation distributions can be measured under different stress on the muscles, and a suitable activation distribution can be selected depending on the purpose of muscle stimulation.

[0130] Furthermore, the electronic circuit according to the invention can have a device that measures skin impedance and, if the values ​​are too high, can prevent stimulation and / or detect when there is no contact between the contact surface and human skin. EXAMPLES OF IMPLEMENTATION:

[0131] First embodiment;

[0132] Figure 12A shows an illustrative example of a textile substrate, in this case a pair of shorts 6000, in a stylized representation and without depicting their close-fitting nature. Also in a stylized representation, the figure shows four electrodes 2000 arranged in a rectangle in the region of the vastus medial is, shown with dashed lines because they are located on the inside of the textile for direct skin contact. The electrodes are dry electrodes of the type described in connection with Figure 11 and are manufactured using an additive manufacturing process in printed electronics. The electrically conductive layers on the contact surfaces of the electrodes have a surface area of ​​1600 mm². 2 .

[0133] Also shown in dashed lines are electrical leads 2100, which connect the electrodes 2000 to the control unit 1000 and are also manufactured using an additive manufacturing process of printed electronics.

[0134] The control unit 1000 for supplying the current-controlled generated pulse sequence to the electrodes is constructed as described in connection with Figure 10 and is located, together with a battery 1100, a DC-DC converter, and a Bluetooth Low Energy radio transmitter, in a splash-proof plastic capsule on the outer surface of the textile on the thigh. The Bluetooth Low Energy radio transmitter enables data communication with a smartphone, on which the user interface and setting device are implemented together as an application. The user interface provides an on / off switch, a pulse intensity control, and a setting screen for the mean pulse frequency and its scaled variance for users and caregivers. Furthermore, the circuit is designed so that, according to the invention, the pulse sequences contain micropulse groups that increase the frequency by the set number of micropulses (divided by two).This increases the frequency from a few kHz to up to 1 MHz. The impedance then lies in the range between 1 kΩ and 5 kΩ, which corresponds to a contact quality comparable to that of gelled electrodes.

[0135] According to the third embodiment of the present invention, the circuit is designed to regularly vary the assignment of micropulse groups between the four different electrode elements every ten micropulse groups between diagonally opposite electrode pairs during the pulse train application, so that two diagonally opposite electrodes are "active" as cathode and anode, and the two remaining electrodes are suspended and inactive. In this way, two different current paths are generated, which intersect in plan view as shown schematically in Figure 8A and change every ten micropulse groups.

[0136] Second example:

[0137] The second embodiment has all the features of the first embodiment; repetitive illustrations are omitted.

[0138] Additionally, the circuit is designed so that the pulse sequences supplied to the four electrode elements in varying arrangements, in this case sequences of micropulse groups, have a stochastically varying pulse frequency between 20 Hz and 45 Hz with a mean value of 30 Hz, a scaled variance of 20%, and a frequency distribution as shown in Figure 9B. Variant of the first and second embodiments:

[0139] Both embodiments can be extended by an additional sensor. Figure 12B shows the elements of Figure 12A described above, with the addition of a sensor 2100. This sensor is located centrally between the four electrode elements and is designed as a fifth electrode with an electrically conductive contact surface.

[0140] The electronic circuit, based on this variant of the two implementation examples, is designed to measure the electrical muscle activity of the vastus medialis' motor units during its natural movement using a total of five electrodes. From this, the circuit determines the muscle's natural frequency distribution in its current state and displays it on a smartphone. This measurement can be performed, for example, before the start of a muscle stimulation treatment, and the displayed frequency distribution can serve as a guide for the user or caregiver when setting the pulse rate for muscle stimulation. Furthermore, the smartphone application can store, display, and output data on the history of muscle stimulation treatments and the respective muscle state.

Claims

PATENT CLAIMS:

1. Electronic circuit for muscle stimulation, comprising several electrode elements on a textile carrier material designed for wear on the human body, each with an electrically conductive layer on a contact surface for electrically contacting a section of the skin of the human body, wherein the textile carrier material is designed such that, when worn on the human body, the contact surfaces of several electrode elements are in contact with different sections of the skin of the human body in areas of a predetermined same muscle; a control unit designed to supply the several electrode elements with a sequence of charge-neutral current pulses, preferably averaging at least 1 ms, and a user interface to switch off the supply of the current pulses and preferably also to switch them on and to regulate their pulse amplitude;and an adjustment device for setting a pulse sequence to be supplied by the control to the electrode elements with respect to at least one parameter from the group consisting of pulse frequency, pulse duration, pulse profile, pulse pauses and maximum pulse height, or with respect to a selection among pulse sequence programs that differ from each other in at least one of these parameters, characterized in that the circuit is configured such that a set pulse sequence has first pulse pauses of at least 5 ms in duration between at least two, preferably at least three successive pulses, and second pulse pauses of between 3 ps and 1 OOps between at least 4 and at most 400 successive pulses.

2. Electronic circuit according to claim 1, wherein the control is configured to generate the pulse sequence set with the setting device in a current-controlled manner by varying the voltage of the pulses with respect to their amplitude and / or pulse profile until a current value predetermined for control is reached.

3. Electronic circuit according to claim 1 or claim 2, wherein the setting device is configured for setting at least one parameter from the group consisting of pulse frequency, pulse duration and pulse pauses and is configured to set, in the case of setting the pulse duration parameter, the next time interval between two first pulse pauses, in the case of setting the pulse pauses parameter, the duration of first pulse pauses, and in the case of setting the pulse frequency parameter, the inverse of the duration of first pulse pauses.

4. Electronic circuit according to the preceding claim, wherein the circuit is further configured to vary the pulse sequence in at least one parameter affected by the setting during and over the duration of the pulse sequence supply.

5. Electronic circuit according to the preceding claim, wherein the at least one parameter to be varied comprises the pulse frequency or the pulse pause.

6. Electronic circuit according to one of the preceding claims, wherein the setting device is further configured to set a pulse sequence to determine whether and optionally how many first pulse pauses follow one another immediately.

7. Electronic circuit according to one of the preceding claims, wherein the setting device is further configured to change the duration of second pulse pauses and / or their relative frequency in relation to first pulse pauses.

8. Electronic circuit according to one of the preceding claims, further comprising at least one sensor element which is arranged on the textile carrier material next to and / or between the several electrode elements and is designed to detect a state of the muscle when worn on the human body, wherein the circuit is further designed to change the duration of second pulse pauses and / or their relative frequency in relation to first pulse pauses on the basis of the detected muscle state.

9. Electronic circuit according to one of the preceding claims, further configured to supply a first pulse sequence with several first pulse pauses of the same duration and the same time interval to the next first pulse pause, between successive such first pulse pauses groups of several second pulse pauses of the same duration and the same time interval to the next second pulse pause, and several such groups of second pulse pauses with a different number of associated second pulse pauses, and to Supplying a second pulse sequence, in which the duration of second pulse pauses and / or the time interval to the next second pulse pause and / or their relative frequency in relation to first pulse pauses is determined depending on a respective voltage or on a respective ratio between voltage and current when supplying several such groups with different numbers of each associated second pulse pauses in the first pulse sequence.

10. Electronic circuit according to one of the preceding claims 2, comprising three or more electrode elements on the textile carrier material, each with an electrically conductive layer on a contact surface for electrically contacting a section of the skin of the human body, wherein the circuit is further configured to vary the assignment of pulses to different electrode elements from the three or more electrode elements during and over the duration of the pulse sequence supply, and optionally further to vary the pulse sequence in at least one parameter affected by the setting.

1. Electronic circuit according to the preceding claim, wherein the textile carrier material is designed such that, when worn on the human body, the contact surfaces of the three or more electrode elements are in contact with different sections of the skin of the human body in areas of a predetermined same muscle, the contact surfaces of at least two of the three or more electrode elements being arranged in positions different in a first direction, and the contact surfaces of at least two of the three or more electrode elements being arranged in positions different in a second direction from the first direction, and wherein the circuit is designed to assign pulses to the first and second electrode elements during and over the duration of the supply of an unchanged pulse sequence. vary.

12. Electronic circuit according to one of the preceding claims, further comprising at least one sensor element which is arranged on the textile carrier material next to and / or between the several electrode elements and is designed to detect a state of the muscle when worn on the human body, wherein the circuit is further designed to adjust a pulse sequence to be supplied to the electrode elements by the control unit on the basis of the detected muscle state.

13. Control method for an electronic circuit according to any of the preceding claims, comprising the steps: Capturing a setting of a pulse sequence to be supplied by the control unit to the electrode elements with respect to at least one parameter from the group of pulse frequency, pulse duration, pulse profile, pulse pauses and maximum pulse height, or with respect to a selection among pulse sequence programs that differ in at least one of these parameters, current-controlled generation of a pulse sequence based on the captured setting of the controlled pulse sequence to the multiple electrode elements and Supplying the generated pulse sequence to the multiple electrode elements, wherein the supplied pulse sequence has first pulse pauses of at least 5ms duration between at least two, preferably at least three successive pulses, and second pulse pauses of between 3ps and 100ps between at least 4 and at most 400 successive pulses.

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