System and device for electrotactile interference stimulation

Abstract

The present invention relates to a device (14) for actuating signal transmitters for generating a stimulation, comprising: an input interface (16) for receiving stimulation data having information relating to a stimulation to be generated; an analysis unit (18) for determining an actuation signal for actuating a signal generator (20) on the basis of the stimulation data; a signal generator (20) which is designed to generate signals which are periodic at least in some portions on the basis of the actuation signal; and an output interface (26) for transmitting the signals which are periodic at least in some portions to the signal transmitters; wherein the analysis unit (18) is designed to generate the actuation signal in such a way that the signal generator (20) transmits different signals to the output interface (26), the superposition of which leads to the excitation of the movable stimulation to be generated. The present invention furthermore relates to a corresponding system, item of clothing and method.

Description

[0001] System and device for electrotactile interference stimulation

[0002] The present invention relates to a device for controlling preferably at least four signal transmitters, in particular in the form of cables with electrodes connected thereto, for generating stimulation. The present invention further relates to a corresponding system, garment, and method.

[0003] Tactile interfaces between machines and humans are state of the art in many areas. Examples include vibrations on smartphones when buttons are pressed, or in the automotive sector. However, these stimulations primarily affect entire components.

[0004] Current approaches to stimulating cutaneous nerves face technical challenges. Both mechanical and electrical stimulation methods have limitations. Mechanical stimulation methods often require complex devices that are susceptible to external influences. The actuators used are expensive to manufacture and usually only allow for localized stimulation at fixed locations. Mobile actuators are complex in design and move slowly. Furthermore, they are often quite heavy.

[0005] In classical electrical stimulation, the stimulation is also limited to a fixed location. The penetration depth of the electrical signal can only be influenced by the distance between the electrodes.

[0006] Interference stimulation, a specific form of electrical stimulation, has not yet been used for tactile stimulation of cutaneous nerves in combination with suitable electrode placement. An approach for variable and dynamic interference stimulation is also lacking.

[0007] The invention thus solves the problem of creating a means of stimulating tactile sensations on the skin. In particular, it aims to enable the stimulation of various sensations on the skin, such as rubbing, stroking, vibration, pressure, pain, heat, and stinging. Furthermore, stimulation of variable stimulation sites with continuous location adjustment is possible. In addition, a combination with other types of stimulation, such as heat, mechanical, acoustic, and visual, can be achieved. A combination with other electrical stimulation methods, for example, transcutaneous direct current stimulation, high-frequency stimulation for neuronal blocking, or transcutaneous electrical nerve stimulation (TENS) for tactile stimulation, is particularly advantageous. Furthermore, a combination with stimulation stimuli for muscle stimulation is also possible.

[0008] Currently, temporal interference stimulation typically uses at least two sinusoidal signals, or more signals for better focusing, from spatially separated electrode pairs. The signal frequency is high enough that no action potential is triggered in the nerve.

[0009] However, both signals have different frequencies. These two signals overlap in the tissue. If the currents triggered by both signals are equally strong in the tissue, a strong beat frequency is created. This beat frequency, in combination with the nonlinear properties of the neuronal cell membrane, triggers action potentials. This can induce an action potential and thus stimulation. In typical applications, the electrodes are deliberately positioned so that the stimulation effect is triggered in deeper tissue, for example, in the muscle or brain, without producing sensory perceptions as an unwanted side effect.

[0010] In one aspect of the invention, several approaches are combined. The electrodes are deliberately placed closer together to stimulate the sensory fibers in the skin or subcutaneous tissue. Furthermore, the beat frequency is not focused on a single point, but rather spatially shifted by altering the signal characteristics of the sources, thus creating the perception of movement. Additionally, phase-controlled interference stimulation can be used as an alternative to temporary interference stimulation.

[0011] In one aspect, the invention relates to a device for controlling preferably at least four signal transmitters, i.e., cables and electrodes, for generating stimulation, comprising: an input interface for receiving stimulation data with information on the stimulation to be generated; an analysis unit for determining a control signal for controlling a signal generator based on the stimulation data; a signal generator configured to generate preferably at least two, at least sectionally periodic, signals based on the control signal; an output interface for transmitting the at least sectionally periodic signals to the signal transmitters, wherein the analysis unit is configured to generate the control signal such that the signal generator transmits different signals to the output interface, the superposition of which in the biological tissue is used to stimulate the stimulation to be generated.This leads to variable stimulation. Stimulation can, for example, be a sensation of rubbing, stroking, vibration, pressure, pain, heat, and / or stinging, preferably on the skin. It depends on the strength or intensity and the properties of the superposition. These can include variations in intensity, amplitude, the number of pulses per unit of time, or pulse width. Furthermore, the stimulation and the resulting sensation can depend on the electrode spacing and the attenuation of signals in the tissue. It is understood that the superposition can also include modulation or a pulse rhythm to elicit a user-specific stimulation or sensation. The various sensations can therefore be user-specific and can be tailored to the user, for example, through calibration. In this process, the user could provide feedback.what he feels in response to which stimulus, i.e., whether it is a pulling sensation, a stinging sensation, pain, etc.

[0012] In a further aspect, the present invention relates to a system with a device as defined above and at least four signal transmitters connected to the output interface, and a garment with a system as defined above, wherein the electrodes are arranged on an inner side of the garment facing the skin of the wearer and point inwards, i.e. towards the wearer.

[0013] Finally, in a further aspect, the present invention relates to a method for generating stimulation, preferably by means of a device, a system or a garment as defined above, comprising the steps of: receiving stimulation data with information on a stimulation to be generated; determining a control signal for controlling a signal generator based on the stimulation data; generating at least sectionally periodic signals based on the control signal; transmitting the at least sectionally periodic signals to the signal transmitters; wherein the control signal is generated such that different signals are present at the output interface, the superposition of which leads to the excitation of the spatially variable stimulation to be generated.

[0014] An input interface for receiving stimulation data allows the device to be advantageously integrated into various systems. In particular, the input interface can be configured to receive the stimulation data in abstract form. Preferably, the intensity, speed, location, and, preferably, the velocity of the stimulation, as well as the type of stimulation to be elicited, are specified. An analysis unit for determining a control signal enables the received data to be analyzed, processed, and used to control a signal generator accordingly. Based on the control signal calculated by the analysis unit, the signal generator produces at least sectionally periodic signals, which can be transmitted to the signal transmitters via the output interface.These periodic signals are designed in such a way that they pass through the signal transmitters and preferably through the skin of a user and superimpose at the pre-calculated location, with this superposition leading to the excitation of the stimulation to be generated, which can be highly variable, in particular in terms of location and intensity.

[0015] Methods for altering superposition can be combined when more than two channels are involved. Superposition changes can occur periodically, in groups, or statistically. This allows for the generation of dynamic tactile signals and stimuli on the skin.

[0016] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the present invention. In particular, the method can be implemented according to the embodiments described for the device or system.

[0017] In a preferred embodiment, the analysis unit is configured to generate the control signal such that a superposition of the different signals forms a maximum at a point to be stimulated. This maximum can be shifted by manipulating the phase, amplitude, and / or frequency of at least one of the different signals. By manipulating the phase, amplitude, or frequency, a superposition of the signals at a preferred point can be generated with technical ease. The superimposed signals thus produce the desired stimulation, which can be perceived, in particular, as a tactile sensation. Using the aforementioned methods, the maximum can be shifted quickly, allowing a moving stimulation to be perceived.Preferably, the maximum can be modulated so that individual nerve cells can be specifically stimulated by this modulated superposition to generate a desired stimulation and evoke a corresponding sensation.

[0018] In a further advantageous embodiment, the analysis unit is configured to generate the control signal such that a frequency manipulation comprises a difference between the two signals in the range of 1 hertz to 500 kilohertz, in the range of 1 kilohertz to 200 kilohertz, and particularly preferably in the range of 1 kilohertz to 10 kilohertz. Additionally or alternatively, the analysis unit is configured to generate the control signal such that a phase manipulation comprises a difference between the two signals in the range of 0 milliseconds to 100 milliseconds, preferably in the range of up to 5 milliseconds.Finally, the analysis unit is additionally or alternatively configured to generate the control signal such that an amplitude manipulation encompasses a difference between the two signals ranging from 5% to 95%, preferably between 20% and 80%, and very preferably between 40% and 60%. The aforementioned ranges, which can be used individually or in combination to influence the superposition of the two signals on the skin, enable highly variable and dynamic stimulation generation. In particular, a combination of these manipulations allows for improved and more precise control of the stimulation. The stimulation can be positioned and controlled with pinpoint accuracy.Advantageously, the analysis unit is configured to generate the control signal such that the time interval between two constructively interfering superposition states is preferably in the range of 2 milliseconds to 5 seconds, more preferably between 2 milliseconds and 2 seconds, particularly preferably between 5 milliseconds and 1 second, and most preferably between 6 milliseconds and 500 milliseconds. These ranges ensure that a superposition maximum does not need to be shifted spatially, but rather that superposition maxima are generated at different locations within a short time interval, thus creating the impression of a moving stimulation. This reduces both the control effort and the energy input into the user's skin.

[0019] In an advantageous embodiment of the system, two signal transmitters are combined into an electrode patch with two electrodes arranged at a distance of less than 100 millimeters, preferably less than 50 millimeters, and particularly preferably less than 15 millimeters from each other. These distances refer to two electrodes of an electrode pair, to which corresponding signals can be applied. Due to the small distance between the electrodes, the system enables stimulation of the sensory fibers in the skin or subcutaneous tissue. Contrary to previous practice and understanding, the electrodes are thus arranged close together to achieve the desired stimulation. It is understood that additional electrode pairs can also be used. Furthermore, it is conceivable to combine several electrode pairs into different stimulation groups.Furthermore, it is conceivable to connect several electrodes to a common counter electrode, so that, for example, four outer electrodes are each coupled to the same inner electrode.

[0020] In a particularly preferred embodiment of the system, the electrodes have an area of ​​1 mm². 2 up to 100 mm 2 , preferably 2 mm 2 up to 80 mm 2 , 2 mm 2 up to 50 mm 2 , 1 mm 2 up to 20 mm 2The advantageous electrode surfaces ensure sufficient contact with the skin to reliably achieve stimulation. At the same time, a small electrode surface area increases the wearing comfort of such a system. The selected areas represent a preferred compromise between electrode contact and wearing comfort. A person skilled in the art will recognize that different electrode surfaces are advantageous depending on the application. The electrode surface area is preferably no more than 70 mm². 2 , at most 50 mm 2 , at most 40 mm 2 , at most 30 mm 2 , at most 20 mm 2 , at most 15 mm 2 , at most 10 mm 2 , at most 5 mm 2 or at most 2 mm 2 .

[0021] In a further advantageous embodiment of the system, the electrodes have a round base shape, in particular an oval or rounded base shape, a rectangular base shape, in particular the shape of a regular or irregular square, rectangular, trapezoidal polygon, or the shape of an octagon or hexagon. The electrode geometries mentioned above allow for the selection of an optimal geometry for each application. Oval or round electrodes are particularly suitable for integration into clothing, as the electrodes have no corners, thus increasing wearing comfort and preventing damage to the clothing from the electrodes. Rectangular electrodes are particularly suitable for medical applications and their shape can be adapted to the body characteristics of a patient.In the medical field, wearing comfort usually takes a back seat and optimal stimulation takes center stage, so a combination of different geometries can be used depending on the body region where the electrodes are to be attached.

[0022] The device according to the invention can be easily integrated into clothing. For example, the electrodes of the device or system can be easily incorporated and integrated into sleeves, gloves, helmets, or similar items. The signal transmitters used can be manufactured simply and cost-effectively, for example, in the form of electrodes that are preferably flexible and bendable. The signal transmitters are positioned on the skin.

[0023] In a preferred embodiment, no electrode gel or other liquid, solid, viscous, or gel-like substance is required between the signal transmitter and the skin. However, electrode gel can improve the properties.

[0024] Since the electrodes of the system according to the invention do not need to be in direct contact with the skin, the invention is particularly suitable for use in prostheses, such as leg or hand prostheses. Tactile feedback can be transmitted in these cases.

[0025] Further applications arise in the field of telestimulation, for example in the area of ​​human-machine interfaces for robot control or in stroke rehabilitation. The invention can also be used for early diagnosis of autism, as it induces movement of the stimuli between the two electrodes. Other applications include stimulation during psychological tests.

[0026] In general, "section-periodic" can be understood to mean that a signal alternately has positive and negative signs. The signal oscillates between positive and negative values. Section-periodic signals are signals that preferably consist of several sections, each of which can be a periodic signal. In general, the phase, amplitude, and frequency can differ from section to section. The periods of the individual sections need not be the same, and the signal can change in its shape, strength, speed, or frequency. The description and explanation are to be understood as examples and not as limiting. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to a person skilled in the art when using the present invention.The invention is described and explained in more detail below with reference to some selected embodiments in conjunction with the accompanying drawings. The drawings show:

[0027] Figure 1: A schematically simplified representation of a system according to the invention;

[0028] Figures 2a to 2: Schematic representations of exemplary signals that can be applied to the electrodes, and their superposition;

[0029] Figure 3: Schematic representation of the spread of signals, for example on the skin of a user;

[0030] Figure 4: Analogous to Figure 3. A superposition of the signals at a different location.

[0031] Figures 5a to 5c: Examples of different electron pads with different electrode arrangements;

[0032] Figure 6: Examples of garments with electron pads or a system according to the invention; and

[0033] Figure 7: Schematic representation of the steps of a method according to the invention.

[0034] Figure 1 schematically shows a system 10. The system 10 comprises a computer 12, which is connected to a device 14 for controlling signal transmitters 24 to generate stimulation.

[0035] The device 14 has an input interface 16 which is connected to the computer 12. It is understood that the computer 12 is chosen only symbolically and any electronic unit capable of transmitting stimulation data can be used in its place. The input interface 16 is configured to receive stimulation data containing information about the stimulation to be generated.

[0036] The device 14 further comprises an analysis unit 18. The analysis unit 18 receives the stimulation data and, based on the stimulation data, determines a control signal for controlling a signal generator 20.

[0037] The signal generator 20 is designed to generate at least two, at least sectionally periodic, signals based on the control signal, which are ultimately transmitted to electrodes 22 of the signal transmitters 24 by means of an output interface 26 and unspecified lines.

[0038] The control signal is generated such that the signal generator transmits 20 signals to the output interface 26 and finally to the electrodes 22. The superposition of the signals leads to the excitation of the variable stimulation to be generated.

[0039] For the sake of simplicity, the example shown depicts only four electrodes 22 arranged on a forearm to generate a corresponding stimulation based on input via the computer 12, i.e., the transmission of stimulation data.

[0040] The term "variable location" means, in particular, that the stimulation can be generated at any point, preferably within the area covered by the electrodes 22. It is understood that, for this purpose, preferably different types of signals are applied to the different electrodes 22. In some cases, a superposition can also be caused by identical signals at the desired location.

[0041] Stimulation data can include, for example, the intensity and location of the stimulation. Based on this data, the analysis unit can calculate corresponding signals, preferably with known electrode spacing and positions, and generate them using a control signal and a signal generator. It is understood that the analysis unit 18 and the signal generator 20 can also be implemented in a single unit. The representation chosen here serves for clarity and a better understanding of the invention.

[0042] Figures 2a and 2b each show graphs of 28 periodic signals, in particular sinusoidal signals. The intensity of the signal is plotted against a time interval.

[0043] The two signals are temporarily out of phase with each other, but have the same frequency and amplitude.

[0044] When the two signals are superimposed, a superposition signal can occur, for example, as shown in diagram 28 of Figure 2c. It is therefore possible to achieve signal cancellation at certain points and signal amplification and superposition at other points using the two signals. The cancellation / amplification effect can vary in intensity at different locations. To change the location of the effect, the amplitudes in the respective electrode pairs can be adjusted, for example.

[0045] Figure 3 schematically shows a top view of an arrangement of four electrodes 22, which are connected to the output interface of the device (not shown) by means of cables 30. In the scene depicted in Figure 3, identical signals are present at all electrodes 22, so that a positive superposition, i.e., maximum interference, is preferably achieved exactly between the four electrodes 22. This is illustrated in Figure 3 by two identical, overlapping circles.

[0046] Figure 4 shows a superposition at a different location, analogous to Figure 3. The position of the superposition can be varied by manipulating the signals applied to electrodes 22. In the example shown, this is illustrated by two ellipses that superimpose, shifted to the right compared to Figure 3.

[0047] Figures 5a to 5c show various electrode patches 32 or pads that can be used to generate stimulations with a device according to Figure 1. It is understood that the individual electrodes 22 are each connected to the electrode patch 32 by cables, the cables being routed to a flat connector on the right side in the illustrated embodiments in order to enable the electrode patch 32 to be connected to an output interface of a device and to selectively control the electrodes 22.

[0048] For better clarity, only one electrode 22 on each electrode patch 32 is marked with a reference symbol.

[0049] Figure 5a shows an arrangement of electrodes in three rows and six columns, where two electrodes 22 can be combined to form an electrode pair in order to trigger a corresponding stimulation.

[0050] It is understood that a double-row arrangement of the electrodes 22 is also possible, as shown in Figure 5b.

[0051] Furthermore, it is not necessary for the electrodes 22 to be arranged strictly in rows and columns. An alternating arrangement is shown in Figure 5c only as an example.

[0052] A person skilled in the art will recognize that other electrode arrangements are possible and that the simplified examples shown above serve to better understand the invention.

[0053] Figure 6 shows exemplary articles of clothing 36 equipped with electrode patches 32, electrodes 22 and / or a system 10. For example, it is conceivable to integrate the electrode patches 32 and a system 10 into a close-fitting virtual reality suit in order to preferably elicit corresponding stimulations on the entire skin surface of a user.

[0054] Furthermore, it is conceivable to integrate electrodes 22, electrode patches 32 and / or a system 10 into a glove, in particular to trigger feedback when operating a machine or to train or simulate the operation of a machine and to train personnel.

[0055] Furthermore, it is conceivable to integrate a System 10, electrodes 22 and / or electrode patches 32 invisibly into everyday clothing and, for example, to link them with a smartphone and / or virtual reality glasses in order to trigger corresponding stimulations in everyday life or, for example, during gaming.

[0056] In particular, it may be considered to trigger a corresponding tactile stimulation by means of such a garment instead of a ringing or vibration of a telephone.

[0057] Figure 7 schematically illustrates the steps of a method according to the invention.

[0058] In a first step S1, stimulation data is received with information about a stimulation to be generated.

[0059] In a second step S2, a control signal is then determined to control a signal generator based on the stimulation data.

[0060] In a third step S3, at least partially periodic signals are generated based on the control signal. Finally, in a fourth step S4, these at least partially periodic signals are transmitted to the signal transmitters.

[0061] The control signal is generated in such a way that different signals are present at the output interface, the superposition of which leads to the excitation of the spatially variable stimulation to be generated.

[0062] In an optional step S5 (not shown), a user is then stimulated by means of electrodes attached to the user, to which the previously described section-by-section periodic signals are transmitted.

[0063] The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are to be understood as examples and not as limiting. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to a person skilled in the art when using the present invention and upon a detailed analysis of the drawings, the disclosure, and the subsequent claims.

[0064] In the patent claims, the words "comprise" and "with" do not preclude the presence of further elements or steps. The undefined article "a" or "an" does not preclude the presence of multiple elements. A single element or unit can perform the functions of several of the units mentioned in the patent claims. An element, unit, interface, device, and system can be implemented partially or completely in hardware and / or software. The mere mention of some measures in several different dependent patent claims is not to be understood as precluding the advantageous use of a combination of these measures. A computer program or computer program product can be stored / distributed on a non-volatile data carrier, for example, on optical storage media or on a solid-state drive (SSD).A computer program can be distributed together with hardware and / or as part of hardware, for example via the internet or via wired or wireless communication systems. Reference punctuation in the patent claims is not to be understood as limiting.

[0065] Reference symbol list

[0066] 10 System

[0067] 12 computers

[0068] 14 Device 16 Input interface

[0069] 18 analysis units

[0070] 20 Signal generator

[0071] 22 electrodes

[0072] 24 Signal transmitters 26 Output interface

[0073] 28 Diagram

[0074] 30 cables

[0075] 32 electrode patch

[0076] 36 items of clothing

Claims

Patent claims 1. Device (14) for controlling signal transmitters to generate a stimulation, comprising: an input interface (16) for receiving stimulation data with information on a stimulation to be generated; an analysis unit (18) for determining a control signal for controlling a signal generator (20) based on the stimulation data; a signal generator (20) configured to generate at least sectionally periodic signals based on the control signal; and an output interface (26) for transmitting the at least sectionally periodic signals to the signal transmitters; wherein the analysis unit (18) is configured to generate the control signal such that the signal generator (20) transmits different signals to the output interface (26), the superposition of which leads to the excitation of the spatially variable stimulation to be generated.

2. Device (14) according to the preceding claim, wherein the analysis unit (18) is configured to generate the control signal such that a superposition of the different signals forms a maximum at a point to be stimulated, which is spatially variable by phase manipulation, amplitude manipulation and / or frequency manipulation of at least one of the different signals.

3. Device (14) according to one of the preceding claims, wherein the analysis unit (18) is configured to generate the control signal such that a frequency manipulation comprising a difference in the range of 1 Hz to 500 kHz, preferably in the range of 1 kHz to 200 kHz, particularly preferably in the range of 1 kHz to 10 kHz between the two signals; a phase manipulation comprising a difference in the range of 0 ms to 100 ms, particularly preferably in the range of up to 5 ms between the two signals; and / or an amplitude manipulation comprising a difference in the range of between 5% and 95%, preferably between 2% and 80%, very preferably between 4% and 60% between the two signals.

4. Device (14) according to one of the preceding claims, wherein the analysis unit (18) is configured to generate the control signal such that a time interval between two superposition states is preferably in the range between 2 ms and 5 s, more preferably between 2 ms and 2 s, very preferably between 5 ms and 1 s, and particularly preferably between 6 ms and 500 ms.

5. System (10) comprising a device (14) according to one of the preceding claims and at least four signal transmitters (24) connected to the output interface (26).

6. System (10) according to the preceding claim, wherein two signal transmitters (24) are combined to form an electrode patch (32) with at least two electrodes (22) which are each arranged at a distance of less than 100 mm, preferably less than 50 mm, particularly preferably less than 15 mm from each other.

7. System (10) according to one of claims 5 or 6, wherein the electrodes (22) have an area of ​​1 mm² 2 up to 100 mm 2 , preferably 2 mm 2 up to 80 mm 2 , of 2 mm 2 up to 50 mm 2 , of 1 mm 2 up to 20 mm 2 exhibit.

8. System (10) according to one of claims 5 to 7, wherein the electrodes (22) have a round basic shape, in particular an oval or rounded basic shape; an angular basic shape, in particular the shape of a regular or irregular, square, rectangular, trapezoidal polygon, and / or the shape of an octagon or hexagon.

9. Garment (36) with a system (10) as defined above, wherein the electrodes (22) are arranged on an inside of the garment (36) facing the skin of a wearer of the garment (36) and point inwards.

10. Method for generating stimulation, preferably by means of a device (14) according to one of claims 1 to 4, a system (10) according to one of claims 5 to 8 or a garment (36) according to the preceding claim, comprising the steps: Receiving (S1 ) stimulation data with information about the stimulation to be generated; Determining (S2) a control signal to control a signal generator (20) based on the stimulation data; Generating (S3) at least sectionally periodic signals based on the control signal; and Transmitting (S4) the at least sectionally periodic signals to the signal generators; wherein the control signal is generated in such a way that different signals are present at the output interface (26), the Superposition leads to the stimulation of the positionally variable stimulation to be generated.

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