METHOD FOR SUPPRESSING INTERFERENCE SIGNALS IN AN ELECTROMYOGRAM MEASUREMENT

Abstract

The disclosure relates to a method for separating useful and unwanted signals in an electromyographic (EMG) measurement in an electrically active region of muscles and / or for suppressing unwanted signals in the EMG measurement, comprising the following steps: capturing a first signal with at least one first sensor device on a first muscle group, wherein the first signal has a first EMG signal component and a first EMG unwanted component; capturing a second signal with at least one second sensor device on the first muscle group, wherein the second signal has a second EMG signal component and a second EMG unwanted component; determining a combined signal based on the first signal and the second signal to suppress the first and / or the second EMG unwanted component.Furthermore, the disclosure relates to the use of the method for monitoring at least one muscle group, in particular respiratory muscles, preferably for diaphragmatic monitoring, and / or for controlling a ventilator, and / or for controlling and / or monitoring prostheses and / or orthoses, and / or for motion analysis. In addition, a computer-implemented method, a computer program product, a computer-readable storage medium, and a device for separating useful and interference signals in an EMG measurement in an electrically active region of muscles and / or for suppressing interference signals in the EMG measurement are provided.

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a method for separating useful and unwanted signals in an electromyographic (EMG) measurement in an electrically active region of muscles and / or for suppressing unwanted signals in the EMG measurement. The present invention also relates to the use of the method according to the invention for monitoring at least one muscle group, in particular respiratory muscles, preferably for diaphragmatic monitoring, and / or for controlling a ventilator, and / or for controlling and / or monitoring prostheses and / or orthoses, and / or for motion analysis. Furthermore, a computer-implemented method, a computer program product, a computer-readable storage medium, and a device for separating useful and unwanted signals in an EMG measurement in an electrically active region of muscles and / or for suppressing unwanted signals in the EMG measurement are provided. DESCRIPTION

[0002] Electromyography (EMG) is a method for recording the electrical activity generated during muscle contraction, such as muscle tension. When a muscle is stimulated, an action potential is generated in the muscle fibers, which, due to the anisotropic conductivity properties of a muscle fiber, propagates preferentially in the fiber direction. EMG records the summed potential of all active muscle fibers, measuring the muscle action potentials by differential voltage measurement. These signals can be recorded either invasively using needle electrodes or non-invasively using surface electrodes. The information contained in the signals is frequently used to control prostheses or myoprostheses, but also allows conclusions to be drawn about the health status of a muscle or muscle group.

[0003] EMG signals, particularly surface EMG signals (e.g. EMG signals that propagate across the surface of the skin), which can also be referred to as sEMG signals, can be interfered with by other signals, e.g. superimposed voltage signals. These can be, for example, coupled-in 50 / 60 Hz components from an electrical network. Another example in the recording and / or detection of EMG and / or sEMG signals, for example near the heart, would be superposition with the electrocardiography signal (ECG). Since the frequency ranges of useful signals, e.g. EMG and / or sEMG signals, and interference or interference signals such as ECG signals or others, overlap and / or lie in a similar frequency range, these components must be differentiated or separated from one another, e.g. for further analysis.

[0004] Separation is typically achieved using conventional filtering techniques. For example, analog and digital frequency filters can be used to separate useful and interfering signals and / or to suppress the interfering signals. Other digital signal processing methods, for example, employ complex adaptive wavelet filter banks or model-based approaches. However, these conventional methods and / or filtering techniques are only partially reliable or accurate, require high computing power, and do not operate in real time. Furthermore, they exhibit high latencies.

[0005] It is an object of the present invention to overcome the disadvantages of the known prior art and in particular to provide an improved method for separating useful and interference signals in an electromyographic, EMG, measurement in an electrically active region of muscles and / or for suppressing interference signals in the EMG measurement. BRIEF DESCRIPTION OF THE INVENTION

[0006] The problem is solved by the features of the independent claims. The dependent claims describe preferred embodiments. Further aspects, advantages, and features emerge from the dependent claims, the description, and the accompanying drawings.

[0007] According to a first aspect, the invention relates to a method for separating useful and interference signals in an electromyographic, EMG, measurement in an electrically active region of muscles and / or for suppressing interference signals in the EMG measurement, which comprises the following steps: - detecting a first signal with at least one first sensor device on a first muscle group, wherein the first signal has a first EMG signal component and a first EMG interference component; - detecting a second signal with at least one second sensor device on the first muscle group, wherein the second signal has a second EMG signal component and a second EMG noise component; - Determining a combined signal based on the first signal and the second signal to suppress the first and / or the second EMG interference component.

[0008] According to a second aspect, the invention relates to the use of the method according to the invention for monitoring at least one muscle group, in particular respiratory muscles, preferably for diaphragm monitoring, and / or for controlling a ventilator, and / or for controlling and / or monitoring prostheses and / or orthoses, and / or for movement analysis.

[0009] According to a third aspect, the invention relates to a device for data processing, comprising means for carrying out the steps of the method according to the invention.

[0010] According to a fourth aspect, the invention further relates to a computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the method according to the invention.

[0011] According to a fifth aspect, the invention further relates to a computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the steps of the method according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following describes the elements of the invention. These elements are listed with specific embodiments, which can be combined in any manner and in any number to create additional embodiments. The variously described examples and preferred embodiments should not be construed to limit the present invention only to the explicitly described embodiments. This description of the invention should be understood to support and include embodiments that combine two or more of the explicitly described embodiments or that combine one or more of the explicitly described embodiments with any number of the disclosed and / or preferred elements.Furthermore, all permutations and combinations of all described elements in this application should be considered as disclosed by the description of the present application, unless the context indicates otherwise.

[0013] According to the first aspect, the invention relates to a method for separating useful and interference signals in an electromyographic, EMG, measurement in an electrically active region of muscles and / or for suppressing interference signals in the EMG measurement, which comprises the following steps: - detecting a first signal with at least one first sensor device on a first muscle group, wherein the first signal has a first EMG signal component and a first EMG interference component; - detecting a second signal with at least one second sensor device on the first muscle group, wherein the second signal has a second EMG signal component and a second EMG noise component; - Determining a combined signal based on the first signal and the second signal to suppress the first and / or the second EMG interference component.

[0014] An "electromyographic measurement" can be understood as a measurement of muscle action potentials, e.g., electrical signals generated by muscles during their activity, e.g., using differential voltage meters. For example, during a muscle contraction, muscle cells can generate electrical activity in the form of muscle action potentials. These potentials can generate electrical currents that spread through the muscles and can be recorded by electrodes, e.g., on and / or under the skin. By measuring the differential voltage between the electrodes, information about the electrical activity of the muscle can be derived.

[0015] An "interference signal" can refer to an unwanted or unintended signal source and / or component that is present in a measurement system, for example, involuntarily and / or continuously, and / or that should be eliminated or at least reduced. This can be, for example, an electrical or electronic signal that affects the actual, intended signal being measured, particularly negatively, and can impair its quality, clarity, detectability, and / or accuracy. Interference signals can have various causes, such as electromagnetic interference, noise, signal distortion, and / or superposition with other signals.

[0016] A "useful signal," on the other hand, can refer to a desired signal and / or component that is to be captured, measured, detected, and / or determined in a measurement system, e.g., for analysis in order to obtain or derive further information. Useful signals can, for example, be overlaid by interference signals, which can make it difficult to determine and / or separate the useful signal itself.

[0017] The separation of useful and unwanted signals can refer to the process of separating, differentiating, and / or dividing the desired useful signal from the unwanted interference signals. Through this separation, a portion of the interference signals can be eliminated and / or at least reduced, for example, essentially completely.

[0018] A first, second, third, fourth, etc. "signal" can be understood as a physical quantity that comprises one or more pieces of information, e.g., an amplitude that indicates, for example, a signal strength, a frequency that indicates, for example, a signal periodicity, a phase that indicates, for example, a temporal shift, as well as a duration and / or a shape. The signal can also comprise one or more components, for example, a useful signal, in particular a first EMG signal component, and an interference signal, in particular a first EMG interference component.

[0019] An “EMG signal component” can refer to the desired electrical activity, e.g. generated by the muscles of a first muscle group, and include information about the muscle activity, such as contraction, relaxation and / or movement patterns, etc. The EMG signal component can therefore be understood as the useful signal that is to be recorded and / or analyzed in the EMG measurement. This could also be referred to as the EMG useful component or EMG useful signal component. An “EMG noise component,” on the other hand, can refer to unwanted noise or noise that is superimposed on the EMG signal component. This noise component can have various causes, such as electromagnetic interference, ambient noise, signal distortion due to electrode placement, unwanted muscle activity in neighboring muscles and / or other sources, e.g. other muscle groups nearby.An example of a noise component is an electrocardiogram (ECG) signal.

[0020] A signal detected by a first sensor device can be called the first signal, and a signal detected by a second sensor device can be called the second signal, and so on. The first signal can differ from the second signal, for example, because the first sensor device measures the first signal at a different position than the second sensor device. The first and second signals can be spatially resolved by the first and second sensor devices, respectively, and in particular, detected independently of each other (e.g., spatially and / or temporally), especially differentially, for example, in a specific direction, orientation, and / or along a specific axis.

[0021] The first sensor device and the second sensor device can preferably be mounted on a, in particular the same, muscle group, for example a first muscle group, preferably geometrically above the muscle or muscle group under consideration, e.g. on an overlying skin surface (e.g. non-invasively).

[0022] A first signal may include a first EMG signal component and a first EMG noise component, and a second signal may include a second EMG signal component and a second EMG noise component.

[0023] The first EMG signal component can differ from the second EMG signal component, in particular at least partially. For example, the first EMG signal component can differ from the second EMG signal component with regard to a signal curve, in particular a temporal one, in particular a voltage curve. However, the first EMG signal component and the second EMG signal component can comprise a substantially identical information content (e.g. same onset of the activity, same frequency, etc.), in particular a substantially identical information content with regard to myoelectric activity, or a substantially identical distribution of the myoelectric activity of the first muscle group. Mathematically speaking, the first EMG signal component and the second EMG signal component can be two statistically independent measurement variables, e.g. with the same distribution, which are, for example, not correlated.This is achieved, for example, in that the first EMG signal component and the second EMG signal component each measure slightly different portions and / or muscle fibers, for example of the same muscle, which can result, for example, from the independent positioning and / or arrangement of the first and second sensor devices.

[0024] A "sensor device" can refer to a device, measuring setup, detector, or instrument that can capture, detect, record, analyze, receive, record, and / or measure physical and / or chemical quantities and / or convert these quantities into electrical signals, e.g., for transmission and / or further analysis. A sensor device, for example, the first sensor device and / or the second sensor device, can each comprise at least two electrodes, e.g., for providing a first, in particular differential, measuring channel and a second, in particular differential, measuring channel. The electrodes can be surface electrodes and / or needle electrodes.

[0025] The first sensor device can be arranged at a distance from the second sensor device, e.g., on a first muscle group, wherein the distance can depend on the type and / or size of the first muscle group. For example, a large muscle group, such as the diaphragm, e.g., in an adult, allows a distance of approximately 30 cm (or less / more). Another muscle group, e.g., in the shoulder, e.g., in children, can only allow a distance of approximately 5 cm (or less / more). The distance can therefore depend on the anatomy, the type of muscle group, the conditions on the skin surface, and / or the person (e.g., subject) being examined (e.g., size, age, etc.).

[0026] According to the method according to the invention, a "combined signal" is determined based on the first signal and the second signal, in particular for suppressing the first and / or second EMG interference component. A "combined signal" can be understood as a combination, merging, and / or superimposing of the first signal with the second signal, or vice versa. In particular, the determination can comprise a separation of the first and / or second EMG interference component, wherein the separation is based on a subtraction of the first and second signals. For example, the first signal can be subtracted, deducted, and / or removed from the second signal, or vice versa, in order to obtain or determine the combined signal.In particular, by subtracting the first from the second signal, or vice versa, both the first and the second EMG noise components may substantially disappear, for example because they are substantially identical.

[0027] The method according to the invention can optionally comprise visualizing the combined signal (or several signals), in particular an origin of the combined signal (or several signals), wherein the visualization can in particular be a spatial and / or temporal visualization by means of a heat map. By means of a heat map, for example, data, information, signals, etc. can be displayed on a map and / or a spatial diagram, wherein different values, sizes and / or intensities can be visualized by colors. The data, information, signals and / or areas can be displayed on the map using a color scale, wherein, for example, higher values ​​and / or intensities can be represented by warmer colors such as red or orange and lower values ​​can be represented by cooler colors such as blue or green.A heatmap can make it possible to display or identify spatial and / or temporal patterns, progressions, trends, areas and / or differences in the data, information, signals.

[0028] The method according to the invention can further comprise: adapting signal amplitudes, in particular voltage amplitudes, of the first EMG interference component and signal amplitudes, in particular voltage amplitudes, of the second EMG interference component, in particular such that the signal amplitudes, in particular the voltage amplitudes, of the first EMG interference component substantially correspond to the signal amplitudes, in particular the voltage amplitudes, of the second EMG interference component. As already described above, the first EMG interference component and the second EMG interference component are substantially identical. However, minor deviations, differences and / or discrepancies can be compensated for by means of the adaptation, e.g. to ensure that the EMG interference components substantially disappear when the signals are combined, e.g. during subtraction.

[0029] The adaptation or matching can also be referred to as normalization. The normalization can be carried out using various calculation rules, for example by forming the ratio of the maximum signal amplitudes of the EMG noise components and / or generally by statistical estimation methods such as regression and / or adaptive filters. The adaptation can ensure that the first EMG noise component essentially corresponds to the second EMG noise component, whereby the latter disappears, for example when the combined signal is determined, for example because their values, in particular their amplitudes, are more closely matched to one another. This can, for example, improve the accuracy and / or the resulting or combined signal can be determined more clearly. However, the adaptation is optional.

[0030] The adjustment can be dynamic and / or continuous (also multiple times or repeatedly), especially during the acquisition of the first and second signals and / or in time before the determination of the combined signal.

[0031] The first EMG interference component and / or the second EMG interference component can comprise an electrocardiogram, ECG, signal, in particular an ECG voltage signal. The first EMG interference component and / or the second EMG interference component can be caused by and / or originate from the same source, e.g., from a heart muscle. This can also be referred to as the first source. In contrast, the EMG signal components that are detected, for example, on a first muscle group can be understood as two, in particular different, or independent sources. This can result, for example, from the independent positioning and / or arrangement of the first and second sensor devices on the first muscle group, e.g., geometrically above it on the skin (e.g., non-invasively).

[0032] The method according to the invention may further comprise: attaching the first sensor device and / or the second sensor device -- at different positions of the first muscle group, particularly adjacent, wherein the first muscle group particularly comprises respiratory muscles, preferably a diaphragm; and / or -- at a substantially identical distance to a second muscle group, the second muscle group being different from the first muscle group, the second muscle group comprising in particular cardiac muscles.

[0033] At different positions and / or adjacent can mean, for example, equidistant. For example, the electrodes of the first sensor array and the electrodes of the second sensor array can be arranged at equal distances from one another, e.g., a distance of 1 cm from one another or even more or less. If multiple sensor arrays are used, they can also be arranged at equal distances from one another, for example, at a distance that may depend on the type and / or size of the muscle group, as described above.

[0034] A "substantially identical distance to a second muscle group" can be understood as meaning that the first and second sensor devices are arranged such that a distance to the second muscle group is substantially equal or identical and / or a distance between the sensor devices is negligible in relation thereto. For example, the first sensor device and / or the second sensor device can be arranged, placed and / or attached in relation to one another such that they define an axis, wherein the axis points substantially in the direction of the second muscle group, e.g., such that the sensor devices are arranged or attached one below the other, one behind the other and / or one after the other, pointing in the direction of the heart muscle. Even if the first sensor device in this example is on this axis, then above, e.g.closer to the heart muscle than the second sensor device, or vice versa, this can be understood as a "substantially identical distance" since the distance between the sensor devices is correspondingly smaller and therefore negligible in comparison to the distance and / or distance to the second muscle group, e.g. to the heart muscle. It should be noted, however, that the arrangement along a specific axis, e.g. pointing in the direction of the heart muscle, is merely a preferred arrangement, i.e. optional, since particularly good results / measurements can be achieved with such an arrangement. Other arrangements are therefore also possible and likewise lead to good results.

[0035] The method according to the invention can be implemented using two sensor devices described herein, which can each comprise two electrodes. Optionally, however, a plurality of sensor devices can also be used and these can be applied, for example, to a plurality of muscles and / or a plurality of locations on the same muscle. For example, the first sensor device and the second sensor device can be copied and / or duplicated. This makes it possible, for example, to obtain a spatial and / or temporal resolution, for example 2D or 3D, of the activity, in particular the muscle activity. This can also be visualized using a heat map described herein, for example as an animation, in order to represent a spread and / or a direction of spread of the activity.

[0036] The method according to the invention may further comprise: Providing a duplicated sensor arrangement comprising a third sensor device for detecting a third signal and / or the fourth sensor device for detecting a fourth signal; Applying the duplicated sensor array to the first muscle group and / or at least one further muscle group different from the first muscle group.

[0037] As mentioned before, the first muscle group can be, for example, a diaphragm, and the third muscle group can be, for example, a shoulder muscle.

[0038] "Duplicated" can be understood as a repetition, copying, and / or duplication of the elements, components, and / or parts, e.g., of the first and / or second sensor devices and / or the method steps disclosed in this context, for example, that these can be repeated in the same way for the third and fourth sensor arrangements. It should therefore be understood that what is said herein with regard to the first / second sensor devices and / or the method according to the invention applies equally to the third and fourth sensor arrangements, as well as the method steps described in this regard, and vice versa.

[0039] A “duplicated sensor arrangement” can therefore represent a copy or duplicate of the first and second sensor devices and can comprise a third sensor device for detecting a third signal and / or the fourth sensor device for detecting a fourth signal.

[0040] The method according to the invention may further comprise: determining a further combined signal based on the third signal and the fourth signal. The method according to the invention may further comprise: visualizing the combined signal and the further combined signal, in particular using a heat map, in order to obtain a spatial and / or temporal resolution.

[0041] According to the second aspect, the invention relates to the use of the inventive method for monitoring at least one muscle group, in particular respiratory muscles, preferably for diaphragmatic monitoring, and / or for controlling a ventilator, and / or for controlling and / or monitoring prostheses and / or orthoses, and / or for motion analysis.

[0042] Possible uses and / or applications of the method according to the invention include one or more of: sports medicine applications, e.g. in the shoulder, including, for example, the investigation of training intensity and / or the detection of long-term trends in training. Based on this, over- / under-exertion could be detected, for example, using the EMG frequency spectrum. Applications in the direction of biofeedback would also be conceivable, e.g., a visualization of the training intensity for the athlete in real time and thus a direct adjustment of muscle activity (e.g., during a strength exercise). A further use and / or application would be in prosthetics, e.g., the direct control of hand prostheses. Here, the EMG of the forearm could be used to directly control the prosthesis. For example, a specific EMG activation could trigger a grasping movement of the prosthesis, etc.

[0043] According to the third aspect, the invention relates to a data processing device comprising means for carrying out the steps of the method according to the invention.

[0044] According to the fourth aspect, the invention further relates to a computer program product comprising instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the method according to the invention.

[0045] According to the fifth aspect, the invention further relates to a computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the steps of the method according to the invention.

[0046] As used herein, the terms “according to the invention,” “in accordance with the invention,” and the like are intended to refer to all described aspects and embodiments of the invention described and / or claimed herein.

[0047] The term "comprising" as used herein is to be construed to include both "including" and "consisting of," both meanings being specifically intended to disclose individually disclosed embodiments according to the present invention. Whenever the term "and / or" is used herein, the term "and / or" is to be understood as a specific disclosure of each of the two specified features or components with or without the other. For example, "A and / or B" is to be understood as a specific disclosure of each of (i) A, (ii) B, and (iii) A and B, as if each were listed individually herein. In the context of the present invention, the terms "about" and "approximately" respectively denote an interval of accuracy understood by those skilled in the art to nevertheless ensure the technical effect of the feature in question.The term typically indicates a deviation from the stated numerical value of ±20%, ±15%, ±10%, and, for example, ±5%. As one of ordinary skill in the art will appreciate, the specific such deviation for a numerical value for a given technical effect depends on the nature of the technical effect. For example, a natural or biological technical effect may generally have a greater such deviation than a man-made effect. Where an indefinite or definite article is used when referring to a singular noun, e.g., "a" or "an," this includes the plural of that noun, unless expressly stated otherwise herein.

[0048] Unless the context dictates otherwise, the descriptions and definitions of the features set forth above are not limited to any particular aspect or embodiment of the invention and apply equally to all described aspects and embodiments of the invention.

[0049] The application of the teachings of the present invention to a particular problem or setting and the incorporation of variations of the present invention or additional features thereto (such as further aspects and embodiments) are within the scope of a person of ordinary skill in the art consistent with the teachings of the invention contained herein.

[0050] All references, patents, patent publications and other publications cited herein are hereby incorporated in their entirety by reference into this disclosure. SHORT DESCRIPTION OF THE CHARACTERS

[0051] Embodiments of the invention will now be described with reference to the accompanying drawings. In order to understand the above-mentioned features of the present disclosure in detail, a more detailed description of the disclosure, briefly summarized above, can be obtained by reference to embodiments. The accompanying drawings relate to embodiments of the disclosure and are described below: Fig. 1 shows an arrangement according to the invention of a first and second sensor device mounted on a first muscle group, by means of which the method according to the invention can be carried out; Fig. Figure 2 shows exemplary measurement signals of the arrangement according to the invention. Fig. 1, in particular a first signal detected by the first sensor device and a second signal detected by the second sensor device; and Fig. 3 shows an exemplary combined signal based on the detected first signal and the second signal from Fig. 2.

[0052] In the following, the invention will be explained in more detail with reference to embodiments shown in the drawings, wherein in all drawings, essentially functionally identical elements have the same reference numerals.

[0053] The drawings are schematic drawings and are not to scale. Some elements in the drawings may have exaggerated dimensions to emphasize aspects of the present disclosure and / or for presentation clarity. For simplicity, identical reference numerals are used to identify identical elements commonly included in the drawings. It is contemplated that elements and features of one embodiment may be advantageously incorporated into other embodiments without further notice. In general, only the differences with respect to individual embodiments will be described.

[0054] Each embodiment serves to illustrate the disclosure and should not be understood as limiting the disclosure. Furthermore, features presented or described as part of one embodiment may be used in conjunction with other embodiments to create a further embodiment. It is intended that the description includes such modifications and variations.

[0055] Fig. Figure 1 shows an arrangement 100 according to the invention comprising a first sensor device 110, which may include a first electrode 110A and a second electrode 110B, and a second sensor device 120, which may also include a first electrode 120A and a second electrode 120B. The first sensor device 110 and the second sensor device 120 are arranged in Fig. 1 by an arrow, which can also be referred to as the measuring channel, or first measuring channel 110 and second measuring channel 120. As in Fig. As shown in Figure 1, the first sensor device 110 and the second sensor device 120 can be attached to a first muscle group 200, for example a diaphragm 200, e.g. geometrically and / or locally above it, for example on the skin (e.g. non-invasively).

[0056] Optionally, a duplicated sensor arrangement 130, 140 can be provided, comprising a third sensor device 130 for detecting a third signal and / or a fourth sensor device 140 for detecting a fourth signal. Fig. 1, the duplicated sensor arrangement 130, 140 is also mounted on the first muscle group 200, for example, at a distance from the first sensor device 110 and the second sensor device 120, wherein this distance may depend on the type and / or size of the muscle. Alternatively or additionally, the duplicated sensor arrangement 130, 140 may also be mounted on at least one further muscle group (not shown) that differs from the first muscle group 200. The third sensor device 130 and / or the fourth sensor device 140 may also each comprise two electrodes 130A-B, 140AB, which for reasons of clarity Fig. 1 are not provided with reference numerals. It should be noted that the duplicated sensor arrangement, in particular the third and fourth sensor devices 130, 140, are optional.

[0057] As in Fig. As shown in Figure 1, the first sensor device 110 and / or the second sensor device 120 are arranged, positioned, and / or attached in relation to each other such that they define an axis, the axis pointing essentially in the direction of the second muscle group 300, i.e., towards the heart muscle. In other words, the first sensor device 110 and the second sensor device 120 are arranged in a line in the direction of the heart 300, i.e., as shown in Figure 1. Fig. As shown in Figure 1, the first sensor device 110 and / or the second sensor device 120 are arranged one above the other, one behind the other, and / or one after the other. As can be seen, the first sensor device 110 can thus be located closer to the heart muscle 300 than the second sensor device 120. However, the distance between the first and second sensor devices 110 and 120 and the heart muscle is smaller than the distance between them, making it negligible. Therefore, the sensor devices 110 and 120 can have essentially the same distance to the heart, or this can be defined and / or specified.

[0058] With the in Fig. 1, for example, a diaphragm activity of a diaphragm 200 can be detected, whereby other muscles and / or muscle groups can also be detected. The first sensor device 110 can therefore represent a first measuring channel 110, e.g. at a first location or position, and the second sensor device 120 a second measuring channel 120, e.g. at a second, in particular different and / or independent, location or position. As previously described, the high local sensitivity of the EMG signal can lead to the signal curves, in particular the temporal signal curves of the EMG signal components, e.g.the first EMG signal component, which is detected by means of the first sensor device 110, and the second EMG signal component, which is detected by means of the second sensor device 120, are different; however, they comprise a substantially identical information content, in particular a substantially identical information content with regard to a myoelectric activity, or a substantially identical distribution of the myoelectric activity of the first muscle group, e.g. therefore the same information with regard to the muscle contraction, e.g. of the diaphragm 200 during a breathing process.

[0059] Due to the previously described large, but almost identical distance, or spacing, in the direction of the heart 300, the first sensor device 110 and the second sensor device 120 are each superimposed by an essentially identical EMG interference component, in particular an ECG signal and / or an ECG signal component.

[0060] Mathematically, this can be expressed as follows: CH1a=EMG1a+ECG;CH1b=EMG1b+ECG; where CH 1a can stand for the first signal that can be detected with the first measuring channel 110 (“channel”) or the first sensor device 110 and CH 1b for the second signal, which can be detected by the second measuring channel 120 (“channel”) or the second sensor device 120. The first signal can be a first EMG signal component EMG 1a and the second signal comprises a second EMG signal component EMG 1b .

[0061] As shown by the indices1a and 1b As indicated, the first EMG signal component EMG 1a from the second EMG signal component EMG 1b differ, in particular at least partially. For example, the first EMG signal component EMG 1a from the second EMG signal component EMG 1b with respect to a signal curve, particularly a voltage curve, particularly a temporal one. The first EMG signal component EMG 1a and the second EMG signal component EMG 1b However, they can contain essentially identical information (e.g., same onset of activity, same frequency, etc.), in particular essentially identical information regarding myoelectric activity, or essentially identical distribution of the myoelectric activity of the first muscle group. Mathematically speaking, the first EMG signal component can be EMG 1aand the second EMG signal component EMG 1b This involves two statistically independent measurement variables, e.g., with the same distribution, which are, for example, uncorrelated. This is achieved, for example, by having the first EMG signal component and the second EMG signal component each measure slightly different proportions and / or muscle fibers, for example, of the same muscle, which can result, for example, from the independent positioning and / or arrangement of the first and second sensor devices 110, 120.

[0062] As further apparent from formula (1), ECG can stand for the first EMG interference component and / or the second EMG interference component, which in this example comprises an electrocardiogram, ECG, signal, in particular an ECG voltage signal, wherein in particular the first EMG interference component and / or the second EMG interference component are caused and / or emanate from a same source, in particular from the heart muscle 300. As shown in formula 1, the first EMG interference component and the second EMG interference component are substantially identical, wherein additionally and optionally an adaptation or normalization described herein can be applied, for example in order to coordinate the EMG interference components more precisely with one another.

[0063] According to the invention, on the basis of the first signal CH 1a and the second signal CH 1b a combined signal CH kdetermined, for example, to suppress the first and / or second EMG noise component (e.g., ECG). Mathematically, this can be achieved, for example, by subtraction: CHk=CH1b−CH1a=(EMG1b+EKG)−(EMG1a+EKG) where CH k can represent the determined combined signal. It is clear that alternatively the calculation rule CH 1a - CH 1b could be applied.

[0064] It should also be clear that when using a duplicated sensor arrangement, another combined signal CH k2 which can have the following form: CHk2=CH2b−CH2a=(EMG2b+EKG)−(EMG2a+EKG) where CH 2a can stand for the third signal that can be detected with the third measuring channel 130 (“channel”) or the third sensor device 130 and CH 2bfor the fourth signal, which can be detected by the fourth measuring channel 140 ("channel") or the fourth sensor device 140. The third signal can comprise a third EMG signal component EMG", and the fourth signal can comprise a fourth EMG signal component EMG 2b etc. From these signals, another combined signal CH can then be generated. k2 within the meaning of the invention, e.g., by subtraction. As already mentioned, the statements made regarding the method according to the invention and / or regarding the first and second sensor devices 110, 120 apply here.

[0065] As already mentioned, depending on the measurement setup, it may be useful to perform a (dynamic) normalization of the measurement channels before subtraction, so that the ECG signal components actually have the same amplitude, for example. Because the EMG noise components of the first signal and the second signal are essentially identical, the following combined signal results: CHk=EMG1b−EMG1a

[0066] In the combined signal, the ECG noise component can be suppressed, whereby the signal CH k only the EMG signal components EMG 1a and EMG 1b This allows useful and interference signals in the EMG measurement in an electrically active region of muscles, for example, on the diaphragm 200, to be separated and / or isolated, or EMG interference components to be suppressed.

[0067] Fig. Figure 2 shows an example of a first signal CH 1a= EMG 1a + ECG and an exemplary second signal CH 1b = EMG 1b + ECG, which can be done using the arrangement of Fig. 1. The signal can be recorded, with the X-axis representing time in seconds and the Y-axis representing signal strength in any unit, e.g., optionally a normalized signal strength, e.g., a voltage amplitude in mV. To clarify and better (visually) distinguish these two signals in one diagram, the first signal CH 1a with an offset, for example, to display the signals separately. In Fig. 2 is the offset for the first signal CH 1a 0.3, which makes the first signal CH 1a moves "upward" in the diagram. Without offset, however, these two signals would be superimposed, for example, at the same position.

[0068] As is evident in Fig. 2 can be seen, the first signal CH 1aand the second signal CH 1b EMG signal components 301-307 (only for the signal CH 1b marked, but also in the signal CH 1a present) and EMG interference components 310. The EMG signal components 301-307 in Fig. 2 represent a muscle activity, e.g. of the diaphragm 200, e.g. one or more breathing periods of a subject. In Fig. 2 are a total of 7 breathing periods 301-307 (see also Fig. 3) of the subject have been measured and / or displayed. The EMG signal components of the first signal CH 1a (not marked) and the second signal CH 1b 310-307 are each compared to the EMG interference components 310, e.g. the ECG signals or the Fig. 2, the R-waves 310 of the ECG components 310 are significantly smaller or weaker. Therefore, it is difficult and / or complex to accurately capture the EMG signal components 301-307 and / or to distinguish and / or separate them from the EMG noise components 310.

[0069] Fig. 3 shows a combined signal CH k according to the invention that on the basis of the first signal CH 1a and the second signal CH 1b , as in Fig. Figure 2 shows the result, where the x-axis represents time in seconds and the y-axis represents the signal strength in any unit, e.g., optionally a normalized signal strength, e.g., a voltage amplitude in mV. In particular, the combined signal CH k by subtracting the first and second signals CH 1a and CH 1b , e.g. according to formula (2a).

[0070] As regards Fig. 2, the combined signal CH k in Fig. 3 the myoelectric activity e.g. of the diaphragm 200 can be clearly seen, whereby all EMG interference components 310, e.g. the ECG signals 310 of the heart 300, are included in the combined signal CH k, eg due to subtraction, eg according to formula (2a). This allows the subject's 7 breathing periods 301-307 to be clearly identified, whereby these breathing periods 301-307, or rather their peaks in myoelectric activity resulting from the breathing process, are recorded in the combined signal CH k by means of dashed lines on one side, for clarification and clarity, in the diagram of Fig. 3 are highlighted.

[0071] Furthermore, it should be noted that combined measurement approaches, for example by using one or more duplicated sensor arrangements 130, 140 (see Fig. 1), as mentioned herein, further improves the signal-to-noise ratio. It also enables a spatial and / or temporal representation of the signal origin, allowing for attribution to the diaphragm and / or other muscle groups.

[0072] The features disclosed in the above description, the figures and the claims may be important both individually and in any combination for the realization of the invention in the various embodiments.

Claims

[1] Method for separating useful and interference signals in an electromyographic, EMG, measurement in an electrically active region of muscles and / or for suppressing interference signals in the EMG measurement, comprising the following steps: - detecting a first signal with at least one first sensor device on a first muscle group, wherein the first signal has a first EMG signal component and a first EMG interference component; - detecting a second signal with at least one second sensor device on the first muscle group, wherein the second signal has a second EMG signal component and a second EMG noise component; - Determining a combined signal based on the first signal and the second signal for suppressing the first and / or the second EMG interference component. [2] Method according to claim 1, wherein the first and second signals are each detected by means of the first sensor device and the second sensor device in a spatially resolved manner, in particular independently of one another, in particular differentially. [3] The method of any one of claims 1-2, wherein determining the combined signal comprises separating the first and / or second EMG noise component, the separation being based on subtracting the first and second signals. [4] Method according to any one of claims 1-3, further comprising: - optionally, visualizing the combined signal, in particular an origin of the combined signal, wherein the visualization is in particular a spatial visualization by means of a heat map; - Adjusting signal amplitudes, in particular voltage amplitudes, of the first EMG interference component and signal amplitudes, in particular voltage amplitudes, of the second EMG interference component, in particular such that the signal amplitudes, in particular the voltage amplitudes, of the first EMG interference component substantially correspond to the signal amplitudes, in particular the voltage amplitudes, of the second EMG interference component. [5] Method according to claim 4, wherein the adaptation takes place dynamically and / or continuously, in particular during the detection of the first and the second signal and / or prior to the determination of the combined signal. [6] Method according to one of claims 1-5, wherein - the first EMG interference component and / or the second EMG interference component comprises an electrocardiogram, ECG, signal, in particular an ECG voltage signal, wherein in particular the first EMG interference component and / or the second EMG interference component are caused and / or emanate from the same source. [7] Method according to any one of claims 1-6, further comprising: - Attaching the first sensor device and / or the second sensor device -- at different positions of the first muscle group, in particular adjacent, wherein the first muscle group comprises in particular respiratory muscles, preferably a diaphragm; and / or -- at a substantially identical distance to a second muscle group, the second muscle group being different from the first muscle group, the second muscle group comprising in particular cardiac muscles. [8] The method of claim 7, wherein the first sensor device and / or the second sensor device define an axis, the axis pointing substantially in the direction of the second muscle group. [9] A method according to any one of claims 7-8, further comprising: Providing a duplicated sensor arrangement comprising a third sensor device for detecting a third signal and / or the fourth sensor device for detecting a fourth signal; Applying the duplicated sensor array to the first muscle group and / or at least one further muscle group different from the first muscle group. [10] A method according to claim 9, comprising: Determining another combined signal based on the third signal and the fourth signal. [11] A method according to claim 10, comprising: Visualizing the combined signal and the further combined signal, in particular by means of a heat map, in order to obtain a spatial and / or temporal resolution. [12] Method according to one of claims 1-11, wherein - the first EMG signal component differs from the second EMG signal component, in particular with regard to a signal curve, in particular a temporal signal curve, in particular a voltage curve. [13] Method according to one of claims 1-12, wherein - the first EMG signal component and the second EMG signal component comprise a substantially identical information content, in particular a substantially identical information content with respect to a myoelectric activity, or comprise a substantially identical distribution of the myoelectric activity of the first muscle group. [14] Method according to one of claims 1-13, wherein the first sensor device is arranged at a distance from the second sensor device on the first muscle group, the distance depending on a type and / or a size of the first muscle group. [15] Method according to any one of claims 1-14, wherein - the first sensor device and / or the second sensor device each comprises at least two electrodes for providing a first differential measuring channel and a second differential measuring channel, wherein - the electrodes are surface electrodes and / or needle electrodes. [16] Use of a method according to one of claims 1-15 for monitoring at least one muscle group, in particular respiratory muscles, preferably for diaphragm monitoring, and / or for controlling a ventilator, and / or for controlling and / or monitoring prostheses and / or orthoses, and / or for movement analysis. [17] A data processing apparatus comprising means for carrying out the steps of the method according to any one of claims 1-16. [18] A computer program product comprising instructions which, when executed by a computer, cause the computer to carry out the steps of the method according to any one of claims 1-16. [19] A computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to perform the steps of the method according to any one of claims 1-16.

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