Multi-modal sensor for spasm monitoring and evaluation and evaluation method
By designing a multimodal epidermal sensor, combining triboelectric sensors and surface electromyography sensors, the problem that traditional evaluation methods are difficult to achieve quantitative evaluation is solved, and accurate and real-time evaluation of spasm levels is achieved, and detection accuracy and treatment effect are improved.
Patent Information
- Application Number
- CN202510272542.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-10
- Publication Date
- 2025-06-13
AI Technical Summary
The traditional spasmodic evaluation method lacks the discussion of multimodal information on the neuromuscular function of the muscle group, making it difficult to achieve quantitative assessment of spasmodic phenomenon.
A multimodal epidermal sensor is designed, combining triboelectric sensors and surface electromyography sensors to generate triboelectric signals and surface electromyography signals through muscles to evaluate spasm levels in real time.
It achieves accurate and real-time evaluation of spasm levels, improves the accuracy of spasm detection and evaluation of treatment effects, and has significant clinical and scientific research significance.
Smart Images
Figure CN120131003A_ABST
Abstract
Description
Technical Field
[0001] The present invention specifically relates to a multimodal sensor and an evaluation method for spasm monitoring and evaluation. Background Art
[0002] Spasticity is one of the most common complications of stroke, leading to abnormal movement patterns and severely affecting the daily activities of patients. Traditional spasm evaluation methods mainly rely on clinical observation and questionnaires, lacking quantitative evaluation of spastic phenomena. However, current quantitative evaluations of muscle spasm often only focus on a certain functional characteristic of a single muscle, lacking exploration of multimodal information on the rich biomechanical and bioelectrical characteristics of muscle groups. Therefore, designing a multimodal epidermal sensor to further study bioelectrical and biomechanical characteristics is of great significance for spasm quantitative evaluation and rehabilitation. Summary of the Invention
[0003] The purpose of the present invention is to provide a multimodal sensor and an evaluation method for spasm monitoring and evaluation, which can accurately and real-time evaluate the spasm level, has significant clinical and scientific research significance, and improves the accuracy of spasm detection and the evaluation of treatment effects.
[0004] The technical solution adopted by the present invention is as follows: A multimodal sensor for spasm monitoring and evaluation includes a packaging layer, an upper friction layer, a spacer layer, a lower friction layer, an interdigital electrode layer, and an adhesion layer arranged in sequence from top to bottom; the packaging layer is used to package the upper friction layer (i.e., for packaging friction layer A and friction layer B), the spacer layer is used to separate the upper friction layer and the lower friction layer, the middle of the spacer layer is a hollow structure, when the muscle drives the skin to move, the upper and lower friction layers can contact and separate through the hollow structure of the spacer layer, the adhesion layer is used to closely adhere to the skin, and the surface electromyogram measurement end of the interdigital electrode layer contacts the skin through the adhesion layer; The upper friction layer includes friction layer A and friction layer B spliced left and right; the lower friction layer includes friction layer C, and friction layer A and friction layer B respectively form two single-electrode triboelectric sensors with friction layer C.
[0005] Preferably, the triboelectricity order of the friction layer materials of friction layer A, friction layer B, and friction layer C is: friction layer A < friction layer C < friction layer B; since the triboelectricity of friction layer A is less than that of friction layer C, friction layer A can form a pair of single-electrode TENG 1 with friction layer C; the triboelectricity of friction layer B is greater than that of friction layer C, so friction layer B can form a pair of single-electrode TENG 2 with friction layer C.
[0006] Preferably, the interdigital electrode layer includes a surface electromyogram electrode and a friction back electrode connected to each other, the friction back electrode is arranged on the bottom surface of the lower friction layer, below the upper friction layer, and the surface electromyogram electrode layer contacts the skin through the adhesion layer; Both the number of surface electromyogram electrodes and the number of friction back electrodes are two. The two surface electromyogram electrodes are arranged on both sides of the friction back electrodes. The two surface electromyogram electrodes are in contact with the skin through the adhesion layer. The two friction back electrodes are respectively connected to the two surface electromyogram electrodes and are respectively arranged below the friction layer A and the friction layer B.
[0007] Preferably, the upper friction layer is placed within the coverage range of the lower friction layer. Ventilation holes are provided on the side wall of the spacer layer for discharging the gas generated due to the contact and separation between the upper and lower friction layers.
[0008] Preferably, both the encapsulation layer and the adhesion layer are insulating flexible stretchable materials.
[0009] Preferably, the insulating flexible stretchable material is selected from any one of polydimethylsiloxane (PDMS), Ecoflex, polyurethane (PU), styrene-butadiene-styrene block copolymer (SBS), and styrene-ethylene-butene-styrene block copolymer (SEBS).
[0010] Preferably, the interdigital electrode layer is a conductive material; The conductive material of the interdigital electrode layer is selected from any one of silver nanowires, carbon nanotubes, and PEDOT:PSS conductive materials.
[0011] Preferably, the material of the friction layer A is silver nanowires or carbon nanotubes.
[0012] Preferably, the material of the friction layer B is a composite film formed by incorporating inorganic nanoparticles with high dielectric constant into a polymer matrix; The polymer matrix is polydimethylsiloxane PDMS or Ecoflex; The synthesized inorganic nanoparticles are strontium titanate coated with dopamine and surface loaded with silver particles (ST@PDA@Ag) or strontium barium titanate coated with dopamine and in-situ growth of silver on the dopamine layer (BST@PDA@Ag); The synthesized composite film is a PDMS / ST@PDA@Ag composite film or a PDMS / BST@PDA@Ag composite film.
[0013] Preferably, the preparation method of the friction layer B includes the following steps: Step 1, disperse strontium titanate ST or strontium barium titanate BST nanoparticles in a polydopamine PDA solution and stir; Step 2: Recover strontium titanate coated with dopamine ST@PDA or barium strontium titanate coated with dopamine BST@PDA nanoparticles through vacuum filtration, and wash the strontium titanate coated with dopamine ST@PDA or barium strontium titanate coated with dopamine BST@PDA nanoparticles with deionized water and absolute ethanol, then place them in a vacuum oven for drying to obtain strontium titanate coated with dopamine ST@PDA or barium strontium titanate coated with dopamine BST@PDA nanoparticles; Step 3: Take the dopamine-coated nanoparticles obtained in Step 2 above and add them to the silver ammonia solution for stirring in the dark; Step 4: After the above reaction is completed, add deionized water and ethanol in sequence and obtain ST@PDA@Ag or BST@PDA@Ag nanoparticles by centrifugation; Step 5: Finally, add the synthesized nanoparticles to the PDMS or Ecoflex matrix at a certain concentration to prepare a composite film.
[0014] A method for evaluating post-stroke spasticity using the multi-modal epidermal sensor as described above, comprising the following steps: Attach the multi-modal sensor to the leg muscle or arm muscle. For the triboelectric sensor, when the leg or arm moves, the muscle drives the skin to move, further causing the upper and lower friction layers to contact and separate through the hollow part of the spacer layer. At the same time, according to the different forces on the upper and lower friction layers caused by different movements, the friction area changes, and a voltage signal that changes with the muscle amplitude is output to the external circuit through the electrode, and the muscle spasm level is evaluated from the perspective of biomechanics; For the surface electromyography sensor, the human muscle spasm level is evaluated by sensing the potential change generated when the muscle fibers contract; when the leg or arm muscle contracts, the potential difference on the muscle fiber membrane changes, generating a weak bioelectric signal, that is, the surface electromyography signal (sEMG). These weak myoelectric signals are captured by the surface electromyography electrode layer in the interdigital electrode layer attached to the skin surface, thereby reflecting the activity state of the muscle, and further evaluating the level of muscle spasm from the perspective of bioelectric signals.
[0015] The specific process of evaluating the muscle spasm level from the perspectives of bioforce signals and bioelectric signals is as follows: S1: Use 2 of the multi-modal epidermal sensors (the reason for using two multi-modal epidermal sensors is to monitor the bioelectric signals and bioforce signals of a pair of antagonist muscles. For example: biceps brachii and triceps brachii, tibialis anterior muscle and gastrocnemius muscle), attach them to the corresponding muscle parts of the human leg or arm, and collect multi-channel signals of movements, including bioforce signals, that is, triboelectric signals, and bioelectric signals, that is, surface electromyography signals; S2: Extract signal features and use classification algorithms for training to establish corresponding training and recognition models (the model training process is as follows: fuse multi-modal information, train a self-supervised convolutional neural network based on the structure of an autoencoder and a multi-layer perceptron, and construct a lightweight low-training-cost disease classification model through transfer learning); S3: Based on the evaluation results of professional physicians on the spasm level of patients as the golden standard for model calibration, and at the same time use the established model above to identify and classify new multi-channel signals to quantitatively evaluate the spasm level of patients. The beneficial effects of the present invention are: In the present invention, the muscle drives the skin to move, so that the upper and lower friction layers come into contact and separate, generating friction. At the same time, according to the different forces on the upper and lower friction layers caused by different actions, the friction area changes, and a triboelectric signal that changes with the muscle amplitude is output to the external circuit through the interdigital electrode layer. The spasm level is evaluated from the perspective of biomechanics, and weak surface electromyographic signals are captured by the surface electromyographic signal measurement terminals in the interdigital electrode layer attached to the skin surface, so as to reflect the activity state of the muscle, and then the spasm level of the muscle is evaluated from the perspective of bioelectric signals; through the present invention, a multi-modal sensor is formed to measure the triboelectric signal and the surface electromyographic signal in real time, and then according to the triboelectric signal and the surface electromyographic signal, the spasm level can be accurately and real-time evaluated, which has significant clinical and scientific research significance, improves the accuracy of spasm detection and the evaluation of treatment effects, and is especially suitable for post-stroke spasm monitoring and evaluation. Description of the Drawings
[0016] Figure 1 It is a schematic structural diagram of a multi-modal epidermal sensor for spasm evaluation in an embodiment of the present invention.
[0017] Figure 2 It is a schematic working diagram of a multi-modal sensor for spasm monitoring and evaluation in an embodiment of the present invention.
[0018] Figure 3 It is a schematic working principle diagram of a triboelectric sensor in a multi-modal epidermal sensor for spasm evaluation during muscle contraction in an embodiment of the present invention.
[0019] Figure 4 It is a schematic working principle diagram of a triboelectric sensor in a multi-modal epidermal sensor for spasm evaluation during muscle relaxation in an embodiment of the present invention.
[0020] Figure 5 It is a schematic response diagram of the surface electromyographic signal of a multi-modal epidermal sensor for spasm evaluation under different hand grip forces in an embodiment of the present invention.
[0021] Figure 6It is a signal diagram of the triboelectric sensor of the multimodal epidermal sensor for spasm assessment in the embodiments of the present invention, which changes with the change of external pressure.
[0022] In the figure: 1 - encapsulation layer; 2 - friction layer A; 3 - friction layer B; 4 - spacer layer; 5 - friction layer C; 6 - interdigital electrode layer; 61 - surface electromyogram electrode; 62 - friction back electrode; 7 - adhesion layer. Specific embodiments
[0023] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0024] In the description of the present invention, it should be understood that if there are terms involved such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined.
[0025] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0026] Embodiment 1 A multi-modal sensor for spasm monitoring and evaluation, comprising a packaging layer 1, an upper friction layer, a spacer layer 4, a lower friction layer, an interdigital electrode layer 6 and an adhesion layer 7 arranged in sequence from top to bottom; the packaging layer 1 is used to package the upper friction layer (i.e., for packaging friction layer A and friction layer B), the spacer layer 4 is used to separate the upper friction layer and the lower friction layer, the upper friction layer and the lower friction layer have different electronegativities, the middle of the spacer layer is a hollow structure, when the muscle drives the skin to move, the upper and lower friction layers can contact and separate through the hollow structure of the spacer layer, the adhesion layer 7 is used to closely adhere to the skin, and the surface electromyogram signal measurement end of the interdigital electrode layer 6 contacts the skin through the adhesion layer 7; The upper friction layer includes friction layer A 2 and friction layer B 3 arranged on the same layer; the lower friction layer is friction layer C 5, and friction layer A and friction layer B respectively form two single-electrode triboelectric sensors with friction layer C; The electronegativity order of the friction layer materials of the friction layer A, friction layer B and friction layer C is: friction layer A < friction layer C < friction layer B; since the electronegativity of friction layer A is less than that of friction layer C, friction layer A can form a pair of single-electrode TENG 1 with friction layer C; the electronegativity of friction layer B is greater than that of friction layer C, so friction layer B can form a pair of single-electrode TENG 2 with friction layer C.
[0027] Furthermore, the interdigital electrode layer 6 includes two surface electromyogram electrodes 61 and two friction back electrodes 62, the friction back electrodes are arranged on the bottom surface of the lower friction layer, directly below the upper friction layer, and the surface electromyogram electrode layer contacts the skin through the adhesion layer 7 as the surface electromyogram signal measurement end.
[0028] The two friction back electrodes are respectively arranged directly below friction layer A 2 and friction layer B 3 as the back electrodes of the triboelectric sensor, the two surface electromyogram electrodes are respectively arranged on both sides of the friction back electrodes, the two surface electromyogram electrodes contact the skin through the adhesion layer 7, the two friction back electrodes are respectively connected to the two surface electromyogram electrodes to form two parallel branches, and the two surface electromyogram electrodes are respectively connected to an external circuit.
[0029] The external circuit is as Figure 2 shown, including two equivalent resistors 11, two equivalent capacitors 12 and a load resistor 13. One end of the load resistor 13 is connected to one end of an equivalent resistor 11 and one end of an equivalent capacitor 12, the other end of the load resistor 13 is connected to one end of the other equivalent resistor 11 and one end of the other equivalent capacitor 12, and the other ends of the two equivalent resistors 11 and the other ends of the two equivalent capacitors 12 are connected to the multi-modal epidermal sensor (the external circuit is an equivalent circuit, not really connecting resistors and capacitors, the human skin itself has contact impedance), and the triboelectric signals 15 and surface electromyogram signals 14 of the corresponding muscles are respectively monitored through the corresponding friction back electrodes and surface electromyogram electrodes.
[0030] As shown Figure 1 in the figure, the two surface electromyogram electrodes are rectangles arranged on both sides of the interdigital electrode layer 6. Two friction electrodes in the friction back electrode of the interdigital electrode layer 6 are joined together in the shape of the Yin and Yang fish of "Tai Chi" or joined together into a complete circle by two semi-circular shapes.
[0031] The friction layer A and the friction layer C form a pair of friction electrical sensors with single electrodes. The electrode of the friction layer C is a semi-circular friction electrode corresponding to the one below the friction layer C. Similarly, the friction layer B and the friction layer C form a pair of single electrode sensors, and the electrode of the friction layer C is also the other semi-circular friction electrode below. The two semi-circular friction electrodes are not electrically connected to each other.
[0032] The positions of the two surface electromyogram electrodes should satisfy that one is a measuring electrode and the other is a reference electrode. The pasting positions of the two surface electromyogram electrodes should be along the direction of the muscle fibers. Considering the overall size of the sensor, the surface electromyogram electrodes are placed on both sides of the back electrode of the friction layer of the friction electrical sensor.
[0033] Furthermore, the upper friction layer is placed within the coverage range of the lower friction layer. Ventilation holes are provided on the side wall of the spacer layer. The gas pressure generated when the upper and lower friction layers come into contact can be discharged through the ventilation holes.
[0034] Furthermore, the upper friction layer is circular, and the lower friction layer is square; the spacer layer is a non-closed circular ring, and the circular upper friction layer and the spacer layer are coaxially arranged.
[0035] The friction layer A and the friction layer B are spliced together. The friction layer A and the friction layer B are complementary and are spliced in the shape of the Yin and Yang fish of "Tai Chi" or spliced by two semi-circular shapes.
[0036] Furthermore, the materials of the encapsulation layer 1 and the adhesion layer are both insulating flexible stretchable materials.
[0037] Furthermore, the insulating flexible stretchable material is selected from any one of polydimethylsiloxane (PDMS), Ecoflex, polyurethane (PU), styrene-butadiene-styrene block copolymer (SBS), and styrene-ethylene-butene-styrene block copolymer (SEBS).
[0038] Furthermore, thermoplastic polyurethane (TPU) can be preferably used in polyurethane (PU).
[0039] Furthermore, the material of the interdigital electrode layer 6 is a conductive material; The conductive material of the interdigital electrode layer is selected from any one of silver nanowires, carbon nanotubes, and poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS) conductive materials.
[0040] Furthermore, the material of the adhesive layer 7 is a viscous material.
[0041] Furthermore, the material of the friction layer A is silver nanowires or carbon nanotubes, which serve as the positive electrode friction layer material.
[0042] Further, the material of the friction layer B is a composite film formed by incorporating inorganic nanoparticles with a high dielectric constant into a polymer matrix; The material of the polymer matrix is polydimethylsiloxane PDMS or Ecoflex; The synthesized inorganic nanoparticles are dopamine-coated strontium titanate with silver particles loaded on the surface (ST@PDA@Ag) or dopamine-coated barium strontium titanate with silver grown natively on the dopamine layer (BST@PDA@Ag); The synthesized composite membrane is PDMS / BST@PDA@Ag composite membrane or PDMS / BST@PDA@Ag composite membrane.
[0043] The preparation method of the friction layer B comprises the following steps: Step 1, dopamine hydrochloride (0.6 g) and tris(hydroxymethylaminomethane) hydrochloride (0.5 g) were mixed to prepare a polydopamine PDA solution (200 ml), and then the pH of the solution was adjusted to 8.5 with a sodium hydroxide solution (concentration: 0.1 mol / L); Step 2, dispersing strontium titanate ST or barium strontium titanate BST nanoparticles (6 g) in the above polydopamine PDA solution, and mechanically stirring at 30° C. for 18 hours; Step 3, recovering dopamine-coated strontium titanate ST@PDA or dopamine-coated barium strontium titanate BST@PDA nanoparticles by vacuum filtration, washing with deionized water and anhydrous ethanol for 3 times, and finally drying in a vacuum oven at 70° C. for 6 hours to obtain dopamine-coated strontium titanate ST@PDA or dopamine-coated barium strontium titanate BST@PDA nanoparticles; Step 4, prepare 30 ml of silver ammonia solution: slowly add ammonia water (28%) into a 0.1 mol / L silver nitrate solution, first produce a white precipitate of silver hydroxide AgOH, then as the ammonia water is continued to be added, the precipitate gradually dissolves until the solution is clear, and a fresh silver ammonia solution is obtained; Step 5, taking 1 g of the dopamine-coated nanoparticles obtained in the above step 2, adding it to the prepared silver ammonia solution and stirring it in the dark for 12 hours; Step 6, after the above reaction is completed, deionized water and ethanol are added in sequence and centrifuged to obtain silver particles loaded on the surface of dopamine-coated strontium titanate (ST@PDA@Ag) or silver particles loaded on the surface of dopamine-coated barium strontium titanate nanoparticles (BST@PDA@Ag); Step 7. Finally, add the synthesized nanoparticles prepared in Step 6 into the PDMS or Ecoflex matrix at a certain concentration to prepare a composite film, and explore the electrical output performance of the triboelectricity generated by the composite film at different doping concentrations.
[0044] In Step 7, the synthesized nanoparticles can be added into the PDMS or Ecoflex matrix at different concentrations in a certain gradient (such as a gradient concentration of 0%, 5%, 10%, 15%, 20%) to explore the optimal electrical output performance of the triboelectric sensor at different doping concentrations. For example, in this embodiment, the composite film is prepared at a doping concentration of 15%.
[0045] A method for evaluating post-stroke spasticity using the multi-modal epidermal sensor as described above includes the following steps: Attach the multi-modal sensor to the leg muscle or arm muscle. For the triboelectric sensor, when the leg or arm moves, the muscle drives the skin to move, which further causes the upper and lower friction layers to contact and separate through the hollow part of the spacer layer (the spacer layer is a non-closed hollow ring, and the upper and lower friction layers contact in the hollow part of the spacer layer), generating friction. At the same time, according to the different forces on the upper and lower friction layers caused by different leg or arm movements, the friction area changes. Based on the principles of triboelectrification and electrostatic induction, the upper and lower friction layers are made of two materials with a large difference in electronegativity, and a changing electric field will be generated when they contact and separate, and equal amounts of opposite charges will be induced on the corresponding friction back electrodes of the interdigital electrode layer 6. When the electric field changes, electrons will flow back and forth between the two electrodes; and a triboelectric signal that changes with the muscle amplitude is output to the external circuit, and the corresponding bioforce signal is monitored according to the change of the triboelectric signal, and then the muscle spasm level is evaluated from the perspective of biomechanics.
[0046] For the surface electromyography sensor on the leg or arm surface, the human muscle spasm level is evaluated by sensing the potential change generated when the muscle fibers contract; when the muscle contracts, the potential difference on the muscle fiber membrane changes, generating a weak bioelectric signal, that is, the surface electromyography signal (sEMG). The weak surface electromyography signal is captured by the surface electromyography electrodes in the interdigital electrode layer attached to the skin surface, so as to reflect the activity state of the muscle, and then the level of muscle spasm is evaluated from the perspective of bioelectric signals.
[0047] The specific process of evaluating the muscle spasm level from the perspectives of bioforce signals and bioelectric signals is as follows: S1: Two of the multi-modal epidermal sensors are used (the reason for using two multi-modal epidermal sensors is to monitor the bioelectric signals and biomechanical signals of a pair of antagonist muscles. For example, biceps brachii and triceps brachii, tibialis anterior muscle and gastrocnemius muscle). They are attached to the muscle part of the human calf to collect multi-channel signals of different movements such as plantar flexion and dorsiflexion of the foot, including biomechanical signals, i.e., triboelectric signals, and bioelectric signals, i.e., surface electromyography signals). S2: Extract signal features and use classification algorithms for training to establish a corresponding training and recognition model (the model training process is as follows: fuse multi-modal information, train a self-supervised convolutional neural network based on the structure of an autoencoder and a multi-layer perceptron, and construct a lightweight and low-training-cost disease classification model through transfer learning). S3: Based on the evaluation results of professional physicians on the patient's spasm level as the gold standard for model calibration, and at the same time use the established model to identify and classify new multi-channel signals to quantitatively evaluate the patient's spasm level.
[0048] Example 2 On the basis of Example 1, the parameters of the encapsulation layer, upper friction layer, spacer layer, lower friction layer, and interdigital electrode layer are defined, and the performance of Example 2 after definition is better.
[0049] The encapsulation layer of the sensor is circular with a radius of 8 mm. Friction layer A and friction layer B are complementary, each being half of a circle with a radius of 8 mm, and together they form a "Bagua" shape. The spacer is a non-closed ring with a radius of 8 mm. Friction layer C is approximately a rectangle with a size of 54 mm × 30 mm. The length and width of the surface electromyography electrode are 20 mm × 10 mm. The overall shape of the adhesion layer is similar to that of friction layer C, and there is a hollow in the middle to expose two electromyography electrodes. The size of the hollow rectangle is a rectangle with a length of 20 mm and a width of 10 mm. The overall shape of the multi-modal sensor is round at the top and square at the bottom. The geometric centers of each of the above layers are located on the same axis.
[0050] It has two working modes: It means that multi-modal sensing can be achieved. It can either monitor the biomechanical signals of skin deformation during muscle contraction through triboelectric signals, or monitor electromyography signals through surface electromyography sensors.
[0051] For the triboelectric sensor, the electronegativity of friction layer A is less than that of friction layer C, and the two form a single-electrode triboelectric sensor. Similarly, the electronegativity of friction layer B is greater than that of friction layer C, and the two form another single-electrode triboelectric sensor. The friction back electrode in the interdigital electrode layer (6) serves as the back electrode of the triboelectric sensor.
[0052] For a surface electromyogram sensor, the interdigital electrode layer (6) consists of two surface electromyogram electrodes, which are made of a pair of rectangular conductive and stretchable materials with a length of 20 mm and a width of 10 mm. When the muscle contracts, the potential difference on the muscle fiber membrane changes, and this change is captured.
[0053] The triboelectric electrodes of the two triboelectric sensors are in a semi-circular structure and are connected in parallel with the surface electromyogram electrodes.
[0054] The working principle of the present invention is as follows: Figure 1 As shown in the figure, a multimodal sensor for spasm monitoring and evaluation includes a packaging layer 1, a friction layer A 2, a friction layer B 3, a spacer layer 4, a friction layer C 5, an interdigital electrode layer 6, and an adhesion layer 7. Among them, the friction layer A 2 and the friction layer B 3 are each half of a circle, and together with the friction layer C 5, they form two single-electrode triboelectric sensors respectively. The packaging layer 1 is used to package the friction layer A and the friction layer B. The spacer layer 4 is coaxial with the circle formed by the friction layer A and the friction layer B, separating the friction layer A, the friction layer B, and the friction layer C, ensuring that they can quickly contact and separate when sensing skin deformation, and they are in a separated state under normal conditions. The interdigital electrode layer 6 is deposited on the other side of the friction layer C, and finally, an adhesion layer 7 is coated on the other side of the interdigital electrode layer 6, sticking tightly to the surface of the human skin.
[0055] The muscles related to lower limb movements described above are selected from a pair of antagonist muscles, namely the tibialis anterior muscle and the gastrocnemius muscle, as the signal source muscles.
[0056] The sensor is attached to the skin of the human calf. When there is no movement in the leg, the upper and lower friction layers of the sensor are in a separated state. When leg movements occur (such as plantar flexion, dorsiflexion, etc.), the upper and lower friction layers undergo relative friction and separation. The upper and lower friction layers are made of different materials, with a difference in triboelectric electrode sequence. Under the premise that the conditions of contact and separation between the upper and lower friction layers are the same, the greater the difference in triboelectric electrode sequence, the greater the amplitude of the output electrical signal.
[0057] The adhesion layer enables the multimodal epidermal sensor to be firmly attached to the surface of the human skin.
[0058] For the schematic diagram of the mechanism of synchronously collecting EMG signals and triboelectric signals of the multimodal sensor for spasm monitoring and evaluation of the present invention, see Figure 2Under the action of the adhesion layer 7, the multimodal epidermal sensor can be tightly adhered to the skin surface and deform synchronously with the skin. Therefore, when muscle movement causes skin deformation, the sensor will also be driven to deform, generating triboelectric signals. In addition, the human skin and muscle tissues in contact with the electrodes are not insulators, but form a "load" composed of a parallel connection of resistance and capacitance. Therefore, the triboelectric signals collected by the ADC module are not open-circuit voltages, but "load voltages". Since a load is connected, its voltage cannot be maintained, so the waveform is approximately a short-circuit current, that is, a peak is generated as the action progresses, and then a peak in the opposite direction is generated as the action resumes, and finally returns to near zero. At the same time, sEMG signals are generated during the active contraction and passive relaxation of muscles, and these signals will also be captured by the electrode layer of the sensor.
[0059] For the working principle of the triboelectric sensor in the multimodal epidermal sensor for post-stroke spasticity assessment of the present invention, see Figure 3 and Figure 4 As Figure 3 shown, when the muscle contracts, the friction layers of the triboelectric sensor gradually come into contact. Based on the principles of triboelectrification and electrostatic induction, materials with weak electronegativity are prone to losing electrons, while materials with strong electronegativity are prone to gaining electrons, and equal amounts of opposite charges are induced on the back electrode. At the same time, a changing electric field is generated to drive electrons to flow back and forth in the external circuit, making the friction layer material A carry a positive charge and the friction layer material B carry a negative charge. As Figure 4 shown, when the muscle relaxes, the friction layers of the triboelectric sensor gradually separate, and a certain potential difference is generated between the two electrodes, driving electrons to flow from the right electrode to the left electrode, generating induced charges.
[0060] Figure 5 This is the surface electromyogram signal in the multimodal epidermal sensor proposed by the present invention, and the electromyogram signal response under different hand grip forces.
[0061] Figure 6 This is the signal diagram of the triboelectric sensor in the multimodal epidermal sensor proposed by the present invention changing with external pressure. When an external pressure is applied to the multimodal epidermal sensor, the multimodal epidermal sensor generates an electrical signal, and when the external pressure is removed, the signal of the multimodal epidermal sensor also returns to the resting potential, indicating that the sensor also has good sensing performance for external pressure.
[0062] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.
[0063] It should be understood that those of ordinary skill in the art can make improvements or transformations according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.
Claims
1. A multimodal sensor for monitoring and evaluating spasticity, characterized in that: The invention comprises an encapsulation layer (1), an upper friction layer, a spacing layer (4), a lower friction layer, an interdigital electrode layer (6) and an adhesive layer (7) which are arranged in sequence from top to bottom; the encapsulation layer (1) is used to encapsulate the upper friction layer; the spacing layer (4) is used to separate the upper friction layer from the lower friction layer; the upper friction layer and the lower friction layer have different electronegativity; the middle of the spacing layer is a hollow structure; the contraction and relaxation of muscles cause the upper and lower friction layers to contact and separate through the hollow structure of the spacing layer; the adhesive layer (7) is used to fit closely to the skin; the surface electromyography signal measuring end of the interdigital electrode layer (6) contacts the skin through the adhesive layer (7).
2. The multimodal sensor for monitoring and evaluating spasticity according to claim 1, characterized in that: The upper friction layer includes a friction layer A (2) and a friction layer B (3) arranged on the same layer; the lower friction layer includes a friction layer C (5), and the friction layer A and the friction layer B respectively form two single-electrode triboelectric sensors with the friction layer C; The order of electronegativity of the friction layer materials of the friction layer A, friction layer B, and friction layer C is: friction layer A < friction layer C < friction layer B; since the electronegativity of the friction layer A is less than that of the friction layer C, the friction layer A can form a pair of single-electrode TENG 1 with the friction layer C; the electronegativity of the friction layer B is greater than that of the friction layer C, so the friction layer B can form a pair of single-electrode TENG 2 with the friction layer C.
3. The multimodal sensor for monitoring and evaluating spasticity according to claim 1, characterized in that: The interdigital electrode layer (6) comprises a surface electromyographic electrode and a friction back electrode. The friction back electrode is arranged on the bottom surface of the lower friction layer and is located below the upper friction layer. The surface electromyographic electrode contacts the skin through the adhesive layer (7).
4. The multimodal sensor for monitoring and evaluating spasticity according to claim 3, characterized in that: The upper friction layer includes a friction layer A (2) and a friction layer B (3) arranged on the same layer; the number of surface electromyographic electrodes and the number of friction back electrodes are both two, and the two friction back electrodes are arranged respectively below the friction layer A (2) and the friction layer B (3), the two friction back electrodes are respectively connected to the two surface electromyographic electrodes, and the two surface electromyographic electrodes are respectively connected to the external circuit.
5. The multimodal sensor for monitoring and evaluating spasticity according to claim 1, characterized in that: The upper friction layer is placed within the coverage of the lower friction layer, and a vent hole is provided on the side wall of the spacing layer for discharging the gas generated by the contact and separation between the upper and lower friction layers.
6. The multimodal sensor for monitoring and evaluating spasticity according to claim 1, characterized in that: The materials of the encapsulation layer (1) and the adhesive layer are insulating, flexible and stretchable materials; The insulating flexible stretchable material is selected from any one of polydimethylsiloxane (PDMS), Ecoflex, polyurethane, styrene-butadiene-styrene block copolymer, and styrene-ethylene-butylene-styrene block copolymer.
7. The multimodal sensor for monitoring and evaluating spasticity according to claim 1, characterized in that: The material of the interdigital electrode layer (6) is a conductive material; The conductive material of the interdigital electrode layer is selected from any one of silver nanowires, carbon nanotubes, and PEDOT:PSS conductive materials.
8. The multimodal sensor for monitoring and evaluating spasticity according to claim 2, characterized in that: The material of the friction layer A is silver nanowires or carbon nanotubes; The material of the friction layer B is a composite film formed by incorporating inorganic nanoparticles with a high dielectric constant into a polymer matrix.
9. The multimodal sensor for monitoring and evaluating spasticity according to claim 8, characterized in that: The material of the polymer matrix is polydimethylsiloxane PDMS or Ecoflex; The synthesized inorganic nanoparticles are dopamine-coated strontium titanate with silver particles loaded on the surface (ST@PDA@Ag) or dopamine-coated barium strontium titanate with silver grown natively on the dopamine layer (BST@PDA@Ag); The synthesized composite membrane is PDMS / ST@PDA@Ag composite membrane or PDMS / BST@PDA@Ag composite membrane.
10. A method for evaluating post-stroke spasticity using the multimodal epidermal sensor according to any one of claims 1 to 9, characterized in that: The following steps are involved: The multimodal sensor is adhered to the leg muscles or arm muscles. When the leg or arm moves, the muscles drive the skin to move, thereby further causing the upper and lower friction layers to contact and separate through the hollow part of the spacing layer. At the same time, the friction area changes according to the difference in the magnitude of the force on the upper and lower friction layers caused by different movements. Based on the principles of friction electrification and electrostatic induction, the upper and lower friction layers are two materials with a large difference in electronegativity. When they contact and separate, a changing electric field is generated, and equal amounts of heterogeneous charges are induced on the interdigital electrode layer (6). When the electric field changes, electrons flow back and forth between the two electrodes. A friction electric signal that changes with the muscle amplitude is output to an external circuit, and the muscle spasm level is evaluated from a biomechanical perspective based on the change in the friction electric signal. When the leg or arm muscles contract, the potential difference on the muscle fiber membrane changes, generating a weak bioelectric signal, namely a surface electromyographic signal. The weak surface electromyographic signal is captured by the surface electromyographic signal measuring end in the interdigital electrode layer attached to the skin surface, thereby reflecting the activity state of the muscle and evaluating the degree of muscle spasm from the perspective of bioelectric signals.