Closed-loop percutaneous spinal cord electrical stimulation analgesia system and method based on physiological feedback

Abstract

The invention discloses a closed-loop percutaneous spinal cord electrical stimulation analgesia system and method based on physiological feedback, and belongs to the field of noninvasive electrical stimulation analgesia technologies and stimulation control systems thereof. The system comprises an electrode patch, a flexible substrate of which is provided with at least one pair of electrode units in an integrated manner, and the electrode patch is used for being attached to a corresponding spinal cord segment area of the body surface of a subject; the physiological signal acquisition module is used for acquiring a multi-modal physiological signal of a subject in real time; the stimulator is electrically connected with the electrode patch and used for generating and outputting electrical stimulation signals to at least one pair of electrode units of the electrode patch; the control module is connected with the physiological signal acquisition module and the stimulator and is used for evaluating the pain state of the subject based on the physiological signals acquired by the physiological signal acquisition module; and according to the evaluation result, generating a control instruction to perform closed-loop adjustment on the output state of the stimulator. According to the system, objective feedback is introduced, adaptability is improved, noninvasive individualization is achieved, operation is easy and convenient, and closed-loop automatic control over monitoring, analysis and adjustment is achieved.

Description

Technical Field

[0001] This invention relates to the fields of biomedical engineering and rehabilitation medicine, and in particular to a closed-loop percutaneous spinal cord electrical stimulation analgesia system and method based on physiological feedback, for optimizing and adjusting analgesia protocols. Background Technology

[0002] Pain is one of the most common and challenging health problems in clinical practice, widely present in various disease states such as low back pain, neuropathic pain, postoperative pain, and chronic pain. Long-term or recurrent pain not only severely impacts patients' quality of life and functional status but also triggers psychological problems such as anxiety and depression, resulting in a significant social and economic burden. Currently, pain treatment mainly includes drug therapy, physical therapy, and interventional neuromodulation. Among these, drug therapy, especially opioids, while able to relieve pain to some extent, is prone to tolerance, dependence, and various adverse reactions with long-term use, limiting its clinical application.

[0003] Spinal cord stimulation (SCS), a neuromodulation technique, modulates pain signal transmission pathways by applying electrical stimulation to relevant segments of the spinal cord and has been widely used to treat various intractable pain conditions. However, traditional implantable SCS systems typically require surgical implantation of electrodes and stimulators, which is highly invasive, expensive, and carries significant surgical risks, limiting their widespread application in some patients. In recent years, percutaneous spinal cord stimulation (TSCS) has gained attention as a non-invasive or minimally invasive alternative. It stimulates spinal cord segments via surface electrodes and has shown potential in analgesia and functional modulation.

[0004] Most existing percutaneous spinal cord stimulation (PCL) systems employ an open-loop stimulation mode with preset parameters. This means that the stimulation frequency, intensity, and duration are typically set by the operator based on experience or patient feedback, lacking dynamic monitoring and adjustment of the individual's real-time physiological state and pain changes during stimulation. This open-loop control method struggles to address the dynamic changes in pain status between different individuals and within the same individual at different times, easily leading to insufficient stimulation resulting in limited analgesia, or excessive stimulation causing discomfort or even adverse reactions. Furthermore, relying on the patient's subjective pain score for adjustment suffers from high subjectivity, poor real-time performance, and complex operational procedures.

[0005] With the development of physiological signal acquisition and intelligent control technologies, objective physiological indicators such as electromyography (EMG), electroencephalography (EEG), and electrocardiography (ECG) are considered to be closely related to pain perception and autonomic nervous activity, and can be used to reflect an individual's pain state and stress level. However, current technologies lack a closed-loop analgesia system that can introduce multimodal physiological signals into the percutaneous spinal cord stimulation modulation process in real time and automatically adjust stimulation parameters or stimulation state based on physiological feedback.

[0006] Therefore, there is an urgent need for a closed-loop analgesia system and method that can combine objective physiological feedback information to perform real-time and individualized control of percutaneous spinal cord stimulation, so as to improve the stability and safety of analgesia, reduce reliance on human experience and subjective assessment, simplify clinical operation procedures, and thus expand the application value of percutaneous spinal cord stimulation in the field of pain treatment. Summary of the Invention

[0007] The purpose of this invention is to propose a closed-loop percutaneous spinal cord electrical stimulation analgesia system and method based on physiological feedback, which can solve the problems of existing electrical stimulation systems such as lack of real-time feedback, reliance on subjective judgment, coarse stimulation parameters, and complex operation.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, embodiments of the present invention provide a closed-loop percutaneous spinal cord electrical stimulation analgesia system based on physiological feedback, comprising: An electrode patch, which has at least one pair of electrode units integrated on its flexible substrate, is used to attach to the corresponding spinal cord segment area on the body surface of the subject. The physiological signal acquisition module is used to acquire multimodal physiological signals from the subject in real time. The stimulator is electrically connected to the electrode patch and is used to generate and output an electrical stimulation signal to at least one pair of electrode units of the electrode patch. The control module, connected to the physiological signal acquisition module and the stimulator, assesses the subject's pain state based on the physiological signals acquired by the physiological signal acquisition module; and generates control commands to perform closed-loop regulation of the stimulator's output state based on the assessment results.

[0010] In one embodiment, the physiological signals acquired by the physiological signal acquisition module include at least one of electromyography (EMG), electroencephalography (EEG), and electrocardiogram (ECG) signals.

[0011] In one embodiment, the closed-loop regulation includes automatically controlling the on / off state of electrical stimulation or adjusting stimulation parameters; the stimulation parameters include: frequency, current intensity, pulse width, and stimulation duration.

[0012] In one embodiment, the electrode units are connected to the stimulator via independent wires or conductive paths, making each electrode unit electrically independent.

[0013] In one embodiment, the arrangement of the electrode units is designed according to the projection distribution of spinal cord segments on the body surface, covering multiple potential stimulation segments.

[0014] In one embodiment, the electrode unit of the electrode patch is made of a flexible material, and its conductive part is Ag / AgCl or conductive hydrogel material.

[0015] In one embodiment, the stimulator includes: The DDS module is used to generate electrical signals with corresponding preset waveforms for at least one pair of electrode units according to the instructions of the control module. An operational amplifier module, connected to the DDS module, is used to condition, amplify, and impedance match the generated electrical signal. A power amplifier module, connected to the operational amplifier module, is used to convert the amplified electrical signal into a constant current stimulation signal and output it to at least one pair of corresponding electrode units.

[0016] In one embodiment, the control module includes: a main controller and a display module, a keyboard module, and a storage module respectively connected to the main controller; The main controller is used to establish individualized baseline data or pain biomarker models based on the collected physiological signals before stimulation begins; the evaluation includes comparing real-time physiological signals with the baseline data or model; and is used to parse stimulation parameter instructions that can configure and simultaneously activate at least one pair of corresponding electrode units to achieve joint or distributed stimulation of multiple spinal cord segments. The display module is used to display the system's operating status, electrode unit configuration information, stimulation parameter information, and multimodal physiological signal information; The keyboard module is used to receive user operation commands, including: selecting electrode combinations, adjusting the intensity of stimulation, switching different stimulation modes, and starting or stopping stimulation therapy. The storage module is used to store stimulation parameter schemes, electrode combination schemes, physiological signal baseline data, and system operation data.

[0017] In one embodiment, the main controller is specifically used to assess pain status by determining whether the feature values ​​of real-time physiological signals exceed a threshold set based on the baseline data or model.

[0018] In one embodiment, the control module supports configuring electrode combinations using preset strategies or real-time commands, including single electrode unit activation, continuous activation of adjacent electrode units, or distributed activation of non-adjacent electrode units.

[0019] In a second aspect, embodiments of the present invention provide a closed-loop percutaneous spinal cord stimulation analgesia method based on physiological feedback, using the closed-loop percutaneous spinal cord stimulation analgesia system based on physiological feedback as described in any of the first aspects; the method includes the following steps: Step S1: Collect physiological signals from the subjects and establish individualized pain assessment benchmarks; Step S2: Apply transcutaneous electrical stimulation to the target spinal cord segment via electrode patches; Step S3: Collect physiological signals of the subject in real time during the stimulation process; Step S4: Compare and analyze the real-time collected physiological signals with the individualized pain assessment benchmark to determine the changes in the subject's pain status; Step S5: Automatically adjust the output state of the transcutaneous electrical stimulation based on the analysis results; Step S6: Repeat steps S2 to S5 until the stimulation ends.

[0020] In one embodiment, step S1, establishing an individualized pain assessment benchmark, includes: collecting physiological signals and corresponding subjective scores of subjects at different pain levels, and constructing a mapping relationship from physiological signal features to pain intensity through a machine learning model.

[0021] In one embodiment, step S5 includes: When physiological signals deviate from the baseline by more than a preset range, modulation is triggered, including adaptive adjustment of stimulation parameters to match the subject's real-time pain status.

[0022] As can be seen from the above technical solution, compared with the prior art, the present invention has the following technical advantages: (i) Introducing multimodal physiological feedback to achieve objectification of stimulus control This invention collects physiological signals such as electromyography, electroencephalography, and electrocardiography in real time and compares and analyzes them with pre-established baseline data. It directly introduces physiological feedback information into the stimulus control decision-making process, reducing reliance on subjective pain scores and improving the objectivity and repeatability of the stimulus regulation process.

[0023] (ii) Construct a closed-loop control mechanism to improve the adaptability of the stimulus process. Based on physiological feedback analysis, this invention automatically adjusts the on / off state and duration of percutaneous spinal cord stimulation, enabling the stimulation process to be dynamically adjusted according to changes in the subject's physiological state. This helps improve the adaptability of stimulation control to different individuals and at different time points.

[0024] (III) Achieving dynamic adjustment of individualized stimulation strategies under non-invasive conditions This invention uses surface electrodes for transcutaneous stimulation, combined with ultra-high frequency or time-domain interference electrical stimulation. While maintaining non-invasive characteristics, it achieves dynamic adjustment of individualized stimulation strategies through closed-loop control logic, taking into account both safety and flexibility.

[0025] (iv) Reduced operational complexity facilitates standardized clinical application By adjusting the stimulation state through an automated control module, this invention reduces the reliance on human experience and frequent manual operations during treatment, helps simplify the operation process, and improves the consistency of stimulation control among different operators and in different application scenarios.

[0026] (v) Modular design, with good system scalability and transformation potential. This invention adopts a modular system structure, which facilitates integration or upgrade with existing physiological signal acquisition equipment and transcutaneous electrical stimulation devices, providing a good technical foundation for subsequent medical device productization, registration and application, and clinical application. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0028] Figure 1 This is a structural diagram of the closed-loop percutaneous spinal cord electrical stimulation analgesia system based on physiological feedback provided in this embodiment of the invention; Figure 2 This is a flowchart of a closed-loop percutaneous spinal cord electrical stimulation analgesia method based on physiological feedback provided in an embodiment of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In related technologies, pain is a complex physiological process involving peripheral sensory input, central nervous system processing, and autonomic nervous system regulation. Its occurrence and intensity changes can cause measurable physiological responses in multiple systems. Electromyography (EMG), electroencephalography (EEG), and electrocardiography (ECG) signals reflect changes in pain-related neural activity at the levels of the motor system, central nervous system, and autonomic nervous system, respectively, and therefore can serve as objective physiological feedback indicators for assessing pain intensity.

[0031] Electromyography (EMG) signals primarily reflect the neuromuscular excitation state of skeletal muscles. Under painful stimuli or chronic pain, the body often exhibits protective muscle contractions, increased muscle tone, or abnormal movement patterns, manifested as increased amplitude, root mean square (RMS) value, or duration of EMG activity in the target muscle group. These changes are associated with pain-induced defensive motor responses and abnormal sensory-motor coupling.

[0032] Electroencephalography (EEG) signals reflect the cerebral cortex's processing of pain information. Pain can cause changes in the power distribution and frequency characteristics of EEG rhythms, such as changes in low-frequency or high-frequency EEG power in the resting or stimulated state, as well as changes in the synchronicity of neural activity in specific brain regions. These changes can characterize the intensity of pain-related central processing and the state of neural regulation.

[0033] Electrocardiogram (ECG) signals reflect the activity of the autonomic nervous system. Pain is usually accompanied by increased sympathetic nerve excitation and parasympathetic nerve inhibition, manifested as elevated heart rate, decreased heart rate variability, or changes in related time-domain and frequency-domain parameters. Therefore, ECG signals can be used to assess the level of autonomic nervous response induced by pain.

[0034] By integrating multimodal physiological signals such as electromyography, electroencephalography, and electrocardiography, pain status can be characterized from multiple dimensions, including motor response, central processing, and autonomic regulation, providing objective physiological feedback for pain intensity assessment and stimulation parameter adjustment in closed-loop analgesia stimulation systems.

[0035] Although existing percutaneous spinal cord stimulation (PSS) technology has shown some potential in pain intervention, the following shortcomings and limitations still exist in actual clinical application and medical device transformation: (i) The stimulation mode is mainly based on open-loop control and lacks a real-time feedback adjustment mechanism. Existing percutaneous spinal cord stimulation systems typically employ an open-loop control method with preset stimulation parameters. The stimulation frequency, intensity, and duration are mostly set by the operator before treatment. During stimulation, it is difficult to adjust in a timely manner according to the dynamic changes in the patient's pain state, making it difficult to adapt to individual differences and pain fluctuations, thus affecting the stability and consistency of analgesic effects.

[0036] (ii) High reliance on subjective patient feedback and insufficient objective assessment methods. Existing technologies rely heavily on patients' subjective pain scores or operators' experience in adjusting stimulation parameters. This results in a high degree of subjectivity, limited real-time performance and repeatability, which is not conducive to standardized control of the treatment process and increases the uncertainty of clinical operations.

[0037] (iii) Lack of effective linkage between physiological signals and stimulus control Although physiological signals such as electromyography (EMG), electroencephalography (EEG), and electrocardiography (ECG) have been used in pain-related research or efficacy evaluation, in existing percutaneous spinal cord stimulation devices, these physiological signals are mostly not involved in stimulation control decisions and have not yet formed an automatic regulation mechanism based on multimodal physiological feedback, making it difficult to achieve true closed-loop regulation.

[0038] (iv) The stimulation parameter adjustment method is crude, which easily leads to insufficient stimulation or overstimulation. In the absence of real-time physiological feedback, stimulation output can usually only be adjusted manually, which makes it difficult to reflect the patient's current tolerance and neurological response status in a timely manner. This may result in insufficient analgesia or cause discomfort, affecting patient compliance and the safety of clinical application.

[0039] (v) Clinical procedures rely on manual intervention, which is not conducive to promotion and standardized application. Existing technologies rely heavily on operator experience, requiring frequent manual observation and adjustments during treatment. This increases the workload of medical staff, hinders consistent treatment outcomes across different medical institutions, and poses challenges to the large-scale application and commercialization of medical devices.

[0040] This invention discloses a closed-loop percutaneous spinal cord electrical stimulation analgesia system based on physiological feedback. It is primarily used to dynamically assess and regulate pain levels by applying percutaneous electrical stimulation to corresponding spinal cord segments on the subject's body surface under non-invasive conditions, combined with real-time acquired physiological signals. It can be used in pain-related neuromodulation processes to automatically control the on / off state and duration of electrical stimulation, thereby assisting in achieving individualized and adjustable analgesic intervention.

[0041] Reference Figure 1 As shown, it includes: 1. An electrode patch, comprising one or more pairs of electrode units integrated on a flexible substrate, with each electrode unit arranged along a preset direction; used for attachment to the corresponding spinal cord segment area on the subject's body surface. The spatial position of each electrode unit on the patch is arranged according to the projection distribution of the spinal cord segment on the body surface. This integrated structural design allows multiple electrode units to cover multiple potential stimulation segment areas in a single attachment operation, providing a hardware basis for subsequent flexible selection of stimulation segments. The electrode patch is made of a flexible material suitable for surface attachment, adapting to the curved shape of the human back, improving attachment stability and user comfort, while ensuring reliable electrical contact of each electrode unit during stimulation.

[0042] This invention uses surface electrode patches as stimulation interfaces. The electrodes are attached to the spinal cord segments corresponding to the painful areas on the subject's body surface, applying electrical stimulation signals percutaneously to the target spinal cord segments. This design avoids invasive implantation procedures, reducing risks and operational complexity, and facilitating repeated use and widespread application in clinical and rehabilitation settings. The electrode patch positions can be customized according to the spinal cord segments corresponding to different pain distribution areas to achieve targeted neuromodulation, while also providing a foundation for stable transmission of subsequent stimulation signals.

[0043] 2. Physiological signal acquisition module, used to acquire multimodal physiological signals of the subject in real time; This invention includes a physiological signal acquisition module for acquiring real-time physiological feedback information from the subject during stimulation, including but not limited to electromyography (EMG), electroencephalography (EEG), and electrocardiography (ECG) signals. These physiological signals reflect neuromuscular activity, central nervous system activity characteristics, and changes in autonomic nervous function, providing objective data support for assessing the subject's current neural response. A data transmission channel is established between the physiological signal acquisition module and the control module to ensure that physiological signals are transmitted to the control module in real-time or near real-time during stimulation for subsequent analysis and decision-making.

[0044] 3. A stimulator, electrically connected to the electrode patch, outputs an electrical stimulation signal in the form of an ultra-high frequency carrier superimposed modulated wave to at least one pair of electrode units on the electrode patch. Stimulation parameters include frequency, current intensity, pulse width, and stimulation duration, which can be adjusted via a control module or set via a preset program. The stimulation parameters are decoupled from the physical layout of the electrodes. That is, different spinal cord segments can be percutaneously stimulated by selectively or in combination activating multiple electrode units.

[0045] The electrostimulator of this invention outputs an ultra-high frequency electrostimulation signal with a fixed carrier frequency and modulation frequency to an electrode patch, or a low-frequency modulated electrostimulation signal based on the principle of time-domain interference. Through this signal form, a modulated stimulation effect can be formed in the target neural structure region while stimulation is applied to the body surface, thereby meeting the requirements of percutaneous stimulation for penetration and controllability. The carrier frequency, modulation frequency, and output mode of the stimulation signal can be set or invoked as system parameters, providing a flexible technical basis for stimulation strategies under different individuals or application scenarios.

[0046] 4. Control module, connected to physiological signal acquisition module and stimulator, assesses the subject's pain state based on physiological signals acquired by physiological signal acquisition module; and generates control commands to perform closed-loop regulation of the stimulator's output state based on the assessment results.

[0047] Before or in the initial stage of system use, this invention collects physiological signals from the subject to establish corresponding baseline data, which characterizes the subject's basic physiological characteristics under specific conditions. During stimulation, the control module compares and analyzes the real-time collected physiological signals with the baseline data to identify trends or deviations in the physiological signals. This baseline-based analysis mechanism enables the system to assess an individual's neural response state without relying on subjective pain scores, providing a basis for subsequent stimulation control and thus achieving individualized adaptation of stimulation strategies.

[0048] The control module of this invention constructs a closed-loop control logic based on real-time physiological signal analysis results to automatically adjust the output state of the electrical stimulator. This output state includes, but is not limited to, stimulating on / off states and adjusting stimulation parameters; stimulation parameter adjustments include: frequency, current intensity, pulse width, and stimulation duration. By introducing a closed-loop control mechanism, the system can dynamically adjust the stimulation process according to the subject's current physiological feedback, avoiding the mismatch problems that may arise from a single fixed-parameter stimulation method at different individuals or time points, and improving the flexibility and consistency of the stimulation control process.

[0049] In addition, the control module can configure the activation mode of electrode units in multi-site electrode patches. The control module can select one or more pairs of electrode units for stimulation according to preset strategies or operator instructions, and determine the combination mode between the electrode units. By selectively activating or combining different electrode units, precise stimulation of a single spinal cord segment, or combined stimulation of multiple adjacent or non-adjacent spinal cord segments, can be achieved under the same electrode patch conditions, thereby improving the flexibility of the stimulation method.

[0050] The control module connects to the stimulator via a standard electrical interface, enabling unified control of the electrodes and management of stimulation signals. The control module can set stimulation parameters and output timing, and make necessary adjustments during operation. The control module supports real-time command configuration of electrode combinations, including single electrode unit activation, continuous activation of adjacent electrode units, or distributed activation of non-adjacent electrode units.

[0051] Specifically, each electrode unit is connected to the stimulator and control module via an independent wire or conductive path, making each electrode unit electrically independent. This independent lead-out design allows the control module to individually control the activation state of each electrode unit, providing conditions for selective or combined activation. This design avoids the problem of unchangeable electrode relationships in traditional fixed electrode pairs, providing a foundation for the subsequent flexible construction of different stimulation electrode combinations.

[0052] The closed-loop percutaneous spinal cord stimulation (PST) analgesia system provided by this invention can be used in analgesia treatment or pain management. It compares and analyzes physiological indicators such as electromyography (EMG), electroencephalography (EEG), and electrocardiography (ECG) with pre-established baseline data to determine the subject's current pain or neurological response state and adjust the output state of PST accordingly. This reduces reliance on subjective patient feedback and human experience, improving the objectivity and consistency of the stimulation control process. Applicable to PST-related medical device systems, it can be used as a control strategy for analgesia intervention in clinical treatment, rehabilitation training, and pain assessment assistance. It features standardized operation procedures, good repeatability, and easy integration with existing physiological signal acquisition modules and electrical stimulation devices, which is beneficial for the clinical application and standardized promotion of PST technology.

[0053] Furthermore, this system can selectively or in combination activate multiple electrode units located on the same electrode patch. Based on different stimulation needs, it flexibly determines the combination of electrode units involved in stimulation and their corresponding stimulation parameters, thereby adjusting the stimulation coverage and segment location to meet the percutaneous spinal cord stimulation requirements at different stages of use and in different application scenarios. This helps reduce the number of electrode patch replacements, simplifies the operation process, improves the flexibility and operability of the percutaneous spinal cord stimulation procedure, and facilitates its widespread application in various usage environments.

[0054] The following is combined Figure 1 The following is a further detailed description of the closed-loop percutaneous spinal cord electrical stimulation analgesia system based on physiological feedback provided by the present invention: I. Overall Architecture Overview; The system adopts a hierarchical modular design, referring to Figure 1 As shown, from left to right: The control module, acting as the "brain" of the system, is responsible for decision-making and interaction. It mainly assesses the subject's pain state based on the physiological signals collected by the physiological signal acquisition module. According to the assessment results, it generates control commands to perform closed-loop regulation of the stimulator's output state, including configuring the activation state, combination mode, and stimulation parameters of the electrode units.

[0055] The physiological signal acquisition module serves as the system's acquisition terminal, acquiring multimodal physiological signals from the subjects in real time.

[0056] The stimulator is the "heart" of the signal processing layer, responsible for power amplification and waveform generation; the electrical stimulation signal is transmitted to at least one pair of electrode units.

[0057] Electrode patches are the "terminals" of the execution layer as the system, and the corresponding combination of electrode units is responsible for energy output.

[0058] The signal flow follows this pattern: physiological signal monitoring → digital analysis and control → analog generation → power amplification → biological load.

[0059] II. Control Module; The control module includes: a main controller and a display module, a keyboard module, a communication module, and a storage module, which are respectively connected to the main controller; 1. The main controller uses an MCU module as the core controller of the control module. It is used to establish individualized baseline data or pain biomarker models based on the collected physiological signals before stimulation begins. The evaluation process includes comparing real-time physiological signals with baseline data or models. It is also used to parse stimulation parameter instructions, configure and simultaneously activate multiple pairs of electrode units, and send waveform data instructions to the stimulator to achieve joint or distributed stimulation of multiple spinal cord segments.

[0060] This part acts as the system's main controller, running embedded software and coordinating the operation of various peripherals. Its main tasks include: controlling the acquisition of baseline multimodal physiological signal data and mining individualized pain biomarkers; Before stimulation is applied or before stimulation begins, the physiological signal acquisition module is activated to collect multimodal physiological signal data of the subject at different pain levels. The data is then analyzed to identify biomarkers that can reflect the individual's pain level and to establish individualized baseline data.

[0061] Specifically, it includes: (1) Control the physiological signal acquisition module to acquire multimodal physiological signals such as electromyography, electroencephalography and / or electrocardiogram signals of the subject under different pain levels and corresponding pain intensity scores, including: acquiring the patient's physiological signals during the pain attack period and the pain non-attack period multiple times with the same preset duration; recording the patient's pain intensity score during each physiological signal acquisition process; taking each physiological signal and the corresponding pain intensity score as a physiological data with pain intensity label, and all physiological data with pain intensity label constitute a physiological dataset.

[0062] (2) Personalized pain biomarker mining: Based on the collected multimodal physiological signals and corresponding pain intensity scores under different pain states, pain biomarkers are determined from the multimodal physiological signals by preprocessing and feature extraction of the multimodal physiological data and by machine learning methods. The features extracted include, but are not limited to, the following: time domain or frequency domain features of EEG and EMG signals and heart rate or heart rate variability parameters in ECG signals.

[0063] Additionally, it includes: A) parsing stimulation parameters input by the user through the keyboard module or communication module, including frequency, pulse width, and amplitude; configuring the activation state, combination mode, and stimulation parameters of the electrode units to achieve selective or combined activation of the electrode units; B) sending waveform data to the stimulator's DDS module via the SPI / I²C bus; C) real-time monitoring of the stimulator's operating status, including overcurrent protection and open circuit detection; D) power consumption management and system safety status mechanisms.

[0064] 2. Display module, used to display the system's operating status, electrode unit configuration information, stimulation parameter information, and multimodal physiological signal information; The display module is an LCD, LED, or OLED screen, serving as the interactive display interface. Its main display content includes: A. Real-time stimulation intensity: mA-level current value; electrode unit configuration information; B. Working mode: continuous / intermittent / burst mode; C. Battery level and treatment countdown; D. Error codes, such as electrode detachment prompts; E. Multimodal physiological signal information, including electromyography, electroencephalography, and / or electrocardiogram signals.

[0065] 3. The keyboard module, as the input control terminal, is used to receive user operation commands, including: selection of electrode combinations, adjustment of stimulation intensity, switching between different stimulation modes, and stimulation parameter commands to start or stop stimulation therapy.

[0066] The keyboard module consists of physical buttons, capacitive touch or encoder knobs, and its main functions are as follows: A. Electrode combination selection, intensity increase / decrease keys, and output amplitude adjustment; B. Mode switching key, selecting different stimulation modes such as TENS / EMS; for example, when pain, soreness or local tension and discomfort occurs, the TENS mode is selected first; when muscle weakness occurs or muscle training is required, the EMS mode is selected first; C. Start / stop control key, emergency stop function.

[0067] 4. Communication Module The communication module is usually wired, such as USB / RS232, or it can be Bluetooth wireless, and can perform the following functions: A. Firmware upgrade and clinical data export; B. Wireless push of physiological signal baseline data and prescription parameters; C. Cloud synchronization of physiological signal baseline data and treatment data; D. Multi-device network management.

[0068] 5. Storage module, used to store stimulation parameter schemes, electrode combination schemes, physiological signal baseline data, and system operation data; This section mainly consists of EEPROM or Flash memory, primarily used to store the following: A) User-defined programs, such as multiple combinations of stimulation parameters and electrode combination schemes; B) Treatment logs, such as the duration of a single treatment and cumulative usage time; C) Calibration data, such as DAC zero-point offset and electrode impedance baseline values; D) Physiological signal baseline data, including: physiological signals of the subject at different pain levels and corresponding subjective scores, or a mapping relationship from physiological signal characteristics to pain intensity constructed through machine learning models.

[0069] III. Stimulator; The stimulator is the analog front end of the system, responsible for converting digital commands into constant current / constant voltage bioelectric stimulation signals and outputting electrical stimulation signals to at least one pair of electrode units of the multi-site electrode patch. It mainly consists of the following parts: 1. The DDS module generates electrical signals with corresponding preset waveforms for at least one pair of electrode units according to the instructions of the control module; that is: Direct Digital Frequency Synthesis - Waveform Generation Stage; Technical principle: High-precision sine / square / triangle waves are generated using a lookup table (LUT) method. Frequency range: 1kHz~50kHz, which can cover the effective stimulation frequency band of neuromuscular nerves; Resolution: 32-bit frequency control word, stepping accuracy up to 0.01Hz; Waveform type: Supports arbitrary waveforms (AWG), and can simulate exponentially decaying pulses; Interface with MCU: SPI serial communication, real-time update of frequency / phase register.

[0070] 2. The operational amplifier module Op-Amp, as a voltage amplification stage, is connected to the DDS module to condition, amplify, and impedance match the generated electrical signal; Circuit topology: typically a non-inverting amplifier or instrumentation amplifier structure; Main functions: A. Signal conditioning: Filters out high-frequency image noise from the DDS output, i.e., low-pass filtering; B. Voltage amplification: Amplifies the 0~3.3V signal from the DDS output to the ±12V~±100V range; C. Impedance matching: Provides high input impedance, low output impedance, and isolates the front and rear stages.

[0071] 3. The Power Amp module, acting as a current amplification stage, is connected to the operational amplifier module to convert the amplified electrical signal into a constant current stimulation signal and output it to the corresponding electrode patch.

[0072] Topology: Typically uses Class AB or H-bridge (full bridge) output stages; Main functions: A. Current boost: Converts voltage signals into constant current output, and the constant current source characteristics are safer for biological loads; B. Electrical isolation: Isolates the patient end from the circuit end through a transformer or optocoupler, in compliance with medical safety standard IEC60601; C. Protection functions: Integrates overcurrent limiting, short circuit protection, and thermal shutdown; D. Output capability: Typical value adjustable from 0 to 100mA, open circuit voltage up to 80 to 120V, which can overcome skin impedance.

[0073] In one embodiment, the stimulator outputs an electrical stimulation signal with an ultra-high frequency carrier wave, the carrier frequency being in the range of 1 kHz to 50 kHz, preferably 5 kHz to 20 kHz, and may be superimposed with low-frequency modulation components. The stimulation duration is more than 20 minutes. The waveform and modulation method of the electrical stimulation signal include, but are not limited to, continuous wave, pulse wave, amplitude modulation, frequency modulation, or time-domain interference modulation, to act on the neural activity of the target spinal cord segment.

[0074] IV. Electrode patch, which has at least one pair of electrode units integrated on a flexible substrate, with each electrode unit arranged along a preset direction; used to attach to the corresponding spinal cord segment area on the subject's body surface. The electrode units are made of flexible material, and their conductive parts are Ag / AgCl or conductive hydrogel material.

[0075] like Figure 1 As shown in the figure, the arrangement and combination of the electrode patch stimulation units on the right are schematic. The arrangement is not limited to that shown in the figure.

[0076] The spinal cord consists of different segments from top to bottom, and different spinal cord segments control the sensory and motor functions of different limbs and trunk areas.

[0077] Figure 1The image shows a multi-site electrode patch in the right-hand region, with the orange area representing the spinal cord region, covering a portion of the spinal cord segments. A1-A6, B1-B6, C1-C6, D1-D6, and E1-E6 are different electrode units. By combining different electrode units, sensory and motor neurons within different spinal cord segments can be stimulated, thereby altering the sensorimotor functions of the corresponding limbs or trunk controlled by that spinal cord segment.

[0078] Electrode unit combinations include, but are not limited to, the following combinations: 1. By selecting two electrode units from C1 to C6, stimulation of one spinal cord segment (e.g., C1 and C2) or multiple spinal cord segments (e.g., C1 and C6) can be achieved; 2. By selecting two electrode units on both sides of the spinal cord, stimulation of any segment of the spinal cord can be achieved by the electrode patch covering the area, such as B3 and D3, A1 and D3, A1 and E4, etc. 3. By selecting any number of electrode pairs from C1 to C6, selective stimulation of multiple spinal cord segments can be achieved, such as: C1 and C2 + C4 and C6; 4. By selecting any number of electrode pairs on both sides of the spinal cord, selective stimulation of one or more spinal cord segments can be achieved, such as B3 and D3 + A5 and E5, etc.

[0079] Electrical characteristics Load impedance: The equivalent impedance of human skin + tissue is approximately 1kΩ~10kΩ, which can be adjusted according to humidity. Current density: Must meet safety standards, less than 2mA / cm², to avoid tissue burns.

[0080] V. Physiological signal acquisition module, including: 1. Electromyography (EMG) signal acquisition submodule, used to acquire EMG signals reflecting the neuromuscular excitation state of skeletal muscle in order to assess changes such as defensive muscle contraction and increased muscle tone caused by pain.

[0081] For example, a surface electromyography (EMG) sensor is typically used, which includes a pair of differential electrodes and a reference electrode. These are directly attached to the skin surface of the target muscle group, such as the trapezius or back muscles, in pain-related areas, to collect microvolt-level electrical signals generated by muscle activity. The signals are then amplified and filtered by an EMG amplifier to remove interference.

[0082] 2. EEG signal acquisition submodule, used to acquire EEG signals that reflect the cerebral cortex’s processing of pain information and analyze characteristics such as changes in EEG rhythm power caused by pain.

[0083] For example, an EEG acquisition cap or scalp electrodes can be used. Depending on the accuracy requirements of the application scenario, it can be a multi-lead electrode cap arranged according to the international 10-20 system, or a simplified version with a small number of dry or wet electrodes applied to key locations such as the forehead. The acquired microvolt-level signals need to be processed by an EEG amplifier with high input impedance and high common-mode rejection ratio.

[0084] 3. ECG signal acquisition submodule, used to acquire ECG signals reflecting changes in autonomic (sympathetic / parasympathetic) activity induced by pain, and monitor parameters such as heart rate and heart rate variability.

[0085] For example, standard ECG electrodes, such as disposable Ag / AgCl electrodes, are used and attached to the skin of the chest with specific leads to collect ECG signals. Alternatively, a photoplethysmography (PPG) sensor can be integrated into a wristband or finger cot to indirectly acquire heart rate information. The signal is then processed by an ECG amplifier.

[0086] The closed-loop percutaneous spinal cord electrical stimulation analgesia system based on physiological feedback provided by this invention operates on the following principle in specific implementation: (1) The stimulation electrode patch is attached to the subject's body surface location corresponding to the target spinal cord segment involved in spinal cord sensory processing and / or sensory-motor modulation, and at least one physiological signal acquisition electrode is placed to acquire electromyographic signals, electroencephalogram signals and / or electrocardiogram signals. The subject is in a resting or relaxed state, and the system completes signal channel detection and initialization settings.

[0087] For example, in one embodiment, the subject is in a resting state, and electromyography (EMG) signals of the target muscle group are collected for 30–60 seconds to reflect pain-related muscle tension or defensive activity; resting electroencephalography (EEG) signals are collected for at least 3 minutes to extract rhythmic features related to pain center processing; and electrocardiogram (ECG) signals are continuously collected for at least 5 minutes to calculate pain-related autonomic regulatory indices. These physiological signals serve as characteristic input parameters for pain state assessment, used to determine pain intensity and electrical stimulation status.

[0088] (2) Baseline multimodal physiological signal data acquisition and individualized pain biomarker mining: Before stimulation is applied or stimulation begins, the physiological signal acquisition module is activated to collect multimodal physiological signal data of subjects under different pain levels, analyze and determine biomarkers that can reflect individual pain levels, and establish individualized baseline data.

[0089] (3) The control module controls the electrical stimulator to output a transcutaneous spinal cord electrical stimulation signal to the electrical stimulation electrode.

[0090] (4) During the stimulation process, the physiological signal acquisition module continuously acquires the physiological signals of the subject and transmits the acquired signals to the control module in real time or near real time to reflect the neurological and physiological response status of the subject during the stimulation process; the control module preprocesses the acquired physiological signals and extracts biomarker characteristic parameters to characterize the subject's pain status.

[0091] (5) The control module processes the physiological signals collected in real time, extracts the pain biomarker characteristic parameters in real time, assesses the pain status of the subject in real time, and compares them with the preset pain threshold to determine the current pain level of the subject and whether electrical stimulation intervention is needed.

[0092] Specifically, it includes: 1) Pain threshold setting step: Set the maximum value of the pain biomarker response value corresponding to the pain-free period of the subject as the pain threshold, and send the pain threshold to the pain assessment step; 2) Pain assessment steps: Based on real-time acquired multimodal physiological signals, calculate the corresponding pain biomarker response values; compare the pain biomarker response values ​​with the pain threshold; when the pain biomarker response value is greater than the pain threshold, determine that the subject is in a pain state and generate an electrical stimulation control trigger signal.

[0093] (6) Closed-loop control and adjustment: Based on the physiological feedback analysis results, the control module generates control commands to automatically adjust the output state of the electrical stimulator. The adjustment includes, but is not limited to, turning the electrical stimulation on and off, adjusting the stimulation duration, adjusting the stimulation intensity, or switching the combination of stimulation parameters, thereby forming a closed-loop control process based on physiological feedback.

[0094] (7) Stimulation effect assessment: After the stimulation intervention, the system records the changes in physiological signals before, during and / or after stimulation to assess the changes in the subjects' physiological response and the stimulation effect during the closed-loop regulation process.

[0095] The closed-loop percutaneous spinal cord electrical stimulation analgesia system based on physiological feedback provided by this invention adopts a modular design in its system structure. The electrode patches, electrical stimulator, physiological signal acquisition module, and control module are functionally divided, and the modules are connected and work collaboratively through standardized interfaces. This design facilitates system maintenance, upgrades, and integration with existing medical devices. Simultaneously, this modular structure allows for the expansion or adjustment of physiological signal types, stimulation strategies, or control logic according to different clinical or rehabilitation application needs, providing technical support for subsequent medical device registration and productization.

[0096] Based on the same inventive concept, embodiments of the present invention also provide a closed-loop percutaneous spinal cord stimulation analgesia method based on physiological feedback, using the closed-loop percutaneous spinal cord stimulation analgesia system based on physiological feedback as described in the above embodiments, referring to... Figure 2 As shown, the method includes the following steps: Step S1: Collect physiological signals from the subjects and establish an individualized pain assessment benchmark. The establishment of the individualized pain assessment benchmark includes: collecting physiological signals and corresponding subjective scores from the subjects at different pain levels, and constructing a mapping relationship from physiological signal characteristics to pain intensity through a machine learning model.

[0097] Step S2: Apply transcutaneous electrical stimulation to the target spinal cord segment via electrode patches; Step S3: Collect physiological signals of the subject in real time during the stimulation process; Step S4: Compare and analyze the real-time collected physiological signals with the individualized pain assessment benchmark to determine the changes in the subject's pain status; Step S5: Automatically adjust the output state of the transcutaneous electrical stimulation based on the analysis results; if the physiological signal deviates from the baseline by more than a preset range, the adjustment is triggered, including adaptive adjustment of stimulation parameters to match the subject's real-time pain state.

[0098] Step S6: Repeat steps S2 to S5 until the stimulation ends.

[0099] The above-described method eliminates the need for frequent manual intervention in setting and adjusting stimulation parameters; the system can adaptively adjust to different individuals' pain responses, avoiding a "one-size-fits-all" approach; it is objective, reliable, safe, efficient, and easy to operate, making it suitable for home or clinical use.

[0100] The following is a further explanation of each of the above steps: Step S1: Multimodal physiological signal acquisition and construction of personalized pain biomarkers Before percutaneous spinal cord stimulation begins, multimodal physiological signals of subjects under different pain states are collected and combined with subjective pain intensity scores to analyze and construct physiological feedback biomarkers that can characterize the degree of individual pain, and establish an individualized pain baseline model.

[0101] Step S1 specifically includes: (1) Multimodal physiological signal acquisition steps: Through the multimodal physiological signal acquisition module, the electromyography, electroencephalography and / or electrocardiogram signals of the subject are collected multiple times during the pain attack period and the pain non-attack period with the same preset acquisition time; during each physiological signal acquisition process, the corresponding subjective pain intensity score is recorded synchronously; each physiological signal and its corresponding pain intensity score are used as a physiological data with pain intensity label, and all physiological data with pain intensity label together constitute the physiological dataset.

[0102] (2) Personalized pain biomarker mining steps: Based on the physiological dataset, the multimodal physiological signals are preprocessed and feature extracted sequentially, wherein the preprocessing includes filtering, bad segment removal and independent principal component analysis; the extracted physiological features and the corresponding pain intensity labels are combined to form a physiological feature dataset, and the physiological feature dataset is input into a regression model or other machine learning prediction model to establish a mapping relationship between pain intensity and physiological feature parameters, thereby obtaining pain biomarkers for characterizing individual pain status; wherein the physiological feature parameters include, but are not limited to: time domain or frequency domain features of EEG and EMG signals, and heart rate and / or heart rate variability parameters in ECG signals.

[0103] Step S2: Application of percutaneous spinal cord electrical stimulation By applying percutaneous spinal cord electrical stimulation signals to target spinal cord segments through stimulation electrodes placed on the body surface, the pain state of the subject can be modulated.

[0104] Step S3: Real-time acquisition of physiological signals During the application of percutaneous spinal cord electrical stimulation, the subject's electromyography (EMG), electroencephalography (EEG), and / or electrocardiogram (ECG) signals are collected in real time or periodically, and the physiological signals are input into the control module. The control module preprocesses the collected physiological signals and extracts biomarker characteristic parameters to characterize the subject's pain state.

[0105] Step S4: Real-time pain assessment and physiological feedback determination Based on the pain biomarker feature parameters extracted in real time in step S3, the subject's pain status is assessed in real time and compared with a preset pain threshold to determine whether electrical stimulation intervention is needed. Specifically, this includes: (1) Pain threshold setting steps: Set the maximum value of the pain biomarker response value of the subject during the pain-free period as the pain threshold, and send the pain threshold to the pain assessment module; (2) Pain assessment steps: The pain assessment module calculates the corresponding pain biomarker response value based on the real-time acquired multimodal physiological signals; compares the pain biomarker response value with the pain threshold; when the pain biomarker response value is greater than the pain threshold, it determines that the subject is in a pain state and generates an electrical stimulation control trigger signal.

[0106] Step S5: Adaptive adjustment of stimulus state Based on the evaluation results of step S4, the control module automatically generates control commands to adjust the output state of percutaneous spinal cord stimulation. The adjustment includes turning the stimulation on and off, adjusting the stimulation duration, and / or switching the stimulation parameters, thereby realizing closed-loop percutaneous spinal cord stimulation analgesia control based on physiological feedback.

[0107] Step S6: Repeat steps S2 to S5 until the stimulation intervention ends.

[0108] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0109] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A closed-loop percutaneous spinal cord electrical stimulation analgesia system based on physiological feedback, characterized in that, include: An electrode patch, which has at least one pair of electrode units integrated on its flexible substrate, is used to attach to the corresponding spinal cord segment area on the body surface of the subject. The physiological signal acquisition module is used to acquire multimodal physiological signals from the subject in real time. The stimulator is electrically connected to the electrode patch and is used to generate and output an electrical stimulation signal to at least one pair of electrode units of the electrode patch. The control module, connected to the physiological signal acquisition module and the stimulator, assesses the subject's pain state based on the physiological signals acquired by the physiological signal acquisition module; and generates control commands to perform closed-loop regulation of the stimulator's output state based on the assessment results.

2. The system according to claim 1, characterized in that, The physiological signals acquired by the physiological signal acquisition module include at least one of electromyography (EMG), electroencephalography (EEG), and electrocardiogram (ECG) signals.

3. The system according to claim 1, characterized in that, The closed-loop regulation includes automatically controlling the on / off state of electrical stimulation or adjusting stimulation parameters; the stimulation parameters include: frequency, current intensity, pulse width, and stimulation duration.

4. The system according to claim 1, characterized in that, The electrode unit of the electrode patch is made of flexible material, and its conductive part is Ag / AgCl or conductive hydrogel material.

5. The system according to claim 1, characterized in that, The stimulator includes: The DDS module is used to generate electrical signals with corresponding preset waveforms for at least one pair of electrode units according to the instructions of the control module. An operational amplifier module, connected to the DDS module, is used to condition, amplify, and impedance match the generated electrical signal. A power amplifier module, connected to the operational amplifier module, is used to convert the amplified electrical signal into a constant current stimulation signal and output it to at least one pair of corresponding electrode units.

6. The system according to claim 1, characterized in that, The control module includes: a main controller and a display module, a keyboard module, and a storage module respectively connected to the main controller; The main controller is used to establish individualized baseline data or pain biomarker models based on the collected physiological signals before stimulation begins; the evaluation includes comparing real-time physiological signals with the baseline data or model; and is used to parse stimulation parameter instructions that can configure and simultaneously activate at least one pair of corresponding electrode units to achieve joint or distributed stimulation of multiple spinal cord segments. The display module is used to display the system's operating status, electrode unit configuration information, stimulation parameter information, and multimodal physiological signal information; The keyboard module is used to receive user operation commands, including: selecting electrode combinations, adjusting the intensity of stimulation, switching different stimulation modes, and starting or stopping stimulation therapy. The storage module is used to store stimulation parameter schemes, electrode combination schemes, physiological signal baseline data, and system operation data.

7. The system according to claim 6, characterized in that, The main controller is specifically used to assess pain status by determining whether the feature values ​​of real-time physiological signals exceed a threshold set based on the baseline data or model.

8. A closed-loop percutaneous spinal cord electrical stimulation analgesia method based on physiological feedback, characterized in that, Using the closed-loop percutaneous spinal cord electrical stimulation analgesia system based on physiological feedback as described in any one of claims 1-7; the method includes the following steps: Step S1: Collect physiological signals from the subjects and establish individualized pain assessment benchmarks; Step S2: Apply transcutaneous electrical stimulation to the target spinal cord segment via electrode patches; Step S3: Collect physiological signals of the subject in real time during the stimulation process; Step S4: Compare and analyze the real-time collected physiological signals with the individualized pain assessment benchmark to determine the changes in the subject's pain status; Step S5: Automatically adjust the output state of the transcutaneous electrical stimulation based on the analysis results; Step S6: Repeat steps S2 to S5 until the stimulation ends.

9. The method according to claim 8, characterized in that, In step S1, establishing an individualized pain assessment benchmark includes: collecting physiological signals and corresponding subjective scores of subjects under different pain levels, and constructing a mapping relationship from physiological signal characteristics to pain intensity through a machine learning model.

10. The method according to claim 8, characterized in that, Step S5 includes: When physiological signals deviate from the baseline by more than a preset range, modulation is triggered, including adaptive adjustment of stimulation parameters to match the subject's real-time pain status.

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