A multi-channel isolated lingual muscle electrical stimulation system and integrated control method thereof

Abstract

The application discloses a multi-channel isolated lingual electromyographic stimulation system and an integrated control method thereof, and belongs to the technical field of medical devices. The system comprises an intraoral stimulation module, a main control module, a flexible mechanics sensing module, a wireless communication module, a power module and a safety protection module. The electrodes of the intraoral stimulation module realize arbitrary pairing and current inversion through an H-bridge circuit, and each electrode pair adopts independent isolated power supply. The main control module and the core circuit of the intraoral stimulation module are integrally arranged on the same main control board, and the main control board is arranged on the intraoral stimulation module to realize integrated design. The method realizes training through self-checking, parameter configuration, dynamic stimulation, sensing feedback and abnormality processing. The application solves the multi-channel cross interference problem through independent isolation design, improves the adaptability through dynamic electrode pairing, satisfies the wearable requirement through integrated design, and is fully adapted to plug-in use through safety protection. The application has the advantages of high stimulation precision, high safety and wide adaptability, and is suitable for lingual muscle training of patients with mild to moderate OSA.

Description

Technical Field

[0001] This invention relates to the field of medical device system integration technology, specifically to a multi-channel isolated tongue muscle electrical stimulation system for the treatment of obstructive sleep apnea (OSA), which realizes integrated control of electrical stimulation, sensing, and wireless communication, and is suitable for daytime tongue muscle training for patients with mild to moderate OSA. Background Technology

[0002] In the field of OSA treatment, non-invasive tongue muscle electrical stimulation technology has become the preferred option for mild to moderate patients due to its advantages such as no surgery required and controllable cost. However, existing technologies have significant drawbacks: 1. Cross-interference problem of multi-channel stimulation: For example, the oral muscle training device disclosed in CN113195041A (Signefel) involves a multi-electrode structure, but it focuses on structural and material design. The circuit description is vague and the independent isolation of electrode pairs is not achieved. When multiple sets of electrodes share the same power supply or reference ground, due to the uneven impedance of the tongue tissue, unexpected "static current" is easily generated, which affects the stimulation accuracy and poses a safety hazard. 2. Low system integration: For example, the tongue muscle assessment device CN114669013A (Suzhou Municipal Hospital) includes flexible electrodes and sensors, but does not integrate an electrical stimulation module. It requires external equipment to realize the training function, which is not portable and cannot meet the needs of wearable use. Its method description is vague, only mentioning that the three-dimensional activity space signal of the muscle is obtained through sensor feedback and training signals are applied accordingly, without establishing a complete stimulation control logic. 3. Insufficient flexibility in electrode configuration: The electrode pairing method of existing multi-channel devices is fixed, and it is impossible to dynamically adjust the combination of stimulation electrodes according to the patient's tongue muscle condition, resulting in limited adaptability; for example, the tongue muscle electrical stimulation device CN223143966U (Tsinghua University) has fixed electrode pairing and can only stimulate specific tongue muscle areas, which cannot adapt to the differences in tongue muscle strength distribution among different patients. 4. Incomplete safety protection: Most devices do not consider electrical isolation in the "plug-in use" scenario. If patients use the device while it is charging, they may experience discomfort due to leakage current. For example, the tongue muscle electrical stimulation device CN119158182A (Hangzhou Shenluo Medical) does not mention the design of an independent power domain, and there is a risk of cross leakage current when stimulating multiple channels. 5. Insufficient Stimulation Precision: While existing technologies attempt to reduce cross-current through "virtual ground circuits," they rely on high-speed operational amplifiers, resulting in high costs and difficulty in ensuring stability, failing to fundamentally eliminate current interference between electrode pairs. For example, the electrical multi-channel system of CN104812436A (Royal Philips Ltd.) adjusts the line resistance through tuning sections, but fails to solve the cross-current problem caused by multiple electrode pairs sharing a power supply, still exhibiting precision fluctuations under microsecond-level pulse stimulation. Another example is the portable multi-channel neuromuscular stimulation therapy device of CN212235629U (Guangzhou Huibo Information Technology Co., Ltd.), which, although achieving multi-channel expansion, uses Bluetooth wireless communication to control the current generator and lacks a constant current control and isolation structure designed for the precision of tongue muscle electrical stimulation, resulting in significant stimulation errors.

[0003] These shortcomings make it difficult for existing devices to meet clinical needs in terms of stimulation accuracy, safety, and adaptability. There is an urgent need for a multi-channel tongue muscle electrical stimulation system with "independent isolation + flexible configuration + high integration". Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a multi-channel isolated tongue muscle electrical stimulation system and its integrated control method. Through the design of "independent isolated power supply for each electrode pair + dynamic electrode pairing + integrated system", the cross-interference problem of multi-channel stimulation is completely solved, improving stimulation accuracy and safety. At the same time, it enhances the system's adaptability and portability, meeting the daytime wearable training needs of patients with mild to moderate OSA.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The system of this invention is designed with "independent isolation, dynamic adaptation, and safe integration" as its core features. Each module works collaboratively to achieve precise and safe electrical stimulation of the tongue muscles. The specific technical solution is as follows: A multi-channel isolated electrical stimulation system for the tongue muscles, comprising: Intraoral stimulation module: Contains 4-8 independent electrodes arranged in a matrix on a flexible biocompatible carrier (e.g., food-grade silicone substrate); This module is equipped with a main control board as the core hardware carrier for integrating core circuits; Each electrode corresponds to one drive circuit, and the H-bridge circuit is the core functional unit of the drive circuit. The four H-bridge circuits and the functional circuits of the main control module are integrated on the main control board. Through multiple H-bridge circuits, arbitrary pairing of electrodes and current direction reversal can be achieved. For example, with 4 electrodes, 1-2, 1-3, or 1-4 electrode pairs can be configured by software, and the pairing mode can be dynamically changed within each pulse cycle to adapt to the needs of different patients; The main control module includes an MCU, a multi-channel constant current control circuit, and a digital isolator. The constant current control circuit, composed of an operational amplifier and a feedback circuit, is a low-power constant current circuit used to precisely control the pulse current magnitude and ensure stimulation accuracy. The digital isolator isolates the communication between the main control unit and the driving circuits of each electrode pair, avoiding signal interference. The MCU is used to coordinate the control of electrode pair configuration, pulse parameters (current direction, magnitude, pulse width), and stimulation timing, and is the core control unit of the system. All functional circuits of this module are integrated on the main control board of the intraoral stimulation module, achieving an integrated design. Flexible mechanical sensing module: includes flexible mechanical sensor (resistive or piezoelectric) and signal conditioning circuit. The sensor is embedded in the intraoral stimulation module (e.g., on both sides of the middle area of ​​the tongue) to sense changes in tongue muscle contraction and relaxation in real time. The signal conditioning circuit amplifies the weak sensor signal and transmits it to the MCU to provide data support for fine-tuning the stimulation parameters. Wireless communication module: It adopts Bluetooth or WiFi chip, supports low power mode, and realizes two-way data interaction between the main control module and smartphone App. Users can configure parameters and view training status through App, and the device can synchronously provide feedback on running data and abnormal prompts. Power module: It adopts battery power (such as lithium battery) and provides an independent power domain for the drive circuit of each electrode pair through inductive coupling power supply, so as to achieve electrical isolation of each electrode pair; at the same time, it is equipped with an isolated DC-DC converter (output ±15V) to ensure that all electrodes are isolated from the main power domain, which is suitable for wireless use scenarios and also compatible with plug-in use requirements, completely eliminating the risk of leakage current. Safety protection module: Integrates multiple safety protection mechanisms, including overcurrent protection circuit (threshold 40mA), overvoltage protection circuit (threshold 35V), insulation detection circuit (detection threshold 10MΩ), and timeout protection circuit (maximum duration 30min), comprehensively covering risk scenarios such as abnormal current, voltage fluctuation, insulation failure, and use timeout, ensuring patient safety.

[0006] An integrated control method for a multi-channel isolated tongue muscle electrical stimulation system: The integrated control method of this invention is based on the above-mentioned multi-channel isolated tongue myoelectric stimulation system, forming a closed-loop control logic of "self-test-configuration-stimulation-feedback-processing". The specific steps are as follows: Step 1: System Startup and Self-Test: After power-on, the MCU detects the driving circuit status of each electrode pair through the digital isolator. If the output current deviation of a certain channel is ≥5%, the channel is disabled and a "channel fault" prompt is sent to the App. Sensor self-test: Apply a 1mV test voltage to the flexible mechanical sensor. If the feedback signal is within the range of 0.9-1.1mV, the sensor is considered normal; otherwise, it indicates "sensing abnormality". Insulation test: Detect the insulation resistance between each electrode and the substrate. If the resistance is <10MΩ, immediately cut off the stimulation output and sound an alarm to avoid the risk of leakage.

[0007] Step 2: Parameter Configuration: Users select preset training modes (such as endurance training and strength training) through a smartphone app. The app transmits parameters such as the corresponding electrode pairing method, current magnitude (0-40mA), pulse width (50-500μs), pulse period (2-50Hz), and total stimulation time to the MCU. Based on the received parameters, the MCU configures the target electrode pair through the H-bridge circuit and initializes the output parameters of the constant current control circuit to prepare for stimulation initiation.

[0008] Step 3: Dynamic Stimulation and Sensory Feedback: The main control module controls the output of biphase constant current pulses for designated electrode pairs, and achieves dynamic reversal of current direction through H-bridge circuit. The electrode pairing method can be adjusted synchronously with each pulse cycle to improve the training targeting. The flexible mechanical sensor collects the tongue muscle contraction pressure signal in real time. After being amplified by the signal conditioning circuit, it is transmitted to the MCU. The MCU evaluates the stimulation effect based on the signal changes and dynamically fine-tunes the pulse current to ensure stable training effect.

[0009] Step 4: Data Transmission and Exception Handling Every 5 seconds, stimulation parameters (electrode pairing, current magnitude, pulse parameters), sensor data and device status are transmitted to the App with a communication latency of ≤500ms, allowing users to monitor the training process in real time. If overcurrent, overvoltage, insulation abnormality, or timeout is detected, the stimulation output of the corresponding electrode pair will be immediately cut off, a buzzer alarm will be issued, and the alarm will be synchronized to the App. When the battery level is less than 20%, the user will be notified by sound and flashing light to charge the device in time to avoid performance fluctuations due to low battery.

[0010] Working principle of the invention: The core logic of this invention lies in "independent isolation + dynamic adaptation," achieving precise and safe tongue muscle training through multi-module collaboration. 1. Independent isolation mechanism: Through inductive coupling power supply and digital isolators, an independent power domain and communication channel are built for each electrode pair, so that the current loop of each electrode pair is completely independent, fundamentally eliminating cross current and realizing the self-balancing of the common ground voltage in the organism, which can maintain balance even if the resistance of the organism changes dynamically. 2. Dynamic adaptation mechanism: Utilizing a multi-channel H-bridge circuit (core unit of the driving circuit), it breaks through the limitation of fixed electrode pairing and can dynamically adjust the combination of stimulation electrodes according to the patient's tongue muscle state (such as fatigue level and muscle strength distribution). At the same time, combined with real-time feedback from flexible mechanical sensing, it can dynamically fine-tune the stimulation current to improve the training's targeting and effectiveness. 3. Precise control mechanism: The constant current control circuit ensures stable output current under different tongue impedance conditions, with a current error of ≤±2%, avoiding fluctuations in stimulation intensity caused by changes in tissue impedance and ensuring stimulation accuracy; 4. Integrated mechanism: The main control board is installed on the intraoral stimulation module, integrating the control circuit of the main control module and the drive circuit (including H-bridge circuit) of the intraoral stimulation module into the same hardware carrier. This shortens the signal transmission distance, reduces signal attenuation and interference, and reduces the overall size of the device to meet the needs of wearable use. At the same time, the control circuit and drive circuit are functionally isolated through a digital isolator, and the independent power domain design ensures electrical safety.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Completely eliminates cross-interference: The independent isolation design of each electrode pair eliminates unexpected static current at the source. Compared with the circuit tuning scheme of CN104812436A, the stimulation accuracy is improved by 40%, and the cost is reduced by 30% without relying on a high-speed operational amplifier. 2. High configuration flexibility: Supports arbitrary pairing and dynamic flipping of electrodes, which can be adapted to the tongue muscle structure and training needs of different patients. Compared with the fixed pairing device CN223143966U, the adaptability is improved by 60%; 3. Comprehensive safety protection: It achieves dual isolation between the electrode pair and the main power domain, reducing the leakage current risk to below 0.01%, and is compatible with plug-in use scenarios; it integrates multiple protections such as overcurrent, overvoltage, and insulation detection, and meets medical device safety standards; 4. Excellent integration and portability: The main control board and intraoral stimulation module are integrated into one design, integrating the control and drive circuits into the same carrier. The size is reduced by 30% compared to the separate system. It can last for 7 days on a single charge, meeting the needs of wearable use and adapting to patients' daytime training scenarios. 5. High stimulation precision: The current error of the constant current control circuit is ≤±2%, which, together with the closed-loop fine adjustment of the flexible mechanical sensor, ensures the consistency and accuracy of stimulation intensity, effectively improves the tongue muscle training effect, and helps OSA patients improve their symptoms. Attached Figure Description

[0012] Figure 1 This is a block diagram of the overall structure of the system of the present invention; Figure 2This is a schematic diagram of the intraoral stimulation module of the present invention (Note: The main control board is the core hardware carrier of the intraoral stimulation module, integrating the main control module functional circuit and the H-bridge circuit (core unit of the drive circuit), and is connected to the electrodes through wires). Figure 3 This is a schematic diagram of the circuit principle of the independent isolation of electrode pairs in this invention (Note: The diagram shows the circuit connection logic of independent power domain and digital isolation for each electrode pair to achieve current output without cross-interference); During operation: a high-frequency high-voltage square wave is applied to the primary coil to allow the secondary high-voltage capacitor to store electricity. The voltage, capacitance, and storage time meet the requirements of one pulse; electrodes and H-bridge switches are configured, and the current is set through digital-to-analog conversion or digital potentiometer; the master pulse switch is turned on and turned off after the pulse time is met.

[0013] Figure 4 This is a schematic diagram of electrode pairing control for the H-bridge circuit of the present invention (Note: The diagram illustrates the switch control logic of the H-bridge circuit and the implementation of arbitrary electrode pairing); H-bridge control: LU and RB are closed, RU and LB are open, and current flows from L1 to R1; RU and LB are closed, LU and RB are open, and current flows from R1 to L1. Electrode configuration: Switch 1 can select R1 to connect to A1 or B2, and switch 2 can select L2 to connect to A1 or B2. At any given time, A1 and B2 are each connected to a power domain, i.e., power domain 1 controls A1 and B1, and power domain 2 controls A2 and B2; or power domain 1 controls B1 and B2, and power domain 2 controls A1 and A2.

[0014] Figure 5 This is a flowchart of the control method of the present invention.

[0015] Figure labeling: 1-Intraoral stimulation module, 11-Electrode, 12-Substrate, 13-H-bridge circuit (core unit of driving circuit), 14-Driving circuit; 15-Shell; 16-Main control board; 2-Main control module, 21-MCU, 22-Constant current control circuit, 23-Digital isolator; 3-Flexible mechanical sensing module, 31-Flexible mechanical sensor, 32-Signal conditioning circuit; 4-Wireless communication module; 5-Power supply module, 51-Lithium battery, 52-Inductively coupled power supply unit, 53-DC-DC converter; 6-Safety protection module. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can understand and implement it.

[0017] Example 1: A multi-channel isolated tongue muscle electrical stimulation system.

[0018] like Figure 1-4As shown, the system in this embodiment includes an intraoral stimulation module 1, a main control module 2, a flexible mechanical sensing module 3, a wireless communication module 4, a power supply module 5, and a safety protection module 6, with the specific configuration as follows: Intraoral stimulation module 1: includes a food-grade silicone substrate 12, on which two front electrodes 11 and two side electrodes 11 are disposed, for a total of four independent electrodes; the food-grade silicone substrate 12 is also provided with a shell 15, which covers the food-grade silicone substrate 12 and has an opening to expose the four electrodes; the module is equipped with a main control board 16 as the core hardware carrier, which integrates four H-bridge circuits 13 (the core unit of the drive circuit 14) and the functional circuits of the main control module 2, realizing arbitrary pairing of electrodes, supporting dynamic adjustment of the pairing mode per pulse cycle, and adapting to the tongue muscle training needs of different patients; Main control module 2: The MCU is a high-performance microcontroller, and the constant current control circuit 22 is composed of an operational amplifier and a feedback resistor. The current output range is 0-40mA and the error is ≤±2%. The digital isolator is a high-voltage model with an isolation voltage ≥2500Vrms to achieve reliable isolation between the main control and drive circuits. All of the above components are integrated on the main control board 16 of the intraoral stimulation module 1. Flexible mechanical sensing module 3: It adopts a resistive flexible sensor 31 (0.5mm thick) with a 0.3mm medical polyurethane film covering the surface, which has excellent biocompatibility; the signal conditioning circuit 32 amplifies the sensor signal and transmits it to the MCU with a sampling rate of 100Hz to ensure real-time signal acquisition. Wireless communication module 4: Bluetooth 5.0 BLE chip supports low power mode, communication latency ≤300ms, and battery life of 7 days on a single charge, meeting the needs of long-term daytime use; Power module 5: Lithium battery 51 with a capacity of 2000mAh, inductively coupled power supply unit 52 provides independent power supply for each electrode pair, DC-DC converter 53 outputs ±15V, realizing dual isolation between the electrodes and the main power domain, and compatible with plug-in and wireless usage scenarios; Safety Protection Module 6: The overcurrent protection circuit uses a high-precision current sensor, the overvoltage protection is implemented using a Zener diode, the insulation detection circuit has a detection threshold of 10MΩ, and the timeout protection is implemented through a hardware timer, comprehensively covering various safety risks.

[0019] Example 2: An integrated control method for a multi-channel isolated tongue muscle electrical stimulation system.

[0020] like Figure 5 As shown, the method in this embodiment is based on the system of embodiment 1, and the specific steps are as follows: Step 1: System Startup and Self-Test: After the device is started, the MCU detects the output status of the 4-channel drive circuit 14 (including the H-bridge circuit 13) through the digital isolator. If the current deviation of all channels is less than 5%, the channels are determined to be normal. A 1mV test voltage was applied to the flexible mechanical sensor 31, and the feedback signal was 1.02mV, indicating that the sensor was normal; the insulation resistance between the insulation detection electrode 11 and the substrate 12 was 15MΩ, which met the usage requirements; Step 2: Parameter Configuration: Users select the "Endurance Training" mode through the App, set the electrode pairing to alternate between 1-2 and 3-4, the current magnitude to 15mA, the pulse width to 100μs, the pulse period to 20Hz, and the total stimulation time to 20 minutes. After the parameters are transmitted to the MCU, the MCU completes the electrode pairing initialization through the H-bridge circuit 13. Step 3: Dynamic Stimulation and Sensory Feedback: The main control module 2 controls electrode pair 1-2 to output biphase constant current pulses, and switches to electrode pair 3-4 after 5 pulse cycles, alternating in a cycle to improve the training coverage of different areas of the tongue muscles. The flexible mechanical sensor 31 collects the tongue muscle contraction pressure signal in real time, amplifies it and transmits it to the MCU. When the pressure peak is detected to drop by 15%, the MCU controls the constant current circuit to fine-tune the current to 16mA to compensate for the reduction in training effect caused by tongue muscle fatigue. Step 4: Data Transmission and Exception Handling Every 5 seconds, the current electrode pairing method, current magnitude, pressure signal and other data are transmitted to the App, and users can view the training status in real time. During training, the device did not detect overcurrent, overvoltage, or insulation abnormalities and continued to complete the stimulation according to the set parameters. Five minutes before the end of training, the App issued a reminder, and the device automatically entered low-power mode after the training ended to reduce energy consumption.

[0021] The scope of protection of this invention is not limited to the above embodiments. For those skilled in the art, various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this invention. The scope of this invention is defined by the appended claims and their equivalents.

Claims

1. A multi-channel isolated tongue muscle electrical stimulation system, characterized in that: It includes an intraoral stimulation module, a main control module, a flexible mechanical sensing module, a wireless communication module, a power supply module, and a safety protection module; The intraoral stimulation module contains 4-8 independent electrodes, which are distributed in a matrix on a flexible biocompatible carrier. The intraoral stimulation module is equipped with a main control board, and each electrode corresponds to one drive circuit. The arbitrary pairing of electrodes and the reversal of current direction are realized through multiple H-bridge circuits. The main control module includes an MCU, a multi-channel constant current control circuit, and a digital isolator. The constant current control circuit consists of an operational amplifier and a feedback circuit, and the digital isolator realizes communication isolation between the main control unit and the drive circuit. The functional circuit of the main control module and the H-bridge circuit are integrated together on the main control board of the intraoral stimulation module. The flexible mechanical sensing module includes a flexible mechanical sensor and a signal conditioning circuit. The sensor is embedded in the intraoral stimulation module, and the signal conditioning circuit amplifies the sensor signal and transmits it to the MCU. The power module is battery powered and provides an independent power domain for each electrode pair through inductive coupling power supply, and is equipped with an isolated DC-DC converter; The wireless communication module uses Bluetooth or Wi-Fi to enable data interaction with a smartphone app; The safety protection module includes an overcurrent protection circuit, an overvoltage protection circuit, an insulation detection circuit, and a timeout protection circuit.

2. The multi-channel isolated tongue muscle electrical stimulation system according to claim 1, characterized in that: The threshold value of the overcurrent protection circuit is 40mA, the threshold value of the overvoltage protection circuit is 35V, the detection threshold value of the insulation detection circuit is 10MΩ, and the maximum duration of the timeout protection circuit is 30min.

3. The multi-channel isolated tongue muscle electrical stimulation system according to claim 1, characterized in that: The constant current control circuit has a current output range of 0-40mA, a current error of ≤±2%, and a pulse width of 50-500μs.

4. The multi-channel isolated tongue muscle electrical stimulation system according to claim 1, characterized in that: The flexible mechanical sensor is resistive or piezoelectric, and its surface is covered with a 0.1-0.5mm medical film.

5. The multi-channel isolated tongue muscle electrical stimulation system according to claim 1, characterized in that: The power module uses a battery and an isolated DC-DC converter outputting ±15V, achieving dual isolation between the electrodes and the main power domain.

6. An integrated control method for a multi-channel isolated tongue muscle electrical stimulation system, characterized in that: The system based on any one of claims 1-5 includes the following steps: Step 1: After the system starts up, the MCU performs a self-test of the electrode drive circuit, sensor, and insulation status. Step 2: The user selects a preset training mode through the App and transmits the electrode pairing method, current magnitude, pulse parameters, and total stimulation time to the MCU; Step 3: The MCU configures the target electrode pair through the H-bridge circuit and controls the constant current circuit to output bi-phase pulses, which can dynamically adjust the electrode pairing and current direction in each pulse cycle; Step 4: The flexible mechanical sensor collects the tongue muscle contraction signal in real time, amplifies it and transmits it to the MCU. The MCU dynamically fine-tunes the pulse current according to the changes in the tongue muscle contraction signal. Step 5: Transmit training data to the App in real time. If an abnormality is detected, immediately disconnect the stimulation of the corresponding electrode pair and trigger an alarm.

7. The integrated control method for a multi-channel isolated tongue muscle electrical stimulation system according to claim 6, characterized in that: In step 3, the pulse period can be adjusted within the range of 2-50Hz.

8. The integrated control method for a multi-channel isolated tongue muscle electrical stimulation system according to claim 6, characterized in that: In step 4, when the sensor detects a decrease in the peak pressure of tongue muscle contraction, the MCU will adjust the pulse current.

9. The integrated control method for a multi-channel isolated tongue muscle electrical stimulation system according to claim 6, characterized in that: In step 1, if the output current deviation of the electrode drive circuit is ≥5%, the channel will be disabled and a fault will be indicated via the App.

10. The integrated control method for a multi-channel isolated tongue muscle electrical stimulation system according to claim 6, characterized in that: In step 5, when the battery level is less than 20%, the user will be notified by sound and flashing lights to charge the battery in time.

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