Transcranial magnetoacoustic stimulation method and system based on PID closed loop feedback

Abstract

The invention discloses a transcranial magnetoacoustic stimulation method and a transcranial magnetoacoustic stimulation system based on PID closed loop feedback. The transcranial magnetoacoustic stimulation method comprises the following steps: acquiring a local field potential signal of a target brain region in real time as a feedback signal; preprocessing the feedback signal; inputting the preprocessed feedback signal into a PID controller, and generating a control signal for controlling the transcranial magnetoacoustic stimulation intensity through a PID control algorithm; and adjusting the stimulation intensity of transcranial magnetoacoustic stimulation according to the control signal.

Description

Technical Field

[0001] The present invention relates to the field of biomedicine, and in particular to a transcranial magnetic acoustic stimulation method and system based on PID closed-loop feedback. Background Art

[0002] With the development of medical technology, transcranial magnetic acoustic stimulation (TMAS) has been widely used in the treatment of depression, anxiety, cognitive impairment and other diseases. However, traditional transcranial magnetic acoustic stimulation has several shortcomings. First, due to the use of fixed stimulation frequency, intensity and duration, there is a lack of real-time adjustment mechanism, and it is impossible to make dynamic adjustments according to the patient's physiological feedback during the treatment process, which leads to unstable treatment effects and inability to flexibly respond to changes in the patient's physiological state or condition. Secondly, the fixed stimulation parameters cannot meet the individual differences of each patient, which may cause different patients to respond differently to the same parameters, and the treatment effect is difficult to be consistent. In addition, due to the inability to monitor the stimulation intensity in real time, there may be a risk of overstimulation, especially when the stimulation parameters do not meet the actual needs of the patient, thereby increasing the possibility of adverse reactions. The fundamental reason for the problems with traditional transcranial magnetic acoustic stimulation (TMAS) is that it lacks adaptability and real-time feedback mechanism, and cannot detect whether the stimulation is excessive or insufficient in time, which poses certain safety risks. Summary of the invention

[0003] To achieve the above-mentioned purpose and other related purposes, the present invention discloses a transcranial magnetic acoustic stimulation method based on PID closed-loop feedback, comprising: Real-time acquisition of local field potential signals in the target brain area as feedback signals; Preprocessing the feedback signal; The preprocessed feedback signal is input into a PID controller, and a control signal for controlling the intensity of transcranial magnetic acoustic stimulation is generated through a PID control algorithm; The stimulation intensity of transcranial magnetic acoustic stimulation was adjusted according to the control signal.

[0004] Furthermore, the collecting of local field potential signals of the target brain region includes: The data were collected by a microelectrode array at a frequency of 40 KHz.

[0005] Further, the preprocessing of the feedback signal includes: The feedback signal is filtered and amplified by a signal amplifier, the power spectrum density is calculated, and the proportion of the β frequency in the overall feedback signal is obtained.

[0006] Furthermore, the control signal for controlling the stimulation intensity of the transcranial magnetic acoustic stimulation unit generated by the PID control algorithm includes: Compare the proportion of the β frequency in the feedback signal in the overall feedback signal with a preset target value, and obtain an error value from the preset target value; Generate corresponding proportional gain, integral gain and differential gain respectively according to the error value; A control signal is generated based on the proportional gain, the integral gain, and the derivative gain.

[0007] Further, the step of generating corresponding proportional gain, integral gain and differential gain includes: Proportional gain: ; in is the real-time error value at time t, is a function related to the real-time error value, is the proportional factor corresponding to the proportional gain; Integral gain: ; in, is the proportional factor related to the integral gain; Differential gain: ; in, is the proportional factor related to the derivative gain.

[0008] Furthermore, the step of generating a control signal according to the proportional gain, the integral gain and the differential gain includes: The output of the discretized PID controller is: ; in: e[k] is the error value at the kth moment; Δt is the sampling time interval; , , It is the gain that is dynamically adjusted according to the sampling time k.

[0009] On the other hand, the present invention also provides a transcranial magnetic acoustic stimulation system based on PID closed-loop feedback, comprising: An acquisition module, used for real-time acquisition of local field potential signals of target brain areas as feedback signals; A preprocessing module, used for preprocessing the feedback signal; A PID feedback control module is used to input the preprocessed feedback signal into the PID controller, and generate a control signal for controlling the intensity of transcranial magnetic acoustic stimulation through a PID control algorithm; The transcranial magnetic acoustic stimulation module is used to receive control signals and change the magnetic stimulation intensity and the ultrasonic stimulation intensity in real time according to the control signals.

[0010] By adopting the above technical solution and using the PID control algorithm, the magnetic acoustic stimulation is adjusted in real time according to the feedback signal collected in real time, thereby reducing the risk of over-stimulation or under-stimulation and improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. The accompanying drawings are used to better understand the present solution and do not constitute a limitation of the present disclosure. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements, among which: Figure 1 Flowchart of this application. DETAILED DESCRIPTION

[0012] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0013] Reference Figure 1 The embodiment of the present invention provides a transcranial magnetic acoustic stimulation method based on PID closed-loop feedback, comprising the following steps: S1: Real-time acquisition of local field potential signals in the target brain area as feedback signals.

[0014] Specifically include: The local field potential signals of the target brain area were collected using a feedback acquisition unit, which included a microelectrode array and a signal amplifier. The microelectrode array consisted of 16 chromium-nickel microwire electrodes, the surface of which was covered with a layer of polyimide insulation and surrounded by polyethylene glycol for support and fixation. The electrodes were arranged in a 2×8 pattern, with a spacing of 250μm between electrodes and a single electrode diameter of 20μm. The signal amplifier used the Plexon-OmniPlex system to amplify, filter and convert the signal into a digital signal, which was collected at a frequency of 40KHz.

[0015] S2: Preprocess the feedback signal.

[0016] Specifically include: The feedback signal is filtered and amplified by a signal amplifier, the power spectrum density is calculated, and the proportion of the β frequency in the overall feedback signal is obtained.

[0017] As mentioned above, beta frequency oscillations (13–30 Hz) are closely related to normal brain function, motor control, and cognitive function. Abnormal behavior is significantly associated with the occurrence and development of a variety of neurological diseases. Parkinson's disease patients often show excessively synchronized beta oscillations, resulting in rigidity and bradykinesia. Abnormal beta waves in patients with epilepsy may be related to the onset and propagation of epileptic seizures. Schizophrenia patients have reduced beta oscillations in the prefrontal region, which may affect cognitive function. On the other hand, patients with depression often show increased prefrontal beta wave activity, which is associated with low mood. In Alzheimer's disease patients, weakened beta oscillations are associated with cognitive decline. In short, abnormal beta frequency oscillations reflect dysfunction in parts of the brain. These abnormalities are important markers for studying the pathological mechanisms of neurological diseases, as well as early diagnosis and treatment. Through real-time monitoring of the beta band frequency, the parameters of transcranial magnetic acoustic stimulation can be accurately adjusted, thereby achieving real-time control.

[0018] In this embodiment, the Welch method is used to solve the power spectrum density, which specifically includes: 1. Signal segmentation: Divide the original signal x(t) into several segments, each of length L. Each segment is an overlapping window, and the Hanning window function is used to reduce edge effects.

[0019] Assume that the signal length is N, and divide it into K segments, each of which has a length of L.

[0020] The signals overlap by 50% and the offset between each signal segment is L / 2.

[0021] 2. Window weighting: Apply a Hanning window function to each segment. The role of the window function is to reduce the discontinuity of the signal at the boundary of each segment and reduce the spectrum leakage phenomenon.

[0022] Assume that the kth segment signal is , then the signal after window weighting is: Where w(t) is the window function, which is symmetric and non-negative.

[0023] 3. Fourier transform: weighted signal for each segment Perform fast Fourier transform (FFT) to obtain the spectrum representation of the signal .

[0024] 4. Calculate the power spectrum: Calculate the power spectrum of the Fourier transform result of each segment to obtain the power value of each frequency point: 5. Average power spectrum: Average the power spectra of all segments to obtain the final power spectrum density estimate: Where K is the number of signal segments, is the power spectrum of the kth segment.

[0025] 6. Normalization: Finally, in order to obtain the power spectrum density within the unit frequency bandwidth, the result needs to be normalized. The power spectrum is appropriately scaled and divided by the energy of the window function.

[0026] S3: Input the preprocessed feedback signal into the PID controller, and generate a control signal for controlling the intensity of transcranial magnetic acoustic stimulation through the PID control algorithm.

[0027] Specifically include: S31: comparing the proportion of the β frequency in the feedback signal in the overall feedback signal with a preset target value, and obtaining an error value with the preset target value; S32: Generate corresponding proportional gain, integral gain and differential gain respectively according to the error value.

[0028] The steps to generate the corresponding proportional gain, integral gain, and derivative gain include: Proportional gain: ; in is the real-time error value at time t, is a function related to the real-time error value, is the proportional factor corresponding to the proportional gain; Integral gain: ; in, is the proportional factor related to the integral gain; Differential gain: ; in, is the proportional factor related to the derivative gain.

[0029] S33: Generate a control signal according to the proportional gain, the integral gain and the differential gain.

[0030] Specifically, when implementing adaptive PID control in a digital computer, the controller is usually discrete, and the output of the discretized PID controller is: ; in: e[k] is the error value at the kth moment; Δt is the sampling time interval; , , It is the gain that is dynamically adjusted according to the sampling time k.

[0031] S4: adjusting the stimulation intensity of transcranial magnetic acoustic stimulation according to the control signal.

[0032] As mentioned above, this embodiment adjusts the stimulation intensity of transcranial magnetic acoustic stimulation through a transcranial magnetic acoustic stimulation module. The transcranial magnetic acoustic stimulation module includes a magnetic stimulation module and an ultrasonic stimulation module. Sodium ions, potassium ions and chloride ions are the main types of free ions in neural tissue. When an ultrasonic wave perpendicular to the direction of the magnetic field is emitted in a static magnetic field environment, the charged ions vibrate along the propagation direction of the ultrasonic wave. At the same time, due to the Lorentz force in the magnetic field, the positive and negative ions move in opposite directions. This results in magnetoacoustic coupling current and magnetoacoustic coupling electric field, which affect the discharge activity of neurons (or neuronal clusters) and achieve the purpose of neural regulation.

[0033] The magnetic stimulation module consists of a Helmholtz coil, which consists of two concentric circular coils with the same radius R=0.2m and 1000 turns, and is spaced a certain distance apart. A very uniform magnetic field can be effectively generated, especially in the center area of ​​the two coils. The initial intensity of the magnetic field is set to 0.1T, and the magnetic field intensity of the transcranial magnetic stimulation part is precisely controlled by adjusting the current flowing through the coil.

[0034] At the center of the Helmholtz coil, the magnetic field strength B is approximately: in: B is the magnetic field strength (unit: Tesla, T).

[0035] is the magnetic permeability of vacuum (approximately 4π×10−7 T·m / A).

[0036] N is the number of turns in each coil.

[0037] I is the current through the coil.

[0038] R is the radius of each coil.

[0039] The ultrasonic stimulation module consists of an ultrasonic transmission power controller and a transducer. The transducer uses a 64-element planar transducer with an element width of 0.8 mm, an element spacing of 0.4 mm, and an element length of 4 mm. The ultrasonic fundamental frequency of the planar transducer is 500-1200 kHz, the pulse repetition frequency is 1.0 kHz, the number of pulse repetitions is 100, the number of fundamental wave cycles is 100, and the initial ultrasonic frequency is set to 800KHz. The ultrasonic intensity is controlled by adjusting the ultrasonic frequency through the ultrasonic transmission power controller.

[0040] By adopting the above technical solutions, the PID (proportional-integral-differential) control algorithm, as a widely used control method, can accurately adjust the intensity of the stimulation magnetic field and the intensity, frequency and duty cycle of ultrasound according to the local field potential signal monitored in real time in a closed-loop feedback system. Compared with the traditional simple feedback mechanism, PID control can effectively balance and optimize the response speed, stability and accuracy during the stimulation process to ensure that brain activity is optimally regulated. PID-TMAS uses the PID algorithm to adjust the stimulation parameters according to real-time feedback, and can dynamically regulate according to different stages of brain response (such as excitation period, inhibition period, etc.), thereby continuously optimizing the effect in different treatment cycles. Traditional closed-loop feedback systems may have problems with insufficient adjustment or slow response, while PID control can respond in real time and accurately adjust the stimulation output through precise proportional, integral and differential adjustments.

[0041] Transcranial magnetic acoustic stimulation (TMS-Audio Stimulation) based on PID closed-loop feedback has significant advantages over traditional transcranial magnetic acoustic stimulation, especially in terms of precise control and personalized treatment. Traditional transcranial magnetic acoustic stimulation usually relies on fixed parameter settings, such as stimulation intensity and frequency. These parameters remain unchanged throughout the treatment process and may not be able to adapt to the needs of different individuals or different treatment stages, thus affecting efficacy and safety. Transcranial magnetic acoustic stimulation based on PID closed-loop feedback can automatically adjust key parameters such as stimulation intensity, frequency, and duration according to the individual's real-time feedback by real-time monitoring and dynamic adjustment of stimulation parameters, thereby achieving more precise and personalized treatment.

[0042] Specifically, the PID closed-loop feedback system monitors the stimulation effect in real time, calculates the feedback error, and dynamically adjusts the output through the PID controller to ensure the maximum treatment effect. This control strategy enables the treatment process to adapt to individual differences, improves the targeted treatment, and avoids the discomfort or insufficient efficacy caused by excessive or insufficient stimulation intensity in traditional methods.

[0043] In addition, transcranial magnetic acoustic stimulation with PID closed-loop feedback can optimize parameters in real time during treatment, significantly improving the safety of treatment. In traditional methods, once the stimulation parameters are set, they are often difficult to adjust, which may cause unnecessary side effects to different patients. The feedback mechanism based on PID control can adjust the treatment plan in time to avoid excessive or weak stimulation and reduce the risk of adverse reactions.

[0044] In general, compared with traditional transcranial magnetic acoustic stimulation, transcranial magnetic acoustic stimulation based on PID closed-loop feedback not only improves the accuracy and personalization of treatment, but also enhances safety. It can better meet the needs of different patients and provide a more optimized treatment experience.

[0045] An embodiment of the present invention further provides a system, comprising: An acquisition module, used for real-time acquisition of local field potential signals of target brain areas as feedback signals; A preprocessing module, used for preprocessing the feedback signal; A PID feedback control module is used to input the preprocessed feedback signal into the PID controller, and generate a control signal for controlling the intensity of transcranial magnetic acoustic stimulation through a PID control algorithm; The transcranial magnetic acoustic stimulation module is used to receive control signals and change the magnetic stimulation intensity and the ultrasonic stimulation intensity in real time according to the control signals.

[0046] Those skilled in the art will appreciate that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined.

[0047] For the method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the embodiments of the present invention are not limited by the order of the actions described, because according to the embodiments of the present invention, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present invention.

[0048] It can be known from the description of the above implementation modes that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present application can be essentially or partly contributed to the prior art in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes several instructions for enabling a computer device (which can be a personal computer, a server or a network device, etc.) to execute the methods described in the various implementation modes of the present application or certain parts of the implementation modes.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A transcranial magnetic acoustic stimulation method based on PID closed-loop feedback, characterized in that: include: Real-time acquisition of local field potential signals in the target brain area as feedback signals; Preprocessing the feedback signal; The preprocessed feedback signal is input into a PID controller, and a control signal for controlling the intensity of transcranial magnetic acoustic stimulation is generated through a PID control algorithm; The stimulation intensity of transcranial magnetic acoustic stimulation was adjusted according to the control signal.

2. The method according to claim 1, characterized in that The collecting of the local field potential signal of the target brain area comprises: The data were collected by a microelectrode array at a frequency of 40 KHz.

3. The method according to claim 1, characterized in that The preprocessing of the feedback signal comprises: The feedback signal is filtered and amplified by a signal amplifier, the power spectrum density is calculated, and the proportion of the β frequency in the overall feedback signal is obtained.

4. The method according to claim 1, characterized in that The control signal for controlling the stimulation intensity of the transcranial magnetic acoustic stimulation unit generated by the PID control algorithm comprises: Compare the proportion of the β frequency in the feedback signal in the overall feedback signal with a preset target value, and obtain an error value from the preset target value; Generate corresponding proportional gain, integral gain and differential gain respectively according to the error value; A control signal is generated based on the proportional gain, the integral gain, and the derivative gain.

5. The method according to claim 4, characterized in that The step of generating corresponding proportional gain, integral gain and differential gain comprises: Proportional gain: ； in is the real-time error value at time t, is a function related to the real-time error value, is the proportional factor corresponding to the proportional gain; Integral gain: ； in, is the proportional factor related to the integral gain; Differential gain: ； in, is the proportional factor related to the derivative gain.

6. The method according to claim 5, characterized in that The step of generating a control signal according to the proportional gain, the integral gain and the differential gain comprises: The output of the discretized PID controller is: ； in: e[k] is the error value at the kth moment; Δt is the sampling time interval; , , It is the gain that is dynamically adjusted according to the sampling time k.

7. A transcranial magnetic acoustic stimulation system based on PID closed-loop feedback, characterized in that: include: An acquisition module, used for real-time acquisition of local field potential signals of target brain areas as feedback signals; A preprocessing module, used for preprocessing the feedback signal; A PID feedback control module is used to input the preprocessed feedback signal into the PID controller, and generate a control signal for controlling the intensity of transcranial magnetic acoustic stimulation through a PID control algorithm; The transcranial magnetic acoustic stimulation module is used to receive control signals and change the magnetic stimulation intensity and the ultrasonic stimulation intensity in real time according to the control signals.

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