An implantable medical device pulse stimulation system, method, and implantable medical device

Abstract

The application provides a pulse stimulation system and method of an implantable medical device and the implantable medical device. The signal acquisition and processing module acquires an electrical signal collected by an implantable pulse generator through any one or more electrodes, and performs frequency domain transformation on the electrical signal to obtain a frequency domain signal. The trigger condition determination module responds to a confirmation instruction of a program control device, locks a target frequency band according to the frequency domain signal, and configures a target phase trigger condition corresponding to the target frequency band. The phase prediction module predicts a future time sequence signal based on the electrical signal of the target frequency band, and generates phase prediction information according to the future time sequence signal. The pulse emission module determines stimulation emission decision information according to the phase prediction information and the target phase trigger condition, so that the electrode emits pulses according to the stimulation emission decision information, solves the problems of insufficient microscopic time sequence intervention, high energy consumption and easy deviation of trigger timing in the prior art, and realizes low-power, anti-interference and precise time sequence stimulation.

Description

Technical Field

[0001] This invention relates to the field of neuromodulation technology, and more particularly to a pulse stimulation system, method, and implantable medical device. Background Technology

[0002] Currently, with the widespread application of deep brain stimulation technology in the treatment of movement disorders such as Parkinson's disease, the research focus in the field of neuromodulation has gradually shifted from simple open-loop continuous stimulation to closed-loop adaptive modulation based on neurophysiological signals in the brain.

[0003] Currently, the closest existing technologies mainly fall into two categories: one adjusts stimulation parameters by analyzing signal intensity characteristics, and the other triggers pulse delivery by tracking the position of the signal waveform in real time. The main drawbacks of these approaches are: the first can only reflect macroscopic statistical trends and cannot achieve precise intervention at the scale of a single waveform; the second requires continuous high-load operation, resulting in excessive energy consumption, and processing delays and signal interference cause the actual triggering timing to deviate from the target, making it difficult to meet the long-term operational requirements of implantable devices. Summary of the Invention

[0004] This application provides a pulse stimulation system, method, and implantable medical device to address the problems of insufficient microscopic timing intervention, excessive energy consumption, and easy deviation of triggering timing in the prior art, thereby achieving low-power, interference-resistant, and precise timing stimulation.

[0005] In a first aspect, embodiments of this application also provide a pulse stimulation system for an implantable medical device, the device comprising: The signal acquisition and processing module is used to acquire electrical signals collected by the implantable pulse generator through any one or more electrodes, and to perform frequency domain transformation on the electrical signals to obtain frequency domain signals. The trigger condition determination module is used to respond to the confirmation command of the programmable device, lock the target frequency band according to the frequency domain signal, and configure the target phase trigger condition corresponding to the target frequency band; A phase prediction module is used to predict future timing signals based on the electrical signals in the target frequency band, and to generate phase prediction information based on the future timing signals. The pulse delivery module is used to determine stimulus delivery decision information based on phase prediction information and the target phase triggering condition, so that any one or more electrodes deliver pulses according to the stimulus delivery decision information; wherein, when the pulse delivery module delivers pulses, the signal acquisition module is in a non-acquisition state.

[0006] Furthermore, the trigger condition determination module is specifically used for: the programmable device to identify the characteristic frequency in the frequency domain signal according to the built-in algorithm, lock the target frequency band, configure the target phase trigger condition corresponding to the target frequency band, and generate a confirmation command.

[0007] Furthermore, the trigger condition determination module is also specifically used to: display the frequency domain signal and the target frequency band that can be locked through the visual interface of the programmable device for review and confirmation; display and provide configurable phase trigger conditions through the visual interface of the programmable device for review and confirmation; and generate a confirmation command in response to the manual review and confirmation operation of the programmable device.

[0008] Furthermore, the trigger condition determination module is specifically used to: after the programmable device locks the target frequency band and configures the target phase trigger condition according to the built-in algorithm, display the target frequency band and the target phase trigger condition through the visualization interface of the programmable device; in response to the manual review and confirmation operation of the programmable device, modify the target frequency band and / or the target phase trigger condition, so as to generate a confirmation command based on the modification result.

[0009] Furthermore, the phase prediction information includes a future phase timetable, and the phase prediction module is specifically used to: filter the acquired electrical signal based on the target frequency band to obtain a target oscillation signal; input the target oscillation signal into a time-series prediction model to determine the future time-series signal; and extract the future phase based on the future time-series signal to generate a future phase timetable.

[0010] Furthermore, the pulse delivery module is specifically used to: select a time point in the phase prediction information that satisfies the target phase triggering condition, and form a stimulation delivery schedule from the time points; and control the implanted pulse generator to deliver pulses to any one or more electrodes according to the stimulation delivery schedule.

[0011] Furthermore, the system is also configured to: wake up the signal acquisition module of the implantable pulse generator and turn off the pulse delivery module according to a preset cycle; acquire the current electrical signal through any one or more electrodes; determine the current actual phase characteristics based on the current electrical signal; determine the phase error based on the current actual phase characteristics and the phase of the corresponding time in the phase prediction information; when the phase error is less than or equal to a preset tolerance threshold, refresh the stimulus delivery decision information based on the current electrical signal, turn off the signal acquisition module and turn on the pulse delivery module; when the phase error is greater than the preset tolerance threshold, exit the preset cycle wake-up strategy, control the implantable pulse generator to switch to the safety bottom line mode, and send a warning signal to the programmable device.

[0012] Furthermore, the preset period is set to different periods for different time periods.

[0013] Furthermore, if the cumulative phase difference is less than or equal to the cumulative threshold within a preset time period, the preset period is increased by a preset step size; if the cumulative phase difference is greater than the cumulative threshold within the preset time period, the preset period is decreased by a preset step size.

[0014] Furthermore, the safety baseline mode is that the implanted pulse generator controls any one or more electrodes to deliver preset pulses, entering an open-loop stimulation mode.

[0015] Secondly, embodiments of this application also provide a pulse stimulation method for an implantable medical device, the method comprising: The signal acquisition and processing module acquires the electrical signals collected by the implantable pulse generator through any one or more electrodes, and performs frequency domain transformation on the electrical signals to obtain frequency domain signals. In response to the confirmation command from the programmable control device, the trigger condition determination module locks the target frequency band based on the frequency domain signal and configures the target phase trigger condition corresponding to the target frequency band. The phase prediction module predicts future timing signals based on the electrical signals in the target frequency band, and generates phase prediction information based on the future timing signals. The pulse delivery module determines the stimulus delivery decision information based on the phase prediction information and the target phase triggering condition, so that any one or more electrodes deliver pulses according to the stimulus delivery decision information; wherein, when the pulse delivery module delivers pulses, the signal acquisition module is in a non-acquisition state.

[0016] Furthermore, the method further includes: waking up the signal acquisition module of the implantable pulse generator and shutting down the pulse delivery module according to a preset cycle, and acquiring the current electrical signal through any one or more electrodes; wherein the preset cycle is set with different cycles for different time periods; determining the current actual phase characteristics based on the current electrical signal; determining the phase error based on the current actual phase characteristics and the phase of the corresponding time in the phase prediction information; when the phase error is less than or equal to a preset tolerance threshold, refreshing the stimulus delivery decision information based on the current electrical signal, shutting down the signal acquisition module and turning on the pulse delivery module; when the phase error is greater than the preset tolerance threshold, exiting the preset cycle wake-up strategy, controlling the implantable pulse generator to switch to the safety bottom line mode, and sending a warning signal to the programmable device.

[0017] Thirdly, embodiments of this application also provide an implantable medical device, which includes at least a pulse generator implanted in the body of a target subject and an electrode wire implanted in the brain of the target subject. The implanted end of the electrode wire is provided with at least one or more electrodes, and the pulse generator is connected to the electrode wire. The pulse generator includes: The signal acquisition and processing module unit is used to acquire electrical signals acquired through any one or more electrodes, and to perform frequency domain transformation on the electrical signals to obtain frequency domain signals. The communication unit is used to receive confirmation commands from the programmable control equipment. A parameter configuration unit is used to respond to the confirmation command, lock the target frequency band according to the frequency domain signal, and configure the target phase triggering conditions corresponding to the target frequency band; A phase prediction unit is used to predict future timing signals based on the electrical signals in the target frequency band, and to generate phase prediction information based on the future timing signals. A pulse control unit is used to determine stimulus delivery decision information based on phase prediction information and the target phase triggering condition, so that any one or more electrodes deliver pulses according to the stimulus delivery decision information, wherein when the pulse delivery module delivers pulses, the signal acquisition module is in a non-acquisition state.

[0018] This application provides a pulse stimulation system for an implantable medical device. A signal acquisition and processing module acquires electrical signals collected by an implantable pulse generator through one or more electrodes, and performs frequency domain transformation on the electrical signals to obtain frequency domain signals. A trigger condition determination module responds to a confirmation command from a programmable device, locks a target frequency band based on the frequency domain signals, and configures target phase trigger conditions corresponding to the target frequency band. A phase prediction module predicts future timing signals based on the electrical signals of the target frequency band and generates phase prediction information based on the future timing signals. A pulse delivery module determines stimulation delivery decision information based on the phase prediction information and the target phase trigger conditions, so that one or more electrodes deliver pulses according to the stimulation delivery decision information. When the pulse delivery module delivers pulses, the signal acquisition module is in a non-acquisition state. The technical effects of this application's solution are as follows: First, a flexible and secure trigger condition configuration mechanism: Upon initial power-on, the target frequency band and corresponding phase trigger conditions can be locked through manual confirmation, automatic algorithm confirmation, or a combination of both. Manual intervention ensures clinical safety and individualized adaptation, algorithm assistance improves efficiency and objectivity, and the combination of both balances flexibility and reliability.

[0019] Second, precise phase locking based on prediction models: the phase prediction module predicts the future timing of the electrical signal in the target frequency band and generates phase prediction information, thereby predicting the optimal phase timing before stimulation is delivered. This can overcome signal transmission and processing delays, significantly improve phase alignment accuracy, ensure that each pulse falls within the preset phase window, and improve the consistency of stimulation efficacy.

[0020] Third, the system power consumption is reduced through multi-level energy-saving design: On the one hand, the signal acquisition module is in a non-acquisition state during pulse emission, which avoids interference from stimulus artifacts and reduces the energy consumption of invalid acquisition; on the other hand, it can perform intermittent acquisition based on a preset wake-up cycle, and can dynamically adjust the wake-up interval according to the cumulative prediction error, thereby extending the sleep time when the error is small and encrypting the acquisition when the error increases, which not only ensures the tracking effectiveness, but also further optimizes the overall power consumption and extends the service life of the implanted device.

[0021] Fourth, the flexible and adjustable stimulation strategy can adapt to the patient's circadian rhythm: the acquisition and arousal cycle and stimulation parameters are dynamically adjusted according to the user's daily routine (such as the active period during the day and the resting period at night) to achieve a differentiated treatment mode between day and night. This adjustable cycle mechanism matches the treatment intensity with the patient's physiological state, improves comfort and adaptability, and avoids excessive or insufficient stimulation caused by fixed parameters.

[0022] Fifth, closed-loop control and safety assurance, balancing efficacy and risk control: By monitoring electrical signal errors in real time, subsequent stimulation decision information is dynamically adjusted, forming a closed-loop control link of perception, prediction, stimulation, and evaluation. This ensures that stimulation is always anchored to the target phase, thereby maintaining long-term stable therapeutic effects. Simultaneously, when prediction errors or signal deviations exceed preset safety thresholds, alarms can be issued promptly or stimulation can be actively paused to prevent ineffective or biased stimulation from causing potential harm to patients, effectively ensuring clinical safety. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the exemplary embodiments of this application, the accompanying drawings used in describing the embodiments are briefly introduced below. Obviously, the accompanying drawings described are only a portion of the embodiments to be described in this application, and not all of them. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of a pulse stimulation system for an implantable medical device provided in an embodiment of the present invention; Figure 2 A schematic diagram illustrating the implementation process of a pulse stimulation system for another implantable medical device provided in this application embodiment; Figure 3A schematic diagram illustrating the implementation process of a pulse stimulation system for another implantable medical device provided in this application embodiment; Figure 4 A schematic diagram illustrating the implementation process of a pulse stimulation system for another implantable medical device provided in this application embodiment; Figure 5 A schematic flowchart illustrating a pulse stimulation method for an implantable medical device provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of an implantable medical device provided in an embodiment of this application. Detailed Implementation

[0025] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present application, not the entire structure.

[0026] Before introducing the technical solution provided in the embodiments of this application, the application scenarios of the solution can be described first. This embodiment is applicable to various scenarios that require closed-loop neuromodulation of neurophysiological signals in the brain. Currently, although adaptive closed-loop stimulation based on signal intensity characteristics or phase-locked stimulation based on real-time phase tracking has been explored in scientific research and clinical practice, traditional methods have obvious limitations. In practical applications, due to the non-stationarity, strong noise, and large individual differences of neural electrical signals, and the multiple engineering constraints of implantable devices such as size, power consumption, and signal acquisition interference, traditional modulation methods are difficult to achieve precise intervention at the micro-temporal level, which can easily lead to problems such as misalignment of stimulation timing and target phase, excessive device energy consumption, and insufficient long-term operational stability. Therefore, there is an urgent need for a modulation method that can get rid of dependence on continuous signal acquisition and take into account both temporal accuracy and system energy efficiency, so as to improve the accuracy and implantability of closed-loop stimulation.

[0027] Example 1 The technical solution provided by this invention is mainly applied to the field of implantable medical devices. The implantable medical device mainly includes a pulse generator and electrode leads. The pulse generator is implanted into the patient's body (e.g., the chest cavity, skull, etc.). The electrode leads are connected to the pulse generator subcutaneously at one end, and a stimulation electrode is disposed at the other end. The stimulation electrode includes at least one metal contact that outputs a stimulation source. These metal contacts can be annular or directional electrodes composed of multiple segmented electrode contacts. The stimulation electrode is partially implanted at a designated location in the patient's brain (e.g., nuclei or neural tissue associated with the disease). The doctor sends programmed parameters to the pulse generator through a programming device. The pulse generator delivers electrical stimulation to at least one metal contact in the stimulation electrode through the electrode leads, causing the at least one metal contact to generate an electric field, thereby treating the corresponding disease.

[0028] Figure 1 This is a schematic diagram of a pulse stimulation system for an implantable medical device provided in an embodiment of this application. This embodiment can be applied to various situations that require closed-loop neural modulation of neurophysiological signals in the brain. The device can be implemented in the form of software and / or hardware. The hardware can be a controller, such as a mobile terminal, a PC, or a server.

[0029] like Figure 1 As shown, the pulse stimulation system of the implantable medical device provided in this embodiment of the invention includes: 110. Signal acquisition and processing module, used to acquire electrical signals collected by the implantable pulse generator through any one or more electrodes, and to perform frequency domain transformation on the electrical signals to obtain frequency domain signals.

[0030] An implantable pulse generator refers to a device implanted in the body of a target individual to generate and emit electrical stimulation pulses. The electrical signal refers to the raw signal of the local field potential collected by the implantable pulse generator from the brain or other relevant tissues of the target individual via electrodes; this signal carries information about the collective electrical activity of neurons.

[0031] Frequency domain signal refers to the signal representation obtained after frequency domain transformation of the acquired electrical signal. By converting the original time-domain electrical signal into spectral distribution information with frequency as the independent variable, the energy or power characteristics of the electrical signal at different frequency components can be revealed.

[0032] Specifically, before or during closed-loop neuromodulation of the target subject, an implantable pulse generator, through electrodes connected to and deployed at specific target points in the target subject's brain, passively senses or actively acquires raw signals of local field potentials. These electrical signals reflect the synchronized electrical activity and rhythmic oscillations of the neuronal population surrounding the electrodes. To extract frequency features usable for modulation decisions from these electrical signals, a frequency domain transformation operation can be performed on the acquired signals. This transforms the signals from a time-domain representation that varies with time to a frequency-domain representation that is distributed according to frequency. The resulting frequency domain signal clearly shows the energy distribution of the electrical signal at different frequency positions, allowing for the identification of specific oscillation frequency bands with significant physiological or pathological relevance. This provides quantitative spectral basis for locking the target frequency band and configuring corresponding phase triggering conditions.

[0033] 120. Trigger condition determination module, used to respond to the confirmation command of the programmable control equipment, lock the target frequency band according to the frequency domain signal, and configure the target phase trigger condition corresponding to the target frequency band.

[0034] In this context, "programmable control equipment" refers to an externally programmed control device operated by clinicians or professional technicians. This equipment communicates wirelessly with the implanted pulse generator to send control parameters, receive collected data, and display signal analysis results. It serves as the host computer terminal for human-machine interaction and parameter configuration within the entire control system. "Confirmation command" refers to a deterministic command signal used to ultimately lock onto the target frequency of the control system.

[0035] The target frequency band refers to the specific frequency range in which phase prediction and pulse intervention need to be implemented, and this frequency band can correspond to the neural oscillation rhythm associated with the pathological state.

[0036] The target phase triggering condition refers to the timing criterion for electrical pulse delivery based on the oscillation waveform characteristics of the target frequency band. The target phase triggering condition specifies that the stimulus pulse should be released at a specific phase position of the oscillation cycle to achieve precise timing of neural modulation.

[0037] Specifically, after the programmable device completes spectrum analysis and displays relevant spectrum information, the operator can issue a confirmation command based on clinical judgment. Receiving this confirmation command triggers the subsequent parameter locking and configuration process. Specifically, a specific frequency range associated with pathological neural oscillations can be determined from the spectrum distribution displayed by the frequency domain signal; this range is locked as the target frequency band. This locking action references both objective data from the frequency domain signal and incorporates the human selection intent carried by the confirmation command. Based on the clearly defined target frequency band, further phase correlation criteria are set for the oscillation waveform characteristics corresponding to this target frequency band, i.e., configuring the target phase trigger condition corresponding to the target frequency band. This trigger condition specifies the phase position of the stimulation pulse in the oscillation cycle at which it should be output, thereby ensuring that the subsequently emitted pulses can accurately match the rhythmic characteristics of the target frequency band in timing.

[0038] 130. Phase prediction module, used to predict future timing signals based on electrical signals in the target frequency band, and generate phase prediction information based on the future timing signals.

[0039] In this context, the future time series signal refers to the predicted sequence generated by a prediction algorithm, which anticipates the future trend of the electrical signal over time. The future time series signal characterizes the amplitude or state change trend of the target frequency band oscillation signal that has not yet occurred on the subsequent time axis.

[0040] Phase prediction information refers to a set of information used to describe the phase state of a target frequency band signal at a future time. This information reflects the phase value or phase interval corresponding to the prediction time point.

[0041] Specifically, after identifying the target frequency band and obtaining the corresponding electrical signal, these signals can be used to deduce the subsequent signal evolution that has not yet occurred. The specific method involves using a built-in predictive computing mechanism, based on the historical variation patterns of the electrical signal in the target frequency band, to calculate how the signal will continue to fluctuate over time in the future. The resulting prediction is the future time-series signal.

[0042] After obtaining the future time-series signal, it is necessary to analyze the specific phase position within the oscillation period of the signal at each future time point. This phase information is then arranged in a one-to-one correspondence with the corresponding time points, forming a phase comparison record organized chronologically. This record is the phase prediction information. Through this process, the abstract future time-series signal is transformed into a directly queryable correspondence between phase and time, providing clear time coordinates for subsequently determining when the phase conditions for pulse emission are met.

[0043] 140. Pulse delivery module, used to determine stimulus delivery decision information based on phase prediction information and target phase triggering conditions, so that any one or more electrodes can deliver pulses according to the stimulus delivery decision information.

[0044] Among them, the stimulus delivery decision information refers to the set of control instructions determined after comparing or matching the phase prediction information with the preset target phase triggering conditions, regarding whether to deliver a pulse, and the electrode configuration and pulse parameters that should be associated with the delivery pulse. This decision information is directly used to drive any one or more electrodes to perform pulse delivery actions.

[0045] Specifically, the phase prediction information provides the instantaneous phase information of the target frequency band oscillation signal corresponding to each future moment. Simultaneously, the target phase triggering conditions have already been configured, specifying the exact phase positions of the pulse output within the oscillation cycle. Therefore, each future moment listed in the phase prediction information and its corresponding phase information needs to be compared and judged against the pre-set target phase triggering conditions. Only when the phase information of a future moment falls within or matches the phase range required by the triggering condition is that moment considered to meet the timing requirements for pulse delivery. All these future moments that meet the conditions are selected and arranged chronologically to form a timing execution plan that clearly defines the specific moments for each pulse delivery; this plan is the stimulus delivery decision information. After the stimulus delivery decision information is determined, the implanted pulse generator outputs electrical pulses through any one or more electrodes at each specified moment according to the time sequence specified in the stimulus delivery decision information, thereby ensuring that the pulse delivery timing is precisely locked at the target phase position of the target frequency band oscillation cycle.

[0046] In this embodiment, the signal acquisition module is in a non-acquisition state when the pulse delivery module delivers a pulse. It should be noted that this embodiment is applied to the scenario of the system's initial use. This can be understood as follows: during the initial power-on process of this embodiment, the programmable device first controls the signal acquisition module to acquire electrical signals. After completing the initial configuration and starting pulse delivery, it actively shuts off the signal acquisition paths of all electrode channels, stopping the sampling, amplification, and buffering of electrical signals, thus placing the signal acquisition module in a non-acquisition state during pulse delivery. The purpose of this design is to reduce system power consumption, i.e., to avoid the ineffective energy consumption generated by the continuous operation of the acquisition circuit during pulse output, thereby achieving energy-saving optimization during the power-on initialization phase and extending the overall battery life of the implantable device.

[0047] This application provides a pulse stimulation system for an implantable medical device. In the scenario of the system's first use, a signal acquisition and processing module acquires electrical signals collected by an implantable pulse generator through any one or more electrodes, and performs frequency domain transformation on the electrical signals to obtain frequency domain signals. A trigger condition determination module responds to the confirmation command of the programmable device, locks the target frequency band according to the frequency domain signal, and configures the target phase trigger condition corresponding to the target frequency band. A phase prediction module predicts future timing signals based on the electrical signals of the target frequency band and generates phase prediction information based on the future timing signals. A pulse delivery module determines stimulation delivery decision information based on the phase prediction information and the target phase trigger condition, so that any one or more electrodes deliver pulses according to the stimulation delivery decision information. When the pulse delivery module delivers pulses, the signal acquisition module is in a non-acquisition state. The technical solution of this application accurately locks the target frequency band through frequency domain transformation and, combined with manual confirmation of the phase triggering conditions, lays the foundation for precise stimulation. It utilizes a predictive model to extrapolate the future timing of the target frequency band signal, predicting the optimal stimulation phase in advance, effectively overcoming system transmission and processing delays, and ensuring that the pulse is accurately anchored to the predetermined phase window, thereby significantly improving treatment consistency. Simultaneously, the system actively pauses acquisition during pulse delivery to avoid ineffective power consumption, further extending the device's battery life while ensuring tracking effectiveness. This achieves a synergistic optimization of high precision and low energy consumption, solving the problem of existing solutions being unable to accurately intervene at the single waveform scale and causing excessive energy consumption due to continuous real-time tracking. This improves stimulation accuracy and reduces operational burden.

[0048] Example 2 Figure 2 This is a schematic diagram illustrating the implementation process of a pulse stimulation system for an implantable medical device provided in this application. Based on the foregoing embodiments, this embodiment will provide a detailed description of the trigger condition determination module. For specific implementation details, please refer to the technical solution of this embodiment. Technical terms that are the same as or corresponding to those in the above embodiments will not be repeated here.

[0049] like Figure 2 As shown, the specific steps include the following: S210. Send acquisition commands to the implantable pulse generator through the programmable control equipment, and control the implantable pulse generator to acquire local field potential signals of the target brain tissue through any one or more electrodes.

[0050] Among them, the acquisition command refers to the control command issued by the programmable device to the implantable pulse generator to trigger the implantable pulse generator to start the electrode signal pickup operation.

[0051] Among them, the local field potential signal refers to the low-frequency electrophysiological signal that reflects the sum of the synaptic activity of local neuronal groups and dendritic potentials, collected from the brain tissue of the target object through electrodes.

[0052] In the initial stage of the neuromodulation process, a programmable device acts as the higher-level control unit, sending a data acquisition command to an implantable pulse generator implanted in the target body via a wireless communication link. This command carries a clear control intention to initiate signal acquisition. Upon receiving the acquisition command, the implantable pulse generator immediately activates its front-end sensing pathway and, using any one or more electrodes attached to the end of its connected electrode wires, begins to acquire local field potential signals from the target brain tissue region.

[0053] S220. Perform frequency domain transformation on the local field potential signal to obtain the frequency domain signal.

[0054] S230, the programmable device, based on its built-in algorithm, identifies the characteristic frequencies in the frequency domain signal, locks the target frequency band, configures the target phase triggering conditions corresponding to the target frequency band, and generates a confirmation command.

[0055] The target frequency band refers to the specific frequency range that is locked and confirmed from the frequency domain signal and used for subsequent phase prediction and pulse modulation.

[0056] Specifically, the programmable control equipment, acting as the upper-level control terminal, uses pre-embedded algorithms to analyze and process the frequency domain signal. This algorithm automatically scans the spectral distribution of the signal and identifies characteristic frequencies with significantly prominent amplitudes or power. These characteristic frequencies often correspond to physiologically or pathologically significant neural oscillation rhythms. Based on the identification of these characteristic frequencies, the programmable control equipment further selects a suitable frequency range from these frequencies according to clinical control goals, locking it as the target frequency band as the frequency domain reference for subsequent phase prediction and pulse control.

[0057] After locking onto the target frequency band, the programmable controller can also set the timing criteria for the electrical pulse delivery based on the oscillation waveform characteristics corresponding to the target frequency band. This involves configuring the target phase trigger condition corresponding to the target frequency band, which specifies the phase position of the pulse output within the oscillation period. Throughout the process of locking onto the target frequency band and configuring the target phase trigger condition, the programmable controller integrates the processing results of each step and the final determined parameters to generate a confirmation command. This confirmation command carries complete parameter configuration information calculated and filtered by the built-in algorithm, for subsequent issuance or for operator review and confirmation.

[0058] After completing the frequency domain signal analysis and initial target frequency band locking, and configuring the corresponding target phase triggering conditions, a human-machine collaborative review and confirmation process is needed to ensure that the control parameters conform to both the objective screening results of the algorithm and the professional judgment of clinicians. Specifically, this includes the following steps: displaying the frequency domain signal and the target frequency band to be locked through the visual interface of the programmable device for review and confirmation; displaying the configurable phase triggering conditions through the visual interface of the programmable device for review and confirmation; and generating a confirmation command in response to the manual review and confirmation operation of the programmable device.

[0059] Specifically, the programmable controller (PCC) visually displays the overall spectral distribution of the frequency domain signal and the target frequency bands that can be locked through its interface. This interface also provides configurable phase trigger condition options for operators to review and adjust based on clinical experience. In response to the operator's manual review and confirmation via this interface, a confirmation command is generated. This visual review and manual confirmation mechanism integrates clinicians' experience with automated algorithm recognition, effectively improving the accuracy and clinical suitability of target frequency band locking and phase trigger condition configuration. It also reduces the risk of pure algorithmic misjudgment or deviation from the effective control target due to signal artifacts, and enhances the operator's sense of control and trust in the entire control parameter setting process.

[0060] To further improve the clinical suitability and safety of neuromodulation, this method adds a human-machine collaborative review step before generating the final confirmation instruction. In this embodiment, optionally, after the programmable device locks the target frequency band and configures the target phase triggering conditions according to its built-in algorithm, the target frequency band and target phase triggering conditions are displayed through the programmable device's visual interface; in response to the programmable device's manual review and confirmation operation, the target frequency band and / or target phase triggering conditions are corrected, and a confirmation instruction is generated based on the correction result.

[0061] Specifically, as another implementation method, after the programmable device locks the target frequency band and configures the target phase triggering conditions according to the built-in algorithm, it does not directly use the result as the final control basis. Instead, it first displays the locked target frequency band and the configured target phase triggering conditions through the programmable device's visual interface, allowing clinicians to intuitively verify the algorithm output in conjunction with the patient's actual condition or clinical experience. When clinicians perform manual review and confirmation through this visual interface, if they believe that the target frequency band locked by the algorithm is not accurate enough or the configured target phase triggering conditions do not meet the current treatment needs, they have the right to adjust or correct any one or both of the target frequency band or target phase triggering conditions. The programmable device only uses the corrected result as the basis for generating the final confirmation instruction. This process ensures that the final confirmation instruction used for subsequent phase prediction and stimulus decision-making incorporates both the objective screening capability of the built-in algorithm and the professional judgment of the clinician, thereby improving the clinical rationality and individual adaptability of target frequency band locking and phase triggering condition configuration.

[0062] S240: In response to the confirmation command from the programmable control equipment, lock the target frequency band according to the frequency domain signal, and configure the target phase triggering condition corresponding to the target frequency band.

[0063] S250: Predict future timing signals based on electrical signals in the target frequency band, and generate phase prediction information based on the future timing signals.

[0064] S260. Determine stimulus delivery decision information based on phase prediction information and target phase triggering conditions, so that any one or more electrodes can deliver pulses according to the stimulus delivery decision information.

[0065] The technical solution of this application embodiment, when acquiring the electrical signal collected by the implantable pulse generator through the electrodes, sends a collection command to the implantable pulse generator through a programmable control device to control its collection of local field potential signals. This method realizes the active triggering and remote scheduling of the signal acquisition action of the implantable pulse generator by the upper control terminal, so that the start time and duration of signal acquisition can be controlled by the operator as needed. At the same time, it also ensures that the source of the collected local field potential signal is clear and points to a specific combination of electrode contacts, providing standardized raw data input for subsequent frequency domain analysis, thereby improving the controllability and consistency of signal acquisition in the entire control process.

[0066] In response to a confirmation command from a programmable device, the programmable device identifies characteristic frequencies in the frequency domain signal, locks the target frequency band, and configures the target phase triggering conditions corresponding to the target frequency band, generating a confirmation command. This process enables the selection of the target frequency band and the configuration of the phase triggering conditions to be automatically completed based on the objective quantitative analysis of the frequency domain signal using an algorithm, reducing the workload of manually interpreting the spectrum and manually setting parameters. At the same time, by centrally processing the identification, locking, and configuration steps at the programmable device end and integrating them into a confirmation command output, the consistency and reproducibility of parameter settings are ensured, and a clear visual basis and adjustment foundation are provided for subsequent manual review.

[0067] This system offers multiple trigger condition confirmation paths during initial startup, balancing efficiency, security, and individual adaptability: the algorithm automatically locks onto the target frequency band and configures phase trigger conditions, quickly completing initial parameter settings and reducing manual operation and startup waiting time; a visual interface displays the frequency domain signal, lockable frequency bands, and configurable phase trigger conditions, relying on manual review and confirmation to fully leverage the professional judgment of clinicians, ensuring that parameter selection aligns with the patient's actual pathological characteristics and enhancing security; furthermore, a manual correction mechanism is introduced based on algorithmic locking, allowing doctors to adjust and reconfirm the automatically generated target frequency band and phase trigger conditions, utilizing the algorithm's objective analytical capabilities to narrow the screening range while retaining space for manual correction and individualized optimization. These three methods complement each other, achieving an organic unity of rapid startup, professional review, and flexible correction during the initial startup phase.

[0068] Example 3 Figure 3 This is a schematic diagram illustrating the implementation process of a pulse stimulation system for an implantable medical device provided in this application. Based on the foregoing embodiments, this embodiment will provide a detailed description of the phase prediction module and the pulse delivery module. Specific implementation methods can be found in the technical solution of this embodiment. Technical terms that are the same as or corresponding to those in the above embodiments will not be repeated here.

[0069] like Figure 3 As shown, the specific steps include the following: S310. Acquire the electrical signal collected by the implantable pulse generator through any one or more electrodes, and perform frequency domain transformation on the electrical signal to obtain a frequency domain signal.

[0070] S320: In response to the confirmation command from the programmable control equipment, lock the target frequency band according to the frequency domain signal, and configure the target phase triggering conditions corresponding to the target frequency band.

[0071] S330: Filter the acquired electrical signal based on the target frequency band to obtain the target oscillation signal.

[0072] The target oscillation signal refers to the pure oscillation signal obtained by filtering the acquired electrical signal based on the target frequency band, which retains only the frequency components within the target frequency band.

[0073] Specifically, in order to obtain a purer signal component that is more focused on the target frequency band, the target frequency band can be used as the basis for frequency screening. The previously acquired raw electrical signal is filtered. The filtering operation attenuates or removes irrelevant frequency components outside the target frequency band, while retaining the signal components within the target frequency band. The signal obtained after this filtering process is the target oscillation signal, which reflects the oscillation rhythm characteristics corresponding to the target frequency band.

[0074] In one specific implementation, bandpass filtering is used for the filtering process. The passband range of the bandpass filter is set to match the previously locked target frequency band. That is, all frequency components between the lower and upper limits of the target frequency band are retained, while signal components below the lower limit and above the upper limit are effectively filtered out. Through this bandpass filtering, irrelevant frequency noise, power frequency interference, and high-frequency spurious components mixed in the original acquired electrical signal are significantly suppressed. The output signal retains only the rhythmic, pure signal closely related to the neural oscillation activity in the target frequency band. This pure signal is the target oscillation signal, which can more realistically reflect the amplitude fluctuations and phase evolution of neural electrophysiological activity within the target frequency band.

[0075] S340. Input the target oscillation signal into the time series prediction model to determine the future time series signal.

[0076] Among them, the time series prediction model refers to the prediction algorithm module used to infer the future trend of signal change based on the historical data of the input target oscillation signal.

[0077] Specifically, the target oscillation signal, as a pure data sequence reflecting the historical changes in neural oscillations within the target frequency band, is fed into a time-series prediction model for processing. The time-series prediction model internally constructs a mapping relationship from historical signal sequences to future signal states. When the target oscillation signal is input into this model, it uses its built-in computational mechanism to deduce the amplitude or state changes of the signal at subsequent times based on the implicit rhythmic patterns, amplitude variation trends, and phase evolution patterns within the target oscillation signal. The result calculated in this way is the future time-series signal, which is a predictive description of the continuous changes of the target oscillation signal on the future time axis.

[0078] In this embodiment, the time series prediction model can be implemented using various different algorithm architectures. As one option, the time series prediction model employs an autoregressive model. This model analyzes the historical numerical sequence of the target oscillation signal, estimates the regression coefficients corresponding to each historical moment, establishes a mathematical correlation between historical signal values ​​and future signal values, and then recursively calculates the predicted signal amplitude for subsequent moments based on the latest historical data. Another option is a state-space model. This model treats the target oscillation signal as an external output driven by internal latent state variables. It recursively estimates the system state and extrapolates the system output for future moments using state transition rules, thereby obtaining the future time series signal. Yet another option is a neural network prediction model. This model, trained on a large number of historical signal samples, autonomously learns the implicit nonlinear time-series dependence features and rhythmic patterns in the signal. When the current target oscillation signal sequence is input, the neural network outputs the predicted result of the future time series signal based on the learned mapping relationship. Regardless of which model is used, the time series prediction model takes the historical data of the target oscillation signal as input and the future time series signal as output. The future time series signal is a predictive description of the continuous amplitude changes of the target oscillation signal on the future time axis.

[0079] S350: Extract the phase of future moments based on future time-series signals and generate a future phase time schedule.

[0080] The future phase refers to the specific instantaneous phase position extracted from the future time series signal, corresponding to the oscillation period of the target oscillation signal at each future time point.

[0081] In this embodiment, the phase prediction information may include a future phase timetable. A future phase timetable is a time-phase lookup table that extracts the instantaneous phase information corresponding to each future time point from the future time-series signal and arranges them in chronological order.

[0082] Specifically, the future time-series signal already provides predicted amplitude or state values ​​of the target oscillation signal at various future time points. To convert these predicted values ​​into phase information that can be used to determine the timing of pulse delivery, the specific instantaneous phase position within the oscillation period of the signal at each future time point can be extracted from the future time-series signal one by one. This extraction process is based on the inherent correspondence between the signal waveform and its phase, thus obtaining the phase value corresponding to each future time point. After completing the phase extraction of all future time points, these time points and their corresponding instantaneous phase information are arranged in chronological order to form a complete time-phase comparison record. This record is the phase prediction information, and the table clearly lists the instantaneous phase of the target oscillation signal corresponding to each future time point.

[0083] In one specific implementation, the Hilbert transform is used to analyze the future time-series signal. Specifically, the Hilbert transform converts the real signal of the future time-series signal into a complex analytic signal. The real part of this complex analytic signal is the original future time-series signal itself, while the imaginary part is the orthogonal component obtained after performing the Hilbert transform on the future time-series signal. Based on this complex analytic signal, the instantaneous phase angle corresponding to each time point is calculated using polar coordinate transformation. This instantaneous phase angle reflects the specific position of the future time-series signal within the oscillation period at each predicted time. Arranging the instantaneous phase angles of each predicted time point in chronological order forms a future phase time table, which comprehensively describes the phase value distribution of the neural oscillation signal at various times over a future period.

[0084] S360. In the phase prediction information, select the time point that meets the target phase triggering condition and form the time point into a stimulus release schedule.

[0085] In this embodiment, the stimulus delivery decision information may include a stimulus delivery schedule. The stimulus delivery schedule is an execution plan that compares phase prediction information with the target phase triggering conditions, selects all specific delivery times that meet the triggering conditions, and arranges them in chronological order.

[0086] Specifically, the phase prediction information details the instantaneous phase information of each future time point and its corresponding target oscillation signal. The target phase triggering conditions have also been configured, specifying the exact phase range within the oscillation period where the pulse should be emitted. To determine the specific pulse emission time, the instantaneous phase corresponding to each time point recorded in the phase prediction information is compared one by one with the target phase triggering conditions. It is determined whether the instantaneous phase falls within the phase range specified by the triggering conditions. Only time points whose instantaneous phases meet the target phase triggering conditions are retained. After filtering all future time points, all selected time points are extracted from the phase prediction information and arranged in chronological order, ultimately forming a time series table that clearly defines the specific times for all pulse emission. This list is the stimulus emission schedule, directly indicating when the pulse emission operation needs to be performed.

[0087] S370. According to the stimulation delivery schedule, control the implantable pulse generator to deliver pulses to any one or more electrodes.

[0088] Specifically, the stimulus delivery schedule lists all pulse delivery times that meet the target phase triggering conditions. These times are arranged chronologically, forming a complete time-series execution plan. Next, based on the time sequence specified in the stimulus delivery schedule, a corresponding pulse trigger control signal is sent to the implanted pulse generator at each designated time. This control signal drives the generator's internal circuitry to produce electrical pulses, which are then output to the target brain tissue via any one electrode or multiple electrodes connected to the lead wire. Throughout this process, the implanted pulse generator strictly adheres to the time nodes in the stimulus delivery schedule, neither too early nor too late, ensuring that each pulse accurately falls at the oscillation phase position required by the target phase triggering conditions, achieving precise temporal intervention in neural activity.

[0089] The technical solution of this application embodiment generates phase prediction information based on future time-series signals. It obtains a target oscillation signal by filtering the acquired electrical signal based on the target frequency band, then inputs this target oscillation signal into a time-series prediction model to determine the future time-series signal. Based on the future time-series signal, it extracts the phase at future moments to generate phase prediction information. This process achieves a complete transformation from historical signals to future phase information, enabling phase prediction to focus on the pure oscillation components of the target frequency band. It effectively suppresses the interference of out-of-band noise and jointless laws on phase estimation. Simultaneously, by leveraging the time-series prediction model's ability to predict signal evolution trends, it obtains instantaneous phase information for each future moment in advance. This provides an accurate and continuous phase data foundation for subsequently selecting release moments that meet the phase triggering conditions, improving the accuracy of phase locking and the responsiveness to signal fluctuations.

[0090] The technical solution of this application embodiment selects the time point that meets the target phase triggering condition from the phase prediction information to form a stimulation delivery schedule, and controls the implantable pulse generator to deliver pulses to any one or more electrodes according to the stimulation delivery schedule. This method makes the determination of the pulse delivery time no longer dependent on real-time phase detection, but based on the timing arrangement of the pre-predicted and screened phase matching time. Thus, phase-locked stimulation can be achieved without continuous acquisition and analysis of electrical signals during the pulse execution phase, which effectively reduces the workload of the signal acquisition module of the implantable pulse generator in closed-loop operation. At the same time, it ensures that the timing of each pulse delivery is pre-matched with the target phase triggering condition, improving the accuracy of the stimulation timing and the execution efficiency.

[0091] Example 4 Figure 4This is a schematic diagram illustrating the implementation process of a pulse stimulation system for an implantable medical device provided in this application. Based on the aforementioned embodiments, this embodiment acquires the actual phase through periodic wake-up and compares it with the predicted phase. While calibrating the deviation, if the error exceeds the standard, a safety mode is switched and an early warning is issued. For specific implementation details, please refer to the technical solution of this embodiment. Technical terms that are the same as or corresponding to those in the above embodiments will not be repeated here.

[0092] like Figure 4 As shown, the specific steps include the following: S410. Acquire the electrical signal collected by the implantable pulse generator through any one or more electrodes, and perform frequency domain transformation on the electrical signal to obtain a frequency domain signal.

[0093] S420: In response to the confirmation command from the programmable control equipment, lock the target frequency band according to the frequency domain signal, and configure the target phase triggering condition corresponding to the target frequency band.

[0094] S430: Predict future timing signals based on electrical signals in the target frequency band, and generate phase prediction information based on the future timing signals.

[0095] S440. Determine stimulus delivery decision information based on phase prediction information and target phase triggering conditions, so that any one or more electrodes can deliver pulses according to the stimulus delivery decision information.

[0096] S450: Wake up the signal acquisition module of the implantable pulse generator according to the preset cycle and turn off the pulse delivery module, and acquire the current electrical signal through any one or more electrodes.

[0097] The preset cycle refers to the pre-defined time interval length used for intermittently waking the signal acquisition module. Different preset cycles are set for different time periods. Specifically, based on the differences in the physiological rhythms or changes in regulatory needs of the target subject at different times, a day or a continuous operating period can be divided into multiple time periods. A corresponding preset cycle length is configured for each time period. This allows for a longer preset cycle during periods of relatively stable neural oscillation rhythms to reduce the frequency of wake-up acquisition, while a shorter preset cycle is used during periods where rhythms are prone to drift or therapeutic effects fluctuate significantly to increase calibration density. This optimizes the match between the timing of the signal acquisition module's wake-up and actual clinical changes. For example, during periods of high patient activity during the day, the preset cycle is set to once every hour for intensive calibration to address signal fluctuations; while during the patient's resting and sleeping period at night, the preset cycle is extended to once every 3 hours to reduce power consumption and adapt to relatively stable physiological rhythms.

[0098] Compared to the fixed and frequent minute-level (e.g., 3-minute, 5-minute) acquisition cycles in existing technologies, this embodiment flexibly adjusts the wake-up interval according to the patient's day and night activity levels. Specifically, a denser cycle is used during periods of high daytime activity to ensure tracking accuracy, while the cycle is appropriately extended during periods of rest at night to reduce the acquisition frequency. While ensuring stimulation accuracy and clinical safety, this dynamic adjustment mechanism significantly reduces the overall number of acquisitions, thereby significantly reducing system power consumption, effectively extending the battery life of the implantable device, and overcoming the drawback of excessive power consumption in traditional fixed high-frequency acquisition modes.

[0099] The signal acquisition module refers to the front-end signal pickup circuit within the implanted pulse generator, responsible for acquiring electrical signals. The current electrical signal refers to the real-time electrical signal acquired at the current moment through any one or more electrodes after the signal acquisition module is activated according to a preset cycle.

[0100] Specifically, during the continuous operation of closed-loop neuromodulation, in order to maintain prediction accuracy and prevent error accumulation due to physiological rhythm drift, calibration operations need to be performed periodically according to a pre-set cycle. At the end of each pre-set cycle, the signal acquisition module, the front-end circuit responsible for signal pickup within the implantable pulse generator, is awakened from its dormant or low-power state, restoring it to normal operating status and enabling it to acquire electrical signals. Simultaneously with waking the signal acquisition module, the pulse delivery module is deactivated. After the signal acquisition module is awakened, the implantable pulse generator immediately picks up real-time electrical signals from the target subject's brain tissue through any one electrode or multiple electrodes connected to it at the end of the electrode wire. This electrical signal acquired at the moment of awakening is the current electrical signal, reflecting the true state of neural oscillation in the target frequency band at the current moment.

[0101] S460. Based on the current electrical signal, determine the current actual phase characteristics; based on the current actual phase characteristics and the phase at the corresponding time in the phase prediction information, determine the phase error.

[0102] Among them, the current actual phase characteristics refer to the phase information extracted from the current electrical signal that reflects the instantaneous phase position of the target frequency band oscillation signal.

[0103] The phase error refers to the difference between the current actual phase characteristics and the predicted phase at the same moment in the phase prediction information.

[0104] Specifically, phase information reflecting the instantaneous phase position of the target frequency band oscillation signal can be extracted from the current electrical signal. This extracted phase information is the current actual phase characteristic. Simultaneously, the phase prediction information already records the predicted phase information for each future time point from the current moment. Therefore, the current actual phase characteristic can be compared with the predicted phase at the corresponding time point in the phase prediction information. That is, the difference between the actually measured phase and the pre-predicted phase can be compared, and the result of subtracting the two or calculating the deviation is the phase error. The magnitude of this phase error directly reflects the degree of deviation of the predicted phase from the true phase at the current moment.

[0105] S470. When the phase error is less than or equal to the preset tolerance threshold, refresh the stimulus delivery decision information based on the current electrical signal, shut down the signal acquisition module and turn on the pulse delivery module.

[0106] The preset tolerance threshold refers to the upper limit of the phase error that is set in advance, which is used to determine whether the prediction deviation is within an acceptable range.

[0107] Among them, the preset periodic wake-up strategy refers to a closed-loop calibration mechanism that periodically wakes up the signal acquisition module according to a preset period to acquire the current electrical signal and evaluate the prediction accuracy.

[0108] Specifically, after calculating the phase error, it can be compared with a pre-set tolerance threshold, which defines the upper limit of the allowable prediction deviation. When the phase error is less than or equal to the preset tolerance threshold, it indicates that the deviation between the predicted phase and the actual phase at the current moment is still within an acceptable accuracy range, meaning the prediction model's output still has sufficient reliability. In this case, it is not necessary to pause the current control strategy or switch to other operating modes, but the future prediction benchmark still needs to be updated to eliminate accumulated minor deviations. Based on this judgment, the real-time phase information contained in the current electrical signal is used as a new reference benchmark to update and correct the original phase prediction information. This involves recalculating the predicted phase for subsequent moments based on the actual phase state at the current moment, replacing the original phase prediction information with the updated phase information, and re-selecting moments that meet the conditions based on the updated phase prediction information and the target phase triggering conditions, forming a new stimulus delivery decision information. At this point, the signal acquisition module can be turned off and the pulse delivery module turned on. Thus, the prediction benchmark is corrected in a timely manner by refreshing the stimulus delivery decision information before the prediction deviation exceeds the tolerance range, maintaining the accuracy of the subsequent pulse delivery timing.

[0109] S480. When the phase error exceeds the preset tolerance threshold, exit the preset cycle wake-up strategy, control the implanted pulse generator to switch to the safety bottom line mode, and send a warning signal to the programmable device.

[0110] The safety baseline mode refers to a conservative stimulation operation state that automatically switches to when the phase error exceeds a preset tolerance threshold, ensuring the safety of the modulation. In the safety baseline mode, the implantable pulse generator controls one or more electrodes to deliver preset pulses, entering an open-loop stimulation mode. The open-loop stimulation mode means that during operation, the implantable pulse generator no longer dynamically adjusts the pulse delivery parameters or timing based on real-time acquired electrical signals or phase prediction information. Instead, it controls one or more electrodes to continuously deliver preset pulses according to pre-set fixed pulse parameters.

[0111] For example, when the phase error exceeds the preset tolerance threshold, the implantable pulse generator automatically switches to the safety bottom line mode, and continuously outputs low-frequency pulses to the target brain tissue through electrode contacts according to the preset low-frequency fixed frequency (range 0-150Hz, typical values ​​such as 80Hz, 100Hz, 120Hz) until the doctor intervenes to recalibrate through the programmable device or manually exits the mode.

[0112] Among them, the warning signal refers to the warning notification information sent by the implanted pulse generator to the programmable control equipment when the phase error exceeds the preset tolerance threshold.

[0113] Specifically, if the phase error exceeds the preset tolerance threshold, it indicates that the deviation between the predicted phase and the actual phase at the current moment has exceeded the pre-set acceptable range. This means that the output of the prediction model is no longer reliable, and continuing to deliver pulses based on the original prediction timing may lead to a serious deviation of the stimulation timing from the target phase, or even adverse modulation effects. In this situation, it is necessary to immediately terminate the existing routine maintenance mechanism of periodically waking up the signal acquisition module for calibration according to a preset cycle. That is, exit the preset cycle wake-up strategy and stop performing periodic calibration operations according to the originally set time intervals. Simultaneously, the implantable pulse generator immediately switches from the current closed-loop phase-locked modulation state to the safety baseline mode. In this mode, the implantable pulse generator no longer relies on the predicted phase information but continuously outputs pulses with a fixed rhythm according to pre-set conservative parameters to ensure that basic electrical stimulation protection can still be provided to the target object in the event of prediction failure. Simultaneously with switching to the safety baseline mode, the implantable pulse generator sends a warning signal to the programmable control device. This warning signal carries the status information of the phase error exceeding the limit and the mode switch, used to notify the operator of the current modulation anomaly and prompt for manual intervention for reassessment and parameter configuration.

[0114] To further optimize the dynamic balance between the wake-up frequency and prediction accuracy of the signal acquisition module, and to avoid the problems caused by either excessively dense calibration leading to wasted power or excessively sparse calibration resulting in accumulated deviations, an adaptive period adjustment mechanism based on phase difference accumulation statistics is introduced. Specifically, when the accumulated phase difference is less than or equal to the accumulated threshold within a preset time period, the preset period is increased by a preset step size; when the accumulated phase difference is greater than the accumulated threshold within a preset time period, the preset period is decreased by a preset step size.

[0115] In this embodiment, if the cumulative phase difference is less than or equal to the cumulative threshold within a preset time period, it indicates that the cumulative prediction deviation under the current preset period is at a low level and the prediction accuracy remains good. At this time, the preset period is increased by a preset step size to extend the wake-up interval and reduce the number of wake-ups of the signal acquisition module. Conversely, if the cumulative phase difference is greater than the cumulative threshold within the preset time period, it indicates that the cumulative phase deviation under the current preset period has exceeded the tolerance range, and there is a risk of prediction drift. At this time, the preset period is decreased by a preset step size to shorten the wake-up interval and increase the calibration density. This adaptive adjustment mechanism can automatically extend the calibration interval to save the power consumption of the implanted pulse generator during periods of high prediction accuracy and automatically increase the calibration density to maintain prediction accuracy during periods of rapid prediction deviation accumulation, thereby achieving a dynamic optimization balance between power consumption and control accuracy.

[0116] This system employs a preset periodic wake-up acquisition mechanism while simultaneously shutting down pulse delivery. During non-acquisition periods, it maintains low power consumption. The wake-up cycle is flexibly adjusted based on different time periods, such as daytime activity and nighttime rest, enabling on-demand acquisition and further optimizing energy allocation. After each wake-up, the system assesses stimulation accuracy in real-time based on the deviation between the current actual phase and the predicted phase. When the error is within tolerable limits, the system promptly updates stimulation decision information to maintain the precision of closed-loop control and therapeutic effect. When the cumulative error is small, the wake-up interval is automatically increased; conversely, it is shortened, thus achieving a dynamic balance between energy saving and accuracy while ensuring effective tracking. If the error exceeds the limit, the system immediately exits the periodic wake-up strategy, switches to an open-loop stimulation safety baseline mode, and sends an alert to the programmable device. This ensures that basic treatment can be maintained even in abnormal situations and alerts the doctor for timely intervention, effectively protecting patient safety. The synergistic effect of these mechanisms achieves a balance between low power consumption, high accuracy, and high safety.

[0117] In the long-term operation of closed-loop neural modulation, the phase prediction based on the prediction model will inevitably produce prediction deviations due to the natural drift of the organism's physiological rhythms, changes in tissue response, or external environmental interference. If not calibrated, these deviations will accumulate over time, causing the pulse delivery timing to gradually deviate from the target phase, ultimately weakening the modulation effect or even causing adverse stimulation. To effectively address this problem, a dynamic correction mechanism based on periodic calibration and error judgment is introduced. Specifically, it includes: waking up the signal acquisition module of the implanted pulse generator and turning off the pulse delivery module according to a preset period, and acquiring the current electrical signal through any one or more electrodes; determining the current actual phase characteristics based on the current electrical signal; determining the phase error based on the current actual phase characteristics and the phase at the corresponding time in the phase prediction information; when the phase error is less than or equal to a preset tolerance threshold, refreshing the stimulation delivery decision information based on the current electrical signal, turning off the signal acquisition module and turning on the pulse delivery module; when the phase error is greater than the preset tolerance threshold, exiting the preset periodic wake-up strategy, controlling the implanted pulse generator to switch to the safety bottom line mode, and sending a warning signal to the programmable device. By comparing the actual phase with the predicted phase in the above periodic sampling, the system can promptly refresh the stimulus delivery decision information with the current electrical signal to correct the accumulated deviation when the prediction accuracy remains effective. At the same time, it can decisively switch to the safety bottom line mode and issue an early warning when the prediction is seriously inaccurate. Thus, it can achieve active monitoring and real-time intervention of prediction drift while ensuring the safety of regulation, taking into account both the long-term stable operation of the closed-loop system and the risk control under abnormal conditions.

[0118] Example 5 Figure 5 This is a schematic flowchart of a pulse stimulation method for an implantable medical device provided in an embodiment of this application. This embodiment is applicable to various situations that require closed-loop neural modulation of neurophysiological signals in the brain. The method can be executed by a phase prediction-based neural modulation device, which can be implemented in the form of software and / or hardware. The hardware can be a controller, such as a mobile terminal, a PC, or a server.

[0119] like Figure 5 As shown, the pulse stimulation method for implantable medical devices provided in this embodiment of the invention includes the following steps: S510: The signal acquisition and processing module acquires the electrical signals collected by the implanted pulse generator through any one or more electrodes, and performs frequency domain transformation on the electrical signals to obtain frequency domain signals.

[0120] Specifically, before or during closed-loop neuromodulation of the target subject, an implantable pulse generator, through electrodes connected to and deployed at specific target points in the target subject's brain, passively senses or actively acquires raw signals of local field potentials. These electrical signals reflect the synchronized electrical activity and rhythmic oscillations of the neuronal population surrounding the electrodes. To extract frequency features usable for modulation decisions from these electrical signals, a frequency domain transformation operation can be performed on the acquired signals. This transforms the signals from a time-domain representation that varies with time to a frequency-domain representation that is distributed according to frequency. The resulting frequency domain signal clearly shows the energy distribution of the electrical signal at different frequency positions, allowing for the identification of specific oscillation frequency bands with significant physiological or pathological relevance. This provides quantitative spectral basis for locking the target frequency band and configuring corresponding phase triggering conditions.

[0121] S520: The trigger condition determination module responds to the confirmation command of the programmable control equipment, locks the target frequency band according to the frequency domain signal, and configures the target phase trigger condition corresponding to the target frequency band.

[0122] Specifically, after the programmable device completes spectrum analysis and displays relevant spectrum information, the operator can issue a confirmation command based on clinical judgment. Receiving this confirmation command triggers the subsequent parameter locking and configuration process. Specifically, a specific frequency range associated with pathological neural oscillations can be determined from the spectrum distribution displayed by the frequency domain signal; this range is locked as the target frequency band. This locking action references both objective data from the frequency domain signal and incorporates the human selection intent carried by the confirmation command. Based on the clearly defined target frequency band, further phase correlation criteria are set for the oscillation waveform characteristics corresponding to this target frequency band, i.e., configuring the target phase trigger condition corresponding to the target frequency band. This trigger condition specifies the phase position of the stimulation pulse in the oscillation cycle at which it should be output, thereby ensuring that the subsequently emitted pulses can accurately match the rhythmic characteristics of the target frequency band in timing.

[0123] S530: The phase prediction module predicts future timing signals based on electrical signals in the target frequency band, and generates phase prediction information based on the future timing signals.

[0124] Specifically, after identifying the target frequency band and obtaining the corresponding electrical signal, these signals can be used to deduce the subsequent signal evolution that has not yet occurred. The specific method involves using a built-in predictive computing mechanism, based on the historical variation patterns of the electrical signal in the target frequency band, to calculate how the signal will continue to fluctuate over time in the future. The resulting prediction is the future time-series signal.

[0125] After obtaining the future time-series signal, it is necessary to analyze the specific phase position within the oscillation period of the signal at each future time point. This phase information is then arranged in a one-to-one correspondence with the corresponding time points, forming a phase comparison record organized chronologically. This record is the phase prediction information. Through this process, the abstract future time-series signal is transformed into a directly queryable correspondence between phase and time, providing clear time coordinates for subsequently determining when the phase conditions for pulse emission are met.

[0126] S540: The pulse delivery module determines the stimulus delivery decision information based on the phase prediction information and the target phase triggering conditions, so that any one or more electrodes can deliver pulses according to the stimulus delivery decision information.

[0127] Specifically, the phase prediction information provides the instantaneous phase information of the target frequency band oscillation signal corresponding to each future moment. Simultaneously, the target phase triggering conditions have already been configured, specifying the exact phase positions of the pulse output within the oscillation cycle. Therefore, each future moment listed in the phase prediction information and its corresponding phase information needs to be compared and judged against the pre-set target phase triggering conditions. Only when the phase information of a future moment falls within or matches the phase range required by the triggering condition is that moment considered to meet the timing requirements for pulse delivery. All these future moments that meet the conditions are selected and arranged chronologically to form a timing execution plan that clearly defines the specific moments for each pulse delivery; this plan is the stimulus delivery decision information. After the stimulus delivery decision information is determined, the implanted pulse generator outputs electrical pulses through any one or more electrodes at each specified moment according to the time sequence specified in the stimulus delivery decision information, thereby ensuring that the pulse delivery timing is precisely locked at the target phase position of the target frequency band oscillation cycle.

[0128] In this embodiment, when the pulse emission module emits a pulse, the signal acquisition module is in a non-acquisition state. This can be understood as actively shutting down the signal acquisition paths of all electrode channels within the brief time window of the pulse output, stopping the sampling, amplification, and buffering of the electrical signal. This is done to prevent the high-intensity electric field generated during pulse release from causing electrical saturation interference or residual artifacts to the front-end acquisition circuit, thereby protecting the acquisition device and avoiding contamination of the original signal. This ensures that the electrical signal acquired by the signal acquisition and processing module is pure and interference-free, allowing subsequent frequency domain transformation, target frequency band locking, and phase prediction to be based on real physiological rhythms, avoiding misjudgments of trigger conditions due to pulse artifacts. Simultaneously, the timing separation of acquisition and emission eliminates clock conflicts, ensuring the continuity of phase prediction information and the accuracy of pulse emission decisions, ultimately improving the overall anti-interference capability and long-term operational stability of the system.

[0129] This application provides a pulse stimulation method for an implantable medical device. A signal acquisition and processing module acquires electrical signals collected by an implantable pulse generator through one or more electrodes, and performs frequency domain transformation on the electrical signals to obtain frequency domain signals. A trigger condition determination module responds to confirmation commands from a programmable control device, locks onto a target frequency band based on the frequency domain signals, and configures target phase trigger conditions corresponding to the target frequency band. A phase prediction module predicts future timing signals based on the electrical signals of the target frequency band and generates phase prediction information based on the future timing signals. A pulse delivery module determines stimulation delivery decision information based on the phase prediction information and the target phase trigger conditions, so that one or more electrodes deliver pulses according to the stimulation delivery decision information. When the pulse delivery module delivers pulses, the signal acquisition module is in a non-acquisition state. This technical solution, by acquiring electrical signals and locking onto a target frequency band, combining manual confirmation and configuration of phase trigger conditions, and then determining the pulse delivery timing based on the predicted phase prediction information, achieves prediction-based phase-locked stimulation. This solves the problems of existing solutions being unable to accurately intervene at a single waveform scale, excessive energy consumption due to continuous real-time tracking, and signal interference causing trigger timing deviations. It improves stimulation accuracy and reduces operational burden.

[0130] Based on the above embodiments, the method further includes: waking up the signal acquisition module of the implantable pulse generator and shutting down the pulse delivery module according to a preset cycle, and acquiring the current electrical signal through any one or more electrodes; wherein, the preset cycle is set with different cycles for different time periods; determining the current actual phase characteristics based on the current electrical signal; determining the phase error based on the current actual phase characteristics and the phase at the corresponding time in the phase prediction information; when the phase error is less than or equal to a preset tolerance threshold, refreshing the stimulus delivery decision information based on the current electrical signal, shutting down the signal acquisition module and turning on the pulse delivery module; when the phase error is greater than the preset tolerance threshold, exiting the preset cycle wake-up strategy, controlling the implantable pulse generator to switch to the safety bottom line mode, and sending a warning signal to the programmable control device.

[0131] Example 6 Figure 6 This is a schematic diagram of the structure of an implantable medical device provided in an embodiment of this application. The implantable medical device 50 includes at least an electrode lead 510 implanted in the brain of a target subject and a pulse generator 520 implanted in the body of the target subject. The implanted end of the electrode lead 510 is provided with at least one or more electrodes, and the pulse generator 520 is connected to the electrode lead 510. The pulse generator 520 includes: The signal acquisition and processing unit 5201 is used to acquire electrical signals acquired through any one or more electrodes and perform frequency domain transformation on the electrical signals to obtain frequency domain signals. Communication unit 5202 is used to receive confirmation commands from programmable control equipment; The parameter configuration unit 5203 is used to lock the target frequency band according to the frequency domain signal in response to the confirmation command, and configure the target phase triggering conditions corresponding to the target frequency band; The phase prediction unit 5204 is used to predict future timing signals based on electrical signals in the target frequency band, and to generate phase prediction information based on the future timing signals. The pulse control unit 5205 is used to determine stimulus delivery decision information based on phase prediction information and target phase triggering conditions, and to control any one or more electrodes to deliver pulses based on the stimulus delivery decision information; wherein, when the pulse delivery module delivers pulses, the signal acquisition module is in a non-acquisition state.

[0132] The technical solution of this application embodiment includes an implantable medical device. The pulse generator acquires electrical signals collected by the implantable pulse generator through any one or more electrodes, and performs frequency domain transformation on the electrical signals to obtain frequency domain signals. In response to a confirmation command from a programmable control device, it locks a target frequency band based on the frequency domain signals and configures target phase triggering conditions corresponding to the target frequency band. Based on the electrical signals of the target frequency band, it predicts future timing signals and generates phase prediction information based on the future timing signals. Based on the phase prediction information and the target phase triggering conditions, it determines stimulus delivery decision information so that any one or more electrodes deliver pulses according to the stimulus delivery decision information. When the pulse delivery module delivers pulses, the signal acquisition module is in a non-acquisition state. The technical solution of this application accurately locks the target frequency band through frequency domain transformation and, combined with manual confirmation of the phase triggering conditions, lays the foundation for precise stimulation. It utilizes a predictive model to extrapolate the future timing of the target frequency band signal, predicting the optimal stimulation phase in advance, effectively overcoming system transmission and processing delays, and ensuring that the pulse is accurately anchored to the predetermined phase window, thereby significantly improving treatment consistency. Simultaneously, the system actively pauses acquisition during pulse delivery to avoid ineffective power consumption, further extending the device's battery life while ensuring tracking effectiveness. This achieves a synergistic optimization of high precision and low energy consumption, solving the problem of existing solutions being unable to accurately intervene at the single waveform scale and causing excessive energy consumption due to continuous real-time tracking. This improves stimulation accuracy and reduces the system's operational burden.

[0133] Example 7 This application also provides a storage medium containing computer-executable instructions, which, when executed by a computer processor, are used to perform a pulse stimulation method for an implantable medical device, the method comprising: Acquire electrical signals collected by an implantable pulse generator through any one or more electrodes, and perform frequency domain transformation on the electrical signals to obtain frequency domain signals; In response to the confirmation command from the programmable control equipment, the target frequency band is locked according to the frequency domain signal, and the target phase triggering condition corresponding to the target frequency band is configured; Predict future timing signals based on the electrical signals in the target frequency band, and generate phase prediction information based on the future timing signals; Stimulus firing decision information is determined based on phase prediction information and the target phase triggering condition, so that any one or more electrodes fire pulses according to the stimulus firing decision information; wherein, when the pulse firing module fires a pulse, the signal acquisition module is in a non-acquisition state.

[0134] The computer storage medium in this application embodiment can be any combination of one or more computer-readable media. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0135] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0136] Program code contained on a computer-readable medium may be transmitted using any suitable medium, including—but not limited to—wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0137] Computer program code for performing the operations of the embodiments of this application can be written in one or more programming languages ​​or a combination thereof. Programming languages ​​include object-oriented programming languages—such as Java, Smalltalk, and C++—and conventional procedural programming languages—such as C or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0138] Note that the above description is merely a preferred embodiment and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of this application, and the scope of this application is determined by the scope of the appended claims.

Claims

1. A pulse stimulation system for an implantable medical device, characterized in that, The system includes: The signal acquisition and processing module is used to acquire electrical signals collected by the implantable pulse generator through any one or more electrodes, and to perform frequency domain transformation on the electrical signals to obtain frequency domain signals. The trigger condition determination module is used to respond to the confirmation command of the programmable device, lock the target frequency band according to the frequency domain signal, and configure the target phase trigger condition corresponding to the target frequency band; A phase prediction module is used to predict future timing signals based on the electrical signals in the target frequency band, and to generate phase prediction information based on the future timing signals. The pulse delivery module is used to determine stimulus delivery decision information based on phase prediction information and the target phase triggering condition, so that any one or more electrodes deliver pulses according to the stimulus delivery decision information; wherein, when the pulse delivery module delivers pulses, the signal acquisition module is in a non-acquisition state.

2. The system according to claim 1, characterized in that, The trigger condition determination module is specifically used for: The programmable device identifies the characteristic frequencies in the frequency domain signal according to the built-in algorithm, locks the target frequency band, configures the target phase triggering conditions corresponding to the target frequency band, and generates a confirmation command.

3. The system according to claim 1, characterized in that, The trigger condition determination module is also specifically used for: The frequency domain signal and the target frequency band that can be locked are displayed through the visual interface of the programmable equipment for review and confirmation. The visual interface of the programmable equipment displays configurable phase triggering conditions for review and confirmation. In response to the manual review and confirmation operation of the programmable device, a confirmation command is generated.

4. The system according to claim 3, characterized in that, The trigger condition determination module is further used for: After the programmable device locks the target frequency band and configures the target phase triggering conditions according to the built-in algorithm, the target frequency band and the target phase triggering conditions are displayed through the visual interface of the programmable device. In response to the manual review and confirmation operation of the programmable device, the target frequency band and / or the target phase triggering conditions are modified to generate a confirmation command based on the modification result.

5. The system according to claim 1, characterized in that, The phase prediction information includes a future phase timetable, and the phase prediction module is specifically used for: The collected electrical signal is filtered based on the target frequency band to obtain the target oscillation signal; The target oscillation signal is input into the time series prediction model to determine the future time series signal; Based on the future time-series signal, the phase of future moments is extracted to generate a future phase time schedule.

6. The system according to claim 1, characterized in that, The pulse delivery module is specifically used for: In the phase prediction information, select the time points that meet the target phase triggering conditions, and form the stimulus release schedule from the time points; According to the stimulation delivery schedule, the implantable pulse generator is controlled to deliver pulses to any one or more electrodes.

7. The system according to claim 1, characterized in that, The system is also used for: The signal acquisition module of the implantable pulse generator is woken up and the pulse delivery module is turned off according to a preset cycle, and the current electrical signal is acquired through any one or more electrodes; Based on the current electrical signal, determine the current actual phase characteristics; Based on the current actual phase characteristics and the phase at the corresponding time in the phase prediction information, the phase error is determined; When the phase error is less than or equal to a preset tolerance threshold, the stimulus delivery decision information is refreshed based on the current electrical signal, the signal acquisition module is turned off and the pulse delivery module is turned on. When the phase error exceeds the preset tolerance threshold, the preset periodic wake-up strategy is exited, the implanted pulse generator is switched to the safety bottom line mode, and a warning signal is sent to the programmable device.

8. The system according to claim 7, characterized in that, The preset period is set to different periods for different time periods.

9. The system according to claim 7, characterized in that, If the cumulative phase difference is less than or equal to the cumulative threshold within a preset time period, the preset period increases by a preset step size; if the cumulative phase difference is greater than the cumulative threshold within the preset time period, the preset period decreases by a preset step size.

10. The system according to claim 7, characterized in that, The safety baseline mode is that the implantable pulse generator controls any one or more electrodes to deliver preset pulses, entering the open-loop stimulation mode.

11. A pulse stimulation method for an implantable medical device, characterized in that, The method includes: The signal acquisition and processing module acquires the electrical signals collected by the implantable pulse generator through any one or more electrodes, and performs frequency domain transformation on the electrical signals to obtain frequency domain signals. In response to the confirmation command from the programmable control device, the trigger condition determination module locks the target frequency band based on the frequency domain signal and configures the target phase trigger condition corresponding to the target frequency band. The phase prediction module predicts future timing signals based on the electrical signals in the target frequency band, and generates phase prediction information based on the future timing signals. The pulse delivery module determines the stimulus delivery decision information based on the phase prediction information and the target phase triggering condition, so that any one or more electrodes deliver pulses according to the stimulus delivery decision information; wherein, when the pulse delivery module delivers pulses, the signal acquisition module is in a non-acquisition state.

12. The method according to claim 11, characterized in that, The method further includes: The implantable pulse generator's signal acquisition module is activated and the pulse delivery module is deactivated according to a preset cycle, and the current electrical signal is acquired through any one or more electrodes; wherein, the preset cycle is set to different cycles in different time periods; Based on the current electrical signal, determine the current actual phase characteristics; Based on the current actual phase characteristics and the phase at the corresponding time in the phase prediction information, the phase error is determined; When the phase error is less than or equal to a preset tolerance threshold, the stimulus delivery decision information is refreshed based on the current electrical signal, the signal acquisition module is turned off and the pulse delivery module is turned on. When the phase error exceeds the preset tolerance threshold, the preset periodic wake-up strategy is exited, the implanted pulse generator is switched to the safety bottom line mode, and a warning signal is sent to the programmable device.

13. An implantable medical device, characterized in that, The implantable medical device includes at least a pulse generator implanted in the body of the target subject and an electrode wire implanted in the brain of the target subject. The implanted end of the electrode wire is provided with at least one or more electrodes, and the pulse generator is connected to the electrode wire. The pulse generator includes: The signal acquisition and processing unit is used to acquire electrical signals acquired through any one or more electrodes, and to perform frequency domain transformation on the electrical signals to obtain frequency domain signals. The communication unit is used to receive confirmation commands from the programmable control equipment. A parameter configuration unit is used to respond to the confirmation command, lock the target frequency band according to the frequency domain signal, and configure the target phase triggering conditions corresponding to the target frequency band; A phase prediction unit is used to predict future timing signals based on the electrical signals in the target frequency band, and to generate phase prediction information based on the future timing signals. A pulse control unit is used to determine stimulus delivery decision information based on phase prediction information and the target phase triggering condition, so that any one or more electrodes deliver pulses according to the stimulus delivery decision information; wherein, when the pulse delivery module delivers pulses, the signal acquisition module is in a non-acquisition state.

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