Signal collection circuit, contact combination method, stimulator, and implantable medical system and device

Abstract

A signal collection circuit, a contact combination method, a stimulator, and an implantable medical system and device. The signal collection circuit comprises a multi-contact electrode, an analog switch, a sampling capacitor array, a multiplexer and a signal sampling module, wherein at least some contacts in the multi-contact electrode extend into a target nucleus; all the contacts in the multi-contact electrode are electrically connected to all sampling capacitors in the sampling capacitor array on a one-to-one basis by means of the analog switch; each sampling capacitor in the sampling capacitor array is electrically connected to the multiplexer, so that the multiplexer performs gating on any two sampling capacitors; and the multiplexer is electrically connected to the signal sampling module.

Description

Signal acquisition circuit, contact combination method, stimulator, implantable medical system and equipment

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on January 19, 2024, with application number 202410077315.X. The entire contents of this application are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of medical device technology, for example, to a signal acquisition circuit, a contact combination method, a stimulator, an implantable medical system and equipment. Background Art

[0003] A stimulator is a type of implantable device, which includes an implantable pulse generator (IPG) and electrode wires. It can provide patients with parameter-controlled, refined electrical stimulation therapy and is recognized by many Parkinson's disease patients in the market.

[0004] To achieve real-time closed-loop stimulation, in addition to electrical stimulation, the electrode contacts must also acquire local field potential (LFP) signals from the subthalamic nucleus (STN). For multi-contact electrodes (N ≥ 2 contacts), the placement of the electrodes in the STN is uncertain due to individual patient variability and surgeon-surgeon variability. This makes it difficult to determine which two contacts (differentially selected to reduce common-mode noise) are optimal for LFP acquisition. Therefore, prior to closed-loop control, multiple contact combinations must be sampled in a round-robin fashion. The optimal acquisition contact combination is determined based on a combination of LFP signal amplitude and signal-to-noise ratio. Two current approaches exist for achieving this: Method 1 adds a signal processing circuit to each electrode contact combination; Method 2 uses two multiplexers to select any two electrode contacts, with the processing circuitry then shared. Method 1 ensures that all electrode contact combinations are sampled simultaneously, ensuring accurate determination of the optimal contact combination. However, the N*(N-1) / 2 signal processing circuits clearly do not meet the IPG design requirements of small size, low weight, and low power consumption. Method 2 reduces the IPG circuit size, but each contact combination actually analyzes LFP data at a different moment (due to shared processing circuitry, round-robin sampling and analysis is required), making it difficult to guarantee accurate determination of the optimal contact combination. Summary of the Invention

[0005] The present application provides a signal acquisition circuit, a contact combination method, a stimulator, an implantable medical system and equipment.

[0006] The present application provides a signal acquisition circuit, comprising a multi-contact electrode, an analog switch, a sampling capacitor array, a multiplexer, and a signal sampling module;

[0007] At least some of the contacts of the multi-contact electrode extend into the target nucleus;

[0008] All contacts in the multi-contact electrode are electrically connected one-to-one with all sampling capacitors in the sampling capacitor array through the analog switch;

[0009] Each sampling capacitor in the sampling capacitor array is electrically connected to the multiplexer, so that the multiplexer selects any two sampling capacitors;

[0010] The multiplexer is electrically connected to the signal sampling module.

[0011] In one or more embodiments, the multiplexer includes a first multiplexer and a second multiplexer;

[0012] Each sampling capacitor in the sampling capacitor array is electrically connected to the first multiplexer and the second multiplexer respectively, and the output end of the first multiplexer and the output end of the second multiplexer are both connected to the signal sampling module.

[0013] In one or more embodiments, the signal sampling module includes a first voltage follower, a second voltage follower, a prefilter, a differential amplifier, a low-pass filter, a programmable amplifier, and an analog-to-digital converter;

[0014] The first multiplexer is electrically connected to the first voltage follower;

[0015] The second multiplexer is electrically connected to the second voltage follower;

[0016] The first voltage follower and the second voltage follower are electrically connected to the pre-filter respectively;

[0017] The pre-filter is electrically connected to the differential amplifier;

[0018] The differential amplifier is electrically connected to the low-pass filter;

[0019] The low-pass filter is electrically connected to the programmable amplifier;

[0020] The programmable amplifier is electrically connected to the analog-to-digital converter.

[0021] In one or more embodiments, the multi-contact electrode includes N contacts, the analog switch includes N channels, the sampling capacitor array includes N sampling capacitors, and the first multiplexer and the second multiplexer are both N-to-1 multiplexers;

[0022] One end of the M-th sampling capacitor is electrically connected to the ground, and the other end thereof is electrically connected to the M-th input end of the first multiplexer and the M-th input end of the second multiplexer, and is electrically connected to the M-th contact of the multi-contact electrode through the M-th channel of the analog switch;

[0023] Wherein, M and N are both integers, N≥2, N≥M≥1.

[0024] In one or more embodiments, the pre-filter includes a DC blocking capacitor unit and an RC low-pass filter unit;

[0025] The first voltage follower and the second voltage follower are electrically connected to the DC blocking capacitor unit respectively;

[0026] The DC blocking capacitor unit is electrically connected to the RC low-pass filter unit;

[0027] The RC low-pass filter unit is electrically connected to the differential amplifier.

[0028] In one or more embodiments, the differential amplifier is a fully differential chopper amplifier.

[0029] In one or more embodiments, the low-pass filter is a seventh-order Chebyshev filter.

[0030] In one or more embodiments, the analog-to-digital converter is a Σ-Δ ADC.

[0031] In one or more embodiments, a single chip microcomputer is further included;

[0032] The single chip microcomputer is electrically connected to the signal sampling module.

[0033] The signal sampling module is configured to acquire an electrical signal between any two contact electrodes according to the multiplexer;

[0034] The single chip microcomputer is configured to perform fast Fourier transform on the electrical signal collected by the signal sampling module to obtain corresponding multiple LFP amplitude-frequency curves, and select the optimal collection contact combination based on the principle of giving priority to the highest LFP signal β frequency band amplitude A and secondly the lowest background noise.

[0035] The present application also provides a contact combination method, which is applied to the above-mentioned signal acquisition circuit, including:

[0036] closing all channels of the analog switch to charge the sampling capacitor array through the multi-contact electrodes;

[0037] After a preset time, all channels of the analog switch are disconnected, and the multiplexer is controlled in a round-robin manner to select any two sampling capacitors, so as to obtain sampling data between any two sampling capacitors in the sampling capacitor array through sampling by the signal sampling module;

[0038] Performing fast Fourier transform on the sampled data between any two sampling capacitors to obtain a set of LFP amplitude-frequency curves;

[0039] Selecting an element from the LFP amplitude-frequency curve set based on the principle that the LFP signal β frequency band amplitude is the highest and the background noise is the lowest, to obtain the optimal LFP amplitude-frequency curve;

[0040] According to the optimal LFP amplitude-frequency curve, an optimal acquisition contact point combination is obtained.

[0041] In one or more embodiments, the priority of the LFP signal with the highest amplitude in the β frequency band is higher than the priority of the background noise with the lowest amplitude.

[0042] In one or more embodiments, the LFP signal β frequency band is 13 to 35 Hz.

[0043] The present application also provides a stimulator, comprising an implantable pulse generator, electrode wires, and the above-mentioned signal acquisition circuit;

[0044] The implantable pulse generator is electrically connected to the multi-contact electrodes in the signal acquisition circuit through the electrode wire.

[0045] The present application also provides an implantable medical system, which is applied to the above-mentioned signal acquisition circuit, comprising:

[0046] a startup module, configured to close all channels of the analog switch to charge the sampling capacitor array through the multi-contact electrode;

[0047] a sampling module configured to disconnect all channels of the analog switch after a preset time has passed, and to control the multiplexer to select any two sampling capacitors in a round-robin manner, so as to obtain sampling data between any two sampling capacitors in the sampling capacitor array through sampling by the signal sampling module;

[0048] A processing module is configured to perform fast Fourier transform on the sampling data between any two sampling capacitors to obtain a set of LFP amplitude-frequency curves;

[0049] A selection module is configured to select an element in the LFP amplitude-frequency curve set according to the principle that the LFP signal β frequency band amplitude is the highest and the background noise is the lowest, so as to obtain an optimal LFP amplitude-frequency curve;

[0050] The output module is configured to obtain an optimal acquisition contact point combination according to the optimal LFP amplitude-frequency curve.

[0051] The present application also provides an implantable medical device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the above-mentioned contact combination method when executing the computer program. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] FIG1 is a structural block diagram of a signal acquisition circuit provided by the present application;

[0053] FIG2 is a structural block diagram of another signal acquisition circuit provided by the present application;

[0054] FIG3 is a schematic diagram of a circuit principle of a signal acquisition circuit provided by the present application;

[0055] FIG4 is a diagram showing the relationship between the frequency and signal amplitude of an LFP signal provided by the present application;

[0056] FIG5 is a schematic diagram of a flow chart of a contact combination method provided by the present application;

[0057] FIG6 is a schematic structural diagram of a stimulator provided by the present application;

[0058] FIG7 is a schematic structural diagram of an implantable medical system provided by the present application;

[0059] FIG8 is a schematic structural diagram of an implantable medical device provided in this application. DETAILED DESCRIPTION

[0060] The present application will be described below in conjunction with the accompanying drawings and embodiments. The embodiments are only used to explain the present application and do not limit the scope of protection of the present application.

[0061] 1 to 4 , the present application provides a signal acquisition circuit, including a multi-contact electrode, an analog switch, a sampling capacitor array, a multiplexer, and a signal sampling module;

[0062] At least some of the contacts of the multi-contact electrode extend into the target nucleus;

[0063] All contacts in the multi-contact electrode are electrically connected one-to-one with all sampling capacitors in the sampling capacitor array through the analog switch;

[0064] Each sampling capacitor in the sampling capacitor array is electrically connected to the multiplexer, so that the multiplexer selects any two sampling capacitors;

[0065] The multiplexer is electrically connected to the signal sampling module.

[0066] In this embodiment, the signal sampling module is configured to acquire the electrical signal between any two contact electrodes based on the multiplexer. Exemplarily, the signal acquisition circuit primarily simultaneously acquires the electrical signal of the nuclei near the contacts via a sampling capacitor array, and performs round-robin acquisition via the multiplexer to determine the optimal acquisition contact combination. The analog switch model may be ADG1414. The multiplexer may be a dual-pass dual-output multiplexer or a combination of two single-pass single-output multiplexers.

[0067] Among them, the multi-contact electrode can be a nerve stimulation electrode, and the electrode wire delivers electrical stimulation to a specific area of ​​tissue in the body through multiple electrode contacts. The stimulator is provided with one or more electrode wires on one side or both sides, and a plurality of electrode contacts are provided on the electrode wire, and the electrode contacts can be arranged uniformly or non-uniformly in the circumference of the electrode wire. As an example, the electrode contacts can be arranged in an array of 4 rows and 3 columns (a total of 12 electrode contacts) in the circumference of the electrode wire. The electrode contacts may include stimulation contacts and / or collection contacts. The electrode contacts can, for example, be in the shape of a sheet, a ring, a point, or the like.

[0068] Among them, at least some of the contacts can be understood as the multi-contact electrode being in use, that is, implanted into a special area of ​​the user's body through surgery or other means, and when working, the special area is stimulated and / or the electrical signal of the special area is collected through the contact, thereby realizing closed-loop control.

[0069] The target nuclei can be special areas of the patient's brain tissue, spinal cord, limbs and other specific tissues, such as the STN, Globus Pallidus internal segment (GPi), ventralis intermedius nucleus (Vim), anterior limb of the internal capsule (AIC) and anterior nucleus of thalamus (ANT).

[0070] In one embodiment, assuming that the multi-contact electrode has N (≥2) contacts, the analog switch is N-way, and the sampling capacitor array includes N sampling capacitors C1 to C NThe multiplexer is composed of one N-to-2 multiplexer or two N-to-1 multiplexers. When determining the optimal acquisition contact combination without applying electrical stimulation, the N channels of the analog switch are closed simultaneously, so that each core coupled to the sampling capacitor provides the sampling capacitors C1 to C2 in the sampling capacitor array. N After sufficient time, the analog switches N-way are disconnected at the same time, and the multiplexer selects C H1 (corresponding to sampling capacitor C1) and C H2 (corresponding to sampling capacitor C2), after being processed by the voltage follower, pre-filter (essentially a band-pass filter), differential amplifier, low-pass filter, and programmable amplifier (PGA) in the signal sampling module, it is sent to the analog-to-digital converter for sampling to obtain a sampled data. H1 (corresponding to sampling capacitor C1), the multiplexer selects C H2 Change to strobe C H3 (corresponding to sampling capacitor C3), and after back-end processing, another sampled data is obtained. The above process is repeated to obtain N*(N-1) / 2 combinations of sampled data. Fast Fourier Transform (FFT) of multiple sampled data sets can be performed to obtain N*(N-1) / 2 LFP amplitude-frequency curves. The optimal acquisition contact combination is selected based on the principle of prioritizing the highest amplitude A (relative to the 150Hz external noise floor baseline) in the LFP signal β frequency band (13-35Hz) and the lowest noise floor.

[0071] This application suppresses common-mode noise through differential LFP sampling to reduce the impact of other physiological signals such as electrooculogram and electrocardiogram on the acquisition of EEG LFP signals; uses simultaneous acquisition of all contacts in a multi-contact electrode to reflect the LFP signals of different positions of the nucleus at the same time, and then finds the optimal acquisition contact combination for EEG LFP signal acquisition through combined pairing analysis, eliminating the uncertainty of the judgment results of the previous time-sharing sampling analysis, and can greatly improve the accuracy of the optimal acquisition contact judgment to achieve the optimal LFP acquisition effect, thereby realizing real-time optimal optimization of electrical stimulation parameters.

[0072] In one or more embodiments, the multiplexer includes a first multiplexer and a second multiplexer;

[0073] Each sampling capacitor in the sampling capacitor array is electrically connected to the first multiplexer and the second multiplexer, respectively. The output of the first multiplexer and the output of the second multiplexer are both connected to the signal sampling module. Considering component cost and assembly space, two multiplexers are provided to quickly connect any two sampling capacitors, thereby obtaining the local field potential between the contacts corresponding to the two sampling capacitors.

[0074] In one or more embodiments, the signal sampling module includes a first voltage follower, a second voltage follower, a prefilter, a differential amplifier, a low-pass filter, a programmable amplifier, and an analog-to-digital converter;

[0075] The first multiplexer is electrically connected to the first voltage follower;

[0076] The second multiplexer is electrically connected to the second voltage follower;

[0077] The first voltage follower and the second voltage follower are electrically connected to the pre-filter respectively;

[0078] The pre-filter is electrically connected to the differential amplifier;

[0079] The differential amplifier is electrically connected to the low-pass filter;

[0080] The low-pass filter is electrically connected to the programmable amplifier;

[0081] The programmable amplifier is electrically connected to the analog-to-digital converter.

[0082] In this embodiment, the first multiplexer and the second multiplexer can each be a single-output multiplexer model ADG5206, and the first voltage follower and the second voltage follower can each be an operational amplifier model AD8622. The positive input of the first voltage follower is electrically connected to the output of the first multiplexer, the positive input of the second voltage follower is electrically connected to the output of the second multiplexer, the negative input of the first voltage follower is electrically connected to the output of the first voltage follower, the negative input of the second voltage follower is electrically connected to the output of the second voltage follower, the output of the first voltage follower is electrically connected to one input of the prefilter, and the output of the second voltage follower is electrically connected to the other input of the prefilter.

[0083] The electrical connection in the present application may be a connection achieved by welding, or a connection achieved by providing a plug-in port.

[0084] In one embodiment, assuming that the multi-contact electrode has N (≥2) contacts, the analog switch is N-way, and the sampling capacitor array includes N sampling capacitors C1 to C N , the first multiplexer and the second multiplexer are both N-select-1 structures. When determining the optimal acquisition contact combination without applying electrical stimulation, first close the N channels of the analog switch at the same time, and respectively supply the multiple sampling capacitors C1 to C N After sufficient time, the N analog switches are disconnected at the same time, and the first multiplexer selects C H1 (corresponding to the sampling capacitor C1), is buffered by the first voltage follower and sent to one end of the pre-filter. The second multiplexer selects C H2 (corresponding to the sampling capacitor C2), is buffered by the second voltage follower and sent to the other end of the pre-filter. The pre-filter (essentially a band-pass filter) filters the signals received at both ends, amplifies them with a differential amplifier, filters them with a low-pass filter, and amplifies them with a programmable amplifier (PGA). The signals are then sent to an analog-to-digital converter such as a Σ-Δ analog-to-digital converter (ADC) for sampling to obtain a sampled data. Keep the first multiplexer selected C H1 (corresponding to sampling capacitor C1), modify the second multiplexer strobe C H3 (corresponding to sampling capacitor C3), and after back-end processing, another sampled data is obtained. The above process is repeated to obtain N*(N-1) / 2 combinations of sampled data. Performing FFT on multiple sets of sampled data can produce N*(N-1) / 2 LFP amplitude-frequency curves. The optimal acquisition contact combination is selected based on the principle of prioritizing the highest amplitude A in the LFP signal's β frequency band (13-35Hz) (relative to the 150Hz external noise floor baseline) and the lowest noise floor.

[0085] In one or more embodiments, the multi-contact electrode includes N contacts, the analog switch includes N channels, the sampling capacitor array includes N sampling capacitors, and the first multiplexer and the second multiplexer are both N-to-1 multiplexers;

[0086] One end of the Mth sampling capacitor is electrically connected to the ground, and the other end thereof is electrically connected to the Mth input end of the first multiplexer and the Mth input end of the second multiplexer, and is electrically connected to the Mth contact of the multi-contact electrode through the Mth channel of the analog switch;

[0087] Wherein, M and N are both integers, N≥2, N≥M≥1.

[0088] In this embodiment, M represents any number between 1 and N. In one embodiment, referring to FIG3 , N is 12, then the multi-contact electrode has 12 contacts, the analog switch is 12-way (which can be composed of two ADG1414 analog switches), and the sampling capacitor array includes 12 sampling capacitors C1 to C 12 , the first multiplexer and the second multiplexer are both 12-choose-1 structures. When determining the optimal acquisition contact combination without applying electrical stimulation, first close the 12 analog switches at the same time, and respectively supply the sampling capacitors C1 to C 12 After sufficient time, the 12 analog switches are disconnected at the same time, and the first multiplexer selects C H1 (corresponding to the sampling capacitor C1), is buffered by the first voltage follower and sent to one end of the pre-filter. The second multiplexer selects C H2 (corresponding to the sampling capacitor C2), is buffered by the second voltage follower and sent to the other end of the pre-filter. The pre-filter (essentially a band-pass filter) filters the signals received at both ends, amplifies them with a differential amplifier, filters them with a low-pass filter, and amplifies them with a programmable amplifier (PGA). The signals are then sent to an analog-to-digital converter such as a Σ-△ ADC for sampling to obtain a sampled data. Keep the first multiplexer selected C H1 (corresponding to sampling capacitor C1), modify the second multiplexer strobe C H3 (corresponding to sampling capacitor C3), and after back-end processing, another sampled data is obtained. The above process is repeated to obtain 66 combinations of sampled data. FFT of multiple sets of sampled data can be performed to obtain 66 LFP amplitude-frequency curves. The optimal acquisition contact combination is selected based on the principle of prioritizing the highest amplitude A in the LFP signal's β frequency band (13-35Hz) (relative to the 150Hz external noise floor baseline) and the lowest noise floor.

[0089] In one or more embodiments, the pre-filter includes a DC blocking capacitor unit and a resistor-capacitor (RC) low-pass filter unit;

[0090] The first voltage follower and the second voltage follower are electrically connected to the DC blocking capacitor unit respectively;

[0091] The DC blocking capacitor unit is electrically connected to the RC low-pass filter unit;

[0092] The RC low-pass filter unit is electrically connected to the differential amplifier.

[0093] In this embodiment, referring to FIG. 3 , the DC blocking capacitor unit may be composed of two 2.2 uF capacitors, and the RC low-pass filter unit may be composed of two 3.3 KΩ resistors and two 100 nF capacitors.

[0094] In one or more embodiments, the differential amplifier is a fully differential chopper amplifier.

[0095] In this embodiment, the fully differential chopper amplifier may be composed of two operational amplifiers of model ADA4528. The signal amplified by the fully differential chopper amplifier may be transmitted to a low-pass filter for further processing.

[0096] In one or more embodiments, the low-pass filter is a seventh-order Chebyshev filter.

[0097] In this embodiment, the seventh-order Chebyshev filter can be composed of an operational amplifier model ADA4528, which can be composed of two groups of three operational amplifiers, for a total of six operational amplifiers. The data filtered by the seventh-order Chebyshev filter can be transmitted to the programmable amplifier through two interfaces AIN+ and AIN-.

[0098] In one or more embodiments, the analog-to-digital converter is a Σ-Δ ADC.

[0099] In this embodiment, the analog-to-digital converter can be a Σ-Δ ADC. During implementation, an analog-to-digital converter with an integrated programmable amplifier, namely a programmable gain amplifier (PGA), can be used. For example, a data acquisition-analog-to-digital converter chip such as the MCP3561T can be used. After performing analog-to-digital conversion on an analog signal, the corresponding sampled data can be output via a serial peripheral interface (SPI).

[0100] In one or more embodiments, the signal acquisition circuit further includes a single chip microcomputer;

[0101] The single-chip microcomputer is electrically connected to a signal sampling module, and illustratively, the single-chip microcomputer is electrically connected to the analog-to-digital converter. The signal sampling module is configured to acquire an electrical signal between any two contact electrodes according to the multiplexer; the single-chip microcomputer is configured to perform a fast Fourier transform on the electrical signal collected by the signal sampling module to obtain a corresponding plurality of LFP amplitude-frequency curves, and select the optimal acquisition contact combination based on the principle of prioritizing the highest LFP signal β-band amplitude A and the lowest background noise.

[0102] The single chip microcomputer is configured to perform fast Fourier transform on the electrical signal collected by the signal sampling module to obtain a corresponding plurality of LFP amplitude-frequency curves, and to take the contact combination with the highest amplitude of the LFP signal in the β frequency band relative to the background noise as the optimal collection contact combination.

[0103] In this embodiment, the microcontroller and the analog-to-digital converter can be electrically connected via an SPI data interface. The microcontroller, which can be an MSP430, can perform an FFT on the sampled data provided by the analog-to-digital converter to obtain multiple corresponding LFP amplitude-frequency curves. The optimal acquisition contact combination is selected based on the principle of prioritizing the highest amplitude A (relative to the 150Hz external noise floor baseline) in the LFP signal's β frequency band (13-35Hz) and the lowest noise floor (i.e., within the frequency range greater than 150Hz).

[0104] As shown in FIG5 , the present application also provides a contact combination method, which is applied to the above-mentioned signal acquisition circuit and includes the following steps.

[0105] S110 , closing all channels of the analog switch to charge the sampling capacitor array through the multi-contact electrodes.

[0106] S120 , after a preset time, disconnect all channels of the analog switch, and control the multiplexer in turn to select any two sampling capacitors, so as to obtain sampling data between any two sampling capacitors in the sampling capacitor array through sampling by the signal sampling module.

[0107] S130 , performing fast Fourier transform on the sampling data between any two sampling capacitors to obtain a set of LFP amplitude-frequency curves.

[0108] S140 , selecting an element from the LFP amplitude-frequency curve set according to the principle that the LFP signal β frequency band amplitude is the highest and the background noise is the lowest, to obtain an optimal LFP amplitude-frequency curve.

[0109] S150 : Obtain an optimal acquisition contact point combination according to the optimal LFP amplitude-frequency curve.

[0110] In this embodiment, the contact combination method can be understood as a method for determining the optimal acquisition contact combination. Charging the sampling capacitor array via multiple contact electrodes can be understood as using the multiple contact electrodes as a collection medium to transmit the electrical signal from the nucleus region where each contact is located to the sampling capacitors. There is also a one-to-one correspondence between contacts and sampling capacitors, enabling targeted charging of the sampling capacitors. The electrical energy stored in each sampling capacitor should correspond to the local field electrical signal of the nucleus region to which it is connected.

[0111] The preset time can be set to different times according to different nucleus types, or can be set to a fixed value, and the specific value is not limited in the embodiments of this specification.

[0112] Assuming that the multi-contact electrode has N (≥2) contacts, the analog switch has N channels, and the sampling capacitor array includes N sampling capacitors C1 to C N, the multiplexer is composed of a multiplexer with an N-to-2 structure or two multiplexers with an N-to-1 structure. In one or more embodiments, the multiplexer includes a first multiplexer and a second multiplexer, and the signal sampling module includes a first voltage follower, a second voltage follower, a prefilter, a differential amplifier, a low-pass filter, a programmable amplifier, and an analog-to-digital converter. When determining the optimal acquisition contact combination without applying electrical stimulation, first close the N channels of the analog switch at the same time, and the N contacts of the multi-contact electrode respectively supply the multi-channel sampling capacitors C1 to C2 in the sampling capacitor array. N After the preset time, the N channels of the analog switch are disconnected at the same time, and the first multiplexer selects C H1 (corresponding to the sampling capacitor C1), is buffered by the first voltage follower and sent to one end of the pre-filter. The second multiplexer selects C H2 (corresponding to the sampling capacitor C2), is buffered by the second voltage follower and sent to the other end of the pre-filter. The pre-filter (essentially a band-pass filter) filters the signals received at both ends, amplifies them with a differential amplifier, filters them with a low-pass filter, and amplifies them with a programmable amplifier (PGA). The signals are then sent to an analog-to-digital converter such as a Σ-△ ADC for sampling to obtain a sampled data. Keep the first multiplexer selected C H1 (corresponding to sampling capacitor C1), modify the second multiplexer strobe C H3 (corresponding to sampling capacitor C3), and after back-end processing, a sampled data is obtained again, and the above process is repeated to obtain N*(N-1) / 2 combinations of sampled data. In the above cycle process, the selection combination of the first multiplexer and the second multiplexer cannot be repeated, that is, assuming that the first multiplexer has been selected by C H1 , the second multiplexer selects C H3 The combination of the processing to obtain a sample data, then the first multiplexer strobe C cannot appear again H1 , the second multiplexer selects C H3 combination, nor can the first multiplexer strobe C H3 , the second multiplexer selects C H1 By running an FFT on the sampled data from different combinations, we can obtain a set of N*(N-1) / 2 LFP amplitude-frequency curves. By prioritizing the LFP signal with the highest amplitude A (relative to the 150Hz external noise floor) in the β frequency band (13-35Hz) and the lowest noise floor, we can select the optimal LFP amplitude-frequency curve representing the optimal acquisition contact combination. This optimal LFP amplitude-frequency curve ultimately determines the optimal acquisition contact combination.

[0113] In one or more embodiments, the priority of the LFP signal with the highest amplitude in the β frequency band is higher than the priority of the background noise with the lowest amplitude.

[0114] In one or more embodiments, the LFP signal β frequency band is 13 to 35 Hz.

[0115] As shown in FIG6 , the present application further provides a stimulator, comprising an implantable pulse generator, electrode wires, and the above-mentioned signal acquisition circuit;

[0116] The implantable pulse generator is electrically connected to the multi-contact electrodes in the signal acquisition circuit through the electrode wire.

[0117] In this embodiment, after the optimal acquisition contact combination is determined by the signal acquisition circuit, the implantable pulse generator can apply corresponding electrical signals to the multi-contact electrodes in the signal acquisition circuit according to the optimal acquisition contact combination, thereby achieving real-time optimal optimization of electrical stimulation parameters.

[0118] As shown in FIG7 , the present application further provides an implantable medical system, which is applied to the above-mentioned signal acquisition circuit, including:

[0119] a startup module, configured to close all channels of the analog switch to charge the sampling capacitor array through the multi-contact electrode;

[0120] a sampling module configured to disconnect all channels of the analog switch after a preset time has passed, and to control the multiplexer to select any two sampling capacitors in a round-robin manner, so as to obtain sampling data between any two sampling capacitors in the sampling capacitor array through sampling by the signal sampling module;

[0121] A processing module is configured to perform fast Fourier transform on the sampling data between any two sampling capacitors to obtain a set of LFP amplitude-frequency curves;

[0122] A selection module is configured to select an element in the LFP amplitude-frequency curve set according to the principle that the LFP signal β frequency band amplitude is the highest and the background noise is the lowest, so as to obtain an optimal LFP amplitude-frequency curve;

[0123] The output module is configured to obtain an optimal acquisition contact point combination according to the optimal LFP amplitude-frequency curve.

[0124] The implantable medical system may include a stimulator implanted in the patient's body and a programmable device disposed outside the patient's body. Neuromodulation technology mainly involves implanting electrodes in specific structures (i.e., target points) in the body through stereotactic surgery, and the stimulator implanted in the patient's body emits discharge pulses to the target points through the electrodes, thereby regulating the electrical activity and function of the corresponding neural structures and networks, thereby improving symptoms and alleviating pain. Among them, the stimulator can be any one of an implantable neural electrical stimulation device, an implantable cardiac electrical stimulation system (also known as a pacemaker), an implantable drug delivery system (IDDS), and a lead adapter. Examples of implantable neurostimulation devices include Deep Brain Stimulation (DBS) systems, implantable Cortical Nerve Stimulation (CNS) systems, implantable Spinal Cord Stimulation (SCS) systems, implantable Sacral Nerve Stimulation (SNS) systems, and implantable Vagus Nerve Stimulation (VNS) systems. A stimulator may include an IPG, an extension lead, and an electrode lead. The IPG is placed in the patient's body, receives program-controlled instructions sent by a program-controlled device, relies on a sealed battery and circuits to provide controllable electrical stimulation energy to tissues in the body, and delivers one or two controllable, specific electrical stimulations to specific areas of tissue in the body through the implanted extension lead and electrode lead.

[0125] This application provides a signal acquisition circuit, a contact combination method, a stimulator and an implantable medical system, which can be used to explore the optimal acquisition position of electrophysiological signals of the patient's brain nuclei to achieve the optimal LFP acquisition effect, thereby realizing real-time optimal optimization of electrical stimulation parameters.

[0126] As shown in FIG8 , the present application further provides an implantable medical device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the above-mentioned contact combination method when executing the computer program.

[0127] The above embodiments should not limit the present application in any way, and any technical solutions obtained by equivalent replacement or equivalent conversion fall within the protection scope of the present application.

Claims

1. A signal acquisition circuit, comprising a multi-contact electrode, an analog switch, a sampling capacitor array, a multiplexer, and a signal sampling module; At least some of the contacts in the multi-contact electrode extend into the target nucleus during use; All the contacts in the multi-contact electrode are electrically connected to all the sampling capacitors in the sampling capacitor array one-to-one through the analog switch; Each sampling capacitor in the sampling capacitor array is electrically connected to the multiplexer, so that the multiplexer can select any two sampling capacitors; The multiplexer is electrically connected to the signal sampling module.

2. The signal acquisition circuit according to claim 1, wherein The multiplexer includes a first multiplexer and a second multiplexer; Each sampling capacitor in the sampling capacitor array is electrically connected to the first multiplexer and the second multiplexer respectively, and the output terminals of the first multiplexer and the second multiplexer are both connected to the signal sampling module.

3. The signal acquisition circuit according to claim 2, wherein, The signal sampling module includes a first voltage follower, a second voltage follower, a pre-filter, a differential amplifier, a low-pass filter, a programmable amplifier, and an analog-to-digital converter; The first multiplexer is electrically connected to the first voltage follower; The second multiplexer is electrically connected to the second voltage follower; The first voltage follower and the second voltage follower are respectively electrically connected to the pre-filter; The pre-filter is electrically connected to the differential amplifier; The differential amplifier is electrically connected to the low-pass filter; The low-pass filter is electrically connected to the programmable amplifier; The programmable amplifier is electrically connected to the analog-to-digital converter.

4. The signal acquisition circuit according to claim 3, wherein The multi-contact electrode includes N contacts, the analog switch includes N channels, the sampling capacitor array includes N sampling capacitors, and the first multiplexer and the second multiplexer are respectively N-to-1 multiplexers; One end of the Mth sampling capacitor is electrically connected to ground, and the other end of the Mth sampling capacitor is electrically connected to the Mth input terminal of the first multiplexer and the Mth input terminal of the second multiplexer respectively, and is electrically connected to the Mth contact of the multi-contact electrode through the Mth channel of the analog switch; Wherein, both M and N are integers, N≥2, N≥M≥1.

5. The signal acquisition circuit according to claim 3, wherein, The pre-filter includes a DC-blocking capacitor unit and a resistor-capacitor (RC) low-pass filtering unit; The first voltage follower and the second voltage follower are respectively electrically connected to the DC-blocking capacitor unit; The DC-blocking capacitor unit is electrically connected to the RC low-pass filtering unit; The RC low-pass filtering unit is electrically connected to the differential amplifier.

6. The signal acquisition circuit according to claim 3, wherein The differential amplifier is a fully differential chopper amplifier.

7. The signal acquisition circuit according to claim 3, wherein, The low-pass filter is a seventh-order Chebyshev filter.

8. The signal acquisition circuit according to claim 3, wherein, The analog-to-digital converter is a Σ-Δ analog-to-digital converter ADC.

9. The signal acquisition circuit according to claim 1, further comprising a single-chip microcomputer; The single-chip microcomputer is electrically connected to the signal sampling module, The signal sampling module is configured to obtain the electrical signal between any two contact electrodes according to the multiplexer; The single-chip microcomputer is configured to perform a fast Fourier transform on the electrical signals collected by the signal sampling module to obtain a corresponding plurality of local field potential (LFP) amplitude-frequency curves, and use the combination of contacts with the highest amplitude in the β frequency band of the LFP signal relative to the background noise as the optimal acquisition contact combination.

10. A contact combination method, applied to the signal acquisition circuit according to any one of claims 1 to 9, comprising: Closing all channels of the analog switch to charge the sampling capacitor array through the multi-contact electrode; After a preset time, disconnecting all channels of the analog switch and cyclically controlling the multiplexer to select any two sampling capacitors to sample the sampling data between any two sampling capacitors in the sampling capacitor array through the signal sampling module; Performing a fast Fourier transform on the sampling data between any two sampling capacitors respectively to obtain a set of local field potential (LFP) amplitude-frequency curves; Selecting the elements in the set of LFP amplitude-frequency curves according to the principle of the highest amplitude in the β frequency band of the LFP signal and the lowest background noise to obtain the optimal LFP amplitude-frequency curve; Obtaining the optimal acquisition contact combination according to the optimal LFP amplitude-frequency curve.

11. The contact combination method according to claim 10, wherein, The priority of the highest amplitude in the β frequency band of the LFP signal is higher than the priority of the lowest background noise.

12. The contact combination method according to claim 10, wherein, The β frequency band of the LFP signal is 13 - 35 Hz.

13. A stimulator, comprising an implantable pulse generator, an electrode lead wire, and the signal acquisition circuit according to any one of claims 1 to 9; The implantable pulse generator is electrically connected to the multi-contact electrode in the signal acquisition circuit through the electrode lead wire.

14. An implantable medical system, applied to the signal acquisition circuit according to any one of claims 1 to 9, comprising: A start module configured to close all channels of the analog switch to charge the sampling capacitor array through the multi-contact electrode; A sampling module configured to, after a preset time, disconnect all channels of the analog switch and cyclically control the multiplexer to select any two sampling capacitors to sample the sampling data between any two sampling capacitors in the sampling capacitor array through the signal sampling module; A processing module configured to perform a fast Fourier transform on the sampling data between any two sampling capacitors respectively to obtain a set of local field potential (LFP) amplitude-frequency curves; A selection module configured to select the elements in the set of LFP amplitude-frequency curves according to the principle of the highest amplitude in the β frequency band of the LFP signal and the lowest background noise to obtain the optimal LFP amplitude-frequency curve; An output module configured to obtain the optimal acquisition contact combination according to the optimal LFP amplitude-frequency curve.

15. An implantable medical device, comprising a memory and a processor, the memory storing a computer program, wherein, When the processor executes the computer program, it implements the contact combination method according to any one of claims 10 to 12.

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