Systems and methods for reducing artifacts in neurological response signals using customized recharge configurations

Abstract

A system or method according to embodiments of the present disclosure includes: generating, at a first time, a first electrical pulse; measuring a first neurological response to the first electrical pulse; generating, at a second time, a second electrical pulse with at least one characteristic different than the first electrical pulse; measuring a second neurological response to the second electrical pulse; and removing at least one artifact from at least one of the first neurological response and the second neurological response.

Description

SYSTEMS AND METHODS FOR REDUCING ARTIFACTS IN NEUROLOGICAL RESPONSESIGNALS USING CUSTOMIZED RECHARGE CONFIGURATIONSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of the filing date of provisional U.S. Patent Application No. 63 / 545,903 filed on October 26, 2023, the entire content of each of which is incorporated herein by reference.BACKGROUND

[0002] The present disclosure is generally directed to medical devices, and relates more particularly to neurological responses to stimulation.

[0003] Neuromodulation therapy may be carried out by sending an electrical signal generated by a pulse generator to a stimulation target, which may generate a response. The response may be recorded and used during the course of the neuromodulation therapy.BRIEF SUMMARY

[0004] Embodiments of the present disclosure beneficially enable artifact cancellation while also maintaining neurological signal timing by optimizing recharge parameters of stimulation signals delivered by an implantable device. While alternating polarity of stimulation signals enables artifact cancellation, such alternating can interfere with neurological response timings. To maintain neurological signal timing while also ensuring alternating polarity with respect to artifacts, the recharge parameters of a second stimulation signal can be adjusted to be different than the first, initial stimulation signal. The difference in recharge parameters enables better destructive interference of artifacts during superposition of the signals, while preserving neurological signal timing.

[0005] Example aspects of the present disclosure include:

[0006] A method according to at least one embodiment of the present disclosure comprises: generating, at a first time, a first electrical pulse; measuring a first neurological response to the first electrical pulse; generating, at a second time, a second electrical pulse with at least one characteristic different than the first electrical pulse; measuring a second neurological response to the second electrical pulse; and removing at least one artifact from at least one of the first neurological response and the second neurological response.

[0007] Any of the aspects herein, wherein at least one of the first neurological response and the second neurological response comprises an Evoked Compound Action Potential (ECAP) response or Compound Muscle Action Potential (CMAP) response.

[0008] Any of the aspects herein, wherein the at least one characteristic comprises an amount of time before a passive recharge phase that occurs after the second electrical pulse is paused to allow the measuring of the second neurological response.

[0009] Any of the aspects herein, wherein the at least one characteristic comprises a recharge mechanism.

[0010] Any of the aspects herein, wherein the first electrical pulse comprises an active recharge mechanism, and wherein the second electrical pulse comprises a passive recharge mechanism.

[0011] Any of the aspects herein, wherein the first electrical pulse comprises a passive recharge mechanism, and wherein the second electrical pulse comprises an active recharge mechanism.

[0012] Any of the aspects herein, wherein the at least one characteristic comprises at least one of an amplitude and a pulse width of a recharge phase of the second electrical pulse.

[0013] Any of the aspects herein, wherein the at least one characteristic comprises an amplitude of a recharge phase, and wherein an amplitude of a recharge phase of the first electrical pulse is greater than an amplitude of a recharge phase the second electrical pulse.

[0014] Any of the aspects herein, wherein the at least one characteristic comprises a pulse width of a recharge phase, and wherein a pulse width of a recharge phase of the first electrical pulse is less than a pulse width of a recharge phase the second electrical pulse.

[0015] Any of the aspects herein, wherein the removing the at least one artifact further comprises: combining the first neurological response and the second neurological response into a composite response.

[0016] Any of the aspects herein, wherein the combining the first neurological response and the second neurological response comprises weighting at least one of the first neurological response and the second neurological response.

[0017] Any of the aspects herein, wherein the composite response has reduced noise compared to the first neurological response and the second neurological response.

[0018] Any of the aspects herein, wherein the first neurological response and the second neurological response are generated by an anatomical element, and wherein the method further comprises: selecting at least one recharge parameter that increases a signal to noise ratio of the composite response.

[0019] A device according to at least one embodiment of the present disclosure comprises: a pulse generator configured to generate electrical pulses delivered to an anatomical element via a stimulation electrode; a processor; and a memory coupled with the processor and storing data thereon that, when processed by the processor, enable the processor to: cause the pulse generator to generate a first electrical pulse; receive a first neurological response of the anatomical element to the first electrical pulse; cause the pulse generator to generate a second electrical pulse with at least one characteristic different from the first electrical pulse; receive a second neurological response from the anatomical element to the second electrical pulse; and combine the first neurological response and the second neurological response into a composite response signal, wherein the composite response signal has less noise than the first neurological response and the second neurological response.

[0020] Any of the aspects herein, wherein at least one of the first neurological response and the second neurological response comprises an Evoked Compound Action Potential (ECAP) response or a Compound Muscle Action Potential (CMAP) of the anatomical element.

[0021] Any of the aspects herein, wherein the at least one characteristic comprises an amount of time before a passive recharge phase that occurs after the second electrical pulse is paused to allow measuring of the second neurological response.

[0022] Any of the aspects herein, wherein the at least one characteristic comprises a recharge mechanism.

[0023] Any of the aspects herein, wherein the first electrical pulse comprises an active recharge mechanism, and wherein the second electrical pulse comprises a passive recharge mechanism.

[0024] Any of the aspects herein, wherein the first electrical pulse comprises a passive recharge mechanism, and wherein the second electrical pulse comprises an active recharge mechanism.

[0025] Any of the aspects herein, wherein the at least one characteristic comprises at least one of an amplitude and a pulse width of a recharge phase of the second electrical pulse.

[0026] Any of the aspects herein, the at least one characteristic comprises an amplitude of a recharge phase, and wherein an amplitude of a recharge phase of the first electrical pulse is greater than an amplitude of a recharge phase the second electrical pulse.

[0027] Any of the aspects herein, wherein the at least one characteristic comprises a pulse width of a recharge phase, and wherein a pulse width of a recharge phase of the first electrical pulse is less than a pulse width of a recharge phase the second electrical pulse.

[0028] Any of the aspects herein, wherein the combining of the first neurological response and the second neurological response comprises weighting at least one of the first neurological response and the second neurological response.

[0029] Any of the aspects herein, wherein the data, when processed by the processor, further enable the processor to: select at least one recharge parameter that increases a signal to noise ratio of the composite response signal; cause the pulse generator to generate a third electrical pulse in accordance with the at least one recharge parameter; receive a third neurological response of the anatomical element to the third electrical pulse; and combine at least one of the first neurological response and the second neurological response with the third neurological response.

[0030] A device according to at least one embodiment of the present disclosure comprises: a pulse generator that generates electrical pulses; a stimulation electrode electrically coupled with the pulse generator that delivers the electrical pulses generated by the pulse generator to an anatomical element; a processor; and a memory coupled with the processor and storing data thereon that, when processed by the processor, enable the processor to: receive a first neurological signal from the anatomical element in response to a first electrical pulse generated by the pulse generator and delivered by the stimulation electrode; receive a second neurological signal from the anatomical element in response to a second electrical pulse generated by the pulse generator and delivered by the stimulation electrode, wherein at least one characteristic of the second electrical pulse is different from the first electrical pulse; and combine the first neurological signal with the second neurological signal into a composite signal, wherein the composite signal has less noise than the first neurological signal and the second neurological signal.

[0031] Any of the aspects herein, wherein at least one of the first neurological signal and the second neurological signal comprises an Evoked Compound Action Potential (ECAP) response or a Compound Muscle Action Potential (CMAP).

[0032] Any of the aspects herein, wherein the at least one characteristic comprises an amount of time before a passive recharge phase that occurs after the second electrical pulse is paused to allow measuring of the second neurological signal.

[0033] Any of the aspects herein, wherein the at least one characteristic comprises a recharge mechanism.

[0034] Any of the aspects herein, wherein the first electrical pulse comprises an active recharge mechanism, and wherein the second electrical pulse comprises a passive recharge mechanism.

[0035] Any of the aspects herein, wherein the first electrical pulse comprises a passive recharge mechanism, and wherein the second electrical pulse comprises an active recharge mechanism.

[0036] Any of the aspects herein, wherein the at least one characteristic comprises at least one of an amplitude and a pulse width of a recharge phase of the second electrical pulse.

[0037] Any of the aspects herein, wherein combining the first neurological signal and the second neurological signal comprises weighting at least one of the first neurological signal and the second neurological signal.

[0038] Any aspect in combination with any one or more other aspects.

[0039] Any one or more of the features disclosed herein.

[0040] Any one or more of the features as substantially disclosed herein.

[0041] Any one or more of the features as substantially disclosed herein in combination with any one or more other features as substantially disclosed herein.

[0042] Any one of the aspects / features / embodiments in combination with any one or more other aspects / features / embodiments .

[0043] Use of any one or more of the aspects or features as disclosed herein.

[0044] It is to be appreciated that any feature described herein can be claimed in combination with any other feature(s) as described herein, regardless of whether the features come from the same described embodiment.

[0045] The details of one or more aspects of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques described in this disclosure will be apparent from the description and drawings, and from the claims.

[0046] The phrases “at least one”, “one or more”, and “and / or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and / or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together. When each one of A, B, and C in the above expressions refers to an element, such as X, Y, and Z, or class of elements, such as XI -Xn, Yl-Ym, and Zl-Zo, the phrase is intended to refer to a single element selected from X, Y, and Z, a combination of elements selected from the same class (e.g., XI and X2) as well as a combination of elements selected from two or more classes (e.g., Y1 and Zo).

[0047] The term “a” or “an” entity refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, and “having” can be used interchangeably.

[0048] The preceding is a simplified summary of the disclosure to provide an understanding of some aspects of the disclosure. This summary is neither an extensive nor exhaustive overview of thedisclosure and its various aspects, embodiments, and configurations. It is intended neither to identify key or critical elements of the disclosure nor to delineate the scope of the disclosure but to present selected concepts of the disclosure in a simplified form as an introduction to the more detailed description presented below. As will be appreciated, other aspects, embodiments, and configurations of the disclosure are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below.

[0049] Numerous additional features and advantages of the present disclosure will become apparent to those skilled in the art upon consideration of the embodiment descriptions provided hereinbelow.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0050] The accompanying drawings are incorporated into and form a part of the specification to illustrate several examples of the present disclosure. These drawings, together with the description, explain the principles of the disclosure. The drawings simply illustrate preferred and alternative examples of how the disclosure can be made and used and are not to be construed as limiting the disclosure to only the illustrated and described examples. Further features and advantages will become apparent from the following, more detailed, description of the various aspects, embodiments, and configurations of the disclosure, as illustrated by the drawings referenced below.

[0051] Fig. 1 A is a diagram of aspects of a system according to at least one embodiment of the present disclosure;

[0052] Fig. IB is a block diagram of additional aspects of the system according to at least one embodiment of the present disclosure;

[0053] Fig. 2 is a diagram of leads and electrodes according to at least one embodiment of the present disclosure;

[0054] Fig. 3A depicts aspects of delivering a first stimulation signal according to at least one embodiment of the present disclosure;

[0055] Fig. 3B depicts aspects of delivering a second stimulation signal according to at least one embodiment of the present disclosure;

[0056] Fig. 3C depicts a composite signal according to at least one embodiment of the present disclosure;

[0057] Fig. 4 depicts aspects of delivering stimulation signals with different recharge parameters according to at least one embodiment of the present disclosure;

[0058] Fig. 5 depicts example data from recording electrodes according to at least one embodiment of the present disclosure;

[0059] Fig. 6 depicts example data from recording electrodes according to at least one embodiment of the present disclosure;

[0060] Fig. 7 depicts example data from recording electrodes according to at least one embodiment of the present disclosure;

[0061] Fig. 8 is a flowchart according to at least one embodiment of the present disclosure; and

[0062] Fig. 9 is a flowchart according to at least one embodiment of the present disclosure.DETAILED DESCRIPTION

[0063] It should be understood that various aspects disclosed herein may be combined in different combinations than the combinations specifically presented in the description and accompanying drawings. It should also be understood that, depending on the example or embodiment, certain acts or events of any of the processes or methods described herein may be performed in a different sequence, and / or may be added, merged, or left out altogether (e.g., all described acts or events may not be necessary to carry out the disclosed techniques according to different embodiments of the present disclosure). In addition, while certain aspects of this disclosure are described as being performed by a single module or unit for purposes of clarity, it should be understood that the techniques of this disclosure may be performed by a combination of units or modules associated with, for example, a processor and / or a medical device.

[0064] In one or more examples, the described methods, processes, and techniques may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. Alternatively or additionally, functions may be implemented using machine learning models, neural networks, artificial neural networks, or combinations thereof (alone or in combination with instructions). Computer- readable media may include non-transitory computer-readable media, which corresponds to a tangible medium such as data storage media (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer).

[0065] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors (e.g., Intel Core i3, i5, i7, or i9 processors; Intel Celeron processors; Intel Xeon processors; Intel Pentium processors; AMD Ryzen processors; AMDAthlon processors; AMD Phenom processors; Apple A10 or 10X Fusion processors; Apple Al l, A12, A12X, A12Z, or Al 3 Bionic processors; or any other general purpose microprocessors), graphics processing units (e.g., Nvidia GeForce RTX 2000-series processors, Nvidia GeForce RTX 3000-series processors, AMD Radeon RX 5000-series processors, AMD Radeon RX 6000-series processors, or any other graphics processing units), application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor” as used herein may refer to any of the foregoing structure or any other physical structure suitable for implementation of the described techniques. Also, the techniques could be fully implemented in one or more circuits or logic elements.

[0066] Before any embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The disclosure is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Further, the present disclosure may use examples to illustrate one or more aspects thereof. Unless explicitly stated otherwise, the use or listing of one or more examples (which may be denoted by “for example,” “by way of example,” “e.g.,” “such as,” or similar language) is not intended to and does not limit the scope of the present disclosure.

[0067] Systems and methods to reduce sensing artifacts are of interest for spinal cord stimulation (SCS), Deep Brain Stimulation (DBS), and Pelvic Health (PH) products, to enable closer and more flexible sense / stimulate configurations. Alternating polarity stimulation can be used to effectively cancel stimulation artifacts in SCS, PH, and CI implants. However, while the alternating polarity approach is effective in cancelling out artifacts, the approach can have a negative impact on the Evoked Compound Action Potential (ECAP) amplitude and signal-to-noise ratio (SNR). Since the ECAP may be recorded after each alternating polarity stimulation, after two polarized stimulations the recorded signal can be averaged. Due to the opposite polarity of the stimulation signal, the artifacts in the first signal have the opposite sign of the artifacts in the second signal, such that the artifacts cancel when the signals are averaged. However, some biological signals (such as ECAPs) are initiated primarily by the first cathodic phase of the first stimulation signal. Since the alternating of polarity changes the location on the anatomical element that experiences the cathodic phase, the ECAP timing varies for each alternating pulse. This may result in reduction or even cancellation ofneural signals depending on how the two recordings are superimposed or combined. In other words, the alternating polarity, while effective in reducing artifact presence, may also result in a reduced SNR. While the active recharge of the implantable device can be adjusted to optimize for artifact cancellation, hardware limitations may make it difficult to deliver an optimized recharge value. Systems and methods according to the present disclosure deliver electrical signals that optimize for artifact cancellation while also maintaining the ECAP timing.

[0068] It is to be understood that, while examples of ECAPs are discussed herein, any other type of sensed stimulation such as a Compound Muscle Action Potential (CMAP) response may be generated and recorded. Moreover, the sensing of ECAP responses, CMAP responses, and / or the like may occur in or under various medical or therapeutic applications, such as during SCS applications, DBS applications, PH applications, combinations thereof, and / or the like.

[0069] According to example embodiments of the present disclosure, the recharge parameters of the stimulation device may be adjusted to achieve an optimized recharge ratio that enables artifact cancellation while also maintaining ECAP timing across multiple alternating polarity stimulations. By manipulating the recharge parameters (e.g., amplitude, pulse width, etc.) of the stimulation signal during active recharge (which may include features of passive recharge), passive recharge, or a hybrid recharge that implements both active and passive recharge, the artifact may alternate in sign while the ECAP timing remains the same. For example, during passive recharge the duration of the passive recharge prior to sensing a neural signal (e.g., an ECAP, a CMAP, etc.) may be manipulated. In other words, the passive recharge may be truncated, paused, or otherwise stopped after a certain period of time to enable recording electrodes to measure the neural signal. As another example, a first stimulation may operate with passive recharge, and a second later stimulation may operate with passive recharge (or vice versa). The stimulations may then be summed together to perform artifact cancellation.

[0070] According to example embodiments of the present disclosure, various recharge configurations may be implemented by delivering a series of stimulations to a target anatomical element, each stimulation having a different recharge configuration. The differences in the recharge configurations result in alternating artifact amplitudes, while the timing for sensing the ECAP response remains the same. The average of the recharge configurations may then minimize artifacts while producing a better ECAP measurement, increasing the SNR of the signal. In some examples, a weighted average of the signals may be used to minimize the artifact. In some examples, the mathematical features of the artifacts (e.g., ratio of slopes, area under the curve, etc.) may be used to adjust the recharge parameters. In cases where the optimal recharge configuration can be deliveredby the hardware, the optimal recharge configuration may be selected and used for generating ECAP responses. If the hardware is not capable of delivering the optimal recharge configuration, the hardware may be configured to deliver stimulation with a recharge configuration closest to the optimal ratio as the hardware is able.

[0071] Embodiments of the present disclosure provide technical solutions to one or more of the problems of (1) shifted ECAP timings in alternating polarity stimulations, (2) high noise signals, and (3) hardware limitations in generating stimulation signals.

[0072] Turning first to Figs. 1 A-1B, aspects of a system 100 according to at least one embodiment of the present disclosure are shown. The system 100 may be used to provide electrical signals for a patient and / or to carry out one or more other aspects of one or more of the methods disclosed herein. For example, the system 100 may include an implantable medical device (IMD) 112 that may be configured to generate a current or electrical signal, such as a signal capable of stimulating a signal or response from a target anatomical element. The system 100 also includes an external device 136 that can be used to program, command, or otherwise control the IMD 112. The IMD 112 may generate, for example, a current or electrical signal capable of stimulating an ECAP response from one or more nerves or an LFP. In other examples, the IMD 112 may generate stimulations proximate the sacral nerve, within the brain, and / or proximate the peripheral nerves in order to perform SCS, sacral neuromodulation (SNM), DBS, peripheral nerve stimulation (PNS), combinations thereof, and / or the like. The IMD 112 depicted in Fig. 1 A comprises a first lead 116A and a second lead 116B implanted near or on a spinal cord 104 of a patient 102. In some cases, the IMD 112 may have an additional or alternative number of leads 116. The leads 116A, 116B may be implanted on or near any target anatomical element (e.g., on or near any organ, anatomical tissue, anatomical element, nerve, combinations thereof, etc.). In some cases, the leads 116A, 116B may be implanted in the epidural space between the spinal cord and the vertebrae. Once implanted, the leads 116A, 116B may provide electrical signals from the IMD 112 to the target anatomical element. The IMD 112 may be implantable in a patient or may be external to the patient, such as during testing of the leads 116A, 116B.

[0073] In some examples, the leads 116A, 116B may provide the electrical signals to respective nerves via electrodes 124 that are connected to the nerves (e.g., sutured in place, wrapped around the nerves, etc.). In some examples, the leads 116A, 116B may be referenced as cuff electrodes or may otherwise include the cuff electrodes (e.g., at an end of the leads 116A, 116B not connected or plugged into the IMD 112). Additionally or alternatively, while shown as physical wires that providethe connection between the IMD 112 and the one or more nerves, the electrodes may provide the electrical signals to the one or more nerves wirelessly (e.g., with or without the IMD 112).

[0074] The electrodes 124 may comprise stimulating electrodes (e.g., electrodes configured to stimulate a target anatomical element) or recording electrodes (e.g., electrodes configured to record a physiological response to the stimulation). Example electrodes 124 will be described in further detail in Fig. 2. In some cases, both the first lead 116A and the second lead 116B comprise both stimulating electrodes and recording electrodes. In other cases, the first lead 116A comprises stimulating electrodes while the second lead 116B comprises recording electrodes (or vice versa). In some examples, the recording electrode may record or measure the ECAP based on stimulations delivered by the stimulating electrode, which ECAP may be used to regulate or adjust the electrical signal generated by the IMD 112. Such adjustments to the delivered electrical signal may beneficially enhance the therapy delivered by the IMD 112.

[0075] With reference to Fig. IB, the IMD 112 comprises a memory 106, a communication interface 108, a processor 120, the leads 116A, 116B, one or more sensors 128, and one or more pulse generators 132. IMDs according to other examples of the present disclosure may comprise additional or alternative components than the IMD 112.

[0076] The processor 120 of the IMD 112 may be any processor described herein or any similar processor. The processor 120 may be configured to execute instructions stored in the memory 106, which instructions may cause the processor 120 to carry out one or more computing steps utilizing or based on data received from the leads 116A, 116B, the database 130, the cloud 134, and / or the external device 136. The processor 120 may be or comprise one or more digital signal processors (DSPs), general purpose microprocessors (e.g., Intel Core i3, i5, i7, or i9 processors; Intel Celeron processors; Intel Xeon processors; Intel Pentium processors; AMD Ryzen processors; AMD Athlon processors; AMD Phenom processors; Apple A10 or 10X Fusion processors; Apple Al l, Al 2, A12X, A12Z, or Al 3 Bionic processors; or any other general purpose microprocessors), graphics processing units (e.g., Nvidia GeForce RTX 2000-series processors, Nvidia GeForce RTX 3000- series processors, AMD Radeon RX 5000-series processors, AMD Radeon RX 6000-series processors, or any other graphics processing units), application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry.

[0077] The memory 106 may be or comprise RAM, DRAM, SDRAM, other solid-state memory, any memory described herein, or any other tangible, non-transitory memory for storing computer- readable data and / or instructions. The memory 106 may store information or data useful for completing, for example, any step of the methods 800 and / or 900 described herein, or of any othermethods. The memory 106 may store, for example, instructions and / or machine learning models that support one or more functions of the IMD 112. For instance, the memory 106 may store content (e.g., instructions and / or machine learning models) that, when executed by the processor 120, cause the leads 116A, 116B to apply an electrical signal to a respective target anatomical element, cause the leads 116A, 116B to record response signals from the respective target anatomical element, and / or cause the processor 120 to process the response signals.

[0078] The content of the memory 106, if provided as in instruction, may, in some embodiments, be organized into one or more applications, modules, packages, layers, or engines. Alternatively or additionally, the memory 106 may store other types of content or data (e.g., machine learning models, artificial neural networks, deep neural networks, etc.) that can be processed by the processor 120 to carry out the various method and features described herein. Thus, although various contents of memory 106 may be described as instructions, it should be appreciated that functionality described herein can be achieved through use of instructions, algorithms, and / or machine learning models. The data, algorithms, and / or instructions may cause the processor 120 to manipulate data stored in the memory 106 and / or received from or via the leads 116A, 116B, the database 130, the cloud 134, and / or the external device 136.

[0079] The communication interface 108 may be used for receiving data or other information from an external source (such as the database 130, the cloud 134, the external device 136, and / or any other system or component not part of the system 100), and / or for transmitting instructions, data, or other information to an external system or device (e.g., the database 130, the cloud 134, the external device 136, and / or any other system or component not part of the system 100). The communication interface 108 may comprise one or more wired interfaces (e.g., a USB port, an Ethernet port, a Firewire port) and / or one or more wireless transceivers or interfaces (configured, for example, to transmit and / or receive information via one or more wireless communication protocols such as 802.11a / b / g / n, Bluetooth, NFC, ZigBee, and so forth). In some embodiments, the communication interface 108 may be useful for enabling the IMD 112 to communicate with one or more other processors 120 or external devices 136, whether to transmit information related to ECAP signals or for any other reason.

[0080] The sensors 128 may be or comprise sensing elements that detect values of a respective patient parameter, such as the posture of the patient 102. The sensors 128 may be or comprise one or more gyroscopes, accelerometers, chemical sensors, temperature sensors, pressure sensors, combinations thereof, and / or the like. The sensors 128 may generate information and send such information to one or more components of the system 100, such as to the memory 106, the database130, and / or the external device 136. In some cases, the processor 120 may process such information, and adjust the parameters of the electrical stimulations generated by the IMD 112 accordingly. For example, the sensors 128 may detect increased patient activity (e.g., the patient 102 has stood up), and the processor 120 may cause the IMD 112 to increase the frequency at which the electrical stimulations are delivered to the patient 102.

[0081] The pulse generator 132 may be configured to generate an electrical stimulation signal (e.g., a current) that is passed into the target anatomical element. The pulse generator 132 may generate the current in accordance with one or more electrical stimulation parameters. The electrical stimulation signal may be a continuous-time signal. The pulse generator 132 may be controlled by signals sent from the processor 120. The electrical stimulation signal generated by the pulse generator 132 may propagate through the leads 116A, 116B and may be applied to the target surgical site or anatomical element through the electrodes 124. It is to be understood that, while a single pulse generator 132 is discussed herein, the pulse generator 132 may comprise multiple different pulse generators or other pulse generating circuitry capable of generating an electrical pulse.

[0082] As noted above, the external device 136 may be a device external to the IMD 112 capable of programming, commanding, or otherwise controlling the IMD 112. The external device 136 comprises a user interface 110, a communication interface 140, a processor 144, and a memory 148. External devices according to other examples of the present disclosure may comprise additional or alternative components to those shown in the external device 136.

[0083] The user interface 110 may be or comprise a keyboard, mouse, trackball, monitor, television, screen, touchscreen, and / or any other device for receiving information from a user and / or for providing information to a user. The user interface 110 may be used, for example, to receive a user selection or other user input regarding any step of any method described herein. The user interface 110 may be used in some cases to select one or more parameters for the electrodes (or other components of the IMD 112) including, but not limited to, selecting whether an electrode is active or inactive, recharge parameters after a stimulation has been applied, and the like. Notwithstanding the foregoing, any required input for any step of any method described herein may be generated automatically by the system 100 (e.g., by the processor 120 or another component of the system 100) or received by the system 100 from a source external to the system 100. In some embodiments, the user interface 110 may be useful to allow a user to modify instructions to be executed by the processor 120 according to one or more embodiments of the present disclosure, and / or to modify or adjust a setting of other information displayed on the user interface 110 or corresponding thereto.

[0084] Although the user interface 110 is shown as part of the external device 136, in some examples, the external device 136 may utilize a user interface 110 that is housed separately from one or more remaining components of the external device 136. In some examples, the user interface 110 may be located proximate one or more other components of the external device 136, while in other embodiments, the user interface 110 may be located remotely from one or more other components of the external device 136.

[0085] The communication interface 140 may be similar to or the same as any communication interface discussed herein (e.g., the communication interface 108). The communication interface 140 may be configured to receive data or other information from an external source (such as the IMD 112, database 130, the cloud 134, and / or any other system or component not part of the system 100), and / or for transmitting instructions, data, or other information to an external system or device (e.g., the IMD 112, the database 130, the cloud 134, and / or any other system or component not part of the system 100).

[0086] The processor 144 may be similar to or the same as any processor discussed herein (e.g., the processor 120). The processor 144 may be configured to execute instructions stored in the memory 148, which instructions may cause the processor 144 to carry out one or more computing steps utilizing or based on data received from the IMD 112, the database 130, the cloud 134, and / or any other component of the system 100 or component external to the system 100.

[0087] The memory 148 may be similar to or the same as any memory discussed herein (e.g., the memory 106). The memory 148 may be or comprise RAM, DRAM, SDRAM, other solid-state memory, any memory described herein, or any other tangible, non-transitory memory for storing computer- readable data and / or instructions. The memory 106 may store information or data useful for completing, for example, one or more steps of the method 800 and / or 900 described herein, or of any other methods.

[0088] The database 130 may store information such as patient data; results of a stimulation procedure; stimulation parameters (including recharge parameters, electrical signal parameters, electrode parameters, and / or the like); threshold values that can used for optimizing recharge parameters associated with the IMD 112, for weighting measured neurological signals, combinations thereof, etc.; and / or the like. The database 130 may be configured to provide any such information to the IMD 112, the external device 136, and / or any other device of the system 100 or external to the system 100, whether directly or via the cloud 134. In some examples, the database 130 may be or comprise part of a hospital image storage system, such as a picture archiving and communicationsystem (PACS), a health information system (HIS), and / or another system for collecting, storing, managing, and / or transmitting electronic medical records.

[0089] The cloud 134 may be or represent the Internet or any other wide area network. The IMD 112 and / or the external device 136 may be respectively connected to the cloud 134 via the communication interface 108 and the communication interface 140, using a wired connection, a wireless connection, or both. In some embodiments, the IMD 112 and / or the external device 136 may communicate with the database 130, one another, and / or an external device via the cloud 134.

[0090] The system 100 or similar systems may be used, for example, to carry out one or more aspects of any of the methods 800 and / or 900 described herein. The system 100 or similar systems may also be used for other purposes.

[0091] With reference to Fig. 2, the leads 116A, 116B and electrodes 124 are shown in accordance with embodiments of the present disclosure. The electrodes 124 may be arranged in different pattens on the leads 116A, 116B depending on the type of IMD 112, the type of therapy applied to the patient 102, characteristics of the stimulation signals to be delivered to the target anatomical element, combinations thereof, and / or the like. While the leads 116A, 116B illustrated in Fig. 2 each comprise eight electrodes, an additional or alternative number of electrodes may be present. The electrodes 124 may be connected to one or more components of the system 100, such as to the memory 106, the processor 120, the database 130, the cloud 134, and / or the external device 136 or components thereof. Such connection may enable signals captured by the electrodes 124 to be relayed to one or more other components of the system 100.

[0092] The electrodes 124 comprise a first electrode 204, a second electrode 208, a third electrode 212, and a fourth electrode 216. As previously noted, the electrodes may be used as stimulating electrodes (e.g., electrodes configured to stimulate a target anatomical element) or recording electrodes (e.g., electrodes configured to record a physiological response to the stimulation). For example, the first electrode 204 and the second electrode 208 may be used as stimulating electrodes that deliver a stimulation signal to the target anatomical element, while the third electrode 212 and the fourth electrode 216 may be recording electrodes that sense a response (e.g., an ECAP response, a CMAP response, etc.) from the target anatomical element. In some examples, such as when the IMD 112 delivers an alternating polarity stimulation, the electrodes may alternate as a cathode / anode pair. For example, in a cathodic leading phase, the first electrode 204 may operate as the cathode and the second electrode 208 may operate as the anode. During the recharge phase that follows the cathodic leading phase, the first electrode 204 may switch to operating as the anode while the second electrode 208 operates as the cathode.

[0093] With reference to Figs. 3A-3B, aspects of stimulation of a target anatomical element 304 using the IMD 112 are shown in accordance with embodiments of the present disclosure. The stimulation signal applied by the electrodes 124 of the IMD 112 may be a signal capable of generating a neurological response (e.g., an ECAP response) in the target anatomical element 304, which may be recorded and used, for example, to verify or adjust a therapy delivered by the IMD 112.

[0094] Fig. 3 A shows the first lead 116A positioned near or on the first electrode 204, such that the first electrode 204 and the second electrode 208 are able to deliver a stimulation signal to the target anatomical element 304. The first electrode 204 may operate as the cathode, while the second electrode 208 may operate as the anode (or vice versa). The first electrode 204 and the second electrode 208 may deliver a cathodic-leading stimulation 308 to the target anatomical element 304. The cathodic-leading stimulation 308 comprises a leading phase 312 and a recharge phase 316. The leading phase 312 occurs when the first electrode 204 and the second electrode 208 pass the current generated by the pulse generator 132 through the target anatomical element 304. After the stimulation, the recharge phase 316 begins. During the recharge phase 316, one or more capacitors in the IMD 112 are connected to a current source of opposite polarity to the stimulation current generated by the pulse generator 132 in the leading phase 312. The recharge phase 316 functions as a charge balancing phase for the IMD 112. As a result, the IMD 112 discharges current into the target anatomical element 304 in the opposite direction of the leading phase 312. Additionally or alternatively, the IMD 112 may undergo passive recharge, where the one or more capacitors are connected to ground or to a common reference to perform charge balancing. In some cases, the IMD 112 may undergo passive recharge exclusively (e.g., the IMD 112 does not undergo active recharge), or the IMD 112 may undergo a combination of active recharge and passive recharge.

[0095] Once the recharge phase 316 occurs, the target anatomical element 304 may generate a neurological response 324 to the stimulation. In some examples, the neurological response 324 may be an ECAP response, a CMAP response, or the like. The neurological response 324 may occur at a time tl within a sensing window 320. The sensing window 320 may be or comprise a time where one or more recording electrodes 124 of the leads 116A, 116B are turned on or enabled, such that the neurological response 324 can be recorded by the recording electrodes 124 and sent to the memory 106, the processor 120, the external device 136, and / or the like. During the sensing window 320, the recording electrodes 124 may also sense non-neural signals, such as a sensing artifact 328. In some cases, the sensing window 320 may occur during the recharge phase 316 (e.g., the IMD 112 is still recharging when the target anatomical element generates a neurological response). In such cases, therecharge phase 316 may be truncated, paused, or otherwise stopped to enable the recording electrodes 124 to record the neurological response 324. Once the sensing window 320 has passed, the recharge phase 316 may resume or continue. In some examples, the truncating or pausing of the recharge phase 316 (which may be passive) may comprise the capacitors in the IMD 112 remaining loosely connected to ground or a common reference via a high impedance connection (e.g., a connection with impedance greater than 1 Megaohm (MO)). In other words, in some examples the truncating or pausing may not result in the capacitors of the IMD 112 being disconnected from the ground or common reference, but may instead be loosely connected to a large impedance.

[0096] To account for the sensing artifact 328, the IMD 112 may generate another, opposite polarity stimulation at a later time. This opposite polarity may be an anodic-leading stimulation 332. In the anodic-leading stimulation 332, the first electrode 204 and the second electrode 208 may switch polarity from the polarity used to deliver the cathodic-leading stimulation 308. In other words, if the first electrode 204 functioned as the cathode and the second electrode 208 function as the anode when delivering the cathodic-leading stimulation 308, the first electrode 204 now functions as the anode and the second electrode 208 now functions as the cathode to deliver the anodic-leading stimulation 332. Similar to the cathodic-leading stimulation 308, the anodic-leading stimulation 332 comprises a leading phase 336 and a recharge phase 340. The leading phase 336 may be similar to or the same as the leading phase 312 except the polarity of the current may be switched, resulting in an opposite electric potential in the leading phase 336 as compared to the leading phase 312. The recharge phase 340 may be similar to or the same as the recharge phase 316 except the polarity of the current may be flipped, resulting in an opposite electric potential in the recharge phase 340 as compared to the recharge phase 316.

[0097] Similar to the cathodic-leading stimulation 308, the delivery of the anodic-leading stimulation 332 may cause the target anatomical element 304 to generate a neurological response 348 at a time t2 within a sensing window 344. In some examples, the neurological response 348 may be an ECAP response. The sensing window 344 may be or comprise a time where one or more recording electrodes 124 of the leads 116A, 116B are turned on or enabled, such that the neurological response 348 can be recorded by the recording electrodes 124 and sent to the memory 106, the processor 120, the external device 136, and / or the like. During the sensing window 344, the recording electrodes 124 may also sense non-neural signals, such as a sensing artifact 352.

[0098] With reference to Fig. 3C, the data recorded by the electrodes 124 during the sensing window 320 and the sensing window 344 may be overlaid or otherwise combined into a composite signal. As shown in Fig. 3C, the composite signal may be overlaid with respect to a time axis 356,which may correspond to the same units of time as the sensing window 320 and the sensing window 344. The combination of the data may result in the sensing artifact 328 and the sensing artifact 352 having equal and opposite magnitudes (e.g., due to the alternating polarity of the cathodic-leading stimulation 308 and the anodic-leading stimulation 332). These equal and opposite magnitudes may cancel out, such that the overall noise created by the sensing artifact 328 and the sensing artifact 352 is removed, reduced, or minimized. However, due to the differences in cathode location on the target anatomical element 304 during the cathodic-leading stimulation 308 and the anodic-leading stimulation 332, the timing of the neurological response 324 and the neurological response 348 may be different. For example, the neurological response 324 may have begun at time tl, while the neurological response 348 began at time t2. This difference in timing may result in destructive interference when the neurological response 324 and the neurological response 348 are combined together, reducing the SNR of the composite signal.

[0099] With reference to Fig. 4, a plurality of stimulating signals with various different recharge parameters are shown in accordance with embodiments of the present disclosure. To account for the difference in timing while also maintaining the alternating polarity artifacts (to enable artifact minimization when the neurological signals are combined) the IMD 112 may deliver stimulating signals with various different recharge parameters. The changing of the recharge parameters may be such that the artifacts in the signals are equal and opposite in magnitude, while the overall timing of sensing the neurological response is maintained to reduce the likelihood of destructive interference of the neurological signals when multiple neurological signals are combined.

[0100] As an example, the IMD 112 may deliver a first stimulation signal 404 to the target anatomical element 304, which first stimulation signal 404 may be similar to or the same as the cathodic-leading stimulation 308. The first stimulation signal 404 comprises a leading phase 408 and a recharge phase 412, both of which may be respective similar to or the same as the leading phase 312 and the recharge phase 316. The stimulation may cause the target anatomical element to generate a neurological response such as a neurological response 420, which is captured in a sensing window 416 by one or more electrodes of the IMD 112. The recording of the neurological response 420 by the electrodes may also comprise sensing artifact 424, which may be or comprise non- neurological noise. In some embodiments, the sensing window 416, the neurological response 420, and the sensing artifact 424 may be similar to or the same as the sensing window 320, the neurological response 324, and the sensing artifact 328, respectively.

[0101] The IMD 112 may then deliver a second stimulation signal 428 to the target anatomical element 304. The second stimulation signal 428 may be similar to the first stimulation signal 404 inthat the first stimulation signal 404 comprises a leading phase 432 and a recharge phase 436. However, unlike the stimulation discussed with respect to anodic-leading stimulation 332, the second stimulation signal 428 may be another cathodic-leading stimulation (as opposed to an anodic- leading stimulation). For example, the first electrode 204 and the second electrode 208 may be used by the IMD 112 to deliver both the first stimulation signal 404 and the second stimulation signal 428. As a result, instead of the cathode / anode pair swapping between stimulation signals, the cathode / anode pair remains the same. In other words, the first electrode 204 acts as the cathode and the second electrode 208 acts as the anode (or vice versa) for both the first stimulation signal 404 and the second stimulation signal 428. Since the cathode / anode pair remains the same, the timing of the resulting neurological response from the target anatomical tissue remains the same.

[0102] The recharge phase 436 of the second stimulation signal 428 may be similar to or the same as the recharge phase 316. In other words, the recharge phase 436 may occur when one or more capacitors in the IMD 112 are connected to a current source of opposite polarity to the stimulation current generated by the pulse generator 132 and delivered to the target anatomical tissue during the leading phase 432. The recharge phase 436 may have one or more parameters, characteristics, or aspects that are different from the recharge phase 412 of the first stimulation signal 404. For example, the recharge phase 436 may have a different amplitude (e.g., a greater amplitude or a lesser amplitude) that the recharge phase 412, a different pulse width (e.g., a larger pulse width or a smaller pulse width) than the recharge phase 412, a different period of time before a recharge phase (e.g., a passive recharge phase) is truncated or paused to measure a neurological response, a different recharge mechanism (e.g., the recharge phase 436 undergoes passive recharge, while the recharge phase 412 undergoes active recharge), combinations thereof, and / or the like. The recharge parameters of the recharge phase 436 may be manipulated by prematurely disconnecting one or more capacitors in the IMD 112 from the current source of opposite polarity to the stimulation current generated by the pulse generator 132 during the leading phase 432, by adjusting the amplitude of the current source of opposite polarity, combinations thereof, and / or the like.

[0103] After the recharge phase 436, the target anatomical element 304 may generate a neurological response 444 to the second stimulation signal 428, which may be measured and recorded within a sensing window 440 by the electrodes of IMD 112. The electrodes may also record a sensing artifact 448. Due to the adjustment of the recharge parameters of the recharge phase 436, the sensing artifact 448 may be equal and opposite in magnitude to the sensing artifact 424. As a result, when the neurological response 420 and the neurological response 444 are combined, the sensing artifact 424 and the sensing artifact 448 may experience destructive interference (e.g., theartifacts are cancelled out). Additionally, due to the cathodic-leading stimulation used in both the first stimulation signal 404 and the second stimulation signal 428, the timings of the neurological response 420 and the neurological response 444 (e.g., ECAP responses) may be similar or the same, reducing the likelihood of destructive interference between the neurological responses 420, 444 when combined.

[0104] Figs. 5-7 illustrate example data from recording electrodes for stimulations applied by the IMD 112 to a target anatomical element. It is to be understood that such examples are in no way limiting, and additional or alternative stimulations at various currents, amplitudes, pulse widths, etc. could be applied to the target anatomical element. In some cases, such as the example data shown in Fig. 5, the recharge (e.g., passive recharge) may be paused or blanked (as indicated by the “PRBlk” language in the legend of Fig. 5) during the sensing window to enable the recording electrodes to record the neurological response signal. After the neurological response signal has been recorded, the recharge may resume.

[0105] With reference to Fig. 5, a diagram of artifacts generated with various recharge parameters according to at least one embodiment of the present disclosure is shown. The data depicted in the graph may be or comprise sampling values (e.g., in microvolts (pV)) of data captured within a sensing window (e.g., sensing window 320, sensing window 344, etc.) after a target anatomical element has been stimulated with both a first stimulation signal and a second stimulation signal, with each stimulation signal having different recharge parameters. Various examples of the different recharge parameters comprise both stimulation signals have different recharge parameters (e.g., different amplitudes, different pulses widths, etc.), the first stimulation signal using active recharge and the second stimulation signal using passive recharge (or vice versa), both stimulation signals using passive recharge with different truncation timings (e.g., the passive recharge of the first stimulation signal is truncated at an earlier time than the passive recharge of the second stimulation signal), combinations thereof, and / or the like. The sampling may occur for a known or predetermined number of samples within the sensing window. For example, the recording electrodes may capture 50 samples within the sensing window.

[0106] The first curve 504 depicts sample values (e.g., measured voltage across the recording electrodes) when the first stimulation signal 404 (e.g., a 1.2 milliampere (mA) current with a pulse width of 200 micro seconds (ps)) is applied to the target anatomical element with a passive recharge that is blanked. The second curve 508 depicts the sample values when the second stimulation signal 428 is applied to the target anatomical element. As previously discussed, the recharge parameters of the second stimulation signal 428 may have at least one different parameter / characteristic / aspect / etc.than the recharge parameters of the first stimulation signal 404. As one example, the second curve 508 may depict data when the recharge phase 436 current is half (1 / 2) the amplitude of the recharge phase 412 current. The average curve 512 may represent the average of the first curve 504 and the second curve 508. As can be seen in the graph, the average curve 512 is close to zero in value, indicating that the first curve 504 and the second curve 508 (which correspond to cathodic-leading stimulations with different recharge parameters) have equal and opposite magnitudes. In some cases, the sample values may be associated with artifacts of the recorded neurological responses, enabling the system 100 to cancel the artifacts (e.g., using data processing performed by the processor 120, the processor 144, etc.).

[0107] With reference to Fig. 6, a diagram of artifacts generated with various recharge parameters according to at least one embodiment of the present disclosure is shown. The data depicted in the graph may be or comprise sampling values (e.g., in pV) of data captured within a sensing window (e.g., sensing window 320, sensing window 344, etc.) after a target anatomical element has been stimulated with both a first stimulation signal and a second stimulation signal, with each stimulation signal having different recharge parameters. For example, the recording electrodes may capture 50 samples within the sensing window.

[0108] The first curve 604 depicts sample values when the first stimulation signal 404 (e.g., a 5.5 mA signal at 200 ps) is applied to the target anatomical element. The second curve 608 may depict an application of the second stimulation signal 428 with passive recharge of the IMD 112 in the recharge phase 436 instead of an active recharge. Passive recharge may comprise connecting one or more capacitors of the IMD 112 to ground or to a common reference to perform charge balancing, as opposed to active recharge balancing where the capacitor(s) are connected to an opposite polarity current source. The third curve 612 may depict the average of the first curve 604 and the second curve 608. In other words, the third curve 612 may depict sample values when the first stimulation signal 404 implements an active recharge, and when the second stimulation signal 428 implements a passive recharge. The fourth curve 616 may depict sample values when the second stimulation signal 428 is applied to the target anatomical element. As previously discussed, the recharge parameters of the second stimulation signal 428 may have at least one different parameter / characteristic / aspect / etc. than the recharge parameters of the first stimulation signal 404. As one example, the second curve 608 may depict data when the amplitude of the recharge phase 436 current is half (1 / 2) the amplitude of recharge phase 412 current.

[0109] As can be seen in the graph of Fig. 6, the use of a passive recharge in the second stimulation signal 428 results in the third curve 612 reaching a value of zero after about sample 15,but in the first 15 samples the use of an active recharge with adjusted recharge parameters yields sample values closer to zero.

[0110] With reference to Fig. 7, a diagram of artifacts generated with various recharge parameters according to at least one embodiment of the present disclosure is shown. The data depicted in the graph may be or comprise sampling values (e.g., in pV) of data captured within a sensing window (e.g., sensing window 320, sensing window 344, etc.) after a target anatomical element has been stimulated with both a first stimulation signal and a second stimulation signal, with each stimulation signal having different recharge parameters. For example, the recording electrodes may capture 50 samples within the sensing window.

[0111] The first curve 704 depicts sample values when the first stimulation signal 404 (e.g., a 9.9 mA signal at 200 ps) is applied to the target anatomical element. The second curve 708 depicts the sample values when the second stimulation signal 428 is applied to the target anatomical element. As previously discussed, the recharge parameters of the second stimulation signal 428 may have at least one different parameter / characteristic / aspect / etc. than the recharge parameters of the first stimulation signal 404. In one example, the second curve 708 may depict data when the amplitude of the recharge phase 436 current is an eighth (1 / 8) of the amplitude of the recharge phase 412 current. The third curve 712 depicts an average of the first curve 704 and the second curve 708. The fourth curve 716 depicts the sample values when the second stimulation signal 428 is applied to the target anatomical element with a recharge phase 436 current at half the amplitude of the recharge phase 412 current. As can be seen in the graph of Fig. 7, both the third curve 712 and the fourth curve 716 oscillate around the zero value mark.

[0112] Fig. 8 depicts a method 800 that may be used, for example, to remove one or more artifacts from a stimulation response signal.

[0113] The method 800 (and / or one or more steps thereof) may be carried out or otherwise performed, for example, by at least one processor. The at least one processor may be the same as or similar to the processor 120 of the IMD 112 or the processor 144 of the external device 136 described above. The at least one processor may be part of the IMD 112, part of the external device 136, or part of a control unit in communication with the IMD 112 and / or the external device 136. A processor other than any processor described herein may also be used to execute the method 800. The at least one processor may perform the method 800 by executing elements stored in a memory such as the memory 106 or the memory 148. The elements stored in memory and executed by the processor may cause the processor to execute one or more steps of a function as shown in method 800. One or more portions of a method 800 may be performed by the processor executing any of thecontents of memory, such as applying an electrical signal(s) to a target anatomical element, causing leads (e.g., the leads 116A, 116B) to record response signals from the respective target anatomical element, processing the response signals, and / or any associated operations as described herein.

[0114] The method 800 comprises generating, at a first time, a first electrical pulse (step 804). The first electrical pulse may be generated by the IMD 112 (e.g., using the pulse generator 132). The first electrical pulse may, in some examples, be similar to or the same as the first stimulation signal 404. In some embodiments, the first electrical pulse may be generated by the IMD 112 based on instructions received from the external device 136. In some embodiments, the first electrical pulse may be generated in accordance with one or more parameters (e.g., stimulation parameters such as recharge parameters, electrical signal parameters, electrode parameters, and / or the like). The first electrical pulse may be delivered by one or more stimulation electrodes 124 of the IMD 112 to the target anatomical element 304.

[0115] The method 800 also comprises measuring a first neurological response to the first electrical pulse (step 808). After the first electrical pulse has stimulated the target anatomical element 304, the target anatomical element 304 may generate the first neurological response. The first neurological response may be similar to or the same as the neurological response 420, and may be or comprise any type of neurological response to the stimulation created by delivery of the first electrical pulse. The first neurological response may be measured by one or more sensing electrodes 124 of the IMD 112.

[0116] The method 800 also comprises generating, at a second time, a second electrical pulse with at least one characteristic different than the first electrical pulse (step 812). The second electrical pulse may, in some examples, be similar to or the same as the second stimulation signal 428. In some embodiments, the second electrical pulse may be generated by the IMD 112 based on instructions received from the external device 136. In some embodiments, the second electrical pulse may be generated in accordance with one or more parameters (e.g., stimulation parameters such as recharge parameters, electrical signal parameters, electrode parameters, and / or the like). The second electrical pulse may be delivered by one or more stimulation electrodes 124 of the IMD 112 to the target anatomical element 304.

[0117] The second electrical pulse has at least one characteristic (e.g., amplitude, pulse width, etc.) different than the first pulse. For example, the recharge parameters associated with the recharge phase of the second electrical pulse may be different than the recharge parameters associated with the recharge phase of the first electrical pulse. The amplitude of the recharge phase current of the second electrical pulse may be different (e.g., a greater current or a lesser current) than the amplitudeof the recharge phase current of the first electrical pulse. Additionally or alternatively, the pulse width of the recharge phase current of the second electrical pulse may be different (e.g., a greater pulse width or a lesser pulse width) than the pulse width of the recharge phase current of the first electrical pulse. As another example, the recharge phase of the second electrical pulse may be paused or truncated at a different time interval (e.g., more quickly, less quickly) than a corresponding time interval for the first electrical pulse. In another example, the first electrical pulse and the second electrical pulse may use different recharge mechanisms, such as when the first electrical pulse uses an active recharge phase and the second electrical pulse uses a passive recharge phase (or vice versa). It is to be understood that, while amplitude, pulse width, recharge phase truncation, and / or recharge mechanism are provided as examples, any other feature, characteristic, and / or parameter of the second electrical pulse may be modified (e.g., based on information from the external device 136) to be different than a corresponding feature, characteristic, and / or parameter of the first electrical pulse.

[0118] The method 800 also comprises measuring a second neurological response to the second electrical pulse (step 816). After the second electrical pulse has stimulated the target anatomical element 304, the target anatomical element 304 may generate the second neurological response. The second neurological response may be similar to or the same as the neurological response 444, and may be or comprise any type of neurological response to the stimulation created by delivery of the second electrical pulse. The second neurological response may be measured by one or more sensing electrodes 124 of the IMD 112.

[0119] The method 800 also comprises removing at least one artifact from at least one of the first neurological response and the second neurological response (step 820). The first neurological response and the second neurological response may be combined into a composite signal in order to reduce, cancel (e.g., via destructive interference), or otherwise minimize artifacts recorded in the first neurological response and the second neurological response. In some embodiments, the first neurological response and the second neurological response may be ECAP responses with similar timings due to the cathodic-leading phases of the first electrical pulse and the second electrical pulse. As a result, the combination of the first neurological response and the second neurological response may remove one or more artifacts from the composite signal using destructive interference, while preserving the ECAP responses.

[0120] The present disclosure encompasses embodiments of the method 800 that comprise more or fewer steps than those described above, and / or one or more steps that are different than the steps described above.

[0121] Fig. 9 depicts a method 900 that may be used, for example, to select optimized recharge parameters for an IMD 112.

[0122] The method 900 (and / or one or more steps thereof) may be carried out or otherwise performed, for example, by at least one processor. The at least one processor may be the same as or similar to the processor 120 of the IMD 112 or the processor 144 of the external device 136 described above. The at least one processor may be part of the IMD 112, part of the external device 136, or part of a control unit in communication with the IMD 112 and / or the external device 136. A processor other than any processor described herein may also be used to execute the method 900. The at least one processor may perform the method 900 by executing elements stored in a memory such as the memory 106 or the memory 148. The elements stored in memory and executed by the processor may cause the processor to execute one or more steps of a function as shown in method 900. One or more portions of a method 900 may be performed by the processor executing any of the contents of memory, such as applying an electrical signal(s) to a target anatomical element, causing leads (e.g., the leads 116A, 116B) to record response signals from the respective target anatomical element, processing the response signals, and / or any associated operations as described herein.

[0123] The method 900 comprises setting recharge parameters for a pulse generator (step 904). The set recharge parameters may be based on user input via the user interface 110 of the external device 136. In some embodiments, the recharge parameters may be based on predetermined or stored values from the database 130. The recharge parameters may then be sent from the external device 136 to the IMD 112 to program the IMD 112 to deliver electrical pulses in accordance with the recharge parameters.

[0124] The method 900 also comprises generating a set of electrical pulses in accordance with the recharge parameters (step 908). The set of electrical pulses may be similar to or the same as the first stimulation signal 404 and / or the second stimulation signal 428. The number of electrical pulses is not limited, and the pulse generator 132 may generate two, three, four, five, six, or more electrical stimulation signals. The electrical stimulation signals may conform with the set recharge parameters. In some embodiments, the recharge parameters for one or more electrical pulses may be different than the recharge parameters for one or more other electrical pulses. In some embodiments, the set of electrical pulses may be delivered concurrently using stimulation electrodes 124 of the IMD 112 to the target anatomical element 304, with sensing windows between each electrical pulse to detect neurological responses form the anatomical element, as discussed in the step 912 below.

[0125] The method 900 also comprises measuring a set of neurological responses in response to the set of electrical pulses (step 912). After delivery of each electrical pulse of the set of neurologicalpulses, the target anatomical element 304 may generate a neurological response. Each neurological response may be measured and recorded by one or more sensing electrodes 124 of the IMD 112.

[0126] The method 900 also comprises weighting one or more neurological responses of the set of neurological responses (step 916). Optionally, one or more neurological responses of the set of neurological responses may be weighted. Such weighting may impact the scale of the neurological response, as well as the scale of the non-neurological data (e.g., artifacts). The responses may be weighted to improve destructive interference of the non-neurological data when the neurological responses are combined into a composite signal.

[0127] The method 900 also comprises combining one or more neurological responses to create a composite signal (step 920). Proceeding from the step 916 (or from the step 912 in instances where the neurological responses are not weighted), one or more neurological responses may be combined into a composite signal. In some examples, the combination of neurological responses may reduce, minimize, or cancel the artifacts present in the neurological responses. In some embodiments, the composite signal may be similar to or the same as the average curve 512, the third curve 612, or the third curve 712. In embodiments where weighting was applied to one or more neurological responses, the composite signal may be mathematically adjusted to compensate for the weighting (e.g., if the neurological signals were scaled up during weighting, the composite signal may be scaled down accordingly to bring the magnitude of the composite signal in line with the magnitudes of the pre- weighted neurological responses).

[0128] The method 900 also comprises determining if the artifact is minimized (step 924). Based on the composite signal (or in some cases various combinations of the neurological responses of the set of neurological responses), the external device 136 may determine if the artifact has been minimized. The external device 136 may use the contents of the memory 148, which may comprise data that enable the processor 144 to perform data analysis on the composite signal. For example, the processor 144 may determine a ratio of the slopes of the curves representative of the artifacts and compare the ratio to a threshold value. The threshold value may be a predetermined threshold value (e.g., a value stored in the database 130). The threshold value may reflect the tolerance of artifact presence in the composite signal, such that when the ratio of the slopes meets or exceeds the threshold value, the external device 136 determines that the recharge parameters are insufficient to minimize noise in the recorded neurological signals. In some cases, the processor 144 may examine additional or alternative features of artifact curves (e.g., area under the curve, points of inflection, ratios and combinations thereof, and / or the like) and compare such features to other threshold values. Additionally or alternatively, the processor 144 may determine a SNR ratio of the composite signaland compare the SNR ratio to a threshold value, which may be a predetermined threshold value (e.g., a value stored in the database 130). When the SNR ratio falls below the threshold value, the external device 136 may determine that the recharge parameters are insufficient.

[0129] When the artifacts have been sufficiently minimized, the method 900 may optionally proceed to the step 804 of the method 800. In this case, the recharge parameters used in the method 900 may be used in the method 800 to generate a neurological response that has sufficient minimization of artifacts. In some embodiments, the external device 136 may determine if the hardware of the IMD 112 (e.g., the pulse generator 132, the leads 116A, 116B, the electrodes 124, etc.) is capable of generating pulses with the optimized recharge parameters. When the hardware of the IMD 112 is capable of generating pulses with the optimized recharge parameters, the external device 136 may set the recharge parameters as the default setting for the IMD 112. In cases where the hardware of the IMD 112 is not able to generate pulses with the optimized recharge parameters, the external device 136 may set the IMD 112 to generate electrical pulses with recharge parameters as close to the optimized recharge parameters as permitted by the hardware of the IMD 112.

[0130] The method 900 also comprises adjusting the recharge parameters (step 928). When the artifact has not been sufficiently minimized, the external device 136 may adjust one or more recharge parameters of the electrical pulses. The external device 136 may use one or more numerical optimization methods (e.g., gradient descent, stochastic gradient descent, Newton’s method, etc.) to adjust the recharge parameters such that the artifacts proceed toward similar amplitudes with opposite signs (e.g., in a direction that maximizes destructive interference between the artifact signals, in a direction that increases the SNR, etc.).

[0131] In some cases, the method 900 may repeat until the recharge parameters are optimized. The recharge parameters may be considered optimized after a predetermined or selected number of iterations (e.g., after 6 iterations, the recharge parameters used in the 6thiteration is selected as being optimized), the parameters that resulted in the least amount of noise / best artifact cancellation (e.g., the recharge parameters are optimized 6 times, and the 4thiteration produces the lowest amount of noise / highest SNR, so the recharge parameters associated with the 4thiteration are used), and / or the like. Any one or more other criteria may be used to determine that the recharge parameters are optimized.

[0132] The present disclosure encompasses embodiments of the method 900 that comprise more or fewer steps than those described above, and / or one or more steps that are different than the steps described above.

[0133] As noted above, the present disclosure encompasses methods with fewer than all of the steps identified in Figs. 8 and 9 (and the corresponding description of the methods 800 and 900), as well as methods that include additional steps beyond those identified in Figs. 8 and 9 (and the corresponding description of the methods 800 and 900). The present disclosure also encompasses methods that comprise one or more steps from one method described herein, and one or more steps from another method described herein. Any correlation described herein may be or comprise a registration or any other correlation.

[0134] The foregoing is not intended to limit the disclosure to the form or forms disclosed herein. In the foregoing Detailed Description, for example, various features of the disclosure are grouped together in one or more aspects, embodiments, and / or configurations for the purpose of streamlining the disclosure. The features of the aspects, embodiments, and / or configurations of the disclosure may be combined in alternate aspects, embodiments, and / or configurations other than those discussed above. This method of disclosure is not to be interpreted as reflecting an intention that the claims require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed aspect, embodiment, and / or configuration. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the disclosure.

[0135] Moreover, though the foregoing has included description of one or more aspects, embodiments, and / or configurations and certain variations and modifications, other variations, combinations, and modifications are within the scope of the disclosure, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative aspects, embodiments, and / or configurations to the extent permitted, including alternate, interchangeable and / or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and / or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.

[0136] A set of example statements are provided below:

[0137] Statement 1 : A method, comprising: generating, at a first time, a first electrical pulse;

[0138] measuring a first neurological response to the first electrical pulse; generating, at a second time, a second electrical pulse with at least one characteristic different than the first electrical pulse;

[0139] measuring a second neurological response to the second electrical pulse; and removing at least one artifact from at least one of the first neurological response and the second neurological response.

[0140] Statement 2: The method of Statement 1, wherein at least one of the first neurological response and the second neurological response comprises an Evoked Compound Action Potential (ECAP) response or Compound Muscle Action Potential (CMAP) response.

[0141] Statement 3: The method of any of Statements 1-2, wherein the at least one characteristic comprises an amount of time before a passive recharge phase that occurs after the second electrical pulse is paused to allow the measuring of the second neurological response.

[0142] Statement 4: The method of any of Statements 1-3, wherein the at least one characteristic comprises a recharge mechanism.

[0143] Statement 5: The method of any of Statements 1-4, wherein the first electrical pulse comprises an active recharge mechanism, and wherein the second electrical pulse comprises a passive recharge mechanism.

[0144] Statement 6: The method of any of Statements 1-5, wherein the first electrical pulse comprises a passive recharge mechanism, and wherein the second electrical pulse comprises an active recharge mechanism.

[0145] Statement 7: The method of any of Statements 1-6, wherein the at least one characteristic comprises at least one of an amplitude and a pulse width of a recharge phase of the second electrical pulse.

[0146] Statement 8: The method of any of Statements 1-7, wherein the at least one characteristic comprises an amplitude of a recharge phase, and wherein an amplitude of a recharge phase of the first electrical pulse is greater than an amplitude of a recharge phase the second electrical pulse.

[0147] Statement 9: The method of any of Statements 1-8, wherein the at least one characteristic comprises a pulse width of a recharge phase, and wherein a pulse width of a recharge phase of the first electrical pulse is less than a pulse width of a recharge phase the second electrical pulse.

[0148] Statement 10: The method of any of Statements 1-9, wherein the removing the at least one artifact further comprises: combining the first neurological response and the second neurological response into a composite response.

[0149] Statement 11 : The method of any of Statements 1-10, wherein the combining the first neurological response and the second neurological response comprises weighting at least one of the first neurological response and the second neurological response.

[0150] Statement 12: The method of any of Statements 1-11, wherein the composite response has reduced noise compared to the first neurological response and the second neurological response.

[0151] Statement 13: The method of any of Statements 1-12, wherein the first neurological response and the second neurological response are generated by an anatomical element, and wherein the method further comprises: selecting at least one recharge parameter that increases a signal to noise ratio of the composite response.

[0152] Statement 14: A device, comprising: a pulse generator configured to generate electrical pulses delivered to an anatomical element via a stimulation electrode; a processor; and a memory coupled with the processor and storing data thereon that, when processed by the processor, enable the processor to: cause the pulse generator to generate a first electrical pulse; receive a first neurological response of the anatomical element to the first electrical pulse; cause the pulse generator to generate a second electrical pulse with at least one characteristic different from the first electrical pulse; receive a second neurological response from the anatomical element to the second electrical pulse; and combine the first neurological response and the second neurological response into a composite response signal, wherein the composite response signal has less noise than the first neurological response and the second neurological response.

[0153] Statement 15: The device of Statement 14, wherein at least one of the first neurological response and the second neurological response comprises an Evoked Compound Action Potential (ECAP) response or a Compound Muscle Action Potential (CMAP) of the anatomical element.

[0154] Statement 16: The device of any of Statements 14-15, wherein the at least one characteristic comprises an amount of time before a passive recharge phase that occurs after the second electrical pulse is paused to allow measuring of the second neurological response.

[0155] Statement 17: The device of any of Statements 14-16, wherein the at least one characteristic comprises a recharge mechanism.

[0156] Statement 18: The device of any of Statements 14-17, wherein the first electrical pulse comprises an active recharge mechanism, and wherein the second electrical pulse comprises a passive recharge mechanism.

[0157] Statement 19: The device of any of Statements 14-18, wherein the first electrical pulse comprises a passive recharge mechanism, and wherein the second electrical pulse comprises an active recharge mechanism.

[0158] Statement 20: The device of any of Statements 14-19, wherein the at least one characteristic comprises at least one of an amplitude and a pulse width of a recharge phase of the second electrical pulse.

[0159] Statement 21: The device of any of Statements 14-20, the at least one characteristic comprises an amplitude of a recharge phase, and wherein an amplitude of a recharge phase of the first electrical pulse is greater than an amplitude of a recharge phase the second electrical pulse.

[0160] Statement 22: The device of any of Statements 14-21, wherein the at least one characteristic comprises a pulse width of a recharge phase, and wherein a pulse width of a recharge phase of the first electrical pulse is less than a pulse width of a recharge phase the second electrical pulse.

[0161] Statement 23: The device of any of Statements 14-22, wherein the combining of the first neurological response and the second neurological response comprises weighting at least one of the first neurological response and the second neurological response.

[0162] Statement 24: The device of any of Statements 14-23, wherein the data, when processed by the processor, further enable the processor to: select at least one recharge parameter that increases a signal to noise ratio of the composite response signal; cause the pulse generator to generate a third electrical pulse in accordance with the at least one recharge parameter; receive a third neurological response of the anatomical element to the third electrical pulse; and combine at least one of the first neurological response and the second neurological response with the third neurological response.

[0163] Statement 25: A device, comprising: a pulse generator that generates electrical pulses; a stimulation electrode electrically coupled with the pulse generator that delivers the electrical pulses generated by the pulse generator to an anatomical element; a processor; and a memory coupled with the processor and storing data thereon that, when processed by the processor, enable the processor to: receive a first neurological signal from the anatomical element in response to a first electrical pulse generated by the pulse generator and delivered by the stimulation electrode; receive a second neurological signal from the anatomical element in response to a second electrical pulse generated by the pulse generator and delivered by the stimulation electrode, wherein at least one characteristic of the second electrical pulse is different from the first electrical pulse; and combine the first neurological signal with the second neurological signal into a composite signal, wherein the composite signal has less noise than the first neurological signal and the second neurological signal.

[0164] Statement 26: The device of Statement 25, wherein at least one of the first neurological signal and the second neurological signal comprises an Evoked Compound Action Potential (ECAP) response or a Compound Muscle Action Potential (CMAP).

[0165] Statement 27: The device of any of Statements 25-26, wherein the at least one characteristic comprises an amount of time before a passive recharge phase that occurs after the second electrical pulse is paused to allow measuring of the second neurological signal.

[0166] Statement 28: The device of any of Statements 25-27, wherein the at least one characteristic comprises a recharge mechanism.

[0167] Statement 29: The device of any of Statements 25-28, wherein the first electrical pulse comprises an active recharge mechanism, and wherein the second electrical pulse comprises a passive recharge mechanism.

[0168] Statement 30: The device of any of Statements 25-29, wherein the first electrical pulse comprises a passive recharge mechanism, and wherein the second electrical pulse comprises an active recharge mechanism.

[0169] Statement 31: The device of any of Statements 25-30, wherein the at least one characteristic comprises at least one of an amplitude and a pulse width of a recharge phase of the second electrical pulse.

[0170] Statement 32: The device of any of Statements 25-31, wherein combining the first neurological signal and the second neurological signal comprises weighting at least one of the first neurological signal and the second neurological signal.

Claims

CLAIMSWhat is claimed is:

1. A method, comprising: generating, at a first time, a first electrical pulse; measuring a first neurological response to the first electrical pulse; generating, at a second time, a second electrical pulse with at least one characteristic different than the first electrical pulse; measuring a second neurological response to the second electrical pulse; and removing at least one artifact from at least one of the first neurological response and the second neurological response.

2. The method of claim 1, wherein at least one of the first neurological response and the second neurological response comprises an Evoked Compound Action Potential (ECAP) response or Compound Muscle Action Potential (CMAP) response.

3. The method of claim 1, wherein the at least one characteristic comprises an amount of time before a passive recharge phase that occurs after the second electrical pulse is paused to allow the measuring of the second neurological response.

4. The method of claim 1, wherein the at least one characteristic comprises a recharge mechanism.

5. The method of claim 4, wherein the first electrical pulse comprises an active recharge mechanism, and wherein the second electrical pulse comprises a passive recharge mechanism.

6. The method of claim 4, wherein the first electrical pulse comprises a passive recharge mechanism, and wherein the second electrical pulse comprises an active recharge mechanism.

7. The method of claim 1, wherein the at least one characteristic comprises at least one of an amplitude and a pulse width of a recharge phase of the second electrical pulse.

8. The method of claim 1, wherein the at least one characteristic comprises an amplitude of a recharge phase, and wherein an amplitude of a recharge phase of the first electrical pulse is greater than an amplitude of a recharge phase the second electrical pulse.

9. The method of claim 1, wherein the at least one characteristic comprises a pulse width of a recharge phase, and wherein a pulse width of a recharge phase of the first electrical pulse is less than a pulse width of a recharge phase the second electrical pulse.

10. The method of claim 1, wherein the removing the at least one artifact further comprises: combining the first neurological response and the second neurological response into a composite response.

11. The method of claim 10, wherein the combining the first neurological response and the second neurological response comprises weighting at least one of the first neurological response and the second neurological response.

12. The method of claim 10, wherein the composite response has reduced noise compared to the first neurological response and the second neurological response.

13. The method of claim 10, wherein the first neurological response and the second neurological response are generated by an anatomical element, and wherein the method further comprises: selecting at least one recharge parameter that increases a signal to noise ratio of the composite response.

14. A device, comprising: a pulse generator configured to generate electrical pulses delivered to an anatomical element via a stimulation electrode; a processor; and a memory coupled with the processor and storing data thereon that, when processed by the processor, enable the processor to: cause the pulse generator to generate a first electrical pulse;receive a first neurological response of the anatomical element to the first electrical pulse; cause the pulse generator to generate a second electrical pulse with at least one characteristic different from the first electrical pulse; receive a second neurological response from the anatomical element to the second electrical pulse; and combine the first neurological response and the second neurological response into a composite response signal, wherein the composite response signal has less noise than the first neurological response and the second neurological response.

15. A device, comprising: a pulse generator that generates electrical pulses; a stimulation electrode electrically coupled with the pulse generator that delivers the electrical pulses generated by the pulse generator to an anatomical element; a processor; and a memory coupled with the processor and storing data thereon that, when processed by the processor, enable the processor to: receive a first neurological signal from the anatomical element in response to a first electrical pulse generated by the pulse generator and delivered by the stimulation electrode; receive a second neurological signal from the anatomical element in response to a second electrical pulse generated by the pulse generator and delivered by the stimulation electrode, wherein at least one characteristic of the second electrical pulse is different from the first electrical pulse; and combine the first neurological signal with the second neurological signal into a composite signal, wherein the composite signal has less noise than the first neurological signal and the second neurological signal.

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