System for selecting neuromodulation parameters using electromyography

Abstract

A system for delivering neural stimulation energy is disclosed, comprising a stimulation control circuit for controlling the delivery of neural stimulation energy according to each of the stimulation test modes. The stimulation control circuit may include: a sensing input configured to receive an electromyelogram (ESG) signal that records electrical activity from the spinal cord; a measurement circuit configured to determine one or more response parameters of each test mode using the received ESG signal; and a selection circuit configured to select a neural stimulation treatment mode from the stimulation test mode based on (multiple) response parameters and one or more selection criteria. The electrical activity includes a response to the delivered neural stimulation energy, and the (multiple) response parameters each indicate one or more characteristics of the response. The selection may include selecting a type of stimulation waveform from a plurality of types of stimulation waveforms in the stimulation test mode.

Description

[0001] Priority claim

[0002] This application claims the benefit of priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Serial No. 62 / 829,186, filed on April 4, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This document relates generally to neuromodulation and, more particularly, to a method and system for automatically selecting stimulation parameters for neuromodulation using electromyography (ESG). Background Art

[0004] Neurostimulation (also known as neuromodulation) has been proposed as a treatment for many diseases. Examples of neurostimulation include spinal cord stimulation (SCS), deep brain stimulation (DBS), peripheral nerve stimulation (PNS) and functional electrical stimulation (FES). Implantable neurostimulation systems have been applied to deliver this treatment. An implantable neurostimulation system may include an implantable neurostimulator (which may also be referred to as an implantable pulse generator (IPG)) and one or more implantable leads each including one or more electrodes. The implantable neurostimulator delivers neurostimulation energy through one or more electrodes placed on or near a target site in the nervous system. An external programming device is used to program the implantable neurostimulator using stimulation parameters that control the delivery of neurostimulation energy.

[0005] In one example, neurostimulation energy is delivered in the form of electrical pulses. Delivery is controlled using stimulation parameters that specify the spatial (where to stimulate), temporal (when to stimulate), and informational (pulse patterns that guide the nervous system to respond in accordance with a desired response) aspects of the pattern of electrical pulses. By determining these stimulation parameters based on the patient's condition and treatment goals, the efficacy and efficiency of certain neurostimulation treatments can be improved, and their side effects can be reduced. While modern electronic devices can accommodate the needs for generating complex pulse patterns, the capability of a neurostimulation system depends on how the stimulation parameters that define such pulse patterns are determined and adjusted for the patient to ensure the efficacy and efficiency of the treatment using neurostimulation when applied to the patient. Summary of the invention

[0006] An example of a system for delivering neural stimulation energy to a patient having a spinal cord via multiple electrodes (e.g., "Example 1") may include a stimulation control circuit that may be configured to control the delivery of neural stimulation energy according to each of a plurality of neural stimulation test modes. The stimulation control circuit may include a sensing input, a measurement circuit, and a selection circuit. The sensing input may be configured to receive an electromyelogram (ESG) signal that records electrical activity from the spinal cord. The electrical activity includes a response to the delivered neural stimulation energy. The measurement circuit may be configured to use the received ESG signal to determine one or more response parameters for each of a plurality of neural stimulation test modes. The one or more response parameters each indicate one or more characteristics of a response to the delivered neural stimulation energy. The selection circuit may be configured to select a neural stimulation treatment mode from a plurality of stimulation test modes based on the one or more response parameters and one or more selection criteria. The selection may include selecting a type of stimulation waveform from a plurality of types of stimulation waveforms in a plurality of stimulation test modes.

[0007] In Example 2, the subject matter of Example 1 can optionally be configured such that the selection circuit is configured to select the neural stimulation therapy mode from the plurality of stimulation test modes periodically or in response to a need for a selection update being identified.

[0008] In Example 3, the subject matter of any one or any combination of Examples 1 and 2 can optionally be configured such that the measurement circuit is configured to determine one or more neural response parameters of the one or more response parameters, and the selection circuit is configured to select the neural stimulation treatment mode from the plurality of stimulation test modes based on the one or more neural response parameters and the one or more selection criteria. The one or more neural response parameters each indicate one or more characteristics of an induced response, the induced responses each being a neural response induced by the delivered neural stimulation energy,

[0009] In Example 4, the subject matter of any one or any combination of Examples 1 to 3 can optionally be configured such that the neural stimulation test modes are each defined by one or more waveforms, the one or more waveforms each specifying a temporal pattern of neural modulation energy comprising that type of stimulation waveform, and the multiple types of stimulation waveforms include an active recharge waveform.

[0010] In Example 5, the subject matter of any one or any combination of Examples 1 to 4 can optionally be configured such that the neural stimulation patterns are each defined by one or more fields, the one or more fields each specifying a spatial distribution of neural stimulation energy across the plurality of electrodes.

[0011] In Example 6, the subject matter of any one or any combination of Examples 3 to 5 can optionally be configured such that the measurement circuit is further configured to determine values ​​of one or more neural response parameters that each correspond to a test mode in a plurality of neural stimulation test modes, and the selection circuit is further configured to select a neural stimulation therapy mode by selecting a test mode corresponding to a value in the determined values ​​identified according to one or more selection criteria.

[0012] In Example 7, the subject matter of Example 6 can optionally be configured such that the selection circuit is configured to select the neural stimulation therapy mode by selecting a test pattern corresponding to a maximum induced response identified from among induced responses corresponding to a plurality of neural stimulation test patterns.

[0013] In Example 8, the subject matter of Example 7 can optionally be configured such that the measurement circuit is further configured to determine an area under a curve for the one or more neural response parameters. The area under a curve is the area between the ESG signal and the baseline over a specified time interval.

[0014] In Example 9, the subject matter of Example 7 can optionally be configured such that the measurement circuit is further configured to determine a curve length of the one or more neural response parameters. The curve length is the duration of the evoked response within a specified time interval.

[0015] In Example 10, the subject matter of Example 7 can optionally be configured such that the measurement circuit is further configured to determine a peak-to-peak amplitude of the one or more neural response parameters. The peak-to-peak amplitude is the difference between the amplitudes of two peaks of a specified type in the ESG signal.

[0016] In Example 11, the subject matter of Example 7 can optionally be configured such that the measurement circuit is further configured to generate a derivative of the received ESG signal, and is further configured to determine one or more additional neural response parameters using the generated derivative of the received ESG signal. The one or more additional neural response parameters each indicate one or more additional characteristics of the induced response.

[0017] In Example 12, the subject matter of any one or any combination of Examples 6 to 11 can optionally be configured such that the selection circuit is configured to select a neurostimulation therapy mode by selecting a test pattern corresponding to a maximum pain-paresthesia overlap identified from induced responses corresponding to multiple neurostimulation test patterns.

[0018] In Example 13, the subject matter of Example 12 can optionally be configured such that the selection circuit is configured to compare the received ESG signal with a previously recorded ESG signal to identify a test pattern based on similarity to a portion of the previously recorded ESG signal corresponding to a maximum pain-paresthesia overlap.

[0019] In Example 14, the subject matter of any one or any combination of Examples 1 to 13 can optionally be configured such that the stimulation control circuit is also configured to control the delivery of neural stimulation energy according to the selected neural stimulation therapy mode, and also includes an adjustment circuit configured to adjust one or more stimulation parameters of the selected neural stimulation therapy mode based on one or more neural response parameters measured after the delivery of neural stimulation energy according to the neural stimulation therapy mode has begun.

[0020] In Example 15, the subject matter of Example 14 can optionally be configured such that the adjustment circuit is further configured to adjust one or more stimulation parameters of the selected neural stimulation therapy mode so that the value of each of the adjusted one or more stimulation parameters remains within a specified range.

[0021] Also provided is an example of a method for delivering neural stimulation energy to a patient having a spinal cord via multiple electrodes (e.g., "Example 16"). The method may include: controlling the delivery of neural stimulation energy according to each of a plurality of neural stimulation test modes; receiving an electromyelogram (ESG) as a record of electrical activity from the spinal cord; determining one or more response parameters for each of a plurality of neural stimulation test modes using the received ESG signal; and selecting a neural stimulation treatment mode from a plurality of stimulation test modes based on the one or more response parameters and one or more selection criteria. The electrical activity includes a response to the delivered neural stimulation energy. The one or more response parameters each indicate one or more characteristics of a response to the delivered neural stimulation energy. The selection may include selecting a type of stimulation waveform from a plurality of types of stimulation waveforms in the plurality of stimulation test modes.

[0022] In Example 17, the subject matter of determining one or more response parameters as found in Example 16 may optionally include determining one or more neural response parameters, each of which indicates one or more characteristics of an induced response, each of the induced responses being a neural response induced by the delivered neural stimulation energy, and the subject matter of selecting a neural stimulation treatment mode as found in Example 16 may optionally include selecting a neural stimulation treatment mode from a plurality of stimulation test modes based on the one or more neural response parameters and one or more selection criteria.

[0023] In Example 18, the subject matter of selecting a neurostimulation therapy mode as found in any one or any combination of Examples 16 and 17 can optionally include selecting a waveform specifying a temporal pattern of neuromodulatory energy comprising that type of stimulation waveform, and the plurality of types of stimulation waveforms include an active recharge waveform.

[0024] In Example 19, the subject matter of selecting a neural stimulation treatment mode as found in any one or any combination of Examples 16 to 18 can optionally include selecting a field specifying a spatial distribution of neural stimulation energy across a plurality of electrodes.

[0025] In Example 20, the subject matter of determining one or more neural response parameters as found in any one or any combination of Examples 17 to 19 may optionally include determining values ​​of the one or more neural response parameters that each correspond to a test mode in a plurality of neural stimulation test modes, and the subject matter of selecting a neural stimulation treatment mode as found in any one or any combination of Examples 17 to 19 may optionally include selecting a test mode that corresponds to a value among the determined values ​​that indicates a maximum induced response among the induced responses corresponding to the plurality of neural stimulation test modes.

[0026] In Example 21, the subject matter of determining one or more neural response parameters as found in any one or any combination of Examples 17 to 20 can optionally include determining a curve area as the area between the ESG signal and a baseline over a specified time interval, a curve length as the duration of the induced response over a specified time interval, a peak-to-peak amplitude as the difference between the amplitudes of two specified types of peaks in the ESG signal, or at least one of the one or more neural response parameters measured from a derivative of the received ESG signal.

[0027] In Example 22, the subject matter of selecting a neurostimulation treatment mode as found in any one or any combination of Examples 17 to 21 can optionally include selecting a test mode corresponding to a maximum pain-paresthesia overlap identified from evoked responses corresponding to multiple neurostimulation test modes.

[0028] In Example 23, the subject matter of any one or any combination of Examples 17 to 22 may optionally include controlling the delivery of neural stimulation energy according to a selected neural stimulation therapy mode, and adjusting one or more stimulation parameters of the selected neural stimulation therapy mode based on one or more neural response parameters measured after the delivery of neural stimulation energy according to the neural stimulation therapy mode has begun, so that the value of each of the adjusted one or more stimulation parameters remains within a specified range during the delivery of neural stimulation energy according to the neural stimulation therapy mode.

[0029] Also provided is an example of a non-transitory computer-readable storage medium including instructions (e.g., "Example 24") that, when executed by a system, causes the system to perform a method for delivering neural stimulation energy to a patient having a spinal cord through multiple electrodes. The method may include: controlling the delivery of neural stimulation energy according to each of a plurality of neural stimulation test modes; receiving an electromyelogram (ESG) as a record of electrical activity from the spinal cord; determining one or more response parameters for each of a plurality of neural stimulation test modes using the received ESG signal; and selecting a neural stimulation treatment mode from a plurality of stimulation test modes based on the one or more response parameters and one or more selection criteria. The electrical activity includes a response to the delivered neural stimulation energy. The one or more response parameters each indicate one or more characteristics of a response to the delivered neural stimulation energy. The selection may include selecting a type of stimulation waveform from a plurality of types of stimulation waveforms in the plurality of stimulation test modes.

[0030] In Example 25, the subject matter of Example 24 can optionally be configured such that determining one or more response parameters includes determining one or more neural response parameters, each of which indicates one or more characteristics of an induced response, each of the induced responses being a neural response induced by the delivered neural stimulation energy, and selecting a neural stimulation therapy mode includes selecting a neural stimulation therapy mode from a plurality of stimulation test modes based on the one or more neural response parameters and one or more selection criteria.

[0031] This summary is an overview of some of the teachings of the present application and is not intended to be an exclusive or exhaustive treatment of the subject matter. More details about this subject matter can be found in the detailed description and the appended claims. Other aspects of the present disclosure will be apparent to those skilled in the art upon reading and understanding the following detailed description and viewing the accompanying drawings that form a part thereof (each of which is not viewed in a limiting sense). The scope of the present disclosure is limited by the appended claims and their legal equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings generally illustrate various embodiments discussed in this document by way of example. The drawings are for illustration purposes only and may not be drawn to scale.

[0033] Figure 1 An embodiment of a neural stimulation system is shown.

[0034] Figure 2 It shows that Figure 1 Embodiments of a stimulation device and a lead system implemented in a neural stimulation system.

[0035] Figure 3 It shows that Figure 1An embodiment of a programming device implemented in a neural stimulation system.

[0036] Figure 4 An implantable pulse generator (IPG) and an implantable lead system (such as Figure 2 An embodiment of an example implementation of a stimulation device and a lead system).

[0037] Figure 5 An IPG and implantable lead system (such as Figure 4 An embodiment of an IPG and lead system).

[0038] Figure 6 Embodiments of portions of a neural stimulation system are shown.

[0039] Figure 7 An implantable stimulator and a Figure 6 Embodiments of one or more leads of an implantable neurostimulation system.

[0040] Figure 8 Shows such as Figure 6 Embodiments of an implantable neurostimulation system and an external programming device for an implantable neurostimulation system.

[0041] Fig. 9 An embodiment of a stimulation control circuit for selecting a neural stimulation mode using electromyography (ESG) is shown.

[0042] Fig.10 is a graph showing an example of a neural response seen on an ESG induced by a neural stimulation pulse.

[0043] Fig.11 Embodiments of systems for delivering neural stimulation including stimulation control circuitry for selecting a neural stimulation mode using ESG are shown.

[0044] FIG. 12A to FIG. 12I Each shows an example of a stimulation waveform.

[0045] Fig.13 An embodiment of a display screen area that allows a user to select a neural stimulation mode using ESG is shown.

[0046] Fig.14 Embodiments of methods for delivering neural stimulation, including using ESG to select a neural stimulation mode, are presented. DETAILED DESCRIPTION

[0047] In the following detailed description, reference is made to the accompanying drawings, which form a part of the description and in which specific embodiments in which the invention may be practiced are shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that these embodiments may be combined, or other embodiments may be utilized, and that structural, logical, and electrical changes may be made without departing from the spirit and scope of the invention. References to "one," "one," or "various" embodiments in this disclosure do not necessarily refer to the same embodiment, and such references contemplate more than one embodiment. The following detailed description provides examples, and the scope of the invention is defined by the appended claims and their legal equivalents.

[0048] The document discusses, among other things, a neurostimulation system that can use information extracted from a patient's electromyogram (ESG) to control the delivery of neurostimulation to a patient. In various embodiments, a neuromodulation system can include an implantable device configured to deliver neurostimulation (also referred to as neuromodulation) therapy, such as deep brain stimulation (DBS), spinal cord stimulation (SCS), peripheral nerve stimulation (PNS), and vagus nerve stimulation (VNS), and one or more external devices configured to program the implantable device for operation of the implantable device and monitor the performance of the implantable device. Although the use of an implantable device to deliver SCS is discussed as a specific example, the present subject matter can also be applied to programmed stimulation devices for delivering various types of neuromodulation therapies.

[0049] The ESG is a record of electrical activity from the spinal cord. Many nerve cells produce low-level electrical signals called action potentials, which form patterns of electrical activity and can have a superposition effect of producing an amplified neural response in many cases. An example is an evoked compound action potential (ECAP), which is evoked by a stimulus such as a nerve stimulation pulse and is produced by the discharge of many nerve cells simultaneously or close in time. The ESG signal also includes a neural component that has a random appearance and represents the activity of many different types of cells in the patient's nervous system that discharge spontaneously over time. The ESG also includes non-neural components that represent various body movements of the patient, such as movements associated with cardiac activity, respiratory activity, and skeletal muscle activity.

[0050] ESG signals can be sensed non-invasively using surface electrodes attached to the patient's skin. Such surface sensing typically requires an amplifier with high gain and a high signal-to-noise ratio (SNR). ESG signals can also be sensed invasively using electrodes attached to one or more percutaneous or implantable leads. In one example, ESG signals are sensed extradurally using epidural electrodes placed adjacent to or above the dura mater, which is a membrane structure surrounding the patient's spinal cord and cerebral cortex. In another example, ESG signals are sensed intradurally using leads that penetrate the dura mater so that electrodes can be placed in the spinal cord below the dura mater.

[0051] Findings from recent clinical studies indicate that fast-acting pain relief can be achieved by using SCS with an active recharge waveform with an intensity just below the threshold for spinal activation-induced paresthesia. ESG signals can be sensed from the patient to indicate the characteristics (e.g., amplitude and shape) of the patient's spinal response to stimulation, and can therefore be used to evaluate stimulation parameters (e.g., waveform and tissue site of stimulation) to select an appropriate stimulation mode. It has been observed that the neural responses induced by SCS with an active recharge waveform exhibit increased amplitude and changing shape, respectively, as the stimulation increases and changes with stimulation amplitude, stimulation pulse width, and / or proximity of the stimulation site to the spinal cord. Spinal fibers of different diameters are known to produce neural responses after different delays, with fibers of smaller diameters associated with larger delays. The ECAPs detectable from the ESG are the result of the superposition effect of multiple action potentials generated by different axons of different diameters firing with different delays. The present system can use the ECAPs appearing in the ESG to indicate the desired response to neural stimulation and evaluate various neural stimulation modes in order to select a mode suitable for the patient to control the delivery of treatment to the patient. In this document, a "patient" includes a person receiving therapy delivered using a neurostimulation system according to the present subject matter, and a "user" includes a physician or other caregiver who uses the neurostimulation system to treat the patient.

[0052] Figure 1An embodiment of a neurostimulation system 100 is shown. The system 100 includes an electrode 106, a stimulation device 104, and a programming device 102. The electrode 106 is configured to be placed on or near one or more neural targets in a patient's body. The stimulation device 104 is configured to be electrically connected to the electrode 106 and deliver neural stimulation energy, such as in the form of electrical pulses, to one or more neural targets through the electrode 106. The delivery of neural stimulation is controlled by using multiple stimulation parameters (such as stimulation parameters that specify an electrical pulse pattern) and electrode selection through which each of the electrical pulses is delivered. In various embodiments, at least some of the multiple stimulation parameters are programmable by a user (such as a physician or other caregiver treating a patient using the system 100). The programming device 102 provides the user with access to user-programmable parameters. In various embodiments, the programming device 102 is configured to be communicatively coupled to the stimulation device via a wired or wireless link.

[0053] In various embodiments, programming device 102 may include user interface 110 that allows a user to control the operation of system 100 and monitor the performance of system 100 and the patient's condition, including the response to the delivery of neural stimulation. The user may control the operation of system 100 by setting and / or adjusting the values ​​of user-programmable parameters.

[0054] In various embodiments, the user interface 110 may include a graphical user interface (GUI) that allows a user to set and / or adjust the values ​​of user-programmable parameters by creating and / or editing graphical representations of various waveforms. Such waveforms may include, for example, waveforms representing a neural stimulation pulse pattern to be delivered to a patient, and individual waveforms used as building blocks of the neural stimulation pulse pattern, such as the waveform of each pulse in the neural stimulation pulse pattern. The GUI may also allow a user to set and / or adjust stimulation fields, each defined by a set of free electrodes, through which one or more neural stimulation pulses represented by the waveform are delivered to the patient. Each stimulation field may also be defined by the distribution of current for each neural stimulation pulse in the waveform. In various embodiments, neural stimulation pulses within a stimulation period (such as the duration of a treatment session) may be delivered to multiple stimulation fields.

[0055] In various embodiments, the system 100 can be configured for neurostimulation applications. The user interface 110 can be configured to allow a user to control the operation of the system 100 for neurostimulation. For example, the system 100 and the user interface 110 can be configured for SCS applications. Such an SCS configuration includes various features that can simplify the user's task in programming the stimulation device 104 for delivering SCS to a patient, such as the features discussed in this document.

[0056] Figure 2An embodiment of a stimulation device 204 and a lead system 208 (such as may be implemented in the neural stimulation system 100) is shown. The stimulation device 204 represents an example of the stimulation device 104 and includes a stimulation output circuit 212 and a stimulation control circuit 214. The stimulation output circuit 212 generates and delivers neural stimulation pulses. The stimulation control circuit 214 uses a plurality of stimulation parameters to control the delivery of neural stimulation pulses from the stimulation output circuit 212, which specifies the pattern of the neural stimulation pulses. The lead system 208 may include one or more leads each configured to be electrically connected to the stimulation device 204 and a plurality of electrodes 206 distributed in the one or more leads. The plurality of electrodes 206 may include an electrode 206-1, an electrode 206-2, ..., an electrode 206-N, each of which is a single conductive contact providing an electrical interface between the stimulation output circuit 212 and the patient's tissue, where N≥2. The neural stimulation pulses are each delivered from the stimulation output circuit 212 through a set of electrodes selected from the electrodes 206. In various embodiments, the neural stimulation pulses may include one or more individually defined pulses, and the electrode set may be individually defined by the user for each of the individually defined pulses or for each of the pulse sets intended to be delivered using the same electrode combination. In various embodiments, one or more additional electrodes 207 (each of which may be referred to as a reference electrode) may be electrically connected to the stimulation device 204, such as one or more electrodes that are each part of the stimulation device 204 or otherwise incorporated into its housing. Monopolar stimulation uses a monopolar electrode configuration in which one or more electrodes are selected from the electrodes 206 and at least one electrode is selected from the electrode(s) 207. Bipolar stimulation uses a bipolar electrode configuration in which two electrodes are selected from the electrodes 206 and there is no electrode(s) 207. Multipolar stimulation uses a multipolar electrode configuration in which multiple (two or more) electrodes are selected from the electrodes 206 and there is no electrode(s) 207.

[0057] In various embodiments, the number of leads and the number of electrodes on each lead depends on, for example, the distribution of the target(s) for neural stimulation and the need to control the electric field distribution at each target. In one embodiment, lead system 208 includes 2 leads each having 8 electrodes.

[0058] Figure 3An embodiment of a programming device 302 such as may be implemented in a neurostimulation system 100 is shown. The programming device 302 represents an example of the programming device 102 and includes a storage device 318, a programming control circuit 316, and a user interface 310. The programming control circuit 316 generates a plurality of stimulation parameters that control the delivery of neurostimulation pulses according to a specified neurostimulation program, which may define, for example, stimulation waveforms and electrode configurations. The user interface 310 represents an example of the user interface 110 and includes a stimulation control circuit 320. The storage device 318 stores information used by the programming control circuit 316 and the stimulation control circuit 320, such as information about a stimulation device that relates a neurostimulation program to a plurality of stimulation parameters. In various embodiments, the stimulation control circuit 320 may be configured to support one or more functions that allow a stimulation device (such as the stimulation device 104 including various embodiments thereof discussed in this document) to be programmed according to one or more selected neurostimulation programs discussed in this document.

[0059] In various embodiments, the user interface 310 may allow for defining a pattern of neural stimulation pulses for delivery during a neural stimulation therapy session by creating and / or adjusting one or more stimulation waveforms using graphical methods. The definition may also include the definition of one or more stimulation fields, each associated with one or more pulses in the pattern of neural stimulation pulses. As used herein, a "neurostimulation program" may include a neural stimulation pulse pattern that includes one or more stimulation fields, or at least various aspects or parameters of a neural stimulation pulse pattern that includes one or more stimulation fields. In various embodiments, the user interface 310 includes a GUI that allows a user to define a pattern of neural stimulation pulses and perform other functions using graphical methods. In this document, "neurostimulation programming" may include the definition of one or more stimulation waveforms, including the definition of one or more stimulation fields.

[0060] In various embodiments, the circuitry of neural stimulation 100 (including the various embodiments thereof discussed herein) can be implemented using a combination of hardware and software. For example, the circuitry of user interface 110, stimulation control circuitry 214, programming control circuitry 316, and stimulation control circuitry 320 (including the various embodiments thereof discussed herein) can be implemented using dedicated circuitry configured to perform one or more specific functions or general purpose circuitry programmed to perform (multiple) such functions. Such general purpose circuitry includes, but is not limited to, a microprocessor or a portion thereof, a microcontroller or a portion thereof, and a programmable logic circuit or a portion thereof.

[0061] Figure 4An embodiment of an implantable pulse generator (IPG) 404 and an implantable lead system 408 are shown. IPG 404 represents an example implementation of stimulation device 204. Lead system 408 represents an example implementation of lead system 208. Figure 4 As shown, IPG 404 can be coupled to implantable leads 408A and 408B at the proximal end of each lead. The distal end of each lead includes an electrical contact or electrode 406 for contacting a tissue site that is the target of electrical nerve stimulation. Figure 1 As shown, leads 408A and 408B each include eight electrodes 406 at the distal end. Figure 1 The number and arrangement of leads 408A and 408B and electrodes 406 shown are examples only, and other numbers and arrangements are possible. In various embodiments, the electrodes are ring electrodes. The implantable leads and electrodes can be configured by shape and size to provide electrical neural stimulation energy to neuronal targets included in the subject's brain, or configured to provide electrical neural stimulation energy to neural cell targets included in the subject's spinal cord.

[0062] Figure 5 An implantable neural stimulation system 500 and a portion of an environment in which the system 500 may be used are shown. The system 500 includes an implantable system 521, an external system 502, and a telemetry link 540 that provides wireless communication between the implantable system 521 and the external system 502. Figure 5 is shown implanted within a patient's body 599.

[0063] The implantable system 521 includes an implantable stimulator (also referred to as an implantable pulse generator or IPG) 504, a lead system 508, and electrodes 506, which represent examples of the stimulation device 204, the lead system 208, and the electrodes 206, respectively. The external system 502 represents an example of the programming device 302. In various embodiments, the external system 502 includes one or more external (non-implantable) devices that each allow a user and / or a patient to communicate with the implantable system 521. In some embodiments, the external system 502 includes a programming device intended for a user to initialize and adjust settings for the implantable stimulator 504 and a remote control device for use by a patient. For example, the remote control device can allow a patient to turn the implantable stimulator 504 on and off and / or adjust certain patient-programmable parameters of a plurality of stimulation parameters.

[0064] The size and shape of the elements of the implantable system 521 and their location in the body 599 are shown as examples and not as limitations. According to various embodiments of the present subject matter, the implantable system is discussed as a specific application of programming. In various embodiments, the present subject matter can be applied to programming any type of stimulation device that uses electrical pulses as stimulation, regardless of the stimulation target within the patient's body and whether the stimulation device is implantable.

[0065] Back to Figure 4 , IPG 404 may include an airtightly sealed IPG housing 422 to house the electronic circuitry of IPG 404. IPG 404 may include an electrode 426 formed on IPG housing 422. IPG 404 may include an IPG head 424 for coupling the proximal ends of leads 408A and 408B. IPG head 424 may also optionally include electrode 428. Electrodes 426 and / or 428 represent embodiments of (multiple) electrodes 207 and may each be referred to as a reference electrode. Electrode 426 or electrode 428 and one or more electrodes selected from electrode 406 may be used to deliver neural stimulation energy in a monopolar (also referred to as unipolar) mode. Neural stimulation energy may be delivered in a bipolar mode using a pair of electrodes of the same lead (lead 408A or lead 408B). Neural stimulation energy may be delivered in an extended bipolar mode using one or more electrodes of a lead (eg, one or more electrodes of lead 408A) and one or more electrodes of a different lead (eg, one or more electrodes of lead 408B).

[0066] The electronic circuit system of IPG 404 may include control circuitry that controls the delivery of neural stimulation energy. The control circuitry may include a microprocessor, a digital signal processor, an application specific integrated circuit (ASIC), or other types of processors that interpret or execute instructions contained in software or firmware. The neural stimulation energy may be delivered according to specified (e.g., programmed) modulation parameters. Examples of setting modulation parameters may include, among others, selecting electrodes or electrode combinations used in stimulation, configuring one or more electrodes as anodes or cathodes for stimulation, specifying the percentage of neural stimulation provided by the electrodes or electrode combinations, and specifying stimulation pulse parameters. Examples of pulse parameters include, among others, the amplitude of the pulse (specified in current or voltage), the pulse duration (e.g., in microseconds), the pulse rate (e.g., expressed in pulses per second), and parameters associated with a pulse train or pattern (such as a pulse train rate (e.g., an "on" modulation time followed by an "off" modulation time), the amplitude of the pulses in the pulse train, the polarity of the pulses, etc.

[0067] Figure 6An embodiment of the various parts of a neurostimulation system 600 is shown. The system 600 includes an IPG 604, implantable neurostimulation leads 608A and 608B, an external remote controller (RC) 632, a clinician's programmer (CP) 630, and an external trial modulator (ETM) 634. The IPG 404 can be electrically coupled to the leads 608A and 608B directly or through a percutaneous extension lead 636. The ETM 634 can be electrically connected to the leads 608A and 608B via one or both of the percutaneous extension lead 636 and / or the external cable 638. System 600 represents an example of system 100 , where IPG 604 represents an embodiment of stimulation device 104 , electrodes 606 of leads 608A and 608B represent electrodes 106 , and CP 630 , RC 632 , and ETM 634 collectively represent programming device 102 .

[0068] The ETM 634 may be stand-alone or incorporated into the CP 630. The ETM 634 may have similar pulse generation circuitry as the IPG 604 to deliver neural stimulation energy according to specified modulation parameters as discussed above. The ETM 634 is an external device that is typically used as a preliminary stimulator after the leads 408A and 408B have been implanted and used, and is used to test the patient's responsiveness to stimulation provided by the IPG 604 before stimulating with the IPG 604. Because the ETM 634 is external, it may be easier to configure than the IPG 604.

[0069] CP 630 may configure the neural stimulation provided by ETM 634. If ETM 634 is not integrated into CP 630, CP 630 may communicate with ETM 634 using a wired connection (e.g., via a USB link) or via wireless telemetry using wireless communication link 640. CP 630 also communicates with IPG 604 using wireless communication link 640.

[0070] An example of wireless telemetry is based on inductive coupling between two closely placed coils, taking advantage of the mutual inductance between these coils. This type of telemetry is called inductive telemetry or near-field telemetry because the coils must generally be placed closely to obtain inductive coupling communication. The IPG 604 may include a first coil and a communication circuit. The CP 630 may include or otherwise be electrically connected to a second coil (such as in the form of a stick that may be placed near the IPG 604). Another example of wireless telemetry includes a far-field telemetry link, also known as a radio frequency (RF) telemetry link. The far field (also known as the Fraunhofer zone) refers to a zone in which the components of the electromagnetic field generated by a source of emitting electromagnetic radiation are substantially attenuated in proportion to 1 / r, where r is the distance between the observation point and the radiation source. Thus, the far field refers to the zone outside the boundary of r=λ / 2π, where λ is the wavelength of the electromagnetic energy transmitted. In one example, the communication range of the RF telemetry link is at least 6 feet, but may be as long as the particular communication technology allows. RF antennas may be included in, for example, the head of the IPG 604 and the housing of the CP 630, thereby eliminating the need for a wand or other means of inductive coupling. An example of such an RF telemetry link is a Bluetooth wireless link.

[0071] The CP 630 may be used to set the modulation parameters of the neural stimulation after the IPG 604 has been implanted. This allows the neural stimulation to be tuned if the requirements for the neural stimulation change after implantation. The CP 630 may also upload information from the IPG 604.

[0072] The RC 632 also communicates with the IPG 604 using the wireless link 340. The RC 632 can be a communication device used by a user or given to a patient. The RC 632 may have reduced programming capabilities compared to the CP 630. This allows the user or patient to change the neural stimulation treatment, but does not allow the patient to have full control over the treatment. For example, the patient may be able to increase the amplitude of the neural stimulation pulses or change the time for applying a preprogrammed stimulation pulse sequence. The RC 632 can be programmed by the CP 630. The CP 630 can communicate with the RC 632 using a wired or wireless communication link. In some embodiments, the CP 630 can program the RC 632 while being away from the RC 632.

[0073] Figure 7An embodiment of an implantable stimulator 704 and one or more leads 708 of an implantable neural stimulation system, such as implantable system 600, is shown. Implantable stimulator 704 represents an example of stimulation device 104 or 204 and can be implemented, for example, as IPG 604. Lead(s) 708 represent an example of lead system 208 and can be implemented, for example, as implantable leads 608A and 608B. Lead(s) 708 include electrode 706, which represents an example of electrode 106 or 206 and can be implemented as electrode 606.

[0074] The implantable stimulator 704 may include a sensing circuit 742 that provides sensing capabilities for the stimulator, a stimulation output circuit 212, a stimulation control circuit 714, an implant storage device 746, an implant telemetry circuit 744, a power supply 748, and one or more electrodes 707. The sensing circuit 742 may send one or more physiological signals for patient monitoring of neural stimulation and / or feedback control of neural stimulation. In various embodiments, the sensing circuit 742 may sense one or more ESG signals using electrodes placed above or below the spinal dura mater, such as electrodes 706 (which may include epidural and / or intradural electrodes). In addition to one or more ESG signals, examples of one or more physiological signals include neural signals and other signals that each indicate a condition of a patient treated by neural stimulation and / or a patient's response to the delivery of neural stimulation. The stimulation output circuit 212 is electrically connected to the electrode 706 via one or more leads 708 and the electrode 707, and delivers each of the neural stimulation pulses via an electrode set selected from the electrode 706 and (multiple) electrodes 707. Stimulation control circuit 714 represents an example of stimulation control circuit 214, and uses multiple stimulation parameters that specify the mode of neural stimulation pulses to control the delivery of neural stimulation pulses. In one embodiment, stimulation control circuit 714 uses one or more sensed physiological signals to control the delivery of neural stimulation pulses. Implant telemetry circuit 744 provides wireless communication with another device such as CP 630 and RC 632 for implantable stimulator 704, including receiving the value of multiple stimulation parameters from another device. Implant storage device 746 can store one or more neural stimulation programs and the value of multiple stimulation parameters for each of one or more neural stimulation programs. Power supply 748 provides energy for implantable stimulator 704 for its operation. In one embodiment, power supply 748 includes a battery. In one embodiment, power supply 748 includes a rechargeable battery and a battery charging circuit for charging the rechargeable battery. Implant telemetry circuit 744 can also act as a power receiver, which receives power transmitted from an external device through inductive coupling. (Multiple) electrodes 707 allow neural stimulation pulses to be delivered in a monopolar mode. Examples of electrode(s) 707 include electrode 426 and electrode 418 in IPG 404, such as Figure 4 shown.

[0075] In one embodiment, implantable stimulator 704 is used as a master database. Therefore, when this information is otherwise unavailable, a patient implanted with implantable stimulator 704 (such as can be implemented as IPG 604) can carry the patient information required for his or her medical care. Implant storage device 746 is configured to store such patient information. For example, a patient may be given a new RC 632 and / or go to a new clinic, where a new CP 630 is used to communicate with the device implanted in him or her. New RC 632 and / or CP 630 can communicate with implantable stimulator 704 to retrieve the patient information stored in implant storage device 746 through implant telemetry circuit 744 and wireless communication link 640, and allow any necessary adjustment to the operation of implantable stimulator 704 based on the retrieved patient information. In various embodiments, the patient information to be stored in the implant storage device 746 may include, for example, the position of the lead(s) 708 and electrodes 706 relative to the patient's anatomy (a transformation for fusing post-operative lead placement computed tomography (CT) images to magnetic resonance imaging (MRI) images of the brain), clinical effect map data, objective measurements using quantitative assessment of symptoms (e.g., using microelectrode recordings, accelerometers, and / or other sensors), and / or any other information deemed important or useful in providing adequate care to the patient. In various embodiments, the patient information to be stored in the implant storage device 746 may include data transmitted to the implantable stimulator 704 for storage as part of the patient information and data acquired by the implantable stimulator 704 (such as by using the sensing circuit 742).

[0076] In various embodiments, the sensing circuit 742 (if included), the stimulation output circuit 212, the stimulation control circuit 714, the implant telemetry circuit 744, the implant storage device 746, and the power source 748 are enclosed in a hermetically sealed implantable housing or shell, and the (multiple) electrodes 707 are formed or otherwise bonded to the shell. In various embodiments, the (multiple) lead 708 is implanted so that the electrodes 706 are placed on and / or around one or more targets to which the neural stimulation pulses are to be delivered, and the implantable stimulator 704 is implanted subcutaneously and connected to the (multiple) lead 708 at the time of implantation.

[0077] Figure 8An embodiment of an external programming device 802 of an implantable neurostimulation system such as system 600 is shown. External programming device 802 represents an example of programming device 102 or 302 and can be implemented, for example, as CP 630 and / or RC 632. External programming device 802 includes external telemetry circuitry 852, external storage device 818, programming control circuitry 816, and user interface 810.

[0078] The external telemetry circuit 852 provides the external programming device 802 with wireless communication with another device such as the implantable stimulator 704 via the wireless communication link 640, including transmitting a plurality of stimulation parameters to the implantable stimulator 704 and receiving information including patient data from the implantable stimulator 704. In one embodiment, the external telemetry circuit 852 also transmits power to the implantable stimulator 704 via an inductive coupling.

[0079] In various embodiments, the wireless communication link 640 may include an inductive telemetry link (near field telemetry link) and / or a far field telemetry link (RF telemetry link). This may allow for patient mobility where needed during programming and evaluation. For example, the wireless communication link 640 may include at least a far field telemetry link that allows communication between the external programming device 802 and the implantable stimulator 704 over relatively long distances (such as up to about 20 meters). The external telemetry circuit 852 and the implant telemetry circuit 744 each include an antenna and RF circuitry configured to support such wireless telemetry.

[0080] The external storage device 818 stores one or more stimulation waveforms for delivery during a neurostimulation therapy session (such as a DBS therapy session), and various parameters and building blocks for defining one or more waveforms. One or more stimulation waveforms may each be associated with one or more stimulation fields, and represent a pattern of neural stimulation pulses to be delivered to one or more stimulation fields during a neurostimulation therapy session. In various embodiments, each of the one or more stimulation waveforms may be selected for modification by a user and / or for programming a stimulation device such as an implantable stimulator 704 to deliver therapy. In various embodiments, each of the one or more stimulation waveforms may be defined pulse by pulse, and the external storage device 818 may include a pulse library storing one or more individually definable pulse waveforms that each define a pulse type in one or more pulse types. The external storage device 818 also stores one or more individually definable stimulation fields. Each of the one or more stimulation waveforms is associated with at least one field in the one or more individually definable stimulation fields. Each field of the one or more individually definable stimulation fields is defined by an electrode set, and the neural stimulation pulses are delivered through the electrode set. In various embodiments, each of the one or more individually definable fields is defined by an electrode set through which a neural stimulation pulse is delivered and the current distribution of the neural stimulation pulse on the electrode set. In one embodiment, the current distribution is defined by allocating a portion of the total pulse amplitude to each electrode in the electrode set. This definition of the current distribution may be referred to as "segmentation" herein. In another embodiment, the current distribution is defined by assigning an amplitude value to each electrode in the electrode set. For example, an electrode set may include 2 electrodes used as an anode and 1 electrode used as a cathode for delivering a neural stimulation pulse with a pulse amplitude of 4mA. The current distribution on the two electrodes used as the anode needs to be defined. In one embodiment, a certain percentage of the pulse amplitude is assigned to each of the 2 electrodes, such as 75% is assigned to electrode 1 and 25% is assigned to electrode 2. In another embodiment, the value of the amplitude is assigned to each of the 2 electrodes, such as 3mA is assigned to electrode 1, and 1mA is assigned to electrode 2. Even when adjusting the pulse amplitude, controlling the current as a percentage allows accurate and consistent distribution of the current between the electrodes. It lends itself to viewing the problem as manipulating the stimulus trajectory, and while keeping the stimulus amount constant, the stimulus is varied simultaneously across multiple contacts to move the trajectory. Controlling and displaying the total current through each electrode in an absolute value (e.g. mA) allows precise metering of the current through each specific electrode. It lends itself to varying the current one contact at a time (and allows the user to do so), to shaping the stimulus like a piece of clay (pushing / pulling one point at a time).

[0081] The programming control circuit 816 represents an example of the programming control circuit 316 and generates a plurality of stimulation parameters to be transmitted to the implantable stimulator 704 based on a specified neural stimulation program (e.g., a pattern of neural stimulation pulses represented by one or more stimulation waveforms and one or more stimulation fields, or at least some aspects of the pattern). The neural stimulation program can be created and / or adjusted by a user using the user interface 810 and stored in the external storage device 818. In various embodiments, the programming control circuit 816 can check the values ​​of the plurality of stimulation parameters against the safety rules to limit the values ​​to within the constraints of the safety rules. In one embodiment, the safety rules are heuristic rules.

[0082] User interface 810 represents an example of user interface 310 and allows a user to define patterns of neural stimulation pulses and perform various other monitoring and programming tasks. User interface 810 includes a display screen 856, a user input device 858, and an interface control circuit 854. Display screen 856 may include any type of interactive or non-interactive screen, and user input device 858 may include any type of user input device that supports the various functions discussed in this document, such as a touch screen, keyboard, keypad, touchpad, trackball, joystick, and mouse. In one embodiment, user interface 810 includes a GUI. As will be appreciated by those skilled in the art, the GUI may also allow a user to perform any functions discussed in this document as appropriate for graphical presentation and / or editing.

[0083] The interface control circuit 854 controls the operation of the user interface 810, including responding to various inputs received by the user input device 858 and defining one or more stimulation waveforms. The interface control circuit 854 includes the stimulation control circuit 320.

[0084] In various embodiments, the external programming device 802 can have an operating mode including a configuration mode and a real-time programming mode. In the configuration mode (also referred to as the pulse mode configuration mode), the user interface 810 is activated and the programming control circuit 816 is deactivated. The programming control circuit 816 does not dynamically update the values ​​of multiple stimulation parameters in response to any changes in one or more stimulation waveforms. In the real-time programming mode, both the user interface 810 and the programming control circuit 816 are activated. The programming control circuit 816 dynamically updates the values ​​of multiple stimulation parameters in response to changes in the set of one or more stimulation waveforms, and transmits multiple stimulation parameters with updated values ​​to the implantable stimulator 704.

[0085] Fig. 9An embodiment of a stimulation control circuit 960 for selecting a neural stimulation mode using ESG is shown. In this document, a "neurostimulation mode" may refer to a set of stimulation parameters used to control the delivery of neural stimulation energy for a neural stimulation procedure, a neural stimulation treatment session, or any other delivery unit of neural stimulation. A neural stimulation mode may be defined by a neural stimulation procedure (including stimulation parameters).

[0086] The stimulation control circuit 960 can control the delivery of neural stimulation energy according to each test mode in a plurality of neural stimulation test modes, and can include a sensing input 962, a measurement circuit 964, and a selection circuit 966. The sensing input 962 can receive an ESG signal indicating a response to the delivered neural stimulation energy. The measurement circuit 964 can use the received ESG signal to determine one or more response parameters for each test mode in a plurality of neural stimulation test modes. The one or more response parameters can each indicate one or more characteristics of the response to the delivered neural stimulation energy. The selection circuit 966 can select a neural stimulation treatment mode from a plurality of stimulation test modes based on one or more response parameters and one or more selection criteria. In this document, a "neural stimulation test mode" can refer to a neural stimulation mode developed for evaluation purposes (such as for evaluating its efficacy in a patient by delivering neural stimulation energy to the patient according to a neural stimulation test mode), and a "neural stimulation treatment mode" can refer to a neural stimulation mode determined for treatment purposes (such as for treating a patient by delivering neural stimulation energy to the patient according to a determined neural stimulation treatment mode).

[0087] The selection performed by the selection circuit 966 may include selecting a type of stimulation waveform from a plurality of types of stimulation waveforms in a plurality of stimulation test patterns. FIG. 12A to FIG. 12D The discussion includes examples of types of stimulation waveforms.

[0088] The response to the delivered neural stimulation energy includes a neural response induced by the delivered neural stimulation energy, referred to as an induced response. The one or more response parameters may include one or more neural response parameters each indicating one or more characteristics of the induced response. The measurement circuit 964 may use the received ESG signal to determine one or more neural response parameters for each test mode in a plurality of neural stimulation test modes. The selection circuit 966 may select a neural stimulation treatment mode from a plurality of stimulation test modes based on the one or more neural response parameters and one or more selection criteria.

[0089] Fig.10is a graph showing examples of neural responses seen on ESG induced by neural stimulation pulses. The neural responses shown are spinal responses seen on the ESG signal and produced by stimulation with electrical pulses having different amplitudes. The stronger spinal responses produced by stimulation with higher pulse amplitudes are characterized by larger amplitudes and different shapes, including, for example:

[0090] Larger N1-to-P2 amplitudes, where N1 is the first negative peak in the evoked response, associated with the response of faster fibers (such as Aβ fibers and myelinated fibers), and P2 is the second positive peak in the evoked response, associated with the response of slower fibers;

[0091] Greater N1 to P2 curve length;

[0092] Greater overall ESG curve length;

[0093] Larger ESG area under the curve (area between ESG and zero volt baseline);

[0094] Greater P2 peak latency, which is the time interval between the nerve stimulation pulse and the P2 of the evoked response and indicates recruitment of slower (smaller diameter) fibers; and

[0095] • The presence of N2 and P3, where N2 is the second negative peak in the evoked response and P3 is the third positive peak in the evoked response, which are associated with the responses of even much slower fibers (e.g., Aδ fibers).

[0096] One or more neural response parameters used to select a neural stimulation treatment mode from a plurality of stimulation test modes can be derived from such characteristics of the evoked response seen on the ESG signal.In various embodiments, one or more neural response parameters can be measured from the ESG signal and / or a derivative of the ESG signal.

[0097] In one embodiment, a criterion for selecting a neural stimulation therapy mode from a plurality of stimulation test modes includes selecting a test mode corresponding to a maximum evoked response identified from evoked responses corresponding to the plurality of neural stimulation test modes. The evoked response may include a response evoked by a stimulus such as a stimulation pulse or any stimulus unit considered as a single stimulus. Examples of one or more neural response parameters used with this selection criterion include:

[0098] The area under the curve (the area between the ESG signal and the evoked response or baseline over another specified period, also referred to in this document as the area under the curve), which can be determined using:

[0099]

[0100] Where A is the area under the curve, n is the time index, y is the data time series, and N is the index of the last data sample in the time series;

[0101] Curve length (duration of the induced response measured from the ESG signal, which can be determined using:

[0102]

[0103] Where CL is the curve length;

[0104] N1 to P2 amplitude (difference between the amplitudes of N1 and P2); and / or

[0105] • Curve length of the derivative of the ESG (the duration of the evoked response is measured from the derivative of the ESG signal).

[0106] In another embodiment, the criteria for selecting a neurostimulation treatment mode from a plurality of stimulation test modes include selecting a test mode that maximizes the overlap between the area of ​​the body with pain (the painful dermatome) and the dermatome where the patient feels the paresthesia sensation produced by the stimulation mode. The test mode that achieves this maximum pain-paresthesia overlap is identified from the induced responses corresponding to the plurality of neurostimulation test modes. The selection can also be accomplished using patient feedback and by comparison with previously recorded ESG signals, and the test mode is identified based on similarity to portions of the previously recorded ESG signals corresponding to the maximum pain-paresthesia overlap.

[0107] In various embodiments, these two criteria can be used alone, in combination with each other, or in combination with one or more other criteria, or one or more other criteria can be used to select a neurostimulation treatment mode from a plurality of stimulation test modes. In various embodiments, a plurality of neurostimulation test modes allow the evaluation of various waveforms and / or fields (stimulation sites) to select a neurostimulation treatment mode including a suitable or optimal waveform, field, or a combination of waveforms and fields according to one or more selection criteria. In various embodiments, the evaluation process can be completed automatically. For example, the stimulation control circuit 960 can control the delivery of neurostimulation energy by automatically sequencing a plurality of neurostimulation test modes. In various embodiments, the evaluation process can be completed manually. For example, the stimulation control circuit 960 can control the delivery of neurostimulation energy by allowing the user to manually input and / or start each test mode in a plurality of neurostimulation test modes.

[0108] Fig.11An embodiment of a system 1100 for delivering neural stimulation is shown, the system including a stimulation control circuit 1160 for selecting a neural stimulation mode using ESG. System 1100 can be implemented in a neural stimulation system such as systems 100, 500, and 600 and used to select a neural stimulation mode to be used in the system to control the delivery of neural stimulation energy.

[0109] The system 1100 may include a stimulation output circuit 1170 to deliver neural stimulation energy through a plurality of electrodes. Examples of stimulation output circuits 1170 implemented in a neural stimulation system include stimulation output circuits 212. Examples of a plurality of electrodes include electrodes 106, 206, 406, 506, 606, and 706. The stimulation output circuit 1170 may generate one or more stimulation waveforms, including one or more active recharging waveforms and / or one or more passive recharging waveforms.

[0110] System 1100 may include an ESG sensor 1174 to sense at least one ESG signal. ESG sensor 1174 implemented in a neurostimulation system may include electrodes that may be positioned to sense ESG and sensing circuitry for generating ESG signals for use by stimulation control circuit 1160. The electrodes may be incorporated into a lead system of a neurostimulation system, such as lead systems 208, 408, 508, 608, and 708, and the sensing circuitry may be included in sensing circuit 742.

[0111] The stimulation control circuit 1160 may represent an example of the stimulation control circuit 960 and may control the delivery of neural stimulation energy according to a test mode selected from a plurality of neural stimulation test modes. The system 1100 may include a storage circuit 1172 for storing a plurality of neural stimulation test modes. In one embodiment, the stimulation control circuit 1160 and the storage circuit 1172 implemented in the neural stimulation system include control circuits and storage devices of a stimulation device, such as the stimulation control circuit 214 of the stimulation device 204 or the stimulation control circuit 714 of the implantable stimulator 704, and the implant storage device 746 of the implantable stimulator 704. In another embodiment, the stimulation control circuit 1160 and the storage circuit 1172 implemented in the neural stimulation system include control circuits and storage devices of a programming device, such as the stimulation control circuit 320 of the programming device 302 or the external programming device 802, and the external storage device 818 of the external programming device 802.

[0112] Each neural stimulation mode (test or treatment mode) is defined by stimulation parameters (e.g., defined by a neural stimulation program that includes the stimulation parameters). The stimulation parameters may include one or more waveforms that each specify a temporal pattern of neural modulation energy. The one or more waveforms may include one or more passive recharging waveforms and / or one or more active recharging waveforms. FIG. 12A to FIG. 12I Examples of types of stimulation waveforms are shown. Each of the stimulation waveforms shown includes stimulation pulses that each include a stimulation (charge injection) phase, a recharge (charge recovery) phase, and an inter-interval delay (which can be programmed to zero, i.e., no inter-interval delay). The type of stimulation waveform may be defined, for example, by one or more of the following:

[0113] Active or passive charging (i.e. whether the charging phase is actively or passively driven);

[0114] The shape of the stimulation and / or recharge phases (e.g., rectangular, sinusoidal, or triangular); and

[0115] • Polarity of stimulation phase (eg, cathodic, anodic, or alternating).

[0116] Fig. 12A An example of a passive recharging waveform is shown where the stimulation phase is a square wave pulse. FIG. 12B to FIG. 12D Each shows an example of an active recharge waveform in which the stimulation phase and the recharge phase have asymmetric pulse shapes. Fig. 12B An example of an active recharge waveform is shown where the stimulation phase and the recharge phase are each square wave pulses. Fig. 12C An example of an active recharge waveform is shown, where the stimulation phase and the recharge phase are each sine wave pulses. Fig.12D An example of an active recharge waveform is shown, where the stimulation phase and the recharge phase are each triangle wave pulses. FIG. 12E to FIG. 12I Each shows an example of an active recharge waveform in which the stimulation phase and the recharge phase have asymmetric pulse shapes. Fig.12E An example of an active recharge waveform is shown where the anodal stimulation phase and the cathodic recharge phase are rectangular wave pulses with different amplitudes. Fig.12F An example of an active recharge waveform is shown where the cathodic stimulation phase and the anodic recharge phase are rectangular wave pulses with different amplitudes. Figure 12G An example of an active recharge waveform is shown in which the stimulation phase and recharge phase have alternating polarity (e.g., an anodic stimulation phase with a cathodic recharge phase, followed by a cathodic stimulation phase with an anodic recharge phase, and repeating) while being rectangular wave pulses with different amplitudes. Fig.12H An example of an active recharge waveform is shown, where the anodal stimulation phase and the cathodal recharge phase are rectangular wave pulses with different amplitudes and long interval delays (i.e., the one with the longer interval delay). Fig.12E waveform). Fig.12I An example of an active recharge waveform with a long interphase delay is shown, and the stimulation phase and the recharge phase have alternating polarity and are rectangular wave pulses with different amplitude delays (i.e., with a longer interphase delay). Figure 12GFor the purpose of illustration, these waveforms are shown by way of example and not by way of limitation. FIG. 12A to FIG. 12I Each waveform shown in may have opposite polarities, and various polarities and pulse shapes may be combined according to a neural stimulation mode designed by a person skilled in the art.

[0117] The stimulation parameters may also include one or more fields that each specify the spatial distribution of neural stimulation energy on the plurality of electrodes. In one embodiment, each field is specified by one or more active electrodes selected from the plurality of electrodes. In another embodiment, each field is specified by a subdivision of the current flowing through each of the plurality of electrodes.

[0118] In various embodiments, selecting a neurostimulation therapy mode from a plurality of neurostimulation test modes may include, for example, selecting a therapy parameter from a plurality of test parameters or selecting a therapy parameter set from a plurality of test parameter sets. For example, selecting a neurostimulation therapy mode from a plurality of neurostimulation test modes may include, for example, selecting a therapy waveform from a plurality of test waveforms and / or selecting a therapy field from a plurality of test fields.

[0119] Back to Fig.11 , stimulation control circuit 1160 may include sensing input 1162, measurement circuit 1164, selection circuit 1166, and adjustment circuit 1168. Sensing input 1162, measurement circuit 1164, and selection circuit 1166 may represent examples of sensing input 962, measurement circuit 964, and selection circuit 966, respectively.

[0120] Sensing input 1162 may receive ESG signals from ESG sensor 1174. The ESG signals are indicative of responses induced by neural stimulation energy delivered from the stimulation output circuit. In various embodiments, sensor 1174 may sense one or more ESG signals to be received by sensing input 1162, depending on the need to obtain information sufficient to select a neural stimulation therapy mode.

[0121] Measurement circuit 1164 can determine one or more neural response parameters using the ESG signal received by sensing input 1162. The one or more neural response parameters each indicate one or more characteristics of the induced response. The one or more neural response parameters each have values ​​corresponding to a plurality of neural stimulation test patterns. The values ​​each correspond to a test pattern in the plurality of neural stimulation test patterns.

[0122] The selection circuit 1166 can select a neural stimulation therapy mode from a plurality of stimulation test modes for controlling the delivery of neural stimulation energy based on one or more neural response parameters and one or more selection criteria. In one embodiment, the selection circuit 1166 selects the neural stimulation therapy mode based on a neural response parameter. The neural response parameter has a plurality of values ​​corresponding to a plurality of neural stimulation modes. The neural stimulation therapy mode to be selected is a test mode corresponding to an optimal value among the plurality of values. In another embodiment, the selection circuit 1166 selects the neural stimulation therapy mode based on a plurality of neural response parameters (e.g., parameter metrics). The plurality of neural response parameters have a plurality of values ​​corresponding to a plurality of neural stimulation test modes. The neural stimulation therapy mode to be selected is a test mode corresponding to an optimal value set among a plurality of value sets. One or more selection criteria define an optimal value or an optimal value set. Examples of optimal values ​​or optimal value sets include:

[0123] (a) the value or set of values ​​that maximizes or minimizes the overall spinal column (DC) response;

[0124] (b) a value or set of values ​​that maximizes or minimizes the response of a particular DC fiber (e.g., myelinated DC fibers, unmyelinated DC fibers, Aβ fibers, Aδ fibers, and fast or slow fibers); and

[0125] (c) A value or set of values ​​that maximizes the response of a fiber group while minimizing the response of another fiber group (e.g., maximizing the response of Aβ fibers while minimizing the response of Aδ fibers, or maximizing the response of fast fibers while minimizing the response of slow fibers).

[0126] These responses of different DC fiber types can be determined by extracting ECAP features from the ESG signal. Examples of such features include:

[0127] Area under the curve (e.g., the area under the curve for different time windows involving different relevant ECAP peaks in the ESG signal associated with faster or slower fibers);

[0128] curve length or relative curve length, where relative curve length refers to measuring the curve length over two different time windows and comparing the two measured curve lengths by subtraction or division, where the first time window includes P2 and the second window includes P3 (note that the relative curve length can be defined on a time window over any part of the ESG signal, such as a first time window from the onset of stimulation to 0.4 ms, and a second time window from 0.8 ms to 2.2 ms, where the curve lengths of these time windows may correspond to the curve length of the stimulation artifact and the curve length of the N1 to P2 response, respectively);

[0129] N1 to P2 amplitude or other peak-to-peak amplitude specified for each of the two peaks;

[0130] P2 peak delay;

[0131] Morphological changes; and

[0132] • The curve length of the derivative (slope) of the ESG signal.

[0133] One or more neural response parameters may include any one or any combination of these features (e.g., any linear or nonlinear mathematical combination of any two or more of these features). Any of these features (neural response parameters) may be determined for any particular time window. Examples of using morphological changes as features include using wavelets to detect or identify specific signal shapes. A known ECAP response or a change or cessation thereof may be detected using wavelets. Multiple "wavelet" templates corresponding to different shape morphologies of neural responses may be stored to allow detection of changes in neural responses (e.g., thinning or widening) using wavelets, etc.

[0134] If each selection process for a neurostimulation treatment mode takes time t min , then after making the selection, the selection circuit 1166 can min The next selection (e.g., update selection) is made after t has passed. If selection is made periodically by the selection circuit with a period ti, ti must be greater than t min Longer (ie ti>t min In other words, the selection circuit 1166 can update the selection at a frequency fi (fi = 1 / ti), which must be lower than 1 / t min. In one embodiment, the selection circuit 1166 makes an initial selection of a neurostimulation treatment mode and does not need to be updated periodically or need to follow another predetermined schedule. In another embodiment, the selection circuit 1166 updates the selection only when a need arises, such as when a user changes the stimulation field (e.g., by activating different electrodes or modifying the subdivisions). In another embodiment, the selection circuit 1166 frequently checks the selection, such as periodically or by following a schedule, and updates the selection in response to such a need identified by the check. One reason is that the spinal cord is surrounded by cerebrospinal fluid (CSF). The CSF acts as a buffer to protect the spinal cord from breaking during forceful movement of the body. The spinal cord moves softly and freely inside the CSF contained within the dura mater, which is a bag-like membrane structure that holds the CFS around the spinal cord together. During physical movement of the body, the spinal cord moves in three-dimensional space. Therefore, the position of the electrode (e.g., an epidural electrode) relative to the spinal cord changes. The electrode is typically stabilized within the fatty tissue of the epidural space. As the spinal cord moves, its distance to each of the electrodes changes, resulting in changes in the sensed ESG. Such changes may include changes in the neural and non-neural components of the ESG. The selection circuit 1166 may be configured to compensate for such changes by checking and updating the selection of the neural stimulation treatment mode at a desired frequency, such as a frequency determined empirically. This frequency may be set to be at a frequency less than 1 / t min The value of .

[0135] After selecting a neural stimulation therapy mode, stimulation control circuit 1160 may control the delivery of neural stimulation energy from stimulation output circuit 1170 in accordance with the selected neural stimulation therapy mode. System 1100 may include adjustment circuit 1168 for adjusting one or more stimulation parameters of the selected neural stimulation therapy mode based on one or more neural response parameters measured after delivery of neural stimulation energy in accordance with the neural stimulation therapy mode has begun. In various embodiments, adjustment circuit 1168 may adjust one or more stimulation parameters of the selected neural stimulation therapy mode so that the value of each of the adjusted one or more stimulation parameters remains within a specified range.

[0136] In various embodiments, while delivering neural stimulation energy according to the neural stimulation therapy mode, ESG sensor 1174 senses and sensing input 1162 receives the ESG signal, and measurement circuit 1164 determines one or more neural response signals (which may be the same or different than the one or more neural response signals determined for selecting the neural stimulation therapy mode). Regulation circuit 1168 adjusts one or more stimulation parameters to automatically maintain activation of various DC fibers by increasing or decreasing the intensity of the stimulation and / or by steering the stimulation field into a direction that maintains activation. In various embodiments, regulation circuit 1168 may maintain an optimized neural response by adjusting one or more stimulation parameters to, for example:

[0137] Limit changes in neural signal morphology to within a specified tolerance range;

[0138] Limit the change in amplitude from N1 to P2 to within the specified tolerance range;

[0139] Limit the change in the amplitude from P2 to N2 to within the specified tolerance range;

[0140] Limit the change in length of the N1 to P2 curve to within the specified tolerance range;

[0141] Limit the change in length of the P2 to N2 curve to within the specified tolerance range;

[0142] · constraining the variation in the area under the curve of each of the peaks in the induced response to within a specified tolerance range;

[0143] · limiting the variation of each of the delay of P2 and the delay of N2 to within a specified tolerance range; and / or

[0144] Limit changes in ESG curve length, range, or area under the curve to a specified time window

[0145] Examples of stimulation parameters that may be adjusted by regulation circuit 1168 to maintain an optimized neural response may include any of any combination of amplitude (e.g., current amplitude), pulse width, frequency, inter-interval delay, duration of the stimulation phase (while maintaining charge balance), duration of the recharge phase (while maintaining charge balance), cycle-on duration, and cycle-off duration.

[0146] Fig.13An embodiment of a display screen area 1380 that allows a user to select a neural stimulation mode using an ESG is shown. Display screen area 1380 can be part of a display screen (e.g., a window) of a user interface (such as presentation device 856 of user interface 810). The user interface also includes a user input device, such as user input device 858. In embodiments where a user can manually select a neural stimulation treatment mode from a plurality of neural stimulation test modes, the user input device is used to receive a selection from the user.

[0147] The selection circuit 1166 may cause one or more neural response parameters and / or their representations of a plurality of neural stimulation test modes to be displayed in the display screen area 1380 for measured values ​​or value sets. In various embodiments, the selection circuit 1166 may also cause instructions to guide the user to select a neural stimulation treatment mode based on the display information to be displayed in the display screen area 1380. In the illustrated embodiment, bars 1386A to 1386E each represent an amount of activation (e.g., DC corresponding amplitude) or pain paresthesia overlap resulting from delivering neural stimulation energy in accordance with one of several (shown as 5 by way of example and not limitation) neural stimulation test modes. The height of each of the bars 1386A to 1386E is determined based on the measured values ​​or value sets of one or more neural response parameters in one of the neural stimulation test modes. The selection circuit 1166 may also cause an optimal value and / or an optimal or suitable range of activation amount or pain coverage to be displayed in the display screen area 1380. In the illustrated embodiment, the selection circuit 1166 causes the display of an optimal value (height) 1382 and an optimal or suitable range defined by an upper threshold 1383 and a lower threshold 1384. In Fig.13 In the example of various heights of bars 1386A to 1386E shown in , the user may select test mode number 2 as the neural stimulation treatment mode because the corresponding bar 1386B has a height closest to the optimal value 1382, or may select test mode number 4 for compelling reasons (e.g., significantly lower stimulation intensity with less power consumption) because the corresponding bar 1386D has a height with an optimal or suitable range, while test mode numbers 1, 3 and 5 are not selected because their corresponding bars 1386A, 1386C and 1386E are outside the optimal or suitable range.

[0148] The illustrated embodiment can be used with various selection criteria, such as selection criteria based on maximum induced response and selection criteria based on maximum pain-paresthesia overlap as discussed above. The height (i.e., activation amount or pain coverage) of each of bars 1386A to 1386E can quantitatively indicate the magnitude of the induced response (e.g., DC response) or the degree of similarity (e.g., correlation coefficient) to a previously recorded ESG signal known to maximize pain-paresthesia overlap. Note that the optimal or suitable range can be defined by a single threshold (e.g., lower threshold 1384, when optimal means a maximum value without a specified upper limit).

[0149] Fig.14 An embodiment of a method 1490 for delivering neural stimulation, including selecting a neural stimulation mode using ESG, is shown. In one embodiment, the method 1490 is performed using the system 1100, wherein the stimulation control circuit 1160 is configured (e.g., programmed) to perform selection of a neural stimulation mode in accordance with the present subject matter. The method 1400 can be performed to select a neural stimulation treatment mode from a plurality of neural stimulation test modes. In various embodiments, the selection can include selecting a waveform that specifies a temporal pattern of neural modulation energy and / or selecting a field that specifies a spatial distribution of neural stimulation energy on a plurality of electrodes. The waveform can be an active recharge waveform or a passive recharge waveform.

[0150] At 1491, the delivery of neural stimulation energy is controlled according to each test mode in a plurality of neural stimulation test modes. At 1492, an ESG signal is received. In various embodiments, the ESG signal may be sensed epidurally using one or more electrodes placed on the spinal cord and / or intradurally using one or more electrodes placed (at least partially) within the spinal cord. The ECG signal indicates a response induced by the delivered neural stimulation energy. At 1493, one or more neural response parameters for each test mode in a plurality of neural stimulation test modes are determined using the received ESG signal. The one or more neural response parameters each indicate one or more characteristics of the induced response. As an example, although method 1490 relates to selecting a neural stimulation treatment mode based on one or more neural parameters, the present subject matter may also be applied to selecting a neural stimulation treatment mode based on other parameters that can be derived from measurements of ESG.

[0151] At 1494, a neural stimulation therapy mode is selected from a plurality of stimulation test modes based on one or more neural response parameters and one or more selection criteria. In various embodiments, the selection may be made automatically, manually, or automatically but with input from a user. In various embodiments, the determination at 1493 may include determining values ​​of one or more neural response parameters that each correspond to a test mode in a plurality of neural stimulation test modes, and the selection at 1494 may include selecting a test mode corresponding to a value in the determined values ​​identified according to one or more selection criteria. According to one example of a selection criterion, at 1494, a test mode corresponding to the largest induced response identified from the induced responses corresponding to the plurality of neural stimulation test modes will be selected. In order to identify the largest induced response, the one or more neural response parameters to be determined at 1493 may include a curve area as the area between the ESG signal and the baseline over a specified time interval, a curve length as the duration of the induced response over a specified time interval, a peak-to-peak amplitude as the difference between the amplitudes of two specified types of peaks in the ESG signal, or at least one of the one or more neural response parameters measured from the derivative of the received ESG signal. According to one example of another selection criterion, the test pattern corresponding to the maximum pain-paresthesia overlap identified from the induced responses corresponding to multiple neural stimulation test patterns will be selected. In various embodiments, one or more selection criteria for selecting a neural stimulation treatment mode may include either or both of these two criteria, any one or more other suitable criteria, or any combination of these two and other criteria. In one embodiment, selecting a neural stimulation treatment mode from multiple stimulation test patterns includes selecting a type of stimulation waveform from multiple types of stimulation waveforms in the multiple stimulation test patterns. For example, multiple stimulation test patterns may include multiple types of stimulation waveforms (e.g., active recharge waveforms with different waveform shapes), and the neural stimulation treatment mode corresponds to the most appropriate type of stimulation waveform identified according to one or more selection criteria.

[0152] At 1495, the delivery of neural stimulation energy is controlled in accordance with the selected neural stimulation therapy mode. At 1496, one or more stimulation parameters of the selected neural stimulation therapy mode are adjusted based on one or more neural response parameters measured after the delivery of neural stimulation energy in accordance with the neural stimulation therapy mode has begun. This adjustment is intended to maintain the value of each of the adjusted one or more stimulation parameters within a specified range during the delivery of neural stimulation energy in accordance with the neural stimulation therapy mode, so that the induced response obtained using the selected neural stimulation therapy mode can be maintained throughout the treatment. In various embodiments, steps 1491 to 1494 can be repeated when the induced response obtained using the selected neural stimulation therapy mode can no longer be maintained by adjusting one or more stimulation parameters. This can be accomplished by, for example, periodically checking the performance of the current selection and / or updating the selection when such a need is detected.

[0153] It should be understood that the above detailed description is intended to be illustrative, rather than restrictive. After reading and understanding the above description, other embodiments will be apparent to those skilled in the art. Therefore, the scope of the present invention should be determined with reference to the full scope of the equivalents given by the appended claims and these claims.

Claims

1. A system for delivering neural stimulation energy to a patient having a spinal cord via a plurality of electrodes, the system comprising: a stimulation control circuit configured to control delivery of the neural stimulation energy in accordance with each of a plurality of neural stimulation test patterns, the neural stimulation test patterns comprising stimulation waveforms, each of the stimulation waveforms specifying a temporal pattern of neural modulation energy comprising a waveform type selected from a plurality of waveform types including various recharge waveforms, the stimulation control circuit comprising: a sensing input configured to receive an electromyelogram (ESG) signal recording electrical activity from the spinal cord, the electrical activity including a response to the delivered neurostimulation energy; measurement circuitry configured to determine one or more response parameters for each of the plurality of neural stimulation test patterns using the received ESG signals, the one or more response parameters each indicating one or more characteristics of a response to the delivered neural stimulation energy; and A selection circuit is configured to select a neural stimulation treatment mode from the plurality of neural stimulation test modes based on the one or more response parameters and one or more selection criteria, the selection comprising selecting a waveform type from a plurality of waveform types in the plurality of neural stimulation test modes.

2. The system of claim 1, wherein the selection circuit is configured to select a neural stimulation therapy mode from the plurality of neural stimulation test modes periodically or in response to a need for a selection update being identified.

3. A system according to any of the preceding claims, wherein the measurement circuit is configured to determine one or more neural response parameters among the one or more response parameters, each of the one or more neural response parameters indicating one or more characteristics of an induced response, each of the induced responses being a neural response induced by the delivered neural stimulation energy, and the selection circuit is configured to select the neural stimulation treatment mode from the multiple neural stimulation test modes based on the one or more neural response parameters and the one or more selection criteria.

4. The system of any of the preceding claims, wherein the neural stimulation test modes are each defined by one or more of a stimulation waveform, and the plurality of waveform types includes an active recharge waveform.

5. A system according to any of the preceding claims, wherein the neural stimulation patterns are each defined by one or more fields, each of which specifies the spatial distribution of the neural stimulation energy across the plurality of electrodes.

6. A system according to any one of claims 3 to 5, wherein the measurement circuit is further configured to determine the values ​​of the one or more neural response parameters that each correspond to a test mode in the multiple neural stimulation test modes, and the selection circuit is further configured to select the neural stimulation treatment mode by selecting a test mode corresponding to a value in the determined values ​​identified according to the one or more selection criteria.

7. A system according to claim 6, wherein the selection circuit is configured to select the neural stimulation therapy mode by selecting a test pattern corresponding to a maximum induced response identified from the induced responses corresponding to the multiple neural stimulation test patterns.

8. The system of claim 7, wherein the measurement circuit is further configured to determine an area under a curve for the one or more neural response parameters, the area under a curve being an area between the ESG signal and a baseline over a specified time interval.

9. The system of claim 7, wherein the measurement circuit is further configured to determine a curve length of the one or more neural response parameters, the curve length being the duration of an evoked response within a specified time interval.

10. The system of claim 7, wherein the measurement circuit is further configured to determine a peak-to-peak amplitude of the one or more neural response parameters, the peak-to-peak amplitude being a difference between amplitudes of two specified types of peaks in the ESG signal.

11. A system according to claim 7, wherein the measurement circuit is further configured to generate a derivative of the received ESG signal, and is further configured to use the generated derivative of the received ESG signal to determine one or more additional neural response parameters, each of which indicates one or more additional characteristics of the induced response.

12. A system according to any one of claims 6 to 11, wherein the selection circuit is configured to select the neural stimulation treatment mode by selecting a test pattern corresponding to the maximum pain-paresthesia overlap identified from the induced responses corresponding to the multiple neural stimulation test patterns.

13. The system of claim 12, wherein the selection circuit is configured to compare the received ESG signal to a previously recorded ESG signal to identify the test pattern based on similarity to a portion of the previously recorded ESG signal corresponding to a maximum pain-paresthesia overlap.

14. A system according to any of the preceding claims, wherein the stimulation control circuit is also configured to control the delivery of the neural stimulation energy according to the selected neural stimulation therapy mode, and further includes an adjustment circuit configured to adjust one or more stimulation parameters of the selected neural stimulation therapy mode based on the one or more neural response parameters measured after the delivery of the neural stimulation energy according to the neural stimulation therapy mode has begun.

15. The system of claim 14, wherein the adjustment circuit is further configured to adjust the one or more stimulation parameters of the selected neural stimulation therapy mode so that the value of each of the adjusted one or more stimulation parameters remains within a specified range.

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