Patent Application
20220212014
This document relates generally to medical devices and more particularly to system and method for determining various thresholds for programming parameters of neurostimulation.
Neurostimulation, also referred to as neuromodulation, has been proposed as a therapy for a number of conditions. 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 such a therapy. An implantable neurostimulation system may include an implantable neurostimulator, also 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 with stimulation parameters controlling the delivery of the neurostimulation energy.
In one example, the neurostimulation energy is delivered in the form of electrical neurostimulation pulses. The delivery is controlled using stimulation parameters that specify spatial (where to stimulate), temporal (when to stimulate), and informational (patterns of pulses directing the nervous system to respond as desired) aspects of a pattern of neurostimulation pulses. Many current neurostimulation systems are programmed to deliver periodic pulses with one or a few uniform patterns or waveforms continuously or in bursts. However, the human nervous systems use neural signals having much more sophisticated patterns to communicate various types of information, including sensations of pain, pressure, temperature, etc. The nervous system may interpret an artificial stimulation with a simple pattern of stimuli as an unnatural phenomenon, and respond with an unintended and undesirable sensation and/or movement. For example, some neurostimulation therapies are known to cause paresthesia and/or feelings of vibration of non-targeted tissue or organ.
Recent research has shown that the efficacy and efficiency of certain neurostimulation therapies can be improved, and their side-effects can be reduced, by using patterns of neurostimulation pulses that emulate natural patterns of neural signals observed in the human body. This requires various parameters controlling the delivery of the neurostimulation pulses to change dynamically during a therapy session that may last for minutes to hours, depending on each patient's conditions and therapeutic goals.
An example (e.g., “Example 1”) of a system for delivering neurostimulation to tissue of a patient using a stimulation device coupled to a plurality of electrodes and controlling the delivery of the neurostimulation by a user may include a programming control circuit and a stimulation control circuit. The programming control circuit may be configured to program the stimulation device for delivering the neurostimulation according to a pattern of neurostimulation pulses defined by one or more stimulation waveforms. The stimulation control circuit may be configured to determine the pattern of neurostimulation pulses with the one or more stimulation waveforms constrained by one or more thresholds each being a limit for a parameter of waveform parameters defining the one or more stimulation waveforms. The stimulation control circuit may include threshold circuitry that may be configured to receive one or more known values of the one or more thresholds and to determine needed values of the one or more thresholds by executing an algorithm allowing for prediction of the needed values of the one or more thresholds based on the one or more known values.
In Example 2, the subject matter of Example 1 may optionally be configured such that the pattern of neurostimulation pulses includes the one or more stimulation waveforms and one or more stimulation fields each defined by a set of active electrodes through which one or more neurostimulation pulses of the pattern of neurostimulation pulses are delivered to the patient, and the stimulation control circuit includes waveform composition circuitry configured to determine the one or more stimulation waveforms and the one or more stimulation fields.
In Example 3, the subject matter of Example 2 may optionally be configured such that the one or more neurostimulation pulses each have an overall current amplitude, the one or more stimulation fields are each further defined by a fractionalization assigning a fraction of the overall current amplitude to each electrode of the set of active electrodes, and the waveform composition circuitry is further configured to determine the fractionalization for each of the one or more stimulation fields.
In Example 4, the subject matter of any one or any combination of Examples 2 and 3 may optionally be configured such that the threshold circuitry is further configured to receive the one or more known values of the one or more thresholds for each stimulation field of the one or more stimulation fields and to determine the needed values of the one or more thresholds for the each stimulation field.
In Example 5, the subject matter of any one or any combination of Examples 1 to 4 may optionally be configured such that the threshold circuitry is configured to determine one or more thresholds of a first parameter selected from the waveform parameters for one or more given values or one or more value ranges of one or more second parameters selected from the waveform parameters.
In Example 6, the subject matter of Example 5 may optionally be configured such that the threshold circuitry is configured to determine the one or more thresholds of the first parameter for one or more worse-case values of the one or more second parameters.
In Example 7, the subject matter of Example 6 may optionally be configured such that the threshold circuitry is configured to identify one or more worst cases in the pattern of neurostimulation pulses and determine the one or more worse-case values of the one or more second parameters being one or more values of the one or more second parameters under the identified one or more worst cases.
In Example 8, the subject matter of any one or any combination of Examples 6 and 7 may optionally be configured to further include a user interface configured to receive one or more user-defined worst cases in the pattern of neurostimulation pulses from the user and determine the one or more worse-case values of the one or more second parameters being one or more values of the one or more second parameters under the received one or more user-defined worst cases.
In Example 9, the subject matter of any one or any combination of Examples 5 to 8 may optionally be configured such that the first parameter is a pulse amplitude, the second parameter is a pulse width, and the threshold circuitry includes amplitude threshold circuitry configured to determine an amplitude threshold of the one or more thresholds. The amplitude threshold is a limit for the pulse amplitude for each given value or value range of the pulse width.
In Example 10, the subject matter of Example 9 may optionally be configured such that the amplitude threshold circuitry is configured to determine an amplitude threshold of the one or more thresholds. The amplitude threshold is a maximum value of the pulse amplitude for a maximum value of the pulse width in the each given value range of the pulse width.
In Example 11, the subject matter of Example 9 may optionally be configured such that the amplitude threshold circuitry is configured to determine needed values of the amplitude threshold using one or more known values of the amplitude threshold and a relationship between the pulse amplitude and the pulse width.
In Example 12, the subject matter of Example 11 may optionally be configured such that the amplitude threshold circuitry is configured to determine the needed values of the amplitude threshold using the one or more known values of the amplitude threshold and a strength-duration curve.
In Example 13, the subject matter of any one or any combination of Examples 1 to 12 may optionally be configured such that the stimulation control circuit is further configured to control timing of delivery of the pattern of neurostimulation pulses.
In Example 14, the subject matter of any one or any combination of Examples 1 to 13 may optionally be configured such that the stimulation device includes an implantable stimulation device configured to deliver the neurostimulation and to control the delivery of the neurostimulation using a plurality of stimulation parameters.
In Example 15, the subject matter of Example 14 may optionally be configured to further include a programmer including the programming control circuit and the stimulation control circuit. The programming control circuit is configured to generate the plurality of stimulation parameters according to the pattern of neurostimulation pulses and to transmit the plurality of stimulation parameters to the implantable stimulation device.
An example (e.g., “Example 16”) of a method for delivering neurostimulation to a patient using a stimulation device coupled to a plurality of electrodes and controlling the delivery of the neurostimulation by a user is also provided. The method may include determining one or more thresholds each being a limit for a parameter of waveform parameters defining one or more stimulation waveforms. This determination may include receiving one or more known values of one or more thresholds and determining needed values of the one or more thresholds by executing an algorithm allowing for prediction of the needed values of the one or more thresholds based on the one or more known values. The method may further include determining the one or more stimulation waveforms using constraints including the determined one or more thresholds, determining a pattern of neurostimulation pulses including the determined one or more stimulation waveforms, and programming the stimulation device for delivering the neurostimulation according to the determined pattern of neurostimulation pulses.
In Example 17, the subject matter of Example 16 may optionally further include determining the one or more known values of one or more thresholds by measuring from the patient.
In Example 18, the subject matter of any one or any combination of Examples 16 and 17 may optionally further include determining the algorithm for the patient using information including data collected from the patient.
In Example 19, the subject matter of any one or any combination of Examples 16 to 18 may optionally further include determining one or more stimulation fields each defined by a set of active electrodes through which one or more neurostimulation pulses of the pattern of neurostimulation pulses are delivered to the patient. The set of active electrodes is selected from the plurality of electrodes. The subject matter of receiving the one or more known values of one or more thresholds as found in any one or any combination of Examples 16 to 18 may optionally include receiving the one or more known values of one or more thresholds for each stimulation field of the one or more stimulation fields. The subject matter of determining the needed values of the one or more thresholds as found in any one or any combination of Examples 16 to 18 may optionally include determining the needed values of the one or more thresholds for the each stimulation field.
In Example 20, the subject matter of determining the one or more stimulation fields as found in Example 19 may optionally include determining a fractionalization for each of the one or more stimulation fields. The one or more neurostimulation pulses each have an overall current amplitude. The one or more stimulation fields are each further defined by a fractionalization assigning a fraction of the overall current amplitude to each electrode of the set of active electrodes.
comprises
In Example 21, the subject matter of the waveform parameters as found any one or any combination of Examples 19 and 20 may optionally include a pulse amplitude and a pulse width, the subject matter of determining the one or more thresholds as found any one or any combination of Examples 19 and 20 may optionally include determining an amplitude threshold being a maximum value of the pulse amplitude for each given value or range of values of the pulse width.
In Example 22, the subject matter of determining the amplitude threshold as found in any one or any combination of Examples 19 and 20 may optionally include determining a maximum value of the pulse amplitude for a maximum value of the pulse width in the each given range of values of the pulse width.
In Example 23, the subject matter of determining the amplitude threshold as found in any one or any combination of Examples 19 and 21 may optionally include determining needed values of the amplitude threshold using one or more known values of the amplitude threshold and a relationship between the pulse amplitude and the pulse width.
In Example 24, the subject matter of determining the amplitude threshold as found in Example 23 may optionally include determining the needed values of the amplitude threshold using the one or more known values of the amplitude threshold and a strength-duration curve.
In Example 25, the subject matter of Example 24 may optionally further include determining the strength-duration curve for each stimulation field of the one or more stimulation fields using information including data collected from the patient.
This Summary is an overview of some of the teachings of the present application and not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details about the present subject matter are found in the detailed description and appended claims. Other aspects of the disclosure will be apparent to persons skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part thereof, each of which are not to be taken in a limiting sense. The scope of the present disclosure is defined by the appended claims and their legal equivalents.
The drawings illustrate generally, by way of example, various embodiments discussed in the present document. The drawings are for illustrative purposes only and may not be to scale.
In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that the embodiments may be combined, or that other embodiments may be utilized and that structural, logical and electrical changes may be made without departing from the spirit and scope of the present invention. References to “an”, “one”, or “various” embodiments in this disclosure are not necessarily to the same embodiment, and such references contemplate more than one embodiment. The following detailed description provides examples, and the scope of the present invention is defined by the appended claims and their legal equivalents.
This document discusses, among other things, a method and system for determining tolerance limits for stimulation parameters when programming a stimulation device for delivering neurostimulation to a patient. In various embodiments, the neurostimulation may be delivered as sequenced programs that are not tonic, but include dynamically changing stimulation settings. For example, when the neurostimulation is delivered in a form of electrical pulses, stimulation parameters such as pulse amplitude, pulse width, pulse rate (frequency), and stimulation field (electrode configuration) may change continuously over time. Saving such sequenced programs to the stimulation device (e.g., an implantable pulse generator) of the patient may require setting various thresholds, limits, or set points for each stimulation parameter based on the patient's responses to the neurostimulation. The present subject matter provides for establishing such thresholds. In various embodiments, the present subject matter can facilitate stimulation device programming by ensuring therapy efficacy without consuming excessive energy and/or causing undesirable effects such as patient discomfort, particularly when a sequenced program of neurostimulation is to be programmed. An example of programming sequenced program of neurostimulation is discussed in U.S. Patent Application Publication No. 2017/0050033 A1, entitled “USER INTERFACE FOR CUSTOM PATTERNED ELECTRICAL STIMULATION”, assigned to Boston Scientific Neuromodulation Corporation, which is incorporated herein by reference in its entirety.
While simple neurostimulation programs may be tonic with its stimulation parameters remain unchanged with time, sequenced neurostimulation programs with sophisticated patterns of electrical pulses may include dynamic changes of parameters over time durations from microseconds to hours or longer. Throughout each program, the stimulation pulses are to be effective (e.g., evoking tissue responses as intended) while being tolerable to the patient (e.g., not causing pain, sensation, or discomfort to a level that is unacceptable or undesirable the patient, and not causing undesirable effects not sensed by the patient, such as raising blood pressure to an abnormal level). When the patient is allowed to adjust the neurostimulation, often he or she is to be prevented from modifying parameters in a way that can result in uncomfortable or painful stimulation. When the duration of a sequenced program is long (e.g., several minutes or hours), it may be impractical to evaluate all the parameter values in the entire program for the patient. Therefore, the present subject matter checks worst-case settings to establish threshold values for various parameters, such as by prediction, interpolation, and/or extrapolation, thereby eliminating the need to explicitly testing for every needed threshold value. When setting all the parameter values for the worse-case scenario is considered to be over-conservative, the value for a parameter may be set based on testing one or a few scenarios. In some embodiments, this can be done by using one or more known and/or learned relationship between various parameters.
In this document, a “user” includes a physician or other clinician or caregiver who treats the patient using system 100; a “patient” includes a person who receives or is intended to receive neurostimulation delivered using system 100. In various embodiments, the patient can be allowed to adjust his or her treatment using system 100 to certain extent, such as by adjusting certain therapy parameters and entering feedback and clinical effect information.
In various embodiments, programming device 102 can include a user interface 110 that allows the user to control the operation of system 100 and monitor the performance of system 100 as well as conditions of the patient including responses to the delivery of the neurostimulation. The user can control the operation of system 100 by setting and/or adjusting values of the user-programmable parameters.
In various embodiments, user interface 110 can include a graphical user interface (GUI) that allows the user to set and/or adjust the values of the user-programmable parameters by creating and/or editing graphical representations of various waveforms. Such waveforms may include, for example, a waveform representing a pattern of neurostimulation pulses to be delivered to the patient as well as individual waveforms that are used as building blocks of the pattern of neurostimulation pulses, such as the waveform of each pulse in the pattern of neurostimulation pulses. The GUI may also allow the user to set and/or adjust stimulation fields each defined by a set of electrodes through which one or more neurostimulation pulses represented by a waveform are delivered to the patient. The stimulation fields may each be further defined by the distribution of the current of each neurostimulation pulse in the waveform. In various embodiments, neurostimulation pulses for a stimulation period (such as the duration of a therapy session) may be delivered to multiple stimulation fields.
In various embodiments, system 100 can be configured for neurostimulation applications, including but not limited to SCS, DBS, PNS, and FES applications. User interface 110 can be configured to allow the user to control the operation of system 100 for neurostimulation.
In various embodiments, the number of leads and the number of electrodes on each lead depend on, for example, the distribution of target(s) of the neurostimulation and the need for controlling the distribution of electric field at each target. In one embodiment, lead system 208 includes 2 leads each having 8 electrodes.
In various embodiments, user interface 310 can allow for definition of a pattern of neurostimulation pulses for delivery during a neurostimulation therapy session by creating and/or adjusting one or more stimulation waveforms using a graphical method. The definition can also include definition of one or more stimulation fields each associated with one or more pulses in the pattern of neurostimulation pulses. As used in this document, a “stimulation program” can include the pattern of neurostimulation pulses including the one or more stimulation fields, or at least various aspects or parameters of the pattern of neurostimulation pulses including the one or more stimulation fields. In various embodiments, user interface 310 includes a GUI that allows the user to define the pattern of neurostimulation pulses and perform other functions using graphical methods. In this document, “neurostimulation programming” can include the definition of the one or more stimulation waveforms, including the definition of one or more stimulation fields.
In various embodiments, circuits of neurostimulation 100, including but not limited to its various embodiments discussed in this document, may be implemented using a combination of hardware and software. For example, the circuit of user interface 110, stimulation control circuit 214, programming control circuit 316, and stimulation control circuit 320, including but not limited to their various embodiments discussed in this document, may be implemented using an application-specific circuit constructed to perform one or more particular functions or a general-purpose circuit programmed to perform such function(s). Such a general-purpose circuit includes, but is not limited to, a microprocessor or a portion thereof, a microcontroller or portions thereof, and a programmable logic circuit or a portion thereof.
IPG 404 can include a hermetically-sealed IPG case 422 to house the electronic circuitry of IPG 404, an electrode 426 formed on IPG case 422, and an IPG header 424 for coupling the proximal ends of leads 408A and 408B. IPG header 424 may optionally also include an electrode 428. Electrodes 426 and/or 428 represent embodiments of electrode(s) 207 and may each be referred to as a reference electrode. Neurostimulation energy can be delivered in a monopolar (also referred to as unipolar) mode using electrode 426 or electrode 428 and one or more electrodes selected from electrodes 406. Neurostimulation energy can be delivered in a bipolar mode using a pair of electrodes of the same lead (lead 408A or lead 408B). Neurostimulation energy can be delivered in an extended bipolar mode using one or more electrodes of a lead (e.g., one or more electrodes of lead 408A) and one or more electrodes of a different lead (e.g., one or more electrodes of lead 408B).
The electronic circuitry of IPG 404 can include a control circuit that controls delivery of the neurostimulation energy. The control circuit can include a microprocessor, a digital signal processor, application specific integrated circuit (ASIC), or other type of processor, interpreting or executing instructions included in software or firmware. The neurostimulation energy can be delivered according to specified (e.g., programmed) modulation parameters. Examples of setting modulation parameters can include, among other things, selecting the electrodes or electrode combinations used in the stimulation, configuring an electrode or electrodes as the anode or the cathode for the stimulation, specifying the percentage of the neurostimulation provided by an electrode or electrode combination, and specifying stimulation pulse parameters. Examples of pulse parameters include, among other things, the amplitude of a pulse (specified in current or voltage), pulse duration (e.g., in microseconds), pulse rate (e.g., in pulses per second), and parameters associated with a pulse train or pattern such as burst rate (e.g., an “on” modulation time followed by an “off” modulation time), amplitudes of pulses in the pulse train, polarity of the pulses, etc.
An example of IPG 504 includes IPG 404. An example of lead system 508 includes one or more of leads 408A and 408B. In the illustrated embodiment, implantable lead system 508 is arranged to provide SCS to a patient, with the stimulation target being neuronal tissue in the patient's spinal cord. In various embodiments, the present subject matter can be applied to neurostimulation of any types and targets, including but not limited to SCS, DBS, PNS, and FES.
Implantable system 525 includes an implantable stimulator (also referred to as an IPG) 504, a lead system 508, and electrodes 506, which can represent an example of stimulation device 204, lead system 208, and electrodes 206, respectively. External system 502 can represent an example of programming device 302. In various embodiments, external system 502 can include one or more external (non-implantable) devices each allowing the user and/or the patient to communicate with implantable system 525. In some embodiments, external system 502 includes a programming device intended for the user to initialize and adjust settings for implantable stimulator 504 and a remote control device intended for use by the patient. For example, the remote control device may allow the patient to turn implantable stimulator 404 on and off and/or adjust certain patient-programmable parameters of the plurality of stimulation parameters.
The sizes and sharps of the elements of implantable system 525 and their location in body 599 are illustrated by way of example and not by way of restriction. An implantable system is discussed as a specific application of the programming according to various embodiments of the present subject matter. In various embodiments, the present subject matter may be applied in programming any type of stimulation device that uses electrical pulses as stimuli, regarding less of stimulation targets in the patient's body and whether the stimulation device is implantable.
ETM 634 may be standalone or incorporated into CP 630. ETM 634 may have similar pulse generation circuitry as IPG 604 to deliver neurostimulation energy according to specified modulation parameters as discussed above. ETM 634 is an external device that is typically used as a preliminary stimulator after leads 408A and 408B have been implanted and used prior to stimulation with IPG 604 to test the patient's responsiveness to the stimulation that is to be provided by IPG 604. Because ETM 634 is external it may be more easily configurable than IPG 604.
CP 630 can configure the neurostimulation 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., over a USB link) or by wireless telemetry using a wireless communications link 640. CP 630 also communicates with IPG 604 using a wireless communications link 640.
An example of wireless telemetry is based on inductive coupling between two closely-placed coils using the mutual inductance between these coils. This type of telemetry is referred to as inductive telemetry or near-field telemetry because the coils must typically be closely situated for obtaining inductively coupled communication. IPG 604 can include the first coil and a communication circuit. CP 630 can include or otherwise electrically connected to the second coil such as in the form of a wand that can be place near IPG 604. Another example of wireless telemetry includes a far-field telemetry link, also referred to as a radio frequency (RF) telemetry link. A far-field, also referred to as the Fraunhofer zone, refers to the zone in which a component of an electromagnetic field produced by the transmitting electromagnetic radiation source decays substantially proportionally to 1/r, where r is the distance between an observation point and the radiation source. Accordingly, far-field refers to the zone outside the boundary of r=λ/2π, where λ is the wavelength of the transmitted electromagnetic energy. In one example, a communication range of an RF telemetry link is at least six feet but can be as long as allowed by the particular communication technology. RF antennas can be included, for example, in the header of IPG 604 and in the housing of CP 630, eliminating the need for a wand or other means of inductive coupling. An example is such an RF telemetry link is a Bluetooth® wireless link.
CP 630 can be used to set modulation parameters for the neurostimulation after IPG 604 has been implanted. This allows the neurostimulation to be tuned if the requirements for the neurostimulation change after implantation. CP 630 can also upload information from IPG 604.
RC 632 also communicates with IPG 604 using a wireless link 340. RC 632 may be a communication device used by the user or given to the patient. RC 632 may have reduced programming capability compared to CP 630. This allows the user or patient to alter the neurostimulation therapy but does not allow the patient full control over the therapy. For example, the patient may be able to increase the amplitude of neurostimulation pulses or change the time that a preprogrammed stimulation pulse train is applied. RC 632 may be programmed by CP 630. CP 630 may communicate with the RC 632 using a wired or wireless communications link. In some embodiments, CP 630 is able to program RC 632 when remotely located from RC 632.
Implantable stimulator 704 may include a sensing circuit 742 that is optional and required only when the stimulator needs a sensing capability, stimulation output circuit 212, a stimulation control circuit 714, an implant storage device 746, an implant telemetry circuit 744, a power source 748, and one or more electrodes 707. Sensing circuit 742, when included and needed, senses one or more physiological signals for purposes of patient monitoring and/or feedback control of the neurostimulation. Examples of the one or more physiological signals include neural and other signals each indicative of a condition of the patient that is treated by the neurostimulation and/or a response of the patient to the delivery of the neurostimulation. Stimulation output circuit 212 is electrically connected to electrodes 706 through one or more leads 708 as well as electrodes 707, and delivers each of the neurostimulation pulses through a set of electrodes selected from electrodes 706 and electrode(s) 707. Stimulation control circuit 714 can represent an example of stimulation control circuit 214 and controls the delivery of the neurostimulation pulses using the plurality of stimulation parameters specifying the pattern of neurostimulation pulses. In one embodiment, stimulation control circuit 714 controls the delivery of the neurostimulation pulses using the one or more sensed physiological signals. Implant telemetry circuit 744 provides implantable stimulator 704 with wireless communication with another device such as CP 630 and RC 632, including receiving values of the plurality of stimulation parameters from the other device. Implant storage device 746 stores values of the plurality of stimulation parameters. Power source 748 provides implantable stimulator 704 with energy for its operation. In one embodiment, power source 748 includes a battery. In one embodiment, power source 748 includes a rechargeable battery and a battery charging circuit for charging the rechargeable battery. Implant telemetry circuit 744 may also function as a power receiver that receives power transmitted from an external device through an inductive couple. Electrode(s) 707 allow for delivery of the neurostimulation pulses in the monopolar mode. Examples of electrode(s) 707 include electrode 426 and electrode 418 in IPG 404 as illustrated in
In one embodiment, implantable stimulator 704 is used as a master database. A patient implanted with implantable stimulator 704 (such as may be implemented as IPG 604) may therefore carry patient information needed for his or her medical care when such information is otherwise unavailable. Implant storage device 746 is configured to store such patient information. For example, the patient may be given a new RC 632 and/or travel to a new clinic where a new CP 630 is used to communicate with the device implanted in him or her. The 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 for any necessary adjustment of the operation of implantable stimulator 704 based on the retrieved patient information. In various embodiments, the patient information to be stored in implant storage device 746 may include, for example, positions of lead(s) 708 and electrodes 706 relative to the patient's anatomy (transformation for fusing computerized tomogram (CT) of post-operative lead placement to magnetic resonance imaging (MRI) of the brain), clinical effect map data, objective measurements using quantitative assessments of symptoms (for example using micro-electrode recording, accelerometers, and/or other sensors), and/or any other information considered important or useful for providing adequate care for the patient. In various embodiments, the patient information to be stored in implant storage device 746 may include data transmitted to implantable stimulator 704 for storage as part of the patient information and data acquired by implantable stimulator 704, such as by using sensing circuit 742.
In various embodiments, sensing circuit 742 (if included), stimulation output circuit 212, stimulation control circuit 714, implant telemetry circuit 744, implant storage device 746, and power source 748 are encapsulated in a hermetically sealed implantable housing or case, and electrode(s) 707 are formed or otherwise incorporated onto the case. In various embodiments, lead(s) 708 are implanted such that electrodes 706 are placed on and/or around one or more targets to which the neurostimulation pulses are to be delivered, while implantable stimulator 704 is subcutaneously implanted and connected to lead(s) 708 at the time of implantation.
External telemetry circuit 852 provides external programming device 802 with wireless communication with another device such as implantable stimulator 704 via wireless communication link 640, including transmitting the plurality of stimulation parameters to implantable stimulator 704 and receiving information including the patient data from implantable stimulator 704. In one embodiment, external telemetry circuit 852 also transmits power to implantable stimulator 704 through an inductive couple.
In various embodiments, wireless communication link 640 can include an inductive telemetry link (near-field telemetry link) and/or a far-field telemetry link (RF telemetry link). External telemetry circuit 852 and implant telemetry circuit 744 each include an antenna and RF circuitry configured to support such wireless telemetry.
External storage device 818 stores one or more stimulation waveforms for delivery during a neurostimulation therapy session, as well as various parameters and building blocks for defining the one or more stimulation waveforms. The one or more stimulation waveforms may each be associated with one or more stimulation fields and represent a pattern of neurostimulation pulses to be delivered to the one or more stimulation field during the neurostimulation therapy session. In various embodiments, each of the one or more stimulation waveforms can be selected for modification by the user and/or for use in programming a stimulation device such as implantable stimulator 704 to deliver a therapy. In various embodiments, each waveform in the one or more stimulation waveforms is definable on a pulse-by-pulse basis, and external storage device 818 may include a pulse library that stores one or more individually definable pulse waveforms each defining a pulse type of one or more pulse types. External storage device 818 also stores one or more individually definable stimulation fields. Each waveform in the one or more stimulation waveforms is associated with at least one field of the one or more individually definable stimulation fields. Each field of the one or more individually definable stimulation fields is defined by a set of electrodes through a neurostimulation pulse is delivered. In various embodiments, each field of the one or more individually definable fields is defined by the set of electrodes through which the neurostimulation pulse is delivered and a current distribution of the neurostimulation pulse over the set of electrodes. In one embodiment, the current distribution is defined by assigning a fraction of an overall pulse amplitude to each electrode of the set of electrodes. Such definition of the current distribution may be referred to as “fractionalization” in this document. In another embodiment, the current distribution is defined by assigning an amplitude value to each electrode of the set of electrodes. For example, the set of electrodes may include 2 electrodes used as the anode and an electrode as the cathode for delivering a neurostimulation pulse having a pulse amplitude of 4 mA. The current distribution over the 2 electrodes used as the anode needs to be defined. In one embodiment, a percentage of the pulse amplitude is assigned to each of the 2 electrodes, such as 75% assigned to electrode 1 and 25% to electrode 2. In another embodiment, an amplitude value is assigned to each of the 2 electrodes, such as 3 mA assigned to electrode 1 and 1 mA to electrode 2. Control of the current in terms of percentages allows precise and consistent distribution of the current between electrodes even as the pulse amplitude is adjusted. It is suited for thinking about the problem as steering a stimulation locus, and stimulation changes on multiple contacts simultaneously to move the locus while holding the stimulation amount constant. Control and displaying the total current through each electrode in terms of absolute values (e.g. mA) allows precise dosing of current through each specific electrode. It is suited for changing the current one contact at a time (and allows the user to do so) to shape the stimulation like a piece of clay (pushing/pulling one spot at a time).
Programming control circuit 816 can represent an example of programming control circuit 316 and generates the plurality of stimulation parameters, which is to be transmitted to implantable stimulator 704, based on a specified stimulation program (e.g., the pattern of neurostimulation pulses as represented by one or more stimulation waveforms and one or more stimulation fields, or at least certain aspects of the pattern). The stimulation program may be created and/or adjusted by the user using user interface 810 and stored in external storage device 818. In various embodiments, programming control circuit 816 can check values of the plurality of stimulation parameters against safety rules to limit these values within constraints of the safety rules. In one embodiment, the safety rules are heuristic rules.
User interface 810 can represent an example of user interface 310 and allows the user to define the pattern of neurostimulation 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 screens, and user input device 858 may include any type of user input devices that supports the various functions discussed in this document, such as touchscreen, keyboard, keypad, touchpad, trackball, joystick, and mouse. In one embodiment, user interface 810 includes a GUI. The GUI may also allow the user to perform any functions discussed in this document where graphical presentation and/or editing are suitable as may be appreciated by those skilled in the art.
Interface control circuit 854 controls the operation of user interface 810 including responding to various inputs received by user input device 858 and defining the one or more stimulation waveforms. Interface control circuit 854 includes stimulation control circuit 320.
In various embodiments, external programming device 802 can have operation modes including a composition mode and a real-time programming mode. Under the composition mode (also known as the pulse pattern composition mode), user interface 810 is activated, while programming control circuit 816 is inactivated. Programming control circuit 816 does not dynamically updates values of the plurality of stimulation parameters in response to any change in the one or more stimulation waveforms. Under the real-time programming mode, both user interface 810 and programming control circuit 816 are activated. Programming control circuit 816 dynamically updates values of the plurality of stimulation parameters in response to changes in the set of one or more stimulation waveforms, and transmits the plurality of stimulation parameters with the updated values to implantable stimulator 704.
Stimulation control circuit 920 can include waveform composition circuitry 962 and threshold circuitry 964. Waveform composition circuitry 962 can determine the one or more stimulation waveforms constrained by one or more thresholds. The one or more thresholds are each being a limit for a parameter of waveform parameters defining the one or more stimulation waveforms. Threshold circuitry 964 can receive one or more known values of the one or more thresholds and determine needed values of the one or more thresholds by executing an algorithm allowing for prediction of the needed values of the one or more thresholds based on the one or more known values. In various embodiments, the one or more known values includes one or more values that can be determined based on data collected from the patient, and the needed values includes all the values needed during determination of the one or more stimulation waveforms. In some embodiments, stimulation control circuit 920 may include threshold circuitry 964 without waveform composition circuitry 962 or a limited version of waveform composition circuitry 962. For example, when system 960 is implemented as part of RC 632 to be given to the patient, RC 632 may only provide the patient with limited control of delivery of the neurostimulation such as to start the delivery, to stop the delivery, and to adjust the intensity of the neurostimulation pulses.
In various embodiments, the pattern of neurostimulation pulses defined by stimulation control circuit 920 can define a stimulation program of a segment of the stimulation program. Programming control circuit 916 can generate a plurality of stimulation parameters according to the pattern of neurostimulation pulses. In embodiments in which programming control circuit 916 is part of a programming device such as external programming device 802, programming control circuit 916 can transmit the plurality of stimulation parameters to implantable stimulator 704 to be used by stimulation control circuit 714 to control delivery of neurostimulation from stimulation output circuit 212. In various embodiments, the pattern of neurostimulation pulses are defined by the one or more stimulation waveforms and one or more stimulation fields. A stimulation program uses multiple stimulation fields if the electrode configuration is to change during the delivery of the neurostimulation according to a pattern of neurostimulation pulses. Each pulse in the pattern of neurostimulation pulses has a stimulation waveform being the waveform of the pulse and a stimulation field specifying electrodes through which the pulse is delivered. The one or more stimulation fields can each be defined by a set of active electrodes through which one or more neurostimulation pulses of the pattern of neurostimulation pulses are delivered to the patient. The set of active electrodes can be selected from a plurality of electrodes such as electrodes 206 and 207, including but not limited to their various embodiments as discussed in this document. In various embodiments, each neurostimulation pulse has an overall current amplitude, and the one or more stimulation fields are each further defined by a fractionalization assigning a fraction of the overall current amplitude to each electrode of the set of active electrodes.
In various embodiments, waveform composition circuitry 962 can determine the one or more stimulation waveforms, including the one or more stimulation fields, that define the pattern of neurostimulation pulses. Examples of waveform composition techniques that may be employed by waveform composition circuitry 1062 include, but are not limited to, those discussed in U.S. Pat. No. 9,737,717, entitled “GRAPHICAL USER INTERFACE FOR PROGRAMMING NEUROSTIMULATION PULSE PATTERNS”, U.S. Patent Application Publication No. 2016/0121126 A1, entitled “METHOD AND APPARATUS FOR PROGRAMMING COMPLEX NEUROSTIMULATION PATTERNS”, U.S. Patent Application Publication No. 2017/0050033 A1, entitled “USER INTERFACE FOR CUSTOM PATTERNED ELECTRICAL STIMULATION”, and U.S. Patent Application Publication No. 2017/0106197 A1, entitled “USER INTERFACE FOR NEUROSTIMULATION WAVEFORM COMPOSITION”, all assigned to Boston Scientific Neuromodulation Corporation, which are incorporated herein by reference in their entireties.
Threshold circuitry 964 can determine the one or more thresholds for the one or more stimulation waveforms. In various embodiments, threshold circuitry 1064 can receive one or more known values of the one or more thresholds and determine needed values of the one or more thresholds based on the received one or more known values. The one or more known values can be measured, for example, from the patient's response to delivery of neurostimulation pulses according to at least a portion of the pattern of neurostimulation pulses. Threshold circuitry 964 can determine the needed values of the one or more thresholds using the received one or more known values by executing an algorithm allowing for prediction of the needed values of the one or more thresholds based on the one or more known values. In various embodiments, the algorithm can be developed using modeling, pre-clinical data, clinical data, and/or information from literature. When the one or more thresholds relate to pulse amplitude and pulse width, the algorithm can include strength-duration curve fitting.
In various embodiments, threshold circuitry 964 can determine one or more thresholds each being a limit of a waveform parameter for one or more given values or value ranges of other one or more waveform parameters. For example, the waveform parameters can include a pulse amplitude and a pulse width, and threshold circuitry 964 can determine an amplitude threshold being a maximum value of the pulse amplitude for each given value or range of values of the pulse width. This amplitude threshold can be determined for each combination of pulse frequency, pulse shape, and stimulation field used in a stimulation program. While the amplitude threshold will be specifically discussed below as an example, threshold circuitry 964 can determine various types of thresholds for various waveform parameters. Examples of the waveform parameters related to determination of the one or more thresholds by threshold circuitry 964 can include two or more of the following:
In various embodiments, threshold circuitry 964 can determine one or more thresholds of a first parameter selected from parameters (1)-(5) for one or more given values or value ranges of one or more second parameters (each being different from the first parameter) selected from parameters (1)-(5). The first parameter may be selected because it has one or more thresholds of interest for ensuring, for example, therapeutic efficacy and/or patient tolerance. The one or more second parameters may each be selected because it can affect the one of more thresholds of the first parameter. When more than one second parameters are selected, threshold circuitry 964 can determine one or more thresholds of the first parameter for one or more given values or value ranges of one of the second parameters while holding the remaining second parameter(s) unchanged when the one or more thresholds are determined for all the interested values or value ranges for this one of the second parameters, and can repeat for each interested combination of values or value ranges of all the second parameters. For example, threshold circuitry 964 can determine one or more thresholds of the pulse amplitude for one or more given values or value ranges of the pulse width for one stimulation field at a time, and repeat until the one or more thresholds of the pulse amplitude are determined for all the stimulation fields. In some embodiments, threshold circuitry 964 can determine one or more thresholds each being a limit of the first parameter being parameter (6) for one or more given values or value ranges of the one or more second parameters selected from parameters (3)-(5).
In various embodiments, threshold circuitry 1064 can determine any type of threshold for a waveform parameter such as one of parameters (1)-(6). Examples of the one or more thresholds that can be determined for each waveform parameter by threshold circuitry 1064 can include one or more of the following:
In some embodiments, threshold circuitry 964 can determine one or more thresholds each being a worst-case limit of the first parameter for one or more worst-case values of the one or more second parameters. The “worst case” can be the worse case for the entire stimulation program or for a portion of the program. Examples for the one or more worst-case values of the one or more second parameters include the highest pulse amplitude, the longest pulse width, the highest pulse frequency, the most efficient stimulation field in producing a response in the patient, the most efficient stimulation field in producing a response in the patient, the most efficient waveform shape in producing a response in the patient, and the largest amount of pulse charge. Because determining a single worst case for an entire stimulation program or an entire pattern of neurostimulation pulses may result in overly conservative thresholds, multiple worst cases can be identified, each from a segment in the pattern of neurostimulation pulses. Threshold circuitry 964 can determine the one or more thresholds for such worst case(s) set by the one or more second parameters. In various embodiments, threshold circuitry 964 can identify such worse case(s) from the one or more stimulation waveforms defining the pattern of neurostimulation pulses and determine the one or more thresholds accordingly. In some embodiments, threshold circuitry 964 can receive user-defined worse case(s) from the user using a user interface, such as user interface 810, and determine the one or more thresholds accordingly. In some embodiments, threshold circuitry 964 can identify worse case(s) from the one or more stimulation waveforms defining the pattern of neurostimulation pulses and receive the user-defined worse case(s) from the user using the user interface, and can determine the one or more thresholds based on both the identified worst case(s) and user-defined worse case(s).
The examples for the waveform parameters and the one or more thresholds, including parameters (1)-(6) and thresholds (A) and (B) are provided for the purpose of illustration, but not for the purpose of restriction. A specific example of using threshold circuitry 964 to determine an amplitude threshold being a maximum value of the pulse amplitude for each given value or range of values of the pulse width is discussed below to illustrate, rather than restrict, how a threshold of a waveform parameter can be determined. This example can be applied for determining one or more thresholds for any waveform parameter, including but not limited to those discussed in this document, by those skilled in the art upon reading and understanding this document.
Each pulse of the pattern of neurostimulation pulses has a value of the pulse amplitude and an associated value of the pulse width. In the illustrated embodiment, threshold circuitry 1064 includes amplitude threshold circuitry 1066 to determine an amplitude threshold being a maximum value of the pulse amplitude for each given value or range of values of the pulse width. In various embodiments, amplitude threshold circuitry 1066 can determine an amplitude threshold for each stimulation field of the one or more stimulation fields associated with the pattern of neurostimulation fields.
In one embodiment, amplitude threshold circuitry 1066 determines an amplitude threshold for a range of values of the pulse width. Amplitude threshold circuitry 1066 can determine the amplitude threshold by measuring the maximum value of the pulse amplitude for a maximum value of the pulse width (e.g., a worst-case value of the pulse width) in the range of values of the pulse width. The range of values of the pulse width can include one or more values of the pulse width. The amplitude threshold can include a plurality of values each being the maximum value of the pulse amplitude for a range of the range of values of the pulse width. Amplitude threshold circuitry 1066 can determine each value of the amplitude threshold by measuring the maximum value of the pulse amplitude for a maximum value of the pulse width in each range of the range of values of the pulse width.
In one embodiment, amplitude threshold circuitry 1066 determines an amplitude threshold using a relationship between values of the pulse amplitude and values of the pulse width. The relationship allows for prediction of values of the amplitude threshold for all the needed values of the pulse width based on one or more values of the amplitude threshold measured for one or more given values of the pulse width. The relationship can be established using data collected from the patient, data collected from a patient population, data resulting from simulations with neurophysiological models, and/or date collected from literature. An example of the relationship includes a strength-duration curve. Amplitude threshold circuitry 1066 can determine each value of the amplitude threshold by measuring one or more maximum values of the pulse amplitude for one or more given values of the pulse width and calculate remaining one or more maximum values of the pulse amplitude using a relationship between the pulse amplitude and the pulse width. In one embodiment, the relationship includes a strength-duration curve. The strength-duration curve can be individually determined for the patient using information including clinical data collected from the patient. When the amplitude threshold needs to be determined for each stimulation field of the one or more stimulation fields associated with the pattern of neurostimulation pulses, the strength-duration curve can also be determined for each stimulation field. Other information such as data collected from a patient population, data resulting from simulation with a neurophysiological model, and/or information from literature may also be used in the determination of the strength-duration curves.
For the purpose of illustration but not restriction, 4 pairs of known values of the pulse amplitude and the pulse width are shown, including (PW1, AMP1), (PW2, AMP2), (PW3, AMP3), and (PW4, AMP4). In various embodiments, any one or more pairs may be required, and in some embodiments, pairs beyond the required may also be used for additional accuracy, for example. In various embodiments, the values of the pulse width are given, and the value of the pulse amplitude can be made known, for example, by measurement performed on the patient. In the illustrated example, the “PROGRAMMABLE PW RANGE” represents the range of values or the pulse width that may be used in the one or more stimulation waveforms, with PW1 being the minimum value and PW2 being the maximum value. PW3 and PW4 are values that may be arbitrarily chosen or evenly distributed between PW1 and PW2. In various embodiments, one or more AMP-PW pairs may be used for determining the needed values for the amplitude threshold. In one embodiment, one pair such as any of the four illustrated pairs may be required. In another embodiment, two pairs such as the illustrated (PW1, AMP1) and (PW2, AMP2) may be required. In one embodiment, the user may enter as many pairs as desirable when many values of the amplitude threshold are known.
At 1410, one or more thresholds are determined. The one or more thresholds are each a limit for a parameter of waveform parameters defining one or more stimulation waveforms. Examples for the waveform parameters include parameters (1)-(6) as discussed above, and examples for the one or more thresholds include thresholds (A) and (B) as discussed above. The determination includes receiving one or more known values of one or more thresholds at 1411 and determining needed values of the one or more thresholds at 1412.
At 1411, the one or more known values of one or more thresholds are received. In various embodiments, the one or more known values of one or more thresholds can be obtained by measuring from the patient. At 1412, the needed values of the one or more thresholds are determined by executing an algorithm allowing for prediction of the needed values of the one or more thresholds based on the one or more known values.
At 1420, the one or more stimulation waveforms are determined using constraints including the determined one or more thresholds. In various embodiments, the constraints are applied to ensure safety and/or comfort of the patient. For example, the one or more thresholds can be used to prevent intolerable pain and/or other discomfort from being caused by the neurostimulation. In various embodiment, one or more stimulation fields are determined. The one or more stimulation fields are each defined by a set of active electrodes through which one or more neurostimulation pulses will be delivered to the patient. The one or more threshold can be determined for each of the one or more stimulation fields. This means receiving the one or more known values of one or more thresholds and determining the needed values of the one or more thresholds for each stimulation field. In various embodiment, the one or more stimulation fields are each further defined by a fractionalization assigning a fraction of the overall current amplitude of a neurostimulation pulse to each electrode of the set of active electrodes. Different stimulation fields can include stimulation fields that have the same set of active electrodes but different fractionalizations.
At 1430, a pattern of neurostimulation pulses is determined. In various embodiments, the pattern of neurostimulation pulses can include the one or more stimulation waveforms. Stimulation field may not be needed for defining the pattern of neurostimulation pulses when the electrode configuration including fractionalization does not change during the delivery of the neurostimulation according to the pattern of neurostimulation pulses. In various embodiments, the pattern of neurostimulation pulses can include the one or more stimulation waveforms and the one or more stimulation fields.
At 1440, the stimulation device is programmed for delivering the neurostimulation according to the determined pattern of neurostimulation pulses. This can include determining stimulation parameters used by the stimulation device to control the delivery based on the pattern of neurostimulation pulses, and transmitting the stimulation parameters to the stimulation device.
In various embodiments, waveform parameters defining the one or more stimulation parameters can include a pulse amplitude and a pulse width. The one or more thresholds can include an amplitude threshold being a maximum value of the pulse amplitude for each given value or range of values of the pulse width. In one embodiment, the amplitude threshold can be determined as the maximum value of the pulse amplitude for a maximum value of the pulse width in each given range of values of the pulse width. In one embodiment, the amplitude threshold can be determined by determining needed values of the amplitude threshold using one or more known values of the amplitude threshold and a relationship between the pulse amplitude and the pulse width. One example of such a relationship includes a strength-duration curve. The strength-duration curve can be determined for each of the one or more stimulation fields using information including data collected from the patient.
It is to be understood that the above detailed description is intended to be illustrative, and not restrictive. Other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
This application is a continuation of U.S. application Ser. No. 16/151,083, filed Oct. 3, 2018, which claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No. 62/583,104, filed on Nov. 8, 2017, each of which are herein incorporated by reference in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| 62583104 | Nov 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16151083 | Oct 2018 | US |
| Child | 17706309 | US |
