System for controlling therapy control parameter update

Abstract

To provide a system for providing therapy to a patient.SOLUTION: A system of the present invention can include a therapy output device for providing therapy and a therapy control circuit for controlling provision of therapy using a detected therapy control signal. The therapy control circuit can include a therapy controller for providing therapy using therapy parameters, a therapy parameter adjuster for adjusting therapy parameters using one or two or more detected input parameters, a physiological state detector for detecting the physiological state of a patient using one or two or more physiological signals of detected therapy control signals that have been received, a measurement system for measuring one or two or more signals of the detected therapy control signals at a detection update rate, and generating one or two or more detected input parameters on the basis of the measurement, and an update rate adjuster for adjusting the detection update rate on the basis of one or two or more rate adjusting parameters including the detected physiological state.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] [Claim of priority] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 63 / 109,483, filed November 4, 2020, which is incorporated by reference in its entirety.

[0002] This document relates generally to medical devices, and more particularly to medical devices that modify parameter update rates with closed-loop control for efficient use of power and computational resources. [Background technology]

[0003] Neurostimulation (also called neuromodulation) has been proposed as a treatment for many disorders. Examples of neurostimulation include spinal cord stimulation (SCS), deep brain stimulation (DBS), peripheral nerve stimulation (PNS), and functional electrical stimulation (FES). To provide such treatment, implantable neurostimulation systems have been applied. An implantable neurostimulation system may include an implantable neurostimulator, also called an implantable pulse generator (IPG), and one or more implantable leads, each of which includes one or more electrodes. The implantable neurostimulator delivers neurostimulation energy through one or more electrodes placed at or near a target site in the nervous system. An external programming device is used to program the implantable neurostimulator with stimulation parameters that control the delivery of the neurostimulation energy.

[0004] In one example, neurostimulation energy is delivered in the form of electrical signals. This delivery is controlled using stimulation parameters that specify the spatial (where to stimulate), temporal (when to stimulate), and informational (stimulation pattern that will cause the nervous system to respond in a desired way) aspects of the electrical signal pattern. Determining these stimulation parameters according to the patient's condition and treatment objectives can improve the effectiveness and efficiency of a particular neurostimulation treatment and reduce its side effects. Although modern electronics can meet the need to generate advanced signal patterns, the capabilities of a neurostimulation system depend on how the stimulation parameters that define such signal patterns can be determined and tailored for a patient to ensure the effectiveness and efficiency of these stimulation treatments when applying neurostimulation to the patient. Summary of the Invention [Means for solving the problem]

[0005] An example of a system for providing therapy to a patient (e.g., "Example 1") can include a therapy output device and a therapy control circuit. The therapy output device can be configured to provide therapy to the patient. The therapy control circuit is configured to receive a sensed therapy control signal and control the delivery of therapy using the received sensed therapy control signal. The therapy control circuit can include a therapy controller, a therapy parameter adjuster, a physiological condition detector, a measurement system, and an update rate adjuster. The therapy controller can be configured to control the delivery of therapy using the therapy parameter. The therapy parameter adjuster can be configured to adjust the therapy parameter using one or more sensed input parameters. The physiological condition detector can be configured to detect a physiological condition of the patient using one or more of the sensed physiological signals of the received sensed therapy control signal. The measurement system can be configured to measure one or more of the sensed physiological signals of the received sensed therapy control signal at a sensed update rate and generate one or more sensed input parameters based on the measurement. The update rate adjuster can be configured to adjust the sensed update rate based on one or more rate adjustment parameters including the sensed physiological condition.

[0006] In Example 2, the subject matter of Example 1 can optionally be configured to include an implantable medical device including a therapy output device and a therapy control circuit.

[0007] In Example 3, the subject matter of any one or any combination of Examples 1 and 2 can optionally be configured such that the therapy output device includes a stimulation output circuit configured to deliver neurostimulation to the patient, and the therapy control circuit includes a stimulation control circuit configured to receive a detected therapy control signal and to control the delivery of the neurostimulation using the received detected therapy control signal.

[0008] In Example 4, the subject matter of any one or any combination of Examples 1 to 3 can optionally be configured such that the update rate adjuster is configured to adjust the sensing update rate based on the detected physiological condition and one or more parameters quantitatively indicative of at least one of energy or computational resources available to the therapy control circuitry.

[0009] In Example 5, the subject matter of Example 4 can optionally be configured such that the therapy control circuitry includes a main processor and a co-processor. The main processor includes a therapy controller and a therapy parameter adjuster. The co-processor includes a physiological condition detector, a measurement system, and an update rate adjuster.

[0010] In Example 6, the subject matter of Example 5 can optionally be configured to further include the power source and wherein the update rate adjuster is configured to adjust the sensed update rate based on the detected physiological condition and at least one of a battery state, a main processor state, or a coprocessor state. The battery state is a measure of remaining energy of the power source. The main processor state is a measure of a level of computational activity in the main processor. The coprocessor state is a measure of a level of computational activity in the coprocessor.

[0011] In Example 7, the subject matter of any one or any combination of Examples 1 to 6 can optionally be configured such that the therapy parameter adjuster is configured to determine the therapy parameters using the one or more sensed input parameters at a therapy update rate, and the update rate adjuster is configured to adjust the sensing update rate and the therapy update rate based on one or more rate adjustment parameters including a detected physiological condition.

[0012] In Example 8, the subject matter of Example 7 can optionally be configured such that the sensing update rate and the therapy update rate comprise a common rate.

[0013] In Example 9, the subject matter of Example 7 can optionally be configured such that the sensing update rate differs from the therapy update rate.

[0014] In Example 10, the subject matter of any one or any combination of Examples 1-9 can optionally be configured such that the physiological condition detector includes an activity level detector configured to detect an activity level as the physiological condition using one or more activity signals of the received sensed therapy control signals, and the update rate adjuster is configured to adjust the sensing update rate based on one or more rate adjustment parameters including the detected activity level, wherein the activity level is a measure of a physical activity level of the patient.

[0015] In Example 11, the subject matter of Example 10 can optionally be configured to further include a sensor configured to be communicatively coupled to the treatment control circuitry, the sensor including one or more activity sensors configured to detect one or more activity signals.

[0016] In Example 12, the subject matter of Example 11 can optionally be configured such that the activity level detector is configured to detect the activity level using a single activity signal among the received sensed therapy control signals.

[0017] In Example 13, the subject matter of Example 11 can optionally be configured such that the activity level detector is configured to detect the activity level using a plurality of activity signals among the received sensed therapy control signals.

[0018] In Example 14, the subject matter of any one or any combination of Examples 1 to 13 may optionally be configured such that the update rate adjuster is configured to adjust the sensing update rate according to a relationship relating the sensing update rate to one or more rate adjustment parameters.

[0019] In Example 15, the subject matter of Example 14 can optionally be configured such that the update rate adjuster is configured to adjust the sensing update rate using a lookup table representing the above relationship.

[0020] Also provided is an example method (e.g., "Example 16") of providing therapy to a patient. The method can include providing therapy to a patient from a therapy output device and controlling the delivery of therapy using a therapy control circuit using a therapy parameter. The controlling includes receiving sensed therapy control signals, measuring one or more of the sensed therapy control signals at a sensed update rate, generating one or more sensed input parameters based on the measuring, sensing a physiological condition of the patient using one or more of the received sensed therapy control signals, adjusting the sensed update rate based on one or more rate adjustment parameters including the sensed physiological condition, and adjusting the therapy parameter using the one or more sensed input parameters.

[0021] In Example 17, the subject matter providing therapy from a therapy output device found in Example 16 can optionally include delivering neurostimulation from a stimulation output circuit of an implantable neurostimulator, and the subject matter controlling the provision of therapy using a therapy control circuit using therapy parameters found in Example 16 can optionally include controlling the delivery of neurostimulation using a stimulation control circuit of an implantable neurostimulator using the stimulation parameters.

[0022] In Example 18, the subject matter of adjusting the sensing update rate found in any one or any combination of Examples 16 and 17 can optionally include adjusting the sensing update rate based on a detected physiological condition and one or more parameters that quantitatively indicate at least one of energy or computational resources available in the implantable neurostimulator.

[0023] In Example 19, the subject matter of adjusting a therapy parameter found in any one or any combination of Examples 16-18 can optionally include determining the therapy parameter using one or more sensed input parameters at a therapy update rate, and the subject matter of any one or any combination of Examples 16-18 can further optionally include adjusting the sensing update rate and the therapy update rate based on one or more rate adjustment parameters including a sensed physiological condition.

[0024] In Example 20, the subject matter of Example 19 can optionally include wherein the sensing update rate and the therapy update rate comprise a common rate.

[0025] In Example 21, the subject matter of any one or any combination of Examples 19 and 20 can optionally further include adjusting the sensing update rate and the therapy update rate according to a relationship relating each of the sensing update rate and the therapy update rate to one or more rate adjustment parameters.

[0026] In Example 22, the subject matter detecting a physiological condition of a patient as found in any one or any combination of Examples 16 to 21 can optionally include detecting an activity level as a physiological condition using one or more activity signals of the received sensed therapy control signals, and the subject matter adjusting a sensing update rate as found in any one or any combination of Examples 16 to 21 can optionally include adjusting a sensing update rate based on one or more rate adjustment parameters including the detected activity level, the activity level being a measure of a physical activity level of the patient.

[0027] In Example 23, the subject matter of the viewing modes found in Example 22 can optionally further include detecting one or more activity signals using one or more accelerometers.

[0028] In Example 24, the subject matter of detecting a physiological condition of a patient as found in any one or any combination of Examples 16 to 23 can optionally include detecting one or more electrophysiological signals among the detected therapy control signals.

[0029] Also provided is an example of a non-transitory computer-readable storage medium (e.g., "Example 25") that includes instructions that, when executed by the system, cause the system to perform a method for providing therapy to a patient. The method can include providing therapy to a patient from a therapy output device and controlling the delivery of therapy using a therapy control circuit using a therapy parameter. The controlling includes receiving sensed therapy control signals, measuring one or more of the sensed therapy control signals at a sensed update rate, generating one or more sensed input parameters based on the measuring, sensing a physiological condition of the patient using one or more of the received sensed therapy control signals, adjusting the sensed update rate based on one or more rate adjustment parameters that include the sensed physiological condition, and adjusting the therapy parameter using the one or more sensed input parameters.

[0030] In Example 26, the subject matter of Example 25 can be configured such that detecting the patient's physiological condition includes detecting an activity level as a physiological condition using one or more activity signals of the received detected therapy control signals, the activity level being a measure of the patient's physical activity level, and the subject matter of adjusting the sensing update rate found in Example 25 can further optionally include adjusting the sensing update rate based on one or more rate adjustment parameters including the detected activity level.

[0031] This summary summarizes some of the teachings of the present application and is not intended to be an exclusive or comprehensive treatment of the present subject matter. Further details regarding the present subject matter are found in the detailed description and the appended claims. Other aspects of the present disclosure will become apparent to those skilled in the art upon reading and understanding the following detailed description and the drawings that form a part thereof, each of which should not be taken in a limiting sense. The scope of the present disclosure is defined by the appended claims and their legal equivalents.

[0032] The drawings illustrate generally, by way of example, various embodiments discussed in the present document. The drawings are for illustrative purposes and may not be to scale. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 illustrates an embodiment of a neurostimulation system. [Diagram 2] FIG. 2 illustrates an embodiment of a stimulator and lead system that may be implemented in the neurostimulation system of FIG. 1. [Diagram 3] FIG. 2 illustrates an embodiment of a programming device that may be implemented in the neurostimulation system of FIG. 1. [Figure 4] FIG. 3 illustrates an embodiment of an implantable pulse generator (IPG) and an implantable lead system, such as an implementation of the stimulator and lead system of FIG. [Diagram 5] FIG. 5 illustrates an embodiment of an IPG and implantable lead system positioned to provide neurostimulation to a patient, such as the IPG and lead system of FIG. [Figure 6] FIG. 1 illustrates an embodiment of some of the neurostimulation systems. [Figure 7] 7A-7C illustrate an embodiment of an implantable stimulator and one or more leads of an implantable neurostimulation system, such as the implantable neurostimulation system of FIG. [Figure 8] FIG. 7 illustrates an embodiment of an external programmer for an implantable neurostimulation system, such as the implantable neurostimulation system of FIG. [Figure 9]FIG. 1 illustrates an embodiment of a sensor and therapy device that provides therapy to a patient and controls the delivery of therapy using sensed therapy control signals. [Figure 10] FIG. 10 illustrates an embodiment of a system including a therapy output device and therapy control circuitry, as implemented in the therapy device of FIG. [Figure 11] 8 illustrates an embodiment of an implantable medical device that can be configured to be an implantable stimulator, such as the implantable stimulator of FIG. 7. [Figure 12] 11 illustrates an embodiment of one or more physiological condition sensors and a physiological condition detector for detecting a patient's physiological condition in a therapy control system, such as the system of FIG. 10. [Figure 13] 11 illustrates an embodiment of an update rate adjuster that adjusts one or more parameter update rates in a therapy control system, such as the system of FIG. 10. [Figure 14] 11 illustrates an embodiment of a method of providing treatment to a patient, such as a method that can be performed by the system of FIG. 10. [Figure 15] FIG. 13 illustrates an example of parameter update rate as a function of a rate adjustment parameter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, showing by way of example specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable one skilled in the art to practice the present invention, but it should be understood that these embodiments may be combined or other embodiments may be utilized, and structural, logical, and electrical changes may be made without departing from the spirit and scope of the present invention. References to "a," "one," or "various" embodiments in this disclosure are not necessarily to the same embodiment, and such references contemplate multiple embodiments. The following detailed description is by way of example, and the scope of the present invention is defined by the appended claims and their legal equivalents.

[0035] This document describes, among other things, an implantable medical device that dynamically adjusts update frequency in closed-loop therapy control operation for efficient use of power and computational resources. For example, the implantable medical device may include a battery-powered implantable pulse generator (IPG) that performs closed-loop operation with on-board sensing and stimulation updates. The rate (i.e., frequency) at which sensing and stimulation updates are performed is a significant factor in determining the cost of operation of the closed-loop therapy control, including the cost of energy and the cost of computational resources. The IPG may be battery-powered for chronic use when placed under the patient's skin. It is desirable for the battery to have a long life and / or long time between charges, and thus conserving battery power is a design goal for the benefit of the patient. IPGs, including implantable neurostimulators, use a closed-loop sensing and stimulation system that can be sensed by one or more sensors in the IPG, implanted in the patient and communicatively coupled to the IPG, and / or carried externally by the patient or placed near the patient and communicatively coupled to the IPG, to provide therapy control in response to changes in the patient's needs and / or conditions. Operation of such a closed-loop system requires energy and places a strain on the computational resources available to the IPG. Such requirements increase with the rate at which sensing and stimulation updates are performed. Faster sensing and stimulation update rates allow for quicker therapy adjustments in response to changing patient needs and / or conditions, but consume more energy and more computational resources (which also means more energy). Thus, there is a need for sensing and stimulation update rates that allow for adequate performance of closed-loop therapy control while minimizing the energy consumption required for its operation.

[0036] The present subject matter controls the rate at which sensing and stimulation updates are performed in a closed-loop therapy control system based on a detected indicator of how quickly one or more input signals are changing. An IPG, such as an implantable neurostimulator, can be implemented with a system that controls the sensing and stimulation update rate. The therapy update rate can be adjusted based on one or more sensed signals from which an indicator can be detected. The indicator can include a patient activity level that can be detected from any one or more signals indicative of patient activity that can be detected using an implantable sensor and / or an external sensor. The therapy update rate can be increased when necessary, as indicated by a high patient activity level, and decreased when the patient activity level is low. Other factors can also be used to adjust the therapy update rate. For example, when the battery level is low, the therapy update rate can be decreased to keep the IPG operating in a power-saving mode.

[0037] In an example embodiment, the system for controlling the sensing and stimulation therapy update rate is implemented as firmware in the IPG's processor, which controls the IPG's operation at a high level, and the IPG's co-processor provides the main processor with detected indications of how quickly one or more input signals to the closed-loop therapy control system are changing. Thus, the IPG's main processor controls the therapy update rate of the closed-loop therapy control system, and the co-processor can detect the patient's activity level using signals from one or more sensors. The main processor tracks available power (battery) and computational resources in the IPG, receives data from the co-processor indicative of the patient's activity level, and can adjust the therapy update rate, such as at regular intervals, based on the patient's activity level.

[0038] Determining the sensing and stimulation therapy update rate can be an optimization process that balances the risk of inappropriate (e.g., insufficient or excessive) stimulation and the amount of power consumption and computational resources (e.g., from the main processor and co-processors) associated with the therapy update rate. The frequency of running the closed-loop therapy control algorithm, measuring one or more input signals, and adjusting the therapy (e.g., stimulation) can vary from measurement to measurement. In various embodiments, the sensing and stimulation therapy update rate can be a function of, or a rate at which, one or more input signals are measured.

[0039] Although an IPG for neurostimulation is described as an example, the present subject matter may be applied to any closed-loop therapy control system, for example to reduce power consumption and / or computational resource demands. In various embodiments, the present subject matter provides flexibility in therapy adjustment based on one or more indicators of ongoing or anticipated need for constant frequency adjustment, such as the patient's activity level and the IPG's battery status. This may enable substantial power and / or computational resource savings, for example, when compared to existing devices that use a constant sensing and stimulation therapy update rate determined to correspond to the highest patient activity level.

[0040] As used herein, a "patient" includes a person receiving treatment provided using a therapeutic system including an IPG, such as a neurostimulation system including an implantable neurostimulator according to the present subject matter, and a "user" includes a physician or other caregiver who treats a patient using the therapeutic system.

[0041] FIG. 1 illustrates an embodiment of a neurostimulation system 100. The system 100 includes an electrode 106, a stimulator 104, and a programmer 102. The electrode 106 is configured to be placed at or near one or more neural targets within a patient's body. The stimulator 104 is electrically connected to the electrode 106 and configured to deliver neurostimulation energy in the form of electrical pulses or the like to the one or more neural targets through the electrode 106. The delivery of the neurostimulation is controlled using a plurality of stimulation parameters, such as stimulation parameters that specify an electrical pulse pattern and a selection of electrodes to deliver each electrical pulse to. In various embodiments, at least some of the plurality of stimulation parameters are programmable by a user, such as a physician or other caregiver treating a patient using the system 100. The programmer 102 facilitates user access to the user-programmable parameters. In various embodiments, the programmer 102 is configured to communicatively couple to the stimulator via a wired or wireless link.

[0042] A "user" in this document includes a physician or other clinician or caregiver who treats a patient using system 100, and a "patient" includes a person who receives or is intended to receive neurostimulation delivered using system 100. In some embodiments, the patient may use system 100 to adjust their own treatment to some extent, such as by adjusting certain treatment parameters and inputting feedback and clinical effectiveness information.

[0043] In various embodiments, the programmer 102 may include a user interface 110 that allows a user to control the operation of the system 100 and monitor the performance of the system 100 and the condition of the patient, including the response to the delivery of neurostimulation. The user may control the operation of the system 100 by setting and / or adjusting values ​​of user-programmable parameters.

[0044] In various embodiments, the user interface 110 can include a graphical user interface (GUI) that allows a user to set and / or adjust values ​​of user-programmable parameters by creating and / or editing graphical representations of various waveforms. Such waveforms can include waveforms that represent patterns of neural stimulation pulses to be delivered to a patient, and individual waveforms that are used as building blocks for patterns of neural stimulation pulses, such as the waveforms of each pulse in a pattern of neural stimulation pulses. The GUI can allow a user to set and / or adjust stimulation fields, each defined by a set of electrodes that enables one or more neural stimulation pulses represented by a waveform to be delivered to a patient. Each stimulation field can be further defined by a distribution of current for each neural stimulation pulse within the waveform. In various embodiments, neural stimulation pulses over a stimulation period (such as the duration of a treatment session) can be delivered to multiple stimulation fields.

[0045] 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 neurostimulation operations of the system 100. For example, the system 100 and user interface 110 can be configured for DBS applications. Such DBS configurations include various features, such as those described herein, that can simplify a user's task in programming the stimulator 104 to deliver DBS to a patient.

[0046] FIG. 2 illustrates an embodiment of a stimulator 204 and a lead system 208 that may be implemented in the neurostimulation system 100. The stimulator 204 represents one example of the stimulator 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 controls the delivery of the neural stimulation pulses from the stimulation output circuit 212 using a number of stimulation parameters that specify a neural stimulation pulse pattern. The lead system 208 includes one or more leads, each configured to be electrically connected to the stimulator 204, and a number of electrodes 206 distributed on the one or more leads. The number of electrodes 206 includes electrodes 206-1, 206-2, . . . , 206-N, where N≧2, each of which is a single conductive contact that provides an electrical interface between the stimulation output circuit 212 and the patient's tissue. The neural stimulation pulses are delivered from the stimulation output circuit 212 through a series of electrodes selected from the electrodes 206. In various embodiments, the neural stimulation pulses can include one or more individually defined pulses, and the user can individually define electrode sets for each individually defined pulse, or for each group of pulses intended to be delivered using the same electrode combination. In various embodiments, one or more additional electrodes 207 (each of which can be referred to as a reference electrode), such as one or more electrodes that are part of or otherwise incorporated into the housing of the stimulator 204, can be electrically connected to the stimulator 204. Monopolar stimulation uses a monopolar electrode configuration that includes one or more electrodes selected from the electrodes 206 and at least one electrode from the electrodes 207. Bipolar stimulation uses a bipolar electrode configuration that includes two electrodes selected from the electrodes 206 and does not include the electrode 207. Multipolar stimulation uses a multipolar electrode configuration that includes multiple (two or more) electrodes selected from the electrodes 206 and does not include the electrode 207.

[0047] In various embodiments, the number of leads and the number of electrodes on each lead depends, for example, on the distribution of the neurostimulation target(s) and the need to control the distribution of the electric field at each target. In one embodiment, the lead system 208 includes two leads, each with eight electrodes.

[0048] FIG. 3 illustrates an embodiment of a programming device 302 that may be implemented in the neurostimulation system 100. The programming device 302 represents an example of the programming device 102 and includes a memory 318, a programming control circuit 316, and a user interface 310. The programming control circuit 316 generates a number of stimulation parameters that control the delivery of neural stimulation pulses according to a specified neural stimulation program that may define, for example, a stimulation waveform and an electrode configuration. The user interface 310 represents an example of the user interface 110 and includes a stimulation control circuit 320. The memory 318 stores information used by the programming control circuit 316 and the stimulation control circuit 320, such as information about the stimulator that associates the neural stimulation program with a number of stimulation parameters. In various embodiments, the stimulation control circuit 320 can be configured to support one or more functions that enable programming of a stimulator, such as the stimulator 104, including various embodiments as described herein, according to one or more selected neural stimulation programs as described herein.

[0049] In various embodiments, the user interface 310 may enable the definition of a pattern of neural stimulation pulses to be delivered during a neural stimulation therapy session by creating and / or adjusting one or more stimulation waveforms using a graphical method. This definition may also include the definition of one or more stimulation fields, each associated with one or more pulses of the pattern of neural stimulation pulses. As used herein, a "neural stimulation program" may include a pattern of neural stimulation pulses including one or more stimulation fields, or at least various aspects or parameters of a pattern of neural stimulation pulses including one or more stimulation fields. In various embodiments, the user interface 310 includes a GUI that enables a user to define a pattern of neural stimulation pulses and perform other functions using a graphical method. In this document, "neural stimulation programming" may include the definition of one or more stimulation waveforms, including the definition of one or more stimulation fields.

[0050] In various embodiments, the circuitry of the neurostimulator 100, including the various embodiments described herein, can be implemented using a combination of hardware and software. For example, the circuitry of the user interface 100, the stimulation control circuit 214, the programming control circuit 316, and the stimulation control circuit 320, including the various embodiments described herein, can be implemented using application specific circuitry configured to perform one or more specific functions, or general purpose circuitry programmed to perform such function(s). Such general purpose circuitry includes, but is not limited to, a microprocessor or portion thereof, a microcontroller or portion thereof, and a programmable logic circuit or portion thereof.

[0051] FIG. 4 illustrates an embodiment of an implantable pulse generator (IPG) 404 and an implantable lead system 408. The IPG 404 represents an implementation of the stimulator 204. The lead system 408 represents an implementation of the lead system 208. As shown in FIG. 4, the IPG 404 can be coupled to implantable leads 408A and 408B at their proximal ends. The distal end of each lead includes an electrical contact or electrode 406 that contacts a tissue site that is the target of electrical neurostimulation. As shown in FIG. 1, the leads 408A and 408B each include eight electrodes 406 at their distal ends. The leads 408A and 408B and the number and arrangement of the electrodes 406 as shown in FIG. 1 are exemplary only, and other numbers and arrangements are possible. In various embodiments, the electrodes are ring electrodes. The implantable leads and electrodes can be configured in a shape and size to provide electrical neurostimulation energy to a neuronal target contained in the brain of the subject or to provide electrical neurostimulation energy to a neuronal target contained in the spinal cord of the subject.

[0052] Figure 5 illustrates an implantable neurostimulation system 500 and some of the environments in which system 500 may be used. System 500 includes an implantable system 521, an external system 502, and a telemetry link 540 that provides wireless communication between implantable system 521 and external system 502. In Figure 5, implantable system 521 is shown implanted within a patient's body 599.

[0053] The implantable system 521 includes an implantable stimulator 504 (also called an implantable pulse generator or IPG), a lead system 508, and electrodes 506, which represent examples of the stimulator 204, lead system 208, and electrodes 206, respectively. The external system 502 represents an example of a programmer 302. In various embodiments, the external system 502 includes one or more external (non-implantable) devices, each of which enables communication between a user and / or patient and the implantable system 521. In some embodiments, the external system 502 includes a programmer intended for a user to initialize and adjust settings of the implantable stimulator 504, and a remote control intended for use by a patient. For example, the remote control may enable a patient to turn the implantable stimulator 504 on and off and / or adjust certain patient-programmable parameters of a plurality of stimulation parameters.

[0054] The size and shape of the elements of the implantable system 521 and their location within the body 599 are provided by way of example and not by way of limitation. An implantable system is described as a particular application of programming in accordance with various embodiments of the present subject matter. In various embodiments, the present subject matter can be applied to programming stimulation targets within a patient's body and any type of stimulator that uses electrical pulses as stimulation, whether the stimulator is implantable or not.

[0055] Referring again to FIG. 4 , the IPG 404 can include a sealed IPG case 422 that houses the electronic circuitry of the IPG 404. The IPG 404 can include an electrode 426 formed on the IPG case 422. The IPG 404 can include an IPG header 424 that couples the proximal ends of the leads 408A and 408B. The IPG header 424 can also optionally include an electrode 428. The electrodes 426 and / or 428 represent embodiments of the electrodes 207, and each can be referred to as a reference electrode. The neurostimulation energy can be delivered in a monopolar mode (also referred to as unipolar) using the electrode 426 or the electrode 428 and one or more electrodes selected from the electrodes 406. The neurostimulation energy can also be delivered in a bipolar mode using a pair of electrodes on the same lead (lead 408A or lead 408B). Neurostimulation energy can also be delivered in an extended bipolar mode using one or more electrodes on a lead (e.g., one or more electrodes on lead 408A) and one or more electrodes on a different lead (e.g., one or more electrodes on lead 408B).

[0056] The electronic circuitry of the IPG404 may include control circuitry that controls the delivery of neurostimulation energy. The control circuitry may include a microprocessor, digital signal processor, application specific integrated circuit (ASIC), or other type of processor that interprets or executes instructions contained in software or firmware. The neurostimulation energy may be delivered according to specified (e.g., programmed) modulation parameters. Examples of setting modulation parameters include, among others, selecting an electrode or combination of electrodes to use in stimulation, configuring one or more electrodes as an anode or cathode for stimulation, specifying the percentage of neurostimulation provided by an electrode or combination of electrodes, and specifying stimulation pulse parameters. Examples of pulse parameters include, among others, pulse amplitude (specified in current or voltage), pulse duration (e.g., in microseconds), pulse rate (e.g., in pulses / second), and parameters related to a pulse train or pattern such as burst rate (e.g., "off" modulation time after "on" modulation time), amplitude of a pulse within a pulse train, and polarity of the pulse.

[0057] 6 illustrates an embodiment of some of the neurostimulation systems 600. The system 600 includes an IPG 604, implanted neurostimulation leads 608A and / or 608B, an external remote control (RC) 632, a clinician programmer (CP) 630, and an external test stimulator (ETS) 634 (also referred to as an external test modulator or ETM). The IPG 404 can be electrically coupled to the leads 608A and 608B directly or through a percutaneous extension lead 636. The ETS 634 can be electrically connectable to the leads 608A and 608B via one or both of the percutaneous extension lead 636 and / or an external cable 638. The system 600 represents one example of the system 100, in which the IPG 604 represents an embodiment of the stimulator 104, the electrodes 606 of the leads 608A and 608B represent the electrodes 106, and the CP 630, RC 632, and ETS 634 collectively represent the programmer 102.

[0058] The ETS 634 can be standalone or integrated into the CP 630. The ETS 634 can have pulse generation circuitry similar to the IPG 604 that delivers neurostimulation energy according to specified modulation parameters as described above. The ETS 634 is an external device that is typically used as a pre-stimulator after the leads 408A and 408B are implanted and prior to stimulation with the IPG 604 to test the patient's responsiveness to the stimulation provided by the IPG 604. Because the ETS 634 is external, it can be more easily configurable than the IPG 604.

[0059] The CP 630 can configure the neurostimulation provided by the ETS 634. If the ETS 634 is not integrated into the CP 630, the CP 630 can communicate with the ETS 634 using a wired connection (e.g., via a USB link) or by wireless communication link 640 using wireless telemetry. The CP 630 also communicates with the IPG 604 using wireless communication link 640.

[0060] An example of wireless telemetry is based on inductive coupling using mutual inductance between two closely placed coils. This type of telemetry is usually called inductive telemetry or near-field telemetry because the coils must be in close proximity to obtain inductively coupled communication. The IPG 604 can include a first coil and communication circuitry. The CP 630 can include a second coil in the form of a wand or the like that can be placed near the IPG 604 or can be otherwise electrically connected to such a second coil. Another example of wireless telemetry includes a far-field telemetry link, also called a radio frequency (RF) telemetry link. The far-field, also called the Fraunhofer zone, refers to the zone where components of the electromagnetic field generated by a transmitting electromagnetic radiation source decay substantially proportional 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 transmitted electromagnetic energy. In one example, the communication range of the RF telemetry link is at least 6 feet, but can be as long as the particular communication technology allows. For example, an RF antenna can be included in the header of the IPG604 and / or the housing of the CP630, eliminating the need for a wand or other inductive coupling means. An example of such an RF telemetry link is a Bluetooth® wireless link.

[0061] The CP630 can be used to set modulation parameters for the neurostimulation after the IPG604 is implanted, allowing the neurostimulation to be adjusted if neurostimulation requirements change after implantation. The CP630 can also upload information from the IPG604.

[0062] 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 less programmability compared to the CP 630. This allows the user or patient to modify the neural stimulation therapy, but does not allow the patient to fully control the therapy. For example, the patient can increase the amplitude of the neural stimulation pulses or change the application time of a preprogrammed stimulation pulse train. 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 RC 632 can be programmed when the CP 630 is located remotely from the RC 632.

[0063] 7 illustrates an embodiment of an implantable stimulator 704 and one or more leads 708 of an implantable neurostimulation system, such as implantable system 600. The implantable stimulator 704 represents an example of a stimulator 104 or 204 and may be implemented, for example, as an IPG 604. The lead(s) 708 represent an example of a lead system 208 and may be implemented, for example, as implantable leads 608A and 608B. The electrode 706 included in the lead(s) 708 represents an example of an electrode 106 or 206 and may be implemented as an electrode 606.

[0064] The implantable stimulator 704 may include optional sensing circuitry 742, which is required only if the stimulator requires sensing capabilities, stimulation output circuit 212, stimulation control circuit 714, implant memory 746, implant telemetry circuit 744, power source 748, and one or more electrodes 707. If included and required, sensing circuit 742 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 signals and other signals, each of which is indicative of a patient condition being treated by the neurostimulation and / or a patient response to delivery of the neurostimulation. The stimulation output circuit 212 is electrically connected to the electrodes 706 through one or more leads 708 as well as the electrodes 707, and delivers each of the neural stimulation pulses through a selected set of electrodes from the electrodes 706 and the electrode(s) 707. The stimulation control circuit 714 represents an example of the stimulation control circuit 214 and controls the delivery of the neural stimulation pulses using a number of stimulation parameters that specify a pattern of the neural stimulation pulses. In one embodiment, the stimulation control circuit 714 controls the delivery of the neural stimulation pulses using one or more sensed physiological signals. The implant telemetry circuit 744 provides the implantable stimulator 704 with wireless communication with another device, including receiving values ​​of a number of stimulation parameters from another device, such as the CP630 and the RC632. The implant memory device 746 can store one or more neural stimulation programs and values ​​of a number of stimulation parameters for each of the one or more neural stimulation programs. The power source 748 provides the implantable stimulator 704 with energy for operation. In one embodiment, the power source 748 includes a battery. In one embodiment, the power source 748 includes a rechargeable battery and a battery charging circuit for charging the rechargeable battery. The implant telemetry circuit 744 can also function as a power receiver that receives power transmitted from an external device through inductive coupling. The electrode(s) 707 allow for delivery of neural stimulation pulses in a unipolar mode. Examples of the electrode(s) 707 include electrode 426 and electrode 418 in the IPG 404 as shown in FIG.

[0065] In one embodiment, the implantable stimulator 704 is used as a master database. Thus, a patient implanted with an implantable stimulator 704 (as may be implemented as an IPG 604) can retain necessary patient information for their medical care when such information is otherwise unavailable. The implant storage device 746 is configured to store such patient information. For example, a patient may be given a new RC 632 and / or move to a new clinic where they may use a new CP 630 to communicate with their implanted device. The new RC 632 and / or CP 630 may communicate with the implantable stimulator 704 to retrieve the patient information stored in the implant storage device 746 via the implant telemetry circuit 744 and wireless communication link 640, and enable any necessary adjustments of the operation of the implantable stimulator 704 based on the retrieved patient information. In various embodiments, the patient information stored in the implant memory 746 can include, for example, the location of the lead(s) 708 and electrodes 706 relative to the patient's anatomy (transformation of post-operative lead placement computed tomography (CT) fused to brain magnetic resonance image (MRI)), clinical efficacy map data, objective measurements using quantitative assessments of symptoms (e.g., using microelectrode recordings, accelerometers and / or other sensors), and / or any other information deemed important or useful for providing appropriate care to the patient, etc. In various embodiments, the patient information stored in the implant memory 746 can include data transmitted to the implantable stimulator 704 for storage as part of the patient information, and data acquired by the implantable stimulator 704 using the sensing circuitry 742, etc.

[0066] In various embodiments, the sensing circuitry 742 (if included), stimulation output circuitry 212, stimulation control circuitry 714, implant telemetry circuitry 744, implant memory 746, and power source 748 are enclosed in a hermetically sealed implantable housing or case on which electrode(s) 707 are formed or otherwise incorporated. In various embodiments, the implantable stimulator 704 is implanted subcutaneously, while the electrodes 706 are positioned on and / or around one or more targets to which neural stimulation pulses are to be delivered, and the lead(s) 708 are implanted such that they are connected to the lead(s) 708 upon implantation.

[0067] 8 shows an embodiment of an external programmer 802 for an implantable neurostimulation system, such as system 600. The external programmer 802 represents an example of a programmer 102 or 302 and may be implemented, for example, as a CP 630 and / or an RC 632. The external programmer 802 includes an external telemetry circuit 852, an external memory device 818, a programming control circuit 816, and a user interface 810.

[0068] The external telemetry circuit 852 provides the external programmer 802 with wireless communication with another device, such as the implantable stimulator 704, via wireless communication link 640, including transmitting 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 through inductive coupling.

[0069] In various embodiments, the wireless communication link 640 can include an inductive telemetry link (near-field telemetry link) and / or a far-field telemetry link (RF telemetry link). For example, because DBS is often used for movement disorders that are assessed through the patient's activity, gait, balance, etc., it is useful to allow patient mobility during programming and evaluation. Thus, when the system 600 is intended for applications involving DBS, the wireless communication link 640 includes at least a far-field telemetry link that allows communication between the external programmer 802 and the implanted stimulator 704 over relatively long distances, such as up to about 20 meters. Each of the external telemetry circuit 852 and the implant telemetry circuit 744 includes an antenna and RF circuitry configured to support such wireless telemetry.

[0070] The external storage device 818 stores one or more stimulation waveforms delivered during a neural stimulation therapy session, such as a DBS therapy session, as well as various parameters and building blocks that define the one or more waveforms. Each of the one or more stimulation waveforms is associated with one or more stimulation fields and can represent a pattern of neural stimulation pulses to be delivered to the one or more stimulation fields during a neural stimulation therapy session. In various embodiments, each of the one or more stimulation waveforms can be selected for modification by a user and / or for use in programming a stimulator, such as the implantable stimulator 704, to provide therapy. In various embodiments, each waveform of the one or more stimulation waveforms is definable for each pulse, and the external storage device 818 can include a pulse library that stores one or more individually definable pulse waveforms, each of which defines one or more pulse types. The external storage device 818 also stores one or more individually definable stimulation fields. Each waveform of the one or more stimulation waveforms is associated with at least one of the one or more individually definable stimulation fields. Each of the one or more individually definable stimulation fields is defined by an electrode set that delivers a neural stimulation pulse. In various embodiments, each of the one or more individually definable stimulation fields is defined by an electrode set that delivers a neural stimulation pulse and a current distribution of the neural stimulation pulse on the electrode set. In one embodiment, the current distribution is defined by assigning a portion of the overall pulse amplitude to each electrode of the electrode set. In this document, such a definition of the current distribution can be referred to as "fractionalization". In another embodiment, the current distribution is defined by assigning an amplitude value to each electrode of the electrode set. For example, an electrode set can include two electrodes used as anodes and an electrode used as cathodes to deliver a neural stimulation pulse with a pulse amplitude of 4 mA. It is necessary to define the current distribution across the two electrodes used as anodes. For example, a percentage of the pulse amplitude is assigned to each of the two electrodes, such as 75% to electrode 1 and 25% to electrode 2. In another embodiment, an amplitude value is assigned to each of the two electrodes, such as 3 mA to electrode 1 and 1 mA to electrode 2.By controlling the current in percentage units, the current between the electrodes can be distributed accurately and consistently even as the pulse amplitude is adjusted. This suits thinking of the problem as steering the stimulation locus, varying stimulation on multiple contacts simultaneously to move this locus while keeping the amount of stimulation constant. By controlling and displaying the total current through each electrode in absolute units (e.g., mA), the current can be precisely dosed through each specific electrode. This suits (allows the user to) vary the current on one contact at a time to mold the stimulation like a piece of clay (pushing / pulling one area at a time).

[0071] The programming control circuit 816 represents one example of the programming control circuit 316 and generates a number 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, or at least some aspects of the pattern, represented by one or more stimulation waveforms and one or more stimulation fields). The neural stimulation program may 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 may check values ​​of the plurality of stimulation parameters against safety rules to limit the values ​​within limits of the safety rules. In one embodiment, the safety rules are heuristic rules.

[0072] User interface 810 represents one 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 can include any type of interactive or non-interactive screen, and user input device 858 can include any type of user input device that supports the various functions described herein, such as a touch screen, keyboard, keypad, touchpad, trackball, joystick, mouse, etc. In one embodiment, user interface 810 includes a GUI. The GUI can also enable a user to perform any of the functions described herein suitable for graphical presentation and / or editing, as will be appreciated by those skilled in the art.

[0073] The interface control circuitry 854 controls the operation of the user interface 810, including defining one or more stimulation waveforms in response to various inputs received by a user input device 858. The interface control circuitry 854 includes the stimulation control circuitry 320.

[0074] In various embodiments, the external programmer 802 can have operating modes including a composition mode and a real-time programming mode. Under the composition mode (also referred to as a pulse pattern composition mode), the user interface 810 is operative and the programming control circuit 816 is not operative. The programming control circuit 816 does not dynamically update the values ​​of the plurality of stimulation parameters in response to a change in any of the one or more stimulation waveforms. Under the real-time programming mode, both the user interface 810 and the programming control circuit 816 are operative. The programming control circuit 816 dynamically updates the values ​​of the plurality of stimulation parameters in response to a change in any of the one or more stimulation waveform sets and transmits the plurality of stimulation parameters with the updated values ​​to the implantable stimulator 704.

[0075] 9 illustrates an embodiment of a sensor 960 and a therapy device 904 that provides therapy to a patient and controls the delivery of therapy using a sensed therapy control signal. The therapy device 904 can be implemented as a stimulator 104, including but not limited to various embodiments of the stimulator 104 described herein, that delivers neurostimulation energy and controls the delivery of the neurostimulation energy using a therapy control signal sensed using the sensor 960. The therapy control signal can include an input signal for a closed loop system that adjusts the delivery of therapy based on the patient's condition and / or response to the therapy. The sensor 960 can include one or more implantable sensors 962 configured to be implanted in the patient, one or more external sensors 964 configured to be externally attached or otherwise attached to the patient, and / or one or more remote sensors 966 configured to be located remotely from the patient. When the therapy device 904 is configured to be an implantable therapy device, such as the implantable stimulator 704, the implantable sensor(s) 962 can each be configured to be included in the implantable therapy device and / or be a separate implantable device communicatively coupled to the implantable therapy device via a wired or wireless connection. The external sensor(s) 964 and the remote sensor(s) 966 can each be configured to be communicatively coupled to the implantable therapy device via a wireless connection. In one embodiment, the sensor 960 includes only the implantable sensor 962. In other embodiments, the sensor 960 can include any combination of the implantable sensor(s) 962, the external sensor(s) 964, and the remote sensor 966.

[0076] The sensor 960 may include one or more physiological sensors that detect one or more physiological signals from the patient. The one or more physiological signals may include one or more electrophysiological signals, such as one or more neural signals. Examples of such one or more neural signals may include signals indicative of local field potentials (LFPs, oscillatory signals from the brain) and / or evoked compound action potentials (ECAPs). Sensors that detect such neural signals may include electrodes, such as electrodes incorporated on one or more implanted leads (e.g., electrodes 406 on leads 408A and 408B) and / or the implantable medical device (e.g., the IPG 404, including electrodes 426 on the IPG case 422 and / or electrodes 428 in the IPG header 424).

[0077] The sensor 960 may include one or more sensors that sense a physiological condition of the patient. In various embodiments, the physiological condition may be used as an indication of how quickly one or more sensed physiological signals are changing and therefore how frequently these physiological signals should be measured in order to timely adjust the delivery of therapy based on changes in the patient's needs as indicated by the one or more sensed physiological signals. In various embodiments, the physiological condition includes an activity level and the sensor 960 includes one or more activity sensors that sense one or more activity signals indicative of the patient's activity level. The one or more activity sensors may include one or more accelerometers. If the therapy device 904 is configured to be an implantable therapy device, such as an IPG 404, each of the one or more accelerometers may be included in the IPG 404 or incorporated on the implantable lead 408A or 408B.

[0078] The sensor 960 may include one or more sensors that detect one or more environmental signals indicative of the patient's environment, such as temperature, pressure, humidity, altitude, and other signals that may affect a particular physiological function, such as neural activity, of the patient.

[0079] The therapy device 904 can include a therapy output device 912 and a therapy control circuit 914. The therapy output device 912 can provide therapy to the patient. The therapy control circuit 914 can control the delivery of therapy using a therapy control signal sensed using a sensor 960. In various embodiments, the therapy control circuit 914 controls the delivery of therapy by executing a closed loop control algorithm using one or more sensed input parameters derived from the sensed therapy control signal. The sensor 906 includes a sensor that senses a signal used to derive the one or more sensed input parameters.

[0080] The therapy device 904 can be configured to be an implantable medical device, such as an IPG, that provides therapy in the form of electrical stimulation pulses to the patient. In one embodiment, the therapy device 904 is implemented as an implantable stimulator, such as the implantable stimulator 704, that delivers neural stimulation to the patient. The neural stimulation can be delivered, for example, as neural stimulation pulses. The therapy device 912 can be implemented as 212 and the therapy control circuitry 914 can be implemented as the stimulation control circuitry 714. The therapy device 912 uses sensed therapy control signals to provide closed-loop control of the neural stimulation delivery from the stimulation output circuitry to the stimulation control circuitry 714.

[0081] 10 illustrates an embodiment of a system 1070 including a therapy output device 912 and a therapy control circuit 1014. The therapy control circuit 1014 may represent an example of a therapy device 914 and may receive sensed therapy control signals and use the sensed therapy control signals to control the delivery of therapy. In the illustrated embodiment, the therapy control circuit 1014 includes a therapy controller 1072, a therapy parameter adjuster 1074, a physiological condition detector 1076, a measurement system 1078, and an update rate adjuster 1080.

[0082] The therapy controller 1072 can control the delivery of therapy using the therapy parameters. The delivery of therapy can be controlled by executing a closed-loop control algorithm that uses the therapy parameters. The therapy parameter adjuster 1074 can adjust the therapy parameters using one or more sensed input parameters derived from the sensed therapy control signal. In various embodiments, the therapy parameter adjuster 1074 adjusts the therapy parameters using the one or more sensed input parameters at a therapy update rate. The therapy update rate is how often the therapy parameters should be adjusted in response to changes in the one or more sensed input parameters. In other words, the therapy update rate is how often a measurement(s) of one or more sensed input parameters can be used to adjust the stimulation parameters.

[0083] The physiological condition detector 1076 can detect the patient's physiological condition using one or more of the sensed physiological signals of the therapy control signals. Examples of physiological conditions include sleeping, cooking, sitting, exercising, showering, and walking. The patient's physiological condition to be detected can be determined by the need for therapy control and design considerations for detecting and processing the sensed signals. In various embodiments, the physiological condition detector 1076 can detect an activity level using one or more of the sensed activity signals. The activity level is a measure of the patient's physical activity level. In one embodiment, the patient's physiological condition is represented by the activity level alone. In some other embodiments, the patient's physiological condition can be determined by the activity level and one or more sensor signals. The measurement system 1078 can measure one or more of the sensed signals of the therapy control signals at a sensing update rate and generate one or more sensed input parameters based on the measurements. In various embodiments, the measurement system 1078 can be configured to perform various functions necessary to generate one or more sensed input parameters by measuring one or more of the sensed therapy control signals. The sensing update rate is the frequency at which one or more sensed signals are measured to generate one or more sensed input parameters. In various embodiments, the sensing update rate determines when the next measurement should be made and the therapy update rate determines when the next adjustment of the stimulation parameters should be made. The update rate adjuster 1080 can adjust the sensing update rate based on one or more rate adjustment parameters including the sensed physiological condition of the patient. In various embodiments, the update rate adjuster 1080 can adjust the sensing update rate and the therapy update rate based on one or more rate adjustment parameters including the sensed physiological condition. The other one or more rate adjustment parameters can include one or more parameters that quantitatively indicate the energy and / or computational resources available to the system 1070.

[0084] System 1070 can be implemented in a therapy device that includes a stimulator described herein (e.g., stimulator 104, stimulator 204, IPG 404, IPG 504, IPG 604, implantable stimulator 704, therapy device 904, and implantable medical device 1104). When closed-loop control is used in such a therapy device, the present subject matter can prevent the therapy control circuitry from always using sensing and therapy update rates established based on a worst-case scenario that requires frequent updates, thereby extending battery life and / or charging cycles, freeing up computing resources that can be used to improve other functions of the implantable medical device, and / or conserving energy used for computing.

[0085] 11 illustrates an embodiment of an implantable medical device 1104. The implantable medical device 1104 may represent an example of a therapy device 904 and may be configured to be an implantable stimulator, such as the implantable stimulator 704. In the illustrated embodiment, the implantable medical device 1104 includes a therapy output device 912, a sensing circuit 1142, an implant telemetry circuit 1144, an implant memory device 1146, a power source 1148, and a therapy control circuit 1114. The implantable medical device 1104 may be configured to be an implantable stimulator 704 having the therapy output device 912 implemented in the stimulation output circuit 212, the sensing circuit 1142 implemented in the sensing circuit 742, the implant telemetry circuit 1144 implemented in the implant telemetry circuit 744, the implant memory device 1146 implemented in the implant memory device 746, the power source 1148 implemented in the power source 748, and the therapy control circuit 1114 implemented in the stimulation control circuit 714.

[0086] The sensing circuitry 1142 can receive the sensed treatment control signals from a sensor, such as the sensor 960. In various embodiments, the sensing circuitry 1142 can condition one or more of the treatment control signals for measurement, such as by amplification and filtering.

[0087] The implant telemetry circuit 1144 can provide wireless bidirectional communication to the implantable medical device 1104. In various embodiments, the wireless bidirectional communication can be performed using near-field magnetic telemetry and / or far-field electromagnetic telemetry. In one embodiment, Bluetooth or Bluetooth Low Energy (BLE) protocols are used for the wireless bidirectional communication.

[0088] The implant memory 1146 can store information necessary for operation of the implantable medical device 1104 and information acquired by the implantable medical device 1104. The information necessary for operation of the implantable medical device 1104 includes one or more therapy programs, such as one or more neurostimulation programs, and treatment parameters for each of the one or more therapy programs.

[0089] The power source 1148 can include one or more batteries. The amount of energy remaining in the one or more batteries can be indicated by a battery level. The battery level can be measured as a percentage of the energy capacity of the one or more batteries. In various embodiments, the one or more batteries can include rechargeable batteries.

[0090] The therapy control circuitry 1114 may represent an example of a therapy control circuitry 1014 implemented in an implantable medical device. In the illustrated embodiment, the therapy control circuitry 1114 is implemented in a main processor 1182 and a co-processor 1184. The main processor 1182 includes a therapy controller 1072 and a therapy parameter adjuster 1074. The co-processor 1184 includes a physiological condition detector 1076, a measurement system 1078, and an update rate adjuster 1080. In various embodiments, the main processor 1182, in addition to executing a closed-loop control algorithm as described above, may execute one or more additional sensing-based algorithms (e.g., diagnostic algorithms and / or control algorithms for one or more additional therapies) using one or more sensed input parameters. The main processor 1182 may also control wireless communication to and from the implantable medical device 1104 using the implant telemetry circuitry 1144. The main processor 1182 and the co-processor 1184 may include circuits implemented in a single processor or multiple processors. In one embodiment, a microcontroller is configured to be the main processor 1182 and another microcontroller is configured to be the coprocessor 1184. In some embodiments, a microcontroller is configured to be the main processor 1182 and additional microcontrollers are configured to be coprocessors that each perform the functions of the therapy control circuitry 1114.

[0091] The update rate adjuster 1080 can adjust at least the sensing update rate based on one or more rate adjustment parameters according to a relationship relating the sensing update rate to the one or more rate adjustment parameters. In various embodiments, the update rate adjuster 1080 can adjust the sensing update rate and the therapy update rate according to a relationship relating each of the sensing update rate and the therapy update rate to one or more rate adjustment parameters. The one or more rate adjustment parameters can include a detected physiological condition (e.g., activity level) of the patient, a battery status that is a measure of the remaining energy of the power source 1148, a main processor status that is a measure of the computing activity level of the main processor 1182, a coprocessor status that is a measure of the computing activity level of the coprocessor 1184, and / or one or more other parameters indicative of the computing resources and / or energy needs of the implantable medical device 1104. In one embodiment, the sensing update rate is equal to the therapy update rate. In another embodiment, the sensing update rate is higher than the therapy update rate (e.g., to allow multiple measurements of one or more sensed signals to generate one or more sensed input parameters by averaging). In another embodiment, the sensing update rate is lower than the treatment update rate (eg, to allow for immediate treatment changes and scheduled treatment changes at a later time before the next sensing update).

[0092] 12 illustrates an embodiment of one or more physiological condition sensors 1286 and a physiological condition detector 1276 for detecting a physiological condition of a patient. The physiological condition detector 1276 may represent an example of the physiological condition detector 1076, where one or more physiological signals sensed using the physiological condition sensor(s) 1286 may be used to detect a physiological condition of a patient. The physiological condition sensor(s) 1286 may be one or more of the sensors 960. Examples of physiological conditions to be detected by the physiological condition detector 1276 include sleeping, cooking, sitting, exercising, showering, and walking.

[0093] In the illustrated embodiment, the physiological condition sensor(s) include one or more activity sensors 1288 capable of detecting one or more activity signals. The activity sensor(s) 1288 may include one or more accelerometers 1290 each generating an accelerometer signal that is an activity signal. The physiological condition detector 1276 includes an activity level detector 1292 that detects an activity level using the one or more sensed activity signals. The activity level is a measure of the patient's physical activity level. In various embodiments, the activity level may represent the patient's overall physical activity level and may be determined using a single activity signal or a combination of activity signals. In various embodiments, the activity level detector 1292 may generate discrete activity level values ​​each corresponding to a range of the patient's physical activity level. Each discrete value may correspond to a physiological state of the patient (e.g., sleeping, cooking, sitting, exercising, showering, or walking), although it may be necessary to use additional information to verify whether the patient is actually in that physiological state. In various embodiments, the activity level alone (e.g., representative of the patient's overall physical activity level) is sufficient for use as a rate adjustment parameter. The use of additional activity signals may require additional sensor(s) and / or increase the computational activity, and therefore power consumption, of the implantable medical device 1104.

[0094] 13 illustrates an embodiment of an update rate adjuster 1380, which may represent an example of an update rate adjuster 1080. In the illustrated embodiment, the update rate adjuster 1080 includes a lookup table 1394 representing a relationship relating the sensing update rate to one or more rate adjustment parameters, or a relationship relating each of the sensing update rate and the therapy update rate to one or more rate adjustment parameters. The update rate adjuster 1380 may adjust at least the sensing update rate based on the one or more rate adjustment parameters using the lookup table 1394. In various embodiments, the update rate adjuster 1080 may adjust the sensing update rate and the therapy update rate using the lookup table 1394.

[0095] The relationship represented by the lookup table 1394 may be established using results from research and experimentation. In various embodiments, the relationship may be established by balancing treatment and design considerations, such as risk of inappropriate treatment (e.g., excessive or insufficient neurostimulation), battery management considerations regarding the sensing update rate and / or therapy update rate, and available computational resources of the implantable medical device 1104. In various embodiments, the relationship may be empirically tuned by updating the patient lookup table 1394 based on relevant aspects of the performance of the implantable medical device 1104 after implantation in a patient. In various embodiments, the relationship reflects the sensitivity of the sensing update rate and therapy update rate to changes in the detected activity level (e.g., number of discrete values). In various embodiments where the treatment includes delivery of neural stimulation pulses, the sensing update rate and therapy update rate may be determined based on the pulse frequency (e.g., to allow stimulation parameters to be adjusted for each pulse of the neural stimulation pulses).

[0096] 14 illustrates an embodiment of a method 1400 for providing therapy to a patient. Method 1400 can be performed by system 1070 and any therapy device in which system 1070 is implemented, including but not limited to the therapy devices described herein (e.g., stimulator 104, stimulator 204, IPG 404, IPG 504, IPG 604, implantable stimulator 704, therapy device 904, and implantable medical device 1104).

[0097] At 1410, therapy is provided to the patient. In various embodiments, therapy is provided from a therapy output device, such as a stimulation output circuit capable of delivering neurostimulation.

[0098] At 1420, the therapy delivery is controlled using the therapy parameters. In various embodiments, the therapy delivery is controlled using a therapy control circuit, such as a stimulation control circuit that uses the stimulation parameters to control the delivery of the neurostimulation. The stimulation output circuit and the stimulation control circuit can be part of an implantable neurostimulator. The control of the therapy delivery at 1420 can include steps 1421-1426 as shown in FIG.

[0099] At 1421, sensed therapy control signals are received from one or more sensors. The therapy control signals include all sensed signals used to control the delivery of therapy, including input signals to the closed loop control algorithm. In various embodiments, the sensed therapy control signals include one or more electrophysiological signals sensed from the patient. If the therapy includes neurostimulation, the one or more electrophysiological signals may include one or more neural signals indicative of the patient's neural activity that are used to determine and adjust stimulation parameters. At 1422, one or more of the received sensed therapy control signals are measured at a sensing update rate. At 1423, one or more sensed input parameters are generated based on the measurements.

[0100] At 1424, the patient's physiological condition is detected using one or more physiological signals of the received sensed therapy control signals. For example, one or more activity signals, which may be sensed using one or more accelerometers, may be used to detect the patient's activity level as the physiological condition. The activity level is a measure of the patient's physical activity level. In various embodiments, the physiological condition is represented by only the sensed activity level. In various other embodiments, one or more additional rate adjustment parameters are used to determine the patient's physiological condition, such as sleeping, cooking, sitting, exercising, showering, and walking. At 1425, the sensing update rate is adjusted based on one or more rate adjustment parameters including the detected physiological condition. In various embodiments, the sensing update rate is adjusted using only the detected physiological condition. In various other embodiments, the sensing update rate is adjusted using the detected physiological condition and one or more parameters quantitatively indicative of the energy and / or computational resources available in the therapy device. At 1426, the therapy parameters are adjusted using one or more sensed input parameters. In various embodiments, the therapy parameters are adjusted with a therapy update rate that is adjusted based on one or more rate adjustment parameters that also include a detected physiological condition. In one embodiment, the sensing update rate and the therapy update rate are a common rate. In another embodiment, the sensing update rate is different from the therapy update rate. In various embodiments, each of the sensing update rate and the therapy update rate is adjusted according to a relationship that relates each of the sensing update rate and the therapy update rate to one or more rate adjustment parameters. This relationship may be determined based on research and experimentation and stored for use as a look-up table. This relationship (e.g., look-up table) may be empirically adjusted for a patient as part of therapy adjustments that are performed periodically and / or according to the patient's needs.

[0101] FIG. 15 illustrates an example of parameter update rates as a function of rate adjustment parameters for an implantable therapeutic device 1104 configured to be an implantable neurostimulator. In this example, multiple rate adjustment parameters are used to adjust the parameter update rates according to a relationship between each parameter update rate and the rate adjustment parameter. The parameter update rates include a sensing update rate and a therapy update rate. The rate adjustment parameters include a patient's physiological state, a coprocessor state, a battery state, and a main processor state (as described above with respect to the implantable therapeutic device 1104). The illustrated example shows that the sensing update rate and the therapy update rate are increased when the physiological state corresponds to a high activity level, and are decreased when the physiological state corresponds to a low activity level. Because the therapy parameters are adjusted in response to changes in the patient's needs and / or conditions, and such changes occur at a rate corresponding to the patient's physiological condition, using the physiological condition to determine the parameter update rate reduces the use of energy and computational resources by reducing unnecessary parameter updates (which involve little or no change in parameter value). Co-processor state, battery state and main processor state are also used to achieve a performance balance in controlling the delivery of therapy between available energy and computational resources and the speed of adjusting therapy in response to changing patient needs and / or conditions.

[0102] It is to be understood that the above detailed description is intended to be illustrative, and not restrictive. Other embodiments will become apparent to those skilled in the art upon reading and understanding the above description. The scope of the present invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. [Explanation of symbols]

[0103] 912 Therapeutic output device 1014 Treatment control circuit 1070 System 1072 Treatment Controller 1074 Treatment Parameter Adjuster 1076 Physiological Condition Detector 1078 Measuring System 1080 Update Rate Adjuster

Claims

1. 1. A system for providing therapy to a patient, comprising: a treatment output device configured to provide the treatment to the patient; a therapy control circuit configured to receive a sensed therapy control signal and to control delivery of the therapy using the received sensed therapy control signal; The treatment control circuit comprises: a therapy controller configured to control delivery of the therapy using the therapy parameters; a treatment parameter adjuster configured to adjust the treatment parameters using one or more sensed input parameters; a physiological condition detector configured to detect a physiological condition of the patient using one or more of the received sensed treatment control signals; a measurement system configured to measure one or more of the received sensed treatment control signals at a sensing update rate and generate the one or more sensed input parameters based on the measurements; an update rate adjuster configured to adjust the sensing update rate based on one or more rate adjustment parameters including the detected physiological condition; A system comprising:

2. 10. The system of claim 1, comprising an implantable medical device including the therapy output device and the therapy control circuitry.

3. 3. The system of claim 1, wherein the therapy output device includes a stimulation output circuit configured to deliver neurostimulation to the patient, and the therapy control circuit includes a stimulation control circuit configured to receive the sensed therapy control signal and to control the delivery of the neurostimulation using the received sensed therapy control signal.

4. The system of any one of claims 1 to 3, wherein the update rate adjuster is configured to adjust the sensing update rate based on the detected physiological condition and one or more parameters quantitatively indicative of at least one of energy or computational resources available to the therapy control circuitry.

5. The treatment control circuitry includes: a main processor including the therapy controller and the therapy parameter adjuster; a co-processor including the physiological condition detector, the measurement system, and the update rate adjuster; The system of claim 4 , comprising:

6. Further equipped with a power source, The update rate adjuster comprises: the detected physiological condition; and at least one of a battery state, which is a measure of the remaining energy in the power source, a main processor state, which is a measure of the level of computing activity in the main processor, or a coprocessor state, which is a measure of the level of computing activity in the coprocessor; The system of claim 5 , configured to adjust the sensing update rate based on:

7. 7. The system of claim 1, wherein the therapy parameter adjuster is configured to determine the therapy parameter using the one or more sensed input parameters at a therapy update rate, and the update rate adjuster is configured to adjust the sensing update rate and the therapy update rate based on one or more rate adjustment parameters including the detected physiological condition.

8. 8. The system of claim 7, wherein the sensing update rate and the therapy update rate comprise a common rate.

9. The system of claim 7 , wherein the sensing update rate is different from the therapy update rate.

10. 10. The system of claim 1, wherein the physiological condition detector includes an activity level detector configured to detect an activity level as the physiological condition using one or more activity signals of the received sensing treatment control signals, the activity level being a measure of a physical activity level of the patient, and the update rate adjuster is configured to adjust the sensing update rate based on the one or more rate adjustment parameters including the detected activity level.

11. 11. The system of claim 10, further comprising a sensor configured to be communicatively coupled to the therapy control circuitry, the sensor comprising one or more activity sensors configured to detect one or more activity signals.

12. 12. The system of claim 11, wherein the activity level detector is configured to detect the activity level using a single activity signal from the received sensed treatment control signals.

13. The system of claim 11 , wherein the activity level detector is configured to detect the activity level using a plurality of activity signals from the received sensed treatment control signals.

14. The system of any preceding claim, wherein the update rate adjuster is configured to adjust the sensing update rate according to a relationship relating the sensing update rate to the one or more rate adjustment parameters.

15. The system of claim 14 , wherein the update rate adjuster is configured to adjust the sensing update rate using a lookup table representing the relationship.

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