Systems, methods, and apparatuses for mitigating evoked stimulation

Abstract

A system can regulate the delivery of inductive energy based on determined evoked stimulation. For example, processing circuitry can be configured to determine a parameter related to evoked stimulation at one or more leads of an implantable medical device during delivery of inductive energy from an external device to the implantable medical device. The processing circuitry can also regulate the delivery of inductive energy from the external device based on the parameter such that the parameter related to evoked stimulation does not exceed a predetermined threshold.

Description

[0001] This application is a PCT application claiming priority and benefit to U.S. Provisional Patent Application No. 63 / 569,086, filed March 22, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates in general to mitigating induced stimuli during inductive energy transfer. Background Technology

[0003] When wirelessly recharging an implantable medical device, inductive energy is transferred by coupling the primary coil of an external recharger to the secondary coil in the implantable medical device via a recharge signal. In this way, energy can be transferred through the patient's tissue. The implantable medical device can then be recharged as needed to operate for a longer period than a non-rechargeable power source might be. In addition to using inductive coupling to recharge the power source, the implantable medical device can also utilize inductive coupling to communicate with external devices, such as external programmers. Summary of the Invention

[0004] The examples disclosed herein address problems such as these and others by determining parameters associated with evoked stimuli occurring on a medical lead during the delivery of induced energy (e.g., recharge energy and / or induced communication signals), and by adjusting the delivery of induced energy (e.g., recharge signals or communication signals) based on these parameters to mitigate the evoked stimuli. In the examples, heat at the implanted medical device can be used as a proxy to determine the presence of problematic evoked stimuli that should be mitigated by controlling the recharge power. Consideration of heat or other parameters associated with the evoked stimuli can be used in conjunction with temperature considerations to prevent high levels of recharge that may cause discomfort at low temperatures. In another example, the recharge signal can be modified or combined with a separate signal such that evoked stimuli from the modified recharge signal or the separate signal can be measured from the lead by the implanted medical device, wherein the direct measurement of the modified recharge signal or the separate signal is a parameter associated with the evoked stimuli to determine whether the measured evoked stimuli are problematic and whether they should be mitigated by controlling the recharge power. In yet another example, the recharge signal itself can be measured directly from the lead by the implanted medical device as an evoked stimulus, wherein the direct measurement of the recharge signal as an evoked stimulus is a parameter related to the evoked stimulus to determine whether the measured evoked stimulus is problematic and whether it should be mitigated by controlling the recharge power.

[0005] In some examples, one approach includes: determining, by processing circuitry, parameters associated with evoked stimuli at one or more leads of the implantable medical device during the transfer of induced energy from an external device to the implantable medical device; and adjusting, by processing circuitry, the transfer of induced energy from the external device based on the parameters such that the parameters associated with the evoked stimuli do not exceed a predetermined threshold.

[0006] In some examples, a system includes: processing circuitry configured to: determine parameters related to evoked stimuli at one or more leads of the implantable medical device during the transfer of induced energy from an external device to the implantable medical device; and adjust the transfer of induced energy from the external device based on the parameters such that the parameters related to the evoked stimuli do not exceed a predetermined threshold.

[0007] In some examples, a non-transitory computer-readable medium includes instructions that, when executed by processing circuitry, cause the processing circuitry to: determine parameters related to evoked stimuli at one or more leads of the implantable medical device during the transfer of induced energy from an external device to the implantable medical device; and adjust the transfer of induced energy from the external device based on the parameters such that the parameters related to the evoked stimuli do not exceed a predetermined threshold.

[0008] Some examples include systems, apparatus, and / or methods for providing control over the recharging of an implantable medical device. This includes determining parameters related to induced stimuli at one or more leads of the implantable medical device during the transfer of recharging power from the implantable medical device recharger to charge the implantable medical device. This also includes adjusting the recharging power from the implantable medical device recharger such that the parameters do not exceed predetermined threshold values.

[0009] Examples provide systems, apparatus, and methods for medical systems. This includes an implantable medical device and an implantable medical device recharger, the recharger including a recharging unit that outputs recharging power, wherein the implantable medical device is inductively coupled to the recharging unit. The implantable medical device includes a memory and a processor, and the memory stores instructions that, when executed by the processor, cause the implantable medical device to: determine parameters related to induced stimuli at one or more leads of the implantable medical device during power delivery from the recharger to charge the implantable medical device. The recharger includes a second memory and a second processor, and the second memory stores instructions that, when executed by the second processor, cause the recharging unit to: regulate the recharging power from the recharger such that the parameters do not exceed a predetermined threshold.

[0010] The examples provide systems, apparatus, and methods for medical systems. These include implantable medical devices and implantable medical leads. The implantable medical device is coupled to the implantable medical lead and includes transmitting circuitry, memory, and a processor. The memory stores instructions that, when executed by the processor, cause the implantable medical device to: determine parameters related to an evoked stimulus entering the implantable medical lead during the delivery of recharge power to the implantable medical device; and transmit signals representing the parameters related to the evoked stimulus via the transmitting circuitry.

[0011] Examples provide systems, apparatus, and methods for recharging an implantable medical device, the recharger including a memory, a processor, a recharging unit, and receiver circuitry. The memory stores instructions, when executed by the processor, to recharge the implantable medical device to determine parameters related to evoked stimuli in an implantable medical lead of the implantable medical device inductively coupled to the recharging unit during recharging power transfer from the recharging unit to charge the implantable medical device; and to adjust the recharging power from the recharging unit such that the parameters related to the evoked stimuli do not exceed a predetermined threshold.

[0012] Examples provide systems, apparatus, and methods for controlling the recharging of an implantable medical device. This includes determining heat induced in the implantable medical device. This also includes determining the temperature of one or more parts of the implantable medical device. This further includes determining a recharging power based on the heat induced in the implantable medical device. This also includes determining a recharging power based on the temperature of one or more parts of the implantable medical device. This further includes adjusting the recharging power from the implantable medical device recharger according to the lower of a heat-based power and a temperature-based power.

[0013] The various examples described herein relate to systems, methods, and apparatuses for determining the presence of evoked stimuli on a medical lead during inductive energy delivery, such as recharging a medical device, and for modulating recharging to mitigate the evoked stimuli. Some examples may be applicable to other safety and comfort-related considerations beyond evoked stimuli when recharging or otherwise delivering inductive energy to an implantable medical device. Attached Figure Description

[0014] Figure 1 The environment of an example medical system is shown.

[0015] Figure 2 An example of a medical system is shown.

[0016] Figure 3 An example of a logical operation that can be executed by a medical system to recharge an implantable medical device is shown.

[0017] Figure 4An example of a logical operation that can be performed by a medical system to recharge an implantable medical device is shown, taking into account parameters related to the induced stimulus, such as heat, and also the temperature of the implantable medical device.

[0018] Figure 5 Another example of a logical operation that can be performed by a medical system to recharge an implantable medical device is shown, taking into account parameters related to the induced stimulus, such as heat, and also the temperature of the implantable medical device.

[0019] Figure 6 An example of a medical system that modifies the recharge signal is shown.

[0020] Figure 7 An example of a logical operation that can be performed by a medical system to recharge an implantable medical device by modifying a recharge signal is shown.

[0021] Figure 8 Another example of a logical operation that can be performed by a medical system to recharge an implantable medical device by modifying a recharge signal is shown.

[0022] Figure 9 An example of a medical system is shown that modifies the recharge signal by adding a separate signal to the recharge signal.

[0023] Figure 10 An example of a logical operation that can be performed by a medical system that modifies a recharge signal by adding a separate signal to the recharge signal.

[0024] Figure 11 An example of a logical operation that can be performed by a medical system that modifies a recharge signal by skipping pulses in the recharge signal is shown.

[0025] Figure 12 A graph showing the relationship between induced stimulation and time during recharging of an implantable medical device system is presented.

[0026] Figure 13 An example of a logical operation that can be performed by a medical device system that determines recharge power is shown.

[0027] Figure 14 A normalized graph is shown, illustrating the correlation between induced stimulation on the leads of the implantable medical device during recharging and the heat at the implantable medical device.

[0028] Figure 15 An example medical system is shown.

[0029] Figure 16A schematic block diagram of an implantable medical device is shown.

[0030] Figure 17 A sample block diagram of an example external programmer is shown.

[0031] Figure 18 An example technique for modulating inductive energy transfer for communication based on induced stimuli is shown. Detailed Implementation

[0032] Examples provide the determination of parameters related to induced stimuli of medical leads during the delivery of induced energy (e.g., recharge energy or communication signals) and the modulation of the delivery of induced energy (e.g., recharge signals) to mitigate induced stimuli.

[0033] Inductive coupling refers to the process by which a primary coil generates a magnetic field that induces a current in a secondary coil. In an implantable medical device (IMD) system, the IMD may include one coil, and an external device (e.g., a recharger or programmer) may include another coil. Each coil can switch between the primary and secondary coils depending on whether the device is transferring or receiving energy. In some examples, each device may include two coils configured to operate only as either the primary or secondary coil. Inductive coupling can be used to transfer energy, and this energy can be used for a variety of purposes. For example, inductive coupling can be used to transfer induced energy that a receiving device (e.g., the IMD) can use to recharge a battery. In this case, the induced energy may be referred to as recharge energy. In another example, inductive coupling can be used to transfer induced energy for transmitting information (e.g., data) via modulation of the transferred induced energy or other methods. Inductive energy can also be used for other purposes. In any use case, induced energy may have other effects on materials or devices affected by the magnetic field. For example, induced energy can cause stimulation on implanted components such as leads and lead electrodes.

[0034] In the example of recharging energy, the recharging signal can be inductively coupled to medical leads that are physically and electrically coupled to an implanted medical device. This can lead to unexpected or accidental evoked stimuli at the treatment site caused by the leads. These evoked stimuli can adversely affect the patient. For example, evoked stimuli can cause treatment to deviate from the prescribing physician's treatment sequence. In some cases, such as in deep brain stimulation (DBS) therapy, evoked stimuli can cause physiological damage to the patient if they exceed a safe threshold.

[0035] Many factors can influence the amount of evoked stimulation that occurs. For example, during implantation surgery of an implantable medical device, if an extra lead length is available, this extra lead length can be wrapped around the housing of the implantable medical device. Wrapping the lead around the implantable medical device can induce additional evoked stimulation to the recharge signal entering the lead. Similarly, during unipolar stimulation of the recharge signal using the medical lead, when the housing of the implantable medical device is used as a return lead, the evoked stimulation from the recharge signal can be increased. Although recharge energy is generally described herein as an example, inductive energy used for other purposes, such as transferring information (e.g., data) between devices, can also induce stimulation. The techniques described for recharging can also be applied to any other type of inductive energy transfer.

[0036] Typically, the recharge frequency of an implantable medical device is greater than the frequency of the signal measured by the implantable medical device within the patient. In examples, potential recharge frequencies may include approximately 10 kHz, 20 kHz, 30 kHz, 40 kHz, 50 kHz, 60 kHz, 75 kHz, 100 kHz, and 150 kHz, and frequencies in between. Therefore, implantable medical devices typically do not have the frequency range required to directly measure evoked stimuli from recharge signals. In examples, physiological sensing for closed-loop therapy in deep brain stimulation or spinal cord stimulation, or other forms of neuromodulation in low-power implantable medical devices, may be limited to approximately less than 1 kHz, 5 kHz, or 10 kHz.

[0037] An evoked stimulus is an unintentional or incidental stimulation at the treatment or electrode site when induced energy from a recharger is unintentionally or incidentally coupled to a lead / electrode in addition to its primary target, which is the recharge coupling coil associated with the battery in the implant. Such evoked stimuli often occur when the lead is wound around the implant body during implantation or in the case of monopolar stimulation. Patients may expect short recharge times for implantable medical devices due to the discomfort caused by maintaining the recharger on their body. One aspect of this disclosure could be allowing patients to achieve short recharge times for implantable medical devices and configurations susceptible to evoked stimuli. Without directly sensing or otherwise determining an estimate of the evoked stimulus, the medical system may need to be conservative in its estimation or control to mitigate evoked stimuli at the treatment delivery target; therefore, not all patients can be recharged as quickly as possible.

[0038] Figure 1A typical environment for a medical system 100 is illustrated. In this example, the medical system 100 may include an external medical device 110 and an implantable medical system 130 located within a patient's body 120. The implantable medical system 130 may include an implantable medical device 132. The external medical device 110 may include a recharger for recharging the implantable medical device 132. In this example, the external medical device 110 may be an implantable medical device recharger. In some examples, the external medical device 110 is an example external device that can deliver inductive energy for purposes other than recharging the implantable medical device 132. For example, the external medical device 110 may be an external programmer, which is connected via an external programmer as exemplified by... Figure 15 The illustrated inductive coupling transmits information to the implantable medical device 110 (or the charger can also transmit data to the implantable medical device 132 via inductive coupling). In this way, any external device can modulate the transmission of inductive energy to mitigate induced stimuli when the inductive energy is used for one or more different purposes.

[0039] The implantable medical device 132 can determine parameters related to the evoked stimulus based on a recharge signal generated by the external medical device 110. The implantable medical device 132 can provide the external medical device 110 with a measure of the parameter or evoked stimulus. Additionally or alternatively, the implantable medical device 132 can provide the external medical device 110 with a desired recharge power. In addition to the evoked stimulus, the temperature of the implantable medical device 132 and / or the temperature of the patient's body 120 tissues measured or estimated by the implantable medical device 132 can be used to determine the recharge power.

[0040] The external medical device 110 may be placed on the patient's body 120, such as on the chest of the patient's body 120 or at another location near the implantable medical system 130. The external medical device 110 may be placed on the patient's bare skin, on clothing on the patient's body 120, on medical bandages on the patient's body 120, a combination of these, or on any other material between the patient's body 120 and the external medical device 110 that would allow the implantable medical device 132 to be recharged.

[0041] As discussed above, the example implantable medical system 130 includes an implantable medical device 132, which is already implanted in a subcutaneous pouch 140, but other implantation sites may be used according to protocol. The implantable medical system also includes at least one implantable medical lead 134 or a combination of lead and extension, which is routed between the treatment delivery target 142 and the implantable medical device 132. In this example, the implantable medical lead 134 may connect one or more treatment delivery targets to the implantable medical device 132. In another example, the implantable medical system 130 may be a leadless design and may not include the implantable medical lead 134. In this case, less stimulation may be induced due to the lower aperture of the loops in the stimulation circuitry within the implantable medical device 132.

[0042] In this example, the implantable medical device 132 is an implantable neurostimulator (INS) configured for adaptive deep brain stimulation because the implantable medical lead 134 has a distal end 136 and a distal electrode 138 positioned at a target location within the brain for applying stimulation. Other examples of implantable medical devices include, but are not limited to: neurostimulators for spinal cord stimulation, wherein the implantable medical lead 134 is guided to the spinal cord; neurostimulators for peripheral nerve stimulation, wherein the implantable medical lead 134 is guided to the peripheral nerve; neurostimulators for sacral nerve stimulation, wherein the implantable medical lead 134 is guided to the sacral nerve; neurostimulators for cardiac stimulation, wherein the implantable medical lead 134 is guided to cardiac tissue; and neurostimulators for tibial nerve modulation, wherein the implantable medical lead 134 is absent, etc. The implantable medical system 130 can communicate with an external medical device 110 via wired and / or wireless methods.

[0043] Figure 2An example of a medical system 100 is shown. The medical system 100 may include an external medical device 110, an implantable medical device 132, and an implantable medical lead 134, the latter being attachable to a patient's treatment delivery target 142. The external medical device 110 may include a processor 230, a memory 232, and a recharging unit 234. The memory 232 may store instructions executed by the processor 230. The external medical device 110 may include one or more processors 230. The implantable medical device 132 may include a recharging unit 240, a processor 246, and a memory 248. The memory 248 may store instructions executed by the processor 246. The implantable medical device 132 may include one or more processors 246. Any processor described herein may be referred to as or include processing circuitry. In some examples, processing circuitry may be included within the housing of a single device. In some examples, processing circuitry may be collectively referred to as processing circuitry of a plurality of different devices, such that each device in the device includes at least a portion of the processing circuitry. In this way, different aspects of the technology, or even every aspect of the technology, can be distributed across different portions of the processing circuitry (e.g., processor) of each device in different devices. For example, the processing circuitry of an implantable medical device 132 may perform one or more functions of the technology, and the processing circuitry of an external medical device 110 may perform one or more other functions of the technology.

[0044] The implantable medical device 132 may optionally include a temperature sensor 242 and / or sensing circuitry 244. The temperature sensor 242 measures the temperature of the implantable medical device 132 and / or the temperature of the patient's body surrounding the implantable medical device 132, which can be used for temperature-based control of recharging. In one example, the implantable medical device 132 may have one or more temperature sensors 242. In another example, one or more temperature sensors 242 may measure one or more portions of the implantable medical device 132 and / or the patient's tissue surrounding the implantable medical device 132. Additionally or alternatively, temperature control of recharging may be based wholly or partially on temperature sensing occurring via one or more temperature sensors that may be included at an external medical device 110. The sensing circuitry 244 senses one or more signals on the implantable medical lead 134 or stimulation current path. Each processor may take the form of a general-purpose programmable processor, a dedicated processor, hard-wired digital logic, and combinations thereof.

[0045] The recharge unit 234 can generate induced energy (e.g., recharge energy) as recharge power 210 at a given rate. Recharge power 210 can be coupled from an external medical device 110 to an implantable medical device 132 via the recharge unit 240. An unintended consequence of generating recharge power 210 is that a portion of it may couple to the implantable medical lead 134, thereby causing evoked stimulation at the treatment delivery target 142. This evoked stimulation is generally undesirable and, if excessive, can lead to harm to the patient, including damage to the treatment delivery target 142.

[0046] The evoked stimulus can be determined directly by the implantable medical device 132 via sensing on the lead, or by a proxy via determining parameters associated with the evoked stimulus. In one example, heat at the implantable medical device can be used as a parameter associated with the evoked stimulus, making the determination of heat an effective proxy for determining the evoked stimulus. In another example, the recharge power 210 can be modified, wherein the modified recharge power is a parameter associated with the evoked stimulus, making the determination of the modified recharge power on the lead via direct measurement an effective proxy for determining the evoked stimulus at the implantable medical device 132. As used herein, determination typically includes estimation, measurement, calculation, and combinations thereof. The determination may also include empirical and analytical estimations based on the design and / or testing of the medical device system 100. The design and / or testing of the medical system 100 can be used to configure one or more limitations in the medical system 100. In other words, the medical system 100 can empirically determine the evoked stimulus without actually knowing the magnitude of the evoked stimulus level.

[0047] The implantable medical device 132 may provide a feedback signal 220 to the external medical device 110. This feedback signal 220 may include information related to parameters associated with an evoked stimulus due to recharging, such as the amount of power added to the battery during recharging, which directly relates to the heat of the implantable medical device, a direct measurement of the recharging power that has become an evoked stimulus, a direct measurement of the modified recharging signal that has become an evoked stimulus, the result of a transfer function from recharging power to an evoked stimulus, the desired recharging power, and the temperature of the implantable medical device 132. In one example, the feedback signal 220 may be provided during recharging. In another example, the feedback signal 220 may be provided prior to recharging, and the feedback signal may be used to determine the recharging power. Initially, the recharging power may be set to a known safe level while characterizing the evoked stimulus, and this characterized evoked stimulus may be used for subsequent recharging. In one example, the feedback signal 220 is optional, such as when the external medical device 110 may determine parameters related to the evoked stimulus based on the characteristics of the recharging power 210 output by the external medical device 110.

[0048] The measurement of the evoked stimulus (such as the determination of parameters associated with the evoked stimulus) can be used to determine the recharge power to be output. The recharge power can include any characteristics of the recharge signal, such as magnitude, amplitude, phase, frequency, period, frequency range, bandwidth, time-domain response, etc. In this example, the recharge power can be determined such that the evoked stimulus does not exceed a safe threshold. Other factors can be used to determine an appropriate recharge power to mitigate induced current on the leads and / or address any other recharge-related issues. For example, an additional factor is the measured temperature of the implantable medical device 132. The determination of the recharge power can be performed through any combination of the external medical device 110 and the implantable medical device 132. Furthermore, recharge power control can be time-based. For example, the recharge power can be increased during the initial recharge before the temperature of the battery in the implantable medical device 132 increases due to the side effects of recharging the battery. In this example, the patient and / or medical practitioner can set a configurable recharge power lower than the determined recharge power. In this example, the patient can reduce the configurable recharge power when recharging causes discomfort or other negative side effects. Additionally or alternatively, the medical practitioner may specify a configurable recharge power that the recharge power may not exceed or a configurable recharge power that the maximum evoked stimulation may not exceed. The recharge power may also be based on the type of treatment provided, the type of implantable medical device providing the specific type of treatment, and the target location of the implantable medical device (e.g., treatment delivery target 142). In another example, the medical practitioner may determine that treatment delivery during recharge is not necessary and configure the implantable medical system 130 to not deliver stimulation treatment during recharge. For example, during recharge, the implantable medical system 130 may disconnect the stimulation engine that delivers treatment to the treatment delivery target 142 via the implantable medical lead 134. However, due to the need for continuous treatment, treatment may not be able to be stopped in some patients.

[0049] The external medical device 110 may include a first transmitting circuit 236 for communicating with a second receiving circuit 252 of the implantable medical device 132. The implantable medical device 132 may include a second transmitting circuit 250 for communicating with a first receiving circuit 238 of the external medical device 110. Each transmitting and receiving circuit may transmit and receive an evoked stimulus signal representing an evoked stimulus into and from the implantable medical lead 134. Although shown as different components, each transmitting and receiving circuit may be implemented as a transceiver.

[0050] Figure 3An example of logical operation that can be performed by medical system 100 to recharge implantable medical device 132 is shown. This example operation can begin at operation 310 by determining parameters (such as direct measurements of the evoked stimulus itself or its proxy) related to the evoked stimulus from external medical device 110 to implantable medical lead 134. For example, a measurement of heat occurring in implantable medical device 132 can be used as a parameter related to the evoked stimulus at operation 310. In another example, the recharge power 210 can be modified such that parameters related to the evoked stimulus can be measured by implantable medical device 132 based on the modification at operation 310.

[0051] At operation 320, the recharge power is adjustable such that the parameter associated with the evoked stimulus (which serves as a proxy for a direct measurement of the evoked stimulus) does not exceed a predetermined threshold, and this in turn prevents the evoked stimulus from reaching a level higher than desired. The predetermined threshold for the parameter can be based on the maximum power level of the evoked stimulus that the treatment delivery target 142 can safely receive and the correlation between the parameter and the level of the evoked stimulus. In a first example, the predetermined threshold can be a maximum parameter value associated with the maximum power level of the evoked stimulus that the treatment delivery target 142 can safely receive, which is adjusted by a safety margin. In a second example, the patient can reduce the predetermined threshold when the patient experiences discomfort due to the recharge process. In a third example, the predetermined threshold can be based on the type of stimulation therapy and the type of implantable medical device providing that type of stimulation therapy. In this example, deep brain stimulation (DBS) therapy and DBS implantable medical devices may have a lower predetermined threshold than spinal cord stimulation (SCS) therapy and SCS implantable medical devices. In the fourth example, the predetermined threshold can be based on the configuration of the implantable medical lead 134 established in the stimulation circuitry of the implantable medical device. In this example, the monopolar stimulation configuration may have a lower threshold than the bipolar stimulation configuration because monopolar stimulation may be more susceptible to evoked stimuli. In the fifth example, a recharge power can be determined. In the sixth example, when recharging begins, the implantable medical system 130 can switch from monopolar stimulation to bipolar stimulation and return to monopolar stimulation when recharging is complete or when the recharge power falls below a predetermined value. In the seventh example, an external medical device 110 can request a lead configuration (e.g., monopolar or bipolar stimulation) from the implantable medical system 130 and set the threshold based on the lead configuration.

[0052] Figure 4An example of a logical operation that can be performed by medical system 100 to recharge implantable medical device 132 is shown, taking into account parameters related to the evoked stimulus (such as heating of the implantable medical device) and also considering the temperature of the implantable medical device. While recharging can be temperature-controlled in some recharging systems, and while such temperature control can ultimately provide some level of control over the evoked stimulus during recharging, power in such systems typically spikes to high levels when the temperature is still low. Therefore, temperature control does not provide protection against the evoked stimulus during these high-level spikes in recharging power. Taking into account parameters related to the evoked stimulus (such as heating of the implantable medical device) allows medical system 100 to avoid these high-level spikes in recharging power.

[0053] The operation of this example can be initiated at operation 410 by determining the maximum permissible evoked stimulus threshold based on finding the maximum heat from recharging at the implanted medical device, where the heat at the implanted medical device is a parameter related to the evoked stimulus. The maximum permissible evoked stimulus threshold can be based on the results of experimental, published literature, and standard analyses.

[0054] At operation 420, the thermal recharge power can be determined such that the implantable medical device recharger does not generate evoked stimuli exceeding the maximum permissible evoked stimulus threshold. The maximum permissible evoked stimulus threshold can be empirically measured experimentally, and the maximum heat associated with the maximum permissible evoked stimulus can also be empirically measured. Characterization of the implantable medical system 130 and / or external medical device 110 can be used to establish a relationship between heat (e.g., heat from the implantable medical device 132) and evoked stimuli, and this relationship can be used to determine the thermal recharge power. Reference Figure 14 The normalized graph illustrates an example of the correlation between induced stimulation at the lead of an implantable medical device and the heat induced in the device during recharging. The y-axis 1420 represents the induced stimulation, while the x-axis 14120 represents the heat. It can be seen that curve 1430 exhibits a strong correlation between induced current and heat across the entire normalized range.

[0055] In the example, the heat at the implanted medical device can be based on one or more of the heat on the primary side of the recharger, the battery current of the implanted medical device 132, the power entering the primary side of the resonant circuit, and the temperature of the implanted medical device 132. In another example, the implanted heat can be determined as the power entering the resonant circuit (e.g., the recharge coil and tuning capacitor) of the external medical device 110 minus the heat induced in the external medical device 110 minus the power entering the battery of the implanted medical device 132. Specifically, in one example, the implanted heat can be determined using the equation: Q = Ptank - Qprim - Pins_batt (Equation 1) in Q represents the heat generated by the implanted medical device 132. Ptank is the power entering the LC resonant circuit of the external medical device 110. Qprim is the heat generated in the external medical device 110. Pins_batt is the power entering the 132 battery of the implantable medical device.

[0056] At operation 430, the temperature recharge power can be determined such that the implantable medical device does not exceed its maximum temperature. A side effect of recharging the implantable medical device 132 may be the generation of heat. Monitoring the temperature of the implantable medical device 132, and other precautions can be taken to ensure that the implantable medical device 132 is never damaged and / or the patient is never adversely affected by recharging. In this example, the temperature recharge power may be based on an estimate of the temperature of the patient tissue applied to the implantable medical device 132.

[0057] At operation 440, the recharge power can be determined based on thermal recharge power and temperature recharge power. In this example, the minimum of the thermal recharge power and the temperature recharge power can be the recharge power. In this example, the recharge power of the external medical device 110 can be determined such that the implantable medical device 132 is within a safe operating range for both induced stimulation and temperature, and allows the patient to obtain the fastest recharge time within a safe range. In another example, the recharge power can be set to the lower of the thermal recharge power and the temperature recharge power.

[0058] Figure 5Another example of logical operation that can be performed by medical system 100 to recharge implantable medical device 132 using evoked stimulation and implantable medical device temperature is shown. The operation of this example can be initiated by determining power based on temperature control at operation 510 and power based on heat control at operation 520. In operation 510, the power based on temperature control can be the maximum permissible power for temperature control. In operation 520, heat can be used as a parameter associated with the evoked stimulation, and the heat control power can be determined based on the maximum permissible evoked stimulation. In operation 520, the power based on heat control can be the maximum permissible power for heat control. In the example, different treatments may have different configurable heat limits. For example, for SCS, the evoked stimulation may not pose a high safety risk. Operations 510 and 520 can be performed sequentially or in parallel. At operation 530, the recharge power can be set based on power temperature control and power heat control. In the example, the recharge power can be set to the smaller of power temperature control and power heat control. For initial recharge, known safe values ​​for any combination of recharge power, power temperature control, and power thermal control can be selected.

[0059] At operation 540, it can be determined whether recharging should be stopped. Termination criteria can be used to determine whether recharging should be stopped. Termination criteria may include the recharging current dropping below a recharging current threshold, the recharger voltage exceeding a limit, a fault detected, the external medical device 110 exceeding the recharging range of the implantable medical device 132, the patient stopping recharging, and any other conditions that may be used as termination criteria. When it is determined at operation 540 that recharging should be stopped, recharging can be stopped at operation 550.

[0060] When it is determined at operation 540 that recharging should continue, operations 560 and 570 can be performed. At operation 560, the temperature of the implantable medical device 132 can be read, and at operation 570, the load on the recharging unit of the external medical device 110 can be sensed. In the example, heat at the implantable medical device can be measured, for example, via Equation 1, as discussed above. Operations 560 and 570 can be performed sequentially or in parallel. At operation 580, the applied temperature can be estimated. The applied temperature can be measured by one or more temperature sensors in the implantable medical device 132 and / or the external medical device 110. After operation 580, operation 510 can be performed. In operation 590, heat can be estimated. As noted, in one example, heat can be measured via Equation 1. After operation 590, operation 520 can be performed. The order of operations can be rearranged as long as the overall functionality is similar. For example, the determination to stop recharging at operation 540 can occur before the recharging power is set in operation 530.

[0061] Figure 6 An example of a medical system 100 is shown that modifies a recharge signal to allow determination of parameters associated with an evoked stimulus, wherein the measurement result of the modified recharge signal from the lead is a parameter. The medical system 100 may include an external medical device 110, an implantable medical device 132, and an implantable medical lead 134, the implantable medical lead 134 being attachable to a patient's treatment delivery target 142. The external medical device 110 may include a processor 630, a memory 632, and a recharge unit 634. The memory 632 may store instructions executed by the processor 630. The external medical device 110 may include one or more processors 630. The implantable medical device 132 may include a recharge unit 640, a processor 646, and a memory 648. The memory 648 may store instructions executed by the processor 646. The external medical device 110 may include transmitting circuitry 636 and receiving circuitry 638 to communicate signals to the implantable medical device 132 when an evoked stimulus is determined on the lead. Figure 2 As in the example, the transmitting and receiving circuits can be implemented as different components or transceivers.

[0062] The implantable medical device 132 may include one or more processors 646. The implantable medical device 132 may optionally include a temperature sensor 642 and / or sensing circuitry 644. The temperature sensor 642 measures the temperature of the implantable medical device 132 and / or the temperature of the patient's body surrounding the implantable medical device 132. The sensing circuitry 644 senses one or more signals on the implantable medical lead 134. Each processor may be in the form of a general-purpose programmable processor, a dedicated processor, hard-wired digital logic, and combinations thereof. The implantable medical device 110 may include transmitting circuitry 650 and receiving circuitry 652 to communicate signals to an external medical device 110 when determining parameters related to evoked stimuli on the lead. Figure 2 As in the example, the transmitting and receiving circuits can be implemented as different components or transceivers.

[0063] The recharge unit 634 can generate recharge power 610. Recharge power 610 can be coupled from the external medical device 110 to the implantable medical device 132 via the recharge unit 640 and the implantable medical lead 134. Although the implantable medical device 132 can use sensing circuitry 644 to measure signals from the patient's treatment delivery target 142, generally, because the sensing circuitry 644 of the implantable medical device 132 may have a frequency range lower than the recharge signal's frequency range, the implantable medical device 132 may not be able to directly measure the evoked stimulus as a parameter associated with the evoked stimulus. In this example, a signal different from the recharge signal and the resulting evoked stimulus (such as a frequency different from the recharge signal and the resulting evoked stimulus) can be added to the recharge signal, and this different frequency signal can be measured on the implantable medical device 132 by sensing circuitry 644 to determine the parameter associated with the evoked stimulus. Different frequency signals can be selected such that the sensing circuitry 644 of the implantable medical device 132 can measure different frequency signals. Additionally or alternatively, the sensing hardware of the sensing circuit 644 of the implantable medical device 132 may have an increased frequency response, such that the recharge signal frequency, and thus the evoked stimulus itself, can be directly measured as a parameter related to the evoked stimulus. For example, the sensing circuit 644 may be selected to have a frequency range that is twice the recharge frequency. Additionally or alternatively, another sensing circuit may be added to the implantable medical device 132, which includes a high-frequency response, and this other sensing circuit may be used during recharging to sense the recharge signal as a parameter related to the evoked stimulus during recharging.

[0064] Additionally or alternatively, the recharge power 610 may be filtered by the external medical device 110 to incorporate a signal measurable by the implantable medical device 132 as a parameter associated with the evoked stimulus. For example, the external medical device 110 may skip a recharge cycle or individual pulse to induce a frequency component different from the recharge signal frequency into the recharge power 610, which may be higher or lower. This frequency may be a frequency that can be sensed by one or more electrodes on the leads, depending on the system's capabilities. For example, some leads may be designed to sense bioelectrical signals (evoked action potentials, compound muscle potentials, local field potentials) received at certain frequencies. The frequency of the signal transmitted from the external device may be selected, and this frequency may be sensed and detected by the leads in a similar manner. In determining the parameter associated with the evoked stimulus, the sensing circuitry 644 may apply a filter (such as a bandpass filter) to the sensed signal, or may perform digital operations on the sensed signal, such as a fast Fourier transform (FFT) of the time-domain signal.

[0065] The implantable medical device 132 may provide a feedback signal 620 to the external medical device 110. In this example, the feedback signal 620 is optional. The feedback signal 620 may be the same as or similar to the feedback signal 220.

[0066] Figure 7 An example of logical operations that can be performed by medical system 100 to recharge implantable medical device 132 by modifying a recharge signal is shown. The recharge power 610 can be modified by external medical device 110 such that sensing circuitry 644 of implantable medical device 132 can measure the modified recharge signal as a parameter related to the evoked stimulus at operation 710. In this example, sensing circuitry 644 can also measure signals within the patient's body.

[0067] At operation 720, the implantable medical device 132 can measure a recharge signal as a parameter related to an evoked stimulus at the implantable medical lead 134. In this example, the known relationship between different frequency signals and the recharge signal, along with the measured different frequency signals, can be used to determine the parameter related to the evoked stimulus from the recharge signal. At operation 730, the external medical device 110 can adjust the recharge power such that the parameter related to the evoked stimulus does not exceed a predetermined amount.

[0068] Figure 8 Another example of logical operations that can be performed by medical system 100 to recharge implantable medical device 132 by modifying a recharge signal is shown. This example operation can be initiated by determining power based on temperature control at operation 810 and based on parameters related to the evoked stimulus for evoked stimulus control at operation 820. In operation 810, the power based on temperature control may be the maximum permissible power for temperature control. In operation 820, the power based on parameters related to the evoked stimulus for evoked stimulus control may be the maximum permissible power for the evoked stimulus. Operations 810 and 820 may be performed sequentially or in parallel. At operation 830, the recharge power may be set based on power temperature control and evoked stimulus control. In this example, the recharge power may be set to the minimum of power temperature control and evoked stimulus control. For initial recharge, a known safe value for any combination of recharge power, power temperature control, and power evoked stimulus may be selected.

[0069] At operation 840, it can be determined whether recharging should be stopped. Termination criteria can be used to determine whether recharging should be stopped. Termination criteria may include the recharging current dropping below a recharging current threshold, the recharger voltage exceeding a limit, a fault detected, the external medical device 110 exceeding the recharging range of the implantable medical device 132, the patient stopping recharging, and any other conditions that may be used as termination criteria. When it is determined at operation 840 that recharging should be stopped, recharging can be stopped at operation 850.

[0070] Operations 860 and 870 can be performed when it is determined at operation 840 that recharging should continue. The temperature of the implantable medical device 132 can be read at operation 860, and the evoked stimulus signal can be sensed at operation 870. Operations 860 and 870 can be performed sequentially or in parallel. At operation 880, the applied temperature can be estimated. The temperature can be measured by one or more temperature sensors in the implantable medical device 132 and / or the external medical device 110. After operation 880, operation 810 can be performed. In operation 890, the evoked stimulus at the treatment delivery target 142 can be estimated. After operation 890, operation 820 can be performed. In the example, operation 820 can be performed after operation 870, such as when the parameter associated with the evoked stimulus is a directly sensed evoked stimulus. The order of operations can be rearranged as long as the overall functionality is similar. For example, the determination to stop recharging at operation 540 can occur before the recharging power is set in operation 530.

[0071] Figure 9 An example of a medical system 100 is shown that modifies a recharge signal by adding different frequency signals to the recharge signal, such as by superimposing or interleaving different frequency signals relative to the recharge signal. The medical system 100 may include an external medical device 110, an implantable medical device 132, and an implantable medical lead 134, the latter of which may be attached to a patient's treatment delivery target 142. The external medical device 110 may include a recharge driver 930 and a different frequency driver 940. The implantable medical device 132 may include a stimulation engine 950 and sensing circuitry 960. The implantable medical device 132 may optionally include a temperature sensor 980. The temperature sensor 980 may measure the temperature of the implantable medical device 132 and / or the temperature of the patient's body surrounding the implantable medical device 132. As previously discussed, the temperature of the external medical device 110 may be additionally or alternatively considered for temperature control of the recharge signal.

[0072] The recharge power 910 can be coupled from the external medical device 110 to the implantable medical device 132 via the recharge unit 970 and the implantable medical lead 134. When the recharge driver 930 generates a recharge signal to provide recharge power, the different frequency driver 940 can generate a different frequency signal relative to the recharge signal.

[0073] The recharge signal generated by the recharge driver 930 and the different frequency signals generated by the different frequency drivers 940 can be combined to further generate recharge power 910. Although two driver configurations are disclosed, any circuit capable of superimposing, interleaving, or otherwise combining the recharge signal and the different frequency signals can be used.

[0074] The sensing circuit 960 can measure parameters related to evoked stimuli from different frequency signals generated by different frequency drivers 940. The known relationship between the different frequency signals generated by different frequency drivers 940 and the recharge signal generated by the recharge driver 930, together with the measured different frequency signals sensed on the implantable medical lead 134, can be used to determine parameters related to evoked stimuli from the recharge power 910 to the implantable medical lead 134.

[0075] Different frequencies can be selected such that they fall within the frequency range of the sensing circuit 960. In one example, different frequencies can be selected within the range of 100Hz to 1000Hz, thus frequencies below the recharge frequency. In another example, the sensing circuit 960 may be able to sense signals up to 1kHz, or in yet another example, it may be able to sense signals up to 10kHz. Different frequencies can be selected to minimize interference with the stimulation signal generated by the stimulation engine 950. In one example, when selecting the stimulation signal in 100Hz increments, different frequency signals can be selected as non-incremental 100Hz, such as the prime number 701Hz. Different frequencies and stimulation frequencies of the implantable medical device 132 can be selected to reduce aliasing between the different frequencies and the stimulation frequency. Different frequencies can be selected based on the stimulation frequency. For example, when the stimulation frequency is set in the implantable medical device 132, different frequencies can be determined based on the stimulation frequency.

[0076] The implantable medical device 132 may provide a feedback signal 920 to the external medical device 110. In this example, the feedback signal 920 is optional. The feedback signal 920 may be the same as or similar to feedback signal 220 and / or feedback signal 620. Figure 9 The implantable medical device 132 and external device 110 may include those described above. Figure 2 and Figure 6 Similar components include transmitting and receiving circuits for exchanging feedback signals 920.

[0077] Figure 10 An example of logical operation that can be performed by a medical system 100 is shown, which modifies a recharge signal by superimposing different frequency signals onto it. This example operation can be initiated at operation 1010 by an external medical device 110 superimposing, interleaving, or otherwise combining different frequency signals generated by a different frequency driver 940 with a recharge signal generated by a recharge driver 930. At operation 1020, parameters related to the evoked stimulus can be determined based on the different frequency signals sensed by a sensing circuit 960. At operation 1030, the external medical device 110 can adjust the recharge power such that the parameters related to the evoked stimulus do not exceed a predetermined amount.

[0078] Figure 11 An example of logical operation that can be performed by a medical system 100 is shown, which modifies a recharge signal by skipping pulses in the recharge signal. This example operation can be initiated by an external medical device 110 skipping pulses in the recharge signal to generate a different frequency signal at operation 1110. In this example, the recharge signal can be multiplied by a square wave to skip pulses. In another example, a signal can be subtracted from the recharge signal. At operation 1120, parameters related to the evoked stimulus can be determined based on the different frequency signals sensed by the sensing circuit 960. At operation 1130, the external medical device 110 can adjust the recharge power such that the parameters related to the evoked stimulus do not exceed a predetermined amount.

[0079] Figure 12 A graph showing the relationship between evoked stimuli and time during recharging of an implantable medical device is presented. Axis 1210 can be time, axis 1220 can be the magnitude of a parameter associated with the evoked stimuli, and curve 1230 can be a parameter associated with the evoked stimuli over time for recharging the implantable medical system 130. Recharging of the implantable medical system 130 can begin at time 1240. Curve 1230 can begin at a high level of initial charging. A high level of initial charging is permissible because the battery of the implantable medical system 130 may initially have a low temperature before recharging. Line 1250 can be an unsafe threshold for the parameter associated with the evoked stimuli. Specifically, above line 1250 can be an unsafe level for the parameter associated with the evoked stimuli, while below line 1250 can be a safe level for the parameter associated with the evoked stimuli. Line 1250 can be considered a safe or unsafe level of parameter depending on how line 1250 is defined in relation to the level of evoked stimuli. In the examples, any evoking stimulation devices and / or methods described herein can be used to limit the initial evoking stimulus. For example, the devices and / or methods can limit parameters associated with the evoking stimulus to a safe level.

[0080] Figure 13 Another example of logical operations that can be performed by a medical device system for determining recharge power is shown. At step 1310, heat generated in the implantable medical device can be determined. At step 1320, the temperature of one or more parts of the implantable medical device can be determined. At step 1330, a recharge power target based on the heat generated in the implantable medical device can be determined, such as by lookup table or calculation. At step 1340, a recharge power target based on the temperature of one or more parts of the implantable medical device can be determined, such as by lookup table or calculation. At step 1350, the recharge power from the implantable medical device recharger can be adjusted according to the lower of a heat-based target power and a temperature-based target power.

[0081] Figure 15 Example medical system 1500 is shown. Figure 15 As shown, the medical system 1500 includes an IMD 1506, lead extensions 1510, leads 1514A and 1514B (collectively referred to as leads 1514"), and electrodes 1516 and 1518, all of which can be configured for implantation in a patient 1523. Electrodes 1516 and 1518 may be implanted within the brain 1520 of the skull 1522, but the leads and electrodes may be implanted at any location within the patient, such as the spinal cord, pelvic floor, peripheral nerves, tibial nerve, etc. Furthermore, an external programmer 1504 may be an example external device capable of communicating with the IMD 1506 via inductive energy 1520. Inductive energy 1520 may represent inductive energy or a magnetic field that can be generated by the programmer 1504 and / or the IMD 1506 to transmit information between devices.

[0082] Medical system 1500 can be combined with Figure 1 Similar to system 100, medical system 1500 can also be configured to determine parameters associated with evoked stimuli at one or more leads of the leads 1514 of IMD 1506 during the transfer of induced energy 1530 from external programmer 1504 to IMD 1506. For example, IMD 1506 can be similar to IMD 132, and programmer 1504 can have similar capabilities to recharger 110, particularly relative to regulating induced energy transfer based on evoked stimuli. Furthermore, external programmer 1504 and / or IMD 1506 can be configured to regulate the transfer of induced energy from external programmer 1504 based on parameters such that the parameters associated with evoked stimuli do not exceed predetermined thresholds. External programmer 1504 or IMD 1506 can be configured to sense one aspect of the induced energy transfer (such as load on the primary coil, heat, etc.) and estimate evoked stimuli at one or more leads / one or more electrodes. Based on this parameter, the external programmer 1504 or IMD1506 can reduce the power of the sensed energy when communication needs to be maintained, while also mitigating any possible induced stimuli.

[0083] The external programmer 1504 can be a patient programmer or a clinician programmer that can transmit inductive energy 1530 to the IMD 1506. Inductive energy 1530 may include inductive communication that sends operational information to the IMD 1506. Operational information may include one or more parameters that define stimulation therapy, circulation information, recharge instructions, or any other commands regarding the operation of the IMD 1506.

[0084] Figure 16 It shows Figure 15 Example block diagram of IMD 1506. Figure 16The IMD 1506 can be configured to deliver DBS therapy and / or sensing signals from the patient. Figure 16 In the example shown, IMD 1506 includes a processor 1610, a memory 1611, a stimulus generator 1602, a sensing module 1604, a telemetry module 1608, and a power supply 1620. Each of these modules may be or includes circuitry configured to perform functions belonging to each respective module. For example, processor 1610 may include processing circuitry, sensing module 1604 may include sensing circuitry, and telemetry module 1608 may include telemetry circuitry. Switching module 1604 may not be necessary for a configuration with multiple current sources and current sinks. Memory 1611 may include any volatile or non-volatile medium, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), and flash memory. Memory 1611 may store computer-readable instructions that, when executed by processor 1610, cause IMD 1506 to perform various functions. Memory 1611 may be a storage device or other non-transitory medium.

[0085] Under the control of processor 1610, stimulator 1602 generates stimulation signals for delivery to patient 1512 via a combination of selected electrodes 1516 and 1518. Examples of electrical stimulation parameters believed to be effective in managing motor dysfunction in DBS include: 1. Pulse rate, i.e. frequency: between approximately 0.1 Hz and approximately 500 Hz, such as between approximately 0.1 Hz and 10 Hz, between approximately 40 Hz and 185 Hz, or such as approximately 140 Hz.

[0086] 2. In the case of a voltage control system, the voltage amplitude is between approximately 0.1 volts and approximately 50 volts, such as between approximately 2 volts and approximately 3 volts.

[0087] 3. In alternative current control systems, the current amplitude is between approximately 0.2 mA and approximately 100 mA, such as between approximately 1.3 mA and approximately 2.0 mA.

[0088] 4. Pulse width: Between approximately 10 microseconds and approximately 5000 microseconds, such as between approximately 100 microseconds and approximately 1000 microseconds, or between approximately 180 microseconds and approximately 450 microseconds.

[0089] Therefore, in some examples, the stimulator 202 generates an electrical stimulation signal based on electrical stimulation parameters. Other ranges of treatment parameter values ​​may also be useful and may depend on the target stimulation site within the patient 112. Although stimulation pulses are described, the stimulation signal can be of any form, such as a continuous-time signal (e.g., a sine wave). The stimulation signal or other evoked physiological signal configured to induce ECAP may be similar to or different from the parameter value ranges described above.

[0090] Processor 1610 may include fixed-function processing circuitry and / or programmable processing circuitry, and may include one or more of the following: microprocessor, controller, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), discrete logic circuitry, or any other processing circuitry configured to provide functionality attributable to processor 1610, wherein the processor may be embodied herein as firmware, hardware, software, or any combination thereof. Processor 1610 may control stimulation generator 1602 according to a treatment program stored in memory 1611 to apply one or more program-specified values ​​of stimulation parameters, such as voltage or current amplitude, pulse width, or pulse frequency.

[0091] Electrodes 1516, 1518 on the corresponding leads 1514 can be constructed using various different designs. For example, one or two leads 1514 may include two or more electrodes at each longitudinal location along the length of the lead, such as multiple electrodes at different peripheral locations around the periphery of the lead at each of locations A, B, C, and D. In one example, the electrodes may be electrically coupled to a switching module via a corresponding wire that is straightened or coiled within the housing of the lead and extends to a connector at the proximal end of the lead. In another example, each electrode in the leads may be an electrode deposited on a thin film. The thin film may include conductive traces for each electrode that extend along the length of the film to the proximal end connector. The thin film may then be wound (e.g., helically wound) around an internal component to form the lead 1514. These and other configurations can be used to form leads with complex electrode geometries. Sensing circuitry 1644 can sense one or more signals on the implanted medical lead 1514 or a stimulation current pathway. In various examples, the sensing circuit 1644 may be part of or communicate with the sensing module 1604.

[0092] Under the control of processor 1610, telemetry module 1608 supports wireless communication between IMD 1506 and external programmer 1504 or another computing device. As an update to the program, processor 1610 of IMD 1506 can receive values ​​of various stimulation parameters (such as magnitudes and electrode combinations) from programmer 1504 via telemetry module 1608. Updates to the treatment program can be stored in memory 1611. Furthermore, processor 1610 can control telemetry module 1608 to send alarms or other information to programmer 1504, indicating lead movement relative to tissue. Telemetry module 1608 in IMD 1506, as well as telemetry modules in other devices and systems described herein (such as programmer 1504), can communicate via radio frequency (RF) communication technology. Additionally, telemetry module 1608 can communicate with external medical device programmer 1504 via proximal sensing interaction between IMD 1506 and programmer 1504 (e.g., sensing the transfer of energy 1530). Therefore, the telemetry module 1608 can continuously send information to the external programmer 1504 at periodic intervals or upon request from the IMD 1506 or the programmer 1504.

[0093] Telemetry module 1608 can transmit and / or receive information via one or more antennas using different communication modes. For example, telemetry module 1608 can communicate with external programmer 1504 or other external or implanted devices via the transfer of induced energy through one or more antennas. Transmitting circuit 1630 can be configured to transmit information via induced energy transfer, and receiving circuit 1632 can be configured to receive information via induced energy transfer. Transmitting circuit 1630 and receiving circuit 1632 can be respectively connected to… Figure 2 The transmitting circuit 250 and receiving circuit 252 of the IMD 132 are similar.

[0094] Power supply 1620 delivers operating power to the various components of IMD 1506. Power supply 1620 may include a small rechargeable or non-rechargeable battery and power generation circuitry to generate operating power. Recharging is achieved via proximal inductive interaction between an external charger and an inductive charging coil within IMD 1506. In some examples, the power requirement may be small enough to allow IMD 1506 to utilize patient movement and implement kinetic energy harvesting for trickle charging of the rechargeable battery. In other examples, conventional batteries may be used for a limited time.

[0095] Figure 17An example block diagram of an example external programmer 1504 is shown. While the programmer 1504 is generally described as a handheld device, it can be a larger portable device or a more stationary device. In some examples, the programmer 1504 may be referred to as a tablet computing device. Furthermore, in other examples, the programmer 1504 may be included as part of a bedside monitor and an external charging device, or may include the functionality of an external charging device. Figure 17 As illustrated, programmer 1504 may include processor 1710, memory 1711, user interface 1702, telemetry module 1708, and power supply 1720. Memory 1711 may store instructions that, when executed by processor 1710, enable processor 1710 and external programmer 1504 to provide the functionality attributed to external programmer 1704 throughout this disclosure. Each of these components or modules may include circuitry configured to perform some or all of the functionality described herein. For example, processor 1710 may include processing circuitry configured to perform the processes discussed with respect to processor 1710.

[0096] Generally, programmer 1504 includes any suitable hardware arrangement, individually or in combination with software and / or firmware, to perform techniques attributable to programmer 1504 and its processor 1710, user interface 1702, and telemetry module 1708. In various examples, programmer 1504 may include one or more processors, which may include fixed-function processing circuitry and / or programmable processing circuitry, such as those formed by, for example, one or more microprocessors, DSPs, ASICs, FPGAs, or any other equivalent integrated or discrete logic circuitry, and any combination of such components. In various examples, programmer 1504 may also include memory 1711 (such as RAM, ROM, PROM, EPROM, EEPROM, flash memory, hard disk, CD-ROM) containing executable instructions for causing one or more processors to perform actions attributable to them. Furthermore, although processor 1710 and telemetry module 1708 are described as separate modules, in some examples, processor 1710 and telemetry module 1708 may be functionally integrated with each other. In some examples, processor 1710 and telemetry module 1708 correspond to various hardware units, such as ASICs, DSPs, FPGAs, or other hardware units.

[0097] Memory 1711 (e.g., a storage device) may store instructions that, when executed by processor 1710, enable processor 1710 and programmer 1504 to provide the functionality attributed to programmer 1504 throughout this disclosure. For example, memory 1711 may include instructions that enable processor 1710 to retrieve a set of parameters from memory, select a spatial electrode motion mode, provide recommended or otherwise facilitate parameter value selection, receive user input and send corresponding commands to IMD 1506, or perform any other function. Furthermore, memory 1711 may include multiple programs, each including a set of parameters defining a stimulation therapy.

[0098] User interface 1702 may include buttons or a keypad, lights, a speaker for voice commands, and a display (such as a liquid crystal (LCD), a light-emitting diode (LED), or an organic light-emitting diode (OLED)). In some examples, the display may be a touchscreen. User interface 1702 may be configured to display any information related to the delivery of stimulation therapy, represented patient behavior, sensed patient parameter values, patient behavior criteria, or any other such information. User interface 1702 may also receive user input. Input may be, for example, pressing a button on the keypad or selecting an icon from the touchscreen.

[0099] Under the control of processor 1710, telemetry module 1708 can support wireless communication between IMD 1506 and programmer 1504. Telemetry module 1708 can also be configured to communicate with another computing device via wireless communication technology or directly with another computing device via a wired connection. In some examples, telemetry module 1708 provides wireless communication via RF or a proximal sensing medium (e.g., via the transfer of induced energy). In some examples, telemetry module 1708 includes an antenna, which can take various forms, such as an internal antenna or an external antenna. In some examples, IMD 1506 and / or programmer 104 can communicate with a remote server via one or more cloud services to deliver and / or receive information between the clinic and / or programmer.

[0100] Telemetry module 1708 can transmit and / or receive information via one or more antennas using different communication modes. For example, telemetry module 1708 can communicate with IMD 1506 or other implanted or external devices via the transfer of induced energy through one or more antennas. Transmitting circuit 1730 can be configured to transmit information via induced energy transfer, and receiving circuit 1732 can be configured to receive information via induced energy transfer. Transmitting circuit 1730 and receiving circuit 1732 can be respectively connected to… Figure 2 The transmitting circuit 236 and receiving circuit 232 of the recharger 110 are similar.

[0101] Examples of local wireless communication technologies that can be used to facilitate communication between the programmer 1504 and the IMD 1506 include RF communication according to the 802.11 or Bluetooth specification set or other standards or proprietary telemetry protocols. In this way, other external devices can be enabled to communicate with the programmer 1504 without establishing a secure wireless connection. As described herein, the telemetry module 1708 can be configured to send spatial electrode movement patterns or other stimulation parameter values ​​to the IMD 1506 for the delivery of stimulation therapy.

[0102] Figure 18 An example technique for modulating inductive energy transfer for communication based on evoked stimuli is shown. (The term "relative to..." is unclear and likely refers to a technical concept or technique.) Figure 15 External programmers 1506 and IMD 1504 description Figure 18 The same technology can be implemented by other devices and is applicable to other uses of inductive energy transfer.

[0103] like Figure 18 As shown in the example, processing circuitry 1710 can control the transmitting circuitry 1730 of telemetry module 1708 to transmit information to IMD 1506 via inductive coupling (1800). For example, transmitting circuitry 1730 can modulate the current on the primary coil antenna to generate a magnetic field that induces a current in the secondary coil antenna of IMD 1506. During the transmission of induced energy, transmitting circuitry can sense the load from IMD 1506 and determine the load on transmitting circuitry (1802). In some examples, processing circuitry 1710 can determine the load based on the load signal generated by transmitting circuitry 1730.

[0104] Processing circuitry 1710 can then determine parameters (1804) related to the evoked stimulus induced on one or more leads of the leads 1514 of the IMD 1506 based on the load amount. In some examples, the IMD 1506 can transmit a signal indicating the load amount at the secondary coil. In some examples, processing circuitry 1710 can determine the parameters based on a Received Signal Strength Indicator (RSSI) (such as an RSSI value received from the IMD 1506). Programmer 1504 or IMD 1506 can continuously perform sensing of the load or other characteristics related to the evoked stimulus before data transmission and / or during data transmission using inductive coupling.

[0105] Processing circuitry 1710 can then control the power of transmitting circuitry 1730 based on parameters associated with the evoked stimulus to alter the induced energy (1806) used to transmit information to IMD 1506. For example, if a parameter is high (e.g., there is a high load that could induce an evoked stimulus on lead 1514), processing circuitry 1710 can control transmitting circuitry 1730 to reduce the transmission power used for induced energy. Processing circuitry 1710 can compare the determined parameter to a parameter threshold and adjust the induced power in response to a parameter exceeding a threshold indicating an evoked stimulus (or an undesirable stimulus to the patient). In other words, processing circuitry 1710 and / or transmitting circuitry 1730 can iteratively adjust induced energy delivery to provide sufficient energy to transmit data while mitigating any evoked stimulus. In some examples, transmitting circuitry 1730 can gradually and / or iteratively increase the transmission power of induced energy until IMD 1506 confirms receipt of a signal, and then continue transmitting at that level of power to reduce the likelihood of transmitting energy at unnecessarily high levels. Figure 18 The process can continue in the loop during the induction of energy transfer to monitor energy transfer.

[0106] The following embodiments are described in this article.

[0107] Example 1. A method comprising: determining, by processing circuitry, parameters related to induced stimuli at one or more leads of the implantable medical device during the transmission of induced energy from an external device to the implantable medical device; and adjusting, by the processing circuitry, the transmission of the induced energy from the external device based on the parameters, such that the parameters related to the induced stimuli do not exceed a predetermined threshold.

[0108] Example 2. The method according to Example 1, wherein the parameter associated with the evoked stimulus is determined at least in part based on the characterization of the relationship between the sensing energy of the external device and the evoked stimulus to the one or more leads.

[0109] Example 3. The method according to any one of Examples 1 or 2, the method further comprising: generating a low-frequency signal independent of the sensed energy; and wherein determining the parameter associated with the induced stimulus comprises: detecting the low-frequency signal at one or more leads of the implantable medical device.

[0110] Example 4. According to the method of Example 3, wherein the implantable medical device is configured to measure a frequency range including the low-frequency signal.

[0111] Example 5. The method according to any one of Examples 3 or 4, the method further comprising: generating a recharge signal by a first driver; and generating the low-frequency signal by a second driver.

[0112] Example 6. The method according to any one of Examples 3 to 5, wherein the low-frequency signal is selected to reduce aliasing in the stimulation frequency range entering the implantable medical device.

[0113] Example 7. The method according to any one of Examples 3 to 6, wherein: stimulation is provided by the implantable medical device at a stimulation frequency; and a low-frequency signal is selected such that: interference between the stimulation frequency and the additional low-frequency signal is reduced, or the interaction between the low-frequency signal and the physiological response is minimized.

[0114] Example 8. The method according to any one of Examples 3 to 7, the method further comprising: determining a maximum power such that the parameter associated with the evoked stimulus does not exceed the predetermined threshold; and wherein adjusting the transmission of the induced energy comprises: adjusting the induced energy to a level less than the maximum power.

[0115] Example 9. The method according to any one of Examples 1 to 8, the method further comprising: detecting the evoked stimulus by a sensing circuit; and wherein the sensing circuit has a frequency range for measuring the induced energy sensed on the one or more leads.

[0116] Example 10. The method according to any one of Examples 1 to 9, wherein the induced energy includes a skip pulse to generate different frequency components induced on the one or more leads.

[0117] Example 11. The method according to any one of Examples 1 to 10, wherein the predetermined threshold is based at least in part on at least one of the type of the implantable medical device and the patient's treatment delivery target location.

[0118] Example 12. The method according to any one of Examples 1 to 11, wherein the external device includes an implantable medical device recharger, wherein the sensed energy includes recharge power for charging the implantable medical device, and wherein the transmission of the sensed energy includes the recharge power from the implantable medical device recharger.

[0119] Example 13. The method according to Example 12, wherein the parameter determined in relation to the evoked stimulus is at least partially based on heat.

[0120] Example 14. The method according to any one of Examples 12 or 13, wherein the determination of the parameter associated with the induced stimulus is based at least in part on: modifying the recharge signal of the recharge power using a signal different from the recharge signal included in the recharge power, and sensing the signal different from the recharge signal by the implanted medical device at one or more leads.

[0121] Example 15. The method according to any one of Examples 12 to 14, the method further comprising: determining a first maximum recharge power based at least in part on the parameters associated with the evoking stimulus; determining a second maximum recharge power based at least in part on the measured temperature; and wherein adjusting the recharge power comprises: adjusting the recharge power based at least in part on the first maximum recharge power and the second maximum recharge power.

[0122] Example 16. The method according to Example 15, wherein adjusting the recharge power includes: selecting the lower of a first maximum recharge power and a second maximum recharge power.

[0123] Example 17. The method according to any one of Examples 1 to 11, wherein the external device is an external programmer, and wherein the sensing energy includes inductive communication for transmitting operational information from the external device to the implantable medical device.

[0124] Example 18. A system comprising: processing circuitry configured to: determine parameters related to evoked stimuli at one or more leads of the implantable medical device during the transmission of evoked energy from an external device to the implantable medical device; and adjust the transmission of the evoked energy from the external device based on the parameters such that the parameters related to the evoked stimuli do not exceed a predetermined threshold.

[0125] Example 19. The system according to Example 18, wherein the parameters associated with the evoked stimulus are determined at least in part based on the characterization of the relationship between the sensing energy of the external device and the evoked stimulus to the one or more leads.

[0126] Example 20. The system according to any one of Examples 18 or 19, the system further comprising: generating a low-frequency signal independent of the sensed energy; and wherein determining the parameter associated with the induced stimulus comprises: detecting the low-frequency signal at one or more leads of the implantable medical device.

[0127] Example 21. The system according to Example 20, wherein the implantable medical device is configured to measure a frequency range including the low-frequency signal.

[0128] Example 22. The system according to any one of Examples 20 or 21, the system further comprising: generating a recharge signal by a first driver; and generating the low-frequency signal by a second driver.

[0129] Example 23. The system according to any one of Examples 20 to 22, wherein the low-frequency signal is selected to reduce aliasing in the stimulation frequency range entering the implantable medical device.

[0130] Example 24. The system according to any one of Examples 20 to 23, wherein: stimulation is provided by the implantable medical device at a stimulation frequency; and a low-frequency signal is selected such that: interference between the stimulation frequency and the additional low-frequency signal is reduced, or the interaction between the low-frequency signal and the physiological response is minimized.

[0131] Example 25. The system according to any one of Examples 20 to 24, the system further comprising: determining a maximum power such that the parameter associated with the evoked stimulus does not exceed the predetermined threshold; and wherein adjusting the transmission of the sensed energy comprises: adjusting the sensed energy to a level less than the maximum power.

[0132] Example 26. The system according to any one of Examples 18 to 25, the system further comprising: detecting the evoked stimulus by a sensing circuit; and wherein the sensing circuit has a frequency range for measuring the induced energy sensed on the one or more leads.

[0133] Example 27. The system according to any one of Examples 18 to 26, wherein the induced energy includes skip pulses to generate different frequency components induced on the one or more leads.

[0134] Example 28. The system according to any one of Examples 18 to 27, wherein the predetermined threshold is based at least in part on at least one of the type of the implantable medical device and the patient's treatment delivery target location.

[0135] Example 29. The system according to any one of Examples 18 to 28, wherein the external device includes an implantable medical device recharger, wherein the sensed energy includes recharge power for charging the implantable medical device, and wherein the transmission of the sensed energy includes the recharge power from the implantable medical device recharger.

[0136] Example 30. The system according to Example 29, wherein the parameters associated with the evoked stimulus are determined at least in part based on heat.

[0137] Example 31. The system according to any one of Examples 29 or 30, wherein the parameter associated with the induced stimulus is determined at least in part based on: the recharge signal of the recharge power modified by using a signal different from the recharge signal included in the recharge power, and the signal different from the recharge signal sensed by the implantable medical device at one or more leads.

[0138] Example 32. The system according to any one of Examples 29 to 31, the system further comprising: determining a first maximum recharge power based at least in part on the parameters associated with the evoked stimulus; determining a second maximum recharge power based at least in part on the measured temperature; and wherein adjusting the recharge power comprises: adjusting the recharge power based at least in part on the first maximum recharge power and the second maximum recharge power.

[0139] Example 33. The system according to Example 32, wherein adjusting the recharge power includes: selecting the lower of a first maximum recharge power and a second maximum recharge power.

[0140] Example 34. The system according to any one of claims 18 to 33, wherein at least one of the external device or the implantable medical device includes at least a portion of the processing circuitry.

[0141] Example 35. The system according to any one of Examples 18 to 34, wherein the external device is an external programmer, and wherein the sensing energy includes inductive communication for transmitting operational information from the external device to the implantable medical device.

[0142] Example 36. The system according to any one of Examples 18 to 35, the system further comprising the external device.

[0143] Example 37. The system according to any one of Examples 18 to 36, the system further comprising the implantable medical device.

[0144] Example 38. The system according to any one of Examples 18 to 37, wherein the system further includes the one or more leads.

[0145] Example 39. A non-transitory computer-readable medium comprising instructions that, when executed by the processing circuitry, cause the processing circuitry to: determine parameters related to evoked stimuli at one or more leads of the implantable medical device during the transmission of induced energy from an external device to the implantable medical device; and adjust the transmission of the induced energy from the external device based on the parameters such that the parameters related to the evoked stimuli do not exceed a predetermined threshold.

[0146] Example 101. A method for controlling the recharging of an implantable medical device, the method comprising: determining a parameter related to an induced stimulus at one or more leads of the implantable medical device during recharging power being transferred from the implantable medical device recharger to charge the implantable medical device; and adjusting the recharging power from the implantable medical device recharger such that the parameter related to the induced stimulus does not exceed a predetermined threshold.

[0147] Example 102. The method according to Example 101, wherein the parameter associated with the evoked stimulus is determined at least in part based on heat.

[0148] Example 103. The method according to Example 101, wherein the parameter associated with the evoked stimulus is determined at least in part based on a characterization of the relationship between the recharging power of the implantable medical device recharger and the evoked stimulus to the one or more leads.

[0149] Example 104. The method according to Example 101, the method further comprising: generating a low-frequency signal independent of the recharge power; and wherein determining the parameter associated with the induced stimulus comprises: detecting the low-frequency signal at one or more leads of the implantable medical device.

[0150] Example 105. The method according to Example 104, wherein the low-frequency signal is within a frequency range that can be measured by the implantable medical device.

[0151] Example 106. The method according to Example 104, the method further includes: generating a recharge signal by a first driver; and generating the low-frequency signal by a second driver.

[0152] Example 107. The method according to Example 104, wherein the low-frequency signal is selected to reduce aliasing in the stimulation frequency range entering the implantable medical device.

[0153] Example 108. The method according to Example 104, wherein stimulation is provided by the implantable medical device at a stimulation frequency; and wherein a low-frequency signal is selected such that interference between the stimulation frequency and the additional low-frequency signal is reduced or the interaction between the low-frequency signal and the physiological response is minimized.

[0154] Example 109. The method according to Example 104, the method further comprising: determining a maximum power such that the parameter associated with the evoked stimulus does not exceed the predetermined threshold; and wherein adjusting the recharge power comprises: adjusting the recharge power to a level less than the maximum power.

[0155] Example 110. The method according to Example 101, the method further comprising: detecting the evoked stimulus by a sensing circuit; and wherein the sensing circuit has a frequency range for measuring the recharge power sensed on the one or more leads.

[0156] Example 111. The method according to Example 101, wherein the recharge power includes a skip pulse to generate a low-frequency component sensed on one or more leads.

[0157] Example 112. The method according to Example 101, wherein the parameter associated with the induced stimulus is determined at least in part based on: modifying the recharge signal of the recharge power using a signal different from the recharge signal included in the recharge power, and sensing the signal different from the recharge signal by the implantable medical device at one or more leads.

[0158] Example 113. The method according to Example 101, the method further comprising: determining a first maximum recharge power based at least in part on the parameters associated with the evoking stimulus; determining a second maximum recharge power based at least in part on the measured temperature; and wherein adjusting the recharge power comprises: adjusting the recharge power based at least in part on the first maximum recharge power and the second maximum recharge power.

[0159] Example 114. The method according to Example 113, wherein adjusting the recharge power includes: selecting the lower of a first maximum recharge power and a second maximum recharge power.

[0160] Example 115. The method according to Example 101, wherein the predetermined threshold is based at least in part on at least one of the type of the implantable medical device and the patient’s treatment delivery target location.

[0161] Example 116. A medical system comprising: an implantable medical device; an implantable medical device recharger, the implantable medical device recharger including a recharging unit for outputting recharging power; wherein the implantable medical device is inductively coupled to the recharging unit; wherein the implantable medical device includes a memory and a processor, and the memory stores instructions that, when executed by the processor, cause the implantable medical device to: determine parameters related to induced stimuli at one or more leads of the implantable medical device during recharging power being delivered from the implantable medical device recharger to charge the implantable medical device; and wherein the implantable medical device recharger includes a second memory and a second processor, and the second memory stores instructions that, when executed by the second processor, cause the recharging unit to: adjust the recharging power such that the parameters related to the induced stimuli do not exceed a predetermined threshold.

[0162] Example 117. The medical system according to Example 116, wherein the implantable medical device determines the parameters associated with the induced stimulus based at least in part on the heat generated at the implantable medical device.

[0163] Example 118. The medical system according to Example 116, wherein the recharge power includes a signal different from the recharge signal of the recharge power and used to determine the parameter associated with the evoked stimulus.

[0164] Example 119. The medical system according to Example 116, wherein the instructions in the second memory, when executed, also cause the recharge unit to generate a low-frequency signal; and wherein the implantable medical device determines the parameters related to the evoked stimulus by detecting the low-frequency signal at one or more leads of the implantable medical device.

[0165] Example 120. The medical system according to Example 116, the medical system further includes a sensing circuit; wherein the sensing circuit is coupled to the implantable medical device; and wherein the sensing circuit has a frequency range for measuring the recharge power sensed on the one or more leads.

[0166] Example 121. The medical system according to Example 116, wherein the instructions in the second memory, when executed, also cause the recharging unit to output the recharging power by skipping pulses to generate an additional low-frequency component within the recharging power sensed on the one or more leads.

[0167] Example 122. The medical system according to Example 116, wherein the implantable medical device determines the parameters associated with the evoked stimulus by sensing the modified recharge signal at one or more leads, at least in part, based on the modified recharge signal of the recharge power.

[0168] Example 123. A medical system comprising: an implantable medical device; an implantable medical lead; wherein the implantable medical device includes a transmitting circuit; wherein the implantable medical device is coupled to the implantable medical lead; and wherein the implantable medical device includes a memory and a processor, the memory storing instructions that, when executed by the processor, cause the implantable medical device to: determine parameters related to an evoked stimulus entering the implantable medical lead during recharging power delivery from a recharger of the implantable medical device to charge the implantable medical device; and transmit a signal representing the parameters related to the evoked stimulus via the transmitting circuit.

[0169] Example 124. The medical system according to Example 123, wherein the implantable medical device determines the parameters associated with the induced stimulus based at least in part on heat.

[0170] Example 125. The medical system according to Example 123, wherein the implantable medical device determines the parameters associated with the evoked stimulus based at least in part on a recharge power modified using a signal different from the recharge power of the recharge signal.

[0171] Example 126. The medical system according to Example 123, wherein the implantable medical device further includes a sensing circuit, and the parameter associated with the evoked stimulus is determined by measuring the evoked stimulus signal at the implantable medical lead through the sensing circuit.

[0172] Example 127. An implantable medical device recharger, the implantable medical device recharger comprising: a memory; a processor; a recharging unit; a receiver circuit; and wherein the memory stores instructions, which, when executed by the processor, cause the processor to: determine parameters related to an evoked stimulus entering an implantable medical lead of the implantable medical device inductively coupled to the recharging unit during recharging power being delivered from the recharging unit to charge the implantable medical device; and adjust the recharging power from the recharging unit such that the parameters related to the evoked stimulus do not exceed a predetermined threshold.

[0173] Example 128. An implantable medical device recharger according to Example 127, wherein the instructions, when executed, further cause the recharge unit to: generate a low-frequency signal independent of the recharge power; and wherein the processor determines the parameters related to the induced stimulus by detecting the low-frequency signal at the lead of the implantable medical device.

[0174] Example 129. An implantable medical device recharger according to Example 128, wherein the low-frequency signal is selected such that interference between the stimulation frequency of the implantable medical device and the additional low-frequency signal is reduced.

[0175] Example 130. An implantable medical device recharger according to Example 127, wherein the instruction, when executed, also causes the recharge unit to output the recharge power by skipping pulses to generate a low-frequency component within the recharge power sensed on the lead.

[0176] Example 131. An implantable medical device recharger according to Example 127, wherein the instructions, when implemented, cause the parameters associated with the induced stimulus to be determined at least in part based on heat at the implantable medical device.

[0177] Example 132. An implantable medical device recharger according to Example 127, wherein determining the parameter related to the evoked stimulus in the implantable medical lead entering the implantable medical device includes: receiving an evoked stimulus signal from the implantable medical device, wherein the evoked stimulus signal represents the evoked stimulus.

[0178] Example 133. A method for controlling the recharging of an implantable medical device, the method comprising: determining heat induced in the implantable medical device; determining the temperature of one or more portions of the implantable medical device; determining a recharging power target based on the heat induced in the implantable medical device; determining the recharging power target based on the temperature of the one or more portions of the implantable medical device; and adjusting a recharging power from a recharger of the implantable medical device according to the lower of the heat-based recharging power target and the temperature-based recharging power target.

[0179] Example 134. The method according to any one of Examples 101 to 115, the method further comprising: stopping the delivery of stimulation therapy during recharging.

[0180] Example 135. The method according to any one of Examples 101 to 115, wherein adjusting the recharge power further comprises: configuring the implantable medical device for bipolar stimulation during recharge; and configuring the implantable medical device for unipolar stimulation when no longer being recharged.

[0181] The techniques described in this disclosure can be implemented, at least in part, in hardware, software, firmware, or any combination thereof. For example, aspects of the described techniques can be implemented within one or more processors, such as fixed-function processing circuitry and / or programmable processing circuitry, including one or more microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuitry, and any combination of such components. The terms "processor" or "processing circuitry" can generally refer to any of the aforementioned logic circuitry, alone or in combination with other logic circuitry, or any other equivalent circuitry. A control unit, including hardware, can also perform one or more of the techniques disclosed herein.

[0182] Such hardware, software, and firmware may be implemented within the same device or in separate devices to support the various operations and functions described in this disclosure. Furthermore, any of the described units, modules, or components may be implemented together or separately as discrete but interoperable logical devices. Describing different features as modules or units is intended to highlight different functional aspects and does not necessarily imply that such modules or units must be implemented by separate hardware or software components. Rather, the functionality associated with one or more modules or units may be performed by separate hardware or software components or integrated within common or separate hardware or software components.

[0183] The techniques described in this disclosure can also be embedded or encoded in a computer-readable medium (such as a computer-readable storage medium) containing instructions. Instructions embedded or encoded in a computer-readable storage medium can cause a programmable processor or other processor to perform the method, for example, when executing those instructions. Computer-readable storage media may include random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, hard disk, CD-ROM, floppy disk, magnetic tape cassette, magnetic media, optical media, or other computer-readable media.

[0184] Although examples have been specifically shown and described, those skilled in the art will understand that various other changes in form and detail may be made without departing from the spirit and scope of this disclosure.

Claims

1. A system comprising: Processing circuit, the processing circuit being configured to: Determine parameters related to induced stimuli at one or more leads of the implantable medical device during the transfer of induced energy from an external device to the implantable medical device; as well as The transmission of the sensed energy from the external device is adjusted based on the parameters so that the parameters associated with the evoked stimulus do not exceed a predetermined threshold.

2. The system of claim 1, wherein the parameter associated with the evoked stimulus is determined at least in part based on a characterization of the relationship between the sensing energy of the external device and the evoked stimulus to the one or more leads.

3. The system according to any one of claims 1 or 2, further comprising: Generate a low-frequency signal independent of the sensed energy; and The parameters associated with the induced stimulus include detecting the low-frequency signal at one or more leads of the implanted medical device.

4. The system of claim 3, wherein the implantable medical device is configured to measure a frequency range including the low-frequency signal.

5. The system according to any one of claims 3 or 4, further comprising: The recharge signal is generated by the first driver; as well as The low-frequency signal is generated by the second driver.

6. The system according to any one of claims 3 to 5, wherein the low-frequency signal is selected to reduce aliasing in the stimulation frequency range entering the implantable medical device.

7. The system according to any one of claims 3 to 6, wherein: The implantable medical device provides stimulation at a specific frequency; and The low-frequency signal is selected such that: The interference between the stimulation frequency and the additional low-frequency signal is reduced, or The interaction between the low-frequency signal and the physiological response is minimal.

8. The system according to any one of claims 3 to 7, further comprising: Determine the maximum power such that the parameters associated with the evoked stimulus do not exceed the predetermined threshold; and The adjustment of the transmission of the induced energy includes: adjusting the induced energy to a level lower than the maximum power.

9. The system according to any one of claims 1 to 8, further comprising: The evoked stimulus is detected by a sensing circuit; and the sensing circuit has a frequency range for measuring the induced energy sensed on the one or more leads.

10. The system according to any one of claims 1 to 9, wherein the induced energy comprises a skip pulse to generate different frequency components sensed on the one or more leads.

11. The system according to any one of claims 1 to 10, wherein the external device comprises an implantable medical device recharger, wherein the sensed energy comprises a recharge power for charging the implantable medical device, and wherein the transmission of the sensed energy includes the recharge power from the implantable medical device recharger.

12. The system of claim 11, wherein the parameter determined in relation to the evoked stimulus is at least partially based on heat.

13. The system of any one of claims 11 or 12, wherein the determination of the parameter associated with the induced stimulus is based at least in part on: the recharge signal of the recharge power modified by using a signal different from the recharge signal included in the recharge power, and the signal different from the recharge signal sensed by the implantable medical device at one or more leads.

14. The system according to any one of claims 11 to 13, further comprising: The first maximum recharge power is determined at least in part based on the parameters associated with the evoking stimulus; The second maximum recharge power is determined at least in part based on the measured temperature; and The adjustment of the recharge power includes: adjusting the recharge power at least in part based on the first maximum recharge power and the second maximum recharge power.

15. The system according to any one of claims 1 to 14, wherein the external device is an external programmer, and wherein the sensing energy includes inductive communication for transmitting operational information from the external device to the implantable medical device.

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