Methods and systems for electrical stimulation adjustment based on patient-specific factors

Abstract

Methods and systems for adjusting electrical stimulation based on patient-specific factors may include the following instructions or actions: receiving information about at least one of: i) the electrical response of the patient's tissue; ii) the patient's response to stimulation; or iii) the arrangement of implanted leads or electrodes of the implanted leads relative to the patient's anatomy; and calculating electrode weights for each of a plurality of electrodes of the implanted lead based on the received information.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Serial No. 62 / 879,256, filed on July 26, 2019, which is incorporated herein by reference. Technical Field

[0003] The present invention relates to the field of implantable electrical stimulation systems and methods of making and using the same. The present invention also relates to methods and systems for adjusting electrical stimulation based on patient-specific factors. Background Art

[0004] Implantable electrical stimulation systems have been shown to treat a variety of diseases and conditions. For example, spinal cord stimulation systems have been used as a treatment modality for treating chronic pain syndromes. Peripheral nerve stimulation has been used to treat chronic pain syndromes and urinary incontinence, while many other applications are being studied. Functional electrical stimulation systems have been used to restore some function to paralyzed limbs in patients with spinal cord injuries. Stimulation of the brain, such as deep brain stimulation, can be used to treat a variety of diseases or conditions.

[0005] Stimulators have been developed to provide therapy for various treatments. A stimulator may include a control module (with a pulse generator), one or more leads, and an array of stimulator electrodes on each lead. The stimulator electrodes are in contact with or near the nerves, muscles, or other tissues to be stimulated. The pulse generator in the control module generates electrical pulses that are delivered to the body tissue by the electrodes. Summary of the invention

[0006] One aspect is a system for generating stimulation parameters for delivering stimulation through at least one of a plurality of electrodes of an implanted lead. The system includes a memory having instructions stored thereon; and a processor coupled to the memory and configured to execute the instructions, the instructions including receiving information about at least one of: i) an electrical response of patient tissue; ii) a patient response to stimulation; or iii) an arrangement of an implanted lead or an electrode of the implanted lead relative to an anatomical structure of the patient; and calculating an electrode weight for each of the plurality of electrodes of the implanted lead based on the received information.

[0007] On the other hand is a non-transitory computer-readable medium having stored thereon instructions executed by a processor, the instructions comprising receiving patient-specific information regarding at least one of: i) an electrical response of the patient's tissue; ii) the patient's response to stimulation; or iii) an arrangement of an implanted lead or electrodes of the implanted lead relative to the patient's anatomy; and calculating an electrode weight for each of a plurality of electrodes of the implanted lead based on the received information.

[0008] In at least some aspects, the electrical response of the patient tissue includes at least one characteristic of the electrical response to at least one electrical pulse delivered to the patient tissue by at least one of the electrodes of the implanted leads. In at least some aspects, the electrical response of the patient tissue includes an electrogram (ESG) or at least one characteristic of the ESG. In at least some aspects, the electrical response of the patient tissue includes at least one of the following: the area under the curve of the ESG, the range of the amplitude of the curve in a defined time window, the length of the curve of the ESG, the energy content of the ESG, the range of the derivative of the ESG in a predetermined time window, the time delay of a specified signal peak of the ESG, the power of the ESG in a predetermined frequency band, the change in the frequency with the highest energy in the ESG in a predetermined frequency band, the change in coherence in the ESG, the quality factor of the specified signal peak of the ESG in a predetermined time window, or the half-width of the full width for a specific signal peak of the ESG in a predetermined time window.

[0009] In at least some aspects, the patient's response to the stimulation includes at least one of patient feedback, clinician feedback, signals from one or more sensors, or measurements based on signals from one or more sensors.

[0010] In at least some aspects, the placement of the implanted leads or electrodes relative to the patient's anatomy includes the location of the implanted leads or electrodes within the patient's anatomy. In at least some aspects, the location is determined based on imaging of the implanted leads or electrodes within the patient's anatomy.

[0011] In at least some aspects, the placement of the implanted leads or electrodes relative to the patient's anatomy includes the lateral distance of the implanted leads or electrodes from the center of the patient's spinal cord, dorsal columns, or dorsal roots, and the longitudinal position of the implanted leads or electrodes along the patient's spinal cord.

[0012] In at least some aspects, the instructions further include generating simulation parameters using at least one of the electrode weights for use with the implanted lead. In at least some aspects, generating stimulation parameters includes generating adjustments to previous stimulation parameters using at least one of the electrode weights for use with the implanted lead. In at least some aspects, generating adjustments includes generating adjustments in response to the manipulation instructions.

[0013] In at least some aspects, the electrode weights are in the range of 0 to 1. In at least some aspects, receiving the information includes: delivering an electrical pulse using the electrode individually for each of the plurality of electrodes; and receiving an electrical response to the delivery, wherein the information is generated based on the received electrical response. In at least some aspects, the information is patient-specific information. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following drawings.In the drawings, like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0015] For a better understanding of the present invention, reference will be made to the following detailed description which should be read in conjunction with the accompanying drawings, in which:

[0016] Figure 1 is a schematic diagram of one embodiment of an electrical stimulation system;

[0017] FIG. 2A to FIG. 2E are schematic diagrams of different arrangements having one or more leads implanted along the spinal cord;

[0018] Figure 3 Five embodiments of different electrical pulse trains for producing an electrical response are shown;

[0019] Figure 4 is a graph of the electrogram (ESG) amplitude for a set of electrodes;

[0020] Figure 5 is a schematic block diagram of a device having a processor and a memory, and a parameter adjustment engine and a weight determination engine stored in the memory;

[0021] Figure 6 is a flow chart of one embodiment of a method of determining electrode weights and using the electrode weights to determine or adjust stimulation parameters;

[0022] Figure 7 is a flow chart of one embodiment of a method for determining electrode weights; and

[0023] Figure 8 is a schematic diagram of one embodiment of components of a stimulation system including an electronics subassembly disposed within a control module according to the present invention. DETAILED DESCRIPTION

[0024] The present invention relates to the field of implantable electrical stimulation systems and methods of making and using the same. The present invention also relates to methods and systems for adjusting electrical stimulation based on patient-specific factors.

[0025] Suitable implantable electrical stimulation systems include, but are not limited to, at least one lead having one or more electrodes disposed on a distal portion of the lead and one or more terminals disposed on one or more proximal portions of the lead. The lead includes, for example, a percutaneous lead, a paddle lead, a cuff lead, or any other arrangement of electrodes on a lead. Examples of electrical stimulation systems having leads are found, for example, in U.S. Patent Nos. 6,181,969, 6,516,227, 6,609,029, 6,609,032, 6,741,892, 7,244,150, 7,450,997, 7,672,734, 7,761,165, 7,783,359, 7,792,590, 7,8 09,446, 7,949,395, 7,974,706, 8,175,710, 8,224,450, 8,271,094, 8,295,944, 8,364,278, 8,391,985, and 8,688,235; and U.S. Patent Application Publication Nos. 2007 / 0150036, 2009 / 0187222, 2009 / 0 276021, 2010 / 0076535, 2010 / 0268298, 2011 / 0005069, 2011 / 0004267, 2011 / 0078900, 2011 / 0130817, 2011 / 0130818, 2011 / 0238129, 2011 / 0313500, 2012 / 0016378, 2012 / 0046710, 2012 / 0071949, 2012 / 0165911, 2012 / 0197375, 2012 / 0203316, 2012 / 0203320, 2012 / 0203321, 2012 / 0316615, 2013 / 0105071, and 2013 / 0197602, all of which are incorporated herein by reference. In the following discussion, percutaneous leads will be exemplified, but it should be understood that the methods and systems described herein are also applicable to paddle leads and other leads.

[0026] Percutaneous leads for electrical stimulation (e.g., deep brain, spinal cord, or peripheral nerve stimulation) include stimulating electrodes, which may be ring electrodes, segmented electrodes that extend only partially around the circumference of the lead, or any other type of electrode, or any combination thereof. The segmented electrodes may be arranged into groups of electrodes, each group having electrodes distributed around the circumference of the lead at a particular longitudinal position. A group of segmented electrodes may include any suitable number of electrodes, including, for example, two, three, four or more electrodes. For purposes of illustration, the leads are described herein with respect to use for spinal cord stimulation, but it should be understood that any of the leads may be used for applications other than spinal cord stimulation, including deep brain stimulation, peripheral nerve stimulation, dorsal root ganglion stimulation, sacral nerve stimulation, or stimulation of other nerves, muscles, and tissues.

[0027] Steering Figure 1 , one embodiment of an electrical stimulation system 10 includes one or more stimulation leads 12 and an implantable pulse generator (IPG) 14. The system 10 may also include one or more of an external remote control (RC) 16, a clinician's programmer (CP) 18, an external trial stimulator (ETS) 20, or an external charger 22. The IPG and ETS are examples of control modules for an electrical stimulation system.

[0028] The IPG 14 is optionally physically connected to the stimulation lead(s) 12 via one or more lead extensions 24. Each lead carries a plurality of electrodes 26 arranged in an array. The IPG 14 includes a pulse generating circuit system that delivers electrical stimulation energy to the electrode array 26 in the form of, for example, a pulsed electrical waveform (i.e., a time series of electrical pulses) according to a set of stimulation parameters. The implantable pulse generator can be implanted in the patient's body, for example, below the patient's clavicle region or within the patient's buttocks or abdominal cavity or any other suitable location. The implantable pulse generator can have multiple stimulation channels that can be independently programmed to control the amplitude of the current stimulation from each channel. In some embodiments, the implantable pulse generator can have any suitable number of stimulation channels, including but not limited to 4, 6, 8, 12, 16, 32 or more stimulation channels. The implantable pulse generator can have one, two, three, four or more connector ports for receiving terminals of a lead or lead extension.

[0029] The ETS 20 may also be physically connected to the stimulation lead 12, optionally via a percutaneous lead extension 28 and an external cable 30. The ETS 20 (which may have a pulse generation circuit system similar to the IPG 14) also delivers electrical stimulation energy to the electrode array 26 in the form of, for example, a pulsed electrical waveform according to a set of stimulation parameters. One difference between the ETS 20 and the IPG 14 is that the ETS 20 is typically a non-implantable device that is used on a trial basis after implantation of the neural stimulation lead 12 and before implantation of the IPG 14 to test the responsiveness of the stimulation to be provided. Any functions described herein with respect to the IPG 14 may likewise be performed with respect to the ETS 20.

[0030] The RC 16 can be used to telemetrically communicate with or control the IPG 14 or ETS 20 via a unidirectional or bidirectional wireless communication link 32. Once the IPG 14 and the neurostimulation lead 12 are implanted, the RC 16 can be used to telemetrically communicate with or control the IPG 14 via a unidirectional or bidirectional communication link 34. Such communication or control allows the IPG 14 to be turned on or off and programmed with different sets of stimulation parameters. The IPG 14 can also be operated to modify the programmed stimulation parameters to actively control the characteristics of the electrical stimulation energy output by the IPG 14. The CP 18 gives a user, such as a clinician, the ability to program stimulation parameters for the IPG 14 and ETS 20 in the operating room and in subsequent sessions. Alternatively or additionally, the stimulation parameters can be programmed via wireless communication (e.g., Bluetooth) between the RC 16 (or an external device such as a handheld electronic device) and the IPG 14.

[0031] The CP 18 may perform this function by communicating indirectly with the IPG 14 or ETS 20 via the wireless communication link 36, via the RC 16. Alternatively, the CP 18 may communicate directly with the IPG 14 or ETS 20 via a wireless communication link (not shown). The stimulation parameters provided by the CP 18 are also used to program the RC 16, so that the stimulation parameters may be subsequently modified by operation of the RC 16 in a standalone mode (i.e., without the assistance of the CP 18).

[0032] For the sake of brevity, the details of the RC 16, CP 18, ETS 20, and external charger 22 are not further described herein. Details of exemplary embodiments of these devices are disclosed in U.S. Patent No. 6,895,280, which is expressly incorporated herein by reference. Other examples of electrical stimulation systems can be found in U.S. Patent Nos. 6,181,969, 6,516,227, 6,609,029, 6,609,032, 6,741,892, 7,949,395, 7,244,150, 7,672,734, and 7,761,165, 7,974,706, 8,175,710, 8,224,450, and 8,364,278; and U.S. Patent Application Publication No. 2007 / 0150036, as well as other references cited above, all of which are incorporated herein by reference.

[0033] Figure 2A One embodiment of a spinal cord stimulation (SCS) system 100 is shown implanted in a patient 40. The SCS system 100 includes an IPG 14 that generates electrical stimulation pulses for stimulation. An electrode array 26 at or near the distal end of an implanted stimulation lead 12 is inserted into the epidural space next to the spinal cord 42. Optionally, a lead extension 24 can be used to connect the lead 12 to the IPG 14.

[0034] like Figure 2A As shown, the spacing of the vertebrae along the spinal cord 42 varies from the cervical region (C1 to C8) to the thoracic region (T1 to T12) to the lumbar region (L1 to L5). In particular, the lower thoracic region and the lumbar region have large differences in spacing. Moreover, due to anatomical differences and the development and degeneration of the spinal cord, the spacing between adjacent vertebrae will vary from patient to patient. Especially at these levels, the position of the electrodes on the implanted leads may vary from patient to patient, even where the leads are implanted at the same spinal cord level. Depending on the relative position of the electrodes relative to the nerve fibers or other neural elements to be stimulated, the activation of nerve fibers through electrical stimulation using the electrodes of the leads can vary significantly.

[0035] FIG. 2B to FIG. 2E The placement of the lead 12 relative to the dorsal roots 290a, 290b is shown, and it is shown that the electrodes of the lead can be positioned at different distances from the dorsal roots, with some electrodes overlapping or near the dorsal roots and other electrodes being farther away from the dorsal roots. Figure 2B and Figure 2C Percutaneous leads are shown, and Figure 2D and Figure 2E A paddle lead is shown. The methods, systems, and arrangements described below can be used with leads placed in the midline, lateral to the midline, near the dorsal column, or near the dorsal root, or any other suitable placement site.

[0036] In at least some electrical stimulation systems, electrode selection, electrode fractionalization (i.e., the fraction of the total current or voltage applied to each of the selected electrodes), total amplitude, or other parameters, or any combination thereof, may be varied or adjusted to manipulate stimulation above or below the lead (or when segmented electrodes are used around the circumference of the lead). When manipulating stimulation, current systems utilize a combination of one or more of the electrode spacing, the spinal cord level(s) at which the lead is implanted, and the average cerebrospinal fluid thickness at the level of the SCS spinal cord to determine adjustments in amplitude to manipulate or reliably increase or decrease stimulation. However, as described above, at the level of the lumbar roots (and possibly other portions of the spinal cord), neural activation can vary dramatically depending on the relative position of the electrodes relative to the neurons to be stimulated. This is also the case when the leads are positioned lateral to the center of the spinal cord, particularly as the lateral distance from the spinal cord increases and the dorsal roots, rather than the dorsal columns, become the primary target of stimulation.

[0037] In order to better manage the determination or adjustment of the amplitude or other stimulation parameters used to manipulate stimulation or to determine effective parameters, information can be obtained from one or more of a variety of sources to generate electrode weights that can be used to modify the determination or adjustment of the amplitude or other stimulation parameters. In at least some embodiments, this information is patient-specific so that the determination or adjustment is tailored to the patient. Examples of such information include, but are not limited to, electrograms or other electrical response measurements or features of such response measurements, anatomical information (which may include patient-specific imaging or information), patient-perceived feedback or discomfort during stimulation, clinician feedback, sensor measurements, the like, or any combination thereof.

[0038] In at least some embodiments, the electrode weights can reflect the efficacy of a single electrode in stimulating patient tissue. (The electrode weights do not represent the subdivision of the stimulation signal between the electrodes, such as the distribution, but represent the effectiveness of the electrodes in stimulating the target tissue). The efficacy can vary significantly with, for example, the position of the electrode relative to the tissue to be stimulated (e.g., the dorsal root of the spinal cord). As an example, due to the position of the lead and the spacing of the electrodes along the lead, when implanted, some electrodes may be positioned closer to the tissue to be stimulated (e.g., the dorsal root) than other electrodes, and therefore, generally have a higher efficacy in producing stimulation. This may be obvious, for example, when the spacing between the electrodes and the spacing between the dorsal roots at different levels of the spinal cord are significantly different, so that when implanted, some electrodes will be positioned near the dorsal root, while some electrodes are positioned farther. These latter electrodes may need to apply a higher amplitude of stimulation to produce an effect similar to that of the electrode closer to the dorsal root. Although the dorsal root is used as an example, it should be understood that this applies to other physiological elements and arrangements of the spinal cord or other anatomical features and elements.

[0039] A variety of different types of information can be used to determine electrode weights. For example, images of implanted leads and surrounding anatomical structures can be used to identify the location of electrodes and leads, such as the lateral distance of the lead relative to the center of the spinal cord, dorsal column, dorsal root, cauda equina, or neuron to be stimulated; alignment of the lead or electrode with the pedicle or other portion of the vertebra; alignment of the lead or electrode with the dorsal root, etc. or any combination thereof. Such information can be obtained using fluoroscopes or any other suitable imaging technology, or can be based on the clinician's knowledge or estimate of where the lead or electrode is implanted.

[0040] Another source of information is the patient's response to stimulation. In at least some embodiments, when stimulated, the patient can provide feedback about the efficacy (e.g., pain relief or paresthesia) or discomfort caused by stimulation. Patient feedback can be verbally performed to the clinician or other individuals who record feedback, or can be input into RC, CP or other devices by the patient, clinician or other individuals. In at least some embodiments, clinicians or individuals other than the patient can observe the patient's response, and feedback is provided to RC, CP or other devices. In at least some embodiments, one or more sensors can be used to measure or monitor patient response. The example of a suitable sensor includes an external sensor arranged on or near the patient's body, or an internal sensor or any combination of an IPG or lead or separated therefrom, or an internal or external sensor. The sensor can transmit the analysis / feature of the measurement result or sensor measurement result to CP, RC, IPG or other devices, or the measurement result, analysis or feature can be received and input by the patient, clinician or other individuals. In other embodiments, any combination of patient feedback, clinician feedback or sensor measurement result / analysis / feature can be used to generate information about the patient's response to stimulation.

[0041] Another source of information is a measurement of an electrical response to an electrical signal, which can be delivered using, for example, one or more of the electrodes of the lead. In addition, the electrical response can be received by one or more of the electrodes of the lead or other electrodes (such as recording electrodes on or near the lead), and the IPG, CP, RC or another device can analyze the received electrical response. The electrical response can be, for example, an evoked response or an evoked composite action potential (ECAP), or can even be a spontaneous response (i.e., a response that is not necessarily generated by an electrical signal from a lead electrode) or any other suitable electrical response.

[0042] An example of an electrical response is an electrogram (ESG), which can be obtained by applying electrical pulses to neural tissue using one or more of the electrodes of the lead. In at least some embodiments, each electrode (or a subset of electrodes) can deliver an electrical pulse individually, and an ESG corresponding to that electrode can be obtained.

[0043] The shape of the electrical pulses and their amplitude, frequency, pulse width, etc. can be selected to enhance the sensing of ESG and may not necessarily be the same as the pulse shape used for therapeutic stimulation. Moreover, the pulse shape can be symmetrical or asymmetrical and can be monophasic, biphasic or polyphasic. Figure 3 Examples of different electrical pulses that can be used are shown. Pulse train 350 is an example of an asymmetric, actively recharging biphasic pulse in which anode sub-pulses 350a are delivered first, followed by cathode sub-pulses 350b. Pulse train 352 is another example of an asymmetric, actively recharging biphasic pulse in which cathode sub-pulses 352a are delivered first, followed by anode sub-pulses 350b. Pulse train 354 is a third example of an asymmetric, actively recharging biphasic pulse in which first sub-pulses 354a alternate between anode sub-pulses and cathode sub-pulses, and second sub-pulses 354b alternate between cathode sub-pulses and anode sub-pulses. Pulse train 356 is a fourth example of an asymmetric, actively recharging biphasic pulse in which anode sub-pulses 356a are delivered first, and there is a relatively long gap between the first sub-pulses 356a and the second sub-pulses 356b. Pulse train 358 is a fifth example of an asymmetric, active recharging biphasic pulse that includes a relatively long gap between first sub-pulses 358a and second sub-pulses 358b, and first sub-pulses 358a alternate between anode sub-pulses and cathode sub-pulses. These are examples, and it should be understood that many other pulse trains may be used.

[0044] Electrodes on the leads or other sensors / electrodes on or near the leads can be used to receive (e.g., sense) the ESG. The ESG can be analyzed using an IPG, CP, RC, or another device to identify and measure one or more features of the ESG. Features can be evaluated in the frequency domain or the time domain. Examples of features of the ESG that can be used to generate electrode weights include, but are not limited to, one or more of the following: the area under the ESG curve, the range of the curve (e.g., the range between the local maximum and the local minimum in a defined time window), the ESG curve length, the ESG energy content, the range of the derivative of the ESG signal in the time window, the time delay of a specified ESG signal peak, the ESG power in a defined frequency band, the change in the ESG centroid frequency (i.e., the frequency with the highest energy) in a defined frequency band, mutual information, entropy, the standard deviation of any of the previous metrics, a change in coherence in the ESG, or a quality factor or FWHM (full width at half maximum) of a specified ESG peak in a predetermined time window.

[0045] As an example of an ESG feature that may be used to determine electrode weights, Figure 4 is a graph of ESG amplitude as a function of the electrodes that deliver the electrical pulses to initiate the ESG. Figure 4 In the example shown in , electrodes 2 and 7 appear to induce higher ESG amplitudes than the other electrodes.

[0046] The methods described herein may be implemented in hardware or software or a combination thereof. As an example, Figure 5 One embodiment of a device 570 is shown that includes a processor 572 and a memory 574. The device 570 may be, for example, Figure 1 14, RC 16, CP 18, or ETS 20, or any other suitable device. It will be appreciated that device 570, processor 572, and memory 574 may be replaced by a plurality of devices, processors, or memories, respectively, and that one or more of the processors and one or more of the memories may be local or non-local.

[0047] In at least some embodiments, the memory 574 includes instructions for a parameter determination engine 576 (or a parameter determination module or a parameter determination algorithm) and a weight determination engine 578 (or a weight determination module or a weight determination algorithm). These engines 576, 578 are stored in the memory and operated in the processor 572 of the device 570. (In some embodiments, the engines 576, 578 can be combined into a single engine).

[0048] Figure 6A method of determining electrode weights and using the electrode weights to determine or adjust stimulation parameters is shown. The method can be implemented in the parameter determination engine 576 (e.g., steps 606 and 608) and the weight determination engine 578 (e.g., steps 602 and 604).

[0049] In step 602, information is obtained for determining the weight of one or more of the electrodes of the lead. The information can be any of the information described above, including but not limited to the electrical response of the patient's tissue (such as ESG, ECAP, evoked response, etc.) or characteristics of the electrical response; the patient's response to stimulation (e.g., patient feedback, clinician feedback, or sensor measurement results / analysis, etc.); or the arrangement of the implanted lead or electrodes on the lead relative to the patient's anatomy, such as the position of the lead or electrode in the patient's tissue (e.g., from imaging or from the clinician's position of the implanted lead). In at least some embodiments, some or all of the information obtained in step 602 is patient-specific. This may result in patient-specific electrode weights.

[0050] In step 604, electrode weights for two or more of the electrodes are determined or calculated using this information. For example, the information provided in step 602 can be used to generate a calibration using any suitable calibration method that determines the relative proportions of the electrodes, which are then used to generate the electrode weights. Figure 7 Examples of methods of determining electrode weights are presented. In at least some embodiments, electrode weights may range from 0 to 1; however, other ranges of electrode weights may also be used.

[0051] In optional step 606, one or more stimulation parameters or instructions for manipulating the stimulation are received. As an example, the stimulation parameter may be stimulation amplitude, selection of one or more electrodes for providing stimulation, selection of electrode subdivisions, etc., or any combination thereof. With respect to instructions for manipulating, such instructions may include moving the stimulation on or under the lead (or around the lead in the case of a segmented electrode) by changing the selection or subdivision of the electrode(s) for providing stimulation or increasing or decreasing the stimulation amplitude, etc., or any combination thereof.

[0052] In step 608, stimulation parameters, or adjustments to current stimulation parameters, are generated using the electrode weights. The generation of stimulation parameters may be based on default settings or based on the stimulation parameters received in step 606 to provide a direction for a set of stimulation parameters. The adjustment to the current stimulation parameters may be based on one or more stimulation parameters or manipulation instructions received in step 606. As an example, the electrode weights may be used to generate or adjust stimulation amplitudes for each of one or more electrodes in the stimulation parameter set.

[0053] In at least some embodiments, the method can include adjusting the selection of electrodes for producing a set of electrodes and corresponding amplitudes that can produce the same (or within a threshold of, for example, 1, 2, 5, or 10%) stimulation output. For example, stimulation can be produced from electrodes that produce a smaller effect without a larger amplitude (e.g., Figure 4 4 to 6 or 9 to 11 in FIG. 10A ) to a nearby electrode (e.g., electrode 7) that can produce a greater effect at a lower amplitude. In at least some embodiments, the system can automatically make this replacement. In other embodiments, the system can present the alternative to the user for approval or confirmation.

[0054] Figure 7 An embodiment of a method for obtaining information and using the information to determine electrode weights is shown. In step 702, an electrical pulse (or multiple pulses) is delivered using one of the electrodes of the lead. Examples of such pulses and the delivery of such pulses are described above. In step 704, an electrical response is received or sensed at another electrode (or even the same electrode). For example, when testing each of the electrodes, a specific one or more (e.g., the most distal or most proximal electrode) of the electrodes of the lead can be selected to receive or sense a response. In some other embodiments, when testing each of the electrodes, two or more of the electrodes can be selected to receive or sense a response.

[0055] In step 706, it is determined whether a threshold has been reached in the received or sensed response. For example, the threshold may be a magnitude threshold of the received or sensed response. As another example, the threshold may be a requirement that a desired characteristic of the response is established or reliably measurable.

[0056] If the threshold is not reached, the stimulation amplitude (or pulse width, etc.) is increased in step 708 and steps 702 to 706 are repeated until the threshold is reached or until a limit on stimulation amplitude or other parameter is reached.

[0057] If the threshold is reached at step 706, then a determination is made as to whether there is another electrode to test at step 710. If so, steps 702 to 710 are repeated for each additional electrode.

[0058] If not (i.e., all electrodes have been tested), then in step 714, electrode weights are generated based on the received or sensed responses. As an example, if the sensed feature is the amplitude of the established feature or the amplitude of the sensed feature, the highest amplitude can be normalized and then weighted based on the highest amplitude - for example, the amplitude of each electrode is divided by the highest amplitude to give an electrode weight in the range of 0 to 1.

[0059] It should be understood that each block of the flowchart diagram and the combination of the blocks in the flowchart diagram and the method disclosed herein can be implemented by computer program instructions. These program instructions can be provided to a processor to generate a machine or engine so that the instructions executed on the processor create a device for implementing the action specified in one or more flowchart blocks disclosed herein. The computer program instructions can be executed by a processor so that the processor performs a series of operating steps to produce a computer-implemented process. The computer program instructions can also enable at least some of the operating steps to be performed in parallel. Moreover, some of the steps can also be performed on more than one processor, such as may occur in a multi-processor computing device. In addition, without departing from the scope or spirit of the present invention, one or more processes can also be performed simultaneously with other processes, or even in a different order than shown.

[0060] The computer program instructions may be stored on any suitable computer-readable medium, including but not limited to RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical storage devices, magnetic cassettes, magnetic tape, magnetic disk storage devices or other magnetic storage devices, or any other medium that can be used to store the desired information and which can be accessed by a computing device.

[0061] Figure 8 8 is a schematic diagram of one embodiment of components of an electrical stimulation system 800 including an electronic subassembly 810 disposed within a control module. It should be understood that the electrical stimulation system may include more, fewer, or different components and may have a variety of different configurations, including those disclosed in the stimulator references cited herein.

[0062] Some of the components of the electrical stimulation system (e.g., power source 812, antenna 818, receiver 802, and processor 804) can be positioned on one or more circuit boards or similar carriers within the sealed housing of the implantable pulse generator, if desired. Any power source 812 can be used, including, for example, a battery such as a primary battery or a rechargeable battery. Examples of other power sources include supercapacitors, nuclear or atomic batteries, mechanical resonators, infrared collectors, thermodynamic energy sources, flexodynamic energy sources, bioenergy sources, fuel cells, bioelectric cells, osmotic pumps, etc., including the power sources described in U.S. Patent No. 7,437,193 (which is incorporated herein by reference).

[0063] As another alternative, power may be supplied by an external power source by inductive coupling via the optional antenna 818 or an auxiliary antenna. The external power source may be in a device mounted on the user's skin, or in a unit that is permanently or periodically provided near the user.

[0064] If the power source 812 is a rechargeable battery, an optional antenna 818 can be used to charge the battery if necessary. Power can be provided to the battery for recharging by inductively coupling the battery to a recharging unit 816 external to the user via the antenna. Examples of such arrangements can be found in the references identified above.

[0065] In one embodiment, an electric current is emitted by electrodes 826 on the leads to stimulate nerve fibers, muscle fibers, or other body tissues near the electrical stimulation system. A processor 804 is typically included to control the timing and electrical characteristics of the electrical stimulation system. For example, if necessary, the processor 804 can control one or more of the timing, frequency, intensity, duration, and waveform of the pulses. In addition, the processor 804 can select which electrodes can be used to provide stimulation, if necessary. In some embodiments, the processor 804 selects which electrode(s) is the cathode and which electrode(s) is the anode. In some embodiments, the processor 804 is used to identify which electrodes provide the most useful stimulation to the desired tissue.

[0066] Any processor may be used, and it may be as simple as, for example, an electronic device that generates pulses at regular intervals, or the processor may be capable of receiving and interpreting instructions from, for example, an external programming unit 808 that allows modification of pulse characteristics. In the embodiment shown, the processor 804 is coupled to a receiver 802, which in turn is coupled to an optional antenna 818. This allows the processor 804 to receive instructions from an external source to, for example, direct pulse characteristics and selection of electrodes, if desired.

[0067] In one embodiment, the antenna 818 is capable of receiving signals (e.g., RF signals) from an external telemetry unit 806 that is programmed by a programming unit 808. The programming unit 808 may be external to the telemetry unit 806, or may be part of the telemetry unit 806. The telemetry unit 806 may be a device worn on the user's skin, or may be carried by the user, and may have a form similar to a pager, a cellular phone, or a remote control if desired. As another alternative, the telemetry unit 806 may not be worn or carried by the user, but may be available only at a home station or a clinician's office. The programming unit 808 may be any unit capable of providing information to the telemetry unit 806 for transmission to the electrical stimulation system 800. The programming unit 808 may be part of the telemetry unit 806, or may provide signals or information to the telemetry unit 806 via a wireless or wired connection. An example of a suitable programming unit may be a computer operated by a user or clinician to send signals to the telemetry unit 806.

[0068] Signals sent to the processor 804 via the antenna 818 and the receiver 802 can be used to modify or otherwise direct the operation of the electrical stimulation system. For example, the signals can be used to modify the pulses of the electrical stimulation system, such as modifying one or more of the pulse duration, pulse frequency, pulse waveform, and pulse intensity. These signals can also direct the electrical stimulation system 800 to stop operating, start operating, start charging the battery, or stop charging the battery. In other embodiments, the stimulation system does not include the antenna 818 or the receiver 802, and the processor 804 operates as programmed.

[0069] Optionally, the electrical stimulation system 800 can include a transmitter (not shown) coupled to the processor 804 and the antenna 818 for transmitting signals back to the telemetry unit 806 or another unit capable of receiving the signals. For example, the electrical stimulation system 800 can transmit a signal indicating whether the electrical stimulation system 800 is operating properly or indicating when the battery needs to be charged or the amount of power remaining in the battery. The processor 804 can also transmit information about the characteristics of the pulses so that a user or clinician can determine or verify the characteristics.

[0070] The above specification provides a description of the making and using of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.

Claims

1. A system for generating stimulation parameters for delivering stimulation through at least one of a plurality of electrodes (26) of an implanted lead (12), comprising: a non-transitory memory (574) having instructions stored thereon; as well as a processor (572) coupled to the memory and configured to execute the instructions, the instructions comprising: receiving information regarding at least one of: i) an electrical response of patient tissue; ii) a patient response to stimulation; or iii) a placement of an implanted lead or an electrode of an implanted lead relative to anatomy of the patient; and Electrode weights are calculated individually for each of the multiple electrodes of the implanted lead based on the received information.

2. A system according to claim 1, wherein the electrical response of the patient tissue includes at least one characteristic of the electrical response to at least one electrical pulse delivered to the patient tissue by at least one of the electrodes of the implanted lead.

3. The system of claim 1, wherein the electrical response of the patient tissue comprises an electrogram (ESG) or at least one characteristic of an ESG.

4. A system according to claim 3, wherein the electrical response of the patient tissue includes at least one of the following: the area under the curve of the ESG, the range of the amplitude of the curve in a defined time window, the length of the curve of the ESG, the energy content of the ESG, the range of the derivative of the ESG in a predetermined time window, the time delay of a specified signal peak of the ESG, the power of the ESG in a predetermined frequency band, the change in the frequency with the highest energy in the ESG in a predetermined frequency band, the coherence change in the ESG, the quality factor of the specified signal peak of the ESG in a predetermined time window, or the half-width of a specific signal peak of the ESG in a predetermined time window.

5. The system of claim 1, wherein the patient response to the stimulation comprises at least one of patient feedback, clinician feedback, signals from one or more sensors, or measurements based on signals from the one or more sensors.

6. A system according to claim 1, wherein the arrangement of the implanted lead or electrode relative to the patient anatomy includes the position of the implanted lead or electrode within the patient anatomy.

7. A system according to claim 6, wherein the position is determined based on imaging of the implanted lead or electrode within the patient's anatomy.

8. A system according to claim 1, wherein the arrangement of the implanted leads or electrodes relative to the patient's anatomy includes the lateral distance of the implanted leads or electrodes from the center, dorsal column or dorsal root of the patient's spinal cord and the longitudinal position along the patient's spinal cord.

9. A system according to claim 1, wherein the instructions further include using at least one of the electrode weights to generate simulation parameters for use with the implanted lead.

10. The system of claim 9, wherein generating stimulation parameters comprises using at least one of the electrode weights to generate an adjustment to a stimulation parameter previously used for use with the implanted lead. The system of claim 10 , wherein generating the adjustment comprises generating the adjustment in response to a manipulation instruction.

12. The system of claim 1, wherein the electrode weights are in the range of 0 to 1.

13. The system of claim 1, wherein receiving information comprises: delivering an electrical pulse using the electrode individually for each of the plurality of electrodes; and receiving an electrical response to the delivering, wherein the information is generated based on the received electrical response.

14. The system of claim 1, wherein the information is patient-specific information.

15. A non-transitory computer-readable medium having stored thereon instructions for execution by a processor, comprising: receiving patient-specific information regarding at least one of: i) an electrical response of a patient's tissue; ii) the patient's response to the stimulus; or iii) the placement of the implanted lead (12) or the electrode (26) of the implanted lead relative to the patient's anatomy; as well as Electrode weights are calculated individually for each of the multiple electrodes of the implanted lead based on the received information.

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