The present application claims priority from Australian Provisional Patent Application No. 2022902068 filed on Jul. 23, 2022, the contents of which are incorporated herein by reference in their entirety.
The present invention relates to neural stimulation therapy and in particular to systems and methods for improved programming of neural stimulation therapy assisted by virtual reality/augmented reality devices.
There are a range of situations in which it is desirable to apply neural stimuli in order to alter neural function, a process known as neuromodulation. For example, neuromodulation is used to treat a variety of disorders including chronic neuropathic pain, Parkinson's disease, and migraine. A neuromodulation device applies an electrical pulse (stimulus) to neural tissue (fibres, or neurons) in order to generate a therapeutic effect. In general, the electrical stimulus generated by a neuromodulation device evokes a neural response known as an action potential in a neural fibre which then has either an inhibitory or excitatory effect. Inhibitory effects can be used to modulate an undesired process such as the transmission of pain, or excitatory effects may be used to cause a desired effect such as the contraction of a muscle.
When used to relieve neuropathic pain originating in the trunk and limbs, the electrical pulse is applied to the dorsal column (DC) of the spinal cord, a procedure referred to as spinal cord stimulation (SCS). Such a device typically comprises an implanted electrical pulse generator, and a power source such as a battery that may be transcutaneously rechargeable by wireless means, such as inductive transfer. An electrode array is connected to the pulse generator, and is implanted adjacent the target neural fibre(s) in the spinal cord, typically in the dorsal epidural space above the dorsal column. An electrical pulse of sufficient intensity applied to the target neural fibres by a stimulus electrode causes the depolarisation of neurons in the fibres, which in turn generates an action potential in the fibres. Action potentials propagate along the fibres in orthodromic (in afferent fibres this means towards the head, or rostral) and antidromic (in afferent fibres this means towards the cauda, or caudal) directions. Action potentials propagating along Aβ (A-beta) fibres being stimulated in this way inhibit the transmission of pain from a region of the body innervated by the target neural fibres (the dermatome) to the brain. To sustain the pain relief effects, stimuli are applied repeatedly, for example at a frequency in the range of 30 Hz-100 Hz.
For effective and comfortable neuromodulation, it is necessary to maintain stimulus intensity above a recruitment threshold. Stimuli below the recruitment threshold will fail to recruit sufficient neurons to generate action potentials with a therapeutic effect. In almost all neuromodulation applications, response from a single class of fibre is desired, but the stimulus waveforms employed can evoke action potentials in other classes of fibres which cause unwanted side effects. In pain relief, it is therefore desirable to apply stimuli with intensity below a discomfort threshold, above which uncomfortable or painful percepts arise due to over-recruitment of Aβ fibres. When recruitment is too large, Aβ fibres produce uncomfortable sensations. Stimulation at high intensity may even recruit Aδ (A-delta) fibres, which are sensory nerve fibres associated with acute pain, cold and heat sensation. It is therefore desirable to maintain stimulus intensity within a therapeutic range between the recruitment threshold and the discomfort threshold.
The task of maintaining appropriate neural recruitment is made more difficult by electrode migration (change in position over time) and/or postural changes of the implant recipient (patient), either of which can significantly alter the neural recruitment arising from a given stimulus, and therefore the therapeutic range. There is room in the epidural space for the electrode array to move, and such array movement from migration or posture change alters the electrode-to-fibre distance and thus the recruitment efficacy of a given stimulus. Moreover, the spinal cord itself can move within the cerebrospinal fluid (CSF) with respect to the dura. During postural changes, the amount of CSF and/or the distance between the spinal cord and the electrode can change significantly. This effect is so large that postural changes alone can cause a previously comfortable and effective stimulus regime to become either ineffectual or painful.
Attempts have been made to address such problems by way of feedback or closed-loop control, such as using the methods set forth in International Patent Publication No. WO2012/155188 by the present applicant. Feedback control seeks to compensate for relative nerve/electrode movement by controlling the intensity of the delivered stimuli so as to maintain a substantially constant neural recruitment. The intensity of a neural response evoked by a stimulus may be used as a feedback variable representative of the amount of neural recruitment. A signal representative of the neural response may be sensed by a measurement electrode in electrical communication with the recruited neural fibres, and processed to obtain the feedback variable. Based on the response intensity, the intensity of the applied stimulus may be adjusted to maintain the response intensity within a therapeutic range.
It is therefore desirable to accurately measure the intensity and other characteristics of a neural response evoked by the stimulus. The action potentials generated by the depolarisation of a large number of fibres by a stimulus sum to form a measurable signal known as an evoked compound action potential (ECAP). Accordingly, an ECAP is the sum of responses from a large number of single fibre action potentials. The ECAP generated from the depolarisation of a group of similar fibres may be measured at a measurement electrode as a positive peak potential, then a negative peak, followed by a second positive peak. This morphology is caused by the region of activation passing the measurement electrode as the action potentials propagate along the individual fibres.
Approaches proposed for obtaining a neural response measurement are described by the present applicant in International Patent Publication No. WO2012/155183, the content of which is incorporated herein by reference.
Closed-loop neural stimulation therapy is governed by a number of parameters to which values must be assigned to implement the therapy. The effectiveness of the therapy depends in large measure on the suitability of the assigned parameter values to the patient undergoing the therapy. As patients vary significantly in their physiological characteristics, a “one-size-fits-all” approach to parameter value assignment is likely to result in ineffective therapy for a large proportion of patients. An important preliminary task, once a neuromodulation device has been implanted in a patient, is therefore to assign values to the therapy parameters that maximise the effectiveness of the therapy the device will deliver to that particular patient. This task is known as programming or fitting the device. Programming generally involves applying certain test stimuli via the device, recording responses, and based on the recorded responses, inferring or calculating the most effective parameter values for the patient. The resulting parameter values are then formed into a “program” that may be loaded to the device to govern subsequent therapy. Some of the recorded responses may be neural responses evoked by the test stimuli, which provide an objective source of information that may be analysed. Obtaining patient feedback about their sensations in response to the test stimuli is also important during programming of closed-loop neural stimulation therapy. However, mediation between patients and the programming system by trained clinical engineers is expensive and time-consuming.
Moreover, thresholds for discomfort vary widely between patients, between postures for a single patient, and between stimulus electrodes for a given patient in a given posture. It is difficult to know in advance where a given patient's discomfort threshold is in a given posture. The result is that a test stimulus of an intensity that is comfortable for one patient may provoke acute discomfort for another patient, or for the same patient in a different posture, or for the same patient in the same posture when applied at a different stimulus electrode. This complicates certain aspects of programming involving measurement of the intensity of patients' neural responses across the full comfortable range of stimulus intensity at a particular stimulus electrode.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
In this specification, a statement that an element may be “at least one of” a list of options is to be understood to mean that the element may be any one of the listed options, or may be any combination of two or more of the listed options.
Disclosed herein is a programming system for a neuromodulation device that is assisted by virtual reality (VR)/augmented reality (AR) functionality. The VR/AR-assisted programming system renders virtual objects to the field of view of the patient wearing a VR/AR headset. The patient may interact with the virtual objects to either control and adjust parameters of test stimuli being delivered in real time, or provide feedback about the sensations they are experiencing either before or as a result of the test stimuli being delivered. Alternatively, or additionally, a posture sensor forming part of the VR/AR equipment may detect a (static or dynamic) posture of the patient, so that currently estimated patient characteristics that are posture-dependent may be associated with the currently detected posture. Alternatively, or additionally, the VR/AR environment may prompt the patient to assume a posture, so that currently estimated patient characteristics that are posture-dependent may be associated with the currently prompted posture.
According to a first aspect of the present technology, there is provided a neurostimulation system comprising: a neuromodulation device for controllably delivering neural stimuli; a headset configured to be worn by the patient and to display images of a virtual object to the patient; one or more sensors configured to perceive a gesture of the patient; and an external computing device. The neuromodulation device comprises: a plurality of implantable electrodes; a stimulus source configured to deliver neural stimuli via one or more of the implantable electrodes to a neural pathway of a patient; and a control unit configured to control the stimulus source to deliver each neural stimulus according to one or more stimulus parameters. The external computing device comprises a processor in communication with the neuromodulation device, the headset, and the one or more sensors. The processor is configured to: instruct the control unit to control the stimulus source to deliver a neural stimulus according to the one or more stimulus parameters; transmit the virtual object to the headset for display to the patient; receive information indicative of a gesture of the patient from the one or more sensors; and convert the information indicative of the gesture to a manipulation of the virtual object.
According to a second aspect of the present technology, there is provided an automated method of controllably delivering a neural stimulus to a patient. The method comprises: delivering neural stimuli to a patient according to one or more stimulus parameters; rendering a virtual object to images for display to the patient via a headset configured to be worn by the patient and to display images of a virtual object to the patient; receiving information indicative of a gesture of the patient via one or more sensors configured to perceive a gesture of the patient; and converting the information indicative of the gesture to a manipulation of the virtual object.
According to a third aspect of the present technology, there is provided a neurostimulation system comprising a neuromodulation device for controllably delivering neural stimuli; a posture sensor configured to detect a posture of the patient; and an external computing device. The neuromodulation device comprises: a plurality of implantable electrodes; a stimulus source configured to deliver neural stimuli via one or more of the implantable electrodes to a neural pathway of a patient; and a control unit configured to control the stimulus source to deliver each neural stimulus according to one or more stimulus parameters. The external computing device comprises a processor in communication with the neuromodulation device and the posture sensor. The processor is configured to: instruct the control unit to control the stimulus source to deliver a neural stimulus according to the one or more stimulus parameters; receive information indicative of a detected posture of the patient from the posture sensor; and store data related to the neural stimuli in association with the information indicative of the detected posture.
According to a fourth aspect of the present technology, there is provided an automated method of controllably delivering a neural stimulus to a patient. The method comprises: delivering neural stimuli to a patient according to one or more stimulus parameters; receiving information indicative of a detected posture of the patient from a posture sensor configured to detect a posture of the patient; and storing data related to the neural stimuli in association with the information indicative of the detected posture.
According to a fifth aspect of the present technology, there is provided a neurostimulation system comprising: a neuromodulation device for controllably delivering neural stimuli; a headset configured to be worn by the patient and to display a virtual object to the patient; and an external computing device. The neuromodulation device comprises: a plurality of implantable electrodes; a stimulus source configured to deliver neural stimuli via one or more of the implantable electrodes to a neural pathway of a patient; and a control unit configured to control the stimulus source to deliver each neural stimulus according to one or more stimulus parameters. The external computing device comprises a processor in communication with the neuromodulation device and the headset. The processor is configured to: instruct the control unit to control the stimulus source to deliver a neural stimulus according to the one or more stimulus parameters; transmit the virtual object to the headset, the virtual object configured to prompt the patient to assume a first posture; and store data related to the neural stimuli in association with the first posture.
According to a sixth aspect of the present technology, there is provided an automated method of controllably delivering neural stimuli to a patient. The method comprises: delivering neural stimuli according to one or more stimulus parameters; rendering a virtual object to images for display to the patient via a headset so as to prompt the patient to assume a first posture, the headset being configured to be worn by the patient and to display images of a virtual object to the patient; and storing data related to the neural stimuli in association with the first posture.
References herein to estimation, determination, comparison and the like are to be understood as referring to an automated process carried out on data by a processor operating to execute a predefined procedure suitable to effect the described estimation, determination and/or comparison step(s). The technology disclosed herein may be implemented in hardware (e.g., using digital signal processors, application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs)), or in software (e.g., using instructions tangibly stored on non-transitory computer-readable media for causing a data processing system to perform the steps described herein), or in a combination of hardware and software. The disclosed technology can also be embodied as computer-readable code on a computer-readable medium. The computer-readable medium can include any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer-readable medium include read-only memory (“ROM”), random-access memory (“RAM”), magnetic tape, optical data storage devices, flash storage devices, or any other suitable storage devices. The computer-readable medium can also be distributed over network-coupled computer systems so that the computer-readable code is stored and/or executed in a distributed fashion.
One or more implementations of the invention will now be described with reference to the accompanying drawings, in which:
Numerous aspects of the operation of implanted stimulator 100 may be programmable by an external computing device 192, which may be operable by a user such as a clinician or the patient 108. Moreover, implanted stimulator 100 serves a data gathering role, with gathered data being communicated to external device 192 via a transcutaneous communications channel 190. Communications channel 190 may be active on a substantially continuous basis, at periodic intervals, at non-periodic intervals, or upon request from the external device 192. External device 192 may thus provide a clinical interface configured to program the implanted stimulator 100 and recover data stored on the implanted stimulator 100. This configuration is achieved by program instructions collectively referred to as the Clinical Programming Application (CPA) and stored in an instruction memory of the clinical interface.
Delivery of an appropriate stimulus via stimulus electrodes 2 and 4 to the nerve 180 evokes a neural response 170 comprising an evoked compound action potential (ECAP) which will propagate along the nerve 180 as illustrated at a rate known as the conduction velocity. The ECAP may be evoked for therapeutic purposes, which in the case of a spinal cord stimulator for chronic pain may be to create paraesthesia at a desired location. To this end, the stimulus electrodes 2 and 4 are used to deliver stimuli periodically at any therapeutically suitable frequency, for example 30 Hz, although other frequencies may be used including frequencies as high as the kHz range. In alternative implementations, stimuli may be delivered in a non-periodic manner such as in bursts, or sporadically, as appropriate for the patient 108. To program the stimulator 100 to the patient 108, a clinician may cause the stimulator 100 to deliver stimuli of various configurations which seek to produce a sensation that is experienced by the user as paraesthesia. When a stimulus electrode configuration is found which evokes paraesthesia in a location and of a size which is congruent with the area of the patient's body affected by pain and of a quality that is comfortable for the patient, the clinician or the patient nominates that configuration for ongoing use. The program parameters may be loaded into the memory 118 of the stimulator 100 as the clinical settings 121.
The ECAP may be recorded differentially using two measurement electrodes, as illustrated in
The ECAP 600 may be characterised by any suitable characteristic(s) of which some are indicated in
Returning to
Signals sensed by the measurement electrodes 6, 8 and processed by measurement circuitry 128 are further processed by an ECAP detector implemented within controller 116, configured by control programs 122, to obtain information regarding the effect of the applied stimulus upon the nerve 180. In some implementations, the sensed signals are processed by the ECAP detector in a manner which measures and stores one or more characteristics from each evoked neural response or group of evoked neural responses contained in the sensed signal. In one such implementation, the characteristics comprise a peak-to-peak ECAP amplitude in microvolts (μV). For example, the sensed signals may be processed by the ECAP detector to determine the peak-to-peak ECAP amplitude in accordance with the teachings of International Patent Publication No. WO2015/074121, the contents of which are incorporated herein by reference. Alternative implementations of the ECAP detector may measure and store an alternative characteristic from the neural response, or may measure and store two or more characteristics from the neural response.
Stimulator 100 applies stimuli over a potentially long period such as days, weeks, or months and during this time may store characteristics of neural responses, clinical settings, paraesthesia target level, and other operational parameters in memory 118. To effect suitable SCS therapy, stimulator 100 may deliver tens, hundreds or even thousands of stimuli per second, for many hours each day. Each neural response or group of responses generates one or more characteristics such as a measure of the intensity of the neural response. Stimulator 100 thus may produce such data at a rate of tens or hundreds of Hz, or even kHz, and over the course of hours or days this process results in large amounts of clinical data 120 which may be stored in the memory 118. Memory 118 is however necessarily of limited capacity and care is thus required to select compact data forms for storage into the memory 118, to ensure that the memory 118 is not exhausted before such time that the data is expected to be retrieved wirelessly by external device 192, which may occur only once or twice a day, or less.
An activation plot, or growth curve, is an approximation to the relationship between stimulus intensity (e.g. an amplitude of the current pulse 160) and intensity of neural response 170 evoked by the stimulus (e.g. an ECAP amplitude).
where s is the stimulus intensity, y is the ECAP amplitude, T is the ECAP threshold and S is the slope of the activation plot (referred to herein as the patient sensitivity). The sensitivity S and the ECAP threshold T are the key parameters of the activation plot 402.
For effective and comfortable operation of an implantable neuromodulation device such as the stimulator 100, it is desirable to maintain stimulus intensity within a therapeutic range. A stimulus intensity within a therapeutic range 412 is above the ECAP threshold 404 and below the discomfort threshold 408. In principle, it would be straightforward to measure these limits and ensure that stimulus intensity, which may be closely controlled, always falls within the therapeutic range 412. However, the activation plot, and therefore the therapeutic range 412, varies with the posture of the patient 108.
To keep the applied stimulus intensity within the therapeutic range as patient posture varies, in some implementations an implantable neuromodulation device such as the stimulator 100 may adjust the applied stimulus intensity based on a feedback variable that is determined from one or more measured ECAP characteristics. In one implementation, the device may adjust the stimulus intensity to maintain the measured ECAP amplitude at a target response intensity. For example, the device may calculate an error between a target ECAP amplitude and a measured ECAP amplitude, and adjust the applied stimulus intensity to reduce the error as much as possible, such as by adding the scaled error to the current stimulus intensity. A neuromodulation device that operates by adjusting the applied stimulus intensity based on a measured ECAP characteristic is said to be operating in closed-loop mode and will also be referred to as a closed-loop neural stimulation (CLNS) device. By adjusting the applied stimulus intensity to maintain the measured ECAP amplitude at an appropriate target response intensity, such as an ECAP target 520 illustrated in
A CLNS device comprises a stimulator that takes a stimulus intensity value and converts it into a neural stimulus comprising a sequence of electrical pulses according to a predefined stimulation pattern. The stimulation pattern is parametrised by multiple stimulus parameters including stimulus amplitude, pulse width, number of phases, order of phases, number of stimulus electrode poles (two for bipolar, three for tripolar etc.), and stimulus rate or frequency. At least one of the stimulus parameters, for example the stimulus amplitude, is controlled by the feedback loop.
In an example CLNS system, a user (e.g. the patient or a clinician) sets a target response intensity, and the CLNS device performs proportional-integral-differential (PID) control. In some implementations, the differential contribution is disregarded and the CLNS device uses a first order integrating feedback loop. The stimulator produces stimulus in accordance with a stimulus intensity parameter, which evokes a neural response in the patient. The intensity of an evoked neural response (e.g. an ECAP) is detected, and its amplitude measured by the CLNS device and compared to the target response intensity.
The measured neural response intensity, and its deviation from the target response intensity, is used by the feedback loop to determine possible adjustments to the stimulus intensity parameter to maintain the neural response at the target intensity. If the target intensity is properly chosen, the patient receives consistently comfortable and therapeutic stimulation through posture changes and other perturbations to the stimulus/response behaviour.
The generated stimulus crosses from the electrodes to the spinal cord, which is represented in
The neural recruitment arising from the stimulus is affected by mechanical changes, including posture changes, walking, breathing, heartbeat and so on. Mechanical changes may cause impedance changes, or changes in the location and orientation of the nerve fibres relative to the electrode array(s). As described above, the intensity of the evoked response provides a measure of the recruitment of the fibres being stimulated. In general, the more intense the stimulus, the more recruitment and the more intense the evoked response. An evoked response typically has a maximum amplitude in the range of microvolts, whereas the voltage resulting from the stimulus applied to evoke the response is typically several volts.
Measurement circuitry 318, which may be identified with measurement circuitry 128, amplifies the sensed signal r (including evoked neural response, artefact, and measurement noise), and samples the amplified sensed signal r to capture a “signal window” comprising a predetermined number of samples of the amplified sensed signal r. The ECAP detector 320 processes the signal window and outputs a measured neural response intensity d. A typical number of samples in a captured signal window is 60. In one implementation, the neural response intensity comprises a peak-to-peak ECAP amplitude. The measured response intensity d is input into the feedback controller 310. The feedback controller 310 comprises a comparator 324 that compares the measured response intensity d to the target ECAP amplitude as set by the target ECAP controller 304 and provides an indication of the difference between the measured response intensity d and the target ECAP amplitude. This difference is the error value, e.
The feedback controller 310 calculates an adjusted stimulus intensity parameter, s, with the aim of maintaining a measured response intensity d equal to the target ECAP amplitude. Accordingly, the feedback controller 310 adjusts the stimulus intensity parameter s to minimise the error value, e. In one implementation, the controller 310 utilises a first order integrating function, using a gain element 336 and an integrator 338, in order to provide suitable adjustment to the stimulus intensity parameter s. According to such an implementation, the current stimulus intensity parameter s may be determined by the feedback controller 310 as
s=∫Kedt (2)
where K is the gain of the gain element 336 (the controller gain). This relation may also be represented as
δs=Ke (3)
where δs is an adjustment to the current stimulus intensity parameter s.
A target ECAP amplitude is input to the feedback controller 310 via the target ECAP controller 304. In one embodiment, the target ECAP controller 304 provides an indication of a specific target ECAP amplitude. In another embodiment, the target ECAP controller 304 provides an indication to increase or to decrease the present target ECAP amplitude. The target ECAP controller 304 may comprise an input into the CLNS system 300, via which the patient or clinician can input a target ECAP amplitude, or indication thereof. The target ECAP controller 304 may comprise memory in which the target ECAP amplitude is stored, and from which the target ECAP amplitude is provided to the feedback controller 310.
A clinical settings controller 302 provides clinical settings to the system 300, including the feedback controller 310 and the stimulus parameters for the stimulator 312 that are not under the control of the feedback controller 310. In one example, the clinical settings controller 302 may be configured to adjust the controller gain K of the feedback controller 310 to adapt the feedback loop to patient sensitivity. The clinical settings controller 302 may comprise an input into the CLNS system 300, via which the patient or clinician can adjust the clinical settings. The clinical settings controller 302 may comprise memory in which the clinical settings are stored, and are provided to components of the system 300.
In some implementations, two clocks (not shown) are used, being a stimulus clock operating at the stimulus frequency (e.g. 60 Hz) and a sample clock for sampling the sensed signal r (for example, operating at a sampling frequency of 10 kHz). As the ECAP detector 320 is linear, only the stimulus clock affects the dynamics of the CLNS system 300. On the next stimulus clock cycle, the stimulator 312 outputs a stimulus in accordance with the adjusted stimulus intensity s. Accordingly, there is a delay of one stimulus clock cycle before the stimulus intensity is updated in light of the error value e.
The charger 750 is configured to recharge a rechargeable power source of the neuromodulation device 710. The recharging is illustrated as wireless in
The neuromodulation device 710 is wirelessly connected to a Clinical System Transceiver (CST) 730. The wireless connection may be implemented as the transcutaneous communications channel 190 of
The CI 740 may be implemented as the external computing device 192 of
As mentioned above, obtaining patient feedback about their sensations is important during programming of closed-loop neurostimulation, but mediation by trained clinical engineers is expensive and time-consuming. It would therefore be advantageous if patients could program their own implantable device themselves, or at least partly by themselves with reduced assistance from a clinician. However, interfaces for current programming systems are non-intuitive and generally unsuitable for direct use by patients because of their technical nature. There is therefore a need for a CPA to be as intuitive for non-technical users as possible while avoiding discomfort to the patient.
Implementations of an Assisted Programming System (APS) according to the present technology are generally configured to meet this need. In some implementations, the APS comprises two elements: the Assisted Programming Module (APM), which forms part of the CPA, and the Assisted Programming Firmware (APF), which forms part of the control programs 122 executed by the controller 116 of the electronics module 110. The data obtained from the patient is analysed by the APM to determine the parameters and settings for the neural stimulation therapy to be delivered by the stimulator 100. The APF is configured to complement the operation of the APM by responding to commands issued by the APM via the CST 730 to the stimulator 100 to deliver specified stimuli to the patient, and by returning, via the CST 730, measurements of neural responses to the delivered stimuli.
In other implementations, all the processing of the APS according to the present technology is done by the APF. In other words, the data obtained from the patient is not passed to the APM, but is analysed by the APF to determine the parameters and settings for the neural stimulation therapy to be delivered by the stimulator 100.
In implementations of the APS in which the APM analyses the data from the patient, the APS instructs the device 710 to capture and return signal windows to the CI 740 via the CST 730. In such implementations, the device 710 captures the signal windows using the measurement circuit 128 and bypasses the ECAP detector 320, storing the data representing the raw signal windows temporarily in memory 118 before transmitting the data representing the captured signal windows to the APS for analysis.
Following the programming, the APS may load the determined program onto the device 710 to govern subsequent neurostimulation therapy. In one implementation, the program comprises clinical settings 121, also referred to as therapy parameters, that are input to the neuromodulation device by, or stored in, the clinical settings controller 302. The patient may subsequently control the device 710 to deliver the therapy according to the determined program using the remote controller 720 as described above. In one implementation, the remote controller 720 may control the target ECAP amplitude for the CLNS system 300 via the input to the target ECAP controller 304. The determined program may also, or alternatively, be loaded into the CPA for validation and modification.
The patient 805 is wearing a headset 815. The headset 815 is principally a display device configured to display images in front of the eyes of the patient 805. In some implementations, the headset 815 is configured to display separate stereoscopic images to each eye of the patient 805 to give the patient 805 the illusion of a virtual three-dimensional (3D) environment containing virtual 3D objects. The headset 815 is in communication with a VR/AR computing device 830 from which it receives instructions as to what images to display to the eyes of the patient 805. The communication may be wired, as illustrated in
The VR/AR-assisted programming system (APS) 800 may also comprise an additional headset (not shown) that may be worn by a clinician (not shown) assisting the patient 805 in the programming. The additional headset may replicate the view that is shown to the patient 805 by the headset 815 so that the clinician may assist the patient 805 more easily. Alternatively, the additional headset may display a view of the same virtual environment as the patient 805, in the same way as the headset 815, except from a viewpoint that is unique to the assisting clinician.
Virtual Reality (VR) and Augmented Reality (AR) are related terms that differ only in degree of immersivity, in that VR systems are generally more immersive than AR systems. VR systems immerse the user in a fully-rendered virtual environment containing no elements of actual reality perceivable by the user. AR systems, by contrast, meld virtual objects into a view of the actual environment around the patient. For AR systems, therefore, the headset 815 is configured with some degree of transparency to allow the patient 805 to view the actual environment. The headset 815 for VR systems, by contrast, is sufficiently opaque to substantially prevent the patient 805 from viewing the actual environment around the patient.
Room sensors 840a and 840b are configured to track the position and orientation of the headset 815. As the patient 805 moves his or her head, the headset 815 moves along with the head, and this movement of the headset 815 is tracked by the room sensors 840a and 840b. The room sensors 840a and 840b are in communication with the VR/AR computing device 830, which receives information representing the position and orientation of the headset 815 from the room sensors 840a and 840b from time to time. As the position and orientation of the headset 815 changes, the VR/AR computing device 830 alters the images transmitted to the headset 815 to simulate the effect of those changes on the patient's view of the virtual objects or environment being rendered. The effect is that the patient 805 perceives changes to their view of the virtual objects or environment that are consistent with the manner in which they have moved their head, just as a person's view of their actual environment changes as they move their head. This dynamic rendering dramatically increases the immersivity of the VR/AR system.
The patient 805 may hold one or more handheld controllers, in
Also forming part of the VR/AR APS 800 is a posture sensor 850. The posture sensor 850 is configured to sense the position and posture of the patient's body. The posture sensor 850 is in communication with the VR/AR computing device 830, to which the posture sensor 850 transmits information representing the position and posture of the patient's body. The VR/AR computing device 830 may analyse the information to detect a dynamic activity of the patient, such as walking, as well as a static posture, such as sitting. The term “posture” in the present disclosure may therefore be read to include dynamic activity as well as static posture. The VR/AR computing device 830 may alter the images transmitted to the headset 815 based on the position and posture of the patient's body. In particular, as with the handheld controllers 820a and 820b, a representation of the patient's body 805 itself may be rendered using this information as a virtual object referred to as an “avatar”. The position and posture of the patient's avatar in the virtual environment correspond to the position and posture of the patient's body in the actual environment.
In some implementations of the VR/AR APS 800 according to the present technology, the posture sensor 850 is configured to sense the position of the patient's hands in the same way that the room sensors 840a and 840b detect and track the positions of the handheld controllers 820a and 820b. This allows the patient to manipulate virtual objects without a need for the handheld controllers 820a and 820b nor sensors 840a and 840b.
In some implementations of the VR/AR APS 800 according to the present technology, the VR/AR computing device 830 is separate to, but in communication, with the CI 860. In other implementations of the VR/AR APS 800 according to the present technology, the VR/AR computing device 830 is integrated with the CI 860. In both implementations, the programming of the device 810 is carried out by the patient 805 through the CI 860 assisted by the VR/AR capability of the VR/AR computing device 830 and its ancillary devices: the headset 815, the room sensors 840a and 840b, the handheld controllers 820a and 820b, and the posture sensor 850.
According to the present technology, there are two principal functions of the VR/AR APS 800 that are assisted by the VR/AR capability: setting of therapy parameters (clinical settings); and providing feedback about the patient's condition or about sensations experienced during neural stimulation. Both of these functions may be accomplished by the performance of predefined gestures by the patient in relation to virtual objects in the virtual environment, possibly while assuming predefined postures.
According to one aspect of the present technology, the patient 805 may manipulate a virtual object to control one or more therapy parameters such as stimulus electrode configuration, stimulus intensity, stimulus frequency, and pulse width. If the device 810 is a CLNS device, the therapy parameters may also include feedback loop parameters such as controller gain and target ECAP amplitude. The manipulations of the virtual object, such as changes to its position, orientation, or shape, result in changes to corresponding parameters of the test stimuli being delivered to the patient by the implantable device 810 or the feedback loop being operated by the implantable device 810. The virtual object therefore acts as a virtual control for the multiple parameters controlling the test stimuli being delivered to the patient. The rationale for this aspect of the present technology is that a patient is potentially extremely fast at instinctively learning a transform of tactile and visual feedback into sensation (so-called sensory fusion) and so will rapidly learn how to adjust their therapy parameters to give optimal pain relief.
It is further contemplated that other manipulations of the virtual control 910 may affect other stimulus parameters. For example, a gesture to translate the virtual control 910 to a new 3D position within the virtual environment 900 comprises three independent parameters and therefore may be mapped to a change in each of three other stimulus parameters.
The virtual control 910 in some embodiments may not necessarily be rigid but may be deformable. In such implementations, another example of a manipulation of the virtual control 910 is to distend the virtual control along a vertical axis.
Manipulations of the virtual control 910 may be concatenated to achieve sequential adjustments of the corresponding stimulus parameters. In one example,
Another example of a manipulation of a deformable virtual control 910 is to compress the virtual control along a vertical axis.
The virtual control 910 may be locally as well as globally deformable. In such implementations, manipulations of the virtual control 910 may affect only local regions of the virtual control 910. Manipulations such as squashing in and drawing out of local regions of the virtual control transform the original spherical virtual object into an irregular “blob” such as illustrated in
In implementations according to this aspect, the CI 860 may set values for one or more therapy parameters once the patient is satisfied with the pain relief resulting from a particular combination of parameters. The patient may communicate their satisfaction to the CI 860 by activating a virtual “complete” control that may be rendered to the virtual environment in similar fashion to the rendering of the virtual control 910.
According to another aspect of the present technology, the patient 805 may manipulate a virtual object to provide feedback to the VR/AR APS 800 about either their own condition or the sensations being experienced in response to neural stimulation being delivered by the implantable device 810. In one such implementation, the virtual object is a human body.
In alternative implementations, the virtual human body to be touched for the above-described purposes may be the patient's own avatar rather than a separate virtual human body as illustrated in
In implementations according to this aspect, the CI 860 may determine one or more therapy parameters using the feedback about patient sensation obtained in this manner. In one example, if the location of the sensation being experienced by the patient matches the location of their painful area, the CI 860 may confirm the current SEC to form part of the therapy parameters for the patient.
According to another aspect of the present technology, the patient assumes a number of different postures in sequence, while the VR/AR APS 800 delivers test stimuli and processes the corresponding neural responses in each posture to obtain a patient characteristic. The patient characteristic may be stored in association with the posture. For example, the test stimuli may be delivered with varying stimulus intensity, and the responses used to construct an activation plot describing the patient's response to test stimuli in each posture, as described above in relation to
In some implementations, the posture sensor 850 may be integrated with the clinical interface 860. In such implementations, the integrated posture sensor 850 may be a three-dimensional image capture apparatus. In such implementations, the clinical interface 860 may be a tablet computer or a smartphone equipped with such an integrated posture sensor.
In an alternative implementation, the VR/AR APS 800 may prompt or guide the patient to move between predefined postures, by asking the patient to interact with virtual objects that are rendered in specific places in the virtual environment corresponding to respective predefined postures. For example, the patient may be prompted to look at a virtual object rendered at the extreme left of their visual field. The patient will naturally turn their head to the left to do so, allowing test stimuli to be delivered and measurements of neural responses to be made in this posture. In another example, asking the patient to pick up a virtual object rendered on the ground at the patient's feet may prompt the patient to assume a crouching posture. Other virtual object positions corresponding to other postures may be contemplated. The implementations according to this aspect enable the programming to take place with less prescriptive involvement of the clinician.
As mentioned above, discomfort thresholds vary widely between patients, between postures for a single patient, and between stimulus electrode configurations (SECs) for a given patient in a given posture. It is difficult to know in advance where a given patient's discomfort threshold is for a given SEC in a given posture. The result is that a test stimulus of an intensity that is comfortable for one patient may provoke acute discomfort for another patient, or for the same patient in a different posture, or for the same patient in the same posture when applied at a different SEC. This means the measurement of the intensity of patients' neural responses across the therapeutic range of stimulus intensity at a particular SEC, as ideally would be performed to obtain the activation plot for that SEC, is liable to cause discomfort if carried out without either prior knowledge of the therapeutic range or real-time patient feedback.
According to another aspect of the present technology, the immersive effect of VR/AR may be utilised by the VR/AR APS 800 to modulate the attention of the patient away from their neural sensations while test stimuli are being delivered. According to this aspect, the VR/AR APS 800 may push back the actual threshold of discomfort, allowing a broader range of intensity of the test stimuli to be delivered without causing discomfort. A more accurate construction of the activation plots across different postures may thereby be obtained than are practical by conventional means. In one implementation, as the patient assumes each posture (either spontaneously or guided by the VR/AR APS 800, as described above), the VR/AR APS 800 renders soothing or engaging imagery and music to the patient while delivering the test stimuli and analysing the responses in coordination with the patient's detected postures as described above. In another such implementation, the VR/AR APS 800 engages the patient in a simple game requiring some movement and posture change to accomplish game objectives, while delivering the test stimuli and analysing the responses in coordination with the patient's detected postures as described above. One example of such a game is virtual dodge-ball. Such an implementation has the following beneficial effects:
According to another aspect of the present technology, the VR/AR APS 800 renders an animated virtual assistant to guide the patient 805 through a workflow of programming the device 810 with suitable therapy parameters for their particular condition and anatomy. Such a programming workflow is disclosed, for example, in International Patent Application no. PCT/AU2022/051556 by the present applicant, the contents of which are hereby incorporated by reference. The animated virtual assistant is configured to speak the guiding instructions at each stage of the workflow and to respond to any spoken queries by the patient.
It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not limiting or restrictive.
Number | Date | Country | Kind |
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2022902068 | Jul 2022 | AU | national |