Dormant implantable medical device

Abstract

Presented herein are techniques for providing a low-power implantable medical device that remains dormant until treatment is initiated. Start-up of the low-power implant can be initiated by emitting a signal from an external device. The techniques presented herein can provide on- demand stimulation for tinnitus suppression.

Description

DORMANT IMPUANTABUE MEDICAU DEVICEBACKGROUNDField of the Invention[oooi] The present invention relates generally to a low-power implantable medical device that remains dormant until treatment is initiated.Related Art

[0002] Medical devices have provided a wide range of therapeutic benefits to recipients over recent decades. Medical devices can include internal or implantable components / devices, external or wearable components / devices, or combinations thereof (e.g., a device having an external component communicating with an implantable component). Medical devices, such as traditional hearing aids, partially or fully-implantable hearing prostheses (e.g., bone conduction devices, mechanical stimulators, cochlear implants, etc.), pacemakers, defibrillators, functional electrical stimulation devices, and other medical devices have been successful in performing lifesaving and / or lifestyle enhancement functions and / or recipient monitoring for a number of years.

[0003] The types of medical devices and the ranges of functions performed thereby have increased over the years. For example, many medical devices, sometimes referred to as “implantable medical devices,” now often include one or more instruments, apparatus, sensors, processors, controllers or other functional mechanical or electrical components that are permanently or temporarily implanted in a recipient. These functional devices are typically used to diagnose, prevent, monitor, treat, or manage a disease / injury or symptom thereof, or to investigate, replace or modify the anatomy or a physiological process. Many of these functional devices utilize power and / or data received from external devices that are part of, or operate in conjunction with, implantable components.SUMMARY

[0004] In one aspect, a system is provided. The system comprises: an implantable neurostimulator with a rechargeable power source; and an external charger configured to charge the rechargeable power source, wherein the implantable neurostimulator is configured to enter a dormant state when the external charger is removed after charging the rechargeable power source, and to remain in the dormant state until receipt of a user command.

[0005] In another aspect, an implantable device is provided. The implantable device comprises: a rechargeable power source and an electronic assembly housed within a hermetic enclosure, wherein the electronic assembly is configured to charge the rechargeable power source with power received transcutaneously from a charger device; and a stimulating electrode connected to the electronic assembly via a feedthrough in the hermetic enclosure, wherein the stimulating electrode is configured to deliver electrical stimulation to a recipient of the implantable device, wherein the implantable device is configured to concurrently charge the rechargeable power source and deliver electrical stimulation to the recipient with power received transcutaneously from the charger device, and to automatically stop delivering electrical stimulation to the recipient when the implantable device ceases to receive power from the charger device.

[0006] In another aspect, an implantable neurostimulator is provided. The implantable neurostimulator comprises: a rechargeable power source; an electronic assembly configured to charge the rechargeable power source with power received transcutaneously from a charger device; and a passive telemetry circuit, wherein the implantable neurostimulator is configured to connect the rechargeable power source to the electronic assembly responsive to the passive telemetry circuit receiving a signal from an external device.

[0007] In another aspect, an implantable neurostimulator is provided. The implantable neurostimulator comprises: a rechargeable power source; and a passive telemetry circuit, wherein the implantable neurostimulator is configured to initiate electrical stimulation of a recipient of the implantable neurostimulator, using power stored in the rechargeable power source to create the electrical stimulation, responsive to the passive telemetry circuit receiving a signal from an external device.

[0008] In yet another aspect, a method is provided. The method comprises: receiving, at an implantable device, a power signal from a charger device for charging a rechargeable power source of the implantable device in a charging state; and automatically entering a first power state, by disconnecting the rechargeable power source from stimulation circuitry and monitoring circuitry of the implantable device, based on failure to receive the power signal from the charger device, wherein the first power state is a dormant state.

[0009] In another example, an implantable device is provided. The implantable device comprises: a first wireless circuit, wherein the first wireless circuit is configured to receive first wireless signals transmitted through the skin of a recipient in a first frequency band from a firstexternal device; and a second wireless circuit, wherein the second wireless circuit is configured to receive second wireless signals transmitted through the skin of the recipient in a second frequency band from a second external device; wherein the implantable device is configured to automatically transition from a first state to a second state responsive to the first wireless circuit receiving the first wireless signals, and to automatically transition from the first state to a third state responsive to the second wireless circuit receiving the second wireless signals.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Embodiments of the present invention are described herein in conjunction with the accompanying drawings, in which:

[0011] FIG. 1A is a schematic diagram illustrating an implant system including an implantable device, a charger device, and an external device, in accordance with certain embodiments presented herein;

[0012] FIG. IB is a side view of a recipient wearing the charger device of the implant system of FIG. 1A;

[0013] FIG. 2A is a diagram illustrating receipt of a power signal from a charger device at an implantable device of an implant system, in accordance with certain embodiments presented herein;

[0014] FIG. 2B is a diagram illustrating removal of the charger device from the presence of the implantable device of the implant system of FIG. 2A;

[0015] FIG. 2C is a diagram illustrating receipt of a wake-up signal from an external device at the implantable device of the implant system of FIG. 2A;

[0016] FIG. 3 is a flow diagram illustrating a series of operations performed at the charger device and the implantable device of FIG. 2A, in accordance with certain embodiments presented herein;

[0017] FIG. 4 is a flowchart of an example method for automatically transitioning an implantable medical device from an active state to a dormant state, in accordance with certain embodiments presented herein;

[0018] FIG. 5 is a flowchart of an example method for automatically transitioning an implantable medical device from a dormant state to an active state, , in accordance with certain embodiments presented herein;

[0019] FIGs. 6A, 6B, and 6C are diagrams illustrating a two-stage wake-up procedure of an implantable device, in accordance with certain embodiments presented herein;

[0020] FIG. 7 is a flowchart of an example method for implementing a two-stage wake-up procedure of an implantable device, in accordance with certain embodiments presented herein; and

[0021] FIG. 8 is a schematic diagram illustrating a vestibular stimulator system with which aspects of the techniques presented herein can be implemented.DETAILED DESCRIPTION

[0022] Tinnitus is the perception of noise or “ringing” in the ears, which currently affects an estimated 30 million people in the United States alone. Tinnitus is a common artefact of hearing loss, but can also be a symptom of other underlying conditions, such as ear injuries, circulatory system disorders, etc. Although tinnitus affects can range from mild to severe, almost one-quarter of those with tinnitus describe their tinnitus as disabling or nearly disabling.

[0023] It has recently been demonstrated that extra-cochlear electrical / current stimulation using, for example, an electrode placed on the promontory, or in a small (~0.5mm) bone bed made in the promontory, with the current delivered to the bone, can remediate tinnitus symptoms. In certain arrangements, the current is subthreshold (e.g., below a level that is perceptible to the recipient) without data encoding (e.g., simple recurring pulse train with fixed parameters, such as pulse width). In addition, it is believed that a substantial number of recipients can experience residual tinnitus inhibition following a period of electrical stimulation, meaning that continuous stimulation is not required for such recipients. For example, some recipients use the implant device for a period each morning and are tinnitus free for the rest of the day. Similar symptom inhibition has been observed in recipient’s undergoing other forms of electrical stimulation therapy. For example, vestibular implant recipients can experience temporary inhibition of balance disorders symptoms following a period of vestibular stimulation. Likewise, tibial nerve stimulation can produce residual inhibition of urinary urge incontinence.

[0024] For the above and other reasons, the inventors have discovered that the power requirements for a dedicated tinnitus therapy device are likely to be lower than for other, more full-featured implantable medical devices, such as cochlear implants. The result is that a small implant battery or super-capacitor can be used for on-demand stimulation for the treatment of tinnitus symptoms, without the need for an external component to trigger the stimulation. Accordingly, presented herein is a low-power implantable medical device that remains dormant until treatment is initiated. According to one aspect, start-up of the low-power implant can be initiated by emitting a wake-up signal from an external device, such as a mobile device (e.g., a smartphone, a tablet, etc.), for example. In certain embodiments, an implant system including the low-power implantable medical device is configured to enable on-demand stimulation for tinnitus suppression. That is, the techniques presented herein can deliver stimulation to provide therapeutic tinnitus relief to recipients on-demand (e.g., based on a user command) and / or on an as-needed basis (e.g., based on sensor outputs) via an implantable arrangement.

[0025] There are a number of different types of devices in / with which embodiments of the present invention may be implemented. Merely for ease of description, the techniques presented herein are primarily described with reference to a specific device in the form of a dedicated implantable tinnitus therapy device, which can be a “stand-alone” device or part of a tinnitus therapy device system. As used herein, a tinnitus therapy device is an implantable medical device having a primary purpose of providing tinnitus therapy / relief to a recipient. A stand-alone implantable tinnitus therapy device can be advantageous in that no external devices (e.g., a sound processing unit) are required, which makes the device aesthetically pleasing, comfortable, and enables the recipient’s ear canal to remain open for natural hearing. The stand-alone implantable tinnitus therapy device also enables around-the-clock therapy regimes, on-demand or on an as-needed or as-desired basis. However, it is to be appreciated that the techniques presented herein can be implemented by, or used in conjunction with, various other implantable medical devices. For example, the techniques presented herein can be used with other auditory prostheses, including but not limited to cochlear implants, bone conduction devices, middle ear auditory prostheses, direct acoustic stimulators, auditory brain stimulators, etc. The techniques presented herein can also be used with vestibular devices (e.g., vestibular implants), implantable sensors, drug delivery systems, functional electrical stimulation devices, seizure devices (e.g., devices for monitoring and / or treating epileptic events), sleep apnea devices, etc.

[0026] FIGs. 1A and IB illustrate an example implant system 100 with which aspects of the techniques presented herein can be implemented. The implant system 100 comprises a charger device 105 configured to be directly or indirectly attached to the body of the user, and an intemal / implantable component 112 configured to be implanted in the head of the user (i.e., under the skin / tissue of the recipient). In the examples of FIGs. 1A-1B, the implantable device 112 is sometimes referred to as an “implantable neurostimulator” or an “implantable tinnitus therapy device.” FIG. 1A illustrates the implantable device 112 implanted in the head 154 of a user, while FIG. IB illustrates the charger device 105 worn on the head 154 of the user. For ease of description, FIGs. 1A-1B will generally be described together.

[0027] In the example of FIGs. 1A-1B, the charger device 105 comprises an external coil (not shown in FIGs. 1A-1B, refer to external coil 208 of FIG. 2A) and an external magnet 148 fixed relative to the external coil, and the charger device 105 is configured to send power to the implantable device 112. The implantable device 112 comprises an implantable coil (not shown in FIGs. 1A-1B, refer to implantable coil 214 of FIG. 2A) and an internal magnet 152 fixed relative to the implantable coil 114. In general, the charger device 105 is a component that is configured to be magnetically coupled to the head 154 of the user via the external magnet 148 and the internal magnet 152, and to be inductively coupled to the implantable device 112 via the external coil 108 and the implantable coil 114.

[0028] The external magnet 148 and the internal magnet 152 facilitate operational alignment of the external coil 108 with the implantable coil 114. This operational alignment of the coils enables the charger device 105 to transmit power to the implantable device 112 via a closely- coupled wireless link (not shown in FIGs. 1A-1B, refer to closely-coupled wireless link 250 of FIG. 2A) formed between the external coil 108 and the implantable coil 114. In certain embodiments, the closely-coupled wireless link 150 is an RF link. However, various other types of energy transfer, such as infrared (IR), electromagnetic, capacitive, and / or inductive transfer may be used to transfer the power from the charger device 105 to the implantable device 112. After charging the internal power source of the implantable device 112 and removing the charger device 105, the implantable device 112 can operate independently from the charger device 105 to stimulate the user for at least a certain period of time.

[0029] In FIGs. 1A-1B, the implant system 100 is also shown with an external device 110, which is configured to implement certain other aspects of the techniques presented herein. The external device 110 can be a computing device, such as a personal computer (e.g., laptop, desktop, etc.), a mobile device (e.g., a smartphone, a tablet, etc.), or a remote -control unit (e.g.,a dedicated implant controller), for example. The external device 110 and the implantable device 112 wirelessly communicate via abi-directional communication link 180. For example, the bi-directional communication link 180 may comprise, for example, a short-range wireless communication link, such as a Bluetooth link, a Bluetooth Low Energy (BLE) link, a near-field communication (NFC) link, a radio frequency (RF) link, a cellular link, a proprietary link, etc. As described in further detail below, the external device 110 is configured to send data signals and / or user commands to the implantable device 112 using the bi-directional communication link 180, and the implantable device 112 can include a short-range wireless interface (e.g., Bluetooth, BLE, NFC, RF, etc.) for communication with the external device 110.

[0030] As noted, although the example embodiments set forth below are generally described in relation to tinnitus inhibition, the solutions described herein can also be applied to other treatment technologies (e.g., deep brain stimulation, vestibular stimulation, etc.). Also described below are various different scenarios for triggering operation of the low-power implantable medical device, regardless of what the issue is (i.e., not limited only to tinnitus). At least one of the particular trigger scenarios described below can result in near zero (or very low) power consumption.

[0031] A more detailed overview of an example implant system 200 (e.g., a tinnitus implant system) will now be provided with reference to FIGs. 2A, 2B, and 2C, which are block diagrams illustrating various functional components configured for implementing the techniques presented herein. Like the example implant system 100 of FIGs. 1A-1B, the implant system 200 of FIGs. 2A-2C comprises one or more implantable components and one or more external components, where like reference numbers referto like parts in both FIGs. 1A-1B and FIGs. 2A-2C (unless otherwise noted). In the specific examples of FIGs. 2A-2C, the one or more implantable components can be or include an implantable device 212 comprising a rechargeable power source 271 (e.g., a battery, a super-capacitor, etc.), a stimulation control circuit 273, a power circuit 275, and a passive telemetry circuit 277, which are all disposed in a hermetically -sealed housing. The housing operates as a protective barrier between the electrical components within the housing and the recipient’s tissue and bodily fluid. As noted, the implantable device 212 can be an implantable neurostimulator or a dedicated implantable tinnitus therapy device, for example. The one or more external components can be or include a charger device 205 as shown in FIG. 2A and / or an external device 210 (e.g., a mobile device, such as a smartphone or tablet) as shown in FIG. 2C.

[0032] As shown in FIG. 2A, the charger device 205 comprises an external coil 208 and an external magnet 248 fixed relative to the external coil 208. The implantable device 212 comprises an implantable coil 214 and an internal magnet 252 fixed relative to the implantable coil 214, with the implantable coil 214 being disposed outside the hermetically-sealed housing and connected to internal electrical components via a hermetic feedthrough (not shown). In general, the charger device 205 is a component that is configured to be magnetically coupled to the user’s head via the external magnet 248 and the internal magnet 252, and to be inductively coupled to the implantable device 212 via the external coil 208 and the implantable coil 214. The charger device 205 is configured to send power to the implantable device 212 (i.e., via the inductive coupling).

[0033] The charger device 205 of FIG. 2A also comprises a power source 291 (e.g., a rechargeable battery), a charging controller 293, and an RF transceiver 297. The charger device 205 of FIG. 2A is configured to charge the rechargeable power source 271 of the implantable device 212 with power (via a power signal 292) received transcutaneously from the charger device 205 by the implantable device 212. The charging controller 293 controls delivery of the power signal 292 from the power source 291 to the implantable device 212 via the RF transceiver 297 and a closely-coupled wireless link 250 (e.g., RF link) formed between the external coil 208 and the implantable coil 214 (i.e., the inductive coupling).

[0034] Referring again to the implantable device 212, the rechargeable power source 271 is a small battery (or a super-capacitor) that is configured to power the implantable device 212 after the charger device 205 is removed. In accordance with the techniques presented herein, the power circuit 275 is configured to: (1) charge the rechargeable power source 271 when the charger device 205 is present and the power signal 292 is received (refer to FIG. 2A), (2) disconnect the rechargeable power source 271 to enter a dormant state when the charger device 205 is removed and the power signal 292 is not received (refer to FIG. 2B), and (3) reconnect the rechargeable power source 271 to enter an active state when a wake-up signal 288 (e.g., a data signal, a user command, etc.) to initiate electrical stimulation is received from an external device 210 (refer to FIG. 2C). The passive telemetry circuit 277 is configured to “wake” the implantable device 212 from the dormant state and cause the power circuit 275 to reconnect the rechargeable power source 271 upon receiving a wake-up signal 288 (e.g., data signal, user command, etc.) to initiate electrical stimulation from the external device 210 (refer to FIG. 2C).

[0035] In the specific example of FIGs. 2A-2C, the implantable device 212 further comprises, or is connected with, a stimulation assembly 216 configured to be implanted in the user’s head(i.e., under the skin / tissue). The stimulation assembly 216 includes one or more stimulating electrodes 244 (one or more electrical stimulating contact(s)) for delivery of electrical stimulation (current) to the user. The stimulation assembly 216 and the one or more stimulating electrodes 244 are disposed outside the hermetically-sealed housing and connected to the stimulation control circuit 273 by a lead (one or more conductors, or wires) electrically coupling the one or more stimulating electrodes 244 to the stimulation control circuit 273 via a hermetic feedthrough (not shown) in the housing.

[0036] The stimulation control circuit 273 is configured to control electrical stimulation of a recipient (i.e., on-demand stimulation responsive to user commands, and / or as-needed stimulation responsive to sensor signals) via the one or more stimulating electrodes 244 of the stimulation assembly 216, without the need for an external component (such as a programmer or processing unit) to control the stimulation. The stimulation control circuit 273 can comprise, for example, a processing unit and / or a stimulator unit configured to generate tinnitus therapy stimulation signals based on the wake-up signal 288 (data signal, user command, etc.) received from the external device 210. In certain embodiments, the stimulation control circuit 243 can be a relatively simple pulse generator circuit. However, the tinnitus therapy techniques presented herein can be implemented with one or more processing units formed by any of, or a combination of, one or more processors (e.g., one or more Digital Signal Processors (DSPs), one or more uC cores, etc.), firmware, software, etc. arranged to perform the operations described herein. In certain embodiments, tinnitus therapy stimulation signals are provided to the stimulation assembly 216 for use in delivering electrical stimulation to the recipient (to provide relieve tinnitus symptoms experienced by the recipient) via the one or more stimulating electrodes 244. For example, the stimulation control circuit 243 can be the digital signal processor of a cochlear implant that is configured to deliver tinnitus therapy via one or more contacts of an intracochlear electrode array when not stimulating hearing (e.g., when an external sound processor is removed).

[0037] As noted, the external device 210 of FIG. 2C can be a computing device, a mobile device (e.g., the recipient’s smartphone, tablet, etc.), or a remote-control unit (e.g., a dedicated implant controller), for example, with near-field communications (NFC) capability or other similar short-range wireless communications capabilities. In the specific example of FIG. 2C, the external device 210 comprises a power source 281 (e.g., a rechargeable battery), a processor 283, a user interface 285, and a wireless transceiver 287. The processor 283 can include one or more hardware or software processors (e.g., Central Processing Units) that can obtain andexecute instructions. The processor 283 can communicate with and control the performance of other components of the external device 210. The user interface 285 can include one or more input devices for receiving input from the user and one or more output devices for providing output to the user. The one or more input devices can include physically-actuatable user-interface elements (e.g., buttons, switches, dials), a keypad, a keyboard, a mouse, a touchscreen, a voice input device, etc. that can accept user input. The one or more output devices can include a display, one or more speakers, etc. for the presentation of visual or audible information to the user. The wireless transceiver 287 can provide wireless network access and can support one or more of a variety of communication technologies and protocols, such as cellular, Bluetooth / BLE, NFC, and RF, among others. The wireless transceiver 287 can include one or more antennas and associated components configured for wireless communication according to one or more wireless communication technologies and protocols. The external device 210 and the implantable device 212 wirelessly communicate via a wireless communication link 280.

[0038] For example, the user interface 285 can be used to receive a user command to initiate stimulation, and the processor 283 can use the wireless transceiver 287 (NFC transmitter) in the external device 210 to send the wake-up signal 288 (e.g., a data signal or a user command) that is configured to “wake” the implantable device 212 via the passive telemetry circuit 277, and to start electrical stimulation of the recipient while using the rechargeable power source 271 to power the implantable device 212 and its electronic components.

[0039] As used herein, the term “passive telemetry circuit” refers to a circuit that functions to receive a wireless communications signal (e.g., a wake up command for an implantable device, such as implantable device 212), without drawing current from the implant power source (i.e., the passive telemetry circuit does not require power from an implant battery to operate), and does not actively power the implant nor charge the power source of the implant. A separate power circuit is needed for implantable devices that require external power (e.g., to recharge an implantable battery). The passive telemetry circuit can interface with a power circuit, and the two circuits can be implemented in the same hardware (e.g., the same PCB or the same ASIC), and / or share the same hardware (e.g., the same antenna), but the passive telemetry circuit does not require power from the power circuit to operate. In this regard, the passive telemetry circuit can also be considered a “non-powered” telemetry circuit. According to an aspect of the techniques described herein, when the passive telemetry circuit is activated by an external device (e.g., a mobile device, a smartphone, etc.), the passive telemetry circuitfunctions to connect the implant electronics to the implant battery, and to switch the implantable device from a dormant mode to an active mode. Conversely, the implantable device is configured to automatically switch from the active mode back into the dormant mode when a charger device is removed. In certain embodiments, near-field communications (NFC) technology can be used for the external device to trigger activation of the passive telemetry circuit.

[0040] The passive telemetry circuit described herein is distinguishable from a conventional “low-power telemetry circuit,” which refers to a circuit that is periodically powered up to check for communications (e.g., similar to the technique used with Bluetooth Low Energy (BLE) technology). In the case of a conventional low-power telemetry circuit, the implant manages the power consumed by intermittently powering the low-power telemetry circuit via the implant battery. In contrast, the passive telemetry circuit of the present disclosure is nonpowered in that it is the external device supplies power for activation of the passive telemetry circuit, permitting the implantable device to have an implant battery that is much smaller than an implant with a low-power telemetry circuit (e.g., operation on the order of hours). The passive telemetry circuit of the present disclosure has more limited capabilities. For example, in at least some embodiments the passive telemetry circuit only needs to receive a command from an external device and then connect the battery to the implant electronics. In certain embodiments, there is a separate power circuit, in addition to the passive telemetry circuit, that is dedicated for device power and / or battery charging purposes (e.g., via a 5 MHz RF link) for the implantable device, and the passive telemetry circuit is dedicated to wake-up and state switching operations. The passive telemetry circuit described herein is also distinguishable from a circuit that is configured to disconnect the battery for other purposes, such as in an emergency situation (e.g., battery faults and heating issues, etc.).

[0041] FIG. 3 is a flow diagram of an example process 300 illustrating various operations of the implant system 200 of FIG. 2A-2C to show how the implant system 200 will be used, according to the techniques presented herein.

[0042] At operation 302, a charger device 205 generates a power signal (e.g., the power signal 292 of FIG. 2A) and transmits the power signal towards an implantable device 212 of a recipient. For example, the recipient may charge the rechargeable power source 271 of the implantable device 212 in the morning (e.g., at the start of the recipient’s day, or another time throughout the course of the day) via the charger device 205. At operation 304, the implantable device 212 receives the power signal from the charger device 205 transcutaneously, chargesthe rechargeable power source 271 of the implantable device 212 via the power signal, and concurrently delivers electrical stimulation (e.g., tinnitus therapy) to the recipient (e.g., via the stimulation control circuit 273). The power circuit 275 of the implantable device 212 charges the rechargeable power source 271 when the charger device 205 is present. The implantable device 212 uses the power signal received from the charger device 205 to generate the electrical stimulation signal when the charger device 205 is present. Refer to the example of FIG. 2A (charging state) described above.

[0043] At operation 306, the charger device 205 is removed (i.e., the power signal 292 is no longer received at the implantable device 212). Detecting removal of the charger device 205 can also be referred to as detecting a “hibernation” or “dormant” trigger. When the charger device 205 is removed (at operation 306), the implantable device 212 automatically enters a dormant state (i.e., automatic hibernation, no stimulation, minimal electronics active, etc.) by disconnecting the rechargeable power source 271, at operation 308. The power circuit 275 automatically disconnects the rechargeable power source 271 when the implantable device 212 stops receiving the power signal from the charger device 205. Refer to the example of FIG. 2B (dormant state) described above. The dormant state can also be referred to as a “hibernation mode” in this example. The implantable device 212 then remains in the dormant state (e.g., no electrical stimulation is delivered while the recipient’s tinnitus is inhibited), until the recipient initiates stimulation.

[0044] At operation 310, the recipient triggers stimulation by providing user input (e.g., a command) to the external device 210 (e.g., a mobile device, such as the recipient’s smartphone) via the user interface 285. Responsive to the user input of the recipient (at operation 310), the external device 210 generates a wake-up signal (e.g., the wake-up signal 288 of FIG. 2C, such as a data signal or a user command) and transmits the wake-up signal towards the implantable device 212, at operation 312. As noted, the wireless transceiver 287 (NFC transmitter) of the external device 210 can communicate the wake-up signal 288 to the passive telemetry circuit 277 (NFC receiver) of the implantable device 212 to trigger the power circuit 15 to reconnect the rechargeable power source 271 (i.e., cause the implantable device 212 to transition from the dormant state to the active state). At operation 314, the passive telemetry circuit 277 of the implantable device 212 receives the wake-up signal from the external device 210 transcutaneously, and automatically enters an active state (i.e., electronics active, stimulation delivered, etc.). Detecting receipt of the wake-up signal from the external device 210 can also be referred to as detecting a “wake-up” trigger. Refer to the example of FIG. 2C (active state)described above. The active state can also be referred to as a “stimulation mode” in this example.

[0045] Then, at operation 316, the implantable device 212 generates and delivers electrical stimulation to the recipient, using the power stored in the rechargeable power source 271 to generate the electrical stimulation signal, in response to the passive telemetry circuit 277 receiving the wake-up signal (e.g., data signal or user command) from the external device 210.

[0046] FIG. 4 is a flowchart of example method 400 illustrating a technique for automatically causing an implantable device to enter a dormant state (hibernation mode) in which stimulation circuitry is disconnected from an internal power source of the implantable device, according to an example embodiment. Method 400 may be implemented using the implant system 200 of FIGs. 2 A and 2B, for example.

[0047] At operation 410, the method 400 includes receiving, at an implantable device, a power signal from a charger device for charging a rechargeable power source of the implantable device (charging state). At operation 420, the method 400 includes detecting removal of the charger device when the power signal is no longer received at the implantable device (hibernation trigger). At operation 430, the method 400 includes automatically disconnecting the rechargeable power source of the implantable device (enter dormant state), responsive to detecting removal of the charger device (at operation 420). At operation 440, the method 400 includes remaining in the dormant state, in which no electrical stimulation is provided to the recipient, until a wake-up trigger is detected.

[0048] FIG. 5 is a flowchart of example method 500 illustrating a technique for automatically causing an implantable device to transition from the dormant state (hibernation mode) to an active state (stimulation mode), in which the stimulation circuitry is connected from the internal power source of the implantable device, according to an example embodiment. Method 500 may be implemented using the implant system 200 of FIGs. 2B and 2C, for example.

[0049] At operation 510, the method 500 includes automatically disconnecting a rechargeable power source of an implantable device (enter dormant state), responsive to detecting removal of a charger device (when a power signal is no longer received from the charger device, this is a “hibernation” or “dormant” trigger for the implantable device). At operation 520, the method 500 includes monitoring for a “wake-up trigger” at the implantable device while in the dormant state (in which no electrical stimulation is provided to the recipient). At operation 530, the method 500 includes receiving, at the implantable device, a wake-up signal from an externaldevice based on user input to initiate stimulation. As noted above, a user command to initiate stimulation can be received at the external device and communicated to the implantable device using near-field communications (NFC) techniques. At operation 540, the method 500 includes automatically reconnecting the rechargeable power source of the implantable device (enter active state), responsive to receiving the wake-up signal from the external device. Then, the implantable device can generate and deliver electrical stimulation to the recipient while in the active state.

[0050] In some embodiments, elapsed time can be used in conjunction with, or as an alternative to, a passive telemetry circuit to trigger an implantable device to wake from a dormant state and / or initiate electrical stimulation. For example, the implantable device can automatically transition from a dormant state to an active state and / or initiate electrical stimulation when a preset time has elapsed. In some embodiments, the implantable device comprises a rewritable register (e.g., EEPROM) that a clinician or the recipient can program with a delay time for activation of the implantable device. The implantable device can be configured to initiate a low power timer and track elapsed time until the programmed activation time is reached. For example, the implantable device can track elapsed time from when the implantable device entered a dormant state (e.g., when a charger was removed), when the implantable device last delivered electrical stimulation to the recipient, or when the implantable device received a command from the recipient. The activation time can correspond to a physiological condition. For example, the implantable device can be programed with an activation time that corresponds to, or is derived from, residual inhibition of one or more symptoms (e.g., residual tinnitus inhibition, residual balance disorder inhibition, etc.), and the implantable device can be configured to initiate therapy (e.g., electrical stimulation) once the elapsed time reaches the programmed activation time.

[0051] In some embodiments, elapsed time can be used to control hibernation of the device. For example, the implantable device can automatically transition from an active state to a dormant state when a preset time has elapsed. In some embodiments, the implantable device comprises a rewritable register (e.g., EEPROM) that a clinician or the recipient can program with a delay time for hibernation of the implantable device. The implantable device can be configured to initiate a timer and track elapsed time until the programmed hibernation time is reached. For example, the implantable device can track elapsed time from when the implantable device entered an active state, when the implantable device initiated electrical stimulation of the recipient, or when the implantable device received a command from therecipient. The hibernation time can correspond to a physiological condition. For example, the implantable device can be programed with a hibernation time that corresponds to, or is derived from, a therapy that has been prescribed for the recipient (e.g., the duration of electrical stimulation needed to suppress and / or cause residual inhibition of one or more symptoms), and the implantable device can be configured to cease administration of the therapy once the elapsed time reaches the programmed hibernation time (instead of, for example, when the battery charge drops below a depletion threshold).

[0052] The implantable device charger can facilitate bidirectional communications between an external device (e.g., a smart phone, a tablet, a personal computer) and the implantable device. For example, the charger can function as a bridge that communicates with the implantable device via a near-field link (e.g., a closely coupled inductive link), and the external device via a far-field wireless link (e.g., Bluetooth). A clinician or the recipient can connect to the implantable device, using an external device that is paired with the implant charger, to configure the implantable device (e.g., set one or more programmable registers, such as an activation and / or hibernation delay time).

[0053] In another example embodiment, an implant is provided that has more than two operating states (e.g., three or four distinct power states), each with different power requirements. In at least some embodiments, the implant can transition autonomously between power states (e.g., the implant can transition sequentially through power states responsive to the output of one or more sensors). For example, a sleep apnea implant can transition from an ultra-low power state to a low state, based on the posture (e.g., gyroscope output) of the recipient, and from the low-power state to a stimulation state, based on detection of a breathing disorder (e.g., microphone output, or accelerometer output) of the recipient. Similarly, a vestibular implant can transition from an ultra low-power state based on the posture (e.g., gyroscope output) of the recipient, and from the low-power state to a stimulation state based on detection of unstable gait and / or balance disorder (e.g., accelerometer output). In other embodiments, one or more transitions can be initiated by a recipient / triggered responsive to recipient input. For example, an implantable device can be configured to transition from a first state to a second state (e.g., transition from a dormant state to a low power state) responsive to receipt of a wireless signal at a passive telemetry circuit, and transition from the second state to a third state (e.g., transition from the low power state to a stimulating state) responsive to a condition detected by the implantable device (e.g., recipient posture or movement). The power consumed by the implant and / or the implant components that are powered / active in each powerstate can be controlled dependent on the functionality required of the implant. For example, the implant electronics can be configured to operate in several different power states to optimize the implants power consumption.

[0054] An example “two-stage wake-up procedure” for an implantable device is described below with reference to FIGs. 6A, 6B, and 6C, which are diagrams of an implant system 600 including an implantable device 612 according to another example embodiment of the techniques presented herein.

[0055] FIG. 6A is diagram illustrating an example of an implant system 600 automatically entering a first power state (i.e., an ultra low-power state) from a charging state based on a hibernation trigger. For example, the implantable device 612 automatically enters the first power state based on removal of the charger device 605 (i.e., failure to receive the power signal 692 at the implantable device 612). In the example of FIG. 6A, first circuitry 672 is powered / active in the first power state (hibernation mode). In certain embodiments, the first circuitry 672 includes a first sensor N1 (e.g., a low-power gyroscope or accelerometer) that is powered / active while the implantable device 612 is in the first power state. In some other embodiments, the first circuitry 672 can additionally or alternatively include a passive telemetry circuit 677. The first circuitry 672 can also comprise a power circuit (or a portion thereof) for controlling one or more switches connected to the rechargeable power source 671. However, various other components of the implantable device 612 are depowered / inactive while the implantable device 612 is in the first power state (e.g., second circuitry 674, third circuitry 676, etc. are deactivated / disabled). As shown in FIG. 6A, both a first switch SI and a second switch S2 are open in the first power state (hibernation mode).

[0056] FIG. 6B is a diagram illustrating an example of the implant system 600 automatically transitioning from the first power state to a second power state (i.e., an intermediate low-power monitoring state between the first power state and the third power state). The implant system 600 has a greater power budget and more active electronics in the second power state (compared to the first power state) in the illustrated embodiment. The transition from the first power state to the second power state is based on a first wake-up trigger (stage 1 of the two- stage wake-up procedure). For example, the first wake-up trigger can correspond to a first output signal of the first sensor N 1 (or alternatively, a first wake-up signal 686 received by the passive telemetry circuit 677 via a wireless communication link 680) of the first circuitry 672. In the example of FIG. 6B, second circuitry 674 is powered / active in the second power state (monitoring state / low-power mode). In certain embodiments, the second circuitry 674includes a second sensor N2 (e.g., a microphone, a breathing sensor such as an accelerometer that detects movements of the recipient’s diaphragm, etc.) that is depowered / active while the implantable device 612 is in the second power state. In some other embodiments, the second circuitry 674 can include an active telemetry circuit 679 (e.g., Bluetooth / BLE receiver, etc.), which can be powered / active in the second power state. The second sensor N2 and / or the active telemetry circuit 679 of the second circuitry 674 can be low-power components, but in some instances can be relatively higher power components in comparison to the first sensor N 1 of the first circuitry 672. The second circuitry 674 can also comprise a power circuit (or a portion thereof) for controlling one or more of the switches connected to the rechargeable power source 671. However, some other components of the implantable device 612 are still depowered / inactive while the implantable device 612 is in the second power state (e.g., the third circuitry 676 remains depowered / inactive). As shown in FIG. 6B, the first switch SI is now closed such that the second circuitry 674 is now powered / activate, and the second switch S2 is still open such that third circuitry 676 remains depowered / inactive, in the second power state (monitoring state / low-power mode).

[0057] FIG. 6C is a diagram illustrating an example of the implant system 600 automatically transitioning from the second power state to a third power state (i.e., a full active state for stimulation). The implant system 600 has a greater power budget and more active electronics in the third power state (compared to the second power state) in the illustrated embodiment. The transition from the second power state to the third power state is based on a second wakeup trigger (stage 2 of the two-stage wake-up procedure). For example, the second wake-up trigger can correspond to a second output signal of the second sensor N2 (or alternatively, a second wake-up signal 688 received by the active telemetry circuit 679 via the wireless communication link 680) of the second circuitry 674. In some embodiments, the second wakeup trigger is based on more than one condition (output / signal) being satisfied. For example, the second wake-up signal can require both the first output signal of the first sensor N 1 and the second output signal of the second sensor N2 (e.g., the output from both sensors concurrently satisfying trigger conditions), or the second wake-up signal 688 in combination with the second output signal of the second sensor N2. In the example of FIG. 6C, third circuitry 676 is powered on / active in the third power state (active state / stimulation mode). In certain embodiments, the third circuitry 676 can comprise various stimulation components (not shown in FIGs. 6A-6C), such as a processing unit, stimulation control circuit, a stimulator unit, a pulse generator circuit, a stimulation assembly, one or more stimulating electrode(s), etc.), which arepowered / active while the implantable device 612 is in the third power state and deliver electrical stimulation to the recipient (e.g., for suppression of tinnitus, etc.). As shown in FIG. 6C, the second switch S2 is now closed such that the third circuitry 676 is now powered / active in the third power state (active state / stimulation mode).

[0058] FIG. 7 is a flowchart of example method 700 illustrating a two-stage wake-up procedure for an implantable device, according to an example embodiment. Method 700 may be implemented using the implant system 600 of FIGs. 6A-6C, for example.

[0059] At operation 710, the method 700 includes receiving, at an implantable device, a power signal from a charger device for charging a rechargeable power source of the implantable device. This is a charging state (or charging mode) during which the power signal received from the charger device can be used to charge the rechargeable power source, as well as to power the implantable device to generate and deliver electrical stimulation to the recipient.

[0060] At operation 720, the method 700 includes automatically entering a first power state (a first power state) based on a failure to receive the power signal from the charger device at the implantable device. The implantable device can enter the first power state by electrically disconnecting the rechargeable power source of the implantable device (i.e., entering a dormant state) or by depowering / inactivating select circuity (e.g., the second circuitry 674 and third circuitry 676 of the implant system of FIGs. 6A-6C) to reduce the power budget of the implantable device when the charger device is removed (hibernation trigger), for example. In this example, the implantable device will remain in the first power state until one or more particular output signals are obtained via one or more sensors of the implantable device. In this example, the term “first circuitry” corresponds to a first sensor (e.g., a gyroscope or accelerometer) that will remain active in the first power state, and possibly one or more other components (e.g., a first passive telemetry circuit). Preferably, the first sensor that remains active while in the first power state is a relatively low-power sensor that can be used to transition from the first power state to another power state, without substantially draining power from the implant battery. Thus, the first power state can also be referred to as an ultra low-power state or hibernation mode, for example.

[0061] At operation 730, the method 700 includes transitioning from the first power state to a second power state (a low-power monitoring state) based on a first output signal from the first sensor (e.g., detect posture of the recipient based on output from a gyroscope or an accelerometer). The first sensor output signal corresponds to a “first wake-up trigger” in thisexample embodiment. The implantable device enters the second power state (monitoring state) by electrically reconnecting the rechargeable power source of the implantable device, or by activating monitoring circuitry of the implantable device, but operating in a low-power monitoring mode (e.g., limited components such as one or more sensor(s) are active, but the stimulator unit remains inactive). In this example, the term “monitoring circuitry” corresponds to a second sensor (e.g., a microphone or other breathing sensor, such as an accelerometer that detects movement of the recipient’s diaphragm) that will remain active in the second power state (monitoring state), and possibly one or more other components (e.g., an active telemetry circuit). Operation 730 corresponds to the first stage of the two-stage wake-up procedure. In certain embodiments, at least the second sensor of the one or more sensors will be activated in the second power state (monitoring state), and the second sensor can be used, either solely or in combination with the active telemetry circuit and / or the first sensor, to further transition from the low-power monitoring state to another power state.

[0062] At operation 740, the method 700 includes automatically entering a third power state (an active state) based on a second output signal from the second sensor (e.g., detect a breathing disorder based on output from a microphone or other breathing sensor, detecting a balance disorder based on a balance sensor, etc.). The second sensor output signal corresponds to a “second wake-up trigger” in this example embodiment. In other embodiments, the second sensor signal in combination with one or more other signals (e.g., other sensor signals, telemetry signal, etc.) can correspond to the “second wake-up trigger”. The implantable device enters the third power state (active state) by electrically reconnecting the rechargeable power source of the implantable device to the stimulation circuitry of the implantable device, and operating in a stimulation mode (e.g., most or all components active, including the stimulator unit). In this example, the term “stimulation circuitry” corresponds to one or more stimulation components (e.g., a control circuit, a stimulator unit, a stimulation assembly, one or more stimulating electrode(s), etc.) that will be activated in the third power state (active state). Thus, the active state can also be referred to as a stimulation mode, for example. Operation 740 corresponds to the second stage of the two-stage wake-up procedure.

[0063] In some example embodiments, the second sensor that provides the second output signal (e.g., a microphone or other breathing sensor that detects a breathing disorder) can be a different sensor than the first sensor that provides the first output signal (i.e., a gyroscope or an accelerometer that detects the recipient’s posture), such that different sensors and corresponding sensor outputs can be used to transition between different power states of theimplantable device. In some other embodiments, however, the second sensor that provides the second output signal can be the same sensor as the first sensor that provides the first output signal, such that different sensor outputs from a single sensor can be used to transition between the different power states of the implantable device. For example, the sensor can comprise an inertial measurement unit (i.e., a combined gyroscope and accelerometer) that outputs a first signal indicative of the recipient’s posture (e.g., standing or lying down) that causes transition from the first power state to the second power state, and a second signal indicative of the recipient’s diaphragm movement (e.g., repetitious motion that can be analyzed by a processor to detect disordered breathing) that causes transition from the second power state to the third power state. In yet some other embodiments, combinations of two or more outputs from two or more sensors can be used to transition between the different power states, respectively.

[0064] In certain embodiments, the implantable device can also transition back to a previous lower power state from a higher power state. For example, the implantable device can transition from a stimulating state to a monitoring state, and / or from the monitoring state to a hibernating or dormant state (e.g., revert back to the monitoring state or to the hibernating state based on one or more additional sensor outputs from one or more of the sensors, based on a timer, based on an additional user command, etc.) in the method 700 of FIG. 7. Likewise, the implantable device can also transition to the charging state from any of the other power states when the charger device is present and the power signal is received at the implantable device for recharging the rechargeable power source in the method 700 of FIG. 7 (e.g., the implantable device can transition from a dormant or hibernating state to a simulating and / or charging state in the presence of a charging signal / charging power received at a charging / power circuit).

[0065] Thus, the implantable device 612 described above with reference to FIGs. 6A-6C can utilize the techniques of the method 700 described above with reference to FIG. 7 to implement a multi-stage implant wake-up procedure that involves operating using different power states at different times or in different scenarios, and that can utilize various different sensors / sensor outputs as triggers to progressively transition between the different power states, respectively, in an iterative manner over time. The above-described examples are by way of illustration and not limitation, and the various techniques described herein can be applied similarly in various other implementations.

[0066] As described elsewhere herein, it is to be appreciated that use of electrical stimulation signals for providing tinnitus therapy to an implant recipient is merely illustrative of one technique that can be used in accordance with embodiments presented herein. In particular, inalternative arrangements, the tinnitus therapy signals can be mechanical stimulation signals (e.g., delivered at the same location or a different location), electro-mechanical stimulation signals (e.g., electrical signals and mechanical signals delivered simultaneously or in close temporal proximity to one another), acoustic stimulation signals, electro-acoustic stimulation signals (e.g., electrical signals and acoustic signals delivered simultaneously or in close temporal proximity to one another), etc.

[0067] Certain aspects of the techniques presented herein can be implemented by an implantable device comprising a first wireless circuit and a second wireless circuit. The first wireless circuit is configured to receive first wireless signals transmitted through the skin of a recipient in a first frequency band from a first external device, while the second wireless circuit is configured to receive second wireless signals transmitted through the skin of the recipient in a second frequency band from a second external device. In certain examples, the first frequency is a frequency that is less than about 60 MHz. In further embodiments, the first frequency is a frequency of approximately 13.56 MHz in the globally available unlicensed radio frequency ISM band. In certain embodiments, the second frequency is a frequency of 5 MHz. In other embodiments, the second frequency is a frequency of 6.78 MHz (e.g., in a range of 6.765 MHz - 6.975 MHz). The implantable device is configured to automatically transition from a first state to a second state responsive to the first wireless circuit receiving the first wireless signals, and to automatically transition from the first state to a third state responsive to the second wireless circuit receiving the second wireless signals.

[0068] As previously described, the technology disclosed herein can be applied in any of a variety of circumstances and with a variety of different devices. The techniques of the present disclosure can be applied to various other devices, such as neurostimulators, sleep apnea management stimulators, seizure therapy stimulators, tinnitus management stimulators, and vestibular stimulation devices, as well as other medical devices that deliver stimulation to tissue or capture physiological measurements from tissue. One example device that can benefit from technology disclosed herein is described in more detail below with reference to FIG. 8.

[0069] FIG. 8 illustrates an example vestibular stimulator system 802, with which embodiments presented herein can be implemented. As shown, the vestibular stimulator system 802 comprises an implantable component referred to as a vestibular stimulator 812, as well as an external device 804 (e.g., external processing device, external component, battery charger, remote control, etc.). The external device 804 comprises a transceiver unit 860. Assuch, the external device 804 is configured to transfer data (and potentially power) to the vestibular stimulator 812.

[0070] The vestibular stimulator 812 comprises an implant body 834 (main module), a lead region 836, and a stimulating assembly 816, all configured to be implanted under the skin / tissue 815 of the recipient. The implant body 834 generally comprises a hermetically-sealed housing 838 in which RF interface circuitry, one or more rechargeable batteries, one or more processors, and a stimulator unit are disposed. The implant body 834 also includes an intemal / implantable coil 814 that is generally external to the hermetically-sealed housing 838, but which is connected to the transceiver via a hermetic feedthrough (not shown).

[0071] The stimulating assembly 816 comprises a plurality of electrodes 844(l)-(3) disposed in a carrier member (e.g., a flexible silicone body). In this specific example, the stimulating assembly 816 comprises three (3) stimulation electrodes, referred to as stimulation electrodes 844(1), 844(2), and 844(3). The stimulation electrodes 844(1), 844(2), and 844(3) function as an electrical interface for delivery of electrical stimulation signals to the recipient’s vestibular system.

[0072] The stimulating assembly 816 is configured such that a surgeon can implant the stimulating assembly adjacent the recipient’s otolith organs via, for example, the recipient’s oval window. It is to be appreciated that this specific embodiment with three stimulation electrodes is merely illustrative and that the techniques presented herein may be used with stimulating assemblies having different numbers of stimulation electrodes, stimulating assemblies having different lengths, etc. In operation, the vestibular stimulator 812, the external device 804, and / or another external device can be configured to implement the techniques presented herein.

[0073] As should be appreciated, while particular uses of the technology have been illustrated and discussed above, the disclosed technology can be used with a variety of devices in accordance with many examples of the technology. The above discussion is not meant to suggest that the disclosed technology is only suitable for implementation within systems akin to that illustrated in the figures. In general, additional configurations can be used to practice the processes and systems herein and / or some aspects described can be excluded without departing from the processes and systems disclosed herein.

[0074] This disclosure described some aspects of the present technology with reference to the accompanying drawings, in which only some of the possible aspects were shown. Otheraspects can, however, be embodied in many different forms and should not be construed as limited to the aspects set forth herein. Rather, these aspects were provided so that this disclosure was thorough and complete and fully conveyed the scope of the possible aspects to those skilled in the art.

[0075] As should be appreciated, the various aspects (e.g., portions, components, etc.) described with respect to the figures herein are not intended to limit the systems and processes to the particular aspects described. Accordingly, additional configurations can be used to practice the methods and systems herein and / or some aspects described can be excluded without departing from the methods and systems disclosed herein.

[0076] According to certain aspects, systems and non-transitory computer readable storage media are provided. The systems are configured with hardware configured to execute operations analogous to the methods of the present disclosure. The one or more non-transitory computer readable storage media comprise instructions that, when executed by one or more processors, cause the one or more processors to execute operations analogous to the methods of the present disclosure.

[0077] Similarly, where steps of a process are disclosed, those steps are described for purposes of illustrating the present methods and systems and are not intended to limit the disclosure to a particular sequence of steps. For example, the steps can be performed in differing order, two or more steps can be performed concurrently, additional steps can be performed, and disclosed steps can be excluded without departing from the present disclosure. Further, the disclosed processes can be repeated.

[0078] Although specific aspects were described herein, the scope of the technology is not limited to those specific aspects. One skilled in the art will recognize other aspects or improvements that are within the scope of the present technology. Therefore, the specific structure, acts, or media are disclosed only as illustrative aspects. The scope of the technology is defined by the following claims and any equivalents therein.

[0079] It is also to be appreciated that the embodiments presented herein are not mutually exclusive and that the various embodiments may be combined with another in any of a number of different manners.

Claims

CLAIMSWhat is claimed is:

1. A system, comprising: an implantable neurostimulator with a rechargeable power source; and an external charger configured to charge the rechargeable power source, wherein the implantable neurostimulator is configured to enter a dormant state when the external charger is removed after charging the rechargeable power source, and to remain in the dormant state until receipt of a user command.

2. The system of claim 1, wherein the rechargeable power source comprises an implantable battery.

3. The system of claim 1, wherein the rechargeable power source comprises a super capacitor.

4. The system of claim 1 or 2, wherein the implantable neurostimulator comprises a power circuit, wherein the power circuit is configured to supply the implantable neurostimulator with power for electrical stimulation and charge the rechargeable power source with power received transcutaneously from the external charger while the external charger is present, and to disconnect the rechargeable power source to automatically enter the dormant state when the external charger is removed.

5. The system of claim 4, wherein no electrical stimulation is delivered to a recipient of the implantable neurostimulator while in the dormant state.

6. The system of claim 4, wherein the implantable neurostimulator comprises a passive telemetry circuit configured to receive the user command and wake the implantable neurostimulator from the dormant state responsive to receipt of the user command.

7. The system of claim 4, wherein the power circuit is further configured to reconnect the rechargeable power source to automatically enter an active state responsive to receipt of the user command.

8. The system of claim 7, wherein the implantable neurostimulator further comprises a control circuit configured to control electrical stimulation delivered to a recipient of the implantable neurostimulator while in the active state responsive to receipt of the user command.

9. The system of claim 1 or 2, further comprising: an external device configured to transmit the user command to the implantable neurostimulator using short-range wireless communications.

10. An implantable device, comprising: a rechargeable power source and an electronic assembly housed within a hermetic enclosure, wherein the electronic assembly is configured to charge the rechargeable power source with power received transcutaneously from a charger device; and a stimulating electrode connected to the electronic assembly via a feedthrough in the hermetic enclosure, wherein the stimulating electrode is configured to deliver electrical stimulation to a recipient of the implantable device, wherein the implantable device is configured to concurrently charge the rechargeable power source and deliver electrical stimulation to the recipient with power received transcutaneously from the charger device, and to automatically stop delivering electrical stimulation to the recipient when the implantable device ceases to receive power from the charger device.

11. The implantable device of claim 10, wherein the electronic assembly comprises a passive telemetry circuit configured to initiate delivery of electrical stimulation to the recipient, in absence of the charger device, responsive to receipt of a transcutaneous communications signal from an external device.

12. The implantable device of claim 11, wherein the electronic assembly is configured to electrically disconnect the rechargeable power source when the implantable device ceases to receive power from the charger device, and to electrically reconnect the rechargeable power source when the passive telemetry circuit receives the transcutaneous communications signal from the external device.

13. The implantable device of claim 12, wherein the electronic assembly comprises a power circuit configured to charge the rechargeable power source with the power received transcutaneously from the charger device while the charger device is present, to electrically disconnect the rechargeable power source and automatically stop delivering electrical stimulation to the recipient when the implantable device ceases to receive power from the charger device, and to electrically reconnect the rechargeable power source and automatically deliver electrical stimulation to the recipient using power from the rechargeable power source responsive to the passive telemetry circuit receiving the transcutaneous communications signal from the external device.

14. The implantable device of claim 13, wherein the electronic assembly comprises a control circuit configured to control the electrical stimulation delivered to the recipient responsive to the passive telemetry circuit receiving the transcutaneous communications signal from the external device.

15. An implantable neurostimulator, comprising: a rechargeable power source; an electronic assembly configured to charge the rechargeable power source with power received transcutaneously from a charger device; and a passive telemetry circuit, wherein the implantable neurostimulator is configured to connect the rechargeable power source to the electronic assembly responsive to the passive telemetry circuit receiving a signal from an external device.

16. The implantable neurostimulator of claim 15, wherein the implantable neurostimulator further comprises: a power circuit configured to electrically disconnect the rechargeable power source, irrespective of the power stored in the rechargeable power source, when the implantable neurostimulator is not delivering electrical stimulation to a recipient.

17. The implantable neurostimulator of claim 15 or 16, wherein the power circuit is configured to electrically disconnect the rechargeable power source from the electronic assembly when the electronic assembly ceases to receive power from the charger device, andto electrically reconnect the rechargeable power source to the electronic assembly responsive to the passive telemetry circuit receiving the signal from the external device.

18. The implantable neurostimulator of claim 17, wherein the signal received from the external device comprises a user command of the recipient, and wherein the implantable neurostimulator is configured to initiate electrical stimulation of the recipient, using power stored in the rechargeable power source to create the electrical stimulation, responsive to the passive telemetry circuit receiving the user command from the external device.

19. An implantable neurostimulator comprising: a rechargeable power source; and a passive telemetry circuit, wherein the implantable neurostimulator is configured to initiate electrical stimulation of a recipient of the implantable neurostimulator, using power stored in the rechargeable power source to create the electrical stimulation, responsive to the passive telemetry circuit receiving a signal from an external device.

20. The implantable neurostimulator of claim 19, further comprising: a power circuit configured to electrically disconnect the rechargeable power source, irrespective of the power stored in the rechargeable power source, when the implantable neurostimulator is not delivering electrical stimulation to the recipient.

21. The implantable neurostimulator of claim 19 or 20, further comprising: an electronic assembly configured to charge the rechargeable power source with power received transcutaneously from a charger device; and a power circuit configured to electrically disconnect the rechargeable power source from the electronic assembly when the electronic assembly ceases to receive power from the charger device, and to electrically reconnect the rechargeable power source to the electronic assembly responsive to the passive telemetry circuit receiving the signal from the external device, wherein the signal received from the external device comprises a user command to initiate the electrical stimulation of the recipient.

22. A method comprising:receiving, at an implantable device, a power signal from a charger device for charging a rechargeable power source of the implantable device in a charging state; and automatically entering a first power state, by disconnecting the rechargeable power source from stimulation circuitry and monitoring circuitry of the implantable device, based on failure to receive the power signal from the charger device, wherein the first power state is a dormant state.

23. The method of claim 22, further comprising: receiving a first output signal from a first sensor of dormant circuitry of the implantable device; and transitioning from the first power state to a second power state, by reconnecting the rechargeable power source to the monitoring circuitry, based on the first output signal of the first sensor, wherein the second power state is a low-power monitoring state.

24. The method of claim 23, further comprising: receiving a second output signal from a second sensor of the monitoring circuitry of the implantable device; and automatically entering a third power state, by reconnecting the rechargeable power source to the stimulation circuitry, based on the second output signal of the second sensor, wherein the third power state is an active state for delivering stimulation to a recipient of the implantable device.

25. The method of claim 22, 23, or 24, further comprising: receiving a first wake-up signal from an external device at a first telemetry circuit of dormant circuitry of the implantable device, wherein the first telemetry circuit is a passive telemetry circuit; and transitioning from the first power state to a second power state, by reconnecting the rechargeable power source to the monitoring circuitry, based on receipt of the first wake-up signal from the external device at the first telemetry circuit, wherein the second power state is a low-power monitoring state.

26. The method of claim 25, further comprising:receiving a second wake-up signal from the external device at a second telemetry circuit of the monitoring circuitry of the implantable device, wherein the second telemetry circuit is an active telemetry circuit; and automatically entering a third power state, by reconnecting the rechargeable power source to the stimulation circuitry, based on receipt of the second wake-up signal from the external device at the second telemetry circuit, wherein the third power state is an active state for delivering stimulation to a recipient of the implantable device.

27. An implantable device comprising: a first wireless circuit, wherein the first wireless circuit is configured to receive first wireless signals transmitted through the skin of a recipient in a first frequency band from a first external device; and a second wireless circuit, wherein the second wireless circuit is configured to receive second wireless signals transmitted through the skin of the recipient in a second frequency band from a second external device; wherein the implantable device is configured to automatically transition from a first state to a second state responsive to the first wireless circuit receiving the first wireless signals, and to automatically transition from the first state to a third state responsive to the second wireless circuit receiving the second wireless signals.

28. The implantable device of claim 27, wherein the implantable device is configured to automatically transition from the second state to the first state responsive to the first wireless circuit ceasing to receive the first wireless signals.

29. The implantable device of claim 28, wherein the implantable device is configured to remain in the third state responsive to the second wireless circuit ceasing to receive the second wireless signals.

30. The implantable device of claim 27, 28, or 29, wherein the implantable device is configured to operate in the second state responsive to the second wireless circuit receiving the second wireless signals concurrently with the first wireless circuit receiving the first wireless signals.

31. The implantable device of claim 27, 28, or 29, wherein the implantable device comprises a rechargeable battery, and the implantable device is configured to charge the battery in the first state, and to discharge the battery in the second state.

32. The implantable device of claim 27, 28, or 29, wherein the implantable device is configured to deliver electrical stimulation to the recipient in the first state and the second state.

33. The implantable device of claim 27, 28, or 29, wherein the first wireless circuit comprises a wireless transceiver and a first antenna, and the second wireless circuit comprises a wireless receiver and a second antenna.

34. The implantable device of claim 27, 28, or 29, wherein the first wireless circuit comprises a resonant inductive power transfer circuit comprising a coil antenna and a resonant tank that are tuned to operate at a frequency less than about 60MHz.

35. The implantable device of claim 27, 28, or 29, wherein the second wireless circuit is a passive telemetry circuit that is configured to latch the implantable device in the third state responsible to receipt of a transitory wireless trigger.

36. One or more non-transitory computer readable storage media of an implantable device comprising a rechargeable power source, wherein the one or more non-transitory computer readable storage media comprise instructions that, when executed by one or more processors, are configured to: cause the implantable neurostimulator is configured to enter a dormant state when an external charger is removed after charging the rechargeable power source, and to remain in the dormant state until receipt of a user command.

37. The non-transitory computer readable storage media of claim 36, wherein the one or more non-transitory computer readable storage media are configured use a power circuit to supply the implantable device with power for electrical stimulation and to charge the rechargeable power source with power received transcutaneously from the external charger while the external charger is present, and to disconnect the rechargeable power source to automatically enter the dormant state when the external charger is removed.

38. The non-transitory computer readable storage media of claim 36 or 37, wherein no electrical stimulation is delivered to a recipient of the implantable device while in the dormant state.

39. The non-transitory computer readable storage media of claim 36 or 37, wherein the one or more non-transitory computer readable storage media are configured to reconnect the rechargeable power source to automatically enter an active state responsive to receipt of the user command.

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