Abstract: Devices, systems, and techniques for controlling charging power transmitted to an implantable medical device during a recharging process based on patient activity are disclosed. Various example techniques include a method comprising receiving, by processing circuitry, an activity signal generated by an implantable medical device and indicative of an activity level of a patient during charging of a rechargeable power source of the implantable medical device implanted in the patient, determining, by the processing circuitry and based on the activity signal, a patient status for the patient during charging of the rechargeable power source, and controlling, by the processing circuitry and based on the patient status, charging of the rechargeable power source of the implantable medical device.

Abstract: In some examples, a medical device system includes a first implantable medical device. The first implantable medical device (IMD) may comprise circuitry configured to at least one of deliver a therapy to a patient or sense a physiological signal from the patient; generate stimulation deliverable to a patient; a first rechargeable power source; and a secondary coil coupled to the first rechargeable power source, the secondary coil configured to charge the first rechargeable power source via inductive coupling with a primary coil of an external charging device. The medical device system may comprise processing circuitry configured to control charging of the first rechargeable power source based on a charge state of a second rechargeable power source of a second IMD.

Abstract: Devices, systems, and techniques for monitoring the temperature of a device used to charge a rechargeable power source are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. The temperature of an external charging device and/or an implantable medical device may be monitored to control the temperature exposure to patient tissue. In one example, a temperature sensor may sense a temperature of a portion of a device, wherein the portion is non-thermally coupled to the temperature sensor. A processor may then control charging of the rechargeable power source based on the sensed temperature.

Abstract: In some examples, a medical device system includes a first implantable medical device. The first implantable medical device (IMD) may comprise circuitry configured to at least one of deliver a therapy to a patient or sense a physiological signal from the patient; generate stimulation deliverable to a patient; a first rechargeable power source; and a secondary coil coupled to the first rechargeable power source, the secondary coil configured to charge the first rechargeable power source via inductive coupling with a primary coil of an external charging device. The medical device system may comprise processing circuitry configured to control charging of the first rechargeable power source based on a charge state of a second rechargeable power source of a second IMD.

Abstract: Devices, systems, and techniques for controlling charging power based on a cumulative thermal dose to a patient are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. An external charging device may calculate an estimated cumulative thermal dose delivered to the patient during charging over a predetermined period of time. Based on the estimated cumulative thermal dose, the external charging device may select a power level for subsequent charging of the rechargeable power source. In one example, the charging device may select a high power level when the cumulative thermal dose has not exceeded a thermal dose threshold and select a low power level when the cumulative thermal dose has exceeded the thermal dose threshold.

Abstract: Devices, systems, and techniques for controlling charging power based on a cumulative thermal dose to a patient are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. An external charging device may calculate an estimated cumulative thermal dose delivered to the patient during charging over a predetermined period of time. Based on the estimated cumulative thermal dose, the external charging device may select a power level for subsequent charging of the rechargeable power source. In one example, the charging device may select a high power level when the cumulative thermal dose has not exceeded a thermal dose threshold and select a low power level when the cumulative thermal dose has exceeded the thermal dose threshold.

Abstract: Devices, systems, and techniques for monitoring the temperature of a device used to charge a rechargeable power source are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. The temperature of an external charging device and/or an implantable medical device may be monitored to control the temperature exposure to patient tissue during a charging session used to recharge the rechargeable power source. In one example, a temperature sensor may sense a temperature of an internal portion of a device, wherein the housing of the device is not directly thermally coupled to the temperature sensor. A temperature for the housing of the device may then be estimated based on the sensed temperature provided by the non-thermally coupled temperature sensor. A processor may then control charging of the rechargeable power source based on the determined temperature for the housing.

Abstract: Devices, systems, and techniques for monitoring the temperature of a device used to charge a rechargeable power source are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. The temperature of an external charging device and/or an implantable medical device may be monitored to control the temperature exposure to patient tissue during a charging session used to recharge the rechargeable power source. In one example, a temperature sensor may sense a temperature of an internal portion of a device, wherein the housing of the device is not directly thermally coupled to the temperature sensor. A temperature for the housing of the device may then be estimated based on the sensed temperature provided by the non-thermally coupled temperature sensor. A processor may then control charging of the rechargeable power source based on the determined temperature for the housing.

Abstract: In some examples, a medical device system includes a first implantable medical device. The first implantable medical device (IMD) may comprise circuitry configured to at least one of deliver a therapy to a patient or sense a physiological signal from the patient; generate stimulation deliverable to a patient; a first rechargeable power source; and a secondary coil coupled to the first rechargeable power source, the secondary coil configured to charge the first rechargeable power source via inductive coupling with a primary coil of an external charging device. The medical device system may comprise processing circuitry configured to control charging of the first rechargeable power source based on a charge state of a second rechargeable power source of a second IMD.

Abstract: In some examples, an implantable medical device (IMD) including a hermetically sealed housing that is configured to enclose internal components. The internal components may include stimulation circuitry, processing circuitry configured to control the stimulation circuitry to deliver electrical stimulation using one or more leads received by the housing, telemetry circuitry, and a rechargeable power source. The IMD may also include a coil configured to at least one of receive energy to recharge the rechargeable power source or receive and/or transmit signals for wireless telemetry with another device, wherein the implantable medical device is configured to mount to a cranium of a patient, and wherein the coil is coiled about an axis that is approximately orthogonal to a major surface of the IMD.

Abstract: Devices, systems, and techniques for monitoring the temperature of a device used to charge a rechargeable power source are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. The temperature of an external charging device and/or an implantable medical device may be monitored to control the temperature exposure to patient tissue during a charging session used to recharge the rechargeable power source. In one example, a temperature sensor may sense a temperature of an internal portion of a device, wherein the housing of the device is not directly thermally coupled to the temperature sensor. A temperature for the housing of the device may then be estimated based on the sensed temperature provided by the non-thermally coupled temperature sensor. A processor may then control charging of the rechargeable power source based on the determined temperature for the housing.

Abstract: Devices, systems, and techniques for managing heat generated in coils for wireless energy transmission are disclosed. Inductive coupling between two coils may be used to recharge the power source of an implantable medical device. A phase change material may be thermally coupled to a flexible coil to absorb heat generated during the inductive coupling and reduce temperature increases of the flexible coil. The flexible coil may be configured to at least one of transmit energy to or receive energy from a second coil, and the phase change material may be configured to deform with the flexible coil and absorb heat from the flexible coil. The phase change material may be contained within thermally conductive tubes or channels configured in shapes that promote flexibility of the flexible coil.

Abstract: Reservoir volume of implantable infusion devices may be determined using a volume sensor that provides a signal representative of a distance between the volume sensor and a movable wall of the reservoir. The volume sensor may be a light-based or sound-based sensor, and may be located outside of the reservoir.

Abstract: Devices, systems, and techniques for estimating energy transfer to tissue of a patient during battery charging for an implantable medical device are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. An external charging device may calculate an estimated energy transfer to tissue of the patient that may include a resistive heat loss from the rechargeable power source and/or electromagnetic energy transfer directly to tissue. Based on the estimated energy transfer, the external charging device may select a power level for charging of the rechargeable power source. In one example, the charging device may select a high power level when the estimated energy transfer has not exceeded an energy transfer threshold and select a low power level when the estimated energy transfer has exceeded the energy transfer threshold.

Abstract: An implantable medical device (IMD) includes a housing that is configured to enclose internal components including at least a processor and a power source. The housing defines two major surfaces that are generally parallel to each other and one or more channels that are each configured to receive a lead and electrically couple the respective lead to the internal components, where each of the channels extend substantially straight in to the housing along an axis generally parallel to the two major surfaces. The housing may be configured to be mounted to a cranium of a patient such that at least one of the two major surfaces approximates a curvature of the cranium. The IMD may include one or more funneling walls that define a rounded and smooth transition from a sidewall of the housing to a surface that defines one or more mouths to the channels.

Abstract: Devices, systems, and techniques for controlling charging power transmitted to an implantable medical device during a recharging process based on patient activity are disclosed. Various example techniques include a method comprising receiving, by processing circuitry, an activity signal generated by an implantable medical device and indicative of an activity level of a patient during charging of a rechargeable power source of the implantable medical device implanted in the patient, determining, by the processing circuitry and based on the activity signal, a patient status for the patient during charging of the rechargeable power source, and controlling, by the processing circuitry and based on the patient status, charging of the rechargeable power source of the implantable medical device.

Abstract: Devices, systems, and techniques are described for use in recharging a power source of a cranially mounted implantable medical device. In one example, a wearable medical device includes a flexible body configured to cover at least a portion of a scalp of a head of a patient. A securing member is connected to the flexible body and configured to extend around a circumference of the head to stabilize the flexible body with respect to the scalp of the patient. A fixation member is configured to mount to a location of the flexible body and couple the flexible body to a recharge coil that is configured to recharge the power source of the cranially-mountable implantable medical device.

Abstract: Reservoir volume of implantable infusion devices may be determined using a volume sensor that provides a signal representative of a distance between the volume sensor and a movable wall of the reservoir. The volume sensor may be a light-based or sound-based sensor, and may be located outside of the reservoir.

Abstract: Devices, systems, and techniques for monitoring the temperature of a device used to charge a rechargeable power source are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. The temperature of an external charging device and/or an implantable medical device may be monitored to control the temperature exposure to patient tissue. In one example, a temperature sensor may sense a temperature of a portion of a device, wherein the portion is non-thermally coupled to the temperature sensor. A processor may then control charging of the rechargeable power source based on the sensed temperature.

Abstract: Devices, systems, and techniques for estimating energy transfer to tissue of a patient during battery charging for an implantable medical device are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. An external charging device may calculate an estimated energy transfer to tissue of the patient that may include a resistive heat loss from the rechargeable power source and/or electromagnetic energy transfer directly to tissue. Based on the estimated energy transfer, the external charging device may select a power level for charging of the rechargeable power source. In one example, the charging device may select a high power level when the estimated energy transfer has not exceeded an energy transfer threshold and select a low power level when the estimated energy transfer has exceeded the energy transfer threshold.