Abstract: A current management system for use in the stimulation output stage of a neurostimulation system can be programmed to steer different amounts of current through different stimulation electrodes to vary how strongly the tissue adjacent each electrode is stimulated during a particular programmed stimulation episode. An stimulation electrode drive circuit associated with each electrode that is available for stimulation allows independent control of the flow of current through that electrode. A reference electrode is provided in the circuit to source or sink current as necessary to balance the currents going into and out of the patient, so that no stimulation electrode is required to serve that purpose. More specifically, by configuring the circuit to maintain a constant potential at the reference electrode (e.g.

Abstract: An external data retrieval apparatus receives a low resolution version of a physiological signal from an active implantable medical device and determines if the physiological signal represents a clinically significant event. The apparatus provides an indication of such determination to the implantable medical device. If the physiological signal does represent a clinically significant event, the apparatus receives a full download of the physiological signal from the implantable device.

Abstract: A current management system for use in the stimulation output stage of a neurostimulation system can be programmed to steer different amounts of current through different stimulation electrodes to vary how strongly the tissue adjacent each electrode is stimulated during a particular programmed stimulation episode. An stimulation electrode drive circuit associated with each electrode that is available for stimulation allows independent control of the flow of current through that electrode. A reference electrode is provided in the circuit to source or sink current as necessary to balance the currents going into and out of the patient, so that no stimulation electrode is required to serve that purpose. More specifically, by configuring the circuit to maintain a constant potential at the reference electrode (e.g.

Abstract: Systems, methods and devices are disclosed for directing and focusing signals to the brain for neuromodulation and for directing and focusing signals or other energy from the brain for measurement, heat transfer and imaging. An aperture in the skull and/or a channel device implantable in the skull can be used to facilitate direction and focusing. Treatment and diagnosis of multiple neurological conditions may be facilitated with the disclosed systems, methods and devices.

Abstract: A system and method for estimating the current delivered to a patient during voltage-regulated electrical stimulation therapy by an implantable medical device includes calculating a total charge delivered and a peak current delivered and the time at which the peak current was delivered using a proxy for the current delivered to the patient and a component such as a current controlled oscillator, the output of which is proportional to the current proxy together with memory for storing values relating to the output proportional to the current proxy. The stored values also may be used to construct a waveform approximating the current delivered to the patient during a therapy of voltage-regulated stimulation. The system and method may be implemented in an active implantable medical device such as an implantable neurostimulator.

Abstract: A flexible antenna is associated with an active implantable medical device to facilitate communication between the implantable medical device and an external component in the outside world via, for example, long range or far field telemetry. The flexibility of the antenna allows it to conform to the shape of the location at which it is situated, such as on the cranial bone of a patient for an antenna associated with a cranially implanted medical device. The conformability of the antenna helps to maintain the antenna in the desired shape and to maintain it in the desired location relative to implantable medical device and the patient and improves patient comfort.

Abstract: Described herein are methods and systems for delivering a burst of stimulation pulses or pulse segments sequentially to a plurality of stimulation pathways. The stimulation pulses may be generated by a stimulation device, which may comprise an implantable neurostimulator. The stimulation pathways may comprise one or more electrodes electrically connected to the stimulation device. In some variations, the stimulation pathway may comprise a monopolar stimulation pathway and/or a bipolar stimulation pathway.

Abstract: A current management system for use in the stimulation output stage of a neurostimulation system can be programmed to steer different amounts of current through different stimulation electrodes to vary how strongly the tissue adjacent each electrode is stimulated during a particular programmed stimulation episode. An stimulation electrode drive circuit associated with each electrode that is available for stimulation allows independent control of the flow of current through that electrode. A reference electrode is provided in the circuit to source or sink current as necessary to balance the currents going into and out of the patient, so that no stimulation electrode is required to serve that purpose. More specifically, by configuring the circuit to maintain a constant potential at the reference electrode (e.g.

Abstract: A system and method for detecting and predicting neurological events with an implantable device uses a relatively low-power central processing unit in connection with signal processing circuitry to identify features (including half waves) and calculate window-based characteristics (including line lengths and areas under the curve of the waveform) in an electrographic signal received from a patient's brain. The features and window-based characteristics are combinable in various ways according to the invention to detect and predict neurological events in real time, enabling responsive action by the implantable device.

Abstract: A system and method for detecting and predicting neurological events with an implantable device uses a relatively low-power central processing unit in connection with signal processing circuitry to identify features (including half waves) and calculate window-based characteristics (including line lengths and areas under the curve of the waveform) in an electrographic signal received from a patient's brain. The features and window-based characteristics are combinable in various ways according to the invention to detect and predict neurological events in real time, enabling responsive action by the implantable device.

Abstract: A system and method for detecting and predicting neurological events with an implantable device uses a relatively low-power central processing unit in connection with signal processing circuitry to identify features (including half waves) and calculate window-based characteristics (including line lengths and areas under the curve of the waveform) in an electrographic signal received from a patient's brain. The features and window-based characteristics are combinable in various ways according to the invention to detect and predict neurological events in real time, enabling responsive action by the implantable device.

Abstract: An implantable multimodal neurostimulator having improved efficacy in treating epilepsy and other neurological disorders and processes of using that neurostimulator are described herein. The neurostimulator itself generally has two modes of electrical stimulation. The first involves delivering a non-responsive electrical stimulation signal that is applied to the central nervous system to reduce the likelihood of a seizure or other undesirable neurological even from occurring. Various waveform morphologies are described for non-responsive stimulation signals. A second mode involves delivering a responsive electrical stimulation signal when epileptiform waveforms are impending or extant. The responsive electrical stimulation signal is intended to terminate epileptiform activity, e.g., to desynchronize abnormally synchronous brain electrical activity.

Abstract: A system and method for detecting and predicting neurological events with an implantable device uses a relatively low-power central processing unit in connection with signal processing circuitry to identify features (including half waves) and calculate window-based characteristics (including line lengths and areas under the curve of the waveform) in an electrographic signal received from a patient's brain. The features and window-based characteristics are combinable in various ways according to the invention to detect and predict neurological events in real time, enabling responsive action by the implantable device.

Abstract: An implantable device incorporating an acoustic transducer allows information and alerts to be communicated from the device to a patient. Sounds, including but not limited to buzzes, tones, sequences of tones, combinations of tones, complex sounds, and segments of reproduced or simulated human speech, are transmitted from an intracranially implanted portion of the device via bone conduction to the patient's ears, particularly the inner ears. In the disclosed embodiment, the acoustic transducer is used in cooperation with an implantable closed-loop system for the treatment of certain neurological disorders such as epilepsy, migraine headaches and Parkinson's disease, to warn the patient of an imminent seizure or other episode, to provide information to the patient on the state of the implantable apparatus, and to provide reminders and other information to the patient.

Abstract: An implantable multimodal neurostimulator having improved efficacy in treating epilepsy and other neurological disorders and processes of using that neurostimulator are described herein. The neurostimulator itself generally has two modes of electrical stimulation. The first involves delivering a non-responsive electrical stimulation signal that is applied to the central nervous system to reduce the likelihood of a seizure or other undesirable neurological even from occurring. Various waveform morphologies are described for non-responsive stimulation signals. A second mode involves delivering a responsive electrical stimulation signal when epileptiform waveforms are impending or extant. The responsive electrical stimulation signal is intended to terminate epileptiform activity, e.g., to desynchronize abnormally synchronous brain electrical activity.

Abstract: An implantable device incorporating an acoustic transducer allows information and alerts to be communicated from the device to a patient. Sounds, including but not limited to buzzes, tones, sequences of tones, combinations of tones, complex sounds, and segments of reproduced or simulated human speech, are transmitted from an intracranially implanted portion of the device via bone conduction to the patient's ears, particularly the inner ears. In the disclosed embodiment, the acoustic transducer is used in cooperation with an implantable closed-loop system for the treatment of certain neurological disorders such as epilepsy, migraine headaches and Parkinson's disease, to warn the patient of an imminent seizure or other episode, to provide information to the patient on the state of the implantable apparatus, and to provide reminders and other information to the patient.

Abstract: An active overload detection and protection circuit for protecting a host device (e.g., an implantable cardiac therapy device) from potential damage due to high voltage transients applied to an I/O node thereof. The protection circuit includes an I/O circuit coupled to the I/O node, the I/O circuit having low-impedance and high-impedance modes, a current overload detection circuit coupled to the I/O circuit which detects a current overload condition induced by a high voltage transient, and which generates an overload detect signal in response, and, a mode changing circuit which changes the mode of the I/O circuit from the low-impedance mode to the high-impedance mode in response to the overload detect signal. The protection circuit further includes a reset circuit which generates a reset signal a prescribed time after the overload detect signal is generated, wherein the mode changing circuit is responsive to the reset signal to change the mode of the I/O circuit.

Abstract: A method for ensuring two-sided telemetry in implantable cardiac therapy devices by making at least one of the following operating parameters selectable (reversible): (1) the direction of current detection of the telemetry circuitry of the implantable cardiac therapy device; (2) the direction of the magnetic field produced by the transmit coil of an external telemetry device (programming wand); (3) the direction of the magnetic field produced by the T/R coil of the implantable cardiac therapy device; and/or (4) the direction of current detection of the telemetry circuitry of the programming wand. In a presently contemplated implementation, when it is desired to read-out data from the implantable cardiac therapy device and/or to re-program the device parameters, a telemetry operation is attempted in the normal manner, i.e., it is initiated by the programming wand.

Abstract: In a power supply circuit supplying a high voltage charger of an implantable cardioverter-defibrillator (ICD), a changer circuit switches the power source of the power supply circuit between a battery and an output signal of a step-up converter. The signal derived from the boost winding rises to a high voltage when the high voltage charger charges the storage capacitors of the ICD. A system current measurement circuit can be provided in the power supply circuit.

Abstract: A high voltage charger operates in a three-phase cycle. In a first phase, the high voltage charger operates at a fixed frequency. In a second phase, the high voltage charger operates at a variable frequency designed to draw a substantially constant average current from a power source. In the third phase, the high voltage charger returns to fixed frequency operation. The variable frequency is the reciprocal of the sum of an on-time and an off-time of the switch. In one embodiment, the on-time is provided by the time required for the switch to reach a predetermined maximum and the off-time is provided by the time over which a magnetic field in a transformer collapses.