Embodiments are directed to an implantable medical device comprising therapeutic stimulation circuitry for controlling delivery of a medical therapy to a patient, the therapeutic stimulation circuitry having at least one lead having electrodes for delivering the medical therapy. The implantable medical device further comprises measurement circuitry for determining characteristics of the at least one lead, a processor for controlling the IMD according to executable code, and memory for storing data and executable code, wherein the executable code comprises instructions for causing the processor to receive a plurality of voltage measurements associated with the electrodes, and calculate values for an impedance model of the electrode/tissue interface.

A closed loop control system automatically ensures that an output of a device is constant. The system can receive an input to set a fixed value for a variable (e.g., a current, a heart rate, a tissue perfusion, an ion level, etc.), and this variable can be delivered to a feedback component. The system can also include the device to deliver the variable to a load. The feedback component can be coupled to the delivery device to sample the output of the delivery device at different times. Based on the sampling, the feedback component can vary a property of the delivery device related to the delivery of the variable to the load to ensure that the variable remains constant at the fixed value. In some instances, the system can be implemented as a stimulator that delivers the constant current of a current source and has a low output impedance of a voltage source.

In some examples, a technique for delivering electrical stimulation therapy to a patient includes determining, by processing circuitry, one or more cycle settings associated with delivery of the electrical stimulation therapy, determining, by the processing circuitry, a cycle time period associated with each cycle setting, and delivering, by a medical device, electrical stimulation therapy based on the determined cycle settings and the determined cycle time periods. Each cycle setting may define an on-cycle, during which electrical stimulation is delivered, and an off-cycle, during which electrical stimulation is not delivered. The technique further may include delivering electrical stimulation to the patient to provide one or more reminders to the patient, such as a reminder to void or a reminder of the existence of electrical stimulation.

Techniques to help improve efficiency or effectiveness of treating a disorder such as RLS or PLMD, such as by issuing neural electrostimulations to a particular patient, while varying one or more amplitude parameters (e.g., at least one of electrostimulation current amplitude, electrostimulation voltage amplitude, or electrostimulation pulsewidth duration). A corresponding patient-subjective or patient-objective response can be observed. A characteristic electrostimulation intensity relationship can be generated, for example, based on the determined respective at least one of RLS or PLMD response indication threshold amplitude parameters and the plurality of corresponding neural electrostimulation durations. Once this characteristic electrostimulation intensity relationship has been generated, it can then be used to control issuing subsequent neural electrostimulations to the particular patient according to (1) at least one goal and (2) a variable operating point based upon the generated characteristic electrostimulation intensity relationship.

Systems and methods are provided for delivering neurostimulation therapies to patients. Stimulation from an implantable medical device (IMD) may be suspended in response to detecting a patient discomfort event, such as a cough, throat irritation, or voice alteration. The suspension period may be based on at least one of a severity level of the patient discomfort event and a patient physical state, such as being asleep or lying down. Detection of a patient discomfort event may be calibrated.

The techniques described herein are example medical devices, systems, and methods for sensing evoked potentials in a tissue of the patient, and, based on the sensed evoked potentials, adjusting one or more parameters defining the electrical stimulation therapy delivered to the patient. In one example, a system controls delivery of an electrical stimulation therapy from an implantable medical device to a patient according to at least one therapy program, wherein the electrical stimulation therapy is configured to provide pain relief to the patient without substantially resulting in paresthesia perceived by the patient. The system periodically adjusts the electrical stimulation therapy delivered to the patient in response to detected compound action potentials, wherein the adjustment to the electrical stimulation therapy is configured to eliminate action potentials in tissue of the patient evoked by the delivered electrical stimulation, and wherein the controlling and the adjusting are performed via one or more processors.

In some examples of selecting a target therapy delivery site for treating a patient condition, a relatively high frequency electrical stimulation signal is delivered to at least two areas within a first region (e.g., an anterior nucleus of the thalamus) of a brain of a patient, and changes in brain activity (e.g., as indicated by bioelectrical brain signals) within a second region (e.g., a hippocampus) of the brain of the patient in response to the delivered stimulation are determined. The target therapy delivery site, an electrode combination, or both, may be selected based on the changes in brain activity.

A system and method for extracting ETI load parametric data relative to one or more electrodes of an implanted stimulation lead system associated with an IPG. A Kelvin connection scheme is provided for measuring induced voltages present at stimulated electrodes during a stimulation ramping sequence, which may be used for determining the ETI parametric data using a number of techniques, including, without limitation, a waveform analysis.

A neuromodulation system and method with feedback optimized electrical field generation for stimulating target tissue of a patient to treat neurological and non-neurological conditions. The system generally includes implantable electrodes, implantable sensors, an implantable or external electrical signal generator, and an implantable or external controller. The controller controls the electrical signal generator to generate electrical noise stimulation signals that are delivered to the target tissue via the electrodes and that produce an optimized electric field having maximized voltage with low current density. The sensors produce temperature and impedance data for the target tissue and the controller automatically responds to values of the sensor data that indicate potential damage to the target tissue to reduce the strength of the electric field.

Apnea events may be detected based on a primary biomarker, e.g., respiration, in the one or more physiological signals. The apnea events may be characterized as one of an obstructive sleep apnea (OSA) event, a central sleep apnea (CSA) event, or a combination OSA/CSA event based on a secondary biomarker, e.g., a frequency spectrum or a morphology of the respirations in the one or more physiological signals. A first electrical stimulation may be provided to treat OSA in response to a first one or more of the apnea events being characterized as OSA events. A second electrical stimulation may be provided to treat CSA in response to a second one or more of apnea events being characterized as CSA events. A third electrical stimulation may be provided to treat combination OSA/CSA in response to a third one or more of the apnea events being characterized as combination OSA/CSA events.