A lead body is operable to be implanted proximate a target nerve tissue of a patient. A sensing electrode is configured to sense biopotentials over a first partial circumference of the lead body. A stimulation electrode is configured to deliver stimulation energy over a second partial circumference of the lead body. A signal generator is electrically coupled to the stimulation electrode and a sensing circuit is coupled to the sensing electrode. A processor is operable to apply a stimulation signal to the stimulation electrode via the signal generator and, via the sensing circuit, sense an evoked response to the stimulation signal that propagates along a neural pathway.

Methods and systems are disclosed for modulating glycaemia in a patient in which an activating stimulation signal is applied at an activating location at the vagus nerve, the activating stimulation signal configured to evoke a neural response in the vagus nerve; and a blocking stimulation signal is applied at a blocking location at the vagus nerve, the blocking stimulation signal configured to inhibit transmission of the evoked neural response along the vagus nerve past the blocking location; to produce unidirectional vagal nerve stimulation, the unidirectional vagal nerve stimulation being effective to modulate glycaemia in the patient.

Intraoral appliances are disclosed that provide electrical stimulation to tissue in a patient's oral cavity in a manner that reduces apnea events during sleep. A representative appliance can induce a current or currents through tissue and/or anatomical structures in a manner that maintains upper airway tone and/or patency.

Disclosed is a method of adapting the operation of an implantable device for delivering neurostimulation therapy to a patient. The method comprises: delivering the neurostimulation therapy to electrically excitable tissue of the patient according to at least one therapy parameter; measuring a physiological characteristic of the patient; adjusting the at least one therapy parameter according to a schedule of adjustment and the measured physiological characteristic; and repeating the delivering, measuring, and adjusting.

An Implantable Pulse Generator (IPG) is disclosed that is capable of sensing a degree to which recruited neurons in a patient's tissue are firing synchronously, and of modifying a stimulation program to promote desynchronicity and to reduce paresthesia. An evoked compound action potential (ECAP) of the recruited neurons is sensed as a measure of synchronicity by at least one non-active electrode. An ECAP algorithm operable in the IPG assesses the shape of the ECAP and determines one or more ECAP shape parameters that indicate whether the recruited neurons are firing synchronously or desynchronously. If the shape parameters indicate significant synchronicity, the ECAP algorithm can adjust the stimulation program to promote desynchronous firing.

Sense amplifier circuits particularly useful in sensing neural responses in an Implantable Pulse Generator (IPG) are disclosed. The IPG includes a plurality of electrodes, with one selected as a sensing electrode and another selected as a reference to differentially sense the neural response in a manner that subtracts a common mode voltage (e.g., stimulation artifact) from the measurement. The circuits include a differential amplifier which receives the selected electrodes at its inputs, and comparator circuitries to assess each differential amplifier input to determine whether it is of a magnitude that is consistent with the differential amplifier's input requirements. Based on these determinations, an enable signal is generated which informs whether the output of the differential amplifier validly provides the neural response at any point in time. Further, clamping circuits are connected to the differential amplifier inputs to clamp these inputs in magnitude to prevent the differential amplifier from damage.

A system can utilize interleaving periods or waveforms to stimulate patient tissue and sense signals using the stimulation electrodes. For example, the system can utilize alternating therapeutic periods and sensing periods. As another example, the system can alternate between biphasic waveforms having opposite temporal orders of positive and negative phases. As another example, waveforms that differ in a parameter, such as amplitude or pulse width, can be interleaved to provide different information in the respective sensed signals.

An example method includes receiving one or more physiological signals; detecting an apnea event based on the one or more physiological signals; determining that the apnea event cannot be characterized as one of a normal, OSA (obstructive sleep apnea), CSA (central sleep apnea), or combination OSA/CSA event; and outputting an electrical stimulation as a default based on determining that the apnea event cannot be characterized as a normal event, an OSA event, a CSA event, or combination OSA/CSA events.

Devices, systems, and techniques are disclosed for determining spatial relationships between electrodes implanted within a patient. In one example, a medical device delivers, via a first electrode, an electrical stimulus and senses, for each other electrode, a respective electrical signal indicative of the electrical stimulus. The medical device determines, for each other electrode, a respective value for each respective electrical signal. The medical device determines, based on the respective values for each respective electrical signal and values of tissue conductivity of tissues of the patient interposed between the first electrode and the other electrodes, spatial relationships between the first electrode and each other electrode of the plurality of electrodes.

Devices and methods to effectuate closed loop electrical stimulation of nerve tissue, based on feedback data, to mitigate pain of a patient are disclosed. Feedback data corresponding to bioelectric signals of neurons stimulated by stimulation pulses may be received and analyzed. Based on receipt of the feedback data, it may be determined to modify one or more stimulation parameters, corresponding to the stimulation pulses, to enhance an efficacy of the stimulation pulses at blocking generation and/or propagation of one or more pain signals through a neuroanatomy of the patient. Subsequent and additional stimulation pulses may be provided based on a modified set of stimulation parameters and configured to enhance attenuation of generation and/or transmission of pain signals through the neuroanatomy of the patient to ultimately reduce a level of pain experienced by the patient.