Abstract: A method (100) of manufacturing a lead for an implantable medical device. The method includes: depositing (110) a base layer (3) of biocompatible, electrically non-conductive material; depositing (120) one or more complementary layers (5) of biocompatible, electrically non-conductive material to the base layer (3), wherein the base layer (3) and complementary layer (5) form at least one slot (7); and depositing (130) biocompatible, electrically conductive material (9) into the slot (7). There is also disclosed a lead for an implantable medical device and an apparatus (41) to manufacture the lead.

Abstract: An electrode assembly (1) for an active implantable medical device comprising: an elongated, biocompatible, electrically non-conductive body (3) having a first portion (7) and a second portion (9); one or more biocompatible, electrically conductive filaments (5) inside the elongated non-conductive body (3) between the first portion (7) and the second portion (9); and one or more fluid passages (11) along the elongated electrically non-conductive body (3) between the first portion (7) and second portion (9), wherein the one or more fluid passages (11) allow a surrounding fluid (13) of a patient to be in electrical contact with the one or more conductive filaments (5). There is also disclosed a method of manufacturing an electrode assembly.

Abstract: A method for measuring a neural response to a stimulus. Measurement circuitry is settled prior to a stimulus, by connecting a sense electrode to the measurement circuitry to allow the measurement circuitry to settle towards a bio-electrically defined steady state. Charge is recovered on stimulus electrodes by short circuiting the stimulus electrodes to each other. An electrical stimulus is then applied from the stimulus electrodes to neural tissue, while keeping the sense electrode disconnected from the measurement circuitry. After the stimulus, a delay is imposed during which the stimulus electrodes are open circuited and the sense electrode is disconnected from the measurement circuitry and from the stimulus electrodes. After the delay, a neural response signal present at the sense electrode is measured by connecting the sense electrode to the measurement circuitry.

Abstract: A method for measuring a neural response to a stimulus. Measurement circuitry is settled prior to a stimulus, by connecting a sense electrode to the measurement circuitry to allow the measurement circuitry to settle towards a bio-electrically defined steady state. Charge is recovered on stimulus electrodes by short circuiting the stimulus electrodes to each other. An electrical stimulus is then applied from the stimulus electrodes to neural tissue, while keeping the sense electrode disconnected from the measurement circuitry. After the stimulus, a delay is imposed during which the stimulus electrodes are open circuited and the sense electrode is disconnected from the measurement circuitry and from the stimulus electrodes. After the delay, a neural response signal present at the sense electrode is measured by connecting the sense electrode to the measurement circuitry.

Abstract: An implantable device for estimating neural recruitment arising from a stimulus, has a plurality of electrodes. A stimulus source provides stimuli to be delivered from the electrodes to neural tissue. Measurement circuitry obtains a measurement of a neural signal sensed at the electrodes. A control unit is configured to control application of a selected stimulus to neural tissue using the stimulus electrodes; and after the selected neural stimulus, apply a probe stimulus having a short pulse width. A remnant neural response evoked by the probe stimulus is measured; and the control unit estimates from the remnant neural response a neural recruitment caused by the selected neural stimulus.

Abstract: A method is provided for processing a neural measurement obtained in the presence of noise, in order to detect whether a locally evoked neural response is present in the neural measurement. A first neural measurement is obtained from a first sense electrode. A second neural measurement is contemporaneously obtained from a second sense electrode spaced apart from the first electrode along a neural pathway of the neural response. A neural response decay is determined, being a measure of the decay in the neural response from the first sense electrode to the second sense electrode. A ratio of the neural response decay to an amplitude normalising term is calculated. From the ratio it is determined whether a locally evoked neural response is present in the neural measurement.

Abstract: Communications along a neural pathway are provided. The neural pathway is stimulated at a first location, in order to evoke neural responses which propagate along the neural pathway, the neural responses being modulated with data. At a second location spaced apart from the first location along the neural pathway the evoked neural responses are sensed. The sensed neural responses are then demodulated to retrieve the data. The stimulation could comprise peripheral sensory stimulation, and the second location could be at an implanted electrode array.

Abstract: A method of surgically positioning an electrode array at a desired implantation location relative to a nerve. A temporary probe electrode is temporarily positioned adjacent to the nerve and at a location which is caudorostrally separate to the desired implantation location of the electrode array. The implanted position of the probe electrode is temporarily fixed relative to the nerve. During implantation of the electrode array, electrical stimuli are applied from one of the temporarily fixed probe electrode and the electrode array, to evoke compound action potentials on the nerve. Compound action potentials evoked by the stimuli are sensed from at least one electrode of the other of the temporarily fixed probe electrode and the electrode array. From the sensed compound action potentials a position of the electrode array relative to the nerve is determined.

Abstract: An implantable device for estimating neural recruitment arising from a stimulus, has a plurality of electrodes. A stimulus source provides stimuli to be delivered from the electrodes to neural tissue. Measurement circuitry obtains a measurement of a neural signal sensed at the electrodes. A control unit is configured to control application of a selected stimulus to neural tissue using the stimulus electrodes; and after the selected neural stimulus, apply a probe stimulus having a short pulse Width. A remnant neural response evoked by the probe stimulus is measured; and the control unit estimates from the remnant neural response a neural recruitment caused by the selected neural stimulus.

Abstract: A motor response of a muscle to neural stimulation is assessed. Electrical stimuli are applied from a first electrode to a selected neural pathway to evoke an efferent neural response. A slow neural response upon the neural pathway evoked by the electrical stimuli is observed. Based on the slow neural response, a motor response of at least one muscle to the stimuli is assessed.

Abstract: Fitting a brain neurostimulator electrode array comprises positioning at least a first electrode in a desired target structure in a first cerebral hemisphere, and positioning at least a second electrode in a corresponding target structure in a contralateral cerebral hemisphere. Electrical stimuli are applied from the first electrode to the desired target structure. Neural responses observed at the second electrode in response to the electrical stimuli are recorded. The fitting of at least one of the first electrode and second electrode is assessed by reference to the recorded neural responses.

Abstract: Monitoring brain neural activity comprises repeatedly applying electrical stimuli to evoke neural responses in the brain. Neural responses evoked by the stimuli are recorded. The recorded neural responses are assessed for changed characteristics over time, to monitor a time-varying effect on the recorded neural responses of local field potentials arising from a source other than the electrical stimuli.

Abstract: A method of applying a neural stimulus with an implanted electrode array involves applying a sequence of stimuli configured to yield a therapeutic effect while suppressing psychophysical side effects. The stimuli sequence is configured such that a first stimulus recruits a portion of the fibre population, and a second stimulus is delivered within the refractory period following the first stimulus and the second stimulus being configured to recruit a further portion of the fibre population. Using an electrode array and suitable relative timing of the stimuli, ascending or descending volleys of evoked responses can be selectively synchronised or desynchronised to give directional control over responses evoked.

Abstract: Estimating a nerve-to-electrode distance involves applying a stimulus from a stimulus electrode to a nerve. Neural measurements of at least one evoked compound action potential are obtained, and processed in order to estimate an originating state of stimulation exhibiting at least one characteristic defined by a single fibre size. A single fibre model is then applied to produce a measure of the nerve-to-electrode distance. Also provided for is estimation of a distribution of recruited fibres. Measurements of a compound action potential are obtained from sense electrodes spaced apart along a neural pathway. A conduction velocity of the compound action potential is determined from the latency between the measurements. From the conduction velocity a dominant recruited fibre diameter is determined. A rate of dispersion of the compound action potential between the sense electrodes is determined. From the rate of dispersion a distribution of diameters of the recruited fibre population is determined.

Abstract: A method of applying a neural stimulus with an implanted electrode array involves applying a sequence of stimuli configured to yield a therapeutic effect while suppressing psychophysical side effects. The stimuli sequence is configured such that a first stimulus recruits a portion of the fibre population, and a second stimulus is delivered within the refractory period following the first stimulus and the second stimulus being configured to recruit a further portion of the fibre population. Using an electrode array and suitable relative timing of the stimuli, ascending or descending volleys of evoked responses can be selectively synchronised or desynchronised to give directional control over responses evoked.

Abstract: Applying therapeutic neural stimuli involves monitoring for at least one of sensory input and movement of a user. In response to detection of sensory input or user movement, an increased stimulus dosage is delivered within a period of time corresponding to a duration of time for which the detected sensory input or user movement gives rise to masking, the increased stimulus dosage being configured to give rise to increased neural recruitment.

Abstract: The neural health or state of a subject is assessed. A recording is obtained of a compound action potential arising in neural tissue of the subject. The recording is processed to determine whether a profile of the recorded compound action potential is anomalous, such as by exhibiting doublets, peak broadening or deformation, or other anomaly. An indication is output regarding the neural state of the subject based on determined anomalies in the recorded compound action potential.

Abstract: A method for measuring a neural response to a stimulus. Measurement circuitry is settled prior to a stimulus, by connecting a sense electrode to the measurement circuitry to allow the measurement circuitry to settle towards a bio-electrically defined steady state. Charge is recovered on stimulus electrodes by short circuiting the stimulus electrodes to each other. An electrical stimulus is then applied from the stimulus electrodes to neural tissue, while keeping the sense electrode disconnected from the measurement circuitry. After the stimulus, a delay is imposed during which the stimulus electrodes are open circuited and the sense electrode is disconnected from the measurement circuitry and from the stimulus electrodes. After the delay, a neural response signal present at the sense electrode is measured by connecting the sense electrode to the measurement circuitry.

Abstract: A method of applying a neural stimulus with an implanted electrode array involves applying a sequence of stimuli configured to yield a therapeutic effect while suppressing psychophysical side effects. The stimuli sequence is configured such that a first stimulus recruits a portion of the fibre population, and a second stimulus is delivered within the refractory period following the first stimulus and the second stimulus being configured to recruit a further portion of the fibre population. Using an electrode array and suitable relative timing of the stimuli, ascending or descending volleys of evoked responses can be selectively synchronised or desynchronised to give directional control over responses evoked.

Abstract: Neural activity in the brain arising from a stimulus is monitored. A stimulus is applied to a target structure of the brain and a neural measurement is obtained from at least one electrode implanted in contact with the target structure. The neural measurement is configured to capture a measure of any late response arising in the target structure, typically being a neural response arising after conclusion of an ECAP, such as in the period 1.5-10 ms after stimulus onset. The late response(s) can be a useful biomarker such as of therapeutic ranges of deep brain stimulation, disease progression, medication efficacy, and intra-operative changes.