Saluda Medical Pty Ltd

A method of controlling a neural stimulus, the neural stimulus being defined by at least one stimulus intensity parameter. The method comprises, generating a stimulus intensity parameter to control a stimulator that generates a stimulus current for application to a tissue, measuring a response of the tissue, evoked by the stimulus current, determining a response parameter indicative of the measured response, in response to the response parameter being less than a first threshold, setting the stimulus intensity parameter to a desired stimulus intensity level; and in response to the response parameter being greater than a second threshold, adjust the stimulus intensity parameter according to a feedback variable derived from the measured response.

A neuromodulation device comprises stimulus electrodes and sense electrodes. A stimulus source provides stimuli to evoke a neural response on a neural pathway. A signal sensed at the sense electrodes includes an evoked neural response. A control unit controls the stimulus source to provide the neural stimulus according to a stimulus intensity parameter; measures an intensity of the evoked response; and completes a feedback loop using the measured intensity and controller parameters to control the stimulus intensity parameter to maintain the measured intensity at a target value. Optimal values of the controller parameters are determined from a representative value of a characteristic of the feedback loop, the representative value having been derived from data of previously programmed patients, and/or the processor is configured to determine optimal values of the one or more controller parameters from a predetermined value of an amplification parameter of the feedback loop.

In some implementations, the device may include a neural stimulation system having: an implantable closed-loop neural stimulation device for controllably delivering neural stimuli via one or more stimulus electrodes, the device having the one or more stimulus electrodes and a feedback controller configured to adjust a stimulus intensity parameter so as to maintain a measured neural response intensity at a target response intensity; and a processor configured to: estimate an out-of-compliance current limit for each of the one or more stimulus electrodes; estimate a closed-loop current requirement for the implantable closed-loop neural stimulation device; compare the out-of-compliance current limit for each of the one or more stimulus electrodes to the closed-loop current requirement; and take a mitigating action based on the comparison.

Controlling a neural stimulus comprises applying the neural stimulus to a neural pathway in order to give rise to an evoked action potential on the neural pathway, the stimulus being defined by at least one stimulus parameter. A neural compound action potential response evoked by the stimulus is measured, and from the measured evoked response a feedback variable is derived. Loop backoff behaviour is adjusted by applying a non-identity function to the feedback variable to produce a revised feedback variable, and completing a feedback loop by using the revised feedback variable to control the at least one stimulus parameter so as to maintain the feedback variable at a setpoint. Additionally, or alternatively, loop gain can be adjusted in response to a change in the loop setpoint, and/or a logarithm of the stimulus parameter can be controlled.

A neuromodulation device comprises stimulus electrodes and sense electrodes. A stimulus source provides stimuli to evoke a neural response on a neural pathway. A signal sensed at the sense electrodes includes an evoked neural response. A control unit controls the stimulus source to provide the neural stimulus according to a stimulus intensity parameter; measures an intensity of the evoked response; and completes a feedback loop using the measured intensity and controller parameters to control the stimulus intensity parameter to maintain the measured intensity at a target value. Optimal values of the controller parameters are determined from a representative value of a characteristic of the feedback loop, the representative value having been derived from data of previously programmed patients, and/or the processor is configured to determine optimal values of the one or more controller parameters from a predetermined value of an amplification parameter of the feedback loop.

This disclosure relates to a device for applying a neural stimulus. A battery supplies electrical energy at a battery voltage and an electrode applies the electrical energy to neural tissue. A circuit measures the nervous response of the tissue and a voltage converter receives the electrical energy from the battery and controls a voltage applied to the electrode based on the measured nervous response of the tissue. This direct voltage control is energy efficient because losses across a typical current mirror are avoided. Further, the control based on the measured nervous response leads to automatic compensation of impedance variation due to in-growth or change in posture. As a result, the stimulation results in a desired neural response.

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.

A neural stimulus comprises at least three stimulus components, each comprising at least one of a temporal stimulus phase and a spatial stimulus pole. A first stimulus component delivers a first charge which is unequal to a third charge delivered by a third stimulus component, and the first charge and third charge are selected so as to give rise to reduced artefact at recording electrodes. In turn this may be exploited to independently control a correlation delay of a vector detector and an artefact vector to be non-parallel or orthogonal.

This disclosure relates to an implantable electric circuit ( 300 ) for medical stimulation The circuit comprises a plurality of capacitors ( 301 ) and a network of resistors ( 302 ). Each of the plurality of capacitors ( 301 ) is configured to couple radio frequency energy from one of a plurality of electrically conductive filaments ( 5 ) of a lead to the network of resistors ( 302 ). Further, the network of resistors ( 302 ) is configured to connect the plurality of capacitors ( 301 ) together to dissipate the radio frequency energy between the plurality of electrically conductive filaments. The network of resistors dissipates the energy between the filaments, which reduces negative impacts for the patient when subjected to MRI imaging. Further, no ground is required and as a result, the circuit can be placed into a header of an implantable pulse generator or into the lead itself.

An implantable neural stimulation device is provided, comprising a body containing stimulation electronics, and a battery to provide stimulation energy, a lid, coupled to the body, the lid configured to at least partially seal the body and a header coupled to the body of the device. The header comprises a contact assembly electrically coupled to the stimulation electronics via at least one feedthrough wire extending through the lid, the contact assembly configured to connect to a stimulation lead to deliver the stimulation energy from the battery under control by the stimulation electronics, a charge coil configured to charge the battery, and a support component configured to support the charge coil. The support component is supported in position by the contact assembly.