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 applies and controls a neural stimulus. The device has a plurality of electrodes, and a stimulus source for providing a stimulus to be delivered from the electrodes to a neural pathway in order to evoke an action potential on the neural pathway, such as the spinal cord. A control unit controls application of a neural stimulus as defined by a set of parameter values and measures via measurement circuitry an evoked neural compound action potential response. The control unit determines from the measured evoked response a feedback variable, and compares it to a therapy map. The therapy map defines a therapeutic relationship of control variable to feedback variable. One or more of the stimulus parameter values are altered to effect the required change in the control variable. This process is performed iteratively to improve alignment of the feedback variable with the therapy map over time.

Abstract: An implantable device for monitoring for neural injury has a plurality of electrodes including stimulus electrodes and sense electrodes. A stimulus source provides a stimulus to be delivered to a nerve in order to give rise to an evoked action potential. Measurement circuitry records a neural compound action potential signal sensed at the sense electrodes. A stream of control stimuli are applied to the nerve over time and the evoked neural responses are measured. A diagnostic parameter of the measured neural responses is monitored over time, in order to detect a change in the diagnostic parameter. If a change in the diagnostic parameter occurs over time, an indication is output that neural injury has occurred.

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: 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 fiber 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 fiber population. Using an electrode array and suitable relative timing of the stimuli, ascending or descending volleys of evoked responses can be selectively synchronized or desynchronized to give directional control over responses evoked.

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 determining a desired location at which to apply a neural therapy. An array of electrodes is positioned proximal to neural tissue. A stimulus is applied from the array which evokes a neural compound action potential response in the neural tissue proximal to the array. A plurality of electrodes of the array simultaneously obtain respective measurements of the neural compound action potential response. From the measurements of the neural compound action potential response a desired location for a neural therapy is determined.

Abstract: An electrode assembly for an active implantable medical device can be delivered by catheter but expands to become a paddle electrode once implanted. The electrode assembly comprises a support member carrying wires for electrically connecting a control unit to electrodes of the electrode assembly. At least one, and usually two resilient deformable paddle wings are mounted to the support member. The paddle wings can be furled close to the support member under a deformation force to permit implantation via an introducer. The paddle wings resiliently unfurl away from the support member upon release of the deformation force. The paddle wings bear rows and columns of electrodes, and the electrode assembly as a whole has sufficient longitudinal rigidity for implantation via an introducer.

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: A method for estimating conduction velocity of a neural response. Measurements of the neural response are obtained from at least two electrodes which are at distinct locations along a neural pathway. A delay between the time of arrival of the neural response at each respective electrode is determined from the measurements. From the delay, and from knowledge of electrode spacing, a conduction velocity of the neural response is estimated.

Abstract: An implantable device applies and controls a neural stimulus. The device has a plurality of electrodes, and a stimulus source for providing a stimulus to be delivered from the electrodes to a neural pathway in order to evoke an action potential on the neural pathway, such as the spinal cord. A control unit controls application of a neural stimulus as defined by a set of parameter values and measures via measurement circuitry an evoked neural compound action potential response. The control unit determines from the measured evoked response a feedback variable, and compares it to a therapy map. The therapy map defines a therapeutic relationship of control variable to feedback variable. One or more of the stimulus parameter values are altered to effect the required change in the control variable. This process is performed iteratively to improve alignment of the feedback variable with the therapy map over time.

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.