Devices and Methods for Stimulating Neural Tissue

An automated method of controllably delivering neural stimuli to a neural pathway of a patient, the method comprising:

• delivering a neural stimulus to the neural pathway of the patient in order to evoke a neural response from the neural pathway, the neural stimulus being delivered according to a stimulus intensity parameter via one or more stimulus electrodes;
• capturing a signal window from a signal sensed on the neural pathway subsequent to the delivered neural stimulus;
• measuring an intensity of a neural response evoked by the delivered neural stimulus in the captured signal window;
• computing, from the measured intensity of the evoked neural response, a feedback variable;
• adjusting the stimulus intensity parameter so as to maintain the feedback variable at a target response intensity;
• estimating an out-of-compliance current limit for each of the one or more stimulus electrodes;
• estimating a closed-loop current requirement;
• comparing the out-of-compliance current limit for each of the one or more stimulus electrodes to the closed-loop current requirement;
• and
• taking a mitigating action based on the comparison.

A neural stimulation system comprising:

• an implantable closed-loop neural stimulation device for controllably delivering neural stimuli via one or more stimulus electrodes, the device comprising 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.

A neural stimulation system comprising:

• an implantable device for controllably delivering neural stimuli, the device comprising:
• a plurality of electrodes including one or more stimulus electrodes:
• a stimulus source configured to provide neural stimuli to be delivered via the one or more stimulus electrodes to a neural pathway of a patient;
• and
• a control unit configured to:
• control the stimulus source to provide a neural stimulus according to a stimulus current and a further stimulus parameter;
• and
• a processor configured to:
• estimate an out-of-compliance current limit for each of the one or more stimulus electrodes:
• and
• choose a value for the further stimulus parameter such that the out-of-compliance current limit for each of the one or more stimulus electrodes exceeds a maximum value of the stimulus current.

An automated method of controllably delivering neural stimuli to a neural pathway of a patient, the method comprising:

• delivering a neural stimulus to the neural pathway of the patient in order to evoke a neural response from the neural pathway, the neural stimulus being delivered according to a stimulus current and a further stimulus parameter via one or more stimulus electrodes;
• estimating an out-of-compliance current limit for each of the one or more stimulus electrodes;
• and
• choosing a value for the further stimulus parameter such that the out-of-compliance current limit for each of the one or more stimulus electrodes is likely to exceed a maximum value of the stimulus current.