Neural stimulation system providing auto adjustment of stimulus output as a function of sensed impedance
First Claim
1. A method of neural stimulation using a neurostimulator, the method comprising:
- correlating impedance changes with predicted stimulation energy adjustments;
initially storing the correlated measured impedance changes and predicted stimulation energy adjustments in a look-up table;
measuring a change in impedance indicative of variations in the coupling efficiency between stimulation energy output from the neurostimulator and neural tissue;
subsequently analyzing the stored correlated measured impedance changes and predicted stimulation energy adjustments to determine the predicted stimulation energy adjustment correlated to the measured impedance change; and
automatically adjusting the stimulation energy output from the neurostimulator accordance with the determined stimulation energy adjustment to compensate for the variations in the coupling efficiency by maintaining the stimulation energy delivered to the neural tissue at a set level.
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Accused Products
Abstract
A neural stimulation system automatically corrects or adjusts the stimulus magnitude (stimulation energy) in order to maintain a comfortable and effective stimulation therapy. Because the changes in impedance associated with the electrode-tissue interface can indicate obstruction of current flow and positional lead displacement, lead impedance can indicate the quantity of electrical stimulation energy that should be delivered to the target neural tissue to provide corrective adjustment. Hence, a change in impedance or morphology of an impedance curve may be used in a feedback loop to indicate that the stimulation energy needs to be adjusted and the system can effectively auto correct the magnitude of stimulation energy to maintain a desired therapeutic effect.
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Citations
29 Claims
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1. A method of neural stimulation using a neurostimulator, the method comprising:
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correlating impedance changes with predicted stimulation energy adjustments; initially storing the correlated measured impedance changes and predicted stimulation energy adjustments in a look-up table; measuring a change in impedance indicative of variations in the coupling efficiency between stimulation energy output from the neurostimulator and neural tissue; subsequently analyzing the stored correlated measured impedance changes and predicted stimulation energy adjustments to determine the predicted stimulation energy adjustment correlated to the measured impedance change; and automatically adjusting the stimulation energy output from the neurostimulator accordance with the determined stimulation energy adjustment to compensate for the variations in the coupling efficiency by maintaining the stimulation energy delivered to the neural tissue at a set level. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of neural stimulation using a neurostimulator, the method comprising:
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correlating impedance changes with predicted stimulation energy adjustments; measuring a change in impedance indicative of variations in the coupling efficiency between stimulation energy output from the neurostimulator and neural tissue, wherein the change in impedance is measured by taking at least two impedance samples over time and comparing the at least two impedance measurements to each other; cross-referencing the measured impedance change with the correlated impedance changes to determine the adjustment of the stimulation energy output from the neurostimulator; and automatically adjusting the stimulation energy output from the neurostimulator in accordance with the determined adjustment of the stimulation energy output in order to compensate for the variations in the coupling efficiency. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of neural stimulation using a neurostimulator, the method comprising:
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correlating impedance changes with predicted stimulation energy adjustments by having a patient implanted with the neurostimulator make positional movements to induce changes in measured impedance and recording impedance measurements as a function of the positional movements; measuring a change in impedance indicative of variations in the coupling efficiency between stimulation energy output from the neurostimulator and neural tissue; and automatically adjusting the stimulation energy output from the neurostimulator based on the predicted stimulation energy adjustments and the measured impedance change to compensate for the variations in the coupling efficiency by maintaining the stimulation energy delivered to the neural tissue at a set level. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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26. A method of neural stimulation using a neurostimulator, the method comprising:
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correlating characteristic impedance waveform morphologies with predicted stimulation energy adjustments; measuring a characteristic impedance waveform morphology indicative of variations in the coupling efficiency between stimulation energy output from the neurostimulator and neural tissue; and automatically adjusting the stimulation energy output from the neurostimulator based on the predicted stimulation energy adjustments and the measured characteristic impedance waveform morphology to compensate for the variations in the coupling efficiency by maintaining the stimulation energy delivered to the neural tissue at a set level. - View Dependent Claims (27, 28, 29)
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Specification