Neural stimulation system providing auto adjustment of stimulus output as a function of sensed coupling efficiency
First Claim
1. A method of neural stimulation comprising:
- measuring the coupling efficiency of an electrical stimulation current applied to neural tissue; and
automatically adjusting the magnitude of subsequent stimulating current pulses in order to compensate for variations in the measured coupling efficiency.
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Accused Products
Abstract
A neural stimulation system automatically corrects or adjusts the stimulus magnitude in order to maintain a comfortable and effective stimulation therapy. Auto correction of the stimulus magnitude is linked to the measurement of coupling efficiency. Because the events that lead to the necessity of an output amplitude change are all associated with how much electrical energy is coupled to the neural tissue, and because there are several physiologic parameters that reflect in some measure how much energy is actually coupled to the tissue, the measurement of the one or more of such physiologic parameters is used as an indicator of the electrode'"'"'s effectiveness in providing therapeutic stimulation. The physiologic parameters that may be measured, and used by the invention as a measure of coupling efficiency, include: action potential(s); the optical transmissive and/or reflective properties of the tissue and fluids surrounding or adjacent the target neural tissue; the chemistry of the fluids and tissue near the electrodes, e.g., in the epidural space; or the changes in pressure that occur near the electrodes, e.g., in the epidural space. The relative change in the measured physiologic parameter is used as an indicator of the obstruction to current flow between the electrodes and the neural tissue. Such knowledge with respect to time thus permits the neural stimulation system to effectively auto-correct the output amplitude, thereby minimizing the occurrence of over-stimulation or under-stimulation.
158 Citations
17 Claims
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1. A method of neural stimulation comprising:
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measuring the coupling efficiency of an electrical stimulation current applied to neural tissue; and
automatically adjusting the magnitude of subsequent stimulating current pulses in order to compensate for variations in the measured coupling efficiency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A neural stimulation system comprising:
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a plurality of electrodes;
a pulse generator connected to the plurality of electrodes, wherein the pulse generator provides stimulation current pulses to selected electrodes of the plurality of electrodes at a prescribed magnitude;
means for measuring a physiologic parameter indicative of coupling efficiency;
means for determining a change in the physiologic parameter over time; and
auto correction means for adjusting the magnitude of the stimulation current pulse as a function of the amount of change detected in the physiologic parameter over time. - View Dependent Claims (11, 12, 13)
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14. An implantable spinal cord stimulation system comprising:
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means for measuring the coupling efficiency of an electrical stimulation current applied to neural tissue in or near the epidural space; and
means for automatically adjusting the magnitude of subsequent stimulating current pulses in order to compensate for variations in the measured coupling efficiency. - View Dependent Claims (15, 16, 17)
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Specification