Stimulation signal generator for an implantable device
First Claim
1. A neurostimulation system for treating a disorder in a brain of a patient, comprising:
- a stimulation subsystem adapted to apply an electrical stimulation signal to neural tissue of the patient; and
a plurality of electrodes including a first electrode and a second electrode, each in electrical communication with the stimulation subsystem;
wherein the stimulation subsystem includes a stimulation signal generator adapted to deliver a controlled electrical current from a stimulation signal input through a stimulation load between the first electrode and the second electrode; and
wherein the stimulation signal generator includes a programmable current digital-to-analog converter in series with the stimulation load; and
wherein the programmable current digital-to-analog converter comprises a programmable resistor in series with the stimulation load, a reference voltage source providing a reference voltage, and a current controller adapted to match a voltage at an upstream end of the programmable resistor to the reference voltage.
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Accused Products
Abstract
An implantable multimodal neurostimulator having improved efficacy in treating epilepsy and other neurological disorders and processes of using that neurostimulator are described herein. The neurostimulator itself generally has two modes of electrical stimulation. The first involves delivering a non-responsive electrical stimulation signal that is applied to the central nervous system to reduce the likelihood of a seizure or other undesirable neurological even from occurring. Various waveform morphologies are described for non-responsive stimulation signals. A second mode involves delivering a responsive electrical stimulation signal when epileptiform waveforms are impending or extant. The responsive electrical stimulation signal is intended to terminate epileptiform activity, e.g., to desynchronize abnormally synchronous brain electrical activity.
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Citations
55 Claims
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1. A neurostimulation system for treating a disorder in a brain of a patient, comprising:
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a stimulation subsystem adapted to apply an electrical stimulation signal to neural tissue of the patient; and
a plurality of electrodes including a first electrode and a second electrode, each in electrical communication with the stimulation subsystem;
wherein the stimulation subsystem includes a stimulation signal generator adapted to deliver a controlled electrical current from a stimulation signal input through a stimulation load between the first electrode and the second electrode; and
wherein the stimulation signal generator includes a programmable current digital-to-analog converter in series with the stimulation load; and
wherein the programmable current digital-to-analog converter comprises a programmable resistor in series with the stimulation load, a reference voltage source providing a reference voltage, and a current controller adapted to match a voltage at an upstream end of the programmable resistor to the reference voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A neurostimulation system for treating a disorder in a brain of a patient, comprising:
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a stimulation subsystem adapted to apply a therapeutic electrical stimulation signal to the brain of the patient; and
a plurality of electrodes including a first electrode and a second electrode, each in electrical communication with the stimulation subsystem;
wherein the stimulation subsystem includes a stimulation signal generator adapted to deliver a controlled electrical current through a stimulation load between the first electrode and the second electrode; and
wherein the stimulation signal generator includes a programmable H-bridge circuit adapted to control the direction of current flow between the first electrode and the second electrode and a programmable current digital-to-analog converter in series with the stimulation load, the programmable current digital-to-analog converter including a programmable resistor and a current controller adapted to match a voltage at an upstream end of the programmable resistor to a reference voltage. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A method for treating a disorder in a brain of a patient, the method comprising the steps of:
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generating a stimulation voltage;
configuring a switching matrix to select a first electrode and a second electrode from a plurality of electrodes;
connecting the stimulation voltage source to the first electrode and a programmable digital-to-analog current sink to the second electrode, thereby delivering a stimulation signal to the brain of the patient; and
controlling the programmable digital-to-analog current sink with a stimulation waveform to regulate an electrical current present in the stimulation signal. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55)
connecting the stimulation voltage source to the second electrode and the programmable digital-to-analog current sink to the first electrode, thereby delivering a charge balancing signal to the brain of the patient; and
controlling the programmable digital-to-analog current sink with a charge balancing waveform to regulate the electrical current present in the charge balancing signal.
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47. The method for treating a disorder of claim 46, wherein the stimulation waveform is substantially identical to the charge balancing waveform.
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48. The method for treating a disorder of claim 45, wherein the charge balancing step comprises the steps of:
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calculating an accumulated charge in the stimulation waveform; and
controlling the programmable digital-to-analog current sink to achieve an accumulated charge near zero.
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49. The method for treating a disorder of claim 48, wherein the charge balancing step further comprises the step of controlling the programmable digital-to-analog current sink to ensure the accumulated charge does not exceed a threshold.
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50. The method for treating a disorder of claim 39, further comprising the step of determining whether the stimulation voltage is sufficient to enable delivery of a desired electrical current through a load defined by the brain of the patient between the first electrode and the second electrode.
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51. The method for treating a disorder of claim 50, further comprising the step of generating a current tilt signal if the stimulation voltage is insufficient.
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52. The method for treating a disorder of claim 51, further comprising the step of performing an action in response to the current tilt signal.
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53. The method for treating a disorder of claim 39, further comprising the step of determining whether a leakage current from a leakage electrode in the brain of the patient exceeds a threshold.
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54. The method for treating a disorder of claim 53, further comprising the step of generating a leakage current signal if the leakage current exceeds the threshold.
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55. The method for treating a disorder of claim 54, further comprising the step of performing an action in response to the leakage current signal.
Specification