Stimulation apparatus
A medical apparatus for a patient comprises an external system and an implantable system. The external system is configured to transmit one or more transmission signals, each transmission signal comprising at least power or data. The implantable system is configured to receive the one or more transmission signals from the external system, and to deliver stimulation energy to the patient. Methods of delivering stimulation energy are also provided.
1 . A system for delivering stimulation energy to a patient, comprising:
an implantable device comprising:
at least one sensor for measuring electrically-evoked compound action potential (ECAP) signals; and
at least one stimulation element configured to deliver the stimulation energy to tissue, wherein the system is configured to produce an artifact-compensated ECAP signal by:
recording an artifact via an amplifier; and
subsequently recording an ECAP signal via the amplifier while applying an inverse of the recorded artifact to an input of the amplifier.
2 . The system of claim 1 , wherein the amplifier is configured to record the ECAP signal with high gain.
3 . The system of claim 1 , wherein the amplifier is configured to record the artifact with low gain.
4 . The system of claim 3 , wherein the amplifier operates in a linear range.
5 . The system of claim 1 , wherein applying an inverse of the recorded artifact is a first artifact cancellation technique, and wherein the system is further configured to produce the artifact-compensated ECAP signal by applying a second artifact cancellation technique.
6 . The system of claim 1 further comprising an analog to digital converter configured to perform a plurality of captures of one or both of the artifact and the ECAP signal, wherein the implantable device is configured to average the plurality of captures of one or both of the artifact and the ECAP signal to reduce noise.
7 . The system of claim 1 , wherein the stimulation energy delivered by the at least one implantable stimulation element comprises a tonic stimulation waveform that is provided at a high amplitude for a first time period, and wherein the tonic stimulation waveform is provided at a decreased amplitude during a subsequent second time period.
8 . The system of claim 7 , wherein the decreased amplitude comprises a sub-threshold amplitude or zero amplitude.
9 . The system of claim 7 , wherein the system is configured to deliver the decreased amplitude in an adaptive manner.
10 . The system of claim 9 , wherein the system is configured to deliver the decreased amplitude based on patient feedback regarding pain relief.
11 . The system of claim 7 , wherein the decreased amplitude is delivered over a pre-defined duration.
12 . The system of claim 1 , wherein the stimulation energy delivered by the at least one implantable stimulation element comprises a high frequency tonic stimulation waveform combined with a low frequency tonic stimulation waveform.
13 . The system of claim 1 , wherein the stimulation energy delivered by the at least one implantable stimulation element comprises a first plurality of pulses separated by an inter-pulse gap and configured to create a similar physiologic effect as a single pulse having a duration that is about equal to a duration of the first plurality of pulses.
14 . The system of claim 13 , wherein the system further comprises a user interface configured to allow an operator to enter a pulse density percentage, and wherein the stimulation energy is delivered based on the entered pulse density percentage.
15 . The system of claim 14 , wherein the system is configured to calculate a pulse width and the inter-pulse gap of the first plurality of pulses based on the pulse density percentage entered and a pulse width of a first pulse to stimulate.
16 . The system of claim 1 , wherein the at least one stimulation element comprises a set of stimulation elements that are configured to deliver the stimulation energy to a plurality of anatomical areas.
17 . The system of claim 16 , wherein the plurality of anatomical areas comprises at least four anatomical areas.
18 . The system of claim 13 , wherein a pulse width of each of the first plurality of pulses is more than 300 μs, and the inter-pulse gap is no more than 100 μs.
19 . The system of claim 1 , wherein the artifact comprises a signal tail of a first stimulation pulse, and wherein the signal tail results from an RC discharge time of capacitances in a path of the first stimulation pulse.
20 . The system of claim 19 , wherein the at least one stimulation element comprises an electrode, and wherein the path of the first stimulation pulse comprises an electrode-tissue interface.
21 . The system of claim 1 , wherein the recorded artifact and the inverse of the recorded artifact sum to zero.
22 . The system of claim 1 , wherein the system is configured to use the artifact-compensated ECAP signal to determine a stimulation paradigm for the patient, and to deliver the stimulation energy to the patient based on the determined stimulation paradigm.
23 . The system of claim 1 further comprising an external device configured to transmit one or both of power and data to the implantable device.
24 . The system of claim 1 further comprising a memory configured to store the recorded artifact, wherein the system is further configured to invert the stored artifact.
25 . The system of claim 1 further comprising a digital-to-analog converter (DAC) configured to convert the inverse of the recorded artifact to an analog signal, wherein the analog signal is applied to the input of the amplifier while recording the ECAP signal.
26 . The system of claim 1 , wherein the amplifier comprises a variable-gain amplifier, and wherein the system is configured to record the artifact with the amplifier at a first gain setting and to record the ECAP signal with the amplifier at a second gain setting higher than the first gain setting.
27 . The system of claim 1 , wherein the input of the amplifier comprises an offset adjustment input.