Neurostimulation system and method for automatically adjusting stimulation and reducing energy requirements using evoked action potential

Abstract

A neurostimulation system comprising stimulation output circuitry configured for delivering stimulation pulses to target tissue in accordance with a set of stimulation parameters. The neurostimulation system comprises monitoring circuitry configured for continuously measuring action potentials evoked in the target tissue in response to the delivery of the stimulation pulses to the target tissue, memory configured for storing a characteristic of a reference evoked action potential, and at least one processor configured for initiating an automatic mode, in which a characteristic of the measured evoked action potentials is compared to the corresponding characteristic of the reference evoked action potential, and one or more stimulation parameter values in the set of stimulation parameters are adjusted to decrease or increase the energy level of the stimulation pulses, thereby evoking action potentials in the target tissue having substantially the same corresponding characteristic as the reference evoked action potential.

1 . (canceled) 
     
     
         2 . A method performed using a Spinal Cord Stimulation (SCS) system configured to deliver SCS for a pain therapy; the method comprising:
 delivering at least two levels of neurostimulation, including a first level and a second level, to target tissue in or near a spine according to a programmed therapy schedule, wherein the first and the second levels of neurostimulation correspond to a first and a second templates, respectively, wherein the first and second templates are stored in memory, the first and the second of the at least two levels of neurostimulation correspond to first and second sets of stimulation parameter values, respectively;   verifying, throughout a course of the pain therapy, whether the neurostimulation delivered using the stimulation parameter values for the first and second sets of stimulation parameters is effective for the pain therapy by monitoring whether the stimulation is causing evoked action potentials, wherein the verifying includes:
 determining waveform characteristic values of action potentials throughout the course of the therapy, including determining a first set of waveform characteristic values corresponding to times when the first level of neurostimulation is delivered and determining a second set of waveform characteristic values corresponding to times when the second level of neurostimulation is delivered; and 
 comparing the first set and the second set of waveform characteristic values to waveform characteristic values in the first and second templates, respectively; and 
   maintaining an efficacious therapeutic effect throughout the course of therapy, including:
 continuing to use the first set of stimulation parameter values to deliver the first level of neurostimulation when the first set of waveform characteristic values similarly correspond to the waveform characteristic values in the first template, and adjusting the first set of stimulation values when the first set of waveform characteristic values do not similarly correspond to the waveform characteristic values in the first template; and 
 continuing to use the second set of stimulation parameter values to deliver the second level of neurostimulation when the second set of waveform characteristic values similarly correspond to the waveform characteristic values in the second template, and adjusting the second set of stimulation values when the second set of waveform characteristic values do not similarly correspond to the waveform characteristic values in the second template. 
   
     
     
         3 . The method of  claim 2 , wherein the adjusting the first set of the stimulation values or the second set of stimulation values includes adjusting at least one of a pulse amplitude, a pulse width, or a pulse rate. 
     
     
         4 . The method of  claim 2 , wherein the adjusting the first set of the stimulation values or the second set of stimulation values includes adjusting at least one of a duty cycle or a burst rate. 
     
     
         5 . The method of  claim 2 , wherein the adjusting the first set of the stimulation values or the second set of stimulation values includes adjusting an electrode combination. 
     
     
         6 . The method of  claim 2 , wherein the waveform characteristic values include values for at least one of peak delay, width, amplitude, or waveform morphology. 
     
     
         7 . The method of  claim 2 , wherein evoked action potentials include an evoked compound action potential or an evoked compound muscle action potential. 
     
     
         8 . The method of  claim 2 , wherein evoked action potentials include at least one of therapeutic evoked action potentials or side-effect evoked action potentials. 
     
     
         9 . The method of  claim 2 , wherein first or second sets of waveform characteristic values do not similarly correspond to the waveform characteristic values in the first or second templates, respectively, when at least one of the first or second sets of waveform characteristic values is different from the waveform characteristic values in the first or second sets of waveform characteristic values. 
     
     
         10 . The method of  claim 2 , wherein first or second sets of waveform characteristic values do not similarly correspond to the waveform characteristic values in the first or second templates, respectively, when at least one of the first or second sets of waveform characteristic values is different from the waveform characteristic values in the first or second sets of waveform characteristic values by more than a tolerance threshold. 
     
     
         11 . The method of  claim 2 , wherein first or second sets of waveform characteristic values do not similarly correspond to the waveform characteristic values in the first or second templates, respectively, when at least one of the first or second sets of waveform characteristic values is different from the waveform characteristic values in the first or second sets of waveform characteristic values for more than a threshold time period. 
     
     
         12 . The method of  claim 2 , wherein first or second sets of waveform characteristic values do not similarly correspond to the waveform characteristic values in the first or second templates, respectively, when at least one of the first or second sets of waveform characteristic values is different from the waveform characteristic values in the first or second sets of waveform characteristic values for more than a threshold number of measurements. 
     
     
         13 . The method of  claim 2 , wherein the adjusting the first set or the second set of stimulation values is based on a patient's movement. 
     
     
         14 . The method of  claim 2 , wherein the adjusting the first set or the second set of stimulation values is based on a patient's temperature. 
     
     
         15 . The method of  claim 2 , wherein the adjusting the first set or the second set of stimulation values is based on a patient's blood flow. 
     
     
         16 . The method of  claim 2 , wherein the adjusting the first set or the second set of stimulation values is based on an electrocortigram or, an electroencephalogram. 
     
     
         17 . The method of  claim 2 , wherein the adjusting the first set or the second set of stimulation values is based on a tissue or transcutaneous oxygen tension. 
     
     
         18 . The method of  claim 2 , wherein the adjusting the first set or the second set of stimulation values is based on a chemical species concentration. 
     
     
         19 . The method of  claim 2 , wherein the adjusting the first set or the second set of stimulation values is based on a glucose concentration. 
     
     
         20 . The method of  claim 2 , wherein the adjusting the first set or the second set of stimulation values is based on an impedance measurement 
     
     
         21 . The method of  claim 2 , wherein the adjusting the first set or the second set of stimulation values is based on whether the patient is asleep or awake.