Systems and methods for monitoring neurostimulation dosing

Abstract

Various implantable device embodiments may comprise a neural stimulator configured to deliver a neurostimulation therapy with stimulation ON times and stimulation OFF times where a dose of the neurostimulation therapy is provided by a number of neurostimulation pulses over a period of time. The neural stimulator may be configured to monitor the dose of the delivered neurostimulation therapy against dosing parameters. The neural stimulator may be configured to declare a fault if the monitored dose does not favorably compare to a desired dose for the neurostimulation therapy, or may be configured to record data for the monitored dose of the delivered neurostimulation therapy, or may be configured to both record data for the monitored dose of the delivered neurostimulation therapy and declare a fault if the monitored dose does not favorably compare to a desired dose for the neurostimulation therapy.

1 . (canceled) 
     
     
         2 . A method for operating an implantable medical device (IMD), comprising:
 delivering a neurostimulation therapy using the IMD, wherein a prescribed dose of the neurostimulation therapy corresponds to a lower charge limit over a period of time;   monitoring a delivered dose of the neurostimulation therapy with respect to the prescribed dose using the IMD to determine whether the delivered dose is delivering an amount of charge at least equal to the lower charge limit over the period of time; and   performing an action using the IMD, including:
 declaring a fault if the monitored delivered dose does not deliver the amount of charge at least equal to the lower charge limit; or 
 recording data for the monitored delivered dose of the neurostimulation therapy. 
   
     
     
         3 . The method of  claim 2 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes monitoring charge depletion for a time period and comparing the monitored charge depletion against a limit corresponding to the prescribed dose. 
     
     
         4 . The method of  claim 2 , wherein monitoring the delivered dose of the delivered neurostimulation therapy with respect to the prescribed dose includes monitoring charge depletion for time periods, wherein for each time period monitoring includes determining a rolling average of charge depletion, and comparing the rolling average of charge depletion against a limit corresponding to the prescribed dose. 
     
     
         5 . The method of  claim 2 , wherein performing the action includes declaring the fault, and either stopping the neurostimulation therapy in response to the fault or altering the neurostimulation therapy in response to the fault. 
     
     
         6 . The method of  claim 2 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes monitoring charge depletion from a power supply used to deliver the neurostimulation therapy by performing at least one of:
 estimating the amount of charge delivered to stimulated tissue using the monitored charge depletion from the power supply;   using a coulomb counter to monitor charge depletion from the power supply;   using a consumption monitor to monitor current consumption from the power supply; or   
       estimating a consumed charge from the power supply over the time period using a value of charge per maintenance event and a number of maintenance events to keep the power supply at a programmed level. 
     
     
         7 . The method of  claim 2 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes monitoring charge or current flowing through a path to the stimulated tissue. 
     
     
         8 . The method of  claim 7 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes using a coulomb counter to monitor charge in the path to the stimulated tissue. 
     
     
         9 . The method of  claim 7 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes using a consumption monitor to monitor current in the path to the stimulated tissue. 
     
     
         10 . The method of  claim 7 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes estimating the charge or the current flowing through the path to the stimulated tissue over the time period using a value of charge per maintenance event and a number of maintenance events to keep a power supply at a programmed level. 
     
     
         11 . The method of  claim 2 , wherein delivering the neurostimulation therapy includes delivering neurostimulation to a neural target selected from the group of neural targets consisting of: a peripheral neural target, a spinal neural target, a motor neural target, and an autonomic neural target. 
     
     
         12 . A method for operating an implantable medical device (IMD), comprising:
 delivering a neurostimulation therapy using the IMD, wherein a prescribed dose of the neurostimulation therapy corresponds to an amount of charge delivered to the stimulated tissue over a period of time;   monitoring delivered doses of the neurostimulation therapy with respect to the prescribed dose; and   using the IMD to record data corresponding to the monitored delivered doses.   
     
     
         13 . The method of  claim 12 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes monitoring charge depletion for a time period and comparing the monitored charge depletion against a limit corresponding to the prescribed dose. 
     
     
         14 . The method of  claim 12 , wherein monitoring the delivered dose of the delivered neurostimulation therapy with respect to the prescribed dose includes monitoring charge depletion for time periods, wherein for each time period monitoring includes determining a rolling average of charge depletion, and comparing the rolling average of charge depletion against a limit corresponding to the prescribed dose. 
     
     
         15 . The method of  claim 12 , wherein performing the action includes declaring the fault, and either stopping the neurostimulation therapy in response to the fault or altering the neurostimulation therapy in response to the fault. 
     
     
         16 . The method of  claim 12 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes monitoring charge depletion from a power supply used to deliver the neurostimulation therapy by performing at least one of:
 estimating the amount of charge delivered to stimulated tissue using the monitored charge depletion from the power supply;   using a coulomb counter to monitor charge depletion from the power supply;   using a consumption monitor to monitor current consumption from the power supply; or   
       estimating a consumed charge from the power supply over the time period using a value of charge per maintenance event and a number of maintenance events to keep the power supply at a programmed level. 
     
     
         17 . The method of  claim 12 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes monitoring charge or current flowing through a path to the stimulated tissue. 
     
     
         18 . The method of  claim 17 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes using a coulomb counter to monitor charge in the path to the stimulated tissue. 
     
     
         19 . The method of  claim 17 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes using a consumption monitor to monitor current in the path to the stimulated tissue. 
     
     
         20 . The method of  claim 17 , wherein monitoring the delivered dose of the neurostimulation therapy with respect to the prescribed dose includes estimating the charge or the current flowing through the path to the stimulated tissue over the time period using a value of charge per maintenance event and a number of maintenance events to keep a power supply at a programmed level. 
     
     
         21 . The method of  claim 12 , wherein delivering the neurostimulation therapy includes delivering neurostimulation to a neural target selected from the group of neural targets consisting of: a peripheral neural target, a spinal neural target, a motor neural target, and an autonomic neural target.