System and method for closed-loop neural stimulation

Abstract

Various device embodiments comprise a pulse generator, a signal processing module and a controller. The pulse generator is adapted to provide a neural stimulation signal to be applied at a neural simulation site within an autonomic nervous system (ANS). The signal processing module is adapted to receive and process sensed neural traffic at a neural sensing site within the ANS. The controller is connected to the pulse generator and adapted to provide a neural stimulation control signal to the pulse generator to generate the neural stimulation signal, and to the signal processing module to receive a feedback control signal indicative of the sensed neural traffic. The controller is adapted to adjust the neural stimulation control signal to adjust at least one parameter of the neural stimulation signal to converge on desired sensed neural traffic at the neural sensing site. Other aspects and embodiments are provided herein.

1 . (canceled) 
     
     
         2 . A device for delivering a closed-loop neural stimulation therapy to a desired neural target in an autonomic nervous system (ANS) to converge on a desired neural response, wherein the ANS includes a reflex circuit, the device comprising:
 a pulse generator adapted to provide a neural stimulation signal to stimulate the desired neural target for the neural stimulation therapy, wherein stimulating the desired neural target affects neural traffic at a neural sensing site through the reflex circuit of the ANS;   a signal processing module adapted to receive and process a nerve traffic signal representative of sensed nerve activity at the neural sensing site, wherein the signal processing module is adapted to receive and process the nerve traffic signal into a signal indicative of a detected reflex neural response to stimulating the neural target; and   a controller connected to the pulse generator and the signal processing module, wherein the controller is adapted to adjust at least one stimulation parameter of the neural stimulation signal based on the detected reflex neural response to cause the detected reflex neural response to converge on the desired neural response to the neural stimulation signal, wherein the controller includes:
 a programmed target for the signal indicative of the detected reflex response; 
 a feedback comparator configured to receive the signal indicative of the detected reflex response from the signal processing module, compare the signal indicative of the detected reflex response to the programmed target, and generate a feedback signal for use in controlling the closed-loop neural stimulation therapy; 
 an associator adapted to associate a stimulation event at the neural target to sensed nerve activity at the neural sensing site to verify a causal relationship between the stimulation event and the sensed nerve activity, and adapted to provide an association result indicating when the sensed nerve activity has a causal relationship with the stimulation event through the reflex circuit of the ANS; and 
 a neural controller adapted to receive the association result to confirm that the sensed nerve activity is the detected reflex response, adapted to receive the feedback signal, and adapted to generate a stimulation control signal using the feedback signal to adjust the at least one stimulation parameter to cause the detected reflex neural response to converge on the desired neural response. 
   
     
     
         3 . The device of  claim 2 , wherein the controller is configured to account for a reflex circuit time from the stimulation event to a time when the stimulated desired neural target affects neural traffic at the neural sensing site through the reflex circuit of the ANS. 
     
     
         4 . The device of  claim 2 , wherein the associator is adapted to use averaging to associate the sensed activity to the stimulation event. 
     
     
         5 . The device of  claim 2 , wherein the associator is adapted to use temporal correlation to associate the sensed activity to the stimulation event. 
     
     
         6 . The device of  claim 2 , wherein the neural simulation site is at the neural sensing site. 
     
     
         7 . The device of  claim 2 , wherein the parasympathetic neural stimulation site is a different site than the parasympathetic neural sensing site. 
     
     
         8 . The device of  claim 2 , wherein the desired neural target is a parasympathetic neural stimulation site and the neural sensing site is a sympathetic neural sensing site, the controller being adapted to adjust the at least one parameter of the neural stimulation signal to converge on the desired neural response at the sympathetic neural sensing site by reducing the stimulation if the nerve traffic signal is too low and increasing the stimulation if the nerve traffic signal is too high. 
     
     
         9 . The device of  claim 2 , wherein the desired neural target is a sympathetic neural stimulation site and the neural sensing site is a parasympathetic neural sensing site, the neural controller being adapted to adjust the at least one parameter of the neural stimulation signal to converge on the desired sensed neural traffic at the parasympathetic neural sensing site by reducing the stimulation if the nerve traffic signal is too low and increasing the stimulation if the nerve traffic signal is too high. 
     
     
         10 . The device of  claim 9 , wherein the desired neural target is a cardiac sympathetic nerve branch, and the neural sensing site is a baroreceptor site. 
     
     
         11 . The device of  claim 2 , wherein the neural controller is configured to receive a dynamic input control signal to adjust the target. 
     
     
         12 . The device of  claim 2 , wherein the neural controller is configured to receive a gain input control signal to increment and decrement a gain for an intensity of the neural stimulation based on the feedback control signal and wherein the neural controller is configured to receive a dynamic input control signal to adjust the gain. 
     
     
         13 . The device of  claim 2 , wherein the neural stimulation site includes at least one of a vagus nerve and a cardiac fat pad, and the neural sensing site includes a baroreceptor site. 
     
     
         14 . The device of  claim 2 , wherein the neural stimulation site includes a first site on a vagus nerve, and the neural sensing site includes a second site on the vagus nerve. 
     
     
         15 . The device of  claim 2 , wherein one of the desired neural target and the neural sensing site is an efferent site and the other is an afferent site. 
     
     
         16 . The device of  claim 2 , wherein both the desired neural target and the neural sensing site are afferent sites on the vagus nerve, or both the desired neural target and the neural sensing site are efferent sites on the vagus nerve. 
     
     
         17 . The device of  claim 2 , wherein both the neural stimulation site and the neural sensing site include a cardiac sympathetic nerve branch. 
     
     
         18 . The device of  claim 2 , wherein the device is configured to perform an iterative protocol to determine effects of one or more neural stimulation parameter changes. 
     
     
         19 . The device of  claim 2 , wherein the programmed target for the signal indicative of the detected reflex response includes a target operating range of evoked response magnitude. 
     
     
         20 . The device of  claim 2 , wherein the programmed target for the signal indicative of the detected reflex response includes a target operating range of an evoked response pattern, wherein the evoked response pattern includes a one or more of a delay, a duration or a frequency of the sensed nerve activity. 
     
     
         21 . A device, comprising:
 a pulse generator adapted to provide a neural stimulation signal to be applied at a neural simulation site within an autonomic nervous system (ANS);   a signal processing module adapted to receive and process sensed neural traffic at a neural sensing site within the ANS, wherein the sensed neural traffic includes an evoked response to the neural stimulation signal applied at the neural stimulation site;   a controller configured to provide closed-loop control of the pulse generator, wherein the controller is connected to the pulse generator and adapted to provide a neural stimulation control signal to the pulse generator to generate the neural stimulation signal and connected to the signal processing module to receive a feedback control signal indicative of the evoked nerve traffic response to the neural stimulation signal, wherein the controller is configured to provide the closed-loop control by adjusting the neural stimulation control signal to adjust at least one parameter of the neural stimulation signal to converge on a desired evoked nerve traffic response target,   wherein the controller is configured to receive a gain control input to control a desired increment or decrement in neural stimulation intensity to converge on the desired evoked nerve traffic response target.