Microburst electrical stimulation of cranial nerves for the treatment of medical conditions

Abstract

Disclosed herein are methods, systems, and apparatus for treating a medical condition in a patient using an implantable medical device by applying an electrical signal characterized by having a number of pulses per microburst, an interpulse interval, a microburst duration, and an interburst period to a portion of a cranial nerve of said patient, wherein at least one of the number of pulses per microburst, the interpulse interval, the microburst duration, or the interburst period is selected to enhance cranial nerve evoked potentials.

1 . A method of treating a medical condition in a patient using an implantable medical device, comprising: applying to a cranial nerve a first electrical signal including at least one microburst of a plurality of pulses during a first time period to treat the medical condition, the first time period being a time period during which there is no indication that an acute condition has occurred; and applying a second electrical signal to the cranial nerve to treat the medical condition in response to an indication of an acute event associated with the medical condition for treating the acute event, the second electrical signal including at least one burst of a second plurality of pulses during a second time period that is a non-microburst, wherein the first time period occurs prior to the second time period;
 wherein applying the first electrical signal further comprises applying the microburst signal in a predetermined timing pattern; 
 wherein applying the second electrical signal in an acute therapy mode is triggered by the indication of the acute event where the acute therapy mode is implemented in a course that has a predetermined duration, the predetermined duration being independent of a change in an initiation signal for the second electrical signal. 
 
     
     
         2 . The method of  claim 1 , wherein applying the second electrical signal in response to the indication that the acute event has occurred further comprises applying the second electrical signal based on at least one of an indication that an epileptic seizure has occurred, an indication that the epileptic seizure is substantially imminent, or than an imminent occurrence of the epileptic seizure is highly probable, and wherein applying the first electrical signal further comprises applying the first electrical signal to provide a chronic treatment for an epilepsy condition. 
     
     
         3 . The method of  claim 1 , further comprising applying a seizure detection algorithm based on at least one sensed body parameter selected from a heart rate parameter, a temperature, an EEG signal, a breathing rate, and an eye parameter, wherein a first time period determination based on the seizure detection algorithm provides no indication that the patient has entered an unstable brain state. 
     
     
         4 . The method of  claim 1 , further comprising applying a seizure detection algorithm to at least one sensed body parameter based on at least one of a heart rate parameter, a temperature, an EEG signal, a breathing rate, and an eye parameter, wherein applying the second electrical signal is based on a determination by the seizure detection algorithm indicating that the patient has entered into an unstable brain state. 
     
     
         5 . The method of  claim 1 , wherein applying the microburst signal substantially synchronous to the heartbeat of the patient further comprises the microburst being delivered in one of a predetermined time period or a derived time period following a R-wave of the heartbeat of the patient. 
     
     
         6 . The method of  claim 1 , wherein applying the first electrical signal further comprises applying the first electrical signal in a pulse range from about 2 pulses to about 10 pulses and having a microburst duration less than about 100 msec. 
     
     
         7 . The method of  claim 1 , wherein applying the first electrical signal further comprises applying the first electrical signal in a pulse range from about 2 pulses to about 6 pulses and having a microburst duration in a duration range from about 20 msec to about 80 msec. 
     
     
         8 . The method of  claim 1 , wherein applying the first electrical signal and the second electrical signal to the cranial nerve further comprises generating electrical signals with an electrical signal generator and applying the first electrical signal and the second electrical signal to an electrode. 
     
     
         9 . The method of  claim 1 , wherein applying the second electrical signal is characterized by at least about 100 pulses per burst and a burst duration of at least about 2 sec. 
     
     
         10 . The method of  claim 1 , wherein applying the first electrical signal to the cranial nerve further comprises applying the first electrical signal to at least one of a left vagus nerve or a right vagus nerve. 
     
     
         11 . An implantable medical device comprising one or more processors configured to:
 apply to a cranial nerve via one or more electrodes a first electrical signal during a first time period to treat a medical condition;
 wherein the first electrical signal includes at least one microburst; and 
 wherein during the first time period there is no indication that an acute condition has occurred; and 
   apply to the cranial nerve via the one or more electrodes a second electrical signal during a second time period to treat the medical condition in response to an indication of an acute event associated with the medical condition;
 wherein the second electrical signal includes at least one non-microburst; 
 wherein the first time period occurs prior to the second time period; and 
 a patient parameter monitoring device; 
 wherein the one or more processors is configured to apply via the one or more electrodes the first electrical signal in a predetermined timing pattern; 
 wherein applying the second electrical signal in an acute therapy mode is triggered by the indication of the acute event where the acute therapy mode is implemented in a course that has a predetermined duration, the predetermined duration being independent of a change in an initiation signal for the second electrical signal. 
   
     
     
         12 . The implantable medical device of  claim 11 , further comprising a seizure detection device, the seizure detection device includes a seizure detection algorithm which is configured to detect a potential seizure based on at least one sensed body parameter selected from a heart rate parameter, a temperature, an EEG signal, a breathing rate, and an eye parameter. 
     
     
         13 . The implantable medical device of  claim 12 , wherein the one or more processors are configured to apply via the one or more electrodes the second electrical signal based on at least one of an indication that an epileptic seizure has occurred, an indication that the epileptic seizure is imminent, or an indication that the epileptic seizure is probable. 
     
     
         14 . The implantable medical device of  claim 11 , further comprising a medical condition detection device and wherein the one or more processors are configured to apply via the one or more electrodes the second electrical signal based on at least one of an indication that the medical condition has occurred, an indication that the medical condition is imminent, or an indication that the medical condition is probable. 
     
     
         15 . A system for treating a medical condition, the system configured to:
 apply to a cranial nerve a first electrical signal during a first time period;
 wherein the first electrical signal includes at least one microburst; and 
 wherein during the first time period there is no indication that an acute condition has occurred; 
   apply to the cranial nerve a second electrical signal during a second time period to treat the medical condition in response to an indication of an acute event associated with the medical condition;   wherein the second electrical signal includes at least one non-microburst;   wherein the first time period occurs prior to the second time period; and   apply the first electrical signal in a predetermined timing pattern;   wherein applying the second electrical signal in an acute therapy mode is triggered by the indication of the acute event where the acute therapy mode is implemented in a course that has a predetermined duration, the predetermined duration being independent of a change in an initiation signal for the second electrical signal.   
     
     
         16 . The system of  claim 15 , wherein the system is configured to apply the first electrical signal between a pulse range of about 2 pulses to about 10 pulses and having a microburst duration less than about 100 msec. 
     
     
         17 . The system of  claim 15 , wherein the system is configured to apply the first electrical signal between a pulse range of about 2 pulses to about 6 pulses and having a microburst duration in a duration range from about 20 msec to about 80 msec. 
     
     
         18 . The system of  claim 15 , wherein the system is configured to apply the second electrical signal at least about 100 pulses per burst and having a burst duration of at least about 2 sec. 
     
     
         19 . The system of  claim 15 , wherein the system is further configured to apply the first electrical signal to at least one of a left vagus nerve or a right vagus nerve. 
     
     
         20 . The system of  claim 15 , wherein the system is further configured to apply the second electrical signal to at least one of a left vagus nerve or a right vagus nerve.