System and method for characterizing brain states during general anesthesia and sedation using phase-amplitude modulation

Abstract

A system and method for monitoring and/or controlling a state of consciousness of a subject experiencing anesthesia are provided. In some aspects, the system includes a plurality of sensors placed about the subject and configured to acquire electroencephalogram (“EEG”) data therefrom while the subject is receiving anesthesia, and at least one processor configured to receive the EEG data from the plurality of sensors, and perform a phase-amplitude coupling analysis using the received EEG data to determine a phase-amplitude frequency distribution. The at least one processor is also configured to identify a state of consciousness of the subject using the determined phase-amplitude frequency distribution, and generate a report indicative of the state of consciousness of the subject.

1 . A system for monitoring consciousness of a subject experiencing anesthesia, the system comprising:
 a plurality of sensors placed about the subject and configured to acquire electroencephalogram (“EEG”) data therefrom while the subject is receiving anesthesia;   at least one processor configured to:
 receive the EEG data from the plurality of sensors; 
 perform a phase-amplitude coupling analysis using the received EEG data to determine a phase-amplitude frequency distribution; 
 identify a state of consciousness of the subject using the determined phase-amplitude frequency distribution; and 
 generate a report indicative of the state of consciousness of the subject. 
   
     
     
         2 . The system of  claim 1 , wherein the processor is further configured to determine a baseline phase-amplitude frequency distribution. 
     
     
         3 . The system of  claim 2 , wherein identifying the state of consciousness of the subject further comprises comparing the phase-amplitude frequency distribution to the baseline phase-amplitude frequency distribution. 
     
     
         4 . The system of  claim 1  wherein the processor is further configured to determine a polarity of a phase-coupling modulation associated with the received EEG data. 
     
     
         5 . The system of  claim 4 , wherein identifying the state of consciousness of the subject further comprises comparing the polarity of the phase-coupling modulation to a baseline polarity of the phase-amplitude modulation. 
     
     
         6 . The system of  claim 1 , wherein the processor is further configured to determine a spatial distribution of phase-amplitude coupling using the received EEG data. 
     
     
         7 . The system of  claim 1 , wherein identifying the state of consciousness of the subject further comprises correlating a dose of anesthesia with the determined phase-amplitude frequency distribution. 
     
     
         8 . The system of  claim 1 , wherein identifying the state of consciousness of the subject further comprises determining trough-max and peak-max modulation patterns. 
     
     
         9 . The system of  claim 8 , wherein the trough- and peak-max modulation patterns are correlated with distinct neural circuits to reflect distinct states of unconsciousness. 
     
     
         10 . The system of  claim 9 , wherein a transition into a trough-max modulation from a state of peak-max or intermediate state between trough- and peak-max indicates that the subject is recovering consciousness. 
     
     
         11 . The system of  claim 10 , wherein the trough-max state localized to anterior cingulate and frontal cortices indicates that a degree of internal consciousness may be present in the subject. 
     
     
         12 . The system of  claim 9 , wherein a transition to a peak-max state indicates a deeper level of impaired consciousness. 
     
     
         13 . The system of  claim 12 , wherein the peak-max state is identified as a state that precedes burst suppression. 
     
     
         14 . The system of  claim 8 , wherein the trough-max and peak-max modulation patterns are related to the likelihood that the subject could regain consciousness when presented external stimuli.