Coma is a state of suppressed consciousness in which a person fails to react normally at external stimuli and does not initiate voluntary actions. With deepening of coma, the electroencephalographic cerebral activity (EEG) progresses from continuous oscillations to “isoelectric line” through a transitional discontinuous period consisting of “bursts” of large amplitude oscillations (lasting typically a couple of seconds) on a “suppressed” electrical background of increasing duration referred to as the burst-suppression pattern (BS).
Considering the emerging concept that all bursts are in fact triggered by competing internal and external stimuli largely unpredictable, it is unlilkely that an optimal index for cortical function monitoring during BS-coma can be derived by analyzing the statistical properties of “spontaneous” BS. Our novel hypothesis is that the changes in bursting rate during controlled external stimulation (BS reactivity) will better reflect the degree of cortical network dysfunction during BS coma than the “spontaneous” bursting rate.
The primary objective of this proposal is to design a “Coma EEG reactivity Monitor” (CERMO), suitable for clinical use, with particular emphasis on BS-coma. Our work plan includes: 1) hardware design combining an EEG signal processor with a programmable stimulus generator capable of applying visual, transcranial (direct current), magnetic and peripheral nerve stimulation to drive BS patterns with software designed for BS monitoring based on retrospective animal and clinical EEG recordings; 2) optimization and testing on prospective BS recordings in rats 3) a multi-centric clinical trial comparing the prognostic value of triggered versus „spontanous” BS patterns using our device and 4) certification.
To the best of our knowledge, there are no other commercially available devices designed specifically to monitor EEG/BS reactivity. We expect that CERMO will become a valuable tool to help predict the outcome of severe coma.