Connectivity Analysis of Full Montage EEG in Traumatic Brain Injury Patients in the ICU

Long-term full montage (19 channels) electroencephalographic (EEG) recordings of 6 patients, treated in the Intensive Care Unit (ICU) for severe Traumatic Brain Injury (TBI), were analyzed using the methodology of connectivity analysis. Two connectivity measures, Coherence and Cross Frequency Coupling (CFC) were calculated for each pair of channels in two frequency bands, 8-13 Hz and 13-35 Hz. In the case of CFC, frequencies below 2 Hz were considered as the modulating rhythm. The ability of the measures to indicate the outcome of treatment was evaluated using the Mann-Whitney U-test. The results indicate that CFC values tend to be higher in good outcome patients for (modulating) frontal EEG channels. For the Coherence measure, U-statistic values close to 0.9 were obtained for some channel pairs, however, no clear pattern could be observed.