Figure 1.
Figure 1 demonstrates the conversion from the raw EEG signal to phase synchrony. Panel A shows the placement of the 19 scalp electrodes, with Pz’ (Pz prime) as the reference electrode. Panel C, below it, shows a typical, slow EEG recording (∼1 Hz) of a patient in coma. The green vertical lines represent 1 second. Panel B shows one method of representing phase synchrony values. The headplot corresponds to the electrode placement in panel A, where each black dot represents one of the 19 electrodes (the reference electrode is not shown). The phase synchrony values from 0 to 1 are the average value for the 10 second recording. The values at each electrode are colour coded with an R value = 0 for the 10 seconds represented as blue to a maximal synchrony, R = 1, represented as red. Panel D corresponds to an excerpt of the 10 second recording in panel C. Panel C is a 5 second excerpt of the digital EEG recording, where the rows from top to bottom represent the 19 electrodes, and the time in seconds is on the x axis. The phase synchrony values (0, blue to 1, red) are calculated for each second of the recording and are mapped over the 8 second time epoch.
Table 1.
Patient demographics.
Table 2.
Mean R indices, spatio-temporal variability and outcome.
Table 3.
Spatial complexity by EEG electrodes.