Fig. 5.

Scatter plots from 24 hours of simultaneous paired recordings using identical sensors placed in the left and right frontal lobe parenchyma of a patient. Each subfigure corresponds to a time point as indicated by the plot label. Recent data points are plotted in color against a background of past data (red and blue points correspond to data from the right and left hemispheres, respectively), with past data plotted in gray (darker shades indicate later data points). The data shown in this figure indicate that even within an individual patient the short-term linear relationship between static and pulsatile ICPs undergoes abrupt shifts and gradual drifts. The shift phenomenon is evident from the relative movement of the right- and left-hemisphere trend lines from one frame to the next, while the drift phenomenon is illustrated by the movement of recent data points relative to the background of past data.