Figure 2. The mean percent time of time spent awake after falling asleep (WASO) is plotted for patients with no delirium (solid line) vs. those with delirium (dotted line) for the 6 monitoring periods (nightly for three nights before surgery and three nights after surgery).

The error bars are mean ± standard error. *p value of Mann-Whitney U test at that monitoring period is less than 0.05.