Preoperative frontal EEG power spectral features associated with psychomotor subtypes of postoperative delirium in cardiovascular surgery: a prospective study

Postoperative delirium (POD) is associated with complications following cardiovascular surgery, and its psychomotor subtypes differ in clinical course and treatment responsiveness, underscoring the importance of personalized preventive strategies. We aimed to investigate preoperative neurophysiological characteristics associated with POD and its psychomotor subtypes in patients undergoing cardiovascular surgery. This prospective, single-center study included 209 patients undergoing cardiovascular surgery. Preoperative frontal electroencephalography (EEG) was recorded using a patch-type device with three electrodes (left, center, and right). Standardized mean power spectral density of the following frequency bands was calculated: theta (4-8 Hz), alpha (8-13 Hz), beta (13-30 Hz), gamma1 (30-59 Hz), and gamma2 (61-75 Hz). Delirium and its psychomotor subtypes were assessed until postoperative day 7. EEG features were compared between patients with and without POD and among psychomotor subtypes, with adjustment for multiple comparisons. POD occurred in 70 patients (33.5%). No significant differences in preoperative EEG power were observed between patients with and without POD. However, patients with the hyperactive-or-mixed subtype demonstrated significantly higher theta and lower alpha activity than those with the hypoactive or no motor subtypes. These findings may identify neurophysiological markers associated with underlying psychomotor symptoms in delirium and may inform preoperative subtype risk stratification.Trial registration: UMIN-CTR (ID: UMIN000049390).