Electroencephalographic Monitoring in the Recovery Room for Identification of Patients at Risk for Postoperative Delirium

BACKGROUND: Electroencephalography (EEG), especially the assessment of alpha oscillations (8-12 Hz), has gained attention as a non-invasive marker of neural network integrity, with reduced alpha power linked to thalamocortical disconnectivity and increased vulnerability to postoperative delirium (POD) in elderly patients. Recent studies have demonstrated that altered EEG dynamics in the alpha-band frequencies during anesthesia emergence in the post-anesthesia care unit (PACU) are associated with POD. However, EEG data postoperatively from the recovery room are scarce. METHODS: This prospective observational study (2019-2022) at Charité-Universitätsmedizin Berlin investigates frontal EEG signatures and postoperative delirium (POD) in older adults undergoing surgery. Postoperative POD screening was performed in the recovery room and twice daily for five days. While the overall study collected pre- and intraoperative EEGs, we focus here on frontal EEG files recorded in the recovery room while patients were awake. Spectral-domain EEG features and monitor-derived indices were compared by multivariable regression analysis between those who developed POD and those who did not. RESULTS: A total of 184 patients had sufficient EEG data for analysis; 57 (31%) developed POD. Recovery-room recordings showed significantly reduced alpha- and beta-band power in POD vs NoPOD patients with cumulative 10-20 Hz power providing the best discrimination (AUC 0.69, 95% CI 0.60-0.77). NoPOD patients exhibited increases in alpha- and beta-band power (8-20 Hz) relative to preoperative baseline, with highest augmentation at approximately 16 Hz, whereas POD patients retained spectral patterns comparable to baseline across all frequency bands. CONCLUSIONS: These data suggest that frontal EEG monitoring in the recovery room can help identify a "vulnerable brain" phenotype associated with increased POD risk. Integrating this monitoring into postoperative care may support risk stratification and more individualized management.