Age-Related Electroencephalographic Delta and Alpha Oscillations During Sedation with Target-Controlled Propofol Infusion

<b>Background/Objectives</b>: Previous studies have reported decreases in delta and alpha power with aging under propofol anesthesia, often confounded by reduced target concentrations in older patients. This study aimed to investigate electroencephalography (EEG) dynamics under propofol sedation using target-controlled infusion (TCI) while maintaining consistent effect-site concentrations across age groups. <b>Methods</b>: We conducted a comparative observational study of 44 patients scheduled for orthopedic upper extremity surgery under regional anesthesia. Patients were categorized into the younger (20-39 years, <i>n</i> = 23) and older (50-69 years, <i>n</i> = 21) age groups. EEG data were recorded from four frontal electrodes, with a specific focus on delta and alpha frequency bands, while the effect-site concentration of propofol was maintained at 3.0 μg/mL using TCI. <b>Results</b>: TCI-adjusted propofol administration with the same target concentration results in different total drug delivery between the two age groups, according to age-related pharmacokinetic differences. The younger age group exhibited higher delta power, indicating an age-associated decline. Alpha power remained stable across age groups despite the differences in drug delivery, while older patients demonstrated decreased frontal alpha synchronization, highlighting age-related changes in brain connectivity. <b>Conclusions</b>: This study demonstrates that delta power decreases with age, even under standardized propofol concentration, while alpha power remains consistent, suggesting its possibility as an indicator of sedation depth. In contrast, the variations in delta power and alpha connectivity in different age groups suggest the need for age-specific anesthesia dosing to enhance safety and efficacy. Therefore, these findings contribute to a better understanding of age-related neurophysiological responses to anesthesia.