Influence of propofol on the electroencephalogram default mode network in patients of advanced age

OBJECTIVE: This study was performed to evaluate the effects of propofol on the electroencephalogram (EEG) default mode network (DMN) in patients of advanced age. METHODS: Fifteen men aged >60 years (mean, 70 years) were selected. Propofol target-controlled infusion was performed under EEG bispectral index monitoring. The propofol target effect-site concentration, blood pressure, heart rate, and distributions and powers of the EEG spectrum were recorded in an awake state and under anesthesia. The EEG included seven bands: delta (0.5–3.5 Hz), theta (4.0–7.0 Hz), alpha-1 (7.5–9.5 Hz), alpha-2 (10–12 Hz), beta-1 (13–23 Hz), beta-2 (24–34 Hz), and gamma (35–45 Hz). RESULTS: From an awake state to anesthesia, the brain topographic map showed that the energies of delta, theta, alpha-1, alpha-2, and beta-1 were concentrated in the frontoparietal site, and the power increased significantly. The energy distribution of beta-2 was significantly decreased and the power significantly reduced. The energy distribution of gamma in the temporal lobe was also markedly decreased and the power significantly reduced. CONCLUSIONS: This study revealed the changes in the spatial distribution and regional energy of the EEG DMD in men of advanced age from the awake state to the anesthetized state.