Is homeostatic sleep regulation under low sleep pressure modified by age?
STUDY OBJECTIVES: We have previously shown that healthy older volunteers react with an attenuated frontal predominance of sleep electroen-cephalogram (EEG) delta activity in response to high sleep pressure. Here, we investigated age-related changes in homeostatic sleep regulation under low sleep pressure conditions, with respect to regional EEG differences and their dynamics. DESIGN: Analysis of the sleep EEG during an 8-hour baseline night, during a 40-hour multiple nap protocol (150 minutes of wakefulness and 75 minutes of sleep) and during the following 8-hour recovery night under constant posture conditions. SETTING: Centre for Chronobiology, Psychiatric University Clinics, Basel, Switzerland PARTICIPANTS: Sixteen young (20-31 years) and 15 older (57-74 years) healthy volunteers INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: All-night EEG spectra revealed an increase in spindle activity (13-15.25 Hz) for both age groups, but only in the young did we find a significant decrease of de
