Frequency Characteristics of Sleep

Abstract One of the primary clinical uses of EEG is to assess sleep. EEG can be employed to examine REM and non-REM sleep. However, recording and analyzing EEG during sleep presents unique challenges relative to traditional awake EEG recording and analysis. This chapter provides guidance on meeting these challenges in order to record high-quality EEG during sleep and assess the data in the frequency domain. Beyond a general overview of the major power spectral features of REM and NREM dependent EEG activity, the chapter focuses on hallmark oscillatory elements of sleep such as slow waves (delta band) and sleep spindles (sigma band) in the context of neurophysiological mechanisms, detection methods, individual differences, and significance for cognition and brain health across the lifespan. Finally, yet importantly, the chapter provides a brief overview of the circadian system and sleep-wake homeostasis and their dynamic interaction in modulating EEG activity across vigilance stages in men and women.