“There was this constant, overwhelming exhaustion. It didn't matter how much I slept.” – Scott
Wakefulness, normally promoted during the biologic day,7 is characterized by high muscle tone, fast-frequency neuronal activity, and is necessary for alertness and higher-order neurocognitive functioning.3,5,7
Non-REM sleep is a state with slower-frequency neuronal activity and light to deep stages of sleep; skeletal muscle tone is lower than during wakefulness.3,5 Nighttime sleep normally begins with an episode of non-REM sleep.3
During REM sleep, which is associated with dreaming and skeletal muscle atonia, neuronal activity is faster and desynchronized, with distinct wave patterns (e.g., sawtooth waves) on electroencephalogram (EEG).3,5,8 Episodes of REM sleep typically occur after non-REM sleep and become longer over the course of the night.3
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- Pearl PL, LaFleur BJ, Reigle SC, et al. Sawtooth wave density analysis during REM sleep in normal volunteers. Sleep Med. 2002;3(3):255-258.