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The term polyphasic sleep was first used in the early 20th century by psychologist J. S. Szymanski, who observed daily fluctuations in activity patterns. [2] It does not imply any particular sleep schedule. The circadian rhythm disorder known as irregular sleep-wake syndrome is an example of polyphasic sleep in
One of the important questions in sleep research is clearly defining the sleep state. This problem arises because sleep was traditionally defined as a state of consciousness and not as a physiological state, [14] [15] thus there was no clear definition of what minimum set of events constitute sleep and distinguish it from other states of partial or no consciousness.
After sustained periods of sleep, both the speed and synchronicity of the neurons firing are shown to decrease. [5] Another effect of wakefulness is the reduction of glycogen held in the astrocytes, which supply energy to the neurons. Studies have shown that one of sleep's underlying functions is to replenish this glycogen energy source. [6]
Circadian rhythm sleep disorders (CRSD), also known as circadian rhythm sleep–wake disorders (CRSWD), are a family of sleep disorders that affect the timing of sleep. CRSDs cause a persistent pattern of sleep/wake disturbances that arise either by dysfunction in one's biological clock system, or by misalignment between one's endogenous oscillator and externally imposed cues.
Hori et al. regard sleep onset hypnagogia as a state distinct from both wakefulness and sleep with unique electrophysiological, behavioral and subjective characteristics, [10] [12] while Germaine et al. have demonstrated a resemblance between the EEG power spectra of spontaneously occurring hypnagogic images, on the one hand, and those of both ...
EMG (electromyography) is a crucial method to distinguish between sleep phases: for example, a decrease of muscle tone is in general a characteristic of the transition from wake to sleep, [5] [6] and during REM sleep, there is a state of muscle atonia (paralysis), resulting in an absence of signals in the EMG. [5]
It has been shown that the sleep-wake cycle acts on the beta-amyloid burden, which is a central component found in AD. [19] [18] As individuals awaken, the production of beta-amyloid protein will be more consistent than its production during sleep. [19] [18] [21] This is explained by two phenomena. The first is that the metabolic activity will ...
Patients have a relatively severe to absolute inability to advance the sleep phase to earlier hours by enforcing conventional sleep and wake times. Sleep–wake logs and/or actigraphy monitoring for at least two weeks document a consistent habitual pattern of sleep onsets, usually later than 2 am, and lengthy sleeps.