MICROSLEEP
Microsleep
A microsleep is a temporary episode of sleep which may last for a fraction of a second or up to thirty seconds where an individual fails to respond to some arbitrary sensory input. MSs occur when an individual loses awareness and subsequently gains awareness after a brief lapse in consciousness, or when there are sudden shifts between states of wakefulness and sleep. In behavioral terms, MSs manifest as droopy eyes, slow eyelid-closure, and head nodding. In electrical terms, microsleeps are often classified as a shift in electroencephalography during which 4–7 Hz activity replaces the waking 8–13 Hz background rhythm.The above text is a snippet from Wikipedia: Microsleep
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