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Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain sensory activity is inhibited. During sleep, there is a marked ...
Sleep deprivation, also known as sleep insufficiency [2] or sleeplessness, is the condition of not having adequate duration and/or quality of sleep to support decent alertness, performance, and health. It can be either chronic or acute and may vary widely in severity.
Sleep paralysis is a state, during waking up or falling asleep, in which a person is conscious but in a complete state of full-body paralysis. [1] [2] During an episode, the person may hallucinate (hear, feel, or see things that are not there), which often results in fear. [1] [3] Episodes generally last no more than a few minutes. [2]
Sample hypnogram showing one sleep cycle (the first of the night) from NREM through REM. The sleep cycle is an oscillation between the slow-wave and REM (paradoxical) phases of sleep. It is sometimes called the ultradian sleep cycle, sleep–dream cycle, or REM-NREM cycle, to distinguish it from the circadian alternation between sleep and ...
The sleep disturbance causes clinically significant distress or impairment in social, occupational, educational, academic, behavioral, or other important areas of functioning. The sleep difficulty occurs at least three nights per week. The sleep difficulty is present for at least three months.
Sleep-talking can also be caused by depression, sleep deprivation, day-time drowsiness, alcohol, and fever. It often occurs in association with other sleep disorders such as confusional arousals, sleep apnea, and REM sleep behavior disorder. In rare cases, adult-onset sleep-talking is linked with a psychiatric disorder or nocturnal seizure. [2]
In individuals deprived of sleep, somnolence may spontaneously dissipate for short periods of time; this phenomenon is the second wind, and results from the normal cycling of the circadian rhythm interfering with the processes the body carries out to prepare itself to rest. The word "somnolence" is derived from the Latin "somnus" meaning "sleep".
Sleep inertia is a physiological state of impaired cognitive and sensory-motor performance that is present immediately after awakening. It persists during the transition of sleep to wakefulness, where an individual will experience feelings of drowsiness, disorientation and a decline in motor dexterity.