Sleep Paralysis

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Related to Sleep Paralysis: Lucid Dreaming

sleep paralysis

[′slēp pə‚ral·ə·səs]
Transient paralysis with spontaneous recovery occurring on falling asleep or on awakening.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

Sleep Paralysis (Sleep Immobility)


Most people have had the experience of not being able to move in a dream. Being unable to run away from some kind of danger—or trying to run and being able to move only very slowly—is particularly common because at some level we know that we are paralyzed when we dream. During the rapid eye movement (REM) stage of sleep, when our most active dreams occur, a relay station at the top of the spinal column disconnects the motor cortex from the rest of the body, with the exception of the lungs and the eyes. This is why the neck muscles lose their tone during this stage, which is one of the defining characteristics of REM sleep.

Clearly this is a biological mechanism for preventing us from awakening otherwise we might thrash about during dreams. This disconnection of the motor impulses is the reason sleepwalking occurs only during non-REM sleep. It is also a factor in the sleep disorder referred to as sleep paralysis (which is distinct from normal REM sleep immobility), in which the sleeper is completely paralyzed immediately before entering (and sometimes immediately after leaving) sleep.

The Dream Encyclopedia, Second Edition © 2009 Visible Ink Press®. All rights reserved.
References in periodicals archive ?
She said: "Aside from a few social media groups, there's so little out there about sleep paralysis and no one seems to know much about it.
Najma Firas, 20, a Libyan-American student, said she experiences sleep paralysis about four nights a night.
However, as a number of participants in the present study discussed negative emotions in terms of fear and confusion, some of these cases could be related to sleep paralysis rather than anxiety.
The tetrad of EDS, cataplexy, sleep paralysis, and hallucinations is the hallmark of narcolepsy, though not all of the symptoms need be present (Table I).
SLEEP paralysis is a condition that strikes a person who is most often in a supine position and is about to drop off to sleep, or has just woken up, and realises that he or she is unable to move, speak, or cry out.
Hypnagogic and hypnopompic hallucinations are often associated with sleep paralysis. (3,4) These are visual, somatic, auditory or other hallucinations, usually brief though sometimes prolonged, that occur at the transition from wakefulness to sleep (hypnagogic hallucinations) or from sleep to wakefulness (hypnopompic hallucinations).
Sleep paralysis is caused by a biological function that has evolved to prevent our body moving around and causing physical injury while we are dreaming.
``With abduction cases, there are psychological explanations such as vivid dreams or sleep paralysis,but again there is a small hard core of cases which are extremely interesting.
Sometimes people with narcolepsy also suffer from a sudden loss of muscle function; a temporary kind of sleep paralysis; or hallucinations (often frightening) when falling asleep.
Symptoms of narcolepsy include excessive daytime sleepiness (even dropping off to sleep at any time, whether it be watching TV or driving a car), cataplexy (brief episodes of muscle weakness brought on by strong emotion), sleep paralysis (inability to move occurring at the moment of failing asleep), and hypnagogic hallucinations (dreamlike images that occur at sleep onset).
Cataplexy, sleep paralysis and hypnagogic/ hypnopompic hallucinations are all abnormal manifestations of REM sleep.[1,2,22] The muscle atonia in cataplexy and sleep paralysis is physiologically similar to the atonia occurring normally during REM sleep.[1] The visual, auditory or tactile hallucinations are physiologically similar to those sensations experienced during normal dreaming.[15]