What Every Lucid Dreamer Should Know About Sleep Paralysis
Version 0.2
Many lucid dreamers who are trying to WILD are as part of that process trying to achieve something they call "sleep paralysis". What exactly is it? Why would they want it? And how important is it? I'll try to answer these three questions in this article.
By the way, if you think this article looks too long to read, just scroll down to "Conclusions".
What is Sleep Paralysis?
Unfortunately the term sleep paralysis can mean several different things to different people. I'll go through the main interpretations here. Some people would label this discussion as just semantics. I agree, except for the word "just". If a particular terminology creates confusion instead of enabling unambiguous communication, it has failed miserably.
Sense 1: Sleep Paralysis as REM Atonia
One interpretation of the term sleep paralysis is as a natural phenomenon that is more properly called REM atonia.[1] When you fall asleep you first go into non-REM sleep stages. In these sleep stages the tone (tension) of your skeletal muscles is reduced, that is, you become physically relaxed. You can still move, even though movements may be sluggish. For example, you can turn around in your sleep.
When you enter the REM stage, the skeletal muscles (except for the eye muscles and the diaphragm) become paralyzed. Since there is practically no muscle tone at all, this is called REM atonia. When you exit the REM stage, the muscles go back to the reduced muscle tone of non-REM sleep.
There are two ways that REM atonia could go wrong: it could be activated outside of REM sleep, or it could fail to be activated during REM sleep. The former type of failure results in a sleep disorder that I'll discuss in the next section. The latter type of failure is a more serious type of disorder called REM sleep behavior disorder (RBD) that causes people to act out their dreams during REM sleep.[2]
Sense 2: Sleep Paralysis as a Sleep Disorder
In the scientific and medical communities sleep paralysis usually refers to a sleep disorder.[3] The main symptom is that the subject is awake but unable to move or speak. This paralysis is usually accompanied by fear. The prevalent hypothesis is that sleep paralysis is REM atonia that has somehow been activated outside of REM sleep.[4]
When sleep paralysis occurs it is most often a brief episode when waking up and rarely when falling asleep. In rare cases the paralysis may last for as much as seven or eight minutes and be accompanied by nightmare like hallucinations.[5] This is also known as the "Old Hag" syndrome.
Sleep paralysis affects a minority of the population, and those who are affected experience it infrequently.[6]
Sense 3: Sleep Paralysis as Hypnagogic Hallucinations
There is not much justification for the use of the term "sleep paralysis" in the sense "hypnagogic hallucinations". However, LaBerge speaks of hypnagogic hallucinations as "the harbingers of REM sleep paralysis", so it's not unlikely that some people may have assumed they had to be the same phenomenon.
Hypnagogic states occur in the transition from wakefulness to sleep. By definition they are related to sleep stage 1, but they have also been known in some cases to occur in periods of reduced wakefulness before sleep. With respect to EEG, hypnagogic states are associated with a dropoff in alpha activity. Hypnic jerks (also known as sleep starts) occur in the hypnagogic states.[7]
There are also similar states in the transition from sleep to wakefulness called hypnopompic states. However, it's more difficult to tell hypnopompic states from dreams. Sometimes, for simplicity, hypnopompic states are also called hypnagogic.
In hypnagogic states people may experience hallucinations. Hallucinations, including hypnagogic ones, are experienced as if you had actually perceived them through your senses, and they may involve any and all of your senses.[7] The most common ones are:
- Visual HH, also known as hypnagogic imagery (HI), are typically faces, landscapes, geometric shapes.
- Auditory HH are typically roaring sounds, explosions, people shouting.
- Kinesthetic, vestibular, tactile HH are typically vibrations, the feeling of being electrocuted (sans the pain), a sense of extreme acceleration.
Sense 4: Sleep Paralysis as an Umbrella Term
This interpretation includes a hodgepodge of any or all of the preceding interpretations.
Why Would Lucid Dreamers Want Sleep Paralysis?
In order to discuss this the distinctions made in the previous section are crucial. So let's go through them one by one.
Sense 1: Why Would LDers Want Sleep Paralysis as in REM Atonia?
Every normal person will get REM atonia during REM sleep, and only during REM sleep. They will also be oblivious to the fact that they are in REM atonia.
In wakefulness your sensory perceptions are externally generated from your sensory organs, and you control your physical body through your voluntary muscles. In REM sleep the exact opposite is the case: your sensory perceptions are internally generated, and you control your dream body. [8] For this reason you won't be aware that your body is paralyzed.
So wanting sleep paralysis as REM atonia is pointless. If you have a normal physiology you are guaranteed to get REM atonia in REM sleep, but you won't be aware of this since your entire experience will be internally generated during that entire period of time.
Sense 2: Why Would LDers Want Sleep Paralysis as in the Sleep Disorder?
People who suffer from sleep paralysis generally do not want it because it's usually very frightening. A minority of the population will get sleep paralysis sometimes. The proportion of the population that experience sleep paralysis regularly is very small.
Those who suffer from sleep paralysis may exploit it to launch into WILDs when they get it. Those who don't have this disorder will likely not get it by wishing for it. You won't be able to "will" yourself into changing your sleep physiology so that you get REM atonia outside of REM sleep. At least I'm not aware of any kind of research that could confirm such an effect.
So wanting sleep paralysis as a disorder is also pointless. If you have it you can use it to your advantage, and if you don't have it you won't get it by thinking hard about it.
Sense 3: Why Would LDers Want Sleep Paralysis as in Hypnagogic Hallucinations?
Whenever we fall asleep we pass through hypnagogic states. We are not usually aware of this, or at least we don't remember it. But LDers who want to WILD need to maintain awareness all the way into sleep, so it's highly likely that if they get any HH they will recall it because they were aware at the time.
Thus, wanting HH may make some sense for LDers. It's not that HH will buy them anything in itself (unless they like the HH for their own sake), but if they get HH it's a symptom that they have managed to keep themselves "awake" beyond the point where most people lose awareness. And that's a good sign, because it means that they may not be far away from entering a dream.
On the other hand this may cause problems too, because not everyone gets any significant HH, at least not every time they fall asleep. So if you think you should get these HH and then you don't maybe that will stop you in your efforts and discourage you from trying again.
The conclusion is that if you get HH it's an indication that you're on the right track, but if you don't get them it's
not an indication that you're on the wrong track. HH are a potential side effect of WILDing and absence of HH doesn't mean anything. BillyBob, author of several WILD guides on DV, explicitly recommends that you don't focus on HH, because that focus may actually prevent you from entering the dream.[9]
Sense 4: Why Would LDers Want Sleep Paralysis as in the Umbrella Term?
This is harder to answer. Since sleep paralysis in this sense is a hodgepodge of different things whose content may vary a lot between individuals, it's not at all clear what it is they want.
Many LDers seem to conflate hypnagogic hallucinations and REM atonia. Hypnagogic hallucinations belong exclusively to sleep stage 1 (or in rare cases wakefulness)[7]. And REM atonia belongs exclusively to the REM stage.[14] Since sleep stages 1 and REM are distinct, these two phenomena do not normally occur simultaneously, except in the case of sleep paralysis as a disorder.
So is it possible that REM could follow shortly after falling asleep? Yes, after a brief awakening (like a few tens of seconds) from REM sleep you can expect to fall right back into REM sleep.[13] After a longer awakening (one and a half hours) it usually takes at least fifteen minutes to reach REM.[10] I don't have any hard data for a WBTB awakening (30 to 60 minutes), but it would be reasonable to expect the time needed to reach REM to be closer to the latter interval than the former.
Many people who WILD and enter a dream after falling asleep consciously, conclude that they must be in REM sleep. However, this does not follow, because it's possible to dream in any sleep stage. Generally the most vivid dreams occur in REM sleep, but it's possible to dream in any sleep stage. Especially dreams in stages 1 and 2 can be indistinguishable from REM dreams.[11] Even lucid dreams have been verified in sleep stages 1 and 2.[12] So a dream, even a vivid or lucid one, does not necessarily mean that you're in REM sleep.
Now if REM atonia is required to keep us from acting out our dreams and we can dream in any sleep stage, then why don't we need atonia in
all sleep stages? I'm not sure anyone knows the complete answer, but at least it's a fact that the brain is in a very different state in REM sleep compared to non-REM sleep.[8] Also, in the cases of sleepwalking and sleep terrors, which both occur in deep sleep (stages 3 and 4), people
do move around in their sleep.
Conclusions
Before you decide that sleep paralysis is something you desperately need, take a moment to consider the following facts. Of the 333 pages of
Exploring the World of Lucid Dreaming, LaBerge devotes only about four pages in total to sleep paralysis (either as REM atonia or the disorder). He describes eight different techniques to induce WILDs, but only two of them even mention sleep paralysis. And BillyBob, a seasoned lucid dreamer on DV and author of several WILD guides, explicitly recommends not to focus on sleep paralysis.
If you are one of the few people who get sleep paralysis as a disorder, you can know that although it may be scary, it's not in any way dangerous. And you can even turn it into an advantage by initiating WILDs from this state.
If you belong to the majority who don't get sleep paralysis as a disorder, don't sweat it. You will get REM atonia for sure, but by that time your experience is entirely internally generated and you won't have any awareness of your physical body. You
may get hypnagogic hallucinations, and if you get them you'll know that you're on the right path to a WILD. If you don't get them, don't worry; you'll be able to WILD just fine anyway, as thousands of people have done before you.
Acknowledgements
Thanks to those who challenged my posts on this subject and made me do more research, and to those who commented on version 0.1. Special thanks to Shift who dug up facts and references and prodded me to write this article.
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Notes and References
1
"REM atonia abbrev. An inhibition of skeletal muscles (but not extra-ocular muscles) during REM sleep, manifested as complete atonia, that is governed by a small inhibitory centre in the pons called the subcoerulear nucleus and by the magnocellular nucleus in the medulla oblongata to which it is connected, and that prevents spinal nerves from activating skeletal muscles and thereby stops dreams from being acted out by the sleeper. The only observable bodily movements in a person in REM sleep, apart from breathing and rapid eye movements, are occasional twitches of the extremities, except in people with REM behaviour disorder."
Excerpt from A Dictionary of Psychology 2001, originally published by Oxford University Press 2001.
Stephen LaBerge, researcher and author of the classical work
Exploring the World of Lucid Dreaming, is one notable expert who uses the term "sleep paralysis" in the sense of "REM atonia".
2
"REM behaviour disorder abbrev. A condition is which REM atonia does not function during episodes of dreaming. People with this disorder thrash violently about, leap out of bed, and sometimes attack bed-partners during REM sleep. It is assumed to be due to a lesion in the subcoerulear nucleus or the magnocellular nucleus."
Excerpt from A Dictionary of Psychology 2001, originally published by Oxford University Press 2001.
For more information, see
REM Sleep Behavior Disorder at SleepEducation.com.
3
"sleep paralysis n. A condition in which REM atonia is experienced in the waking state. Such episodes typically occur immediately after waking or shortly before falling asleep. They are often frightening and may be accompanied by out-of-body experiences."
Excerpt from A Dictionary of Psychology 2001, originally published by Oxford University Press 2001.
Some people who use the term "sleep paralysis" to mean REM atonia use the term "isolated sleep paralysis" to refer to the disorder, in order to distinguish the two concepts. LaBerge, in
Exploring the World of Lucid Dreaming, uses "sleep paralysis" to refer to both the disorder and REM atonia.
For more information, see
Sleep Paralysis at SleepEducation.com.
4
Physiology of REM sleep, cataplexy, and sleep paralysis. Hishikawa Y, Shimizu T.
5
There are two major types of sleep paralysis.
- Common sleep paralysis (CSP), also known as typical sleep paralysis. CSP is short lasting, and it usually occurs when waking up and rarely when falling asleep.
- Hallucinatory sleep paralysis (HSP), also known as hypnagogic sleep paralysis. HSP is accompanied by nightmare like hallucinations. HSP can last as long as seven or eight minutes. HSP is rare and seems to be geographically episodic.
For more information, see
Sleep Paralysis at Night Terrors Resource Center.
6
Scientific studies say that the risk of getting sleep paralysis is small:
"Isolated Sleep Paralysis (SP) occurs at least once in a lifetime in 40-50% of normal subjects, while as a chronic complaint it is an uncommon and scarcely known disorder."
Buzzi G, Cirignotta F. Isolated sleep paralysis: a web survey. Sleep Res Online 2000;3(2):61-6.
"To further examine the incidence of sleep paralysis, the responses of 80 first-year medical students, 16.25% had experienced predormital, postdormital, or both types of sleep paralysis. These episodes occurred infrequently-- only once or twice for most of these students."
Penn NE, Kripke DF, Scharff J. Sleep paralysis among medical students. J Psychol 1981 Mar;107 pt 2:247-52.
7
"Hypnagogic states are transient states of decreased wakefulness characterized by short episodes of dreamlike sensory experience. These phenomena were first described by J. Müller (1826/1967) as "fantastic visual phenomena" (p. 20ff) occurring usually, but not exclusively, at sleep onset. Maury (1848) coined for them the term hypnagogic, from Greek hypnos (sleep) and agogo (I bring). Schacter (1976) described them as "dreamlets." Subjects usually report short visual percepts like faces, landscapes, and natural or social scenes that may or may not be related to previous daytime experience. These percepts may be of pseudohallucinatory (i.e., with preserved insight of unreality) or truly hallucinatory (i.e., experienced as if real) character. In contrast to dreams, hypnagogic experiences are usually rather static, without narrative content, and the subject is not involved as an actor (cf. Sleep and Dreaming section)."
"Similar phenomena occurring at the transition from sleep to wakefulness are called hypnopompic (Myers, 1904); here, however, it is difficult to differentiate hypnagogic imagery from remnants of dream imagery. Hypnagogic-like phenomena may also occur in daytime periods of reduced wakefulness and possibly superimposed over adequate sensory perceptions of the environment (cf. Mavromatis, 1987; Schacter, 1976; Sherwood, 2002). Subjective experience in hypnagogic states comprises vivid, mostly very brief episodes of usually visual (86%) and acoustical (8%) imagery with other sensory modalities occurring less frequently and with an average recall rate of 35%. There is more awareness of the real situation in hypnagogic states than in dreaming (Hori et al., 1994). The prevalence for frequent hypnagogic states is estimated at 37% (Ohayon, Priest, Caulet, & Guilleminault, 1996). Behavioral correlates are sparse, for example, leg or arm jerks ("sleep starts") associated with illusionary body movements (American Sleep Disorders Association, 1990; Sherwood, 2002). As for physiological correlates, an association between short flashes of dreamlike imagery and drop-offs in alpha EEG activity was first noticed by Davis et al. (1937). By definition, hypnagogic states are related to sleep onset, that is, Sleep Stage 1 according to Rechtschaffen and Kales (1968), but may occur even with presleep alpha EEG (Foulkes & Schmidt, 1983; Foulkes & Vogel, 1965). Kuhlo and Lehmann (1964) studied hypnagogic states and their EEG correlates during drowsiness and sleep onset: Spontaneous, transient, fragmentary nonemotional visual and auditory impressions of varying complexity were reported that were mostly experienced as unreal and were associated with flattened or decelerated alpha and/or slow theta EEG activity; the authors postulated a gradual progression from hypnagogic hallucinations to fragmentary dreams (cf. Lehmann et al., 1995)."
Dieter Vaitl et al. Psychobiology of Altered States of Consciousness. Psychological Bulletin 2005, Vol. 131, No. 1.
8
REM sleep is in many ways the polar opposite of wakefulness, with non-REM sleep falling somewhere in the middle. In particular, in REM sleep the sensory experience and body control are maximally internal
Awake state:
- Brain chemistry is modulated by norepinephrine and serotonin
- You perceive the world through your senses and control your physical body
REM sleep:
- Brain chemistry is modulated by choline
- Perceptions are internally generated and you control your dream body. Sensory input is by no means impossible in REM sleep, but the threshold is higher than in the other states.
You may think of the states of sleep falling along a line like this:
Wakefulness --------------- non-REM ----------------- REM
The notorious exception to this is the activation level of the brain. If you look at the brain waves on an EEG machine, REM sleep EEG looks very similar to EEG of wakefulness (high frequency, low amplitude), whereas the EEG of non-REM sleep is very different from both of the others (low frequency, high amplitude). So with respect to EEG, the states of sleep look something like this:
Wakefulness, REM ----------------------------------- non-REM
Source: Hobson, J. Allan, Pace-Schott, E. and Stickgold, R., Dreaming and the Brain: Toward a Cognitive Neuroscience of Conscious States, Behavioral and Brain Sciences, 23 (6), 2000.
9
DV member BillyBob is the author of several WILD guides. Here are some excerpts:
"When learning to WILD, the majority of people learn about these crAzY things like "Hypnogogic Imagery, Sleep Paralysis, Auditory Hallucinations, etc." and are then told that these things "lead up to" dreams. What happens when they lay down to WILD? They subconsciously tell themselves "watch out for hypnogogia/paralysis/voices as these things mean you are closer to lucidity!" This is the exact equivalent of what the prehistoric human thought. This is the exact thing the system watches for to keep you from falling into your dreams!"
BillyBob. WILD.
"For starters, you absolutely should NOT be waiting for HI or any other thing that people say they see, I myself rarely feel SP or see HI, I don't "see" anything because I'm so focused on my breathing."
BillyBob. WILD - The Guide To End All Guides
10
REM latency is the time span between the start of sleeping and the start of REM sleep. This is normally 90 minutes. In a multiple sleep latency test (MSLT) the subject tries to take five daytime naps at two hour intervals after having first slept for at least six hours during the night. The first nap trial begins between 1.5 and three hours after waking up.
Source: MSLT at SleepEducation.com.
"In an MSLT, REM sleep during the first 15 minutes of sleep is called sleep onset REM (SOREM). The occurrence of SOREM is indicative of severe sleep deprivation or narcolepsy and is almost exclusive to these conditions."
Source: Narcolepsy at Sleepchannel.
Unfortunately the REM latency test or the MSLT do not exactly duplicate the typical situation for lucid dreaming attempts, which normally employ the wake back to bed (WBTB) technique.
11
"It is generally accepted that NREM mentation which is indistinguishable from REM dreaming does indeed occur. Monroe et al's (1965) widely cited study suggests that approximately 10-30% of NREM dreams are indistinguishable from REM dreams (Rechtschaffen 1973). Even Hobson accepts that 5-10% of NREM dream reports are `indistinguishable by any criterion from those obtained from post-REM awakenings' (Hobson 1988, p. 143). If we adjust this conservative figure to account for the fact that NREM sleep occupies approximately 75% of total sleep time, this implies that roughly one quarter of all REM-like dreams occur outside of REM sleep."
This is an example of a non-REM dream report:
"I was with my mother in a public library. I wanted her to steal something for me. I've got to try and remember what it was, because it was something extraordinary, something like a buffalo head that was in this museum. I had told my mother previously that I wanted this head and she said, all right, you know, we'll see what we can do about it. And she met me in the library, part of which was a museum. And I remember telling my mother to please lower her voice and she insisted on talking even more loudly. And I said, if you don't, of course, you'll never be able to take the buffalo head. Everyone will turn around and look at you. Well, when we got to the place where the buffalo head was, it was surrounded by other strange things. There was a little sort of smock that little boys used to wear at the beginning of the century. And one of the women who worked at the library came up to me and said, dear, I haven't been able to sell this smock. And I remember saying to her, well, why don't you wear it then? For some reason or other I had to leave my mother alone, and she had to continue with the buffalo head project all by herself. Then I left the library and went outside, and there were groups of people just sitting on the grass listening to music."
Solms, Mark. Dreaming and REM Sleep Are Controlled by Different Brain Mechanisms, Behavioral and Brain Sciences 23 (6), 2000.
"Sleep Onset (SO). Perhaps the most vivid NREM mentation reports have been collected from SO stages. These include images from the Rechtschaffen and Kales stages 1 and 2 of sleep (Cicogna et al. 1991; Foulkes et al. 1966; Foulkes & Vogel 1965; Vogel 1991; Lehmann et al. 1995) as well as from the stages of a more detailed SO scoring grid (Hori et al. 1994; Nielsen et al. 1995). SO mentation is remarkable because it can equal or surpass in frequency and length mentation from REM sleep (Foulkes et al. 1966; Vogel et al. 1966; Foulkes & Vogel 1965; Vogel 1978; Foulkes 1982). Moreover, much SO mentation (from 31-76% depending upon EEG features) is clearly hallucinatory dreaming as opposed to isolated scenes, flashes or nonhallucinated images (Vogel 1978)."
Nielsen, Tore A. Mentation in REM and NREM Sleep: A review and possible reconciliation of two models, Behavioral and Brain Sciences 23 (6), 2000.
12
"After being instructed in the method of lucid dream induction (MILD) described by LaBerge (1980b) the subjects were recorded from 2 to 20 nights each. In the course of the 34 nights of the study, 35 lucid dreams were reported subsequent to spontaneous awakening from various stages of sleep as follows: REM sleep 32 times, NREM Stage-1, twice, and during the transition from NREM Stage-2 to REM, once."
Stephen LaBerge, Ph.D. Lucid Dreaming: Psychophysiological Studies of Consciousness during REM Sleep. In Bootzen, R. R., Kihlstrom, J.F. & Schacter, D.L., (Eds.) Sleep and Cognition. Washington, D.C.: American Psychological Association, 1990 (pp. 109-126).
13
"As was mentioned earlier, momentary intrusions of wakefulness occur very commonly during the normal course of REM sleep and it had been proposed by Schwartz and Lefebvre (1973) that lucid dreaming occurs during these micro-awakenings. However, LaBerge et al.'s (1981,1986) data indicates that while lucid dreams do not take place during interludes of wakefulness within REM periods, a minority of lucid dreams (WILDs) are initiated from these moments of transitory arousal, with the WILDs continuing in subsequent undisturbed REM sleep."
14
"The activity of the mental and hyoid muscles, and the H-reflex were examined during nocturnal sleep and daytime naps of narcoleptic and normal subjects.
The continuous, tonic EMG discharges, which were observed in all subjects in the awake state, decreased in parallel with deepening of sleep but disappeared only during the rapid eye movements (REM) period, which occurred at the sleep onset in narcoleptics and late in nocturnal sleep in normal and narcoleptic subjects. During the REM period, only transient, phasic EMG discharges of low voltage were occasionally observed.
The H-reflex also decreased in amplitude when the subjects fell asleep. The degree of its decrement was slight in the drowsy stage and was greater in light and deep sleep. During the REM period which occurred at the sleep onset in narcoleptics and late in nocturnal sleep in normal and narcoleptic subjects, the decrement was most prominent and consistent and the H-reflex would completely disappear."
Yasuo Hishikawa M.D., Noboru Sumitsuji M.D., Kazuo Matsumoto M.D. and Ziro Kaneko M.D. H-reflex and EMG of the mental and hyoid muscles during sleep, with special reference to narcolepsy. Electroencephalography and Clinical Neurophysiology, 18 (5), April 1965, pp. 487-492.
