History of the Study of Dreams - SciTech Connect

Dreaming
Contents
History of the Study of Dreams
The Interpretation of Dreams
The Psychology of Dreams
Dreams, Psychopathology, Psychotherapy
Dreaming and Psychiatric Disorders
Neurobiology of Dreaming
History of the Study of Dreams
ã 2013 Elsevier Inc. All rights reserved.
Glossary
Imagery rehearsal therapy: A treatment program for
the control of nightmares through practice during
waking of pleasant visual images.
Incorporation: Inclusion in the dream report of an
external stimulus.
Mood regulation function: Dream reports
are initially negative in emotion and progressively
become more positive at the end of the
night.
Nightmares: Strongly unpleasant dreams that
awaken the dreamer with full recall of the dream
story.
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Activation-synthesis theory: Hobson and McCarley theory
that dreams are initially random images that acquire
meaning following arousal.
Atonia: Abrupt loss of muscle tone at the onset of rapid eye
movement (REM) sleep.
Dream: A hallucinatory experience during sleep consisting
of visual images related in a story-like structure, which are
accepted as reality at the time.
EMs: Eye movements during a REM period, which vary in
speed and density. These may relate to the visual content of
the dream.
ER
R Cartwright, Rush University Medical Center, Chicago, IL, USA
The Early History of Laboratory Investigation of Dreams
Dreams have been a source of interest throughout human
history. However, much of this literature does not meet the
criteria of being a ‘study.’ This article will cover only investigations that test a hypothesis. Such studies began in the mid1950s when laboratory-monitored sleep proved dreams could
be elicited reliably by awakening sleepers from a specific neurophysiological state known as rapid eye movement (REM)
sleep. This article will cover some highlights of the research
that followed.
Hypothesis: Dreams are Related to REM Sleep
Characteristics
Early sleep studies, and more recent brain imaging work, hypothesized that REM sleep determines the psychological characteristics of dreams. The first such study hypothesized that
body movement within a REM period would disrupt the
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continuity of the reported dream story. REM periods were
divided into those that were continuous and those that were
interrupted by a body movement. The dream reports from
these episodes were judged as being either a continuous narrative or one with an abrupt change to another story. The data
analysis showed that REM periods, free of body movement,
yield continuous dream reports while those with one or more
body movements were associated with reports of unrelated
dreams. This established that REM sleep is typically free of
body movements and that their presence interferes with
dream continuity. This study led to the addition of a chin
muscle monitor, in recognition that loss of muscle tone is a
reliable signal of the onset of REM sleep and thus the likely
presence of dreaming.
Another hypothesis tested whether the reported dream is
related to the type of eye movements (EMs) that precede the
awakening. The EMs were divided into those that were large
(high amplitude) and dense (occurring in bursts) versus those
that were slower and sparser. A significant association was found
between the activity of the EMs and a dream story in which the
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Dreaming | History of the Study of Dreams
Hypothesis: Dreams are Related to Each Other Within
the Night
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Testing the relation of dreams to each other found these were
not obviously similar within the night nor did all the dreams of
a night make up one continuous story. The conclusion was that
dreams are independent stories but with some elements in
common, and that those that were similar were not always
found in reports from adjacent REM periods. Since in only a
few cases was the same theme expressed throughout all the
dreams of a night, it was concluded that, at the level of the
manifest content, dreams are not related to each other. This
raised the question of whether the experimental awakenings
were disrupting a natural continuity of the dreams. Further
study showed the amount of time spent awake for the sleeper
to report their dream was negatively related to the continuity
between that dream and the report from the next REM awakening. The longer the time awake, the less the continuity was.
Although awakenings from REM yielded a report of dreaming 80% of the time, those from nonrapid eye movement
(NREM) sleep yielded widely varied percentages of dream reports. The highest percent was found at sleep onset. More
typically, NREM reports differed in quality from REM reports.
They were described as less imagistic and more thought-like,
less emotional and more pleasant than the highly emotional,
unpleasant reports from REM. To test whether the failure to
find continuity between dreams of the same night was because
the dream theme was set prior to the first REM, the next
investigation collected samples from both NREM and REM
sleep, sampling all Electroencephalography (EEG) stages of
sleep. Sleepers were awakened either 30 or 90 min following
sleep onset by a coin toss. The coin toss was repeated following
each report to determine the timing of the next awakening.
This resulted in 6–9 reports each night in random sequences of
various sleep stages. The reports were examined for repeated
images or themes in the manifest content. Sometimes, the
initial report was from a NREM stage before any REM had
occurred. Repeated elements were found in different sequences
of sleep stages. Testing continuity of the sleeping mind using
this random awakening schedule presents a real difficulty:
repeated elements may be present but missed if the random
protocol skipped a time when reports were most connected.
In conclusion, there were nights with little or no repeated elements and others when these were plentiful in both NREM and
REM sleep. During nights when these were frequent, they were
also the most vivid and memorable of the reported dream but
were embedded into distinctly independent contexts, suggesting
that they were driven by intense preoccupations (possibly preconscious day residues), which then interfaced in sleep with
ongoing unconscious (latent) dream thoughts. The conclusion
was that there is an interaction of preconscious and unconscious
streams of thought throughout sleep but that the methods used
to analyze dreams were not appropriate to identify these.
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dreamer was engaged in some activity. As per reports following
sparse EMs, the dreamer was passive or was ‘just observing.’
Studies correlating REM characteristics and dream features
waned following the publication of the Hobson and McCarley
activation-synthesis theory of dream construction. These neuroscientists had located the cells involved in initiating REM
sleep to be in the pons, an area at the base of the brain. They
argued that as this excitation traveled upward through the
occipital cortex, random visual images were stimulated. These
acquired meaning only during arousal when the higher brain
areas attempt to make sense of these inherently meaningless
images. Later, brain imaging studies, using positron emission
tomography (PET) scans and functional magnetic resonance
imaging (fMRI), identified patterns of brain areas that are more
or less active in REM sleep than in waking, or in nonrapid eye
movement (NREM) sleep and the relation of these to the
known function of these brain areas. These studies added
specificity to the description of REM as a highly activated
brain state. Finding strong activity in the limbic and paralimbic
cortex (the amygdala, hypothalamus, the anterior cingulate)
supports that dreams are more likely to involve negative emotions. The deactivation of the prefrontal cortex accounts for the
difficulty remembering dreams and the weakening of reality
testing (accepting the dream as if real). Dream reports collected
during these imaging studies verified that dreams were being
experienced during a specific pattern of increased and decreased brain activity in healthy persons but these varied in
different clinical samples. This moved the dream interpretation
question back from being a waking afterthought to being due
to the particular brain areas active in the REM state.
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Hypothesis: Dream Images are Internally Generated
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Early experiments attempted to test whether the images reported
in dreams could be influenced by applying a variety of external
stimuli during an ongoing REM episode. They first used an
auditory tone, a flashing light, and a spray of water, followed
by a doorbell to awaken the sleeper to report their experience.
None of these stimuli was ‘markedly effective’ in modifying the
ongoing dream. Another study used auditory stimuli of spoken
proper names, two of which were emotionally salient and two
were neutral. The finding was that half of the dream reports
showed some effect although this was not by a direct inclusion
of the names but by a similarity in sound of a word in the report
to the stimulus name (via assonance). Familiar names, their
own or those of ex-girlfriends, were more likely to have an effect
on the dream content than neutral names. The finding that
emotional stimuli have more effect on dream content than
those neutral in tone has been a repeated finding.
To test whether the auditory stimuli had more effect on
dreams than the visual, because the receptor organs (ears)
were open in sleep while the eyes were not, volunteers were
tested while sleeping with their eyes taped open. Once REM
was identified, an experimenter held up an object in front of
the sleeper’s eyes, before they were awakened to give a dream
report. Judges attempted to match these reports to the stimulus
object. As they were not able do this at a rate better than
chance, the conclusion was that dream images are internally
generated and only on rare occasions are external stimuli responsible for some element of a dream.
Hypothesis: Dreams Relate to the Presleep
Waking State
The findings of the TV study reported above pushed the question of how dreams are constructed back still earlier to examine
Dreaming | History of the Study of Dreams
interactions. On the final night, Night 5, the recall rate returned
to the baseline control level and the number of dreams with two
characters was significantly higher than on the control night.
In summary, the findings of an immediate increase in failure to recall from REM awakenings and lack of any direct
incorporation into dreams of the arousing movie suggested
an inhibiting effect possibly related to the presleep interactions
with the laboratory personnel, two attractive female technicians, with whom they had some bodily contact during the
application of the electrodes. This appears to have raised anxiety
about having, or reporting, explicit dreams leading to both a
dampening of recall and increased number of dreams with only
one character. The conclusion was that although the sexual
movie produced an immediate physiological arousal response
in waking, it was inhibited from direct expression in sleep on
Night 2. On the following Night 3, the number of symbolic
sexual words in the dream reports hit the highest peak. Over the
next three nights, there was a gradual return to the baseline recall
rate. The laboratory situation appeared to have a powerful inhibiting effect on the drive aroused by watching the movie.
Finding that the planned effect of experimental stimuli
often had a minimal effect and that the social context may
have a more powerful, unanticipated effect on dream content,
there was a shift in research strategy toward more naturalistic
studies. Dreams following natural disasters, such as the 9/11
terrorist attack, the holocaust, bereavement, divorce, kidnapping, rape, and living under missile attacks, have all been
studied. The landmark study of this kind chose an inherently
emotion arousing event, elective surgery, to study the effect on
dreams. Patients were recorded for four nights before and three
nights after surgery. Rating scales were constructed for analyzing the dreams including degree of recall, anxiety, and involvement. The general conclusion was that the surgeries meant
different things to different patients. The initial dreams never
dealt with the surgery directly but as has been seen before there
were many transformations to represent this event symbolically. Most apparent was that the dreams demonstrated the
participant’s attempts to integrate the present stressful event
into their individual adaptive strategies that had worked for
them in the past. If this has a learning effect on future coping,
longer follow up would be needed.
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the influence of the emotional state of the participants before
they fell asleep. It was clear that there was also a need for more
subtle and more systematic methods to measure dream content. The most comprehensive and influential of the scales
developed were those of Hall and Van de Castle. These allowed
studies to compare dream reports of various groups on standardized measures. Differences were found between the
dreams of men and women, older and younger age groups,
ethnic groups, and many clinical groups such as alcoholics and
nondrinkers. Studies of the relation between the prior waking
psychological state and the dreams of the night began to use
the Hall and Van de Castle scales for standardizing the dream
content and various personality tests for measuring waking
traits and states. The presleep emotional state of the volunteer
was then manipulated using stimuli chosen to be emotion
invoking or bland, and reports from the following dreams
were analyzed using the new content scales. One study used
two episodes of a TV series, one very violent and the other a
comedy. The order of these was counterbalanced on two sleep
nights. Reports were collected from both REM and NREM sleep
episodes to explore the differences in the influence of these
movies on the different sleep stages, as well as the relation to
the waking personality characteristics. The aggressive film produced longer and more imaginative, more vivid, and emotional REM reports than did the comedy movie. However,
these film differences were not found between the reports
collected from NREM sleep. The correlation of dream characteristics and the waking personality tests showed an ‘extremely
consistent pattern of correlations between the clinically oriented scales and dream-like features of the reports.’ The imaginativeness of the person in waking was highly correlated with
that aspect of the dream reports. There were no significant
direct incorporations of either film into the sleep reports.
Why the aggressive film had a clear impact on REM reports
but not on those from NREM and why, despite the increase in
vivid, imaginative, emotional REM dreams after the violent
film, were the dreams not more violent or unpleasant? The
explanation offered was that the violent film had a general
effect and not a specific one, and that the general emotional
arousal stimulated the viewers’ personal emotional memories
to be displayed during REM sleep.
To focus the waking attention to a specific drive, the next
study included a physiological measure of sexual arousal during the exposure to a pornographic film. This study examined
the effects of this on the dreams of adult men over five nights of
REM collections. The first night was a control to assess the
baseline rate of sexual dreams. The following day, the participants wore a penile strain gauge to measure their response to
the movie shown before their second night. The dream reports
were analyzed using the Hall and Van de Castle norms for the
frequency of common words in the dream reports of a similar
sample of adult men. Judges first rated these words for symbolic sexual reference, for example, balls, nuts, shaft, and fountain. The judges agreed on ten words as having symbolic sexual
meaning and ten others were chosen to refer to the laboratory
setting. There was a marked increase in the symbolic words in
the dream reports over the rate expected from the norms. That
this might represent a latent response to the sexual film was
supported by a significant increase in ‘No recall’ reports on
Night 2, and an increase in number of dreams with one character, indicating a possible suppression response to two-person
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Hypothesis: Dreams Effect Postsleep Psychological
Functioning
Studies of the effect of dreams on changing the waking mood
have examined both healthy persons and those with clinical
diagnoses. One study of a healthy, high functioning sample
used the Profile of Mood States (POMS) test before and after
sleep for two nights with REM interruptions for collecting
dreams on the second night. The sleepers rated the emotional
quality of each dream immediately following their report as
positive/pleasant, neutral, or negative/unpleasant. The sample
was divided on the presleep mood score into those who had
little or no elevation on the Depression Mood Scale and those
who had a mild elevation of this negative mood. The Not
Depressed (ND) group had twice as many positive dreams as
negative and the Mildly Depressed (MD) had an equal number
of positive and negative dreams. To test whether dreams regulate
mood within sleep, the average ratings of dream affect in the first
Dreaming | History of the Study of Dreams
Hypothesis: Dreams Differ in Psychiatric Patients
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The ‘naturalistic’ studies, particularly of sleep during or after
traumatic events, brought attention to the study of nightmares.
These fear-inducing dreams lead to an interruption of sleep, an
awakening with full recall of the dream. These are the most
disturbing symptom of posttraumatic stress disorder (PTSD),
the most long lasting symptom and the one most difficult to
treat. The PTSD diagnosis includes not only distressing dreams
but in some exact replications of the traumatic event. Treatments that train patients to control their dreams have become
the behavioral treatment of choice. To test whether dreamers
are capable of controlling their dreams, Imagery Rehearsal
Therapy, a brief clinical program, was developed. This begins
by training nightmare patients to rehearse a positive image of
their choice during waking. Next step is to write out their
nightmare but to change the ending to one they prefer. That
this trains nightmare control is being reported in some studies
based on self-report.
Dreams have also been studied in major depression since
these patients show abnormalities of REM sleep and dream
reports that are both brief and bland in feeling when the
depression is severe. Moderate depression is characterized by
dreams with negative feelings, which fail to reduce, in fact
increase, in frequency within the night. Those whose withinsleep pattern of dream affect resembles that of healthy samples,
with decreasing negative and increasing positive dreams within
the night, are more likely to remit without treatment within a
year. This finding has been confirmed in several studies leading
to the first verified function of dreams: dreaming performs a
mood regulatory function.
Partly, this is due to recent studies of patients with brain
injuries, seizure disorders, and psychosurgeries who report
changes in their dreaming. Solms reported almost 1000 cases
experiencing a cessation of dreaming following a focal forebrain lesion. Many of these were confirmed as ‘dreamless’ by
the REM awakening method. In these cases, the pontine brain
stem was completely spared and REM sleep was intact. Further,
he found that dreaming can be initiated by a forebrain mechanism independent of the REM state in those with nocturnal
seizures occurring in NREM sleep, which are experienced as
nightmares. Comparing a large sample of patients who
reported changes in their dream experience and a healthy
control sample, Solms identified the brain areas that had
been damaged or surgically removed and the patients’ experience of changes in their dreams, to map the structures responsible for specific characteristics of dreams, for example, the
presence of color or of people. This led him to conclude that
dreaming and REM sleep are controlled by different mechanisms; with REM initiated from the pons and dreaming from
the forebrain. What is common is that dreaming occurs not
only in sleep when the brain is highly activated as it is in REM
but also in the transitions between waking and sleep; at sleep
onset in NREM and at the end of the sleep cycle just prior to
waking. This allows clinical intervention for control of nightmares, to target sleep onset.
The other major conclusion from this review is that dreams
are strongly influenced by the waking emotional state, which is
not expressed directly but in sensory images drawn from associated memory networks. These will be displayed in a sequence
of dreams that function to down-regulate negative mood.
Given these studies, it should be possible to estimate the health
of this function by collecting only two samples: the first from
sleep onset and the second from the end of sleep. This would
avoid disrupting the sleep with REM awakenings and minimize
the laboratory effect.
ER
half of the night was compared to the average of those in the
second. The ND had more positive than negative dreams in
both halves. The MD had a high proportion of negative dreams
in the first half-night, with a marked decrease in the last half and
the opposite pattern for positive dreams; with few at the beginning of the night and a high proportion at the end of the night.
The conclusion that sleep generally improves morning
mood was confirmed by a lower depression score following
both nights. Whether this effect is related to the intervening
dreams was supported by the finding that the affect in first
dreams of the night was significantly correlated to the previous
waking mood. Even when this mood was only mildly unhappy, negative dreams dominate in the first dream reports
and then decrease in the second half-night. The natural sequence appears to be that the emotional state before sleep is
continued into sleep onset, stimulating a network of memories
associated with similar feeling. The varied dream scenarios or
‘contexts’ appear to dissipate the negative mood, which in turn
accounts for the improved morning mood in healthy persons.
If this is a natural function in well-adjusted adults, do dreams
display dysfunctions in those not emotionally fit?
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The Future of Dream Research
As reviewed here, studies of the last 60 years have freed dreams
of being seen as meaningless accompaniments of REM sleep.
See also: Critical Theoretical and Practical Issues: Future of
Sleep Research; The Function of Sleep; Dreaming: Dreaming and
Psychiatric Disorders; Dreams, Psychopathology, Psychotherapy;
Neurobiology of Dreaming; The Interpretation of Dreams; The
Psychology of Dreams; Instrumentation and Methodology:
Neuroimaging and Sleep; Nocturnal Penile Tumescence; Psychiatric
Associations of Sleep Loss/Deprivation: Changes in Affect;
Personality and Psychopathic Changes
Further Reading
Cartwright R (1990) A network model of dreams. In: Bootzin RR, Kihlstrom JF, and
Schacter DL (eds.) Sleep and Cognition, pp. 179–189. Washington, DC: American
Psychological Association.
Cartwright R (1991) Dreams that work: The relation of dream incorporation to adaptation
to stressful events. Dreaming 1: 3–9.
Cartwright R (2005) Dreaming as a mood regulation system. In: Kryger M, Roth T, and
Dement W (eds.) Principles and Practice of Sleep Medicine, 4th edn., pp. 565–572.
Philadelphia, PA: Elsevier Saunders.
Cartwright R (2010) The Twenty-four Hour Mind: The Role of Sleep and Dreaming in
Our Emotional Lives. New York, NY: Oxford University Press.
Cartwright R, Bernick N, Borowitz G, and Kling A (1969) The effects of an erotic movie
on the sleep and dreams of young men. Archives of General Psychiatry
20: 262–271.
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Dreaming | History of the Study of Dreams
Krakow B, Hollifeld M, and Schrader R (2000) A controlled study of imagery rehearsal
for chronic nightmares in sexual assault survivors with PTSD: A preliminary
report. Journal of Traumatic Stress 13: 589–609.
Kramer M (1993) The selective mood regulatory function of dreaming: An update
and revision. In: Moffitt A, Kramer M, and Hoffman R (eds.) The Functions of
Dreaming, pp. 139–195. Albany, NY: State University of New York Press.
Lavie P and Kaminer H (1991) Dreams that poison sleep: Dreaming in holocaust
survivors. Dreaming 1: 11–21.
Nofzinger EA, Mintun MA, Wiseman M, Kupfer D, and Moore RY (1997) Forebrain
activation in REM sleep: An FDG PET study. Brain Research 770: 192–201.
Solms M (1997) The Neuropsychology of Dreams: A Clinico-Anatomical Study.
Mahwah, NJ: Lawrence Erlbaum Associates.
Solms M (2003) Dreaming and REM sleep are controlled by different brain
mechanisms. In: Pace-Schott E, Solms M, Blagrove M, and Harnad S (eds.)
Sleep and Dreaming: Scientific Advances and Reconsiderations, pp. 51–58.
New York, NY: Cambridge University Press.
Stickgold R (2003) Memory, cognition and dreams. In: Maquet P, Smith C, and Stickgold R
(eds.) Sleep and Brain Plasticity, pp. 17–39. New York, NY: Oxford University Press.
Strauch I and Meier B (1996) In Search of Dreams: Results of Experimental Dream
Research. Albany, NY: State University of New York Press.
Witkin HA and Lewis HB (1967) Experimental Studies of Dreaming. New York, NY:
Random House.
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Dement W and Kleitman N (1957) The relation of eye movement during sleep to dream
activity: An objective method for the study of dreaming. Journal of Experimental
Psychology 53: 330–346.
Dement W and Wolpert E (1958) Relationships in the manifest content of dreams
occurring on the same night. The Journal of Nervous and Mental Disease
126: 568–578.
Ellman SJ and Antrobus JS (1991) The Mind in Sleep: Psychology and
Psychophysiology, 2nd edn. New York, NY: John Wiley & Sons.
Foulkes D (1985) Dreaming: A Cognitive-Psychological Analysis. Hinsdale, NJ:
Lawrence Erlbaum Associates.
Foulkes D and Vogel G (1965) Mental activity at sleep onset. Journal of Abnormal
Psychology 70: 231–243.
Hall CS and Van de Castle R (1966) The Content Analysis of Dreams. New York, NY:
Appleton-Century-Crofts.
Hartmann E (2002) Dreaming. In: Lee-Chiong T, Sateia MJ, and Carskadon MA (eds.)
Sleep Medicine, pp. 93–98. Philadelphia, PA: Hanley & Balfus.
Hobson JA and McCarley RW (1997) The brain as a dream-state generator:
An activation-synthesis hypothesis of the dream process. The American Journal of
Psychiatry 134: 1335–1348.
Koulack D (1993) Dreams and adaptation to contemporary stress. In: Moffitt A,
Kramer M, and Hoffman R (eds.) The Functions of Dreaming, pp. 321–340.
Albany, NY: State University of New York Press.
Sleepwalking
V Jain, Stanford Sleep Medicine Center, Redwood City, CA, USA
Published by Elsevier Inc.
Parasomnias: Undesirable movements and behaviors that
occur during entry into sleep, within sleep, or in the setting
of arousals from sleep.
Sleep diaries: Records kept by the patient or family
member/partner that indicate sleep onset and offset
times, including naps and awakenings overnight; these
Description
also published a twin study that reported a six-time greater
concordance for sleepwalking among monozygotic twins
than in dizygotic twins.
Factors such as sleep deprivation, fever, head injury, alcohol
abuse, hyperthyroidism, and other conditions have also been
shown to induce sleepwalking. The use of certain medications,
including lithium, tricyclic antidepressants (TCAs), phenothiazines, zolpidem, and other benzodiazepine receptor agonists,
can also precipitate these events. Studies have also shown that
sleep-disordered breathing in children, that is, obstructive
sleep apnea (OSA), may trigger sleepwalking due to the frequent arousals associated with respiratory events. Effective
treatment of OSA may reduce the frequency of sleepwalking
episodes in some patients.
Overall, sleepwalking has been reported to have a 2%
prevalence in the general population. Sleepwalking tends to
be more prevalent in childhood, peaking around age 8, and
generally resolves with puberty although episodes have been
described in adults. While de novo sleepwalking can occur in
adulthood, many adults who sleepwalk first exhibited sleepwalking behavior in childhood. The persistence of sleepwalking into adulthood has been associated with underlying
psychopathology in a significant number of patients.
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Sleepwalking is characterized by complex behaviors that are
typically initiated during arousals from sleep and result in
ambulation. The activity can vary from simple events such as
sitting up in bed to more complex movements such as walking
or even ‘bolting’ from the room. These episodes can last from a
few seconds to several minutes long. Patients are generally
difficult to arouse during these periods, and if they are able to
be awakened, patients are often in a confused state. Many
patients typically have their eyes open and have a ‘glassyeyed’ appearance during sleepwalking episodes. As these events
typically occur because of arousals from slow-wave sleep, they
generally occur during the first half of the sleep period.
While some patients may have little memory of the event,
most patients generally have no memory of the event the following morning. Patients may be able to recall emotions or impressions from the event. Symptoms of tachycardia, sweating, or the
expression of fear is generally not displayed in patients during an
episode. The absence of autonomic symptoms and screaming is
what can differentiate a sleepwalking episode from sleep terrors.
Sleepwalking is a subset of a larger group of parasomnias.
Parasomnias are undesirable movements and behaviors that
occur during entry into sleep, during sleep, or with arousals
from sleep. Parasomnias are subdivided into several categories:
(1) disorders of arousal from non-REM sleep, (2) parasomnias
associated with REM sleep, and (3) other parasomnias.
The disorders of arousal include confusional arousals, sleepwalking, and sleep terrors. The disorders of arousal tend to
occur in stage N3 sleep and therefore typically occur in the
first third of the night.
data are often helpful in determining whether
parasomnia episodes are triggered by relative sleep
deprivation.
Sleepwalking: Complex behaviors usually initiated during
arousals from sleep culminating in ambulation during an
altered state of consciousness and impaired judgment; also
referred to as somnambulism.
ER
Glossary
Risk Factors
There are a number of factors that may predispose a patient to
sleepwalking. There is a strong genetic influence in the development of sleepwalking. Generally, if one or both parents have
had a history of sleepwalking, the child is at a significantly
increased risk of developing sleepwalking episodes as well. The
Finnish Twin Cohort study published by Hublin et al. reported
a concordance rate of 55% for monozygotic and 35% for
dizygotic twins for sleepwalking in childhood. Bakwin et al.
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Diagnosis and Differential Diagnosis
The most important initial approach to diagnosing sleepwalking is to obtain a careful and detailed history from the patient
and their bed partner, parent, or caregiver. Information regarding the frequency, timing, and duration of the episodes should
be obtained. It may be helpful to have patients keep a sleep
diary to document this information. Detailed descriptions of
any motor behavior should be obtained and the patient should
be questioned about sensory symptoms. The clinician should
pay particular attention to the patient’s past medical history,
family history, and medication list to look for any precipitating
factors outlined above. If the patient relays a history of associated snoring or apnea, they should also be evaluated for
underlying sleep-disordered breathing.
While not required for a diagnosis, overnight polysomnography (PSG) can also be a valuable tool in the evaluation of
sleepwalking. Although rare, the occurrence of a complex
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Descriptions of Parasomnias | Sleepwalking
schedules, and unfamiliar sleep environments can increase sleepwalking episodes. If inciting agents are noted on the medication
list, the precipitating agent should be avoided and the patient
should be provided with a therapeutic alternative. If sleepwalking
activity remains problematic, pharmacologic therapy with benzodiazepines, TCAs, and selective serotonin reuptake inhibitors
may provide benefit. Clonazepam at a dose of 0.5–2.0 mg administered at bedtime has been successful at controlling sleepwalking activity.
Conclusion
ER
In conclusion, sleepwalking is a common parasomnia that is
most prevalent in children. There is a strong genetic influence,
and many factors can precipitate sleepwalking episodes. The
diagnosis can be obtained from a careful and detailed history.
In more complicated cases, PSG may be used. Clinical suspicion
of any underlying etiology warrants appropriate evaluation and
treatment. The management of sleepwalking is typically straightforward with reassurance and counseling on safety precautions.
Finally, in refractory cases, pharmacotherapy may be warranted.
See also: Descriptions of Parasomnias: Confusional Arousals;
Parasomnias in Children; Sleep Terrors.
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behavior during PSG can support the diagnosis. While not
pathognomonic for sleepwalking, several PSG findings have
been thought to be associated with disorders of arousals.
Patients with sleepwalking have been found to have an
increased number of arousals from slow-wave sleep when
compared to matched controls. It has also been suggested that
patients with a higher percentage of slow-wave sleep are at
higher risk for disorders of arousals. However, studies of sleepwalkers have revealed that many have the same if not lower
slow-wave sleep activity when compared to matched controls.
Also, arousals during slow-wave sleep can be seen in disorders
other than sleepwalking such as OSA and periodic limb movements in sleep (PLMS). Hypersynchronous delta (HSD) activity
has been documented just before sleepwalking episodes in several studies. HSD waves consist of two or more high amplitude
delta frequency waves that precede an arousal or complex behavior during sleep. Although sleepwalkers have been found to
have higher ratios of HSD during slow-wave sleep, this finding
has not been confirmed in more recent studies. Finally, as sleepdisordered breathing has been postulated as a possible trigger
for sleepwalking, evidence of OSA on PSG should prompt treatment with nasal continuous positive airway pressure (nCPAP),
as successful treatment has been reported to decrease or eliminate the occurrence of sleepwalking.
The differential diagnosis of sleepwalking includes other
NREM parasomnias such as confusional arousals and night
terrors and other sleep disorders, including nightmare disorders, rapid eye movement sleep behavior disorder (RBD), nocturnal seizure activity, epileptic events, and sleep-related panic
attacks. Sleepwalking can be differentiated from sleep terrors
by the lack of autonomic hyperactivity and loud scream during
nocturnal episodes. Nightmare disorder and RBD both occur
within REM sleep and are more common in the second half of
the night. Also, children who are aroused from a nightmare
generally become alert quickly and may often provide a detailed description of their dream content. If there is concern
regarding epileptic activity, nocturnal PSG should be
performed with an expanded seizure montage. Patients with
sleep-related panic attacks typically develop autonomic activation following arousal from sleep and lack the confusion and
amnesia seen in sleepwalkers.
Further Reading
AASM (2005) International Classification of Sleep Disorders: Diagnostic and Coding
Manual, 2nd edn. Westchester, IL: American Academy of Sleep Medicine.
Avidan AY and Kaplish N (2011) The parasomnias: Epidemiology, clinical features and
diagnostic approach. Clinics in Chest Medicine 31: 353–370.
Bakwin H (1970) Sleepwalking in twins. The Lancet 2: 466–467.
Barabas G, Ferrari M, and Matthews WS (1983) Childhood migraine and
somnambulism. Neurology 33: 948–949.
Berry R (2012) Fundamentals of Sleep Medicine, pp. 567–592. Philadelphia PA:
Elsevier Saunders.
Broughton RJ (1968) Sleep disorders: Disorders of arousal? Enuresis, somnambulism,
and nightmares occur in confusional states of arousal, not in "dreaming sleep".
Science 159: 1070–1078.
Broughton R (2000) NREM parasomnias. In: Kryger MHRT and Dement WC (eds.)
Principles and Practice of Sleep Medicine, pp. 693–706. Philadelphia, PA: W.B.
Saunders.
Chokroverty SHW and Walters AS (2003) An approach to the patient with movement
disorders during sleep and classification. In: Chokroverty SHW and Walters AS
(eds.) Sleep and Movement Disorders, pp. 201–218. Philadelphia, PA:
Butterworth-Heinemann.
Espa F, Dauvilliers Y, Ondze B, Billiard M, and Besset A (2002) Arousal reactions in
sleepwalking and night terrors in adults: The role of respiratory events. Sleep
25: 871–875.
Goodwin JL, Kaemingk KL, Fregosi RF, et al. (2004) Parasomnias and sleep
disordered breathing in Caucasian and Hispanic children – the Tucson children’s
assessment of sleep apnea study. BMC Medicine 2: 14.
Guilleminault C, Palombini L, Pelayo R, and Chervin RD (2003) Sleepwalking and
sleep terrors in prepubertal children: What triggers them? Pediatrics
111: e17–e25.
Hublin C, Kaprio J, Partinen M, et al. (1997) Prevalence and genetics of sleepwalking:
A population-based twin study. Neurology 48: 177–181.
Kales JD, Kales A, Soldatos CR, Chamberlin K, and Martin ED (1979) Sleepwalking and
night terrors related to febrile illness. The American Journal of Psychiatry
136: 1214–1215.
Kales A, Soldatos CR, Bixler EO, et al. (1980) Hereditary factors in sleepwalking and
night terrors. The British Journal of Psychiatry 137: 111–118.
SE
EL
Management
Management of sleepwalking should focus on both attempting to
eliminate the occurrence of the events and mitigating the adverse
effects of a potential episode. Patients with other sleep, medical,
or psychiatric disorders should obtain appropriate treatment for
the underlying disorder. Next, patients should be provided reassurance and counseling regarding safety precautions in the home.
Patients and their parents, bed partners, or caregivers should be
reassured that many arousal disorders decline in frequency, as a
child enters adolescence. The clinician should ensure that
counseling regarding environmental protection is provided.
Safety measures include locks on doors and windows, sleeping
on the first level of the home, gates across stairs, removing sharp
objects from the bedroom, avoiding bunk beds, and placing
padding or mattresses next to the bed. Emphasis should also be
placed on sleep hygiene, as sleep deprivation, irregular sleep
203
204
Descriptions of Parasomnias | Sleepwalking
Pesikoff RB and Davis PC (1971) Treatment of pavor nocturnus and somnambulism in
children. The American Journal of Psychiatry 128: 778–781.
Robinson A and Guilleminault C (2003) Disorders of arousal. In: Chokroverty SHW and
Walters AS (eds.) Sleep and Movement Disorders, pp. 265–272. Philadelphia, PA:
Butterworth-Heinemann.
Rosen GM, Ferber R, and Mahowald MW (1996) Evaluation of parasomnias in children.
Child and Adolescent Clinics of North America 5: 601–616.
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Laberge L, Tremblay RE, Vitaro F, and Montplaisir J (2000) Development of
parasomnias from childhood to early adolescence. Pediatrics 106: 67–74.
Mahowald M (2002) Arousal and sleep-wake transition parasomnias.
In: Lee-Chiong TLSM and Carskadon MA (eds.) Sleep Medicine, pp. 207–213.
Philadelphia, PA: Hanley and Belfus.
Mindell JA and Owens J (2003) Sleepwalking and sleep terrors. A Clinical Guide to
Pediatric Sleep. Philadelphia, PA: Lipincott Williams &Wilkins.
Special Conditions, Disorders, and Clinical Issues of SRMD
Contents
Gender Differences in Sleep-Related Movement Disorders
Sleep-Related Movement Disorders in Children
Age-Related Changes in PLMS Characteristics of RLS Patients
Medication Effects and Sleep-Related Movement Disorders
Restless Legs Syndrome in Internal Medicine
Impact of Psychiatric Disorders on Sleep-Related Movement Disorders
Gender Differences in Sleep-Related Movement Disorders
ã 2013 Elsevier Inc. All rights reserved.
Glossary
more than 15 times per hour in adults (or more than five
times per hour in children) and is associated with sleep
disturbance and/or daytime fatigue or sleepiness.
Sleep-disordered breathing (SDB): This describes a group
of disorders characterized by abnormalities of respiratory
pattern (pauses in breathing) or the quantity of ventilation
during sleep.
Restless Legs Syndrome
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Clinical Features
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Periodic limb movements (PLMs): Stereotyped
and repetitive limb movements that occur during
sleep.
Periodic limb movement disorder (PLMD): A sleep
disorder characterized by stereotyped and repetitive
limb movements that occur during sleep at the rate of
ER
B Phillips, University of KY College of Medicine, Lexington, KY, USA; UK GSH Hospital, Lexington, KY, USA
Restless legs syndrome (RLS) is a sleep-related movement disorder whose cardinal feature is unpleasant leg sensations, typically occurring at night, that interfere with sleep. The sensation
is probably most aptly described as a powerful urge to move
the legs; it is rarely described as painful, and the possibility
of neuropathy should be considered when the discomfort
presents primarily as pain. There is a circadian variation in
symptoms, with greatest intensity typically occurring between
10 p.m. and 2 a.m. Symptoms are worse at rest and improve
with movement or stimulation, including walking, rubbing,
and stretching. The distressing sensations most typically involve the legs, but can also occur in the arms. Because of the
nature and timing of RLS symptoms, patients with RLS may
present with sleep-onset insomnia.
Diagnosis
The diagnosis of RLS is made by history and physical examination based on criteria listed in Table 1.
Thus, the diagnosis is based on subjective criteria alone, and
polysomnography (PSG) is not generally necessary. The
Encyclopedia of Sleep
http://dx.doi.org/10.1016/B978-0-12-378610-4.00404-6
specificity of these criteria is not ideal, but careful application
of the first four features, accompanied by a physical examination (to rule out neuropathy and vascular disease), is fairly
specific for RLS. The differential diagnosis includes cramps,
positional discomfort, vascular leg disease, and neuropathy.
Adding response to dopaminergic medication to the essential
criteria improves diagnostic accuracy.
Epidemiology
In population-based surveys, typically conducted by phone, the
prevalence of any degree of RLS symptoms is estimated to be
somewhere between 10% and 15% for all adults, with lower rates
in the young and higher in the elderly. However, the prevalence
of RLS varies considerably with different criteria for frequency
and severity. For example, in the restless legs syndrome prevalence and impact Restless Legs Epidemiology Symptoms and
Treatment (REST) study, RLS symptoms were endorsed by 7.2%
of the survey population. However, symptoms occurring at least
twice per week were reported by only 5% of the subjects and were
moderately or severely distressing in only 2.7%.
The rate of RLS may be lower in Asian than in European
populations, but the prevalence in African Americans is similar
to that of Caucasians.
109
Table 1
Special Conditions, Disorders, and Clinical Issues of SRMD | Gender Differences in Sleep-Related Movement Disorders
Diagnostic criteria for RLS in adults
A. The patient reports an urge to move the legs, usually accompanied or
caused by uncomfortable and unpleasant sensations in the legs.
B. The urge to move or the unpleasant sensations begin or worsen
during periods of rest or inactivity such as lying or sitting.
C. The urge to move or the unpleasant sensations are partially or totally
relieved by movement, such as walking and stretching, or at least as
long as the activity continues.
D. The urge to move or the unpleasant sensations are worse, or only
occur, in the evening or night.
E. The condition is not better explained by another current sleep
disorder, medical or neurological disorder, mental disorder,
medication use, or substance use disorder.
From American Academy of Sleep Medicine (2005) International Classification of
Sleep Disorders: Diagnostic and Coding Manual, 2nd edn., p. 180. Westchester, IL:
American Academy of Sleep Medicine.
Gender Differences for RLS
Associative, Predisposing, and Precipitating Factors
Two recent genome-wide association studies have reported
positive association with sequence variants in or around specific genes on chromosomes 6p, 2p, and 15q and having
symptoms of RLS (and periodic limb movements). Serum
ferritin levels are lower in those with the genetic variant that
predisposes to RLS, which supports the hypothesis that iron
depletion or dysfunction is somehow involved in the pathogenesis of the disease. Dopamine deficiency or dysfunction is
also in the pathophysiology of RLS, and one unifying hypothesis is that impairment of dopamine transport or function in
the central nervous system due to reduced iron may contribute
to the development of this disorder.
Primary RLS occurs without a known predisposing or exacerbating condition, is more likely to have earlier age of onset,
and is likely to be familial. RLS can also be ‘secondary’ to
another condition, including especially iron deficiency, pregnancy, and renal failure.
A large group of conditions has now been reported to be
associated with RLS. Many of these conditions and disorders
also lack objective diagnostic criteria, such as attention deficit
hyperactivity disorder, depression, and fibromyalgia, and
many occur with increased frequency in women.
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RLS affects women disproportionately. A consistent finding in
the literature about RLS is that women are 1.5–2 times as likely
as men are to report RLS symptoms. Studies in both children
and adolescents have demonstrated that this difference does
not usually develop until the second or third decade of life.
However, after the third decade, women are about twice as
likely as men to endorse RLS symptoms, and the likelihood
of having RLS may be related to pregnancy. Pregnancy is an
important risk factor for RLS, both during the pregnancy and in
subsequent years. About a fourth of pregnant women experience RLS symptoms, which typically peak in severity in the
third trimester and resolve promptly after delivery. Lower hemoglobin, mean corpuscular volumes, and serum folate levels
appear to be risk factors for RLS in pregnancy. With aging, the
risk of RLS is fairly level for men, but it increases for women,
proportionate to parity. In one study, nulliparous women had
the same risk for RLS as did men up to the age of 64. However,
for women who had borne children, the risk of RLS increased
with the number of children. A woman with one child had
twice the risk of RLS as a nulliparous woman and the risk
increased with additional children. Indeed, a recent publication by Pantaleo et al. indicated that pregnancy accounts for
almost all of the gender differences reported in overall RLS
prevalence.
The gender difference in RLS symptoms appears to be
present for both primary and secondary RLS. In a large crosssectional study of patients with end-stage renal disease (ESRD),
women were much more likely than men were to endorse RLS
symptoms. Other associated factors for RLS in ESRD include
lower hemoglobin, worse subjective and objective sleep quality, excessive daytime sleepiness, use of sleeping pills, depressive symptoms, and higher risk of both obstructive sleep apnea
and hypertension.
RLS is frequently reported to occur with antidepressant use.
It appears likely that the association between RLS and antidepressant use varies by gender and by type of antidepressant.
Indeed, antidepressants were more strongly associated with
RLS for men than for women in one study. But analyses of
individual agents showed that fluoxetine was more strongly
associated with RLS in women than in men, whereas use of
paroxetine, citalopram, and amitriptyline was more likely
to be associated with RLS symptoms in men.
Augmentation (worsening of symptoms despite treatment)
occurs in a large percentage of patients treated with levodopa.
Data on the prevalence of augmentation with dopamine agonists are still scant, but this phenomenon has been documented to occur with these agents. One study reported a prevalence
rate of about 12% with dopamine agonists, with low ferritin
being the primary associated risk. In that study, there were no
gender differences in the rate of augmentation.
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110
Complications and consequences
Individuals with RLS are at increased risk for mood disturbance, according to cross-sectional studies. This is not necessarily a causal relationship; mood disturbance could contribute
to endorsement of RLS symptoms. Like RLS, depression occurs
with increased frequency in women compared to men and could
partly account for the increased prevalence of RLS symptoms in
women. The effects of RLS symptoms on daytime function are
not clear. RLS has variously been reported to be associated with
daytime sleepiness as well as not to impair daytime sleepiness
and alertness. It does, however, appear to adversely affect quality
and quantity of nocturnal sleep. RLS appears to be associated
with many significant medical conditions and may be a marker
for poor overall health. Indeed, one study has reported an increased risk of death in individuals with RLS.
Management
Nonpharmacologic treatment
Elimination of factors that may cause or contribute to RLS
may make a difference. Several medications have been linked
to both RLS and periodic limb movements, and the data
are particularly strong for the association between RLS and
antidepressants. Lifestyle relates to RLS symptoms: increased
Special Conditions, Disorders, and Clinical Issues of SRMD | Gender Differences in Sleep-Related Movement Disorders
Pharmacologic treatment
RLS and periodic limb movements frequently coexist, which
has resulted in much confusion about periodic limb movements. Periodic limb movements of sleep (PLMS), originally
called nocturnal myoclonus, are rhythmical kicking of the
lower extremities. They increase with age and are most commonly identified in association with other sleep disorders.
While an overwhelming majority (>80%) of RLS patients
have periodic limb movements, only a fraction of those
individuals who have limb movements during sleep have
RLS. PLMS have also been included in the obstructive sleep
apnea hypopnea syndrome (see Figure 1), the upper airway
resistance syndrome, narcolepsy, and REM sleep behavior
disorder. PLMS are also frequently seen in patients who are
taking antidepressants and probably represent a serotonergic
phenomenon. When patients with complaints of insomnia
or hypersomnia have PLMS and no other sleep disorder or
relevant (e.g., antidepressant) medication use is present,
they may be diagnosed with periodic limb movement disorder (PLMD). Such patients are probably rare. Patients with
PLMS associated with RLS symptoms should be treated for
RLS, but there is no evidence to support pharmacologic
treatment of PLMS/PLMD, and there is no agent FDAapproved for this indication. The revised diagnostic criteria
for PLMD take into account the coexistence of leg jerks with
many medical conditions and medications, and also ‘raise
the bar’ for the ‘abnormal’ number of periodic limb movements from 5 to 15 for adults (Table 2).
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Dopamine receptor agonists are the first-line treatment and
are the only agents that are Food and Drug Administration
(FDA)-approved for RLS. The two dopamine receptor agonists
available for this purpose in the United States are ropinirole
and pramipexole; both are FDA-approved. Pramipexole is renally excreted, and the dose is 0.125–0.75 mg day 1 in single or
divided doses, averaging 0.25 mg day 1. Ropinirole is hepatically excreted, and the effective dose is in the range of 1.5–6 mg
day 1 in single or divided doses, averaging about 2 mg day 1.
The main side effects of these agents are nausea, vomiting,
orthostasis, dizziness, sleepiness, insomnia, and compulsive
behavior. Because of delays in absorption, these agents
work best if given at least an hour before symptom onset
typically occurs.
Use of other agents is off-label and not clearly supported by
the literature. As mentioned, RLS is a particular issue in pregnancy. None of the medications commonly used to treat RLS is
safe in pregnancy. For pregnant women, folic acid has been
reported to improve symptoms in those who are folate deficient. Iron replacement may also reduce or eliminate symptoms in patients who have serum ferritin levels below 45 mg l 1.
Recently, pneumatic compression devices have been shown to
relieve symptoms in a randomized, double-blinded, shamcontrolled trial.
One consideration in the pharmacologic treatment of RLS
is the rather large placebo effect, which has been reported to be
about 40%. Another consideration in the pharmacologic management of RLS is the appearance of augmentation. The International Restless Legs Study Group has established diagnostic
standards for the dopaminergic augmentation of RLS, based on
usual time of RLS symptom onset each day, number of body
parts with RLS symptoms, latency to symptoms at rest, severity
of the symptoms, time of occurrence, and effects of dopaminergic medication on symptoms. In brief, augmentation
may be said to have occurred if the symptoms have spread to
other body parts (e.g., from calves to thighs), occur earlier in
the evening than originally, or increase in severity. Augmentation occurs frequently with the (off-label) regular use of
carbidopa; it also occurs, but much less frequently, with ropinirole and pramipexole. Evidence-based recommendations for
management of augmentation are lacking, but some suggested
strategies are to take the dose earlier in the day and split the
existing dose into early evening and bedtime doses. Augmentation and progression of the disease are difficult, if not impossible, to distinguish. This, coupled with the large placebo
effect associated with any treatment for this condition, results
in the lack of a clear-cut approach to the management of
augmentation.
Periodic Limb Movements
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weight, caffeine intake, and smoking have been associated
with increased likelihood of endorsing RLS symptoms. RLS
is also associated with earning a lower income, sedentary
lifestyle, and reduced alcohol consumption. Nonpharmacologic measures therefore should include education, moderate
exercise, smoking cessation, caffeine reduction or elimination, and discontinuation of exacerbating medications if it is
safe to do so. Some have found that working at night and
sleeping in the day has helped. Iron supplementation should
be given to those who are iron deficient.
111
Gender Differences in Periodic Limb Movements
Women may be more likely to have periodic limb movements
than are men because they are more likely to be diagnosed with
depression and to be taking antidepressants. In addition, they
are more likely to have subtle or occult sleep-disordered
breathing (e.g., upper airways resistance syndrome) than are
men, and the resulting arousal-associated leg jerks may be
misdiagnosed as PLMD.
Bruxism
Sleep-related bruxism is characterized by repetitive clenching
or grinding of the teeth during sleep. The primary consequences of this are tooth wear and jaw pain. Bruxism probably has a prevalence of about 15% and is highest in
childhood. Bruxism tends to occur in families. Anecdotally,
bruxism is thought to be associated with anxiety, stress,
tooth malocclusion, or a side effect of medications such as
antidepressants. It has also been reported with sleep apnea,
Huntingdon’s disease, and Parkinson’s disease. Use of
splints or tooth guards, made by a dentist, is the most
common form of treatment, but behavioral therapy, biofeedback, botulinum toxin, and correction of misaligned
teeth may also be effective.
There are no reported gender differences in the prevalence,
manifestations, or treatment of bruxism.
112
Special Conditions, Disorders, and Clinical Issues of SRMD | Gender Differences in Sleep-Related Movement Disorders
~LEOG
0
~REOG
0
~C3A2
0
~C4A1
0
~O1A2
0
~O2A1
0
0
~Chin
128
0
Pressure
SAO2
90
Micro
128
Chest
128
ABD
128
00
Body
~Left Leg
98
96
S S
S
S2
S2
95
S
95
S
S
98
S
96
S
S
93
S
93
S
S
98
S
94
S
93
S
S
97
93
S
S
0
~Right Leg 0
Stage
2
202 203
S2
S2
S2
S2
203 204
S2
S2
S2
204 205
60"
S2
S2
S2
205 206
S
S
S2
S2
206 207
120"
S
S
99
S
96
S
95
S
S
98
94
S
S
S
S
S2
S2
S2
S2
207 208
S2
S2
208 209
180"
S2
98
95
95
S
S
S2
S
S2
99
98
S
S
S2
209 210
98
98
96
S
S S
S
S
S2
S2
S2
S2
210 211
21
240"
VI
5 min.
97
95
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Flow
Table 2
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Figure 1 In this 5-min, compressed PSG tracing, periodic limb movements are seen in the leg lead channels (‘left leg, right leg’). However,
inspection reveals that these leg movements are part of the arousal response to obstructive respiratory events, seen clearly in the respiratory
channel (‘flow, pressure’). This common finding likely accounts for many cases of ‘periodic limb movement disorder (PLMD)’ and is a major reason
why the diagnosis of PLMD should be made only after careful exclusion of sleep-disordered breathing, medication side effects, or other causes
of movement.
Diagnostic Criteria for Periodic Limb Movement Disorder
EL
A. Polysomnography demonstrates repetitive, highly stereotyped, limb
movements that are:
1. 0.5–5 s
2. Of amplitude >25% of toe dorsiflexion during calibration
3. In a sequence of four or more movements
4. Separated by an interval of more than 5 s (from limb-movement
onset) and less than 90 s (typically an interval of 20–40 s)
B. The PLMS index exceeds 5 per hour in children and 15 per hour in
most adult cases
C. There is clinical sleep disturbance or a complaint of daytime fatigue
D. The PLMS are not better explained by another current sleep disorder,
medical or neurological disorder, mental disorder, medication use, or
a substance use disorder
Note: If PLMS are present without clinical sleep disturbance, the PLMS can be noted as
a polysomnographic finding, but criteria are not met for a diagnosis of PLMD.
From American Academy of Sleep Medicine (2005) International Classification of Sleep
Disorders: Diagnostic and Coding Manual, 2nd edn., p. 185. Westchester, IL: American
Academy of Sleep Medicine.
Other Sleep-Related Movement Disorders
Other sleep-related movement disorders include leg cramps
and movement disorders due to drugs or medical conditions.
Data about gender differences in these conditions are lacking.
See also: Psychiatric Associations of Sleep Loss/Deprivation:
Antidepressant Effects of Sleep Manipulation; Special Conditions,
Disorders, and Clinical Issues for Insomnia: Gender
Differences; Special Conditions, Disorders, and Clinical Issues
of SRBD: Gender-Specific Differences in Patients with Obstructive
Sleep Apnea–Hypopnea Syndrome; Special Populations Affected
by Sleep Loss/Deprivation: Pregnancy and Postpartum.
Further Reading
Allen RP, Walters AS, Montplaisir J, et al. (2005) Restless legs syndrome prevalence
and impact: REST general population study. Archives of Internal Medicine 165:
1286–1292.
American Academy of Sleep Medicine (2005) International Classification of Sleep
Disorders: Diagnostic and Coding Manual, 2nd edn., p. 185. Westchester, IL:
American Academy of Sleep Medicine.
Araujo SM, de Bruin VM, Nepomuceno LA, et al. (2010) Restless legs syndrome in
end-stage renal disease: Clinical characteristics and associated comorbidities.
Sleep Medicine 11: 785–790.
Aukerman MM, Aukerman D, Bayard M, Tudiver F, Thorp L, and Bailey B (2006)
Exercise and restless legs syndrome: A randomized controlled trial. Journal of
the American Board of Family Medicine 19: 487–493.
Baughman KR, Bourguet CC, and Ober SK (2009) Gender differences in the association
between antidepressant use and restless legs syndrome. Movement Disorders
24: 1054–1059.
Beneš H, von Eye A, and Kohnen R (2009) Empirical evaluation of the
accuracy of diagnostic criteria for restless legs syndrome. Sleep Medicine
10: 524–530.
Special Conditions, Disorders, and Clinical Issues of SRMD | Gender Differences in Sleep-Related Movement Disorders
ER
Manconi M, Govoni V, De Vito A, et al. (2004) Restless legs syndrome and pregnancy.
Neurology 63: 1065–1069.
Montplaisir J, Michaud M, Denesle R, and Gosselin A (2000) Periodic leg movements
are not more prevalent in insomnia or hypersomnia but are specifically
associated with sleep disorders involving a dopaminergic impairment. Sleep
Medicine 1: 163–167.
Pantaleo NP, Hening WA, Allen RP, and Early CJ (2010) Pregnancy accounts for
most of the gender difference in prevalence of familial RLS. Sleep Medicine
11: 310–313.
Phillips B, Hening W, Britz P, and Mannino DM (2006) Prevalence and correlates of
restless legs syndrome: Results from the 2005 national sleep foundation poll. Chest
129: 76–80.
Phillips B, Young T, Finn L, et al. (2000) Epidemiology of restless legs symptoms in
adults. Archives of Internal Medicine 160: 2137–2141.
Pichietti D, Allen RP, Walters AS, et al. (2007) Restless legs syndrome: Prevalence
and impact on children and adolescents – The Peds REST study. Pediatrics
120: 253–266.
Rottach KG, Schaner BM, Kirch MH, et al. (2008) Restless legs syndrome as side
effect of second generation antidepressants. Journal of Psychiatric Research
43: 70–75.
Stefansson H, Rye DB, Hicks A, Petursson H, et al. (2007) A genetic risk factor for
periodic limb movements in sleep. The New England Journal of Medicine
357: 639–647.
Stehlik R, Arvidsson L, and Ulfberg J (2009) Restless legs syndrome is common among
female patients with fibromyalgia. European Neurology 61: 107–111.
Sun ER, Chen CA, Ho G, Earley CJ, and Allen RP (1998) Iron and the restless legs
syndrome. Sleep 21: 371–377.
Tan EK, Seah A, See SJ, Lim E, Wong MC, and Koh KK (2001) Restless legs
syndrome in an Asian population: A study in Singapore. Movement Disorders
16: 577–579.
The National Heart, Lung, and Blood Institute (2008) Restless legs syndrome:
Detection and management in primary care. NHLBI-NIH, March 2000. The REMS
study. Sleep 31: 944–952.
Winkelman JW, Chertow GM, and Lazarus JM (1996) Restless legs syndrome
in end-stage renal disease. American Journal of Kidney Diseases
28: 372–378.
Yang C, White DP, and Winkelman JW (2005) Antidepressants and periodic leg
movements of sleep. Biological Psychiatry 58: 510–514.
Yilmaz K, Kilincaslan A, Aydin N, and Kor D (2010) Prevalence and correlates of
restless legs syndrome in adolescents. Developmental Medicine and Child
Neurology 53(1): 40–47. http://dx.doi.org/10.1111/j.1469-8749.2010.03796.x.
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Berger K, Luedemann J, Trenkwalder C, John U, and Kessler C (2004) Sex and the
risk of restless legs syndrome in the general population. Archives of Internal
Medicine 164: 196–202.
Bjorvatn B, Leissner L, Ulfberg J, et al. (2005) Prevalence, severity and risk factors of
restless legs syndrome in the general adult population in two Scandinavian
countries. Sleep Medicine 6: 307–312.
Botez MI and Lambert B (1977) Folate deficiency and restless-legs syndrome in
pregnancy. The New England Journal of Medicine 297: 670.
Chervin R (2001) Periodic leg movements and sleepiness in patients evaluated for
sleep-disordered breathing. American Journal of Respiratory and Critical Care
Medicine 164: 1454–1458.
Connor JR, Boyer PJ, Menzies SL, et al. (2003) Neuropathological examination
suggests impaired brain iron acquisition in restless legs syndrome. Neurology
61(22): 304–309.
Dao TT and Lavigne GJ (1998) Oral splints: The crutches for temporomandibular
disorders and bruxism? Critical Reviews in Oral Biology and Medicine 8: 345.
Exar EN and Collop NA (2001) The association of upper airway resistance with periodic
limb movements. Sleep 24: 188–192.
Frauscher B, Gschliesser V, Brandauer E, et al. (2009) The severity range of restless
legs syndrome (RLS) and augmentation in a prospective patient cohort: Association
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Relevant Websites
http://www.cdc.gov/sleep/ – The Center for Disease Control’s Public Education site for
sleep and its disorders.
http://www.nhlbi.nih.gov/about/ncsdr/patpub/patpub-a.htm – The National Institute of
Health’s Public Education site for sleep and its disorders.
http://www.rls.org – The Restless Legs Syndrome Foundation Website.