Parasomnias are defined as undesirable events or experience that occur
predominantly during sleep. They are subclassified into disorders
of arousal from Non-REM sleep, or those associated with REM sleep.
They include disorders such as confusional arousal, sleep terrors,
sleepwalking and nightmares. The diagnosis and approach to these
disorders is further described in Chapter 509.
According to the international classification of sleep disorders, second
edition (ICSD-2), parasomnias are defined as undesirable physical
events or experiences that occur during entry into sleep, during
sleep, or during arousals from sleep. They are classified as (1) disorders
of arousals from nonrapid eye movement (NREM) sleep, (2) parasomnias
associated with rapid eye movement (REM) sleep, and (3) other parasomnias.10
Arousal from NREM Sleep11,12
Most disorders of arousals occur during slow wave sleep (SWS)
as incomplete transitions into wakefulness and are characterized
by automatic behavior, altered perception of the environment, and
a variable degree of amnesia for the event. They tend to occur in
the first third of the night when SWS is more prominent. The EEG
during the episodes demonstrates an admixture of theta, delta, and
alpha frequencies. They are thought to be due to a faulty switch
that prevents normal sleep cycle progression. They are brought out
by sleep deprivation, medications, noisy or stimulating environments, stress,
fever, and sleep fragmentation due to obstructive sleep apnea (OSA)
or periodic limb movements of sleep (PLMS). Several studies suggest
a genetic predisposition to some of the arousal parasomnias.
The clinical history in a child with any parasomnia should include
a complete description of the event, time of night when they happen, frequency
of episodes, recollection of the event by the child, and presence
during daytime naps.13 Information regarding whether the
movements are rhythmic and stereotypical and are associated with
eye deviation and focal tonic clonic activity may support an epileptic
origin to the events. A home video often proves useful for identifying
and classifying parasomnias and differentiating them from seizures.14 Examination
should focus on looking for evidence of upper airway obstruction
such as adenotonsillar hypertrophy, midfacial hypoplasia, and retrognathia.15 In
appropriate cases, a video-EEG may be indicated to rule out seizures.16 Overnight
polysomnography is indicated when there is concern for an intrinsic
sleep disorder like obstructive sleep apnea (OSA) or periodic limb
movements of sleep (PLMS), rather than to document the parasomnia,
Management usually includes reassuring parents that parasomnias are
common in childhood and that they are benign and self-remitting. Parents
should be counseled where appropriate on instituting important safety
measures including securing windows, staircases, and doors to prevent
injuries. They should be educated about avoiding sleep deprivation,
maintaining regular sleeping hours, avoiding caffeinated drinks,
and avoiding any attempts of restraining or awakening the child
during the episode which may actually be counterproductive. Scheduled
or anticipatory awakenings several minutes beforehand have been
attempted to abort such events when they happen consistently at
particular times, but in general have not been well accepted by
families. Treatment of the underlying intrinsic sleep disorder like
OSA with tonsillectomy and adenoidectomy, and oral iron supplementation
for PLMS has shown disappearance of these events. Medications should
be reserved for those rare, protracted cases with no associated
sleep disorders, with frequent parasomnias, or with a threat for injury.
Low-dose clonazepam or tricyclic antidepressants for a short duration
have been used with good success in such cases.
Sleepwalking occurs in up to 17% of children, highest
at 12 to 13 years of age, and with equal frequencies among males
and females. It is further classified as calm or agitated subtype,
with the former more common in children. The major concern during
these benign behaviors is risk for injury.
Confusional arousals occur mainly in infants and toddlers, in
up to 17.3% of the population. A typical event begins with
moaning, evolving to confused and agitated behavior lasting 5 to
15 minutes. Attempts to wake up the child fully are unsuccessful.
Sleep terrors occur in 1% to 6% of children
with peak frequency between 4 and 8 years of age. The child may
sit up suddenly and scream with a blood-curdling battle-cry. There
is an expression of intense fear on the face, accompanied by autonomic
activation including mydriasis, tachycardia, and diaphoresis. Some
children may report indistinct recollections of threat such as monsters,
spiders, and snakes from which they have to defend themselves, but
this is unusual. The event may last from a few minutes up to 20
minutes. Most cases go into a natural remission by adolescence.
Parasomnias classified as disorders of arousal from NREM sleep need
to be differentiated from nocturnal seizures. Frontal lobe seizures
are especially important because they occur predominantly in sleep,
sometimes on many occasions per night, and are characterized by
stereotypical movements, thrashing of the entire body, vocalizations,
and dystonic posturing, lasting 20 seconds to a few minutes; there
is minimal postictal drowsiness or confusion. Paroxysmal nocturnal
dystonia, which is now considered to be a frontal lobe seizure,
is characterized by an arousal from NREM sleep, accompanied by dystonic
posturing, bizarre movements of the extremities, and vocalization,
with minimal EEG correlation, because the focus of seizure onset
is deep seated in the mesial frontal region. Inpatient video-EEG
monitoring is useful in confirming the diagnosis, and differentiating
such events from nocturnal panic attacks, fugue states, conversion
reactions, and parasomnias like night terrors, confusional arousals,
Associated with REM Sleep
These are characterized by vivid dreams in the second half of
the night with intense feelings of terror or dread that typically
awaken the child from sleep. The child can be easily aroused, with
good recollection of the event. They are frequently seen between
the ages of 3 and 6 years of age. Prevalence ranges from 30% to
90% for occasional and 5% to 30% for
frequent episodes. In children, psychiatric disorders are seen more
often in those experiencing nightmares than those without nightmares. They
may also be a marker for a history of sexual abuse in children and
REM Sleep Behavior
These are characterized by enacting unpleasant and combative dreams
with complex movements that can be vigorous and violent due to lack
of REM sleep atonia. They occur more often in the sixth or seventh
decade in males and may precede onset of Parkinson’s disease,
or progressive supranuclear palsy. They are uncommon in children
but may be seen in association with use of selective serotonin reuptake
inhibitors such as fluoxetine, or accompanying narcolepsy, and Tourette
syndrome. They respond very well to small doses of clonazepam given
This is characterized by a generalized inability to speak, or
to move the trunk, head, and limbs that occur during the transitional
period between sleep and wakefulness. The episodes are brief and
transient but may be accompanied by vivid hallucinations that make them
very distressing. Usually seen with narcolepsy, they may be seen
as an isolated form in otherwise healthy individuals, with a strong
family history in some cases.
These are characterized as vivid dreams, or perceptions not based in
reality, that occur at sleep onset (hypnagogic hallucinations) or
on awakening (hypnopompic hallucinations) that occur in otherwise healthy
individuals but are frequently seen as part of the symptoms of narcolepsy.
They may be visual, tactile, auditory, or kinetic in nature. They
probably represent brief intrusion of REM sleep into NREM sleep
Nocturnal enuresis (bedwetting) (see Chapter 468)
refers to involuntary passage of urine while asleep. It occurs in almost
15% to 25% of children at 5 years of age, more
often in boys, and in almost 1% to 3% of adolescents.
It may be classified as primary (when present from
birth) or secondary (with periods of at least 6
months of dryness prior to recurrence of enuresis), nocturnal or
diurnal. Three major pathological factors have been considered as
possible etiologies: Group 1, volume dependent with polyuria; Group
2, detrussor dependent, with involuntary detrussor contractions,
and small urinary bladder; Group 3, with decreased arousability.
There are strong associations of enuresis with genetic and familial
factors, and high prevalence of secondary enuresis in children with
OSA. Treatment involves removal of inciting factors, reassurance,
behavioral programs, and use of nasal desmopressin, or oral tricyclics like
It is a harmless but potentially terrifying situation usually
occurring while a patient is falling asleep, and it is characterized
by a terrifying loud noise, accompanied by myoclonic jerks, or the
perception of a flash of light. They are very brief but lead to
intense anxiety. There is no headache or pain accompanying these
episodes, and they can begin in childhood. No treatment is needed.
Usually seen accompanying sleepwalking and daytime eating disorder,
it is characterized by out-of-control eating binges, predominantly
of carbohydrate-containing diets, 2 to 3 hours after sleep-onset,
with no recall of the event subsequently. They can be seen to begin
in childhood but are more often seen in teenage years and adulthood.
These behaviors have recently been described in association with
use of hypnotics like zolpidem.
Also called nocturnal groaning, this can occur in REM or NREM sleep
during expiration in clusters of 2 minutes to an hour, ending with
a snort, and accompanied with changes in heart rate. The onset may
begin during childhood or adolescence. The exact etiology is unknown,
and no specific therapy has been found to be effective.
Also called hypnic jerks, these are sudden whole-body jerks experienced
by individuals during sleep-wake transition. Variations include
sensory, auditory including exploding tinnitus, and visual sensations,
which may occur without the motor jerks. No treatment other than
reassurance is necessary.
Inappropriate sexual behavior occurring during sleep without
conscious awareness has been reported in adults, with onset around
adolescence in some cases.
Sleeptalking is very common in the general population and can
occur in REM or NREM sleep with a strong familial and genetic propensity.
This is characterized by diffuse headache occurring 4 to 6 hours after
sleep onset at a consistent time, lasting 30 to 60 minutes, seen
in older adults, and accompanied with nausea but no other autonomic
Also called jactatio capitis nocturna, head banging is now classified as
a rhythmic movement disorder of sleep, and is characterized by rhythmic
movements of head and body at sleep onset in infants and toddlers.
It is seen more often in children with developmental disability
or autism, but may be seen in normal children. No specific treatment
other than reassurance is indicated.