A common parasomnia, non−rapid eye movement (NREM) sleep arousal disorder, is described as being characterized by either somnambulism (ie, sleepwalking) or sleep terrors. The following describes NREM sleep arousal disorder, sleepwalking type.
The history should address the following:
Reported symptoms may include the following:
Sleepwalking should be differentiated from the following conditions:
Physical and neurologic examinations are typically normal in sleepwalking children.
See Presentation for more detail.
Diagnosis of sleepwalking should take into account miscellaneous sleep disorders, NREM parasomnias, and rapid eye movement (REM)–related parasomnias. Relevant miscellaneous sleep disorders include the following:
Normal NREM parasomnias are characterized by the following:
REM-related parasomnias are much less common in children than in adults.
Other problems to be considered include the following:
Principles of workup include the following:
See DDx andWorkup for more detail.
General management principles include the following:
See Treatment for more detail.
Parasomnias are sleep-wake disorders characterized by undesirable motor, verbal, or experiential phenomena occurring in association with sleep, specific stages of sleep, or sleep-awake transition phases. In the American Psychiatric Association (APA) Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), one common parasomnia, non-REM (NREM) sleep arousal disorder, is described as being characterized by either somnambulism (ie, sleepwalking) or sleep terrors.[1]
For patient education resources, see the Sleep Disorders Center, as well as Disorders That Disrupt Sleep (Parasomnias), Sleepwalking, and REM Sleep Behavior Disorder.
The specific DSM-5 criteria for NREM sleep arousal disorder, sleepwalking type, are as follows[1] :
In addition, if warranted, the sleepwalking type can be further differentiated into 1 of 2 subtypes:
It was once theorized that sexsomnia occurred in individuals acting out their dreams as a consequence of an underlying psychological condition; however, such theories have been debunked. Sexual behaviors of all types may occur during a sleep automatism, ranging from explicit sexual vocalizations to violent masturbation to complex sexual acts that may include fondling, cunnilingus, fellatio, and even vaginal and anal sex.[2]
Features of sexsomnia are analogous to those of other NREM parasomnias that occur during what is known as a confusional arousal during the deeper stages of sleep. Throughout this time, the brain is in a hybridized state in which cortical areas (which control higher thought processing and reasoning) are deactivated while more primitive functions (eg, eating and sex) remain active. Individuals are typically amnestic for the episode. Those who commit these sexual acts typically have a family or personal history of other parasomnias.
In a small number of sexsomnia cases, medicolegal issues have arisen, though the actual forensic implications remain nebulous. Several of the cases have points in common—namely, the involvement of a male perpetrator younger than 35 years, accusations of sexual assault or rape, claims of amnesia after the event, and a history of prolonged complex somnambulism. This unusual parasomnia is more common than was previously thought; many patients with the behavior were identified only after specific questions were asked.[3, 4]
In addition to SRE, the literature describes another disorder involving the consumption of food during the night or at bedtime: night-eating syndrome (NES). A clear distinction should be drawn between SRE and NES: the latter is not categorized as a parasomnia, because full consciousness is maintained during NES episodes.
Although NES was first described by Stunkard et al in 1955, no uniform definition of this disorder has yet been adopted. NES is characterized by consumption of excessive amounts of food either before bed or during nocturnal awakenings. It is up to 4 times more common in females and tends to have an onset in late adolescence.[5, 6] According to the most commonly used current definition, NES is present if patients report the following:
Whether NES should be differentiated from nocturnal eating syndrome is not clear in the literature. However, the terms may be usefully distinguished as follows[7] :
SRE, on the other hand, can be conceptualized as a binge eating disorder that incorporates the disordered arousal, confusional behavior, and amnesia of an NREM parasomnia.[8] Episodes often occur within the first 2-3 hours of sleep, with ingestion of foods (commonly high in carbohydrates) in a hurried, uncontrollable manner. In contrast to other NREM parasomnias, a fluctuation in level of awareness exists between episodes within the same night. There is relatively high comorbidity with restless legs syndrome (RLS).[9]
The parasomnias have been thought to represent not pathologic cerebral functioning but, rather, a response to central nervous system (CNS) activation that results in sleep-wake or rapid eye movement (REM)–NREM state confusion, instability, or overlap. However, studies have demonstrated differences between sleep patterns and neuronal sleep control mechanisms in individuals who have parasomnias and corresponding patterns and mechanisms in individuals who do not.
Normal sleep involves cyclic hypnic patterns throughout the night between wakefulness, NREM, and REM states. The CNS remains active during all sleep-wake states, though rapid changes are required in neural networks, rhythms, and neurotransmitters with state changes. The length of each cycle averages 50 minutes for a full-term newborn, increasing to approximately 90 minutes by adolescence.
Slow-wave sleep (SWS) normally occurs in the first 2 hypnic cycles; younger children have an additional SWS period toward the end of the sleep period. Children typically enter their deepest sleep within 15 minutes of sleep onset, and this first SWS period lasts from 45-75 minutes. This explains why it is easy to move children without rousing them soon after sleep onset.
Parasomnias occur as children are caught in a mixed state of transition from one sleep cycle to the next (eg, from NREM sleep to wakefulness). This transition state is characterized by a high arousal threshold, mental confusion, and unclear perception.
Sleepwalkers appear to have an abnormality in SWS regulation. The dissociation that occurs between body and mind sleep appears to arise from activation of thalamocingulate pathways with persisting deactivation of other thalamocortical arousal systems. The first SWS period of the night is considered to be more disturbed in somnambulistic individuals, and the entire NREM-REM sleep cycle is more fragmented. Because these disorders occur more frequently in children, these differences have been suggested as signs of CNS immaturity.
Sleepwalking occurs more frequently in monozygotic twins and is 10 times more likely if a first-degree relative has a history of sleepwalking. An increased frequency of DQB1*04 and *05 alleles is reported. DQB1 genes have also been implicated in narcolepsy and other disorders of motor control during sleep (eg, REM behavior disorder).
Sleep deprivation, chaotic sleep schedules, fever, stress, magnesium deficiency, and chemical or drug intoxication (eg, alcohol) can trigger parasomnias. Various medications can also serve as triggers, including the following:
The length and depth of SWS, which is greater in young children, may be a factor in the increased frequency of parasomnias in children. Conditions such as pregnancy and menstruation are known to increase frequency in patients with parasomnias.
Medical conditions associated with parasomnias include the following:
Chronic sleepwalking, especially in adults, is frequently associated with sleep-disordered breathing. Treatment of the sleep-disordered breathing with continuous positive airway pressure (CPAP) or surgery typically improves or resolves the sleepwalking. Noncompliance with CPAP is associated with persistence or recurrence of sleepwalking. Serotonin has been postulated as the physiologic link between these 2 disorders.
Thyrotoxicosis has been associated with an increased incidence of sleepwalking,[16] and achievement of euthyroidism is associated with improvement or resolution of the symptoms. Sleepwalking may occur as an early symptom, and the onset of sleepwalking in a patient out of the normal expected age range warrants evaluation for hyperthyroidism. The mechanism for the sleepwalking is considered to be increased fatigue in combination with longer periods of NREM sleep.
Psychiatric disorders associated with parasomnias include the following:
Disorders of arousal are all more prevalent in children than in adults. Confusional arousals are reported in 5-15% of children. Sleep terrors have an incidence of approximately 1%. The lifetime prevalence of nocturnal wandering with abnormal state of consciousness among US adults may be as high as 29.2%.[17] ; however, the prevalence of sleepwalking disorder, marked by repeated episodes and impairment or distress, is much lower (1-5%).[1]
In Sweden, the incidence of quiet sleepwalking is reported as 40%, with a yearly prevalence of 6-17%. Only 2-3% report more than 1 episode per month, and 33% report only a single episode. In a survey of adults in the United Kingdom, 2.2% reported having night terrors, 2.0% reported sleep walking, and 4.2% reported confusional arousals.
Sleepwalking occurs most commonly in middle childhood and preadolescence, with a peak incidence in children aged 11-12 years. A Canadian study of sleep data from a cohort of 1,940 children born in 1997 and 1998 in Quebec found prevalence of sleepwalking peaked at age 10 years. Data also show that prevalence of childhood sleepwalking increases with the degree of parental history of sleepwalking: 22.5% (95% CI, 19.2%-25.8%) for children without a parental history of sleepwalking, 47.4% (95% CI, 38.9%-55.9%) for children who had 1 parent with a history of sleepwalking, and 61.5% (95% CI, 42.8%-80.2%) for children whose mother and father had a history of sleepwalking.[18]
Confusional arousals are most common in toddlers and preschool-aged children. Violent or sexual activity is more likely in adults. Sleepwalking and confusional arousals have an equal incidence in males and females. Females are more likely to sleep eat. Sleepwalking occurs more often in females during childhood but more often in males in adulthood. No racial predilection is known.
The NREM parasomnias are rarely associated with any significant morbidity or long-term sequelae. Although disruptive and frightening for parents in the short term, these disorders rarely cause injury (though children can strike objects during sleepwalking and occasionally become injured). The prognosis for resolution with maturation is excellent.
Sleep-disordered breathing and, to a lesser extent, RLS have been associated with sleepwalking in children, though less often than in adults. The incidence of associated sleep disorders has been reported to be as high as 61%. Prolonged disturbed sleep may be associated with school and behavioral issues. A relationship with hyperactivity is suggested but not clear.
In adolescents and adults, morbidity may be more significant. More complex motor behaviors (eg, driving a car, cooking, eating, or playing a musical instrument) have been reported. Behaviors injurious to the patient or bed partner may be associated with forensic medicine implications.
An increased incidence of psychiatric disorders such as neuroses, panic disorder, phobias, and suicidal ideations has been reported in both these groups. Sleep-disordered breathing, including a sense of choking or blocked breathing, has also been reported. The respiratory events may have a deleterious effect on sleep by increasing arousals and sleep fragmentation.
Adolescents with sleep terrors or sleepwalking have an increased prevalence of other sleep disorders, neurotic traits, and other psychiatric disorders.
Serious injury, sexual misconduct, and violent behavior occurring during somnambulism have been reported in adults, albeit rarely. Most serious injuries have occurred as a result of leaping through windows. Some apparent “suicides” have likely been the unfortunate result of a sleep behavior. The violent behavior aspect, though rare overall, appears to occur more frequently in men than in women. Such behavior toward others has occasionally been used as a legal defense.
The most common pediatric parasomnia disorders of arousal include sleepwalking, confusional arousals, and sleep terrors.[19] Parasomnia events have a predilection for occurring during deep sleep (stages III and IV, or slow-wave sleep [SWS]), are known to occur during all stages of non−rapid eye movement (NREM) sleep, and are possible at any time during the night. Because most SWS is achieved in the earlier segments of the sleep period, these phenomena are usually seen in the first one third of the sleep cycle and are rarely seen during naps.
A general medical history and sleep-related medical history are usually sufficient to permit differentiation of parasomnias from other disorders. Pertinent issues include the following:
Nocturnal frontal-lobe seizures and some psychiatric conditions present the most difficult diagnostic dilemmas. A history of stereotypical short attacks that repeat during the night, most frequently during stage II sleep, suggests seizures rather than a parasomnia. Onset in later childhood or adolescence, persistence into adulthood, recurring nocturnal agitation, and daytime complaints such as fatigue or sleepiness are also suggestive of a seizure disorder.
Sleepwalking episodes may range from quiet walking about the room to agitated running or attempts to “escape.” Subjects may later report attempting to escape dangerous situations or terrifying threats. Typically, the eyes are open and have a glassy, staring appearance as the child quietly roams the house.
On questioning, the child’s responses are slow or absent. If returned to bed without awakening, the child usually does not remember the event. Older children, who may awaken more easily at the end of an episode, often are embarrassed by the behavior (especially if it was inappropriate).
Sleepwalking has no association with previous sleep problems, sleeping alone in a room or with others, achluophobia (fear of the dark; also referred to as nyctophobia, scotophobia, or lygophobia), or anger outbursts. Some studies suggest that children who sleepwalk may have been more restless sleepers when aged 4-5 years and may have been more restless with more frequent awakenings during the first year of life.
Episodes of confusional arousal consist of disorientation, memory impairment, and slow mentation and often are accompanied by inconsolable crying and thrashing movements in bed. This disorder is common in younger children but decreases in frequency with age. In infants, episodes manifest by crying and moving about in bed. The eyes may be closed or opened, as in sleep terrors, but the child does not appear to feel panic.
Events typically last from 3-13 minutes and range in frequency from 2 times per night to 2 times per year. Attempting to awaken the child often prolongs the course, and successful wakening by parents typically brings about an end to the episode.
Sleep terrors are the most anxiety-provoking parasomnias for parents. Episodes frequently begin with a “blood-curdling” scream, which is accompanied by the appearance of panic with wide-open eyes, tachycardia, tachypnea, dilated pupils, diaphoresis, and flushing. This may be followed by panic-driven motor activity, such as hitting the wall or running around the room. Although the behavior typically is not dangerous, it is sometimes violent enough to result in injury to the patient or others; property damage also may result.
The inability of the parent to console the child is a hallmark of the episode (which is typically shorter than confusional arousals), and amnesia for the event is usually complete. Sleep terrors usually resolve by adolescence, though the disorder occasionally persists into adulthood.
Physical and neurologic examinations are typically normal in these children.
No specific laboratory studies are indicated in the workup of routine parasomnias. No imaging studies are required.
Polysomnography (PSG), with or without multiple sleep latency testing, should be reserved for the few cases in which the diagnosis is still unclear after a careful history and physical examination. The abnormal behavior during slow-wave sleep (SWS) is generally diagnostic. Sleep deprivation can be used as a tool to induce somnambulistic episodes in the sleep laboratory.
Microarousals and sleep state disorganization are observed frequently and often noted on electroencephalography (EEG) alone, if the study is performed during nocturnal sleep. Hypersynchronous slow delta-wave activity has been observed in the sleep EEG of sleepwalkers; however, controversy remains regarding these findings on PSG.
General management principles include the following:
For long-term management, relaxation techniques, mental imagery, and anticipatory awakenings are preferred. The first 2 techniques should be undertaken only with the help of an experienced behavioral therapist or hypnotist. Anticipatory awakenings consist of waking the child approximately 15-20 minutes before the usual time of an event and then keeping him or her awake through the time during which the episodes usually occur. Ongoing reassurance should be provided at regular health maintenance visits.