eMedicine Specialties > Neurology > Sleep-Related Diseases

Somnambulism (Sleep Walking)

Gregory Ackroyd, MD, Consulting Staff, North Bay Sleep Medicine Institute
O'Neill F D'Cruz, MD, Professor, Departments of Neurology and Pediatrics, Director, Pediatric Sleep Program, University of North Carolina; Stephen J Sharp, MD, Chief, Department of Pediatric Neurology, Keesler Medical Center
Contributor Information and Disclosures

Updated: Mar 8, 2007

Introduction

Background

Somnambulism (ie, sleepwalking) is a disorder of arousal that falls under the parasomnia group. Parasomnias are undesirable motor, verbal, or experiential events that occur during sleep. These phenomena occur as primary sleep events or secondary to systemic disease. They are categorized as those occurring in rapid eye movement (REM) sleep; those occurring during non–rapid eye movement (NREM) sleep; and miscellaneous types that do not relate to any specific sleep state.

Pathophysiology

The parasomnias have been thought to represent not pathologic cerebral functioning but rather a response to CNS activation that results in sleep-wake or REM-NREM state confusion, instability, or overlap. Recent studies, however, demonstrate differences between sleep patterns and neuronal sleep control mechanisms in individuals with parasomnias compared with those without. Normal sleep involves cyclic hypnic patterns throughout the night between wakefulness, NREM, and REM states. The CNS remains active during all sleep-wake states, although 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, NREM-wakefulness). This transition state is characterized by a high arousal threshold, mental confusion, and unclear perception.

Sleepwalkers appear to have an abnormality in slow wave sleep 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 slow wave sleep 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.

Frequency

United States

Disorders of arousal are all more prevalent in children than adults. Confusional arousals are reported in 5-15% of children. Sleep terrors have an incidence of approximately 1%.

International

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.

Mortality/Morbidity

The NREM parasomnias are rarely associated with any significant morbidity, although children can strike objects during sleepwalking and occasionally become injured. Sleep-disordered breathing and, to a lesser extent, restless legs syndrome have been associated in children, although with less frequency than reported in adults. The incidence of associated sleep disorders has been reported to be as high as 61%.

Morbidity in adolescents and adults may be more significant. More complex motor behaviors such as driving a car, cooking, eating, or playing a musical instrument have been reported. Injurious behaviors to the patient and/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.

Race

No racial predilection is known.

Sex

Sleepwalking and confusional arousals have an equal incidence in males and females. Sleep terrors are more common in boys.

Age

Sleepwalking occurs most commonly in middle childhood and preadolescence, with a peak incidence in children aged 11-12 years. Confusional arousals are most common in toddlers and preschool-aged children. Sleep terrors occur most commonly in children aged 4-12 years.

Clinical

History

The most common pediatric parasomnia disorders of arousal include sleepwalking, confusional arousals, and sleep terrors. Parasomnia events have a predilection for occurring during deep sleep (stages III and IV, or SWS), are known to occur during all stages of NREM sleep, and are possible at any time during the night. As most SWS is achieved in the earlier segments of the sleep period, these phenomena usually are seen in the first one third of the sleep cycle and rarely during naps.

• General and sleep related medical history is usually sufficient to differentiate parasomnias from other disorders. Pertinent questions include the following:
  • Detailed description of the event
  • Level of consciousness before, during, and after the event
  • Time of night and sleep cycle when the events occur
  • Daytime sleepiness
  • Associated injury
  • Memory of the event
  • Family history
  • Any precipitating factors
• 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 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 with a glassy, staring appearance as the child quietly roams the house.
  • On questioning, 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), or anger outbursts.
  • Some studies suggest that children who sleepwalk may have been more restless sleepers when aged 4-5 years and more restless with more frequent awakenings during the first year of life.
• Confusional arousals
  • Episodes 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
  • These are the most anxiety provoking 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.
  • While typically not dangerous, the behavior 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, although the disorder occasionally persists into adulthood.

Physical

Physical and neurological examinations are typically normal in these children.

Causes

• Genetic
  • 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 such as REM behavior disorder.
• Environmental: Sleep deprivation, chaotic sleep schedules, fever, stress, magnesium deficiency, and chemical or drug intoxication (eg, alcohol), sedative/hypnotics (eg, Zolpidem), antidepressants (eg, bupropion, paroxetine, amitriptyline), neuroleptics (eg, lithium, reboxetine), minor tranquilizers, stimulants, antibiotics (eg, fluoroquinolone), anti-Parkinson medications (eg, levodopa), anticonvulsants (eg, topiramate), and antihistamines can trigger parasomnias.
• Physiologic
  • 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.
• Associated medical conditions
  • Arrhythmias
  • Chronic paroxysmal hemicrania
  • Migraine
  • Fever
  • Gastroesophageal reflux
  • Nocturnal asthma
  • Nocturnal seizures
  • Obstructive sleep apnea: Children with obstructive sleep apnea or Tourette syndrome are at greater risk of having parasomnias along with their underlying disorder.
  • 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 two disorders.
  • Psychiatric disorders
    • Posttraumatic stress disorder
    • Panic attack
    • Dissociative states
  • Hyperthyroidism: Thyrotoxicosis has been associated with an increased incidence of sleepwalking, 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 should be evaluated for hyperthyroidism. The mechanism for the sleepwalking is considered to be increased fatigue in combination with longer periods of non-REM sleep.

References

• Benign Childhood Epilepsy
• Benign Neonatal Convulsions
• Benign Positional Vertigo
• Chronic Paroxysmal Hemicrania
• Cluster Headache
• Complex Partial Seizures
• Epilepsy in Children with Mental Retardation
• Febrile Seizures
• First Seizure: Pediatric Perspective
• Headache: Pediatric Perspective
• Neonatal Seizures
• Periodic Limb Movement Disorder
• Psychogenic Nonepileptic Seizures
• REM Sleep Behavior Disorder
• Shuddering Attacks
• Temporal Lobe Epilepsy
• Tonic-Clonic Seizures
• Tourette Syndrome and Other Tic Disorders

• Sleep Disorders Center
• Disorders That Disrupt Sleep (Parasomnias) Overview
• Sleep Disorder Causes
• Sleep Disorder Symptoms
• Sleep Disorder Treatment
• Sleepwalking Overview
• REM Sleep Disorder Overview