Sleepwalking, also known as somnambulism or noctambulism, is a phenomenon of combined sleep and wakefulness. It is classified as a sleep disorder belonging to the parasomnia family. It can also be understood as a disorder of state dissociation, which features of wakefulness and deep non-REM sleep occurring simultaneously in different brain regions. It occurs during the slow wave stage of sleep, in a state of low consciousness, with performance of activities that are usually performed during a state of full consciousness. These activities can be as benign as talking, sitting up in bed, walking to a bathroom, consuming food, and cleaning, or as hazardous as cooking, driving a motor vehicle, violent gestures and grabbing at hallucinated objects. Although sleepwalking cases generally consist of simple, repeated behaviors, there are occasionally reports of people performing complex behaviors while asleep, although their legitimacy is often disputed. Sleepwalkers often have little or no memory of the incident, although some partial recall has been reported. Although their eyes are open, their expression is dim and glazed over. This may last from 30 seconds to 30 minutes. Sleepwalking occurs during slow-wave sleep (N3) of non-rapid eye movement sleep (NREM sleep) cycles. It typically occurs within the first third of the night when slow-wave sleep is most prominent. Usually, it will occur once in a night, if at all.
Signs and symptoms Sleepwalking is characterized by:
partial arousal during non-rapid eye movement (NREM) sleep, typically during the first third of the night dreamy content that may or may not be recalled when awake dream-congruent motor behavior that may be simple or complex impaired perception of the environment impaired judgement, planning and problem-solving. Despite how it is portrayed in many cultures (eyes closed and walking with arms outstretched), the sleepwalker's eyes are open but may appear as a glassy-eyed stare or blank expression and pupils are dilated. Despite their reduced sensory perception due to being asleep, sleepwalkers demonstrate some ability to navigate their surrounding environment due to a combination of simple stumbling and habit. They are often disoriented, consequent to awakening: the sleepwalker may be confused and perplexed, and might not know why or how they got out of bed; however, the disorientation will fade within minutes. They may talk while sleepwalking, but the talk typically does not make sense to the observer. There are varying degrees of amnesia associated with sleepwalking, ranging from no memory at all, vague memories or a narrative.
Associated disorders Most studies look at sleep disorders in adults, but children can also be affected. In the ten percent of the population that experiences sleep-related disorders, children are most affected due to their developing brains. A study conducted in Australia, looked at sleepwalking and its association with sleep behaviors in children. It was found that sleepwalking could be associated with children's bedtime routines. Those who have behavioral problems are more likely to develop a sleep disorder and should be assessed. The relationship between sleepwalking and the behavioral and emotional problems are more associated than their bedtime routines. This may very well be because sleep related disorders and sleepwalking happen simultaneously; one cannot exist without the other. In the study "Sleepwalking and Sleep Terrors in Prepubertal Children" it was found that, if a child had another sleep disorder – such as restless leg syndrome (RLS) or sleep-disorder breathing (SDB) – there was a greater chance of sleepwalking. The study found that children with chronic parasomnias may often also present SDB or, to a lesser extent, RLS. Furthermore, the disappearance of the parasomnias after the treatment of the SDB or RLS periodic limb movement syndrome suggests that the latter may trigger the former. The high frequency of SDB in family members of children with parasomnia provided additional evidence that SDB may manifest as parasomnias in children. Children with parasomnias are not systematically monitored during sleep, although past studies have suggested that patients with sleep terrors or sleepwalking have an elevated level of brief EEG arousals. When children receive polysomnographies, discrete patterns (e.g., nasal flow limitation, abnormal respiratory effort, bursts of high or slow EEG frequencies) should be sought; apneas are rarely found in children. Children's respiration during sleep should be monitored with nasal cannula or pressure transducer system or esophageal manometry, which are more sensitive than the thermistors or thermocouples currently used in many laboratories. The clear, prompt improvement of severe parasomnia in children who are treated for SDB, as defined here, provides important evidence that subtle SDB can have substantial health-related significance. Also noteworthy is the report of familial presence of parasomnia. Studies of twin cohorts and families with sleep terror and sleepwalking suggest genetic involvement of parasomnias. RLS and SDB have been shown to have familial recurrence. RLS has been shown to have genetic involvement. Sleepwalking may also accompany the related phenomenon of night terrors, especially in children. In the midst of a night terror, the affected person may wander in a distressed state while still asleep, and examples of sufferers attempting to run or aggressively defend themselves during these incidents have been reported in medical literature. In some cases, sleepwalking in adults may be a symptom of a psychological disorder. One study suggests higher levels of dissociation in adult sleepwalkers, since test subjects scored unusually high on the hysteria portion of the "Crown-Crisp Experiential Index". Another suggested that "A higher incidence [of sleepwalking events] has been reported in patients with schizophrenia, hysteria and anxiety neuroses". Also, patients with migraine headaches or Tourette syndrome are 4–6 times more likely to sleepwalk.
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