Somnambulism

Somnambulism, commonly known as sleepwalking, refers to a sleep disorder where the individual walks and does activities while in a deep sleep. Sleepwalking is most common in children between the ages of 8 and 12. During the event, the individual is disoriented to time and place and they can exhibit slow speech with blunt responses to questions or requests. There is often both anterograde and retrograde memory impairment upon waking. Anterograde memory impairment is the inability to form new memories. In contrast, retrograde impairment refers to the failure to recall old memories—some people who sleepwalk recall vague visual imagery and auditory impressions after awakening. Somnambulism occurs during non-rapid eye movement (NREM) sleep stage three when the individual is in a deep sleep and can be challenging to awaken. 

Somnambulism is classified as parasomnia, a term that encompasses disruptive sleep-related disorders that occur just before falling asleep, while sleeping, or when waking up. Other parasomnias include sleep terrors, sleep-related eating disorders, and sleep paralysis. While somnambulism is relatively benign, there can be potential for injury, such as leaving the house or falling downstairs. 

The cause of somnambulism is thought to be genetic. There is a familial predisposition to parasomnias, with studies suggesting the rate of sleepwalking is six times higher in monozygotic twins than dizygotic twins. Furthermore, it is up to three times as common in children whose parent(s) had exhibited sleepwalking when they were younger compared to children whose parent(s) did not. 

The signs of somnambulism include sitting up and walking around while appearing to be awake. It is typically seen in toddlers and school-aged children. Ambulation is typically slow, and the individual may walk around quietly. Others may seem agitated and run around the house or have confused, inappropriate behaviors. Children may injure themselves by performing dangerous behaviors such as leaving the house on a cold night and becoming hypothermic. 

Somnambulism is diagnosed from a comprehensive clinical history outlining the timing and frequency of events. This can be obtained from observing the individual who is sleepwalking since they may have little to no memory of the events. Recording and reviewing home videos can also be helpful in diagnosis. The clinician may also ask questions about personal and family history of similar events in childhood, if the individual is usually sleep deprived, and if there are symptoms of other sleep disorders, such as obstructive sleep apnea. 

Many children with somnambulism grow out of it by adulthood and do not require treatment or intervention. For those who have recurrent somnambulism and those who are at risk of injuring themselves, behavioral and preventative strategies may be used.