What is the Prevalence of Somnambulism?

Patient Presentation
A 12-year-old male came to clinic for his health supervision visit. He was well but over the past month had had 3 episodes of sleepwalking into his parents’ bedroom at night. His mother noted that his eyes were open, he would mumble and didn’t seem to know what was going on. She would take him back to his bed and he would remain there the rest of the night. The next morning he did not remember the episodes. He slept in a regular bed, in a 1-story home with no open stairwells. The mother denied that he tried to leave the home by a door or window. The mother said he did not snore, nor thrashed or moved around in the bed, nor had daytime sleepiness. He did have night terrors as a young infant. She also denied any seizure-like activity or headaches currently. The past medical history was non-contributory. He had no seizures, attention deficit disorder and took no medications. He had been getting less sleep overall because of school and extra curricular activities for the past 2 months. The family history was negative for any sleep problems.

The pertinent physical exam showed a well-appearing male with normal vital signs and growth parameters in the 10-50%. His examination was normal including his neurological examination. The diagnosis of a healthy male with sleepwalking was made. The doctor counseled that this was a common problem and may or may not continue. He strongly encouraged good sleep hygiene including regular bedtimes and morning awakenings. He also counseled about a safe sleeping environment including having items picked up from the floor in the bedroom to avoid tripping. The family was to monitor the behavior and report if it was increasing or if dangerous behaviors were occurring.

Sleep disorders are common in all ages particularly sleep deprivation in our increasingly busy world. A review of health problems caused by inadequate sleep can be found here. Sleep problems are more common in patients with attention deficit hyperactivity disorder, epilepsy, headache and visual impairments. Sleep problems can cause cognitive and behavioral impairments including emotional regulation problems, increased seizures or headaches, and impaired attention and has been known to prolong recovery from various acquired brain injuries.

Somnambulism or sleepwalking is a parasomnia (which include confusional arousals, sleep terrors, nightmares, sleep paralysis, restless legs, etc.). It is a non-rapid eye movement (non-REM) sleep arousal disorder that occurs during slow wave sleep. Slow wave sleep predominates in the early part of sleeping (usually within 1-3 hours) and children have more slow wave sleep than adults which may be part of the reason it is seen more often in children. Patients with one parasomnia are at increased risk for others. The episodes can last from a few minutes to up to 30-40 minutes and the patient has amnesia for the event. Patients have ambulation or other complex behaviors after getting out of bed and appear confused/dazed (occasionally have agitation), might talk, mumble or give inappropriate answers, and eyes are open. They may have behaviors that are inappropriate such as urinating in the wrong place.

It is very uncommon for people to have significant problems due to somnambulism, however the biggest risk is injury. The true risk is unknown because sleepwalking is a difficult diagnosis to make and injuries are often minor or are not reported. Obviously patients can have more significant injuries if they were to accidentally fall from a height such as a bed, window or down stairs. An emergency room study of patients > 15 years of age, found only 11 trauma admissions were associated with somnambulism. Two patients were 16 years of age with one having a contusion and the other having several contusions and superficial cuts. Four patients required admission and none died.

Treatment is using appropriate safety measures such as gates, locking doors and windows while sleeping etc. For patients with known sleepwalking, avoiding sleep deprivation and medications that disturb sleep arousal such as alcohol, hypnotic and psychotropic medications is also advised. Avoiding sleeping environments which may arouse the patient from sleep such as loud, sudden noises is appropriate. Scheduled sleep awakening can be used for patients with nightly somnambulism. Overall outcome is difficult to determine. For many patients, it resolves, but for others it continues intermittently or more consistently.

Learning Point
Somnambulism has been noted as early as age 2 years. The most common age for somnambulism is ~10 years of age, with 14% experiencing it at some point by this age, and 29% experiencing it at least once during childhood.

According to a 2016 meta-analysis and systematic review of the medical literature, the prevalence rate within the last year of somnambulism is 5% in children and 1.5% in adults. The estimated life-time risk is 6.9%.

There is difficulty in diagnosing somnambulism. The sleepwalking may not be observable by others (parents, significant others) and they may not be sure what is going on nor can they actually confirm the neurological arousal state the patient is in. A sleep study can confirm the sleep state. Self-report obviously has problems as people report what they have been told by others, rely on observed minor injuries such as bruises/cuts and believe they have occurred because of somnambulism, or they observe the environment has been disordered (movement of items including furniture during the night) and they believe is due to somnambulism.

Questions for Further Discussion
1. How is insomnia or narcolepsy treated?
2. How do you counsel families about common infant sleeping problems?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.
Information prescriptions for patients can be found at MedlinePlus for this topic: Sleep Disorders

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Moreno MA. Sleep Terrors and Sleepwalking: Common Parasomnias of Childhood. JAMA Pediatr. 2015 Jul;169(7):704.

Maski K, Owens JA. Insomnia, parasomnias, and narcolepsy in children: clinical features, diagnosis, and management. Lancet Neurol. 2016 Oct;15(11):1170-81.

Stallman HM, Kohler M, Wilson A, Biggs S, Dollman J, Martin J, Kennedy D, Lushington K. Self-reported sleepwalking in Australian senior secondary school students. Sleep Med. 2016 Sep;25:1-3.

Sauter TC, Veerakatty S, Haider DG, Geiser T, Ricklin ME, Exadaktylos AK. Somnambulism: Emergency Department Admissions Due to Sleepwalking-Related Trauma. West J Emerg Med. 2016 Nov;17(6):709-712.

Stallman HM, Kohler M. Prevalence of Sleepwalking: A Systematic Review and Meta-Analysis. PLoS One. 2016 Nov 10;11(11):e0164769.

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa