Sleepwalking Disorders: A Genetic Analysis

Sleepwalking

Parasomnias are a sub-category of sleep disorder that involve strange and abnormal behaviors, movements and emotions that can occur during or in between sleep stages. Somnambulism, or sleepwalking disorder, is a type of parasomnia that is relatively common in childhood, but tends to subside into adulthood (Perogamvros, 2015). Sleepwalking is characterized by behaviors that are initiated during arousal from slow-wave sleep (Perogamvros, 2015). The behaviors can be simple, complex, and in some cases nonsensical or dangerous in nature. Sleepwalking walking episodes are most likely to occur during times of psychological or physiological stress, and can be triggered by various genetic, environmental and external factors (Gilles & Cataldo

& Atkins, 2012).
Sleepwalking episodes often occur early in the night, usually within a couple hours after sleep onset (Kales,1987). An episode typically lasts less than 10 minutes, and patients frequently experience confusion upon awakening with no recollection of the events that occurred during the episode (Kales,1987). An individual who is sleepwalking may display a variety of behaviors that can be simple, complex or aggressive in nature during an episode (Mume, 2010). During mild episodes behaviors can range from simply sitting up in bed and looking around, to simply fidgeting with the blankets and sheets. In more severe cases of sleepwalking an individual is capable of getting out of bed, leaving rooms and buildings, walking up and down stairs, and other complex activities such as cooking or eating (Szelenberger, 2005). Patients in general carry out the behavior with a blank expression and appear indifferent or un-reactive to the environment, showing low levels of awareness (Kales,1987). Sleepwalkers usually have some skill in moving around objects, however their behaviors in general may appear clumsy or purposeless (Kales,1987). Slow wave sleep are stage 3 and stage 4 of non-rapid eye movement (NREM) sleep combined (McCrae, 2009). Sleepwalkers may show impaired judgment, as demonstrated by difficulty in waking the person up (Szelenberger, 2005). The person also experiences amnesia following the event, and a brief period of confusion upon fully awakening (Szelenberger, 2005). Often the sleepwalker will either return to bed or fall asleep in a new area with no memory as to how they got there (Gilles, 2003).
Diagnosing sleepwalking disorder can be tricky, as the line that separates periodic sleepwalking from sleepwalking disorder is not clearly defined (Gilles, 2003).

Diagnosis through interviews are of little benefit as individuals rarely have any recollection of the activity that occurred during the episode (Gilles, 2003). According to the diagnostic criteria for sleepwalking disorder, an individual must experience a significant social or occupational impairment connected to the sleepwalking in order for a diagnosis of sleepwalking disorder to be made (Gilles, 2003). The diagnosis criteria also requires that the patient be checked to show no signs of dementia or other physical disorders (Szelenberger, 2005). Sleepwalking disorder can also be difficult to distinguish from sleep terrors, as both disorders involve motor movement, difficulty awakening, and the patient has no recollection of the event afterwards (Gilles, 2003). The main distinction between the two is that someone with sleep terror disorder will show signs of intense fear and panic through their behavior, such as screaming (Gilles, 2003). An accurate method for diagnosing sleepwalking disorder is through polysomnography, a technique that involves monitoring brain wave activity, breathing, heart rate and other vital signs by connecting electrodes to different parts of the body while the patient is asleep (Gilles,

2003).
Studies on sleepwalking have identified genetic, developmental, and psychological factors that can cause sleepwalking (Kale, 1987).

Family history of sleepwalking was confirmed in 80% of individuals with sleepwalking disorder and is ten times more likely to occur than in the general public(Kale, 1987). Sleepwalking episodes can be triggered by fevers, which directly affect the nervous system (Gilles, 2003). Alcohol use, sleep deprivation, pregnancy, menstruation, hormonal changes in adolescents and intense stress can also trigger episodes of sleepwalking (Gilles, 2003). Some medications have also been known to trigger sleepwalking episodes in individuals such as anti-anxiety or sleep inducing drugs, anti seizure medications, anti-arrhythmic heart medication (Gilles, 2003). Drugs used to treat psychosis (neuroleptics), increase sleep or relaxation (hypnotics), or treat allergies (antihistamines) can also trigger sleep walking episodes in individuals (Gilles & Cataldo & Atkins, 2012). Other medical conditions such as gastroesophageal reflux, night seizures, night asthma, night arrhythmia, and psychiatric disorders, such as panic attacks, can increase the likelihood of sleepwalking (Gilles & Cataldo & Atkins,

2012).
The most important consideration in taking care of individuals that sleepwalk is prevention of accidental injury. Individuals with sleepwalking disorder can take specific precautions to prevent injury, such as buying latches for doors and windows, or making sleep accommodations on the ground floor of their house (Kale, 1987). Even though most sleepwalkers are harmless, behaviors can become aggressive or dangerous to themselves and to others. On rare occasions a sleepwalker can become violent and aggressive towards a bystander if their path is blocked or if they try to act out a dream or a nightmare, in which case a doctor should be consulted first for a complete assessment (Gilles & Cataldo & Atkins, 2012).
Treatment for sleepwalking is often unnecessary especially if the episodes are mild, uncommon, and pose no danger to the patient or others (Gilles, 2003). Most cases of sleepwalking subside on their own overtime without treatment, especially during childhood (Gilles & Cataldo & Atkins, 2012). Most individuals seek professional help if the episodes persist for years into adulthood, or if the episodes are violent in nature and pose a threat to injury (Gilles, 2003). Adults whose sleepwalking episodes are triggered by stress can benefit from stress management, biofeedback training, and relaxation exercise techniques (Gilles, 2003). Hypnosis is also a technique that has been used to help sleepwalkers wake up once their feet have touched the ground. (Gilles, 2003). Individuals with underlying psychological issues that are contributing to their sleep problems can benefit from psychotherapy sessions, especially if the individual experiences frequent episodes that persist for several years from adolescence into adulthood and their family's history is negative for sleepwalking (Gilles, 2003).
New studies have explored the idea that abnormal sleep behaviors found in sleepwalking and other parasomnias, are an expression of increased activity in the brain's reward system during sleep ( Perogamvros, 2015). Since sleepwalking is predominant during NREM (no rapid eye movement) sleep, researchers experimented to see if exploratory excitability was linked to was linked to changes in NREM sleep patterns (Perogamvros, 2015). The result of the experiment suggests that patients experiencing parasomnia might share the same the same waking personality traits that are associated with reward related brain functions, providing evidence that reward seeking functions in the brain are active during sleep (Perogamvros, 2015).