**2. Causes of parasomnias**

Parasomnias occur due to abnormal transitions between the three primary states of being wake, rapid eye movement (REM) sleep, and non rapid eye movement (NREM) sleep. These different states may overlap or intrude into one another, and it is the overlap of wakefulness and NREM sleep that gives rise to confusional arousals, and the intrusion of REM sleep into waking that produces REM sleep behaviour disorder (Matwiyoff et al, 2010).

Parasomnias may have genetic basis, but occurrence is usually triggered by heavy physical activity, febrile illness, sleep deprivation, excessive caffeine drinks, hypnotics, and emotional stress. Intake of alcohol increased occurrence of confusional arousal, night terror, and sleepwalking, while heavy intake of caffeinated drink increased occurrence of sleep walking in a population study (Oluwole, 2010).

Parasomnias 151

All parasomnias more commonly affect persons who have breathing disorders during sleep. Polysomnography is appropriate for any patient with symptoms or signs of obstructive sleep apnea, such as daytime hypersomnolence, nocturnal hypoxia, loud snoring and increased neck circumference. REM behavior disorder often occurs concomitantly with degenerative neurologic illnesses that may require further evaluation. In adults, the onset of arousal disorders such as somnambulism and night terrors may reflect underlying neurologic disease. Thus, neurologic evaluation, including imaging of the central nervous

Diagnosis of parasomnias relies on a comprehensive clinical evaluation. Additional testing with polysomnogram and time-synchronized video recording may be indicated for cases that are associated with very frequent episodes, complaints of excessive sleepiness, unusual presentation, or injury to the individual or bed partner. A formal laboratory sleep study or polysomnogram with an expanded electroencephalographic montage can help distinguish among non-REM and REM parasomnias and nocturnal seizures. The latter may manifest clinically as arousals from sleep associated with vocalization and/or complex behaviours

Generally parasomnias, particularly those that are associated with non-REM sleep are commoner in childhood, but studies showed that non- REM parasomnias are not uncommon in adults. Parasomnias have been reported in approximately 4% of the adult

Prevalence of sleepwalking, which consists of a series of complex behaviours that are initiated during slow wave sleep and result in walking during sleep, varies from 10 per 1,000 to 145 per 1,000. In a population of adults prevalence of sleep walking was 20 per 1,000

Sleep terrors, which are characterized by sudden arousal from slow wave sleep with a piercing scream or cry, accompanied by autonomic and behavioral manifestations of intense fear, are a common parasomnia in childhood. Its prevalence in children varies from 30% to 398 per 1,000, but prevalence of 22 per 1,000 was found in an adult population (Kales et al.,

Nightmares are frightening dreams that usually awaken the sleeper from REM sleep. Between 10 and 20% of children experience nightmares that disturb their parents while 50% of adults have occasional nightmares and 1% have one or more nightmares per

Sleep paralysis consists of a period of inability to perform voluntary movements at sleep onset, hypnagogic or predormital form, or upon awakening, either during the night or in the morning, hypnopompic or postdormital. Lifetime prevalence of isolated sleep paralysis in

Sleep enuresis is characterized by recurrent involuntary micturition that occurs during sleep. In children prevalence of sleep enuresis could be up to 250 per 1,000. In adults

the general population in Germany and Italy was shown to be 62 per 1,000.

prevalence of nocturnal enuresis varies from 2 to 38 per 1,000.

**3. Diagnosis of parasomnias** 

(Farid et al., 2004).

**4. Epidemiology** 

population (Ohayon et al., 2000).

(Guilleminault et al., 2003).

1980).

week.

system, may be indicated (Bornemann et al., 2006).


Table 1. The International Classification of Sleep Disorders classification of parasomnias

Heredity was described for many forms of parasomnias but detailed genetic studies are lacking. The composition of non-REM and REM sleep was shown to have genetic roots. Especially the amount of slow-wave sleep was recently shown to be genetically predisposed by a specific gene, the retinoid acid receptor beta encoding gene (Young, 2008; Maret et al., 2005).

**Arousal disorders** 

Sleepwalking Sleep terrors

Sleep starts Sleep-talking

Nightmares Sleep paralysis

Confusional arousals

Nocturnal leg cramps

**Sleep-wake transition disorders** 

**Parasomnias usually associated with REM sleep** 

Impaired sleep-related penile erections

Sleep-related abnormal swallowing syndrome

Sudden unexplained nocturnal death syndrome

Congenital central hypoventilation syndrome

Table 1. The International Classification of Sleep Disorders classification of parasomnias

Heredity was described for many forms of parasomnias but detailed genetic studies are lacking. The composition of non-REM and REM sleep was shown to have genetic roots. Especially the amount of slow-wave sleep was recently shown to be genetically predisposed by a specific gene, the retinoid acid receptor beta encoding gene (Young, 2008; Maret et al.,

Sleep-related painful erections

Nocturnal paroxysmal dystonia

Sudden infant death syndrome Benign neonatal sleep myoclonus

REM sleep sinus arrest REM sleep behavior disorder

**Other parasomnias** 

Sleep bruxism Sleep enuresis

Primary snoring Infant sleep apnea

2005).

Rhythmic movement disorder
