Parasomnias
Section snippets
Disorders of Arousal (from NREM Sleep)
Confusional arousals, sleepwalking, and sleep terrors comprise the disorders of arousal. These behaviors most often results from arousals or partial arousals during slow wave sleep in the first third of the night and are differentiated from one another by the character of the accompanying behavior. In this class of parasomnia, the patient usually appears awake and is amnestic to the event.1 Disorders of arousal, like all parasomnias, may be triggered by another sleep disorder, such as
REM Sleep Behavior Disorder (Including Parasomnia Overlap Disorder and Status Dissociatus)
This parasomnia was formally identified in humans by Carlos Schenck in 1986 in a series of 5, and then 10 patients. However, clinical aspects have been described since 1966.23 In patients with REM sleep behavior disorder (RBD), abnormal behaviors that disrupt sleep or cause injury are a result of dream enactment.1 The diagnosis of RBD is of utmost importance due to its association with neurodegenerative diseases, specifically, the alpha synnucleopathies: Parkinson's disease, dementia with Lewy
Recurrent Isolated Sleep Paralysis
Recurrent isolated sleep paralysis is a REM sleep parasomnia consisting of the inability to move voluntarily upon sleep onset (hypnagogic) or during awakenings from sleep (hypnapompic) in the absence of a diagnosis of narcolepsy where this finding is part of the tetrad of symptoms.1
Nightmare Disorder
Nightmare disorder is a REM sleep parasomnia characterized by the recurrence of particularly disturbing nightmares.
Sleep-Related Dissociative Disorders
This parasomnia is defined as dissociative episodes after an awakening form sleep.
Epidemiology
Prevalence is unknown; there is a female predilection and onset can be in childhood to middle adulthood.1
Pathophysiology
As with daytime dissociation, this type of behavior results when there is an absence of normal integration of thoughts, feelings, and experiences into consciousness and memory.52
Clinical Presentation
The behaviors of sleep-related dissociative disorders occur during an actual awakening, although the patient is amnestic to them.
Sleep-Related Enuresis
Sleep-related enuresis is recurrent involuntary voiding occurring twice weekly in patients greater than 5 years of age and is divided into primary and secondary based on the clinical presentation.1
Sleep-Related Groaning
Sleep-related groaning, also known as catathrenia, is chronic usually nightly moaning, groaning, or other monotonous sound in the absence of any other vocalization, motor behavior, associated dreaming, or sleep disordered breathing.1
Exploding Head Syndrome
Initially described as a “snapping of the brain” in 1920, exploding head syndrome is a sensation of a sudden loud noise or explosive feeling within the head upon falling asleep or during an awakening from sleep.58
Sleep-Related Hallucinations
Sleep-related hallucinations are hallucinations that occur upon falling asleep (hypnagogic) or upon awakening (hypnapompic).1
Sleep-Related Eating Disorder
Sleep-related eating disorder (SRED) results in recurrent episodes of arousals from sleep with involuntary eating or drinking.1
Differential Diagnosis of Parasomnia
Obstructive sleep apnea may present as parasomnia in multiple ways. Disorders of arousal, nocturnal dissociative states, and sleep-related eating disorder may result from respiratory event related arousals from NREM sleep.1 If sleep disordered breathing is severe and results in arousals from REM sleep, “pseudo RBD” can result with postarousal, dream-enacting behaviors with locomotion, agitation, and violence.70 Conversely, during the treatment of obstructive sleep apnea, slow wave sleep rebound
Summary and Recommendations
Parasomnias are a heterogeneous group of abnormal behaviors during sleep. Although they may be benign and transient (especially in children), they may be persistent and result in significant injury, sleep disruption, daytime impairment, general health problems, and social consequences. In addition, parasomnias may be the presenting symptom of another sleep disorder and therefore necessitate thorough investigation. The detection of REM sleep behavior disorder is of particular importance due to
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