Parasomnia
| Parasomnia | |
|---|---|
| Specialty | Sleep medicine, psychology  |
Parasomnias are a category of sleep disorders that involve abnormal movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or arousal from sleep. Most parasomnias are dissociated sleep states which are partial arousals during the transitions between wakefulness and NREM sleep, or wakefulness and REM sleep.
NREM Parasomnias
NREM parasomnias are arousal disorders that occur during stages 3 and 4 of NREM sleep—also known as slow wave sleep (SWS). They are caused by a physiological activation in which the patient’s brain exits from SWS and is caught in between a sleep and waking state. In particular, these disorders involve activation of the autonomic nervous system, motor system, or cognitive processes during sleep or sleep-wake transitions.[1]
NREM parasomnias are common during childhood but decrease in frequency with increasing age. They can be triggered in certain individuals by alcohol, sleep deprivation, physical activity, emotional stress, depression, medications, or a fevered illness. These disorders of arousal can range from confusional arousals, somnambulism, to night terrors. Other specific disorders include sleepeating, sleep sex, teeth grinding, rhythmic movement disorder, restless legs syndrome, and somniloquy.
Confusional arousals
With a prevalence of 4%, confusional arousals are not observed very often in adults; however, they are common in children.[2] Confusional arousals are occasional thrashings or inconsolable crying among children—they are characterized by movements in bed.
Sleepwalking (somnambulism)
Sleepwalking has a prevalence of 1-17% in childhood, with the most frequent occurrences around the age of eleven-twelve. About 4% of adults experience somnambulism. [3]
Sleep terrors (night terrors)
Sleep terrors is the most disruptive arousal disorder since it may involve loud screams and panic; in extreme cases, it may result in bodily harm or property damage by running about or hitting walls. Unfortunately, all attempts to console the individual are futile and may prolong or intensify the victim’s confused state. Usually the victim experiences amnesia after the event but it may not be complete amnesia. Up to 3% of adults suffer from sleep terrors and exhibited behavior of this parasomnia can range from mild to extremely violent. [4]
REM Parasomnias
REM Sleep Behavior Disorder (RBD) is the most common REM sleep parasomnia in which muscle atonia is absent. This allows the individual to act out their dreams and may result in repeated injury-- bruises, lacerations and fractures-- to themselves or others. Patients may take self-protection measures by tethering themselves to bed, using pillow barricades or sleeping in an empty room on a mattress. [5] Demographically, 90% of RBD patients are males, and most are older than 50 years of age. [6]
Acute RBD
Occurs mostly as a result of a side-effect in prescribed medication- usually antidepressants.
Chronic RBD
Is idiopathic or associated with neurological disorders. There is a growing association of chronic RBD with neurodegenerative disorders – Parkinson’s disease, multiple system atrophy (MSA) or dementia-- as an early indicator of these conditions by as much as 10 years. Patients with narcolepsy also are more likely to develop RBD.
See also
References
- Mahowald & Schenck. Insights from studying human sleep disorders. Nature (2005); 437(7063):1279-85.
- Bassetti et al., Lancet (2000); 356: 484–485
Notes
Further reading
- Siegel, Ronald (1992). Fire in the Brain: Clinical Tales of Hallucination.
- Warren, Jeff (2007). The Head Trip: Adventures on the Wheel of Consciousness. ISBN 978-0679314080.