Parasomnias are undesirable behaviors that occur during entry into sleep, during sleep, or during arousal from sleep. Diagnosis is clinical. Treatment may include drugs and psychotherapy.
(See also Approach to the Patient With a Sleep or Wakefulness Disorder.)
For many of these disorders, history and physical examination can confirm the diagnosis.
Somnambulism
Patients may mumble repetitiously, and some injure themselves on obstacles or stairs. Patients do not remember dreaming after awakening or the following morning and usually do not remember the episode.
Treatment of somnambulism is directed at eliminating the triggers for these episodes. It also involves protecting patients from injury—eg, by using electronic alarms to awaken patients when they leave the bed, using a low bed, installing door alarms, and removing sharp objects from the bedside and obstacles from the bedroom. Occasionally, patients are advised to sleep on mattresses on the floor.
Sleep (night) terrors
During the night, patients suddenly scream, flail, and appear to be frightened and intensely activated. Episodes can lead to sleepwalking. Patients are difficult to awaken. Sleep terrors are more common among children and occur when children are partially aroused or are awakened from N3 sleep; thus, they do not represent nightmares. In adults, sleep terrors can be associated with psychologic problems or alcohol use disorder.
Nightmares
Children are more likely to have nightmares than adults. Nightmares occur during REM sleep, more commonly when fever, excessive fatigue, or mental distress is present or after alcohol has been ingested.
Treatment of nightmares is directed at any underlying mental distress.
Rapid eye movement (REM) sleep behavior disorder
Verbalization (sometimes profane) and often aggressive movements (eg, waving the arms, punching, kicking) occur during REM sleep. These behaviors may represent acting out dreams by patients who, for unknown reasons, do not have the atonia normally present during REM sleep. Patients are aware of having vivid dreams when they awaken after the behaviors.
REM sleep behavior disorder is more common among older people, particularly those with degenerative disorders of the central nervous system (CNS)—eg, Parkinson disease, Alzheimer disease, vascular dementia, multiple system atrophy, progressive supranuclear palsy. Similar behavior can occur in patients who have narcolepsy or who take norepinephrinedementia with Lewy bodies. Some patients develop Parkinson disease years after REM sleep behavior disorder is diagnosed.
Diagnosis of REM sleep behavior disorder may be suspected based on symptoms reported by patients or the bed partner. Polysomnography can usually confirm the diagnosis. It may detect excessive motor activity during REM; audiovisual monitoring may document abnormal body movements and vocalizations. A neurologic examination is done to rule out neurodegenerative disorders. If an abnormality is detected, CT or MRI may be done.
Bed partners should be warned about the possibility of harm and may wish to sleep in another bed until symptoms resolve. Sharp objects should be removed from the bedside.
Sleep-related leg cramps
Muscles of the calf or foot muscles often cramp during sleep in otherwise healthy middle-aged and older patients.
Diagnosis of sleep-related cramps is based on the history and lack of physical signs or disability.
Prevention includes stretching the affected muscles for several minutes before sleep. Stretching as soon as cramps occur relieves symptoms promptly and is preferable to drug treatment.
