Парасомнії

Sitting, walking, or other complex behaviors occur during sleep, usually with the eyes open but without evidence of recognition. Somnambulism is most common during late childhood and adolescence and occurs after and during arousal from nonrapid eye movement (NREM) stage N3 sleep. Prior sleep deprivation and poor sleep hygiene increase the likelihood of these episodes, and risk is higher for first-degree relatives of patients with the disorder. Episodes may be triggered by factors that cause arousals during sleep (eg, caffeine, other stimulant drugs and substances, behaviors that disrupt sleep) or that enhance N3 sleep (eg, prior sleep deprivation, excessive exercise).

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.

Benzodiazepines, particularly clonazepam at bedtime, can help if behavioral measures are not completely effective, but these medications have significant adverse effects.

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.

For children, parental reassurance is often the mainstay of treatment. If daily activities are affected (eg, if school work deteriorates), intermediate- or long-acting oral benzodiazepines (eg, clonazepam, diazepam) at bedtime may help, but these medications have significant adverse effects. Adults may benefit from psychotherapy or medications.

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.

Verbalization (sometimes profane) and often aggressive movements (eg, waving the arms, punching, kicking) occur during REM sleep in patients with REM behavior disorder. 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 adults, 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 norepinephrine reuptake inhibitors (eg, atomoxetine, reboxetine, venlafaxine). In patients with REM sleep behavior disorder, synuclein accumulates in neurons, as occurs in neurodegenerative disorders such as Parkinson disease, multiple system atrophy, and dementia with Lewy bodies. Patients may 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 performed to rule out neurodegenerative disorders. If an abnormality is detected, CT or MRI may be performed.

Treatment of REM sleep behavior disorder is with clonazepam at bedtime (1). Most patients need to take the drug indefinitely to prevent recurrences; potential for tolerance or abuse is low. An alternative is melatonin 3 to 18 mg (but an optimal dosage is not known).

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.

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 (2). Stretching as soon as cramps occur relieves symptoms promptly and is preferable to pharmacotherapy.

Numerous agents (eg, quinine, calcium and magnesium supplements, diphenhydramine, benzodiazepines, mexiletine) have been used; none is likely to be effective, and adverse effects may be significant (particularly with quinine and mexiletine). Avoiding caffeine and other sympathetic stimulants may help.