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.
For many of these disorders, history and physical examination can confirm the diagnosis.
Sitting, walking, or other complex behavior occurs 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 1st-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 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, 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 0.5 to 2 mg po, at bedtime typically help if behavioral measures are not completely effective.
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 after arousal from N3 sleep; thus, they do not represent nightmares. In adults, sleep terrors can be associated with mental difficulties or alcoholism.
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 1 to 2 mg, diazepam 2 to 5 mg) at bedtime may help. Adults may benefit from psychotherapy or drug treatment.
Verbalization (sometimes profane) and often violent 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.
This disorder is more common among the elderly, particularly those with CNS degenerative disorders (eg, Parkinson or Alzheimer disease, vascular dementia, olivopontocerebellar degeneration, 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). Cause is usually unknown. Some patients develop Parkinson disease years after REM sleep behavior disorder is diagnosed.
Diagnosis 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.
Treatment is with clonazepam 0.5 to 2 mg po at bedtime. Most patients need to take the drug indefinitely to prevent recurrences; potential for tolerance or abuse is low. 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 elderly patients.
Diagnosis 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. Numerous drugs (eg, quinine, Ca and Mg 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.