Sleep Disorder – Parasomnia
A parasomnia is any sleep disorder such as sleepwalking, sleepeating, sleep sex, teeth grinding, night terrors, rhythmic movement disorder, REM behaviour disorder, restless legs syndrome, and somniloquy, characterized by partial arousals during sleep or during transitions between wakefulness and sleep. Parasomnias are often associated with stress and depression, and biological factors may also be involved. Many parasomnias are more common in children than in adults.
Unlike dyssomnias, parasomnias do not involve abnormalities of the mechanisms generating sleep-wake states, nor of the timing of sleep and wakefulness. Rather, parasomnias represent the activation of physiological systems at inappropriate times during the sleep-wake cycle. In particular, these disorders involve activation of the autonomic nervous system, motor system, or cognitive processes during sleep or sleep-wake transitions.
Many parasomnias, such as sleepwalking, have serious risks. For example, a person with REM behavior disorder, while trying to swing a tennis racket in a dream, can potentially injure their bedmate. People with night terrors can prevent others from sleeping well, as well as waking themselves up. For these reasons, parasomniacs sometimes need medical treatment.
Diagnosis is relatively easy when all the symptoms of Parasomnia are present. But if the sleep attacks are isolated and cataplexy is mild or absent, diagnosis is more difficult.
Two tests that are commonly used in diagnosing Parasomnia are the polysomnogram and the multiple sleep latency test. These tests are usually performed by a sleep specialist. The polysomnogram involves continuous recording of sleep brain waves and a number of nerve and muscle functions during nighttime sleep. When tested, people with Parasomnia fall asleep rapidly, enter REM sleep early, and may awaken often during the night. The polysomnogram also helps to detect other possible sleep disorders that could cause daytime sleepiness.
For the multiple sleep latency test, a person is given a chance to sleep every 2 hours during normal wake times. Observations are made of the time taken to reach various stages of sleep. This test measures the degree of daytime sleepiness and also detects how soon REM sleep begins. Again, people with Parasomnia fall asleep rapidly and enter REM sleep early.
The drowsiness is normally treated using amphetamine-like stimulants such as methylphenidate, racemic amphetamine, dextroamphetamine, and methamphetamine, or modafinil, a new stimulant with a different pharmacologic mechanism.
Other medications used are codeine and selegiline. Another drug that is used is atomoxetine (Strattera), a non-stimulant and Norepinephrine uptake inhibhitor (NRI), that has little or no abuse potential. In many cases, planned regular short naps can reduce the need for pharmacological treatment of the EDS to a low or non-existent level. Cataplexy is frequently treated with tricyclic antidepressants such as clomipramine, imipramine, or protriptyline. Venlafaxine, a newer antidepressant which blocks the reuptake of serotonin and norepinephrine, has shown usefulness in managing symptoms of cataplexy. Gamma-hydroxybutyrate (GHB), a medication recently approved by the US Food and Drug Administration, is the only medication specifically indicated for cataplexy. Gamma-hydroxybutyrate has also been shown to reduce symptoms of EDS associated with Parasomnia. While the exact mechanism of action is unknown, GHB is thought to improve the quality of nocturnal sleep.
Treatment is tailored to the individual based on symptoms and therapeutic response. The time required to achieve optimal control of symptoms is highly variable, and may take several months or longer. Medication adjustments are also frequently necessary, and complete control of symptoms is seldom possible. While oral medications are the mainstay of Parasomnia treatment, lifestyle changes are also important. The main treatment of excessive daytime sleepiness in Parasomnia is with a group of drugs called central nervous system stimulants. For cataplexy and other REM-sleep symptoms, antidepressant medications and other drugs that suppress REM sleep are prescribed.