Sleep Disorders and Parasomnias
Rhythmic Movement Disorder
Rhythmic movement disorder occurs mostly in children under age 1. A child may lie flat, lift the head or upper body, and then forcefully hit his or her head on the pillow. Rhythmic movement disorder, which also has been called "head banging," also can involve movements such as rocking on hands and knees. The disorder usually occurs just before a person falls asleep.
Sleep talking is a sleep-wake transition disorder. Although it usually is harmless, sleep talking can be disturbing to sleep partners or family members who witness it. Talk that occurs during sleep can be brief and involve simple sounds, or it can involve long speeches by the sleeper. A person who talks during sleep typically has no recollection of the actions. Sleep talking can be caused by external factors, including fever, emotional stress, or other sleep disorders.
Nocturnal Leg Cramps
Nocturnal leg cramps are sudden, involuntary contractions most commonly of the calf muscles during the night or periods of rest. The cramping sensation may last from a few seconds to 10 minutes, but the pain from the cramps may linger for a longer period. Nocturnal leg camps tend to be found in middle-aged or older populations, but people of any age can have them. Nocturnal leg cramps differ from restless legs syndrome, because the latter usually does not involve cramping or pain. The cause of nocturnal leg cramps is not known. Some cases of the disorder can occur without a triggering event, while other causes of leg cramps may be linked to prolonged sitting, dehydration, an overexertion of the muscles, or structural disorders (such as flat feet). Muscle-stretching, exercise, and adequate water intake may help prevent leg cramps.
People with sleep paralysis are not able to move their body or limbs either when falling asleep or waking up. Brief episodes of partial or complete skeletal muscle paralysis can occur during sleep paralysis. Sometimes sleep paralysis runs in families, but the cause of sleep paralysis is not known. This disorder is not harmful, but people experiencing sleep paralysis often are fearful, because they do not know what is happening. An episode of sleep paralysis often is terminated by sound or touch. Within minutes, the person with sleep paralysis is able to move again. It may occur only once in your lifetime or can be a recurrent phenomenon.
Impaired Sleep-Related Erections
This disorder occurs among men who are unable to sustain a penile erection during sleep that would be sufficiently rigid enough to engage in sexual intercourse. Men usually experience erections as a part of REM sleep, and impaired sleep-related erections may indicate erectile dysfunction.
Sleep-Related Painful Erections
Erections are a normal component of REM sleep for men. In rare cases, however, erections become painful and cause a man to wake up. The treatment of sleep-related painful erections may involve drugs that suppress REM sleep (some antidepressants, for example).