Parasomnias & Movement Disorders
Parasomnias are undesirable physical events, most commonly movements or speech, that disrupt sleep. Most of the time, they are not dangerous even if they are disturbing or frustrating to the sleeper. Often, the sleeper is unaware of the movements or speech and they are annoying to the bed partner. These disorders are typically classified by the sleep stage in which they occur, either REM or non-REM sleep.
REM-related parasomnias occur more frequently in the second half of the night, when there is more REM sleep. The sleeper is more often aware of events, like sleep paralysis. Acting out dreams can be a risk to the sleeper, for example running into a wall dreaming that they are running from a bear, or to the bed partner, dreaming that they must fight off the bear.
Non-REM parasomnias are often described as disorders of arousal since the sleeper may be partially awake during the event. They occur more frequently in the first half of the night. While the sleeper’s eyes may be open and they seem to have purposeful movement, they may not respond and usually have no memory of the event. This includes night terrors and sleepwalking.
The group of other parasomnias can occur at any time, and include bed-wetting, exploding head syndrome, and sleep-related eating disorder.
All parasomnias can be aggravated by sleep deprivation, stress, and neurologic disorders, as well as disturbed sleep either from external triggers, like medications, or other sleep conditions like sleep apnea. If correction of the aggravating factors does not improve the symptoms, laboratory sleep testing is typically performed to understand the condition and evaluate for potential triggers.