Somniloquy

Somniloquy or sleep-talking is a parasomnia that refers to talking aloud while asleep. It can be quite loud, ranging from simple sounds to long speeches, and can occur many times during sleep. Listeners may or may not be able to understand what the person is saying. As with sleepwalking and night terrors, sleeptalking usually occurs during delta-wave NREM sleep stages or temporary arousals from them.

Furthermore, it can also occur during REM sleep, at which time it represents a motor breakthrough (see sleep paralysis) of dream speech: words spoken in a dream are spoken out loud. Depending on its frequency, this may or may not be considered pathological. All motor functions are typically disabled during REM sleep; thus, motoric i.e. verbal elaboration of dream content could be considered REM behavior disorder (see below).

Sleep-talking can occur by itself or as a feature of another sleep disorder such as:
 * Rapid eye movement behavior disorder (RBD) - loud, emotional or profane sleep talking
 * Sleepwalking
 * Night terror - intense fear, screaming, shouting
 * Sleep-related eating disorder (SRED)

Sleep-talking is very common and is reported in 50% of young children, with most of them outgrowing it by puberty, although it may persist into adulthood (about 4% of adults are reported to talk in their sleep). It appears to run in families. Sleep-talking can be associated with a fever.

In 1966, researchers K. Abe and M. Shimakawa worked to find links between heredity and Somniloquy. Their research suggests the following:


 * Sleep-talking parents are more likely to have children who sleep-talk
 * Sleep talking can still occur when neither parent has a history of sleep talking, though this is far less common
 * A large portion of parents begin to sleep-talk later in life without any prior history of sleep-talking during childhood or adolescence

Sleep-talking by itself is harmless; however, it can wake up others and cause them consternation&mdash;especially when misinterpreted as conscious speech by an observer. If the sleep-talking is dramatic, emotional, or profane it may be a sign of another sleep disorder (see above). Sleep-talking can be monitored by a partner or by using an audio recording device; devices which remain idle until detecting a sound wave are ideal for this purpose. Polysomnography (sleep recording) shows episodes of sleep talking that can occur in any stage of sleep.