Parasomnia means: It is possible to speak a few words or a whole speech while sleeping. It involves going on nocturnal walks, and it is common in children. Similar to severe nightmares, sleep terrors can be accompanied with extreme fear and screaming. Night terrors can occur up to two weeks after the surgery and affect 15% of children. Although they appear awake, many children are deep asleep and won’t respond to being shook or spoken to. The REM behavior disorder is when they act out their dreams in rapid eye movement (REM) sleep. It is more common among older men, who can usually recall the dreams. Treatment is by tranquilizer or antidepressant. A condition where people are unable to sleep at night, nocturnal disorder can be described as a disorder in which they relive incidents of physical or sexual abuse.
(in Medical Dictionary)

What else does Parasomnia mean?

Parasomnia is a sleep disorder that causes strange or hazardous events to interrupt sleep. Parasomnias can include: sleep walking somnambulism and sleepwalking somnambulism.
(in Medical Dictionary)

One of the many sleep disorders, including sleepwalking or night terrors, enuresis and nocturnal seizures.
(in Merlin Dictionary)