Final answer:
Parasomnias are sleep disorders that include unwanted, disruptive motor activity or experiences such as sleepwalking, restless leg syndrome, night terrors, and REM sleep behavior disorder.
Step-by-step explanation:
The group of sleep disorders in which unwanted, disruptive motor activity and/or experiences during sleep play a role is known as parasomnias. These disorders can manifest during different sleep phases, including REM or NREM sleep. Some common examples include sleepwalking, restless leg syndrome, and night terrors. A notable parasomnia occurring during REM sleep is REM sleep behavior disorder (RBD), where the typical muscle paralysis does not take place, leading to active and sometimes violent movements during sleep.