NCIt definition : A group of sleep disorders causing disruption of sleep. Representative examples include
nightmare disorders, sleep terror disorders, sleepwalking, and restless leg syndrome.;
Alternative definition : NCI-GLOSS: An abnormal disruption of sleep, such as sleep walking, sleep talking,
nightmares, bedwetting, sleep apnea (problems with breathing that cause loud snoring),
or nighttime seizures.; NICHD: Abnormal behavior or movements during sleep.;