Rapid eye movement sleep behavior disorder Rapid eye movement sleep behavior disorder Rapid eye movement sleep behavior disorder (RBD) is a sleep disorder (more specifically a parasomnia) in which people act out their dreams. It involves abnormal behavior during the sleep phase with rapid eye movement (REM) sleep. The major feature of RBD is loss of muscle atonia (i.e., the loss of paralysis) during otherwise intact REM sleep (during which paralysis is not only normal but necessary). REM sleep is the stage of sleep in which most vivid dreaming occurs. The loss of motor inhibition leads to a wide spectrum of behavioral release during sleep. This
Rapid eye movement sleep falling asleep. Cycles of about 90 minutes each follow, with each cycle including a larger proportion of REM sleep. (The increased REM sleep later in the night is connected with the circadian rhythm and occurs even in people who didn't sleep in the first part of the night.) In the weeks after a human baby is born, as its nervous system matures, neural patterns in sleep begin to show a rhythm of REM and non-REM sleep. (In faster-developing mammals this process occurs in utero.) Infants spend more time in REM sleep than adults. The proportion of REM sleep then decreases