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 primary criteria used to identify REM are the change in electrical activity, measured by EEG, and loss of muscle tone, interspersed with bouts of twitching in phasic REM. The amount of REM sleep and cycling varies among animals; predators experience more REM sleep than prey. Larger animals also tend to stay in REM for longer, possibly because higher thermal inertia of their brains and bodies allows them to tolerate longer suspension of thermoregulation. The period (full cycle of REM and non-REM) lasts for about 90 minutes in humans, 22 minutes in cats, and 12 minutes in rats. In utero, mammals