Nocturnal Myoclonus Syndrome

**Definition:** Excessive periodic leg movements during sleep that cause micro-arousals and interfere with the maintenance of sleep. This condition induces a state of relative sleep deprivation which manifests as excessive daytime hypersomnolence. The movements are characterized by repetitive contractions of the tibialis anterior muscle, extension of the toe, and intermittent flexion of the hip, knee and ankle. (Adams et al., Principles of Neurology, 6th ed, p387)

**Tree numbers:** - C10.886.425.800.600 - C10.886.659.618

**Synonyms:** - Excessive Periodic Sleep-Related Leg Movements - Periodic Leg Movements, Excessive, Sleep-Related - Periodic Limb Movement Disorder - Periodic Movement Disorder, Sleep - Sleep Disorder, Periodic Movements - Sleep-Related Periodic Leg Movements, Excessive - Sleep Myoclonus Syndrome