Periodic limb movements during sleep

Similar to RLS, periodic limb movements in sleep (PLMS) is a sleep disorder in which people move their limbs (particularly the legs) during sleep. In PLMS, a person involuntarily twitches their legs every 20 to 40 seconds while sleeping. The difference between PLMS and RLS is that PLMS patients do not always feel the crawling uncomfortable sensations that make them want to move their legs. The limb movements in PLMS often occur during sleep while the person is completely unaware of them. However, occasionally PLMS can cause the person to... 

Periodic limb movements in sleep (PLMS)—A sleep disorder in which people move their limbs (particularly the legs) during sleep. 

Periodic limb movement is characterized by periodic episodes of repetitive and highly stereotyped limb movements that occur during sleep (12). It is reported to affect up to 34% of patients over age 60 years, and 1-15% of patients with insomnia. Movements are associated with partial awakening or arousals. Patients with isolated periodic limb movements in sleep (PLMS) without RLS may be asymptomatic. 

Presence of periodic limb movements (during wakefulness or sleep)... 

Parrino L, Boselli M, Buccino GP, Spaggiari MC, Di Giovanni G, Terzano MG (1996) The cyclic alternating pattern plays a gate-control on periodic limb movements during non-rapid eye movement sleep. J Clin Neurophysiol 3 314-323... 

Significant periods of movement are also evident during REM sleep periods, when REM sleep behavior disorder is present (117,138). These include vocalizations, increased muscle tone, and complex muscle movements. During NREM sleep, increased incidence of periodic limb movements is also evident in up to one third of Parkinson s patients (139). Muscle activity is often present in limbs that also express tremor during waking periods. 

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