Variable periodicity of periodic limb movements of sleep in children

Recordings of leg activity in a 10-year-old male with periodic limb movement disorder (PLMD) and a strong family history of restless legs syndrome (RLS). Each polysomnographic segment is 3.5 minutes long.
Top panel: An example of high-periodicity leg movement activity, with consecutive intervals in the approximate range of 20 to 40 seconds.
Bottom panel: An example of low-periodicity leg movement activity in the same child.