Restless leg syndrome (RLS) is a disorder that causes unpleasant or tingling sensations in the legs, and less commonly, in the arms.  This symptom tends to occur in the evenings and at night.  It also worsens at rest and is usually relieved by movement.  It is not related to emotional or psychological disorders. RLS can lead to trouble falling asleep, waking at night, daytime hyperactivity or sleepiness.   

Periodic limb movement disorder (PLMD) is a sleep disorder resulting from frequent limb movements during sleep.  A sleep study can help diagnose this disorder.  Because occasional leg movements can occur in sleep, there are certain kinds of leg movements that are typical of PLMD.  Children with PLMD are usually not aware of these movements, although parents may observe frequent leg movements during sleep.  Most children with restless leg syndrome have PLMD.  However children with PLMD may not have restless leg syndrome.

How Common Are These Conditions? 

One study suggests that almost half of adults with restless leg syndrome have their first symptoms during childhood. Children with ADHD or children with iron deficiency anemia are at risk for restless leg syndrome and PLMD.