RLS, a common, but often misdiagnosed or underdiagnosed, sleep movement disorder which is characterised by a distressing urge to move the legs and sometimes also other body parts, usually accompanied by a marked sense of discomfort or pain in the legs. RLS is typically triggered by rest or inactivity and its symptoms are temporarily relieved or suppressed by movement.  The urge to move the legs is accompanied by unpleasant sensations in the lower extremities.  These unpleasant sensations can be burning, creeping, tugging or tingling inside the legs, ranging from being uncomfortable to painful.  The symptoms begin to worsen during periods of inactivity, particularly at night, and interfere with sleep. The particular mechanism triggering RLS is not currently known. Recent research suggests that it affects about 10% of adults in North America and Europe (National Sleep Foundation, US, 2003).