- Subject meets the diagnosis of idiopathic Restless Legs Syndrome (RLS) based on the 4 essential clinical features according to the International Restless Legs Syndrome Study Group (Allen et al,2003): 1. An urge to move legs, usually accompanied or caused by uncomfortable and unpleasant sensations in the legs (The urge to move can be present without uncomfortable sensations. Arms or other body parts can also be affected) 2. The urge to move or unpleasant sensations begin or worsen during periods of rest or inactivity, such as lying or sitting 3. The urge to move or unpleasant sensations are partially or totally relieved by movement, such as walking or stretching, at least as long as the activity continues 4. The urge to move or unpleasant sensations are worse in the evening or night than during the day or only occur in the evening or night (When symptoms are very severe, the worsening at night may not be noticeable but must have been previously present)