The SP790 study ( ClinicalTrials.gov , NCT00136045 ) showed benefits of rotigotine over placebo in improving symptom severity of restless legs syndrome ( RLS ) , also known as Willis-Ekbom disease , on the International Restless Legs Syndrome Study Group rating scale ( IRLS ) , Clinical Global Impression item 1 ( CGI-1 ) , RLS 6-item questionnaire ( RLS-6 ) , and the RLS-quality of life questionnaire ( RLS-QoL ) in patients with moderate to severe idiopathic RLS .