The SP@ study ( ClinicalTrials.gov , NCT@ ) 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 @ ( CGI-@ ) , RLS @-item questionnaire ( RLS-@ ) , and the RLS-quality of life questionnaire ( RLS-QoL ) in patients with moderate to severe idiopathic RLS .