Q: Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.
Context: The article briefly summarizes the milestones leading to current knowledge and the possibility of treating one of the most widespread and perhaps least known diseases, restless legs syndrome (RLS). Until the mid-twentieth century, the syndrome first described by Willis (1685), was sporadically reported in medical literature and in most cases deemed a bizzare condition. It was only with Ekbom's detailed clinical description of the syndrome (1944) and the polygraphic recordings of Coccagna et al. (1962) that RLS became well-recognised clinical entity. Since then, almost all sleep laboratories have devoted much of their research to discovering the pathogenetic mechanisms underlying the disease and devise increasingly specific treatment. Major advances have been made in recent years, but a full understanding of RLS is still a long way off.
Question: Willis-Ekbom disease is also known as?
A:
restless legs syndrome