Pelvic movements as rhythmic motor manifestation associated with restless legs syndrome.

Video-polysomnographic monitoring of a patient with a 4-year history of an unpleasant restless sensation originating in his lower abdomen showed stereotyped, repetitive, rhythmic pelvic body movements resembling coital behaviour at the wake-sleep transition. We discuss the association between restless legs syndrome and rhythmic movement disorder as a particular manifestation of a spectrum of rhythmic sleep-related movement disorders.