Association of idiopathic rapid eye movement sleep behavior disorder in an adult with persistent, childhood onset rhythmic movement disorder.

We present a case of a 41-year-old man with the association of REM sleep behavior disorder (RBD) and rhythmic movement disorder (RMD). The RMD had a childhood onset and persisted into adulthood. The RMD worsened with the development of RBD and has persisted despite successful treatment of RBD. However, the pathogenesis of RMD remains unclear and the movements have been suggested to play a maturational role as part of psychomotor development by stimulating the vestibular apparatus. Current models underlying the control of REM sleep may need to be refined to explain the observed association of RBD and RMD.