Tags: Disease.
Rhythmic Movement Disorder (or RMD) is a neurological disorder characterized by involuntary repetitive movements of large muscles groups immediately before and during sleep often involving the head and neck. It was independently described first in 1905 by Zappert as jactatio capitis nocturna and by Cruchet as rhythmie du sommeil. The majority of RMD episodes occur during NREM sleep although REM movements have been reported.