National Sleep Foundation

Chapter 7: Sleep-Related Movement Disorders

Sleep-Related Rhythmic Movement Disorder (RMD)

Sleep-Related Rhythmic Movement Disorder (RMD) involves large and stereotyped rhythmic movements, such as head banging, head rolling, rocking on the elbows and knees, rocking and/or rolling the body from side to side.83 (RMD differs from Sleep-Related Rhythmic Movements in that the latter typically do not result in sleep disruption or sleep-related injury.)

These movements involve large muscle groups and occur near sleep onset or during sleep. The condition can occur during wakefulness, however, particularly among those with intellectual developmental disorders.

Many cases of childhood rhythmic movements or Rhythmic Movement Disorder remit after a few years, and do not return again.

References 

83 Thorpy M, “Classification of Sleep Disorders,” in Kryger M, Roth T, Dement W (ed.), Principles and Practice of Sleep Medicine (5th Edition), St. Louis: Elsevier Saunders, 2011, pages 680 - 693.