Rhythmic Movement Disorder

Rhythmic movement disorder (RMD) is defined as a group of stereotyped, repetitive movements most often involving large muscles that typically begins prior to sleep onset and may be sustained into transitional sleep. The most frequent forms of RMD are head banging (often referred to as jactatio capitis nocturna), body rocking, and body rolling, while leg rolling and leg banging are less common (Table 42.1).² These movements can range in intensity from subtle to violent, and treatment is not usually required unless daytime consequences related to sleep quality are present, sleep-related injury occurs, or there are significant life-threatening issues for other family members.¹ The duration of these movements can last from several minutes to several hours. The movement frequency can vary, but the rate is usually between 0.5 and 2 per second, with duration of the individual cluster of movements generally less than 15 minutes.¹ In contrast to sleep-related epilepsy, children with RMD usually can voluntarily stop the movements upon request. Movements can be manifest at sleep onset, after nocturnal arousals, or in combination. Patients in whom frequent episodes of RMD are noted during the night should be clinically evaluated for causes of sleep fragmentation such as obstructive sleep apnea or periodic limb movements of sleep. In patients with head banging, physical examination can demonstrate bruising, callus formation, or discrete patches of hair loss at the point of contact with the object they are striking with their head. Patients with leg rolling or body rolling may demonstrate bruising at sites of impact with furniture or the wall. Polysomnography is rarely needed to make the diagnosis, but will generally demonstrate rhythmic movements during wakefulness and extending into transitional sleep.³

Rhythmic head banging, body rocking, and head rolling are very common in childhood, with up to 60% of infants displaying the characteristic signs and symptoms by 9 months of age. RMD prevalence decreases with age, and is only seen in 5% of 5-year-olds. This disorder is more common in males, with a 4 : 1 male to female ratio.¹ Though less common, RMD can continue into adolescence or adulthood.^4–6 Although initially thought to be suggestive of autism and mental retardation, RMD is common in neurodevelopmentally normal patients, even when it persists into adulthood.⁵ An association between attention deficit hyperactivity disorder (ADHD) and RMD has been demonstrated in one small study,⁷ but more research is required.

Various management and treatment strategies have been suggested. The key aspect of rhythmic movement disorder management is helping prevent injury to the child and providing parental education about the nature of this condition. In a typical child with RMD who has no apparent daytime behavioral or social issues, parents should be reassured that the condition is common and almost always self-limiting. Parents should be instructed to place the child in an environment where injury from these repetitive and sometimes violent movements can be avoided. Cribs and beds should be in good repair and inspected regularly. If falling off the bed is a concern, safe bedrails might be considered. Parents can also move the bed away from the wall or have the child sleep on a mattress on the floor to ensure his or her safety.

Interventions to control the movements generally seek to provide the child with alternative means of self-soothing. The establishment of a bedtime routine made up of consistent and progressively less stimulating activities focused on helping the child decelerate can be a sufficient intervention to help the child fall asleep without needing to engage in rhythmic movements. Fixing a wake-up time and manipulating naps can also be effective in helping the child fall asleep without relying on repetitive motions to relax. A more comprehensive review of these behavioral approaches is included in Chapter 9, Promoting Healthy Sleep Practices for Children and Adolescents.

Other behavioral and psychological approaches have given attention to replacing the rhythmic movements with alternate means of soothing. The use of a metronome as a stimulus substitution demonstrated some success in one study,⁴ as has holding the child while patting or rocking the child at the same rate as their rhythmic movements. Etzioni and colleagues used a 3-week controlled sleep restriction regimen, and found that the combination of mild sleep deprivation along with usage of hypnotics at treatment initiation abolished rhythmic movements and treat the disorder.⁸ This study suggests that RMD may represent a learned behavior that the child uses to help transition from wakefulness to sleep. In severe cases, or in cases in which the patient’s rhythmic movements are a threat to the child’s safety, pharmacologic treatment can be considered. A small dose of clonazepam has been shown to be effective in up to 50% of cases.⁴ Antidepressants have also been tried with limited success.