Rhythmic Movement Disorder

Rhythmic movement disorder, characterized by stereotyped repetitive movements of the head and neck, or sometimes the trunk, is also called head-banging, head-rolling, body-rocking, or body-rolling depending on the type of movement. Other terms sometimes employed include jactatio capitis nocturna and rhythmie du sommeil. The movements occur during drowsy wakefulness and stage 1 sleep at a rate of 0.5-2 Hz, rarely during deeper stages of NREM or REM sleep, and may last from a few seconds to as long as half an hour. When head-banging is the principal symptom, patients may repeatedly and forcefully bang their heads into the pillow, headboard, or wall while lying in a prone position. Rolling head or body movements and leg or arm banging may occur instead of or in addition to head-banging. They occur in the majority of infants, but have usually resolved by age 4 (Klackenberg, 1987). In occasional patients, symptoms persist into adolescence or adulthood.

Although the movements may be a source of concern for parents, daytime symptoms are generally absent, although patients occasionally bang their heads hard enough to produce such injuries as bruised foreheads or, rarely, retinal injury or subdural hematoma. For older children and adults, the movements may be embarrassing.

Among infants who have sleep recordings for other reasons, rhythmic movement disorder is a common incidental finding. Other causes in infants of rhythmic muscle activity during polysomnography include bruxism and sucking on a pacifier. The cause of the rhythmic movements is uncertain; a soothing effect related to vestibular stimulation may contribute. Episodes are more common in infants and children with static encephalopathy.

In most patients, the disorder can be diagnosed based on the history. Seizures may be a consideration, particularly in patients with mental retardation and epilepsy. In rare cases, epileptic seizures may be associated with rocking movements. If epilepsy is suspected, VPSG may be useful. Episodes of rhythmic movements are not associated with EEG abnormalities and show little change in the frequency of movements over the course of an episode. Unlike seizures that typically show an initial increase in the amplitude and frequency of movements followed by a slowing in frequency in the second half of the episode, the frequency of movements remains essentially constant during an episode, although the amplitude may decline at the end of an episode.

Most children do not require treatment and parents should be reassured that the disorder usually resolves. Padding the headboard and crib may reduce bruising or other injuries. For patients with severe head-banging, treatment is difficult although behavior therapy or a benzodiazepine is occasionally useful.

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