Sleep and Its Disorders in Children

Timothy F. Hoban, MD


Semin Neurol. 2004;24(3) 

In This Article

Sleep-Related Movement Disorders in Children

Rhythmic movement disorder (RMD) is characterized by recurrent, well-stereotyped episodes of rhythmic motor activity that are associated with sleep, usually occurring during drowsiness or light NREM sleep but sometimes during wakefulness as well.[61] The movements may involve the head, trunk, and limbs either alone or in combination at a typical frequency of 0.5 to 2 Hz (Fig. 1). Several distinct variations have been described, including head banging (jactatio capitis nocturna) and body rocking, in which affected children rise upon the hands and knees while vigorously rocking the entire body in an anteroposterior direction.

Figure 1.

Thirty-second polysomnogram epoch documenting rhythmic movement disorder in a 4-year-old girl. Rhythmic activity is clearly evident on all electroencephalogram (EEG) and electromyogram (EMG) leads during a period of head banging recorded during wakefulness, as indicated by black arrows. Activity on the snore channel reflects the synchronous vocalizations commonly seen in this condition rather than snoring. Channels are as follows: electrooculogram (left, right), chin EMG, EEG (left central, right central, left occipital, right occipital), electrocardiogram (two leads), limb EMG (left arm, right arm, left leg, right leg), snoring, airflow (oral, nasal-oral), respiratory effort (thoracic, abdominal), nasal pressure, oxygen saturation.

Although rhythmic motor activity during drowsiness and light sleep is observed in a majority of infants, this usually subsides spontaneously by 5 years of age. Rhythmic movements persisted for 6% of 5-year-olds in one series and body rocking persisted in 3% of 13-year-olds in another series.[52,62] Rhythmic movement disorder most commonly affects otherwise healthy children but may also be seen in association with autism and other developmental disabilities. For most affected children, RMD is a self-limited condition that does not require treatment. For youngsters exhibiting particularly violent movements, use of protective padding in the crib or bed is often helpful. Successful treatment using clonazepam, citalopram, and behavioral modification techniques has also been reported.[61]

Restless legs syndrome (RLS) and periodic limb movement disorder (PLMD) have only recently been identified as affecting children. The precise prevalence of RLS in children remains uncertain, but several studies suggest that symptoms of RLS may be common in children. One survey of 138 adults with RLS identified onset of symptoms by age 20 in 43% and by age 10 in 18%, suggesting that childhood onset may be more common than generally recognized.[63] In a survey completed by parents of 866 children attending general pediatrics clinics, restlessness of the legs in bed was reported for 17% of children aged 2.0 to 13.9 years.[64] The clinical features, known comorbidities, and available treatment for RLS and PLMD in children are comparable to those for adults. These are reviewed by Lesage and Hening elsewhere in this issue. One pediatric aspect of RLS /PLMD that deserves brief elaboration is emerging evidence of an association between PLMD and neurobehavioral problems in children.[65] Some studies have suggested that attention-deficit/hyperactivity disorder (ADHD) is overrepresented in children with PLMD, including one retrospective assessment of 129 children with moderate to severe PLMD where 117 (90%) of subjects carried a comorbid diagnosis of ADHD.[66] Conversely, there is more limited evidence that PLMD may be more common among children with ADHD. In one study of 14 consecutive children with newly diagnosed ADHD (DSM-IV criteria), nine patients (64%) exhibited over five PLMs per hour of sleep on PSG, as opposed to no patients among the age- and sex-matched controls (P < 0.0015).[67] Further research is required to more fully define the potential relationship between RLS/PLMD and daytime neurobehavioral symptoms.


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