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Although large-scale epidemiologic studies are lacking, pediatric movement disorders are relatively common. Many movements that are brought to clinical attention are transient and may be associated with normal development. Additionally, the natural history of specific disorders varies and must be interpreted in the context of a child's developmental stage. A careful history, physical examination, and direct observation of the movements in question are critical for diagnosis and management of pediatric movement disorders (Table 13-1). Factors that should prompt consideration of more significant underlying neurological disorder include the progression of symptoms, a family history of a heritable neurological disease, complications during childbirth, a failure of the child to reach developmental milestones, and significant functional impairment. Serological tests, electroencephalography, and imaging studies may contribute in unusual cases, but in the majority of cases it is the clinical impression of the treating physician that drives both diagnosis and treatment of pediatric movement disorders.
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Movement disorders can be broadly classified based upon whether they are hyperkinetic or hypokinetic. Hyperkinetic disorders involve excessive involuntary movements, including tics, chorea, myoclonus, dystonia, and tremor. Hypokinetic disorders manifest with bradykinesia (paucity or slowness of movement) and rigidity (abnormal muscle stiffness), as can be seen in parkinsonism. In contrast to adults, the overwhelming majority of movement disorders in children are hyperkinetic. In a tertiary pediatric neurology movement disorders practice, Fernandez-Alvarez and Aicardi reported tics (39%), dystonia (24%), tremor (19%), chorea (5%), myoclonus (3%), akinetic-rigid syndromes (2%), and mixed disorders (8%) out of a sample of 684 children.1 This chapter will focus on the most common types of movement disorders encountered in pediatric neurology practice, emphasizing correct identification and appropriate initial management.
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Tics are sudden, rapid, nonrhythmic repetitive movements or vocalizations, usually in the presence of an otherwise normal neurological exam. Most experts regard tic disorders along a spectrum of disease from transient tic disorders, characterized by the presence of simple tics that spontaneously resolve, to Tourette syndrome (TS), a chronic disorder featuring both motor and vocal tics. Since the overall incidence of tics may be as high as 20% in the school-age population,2 the development and resolution of a simple tic in a child could almost be considered a part of normal development. Tic disorders are five times more common in boys than in girls, and the median age of onset ...