Ataxias and hyperkinetic movement disorders

Ataxias arise from dysfunction of the cerebellum or its connections, causing irregular disordered movement. There are several different hyperkinetic movement disorders, distinguished by clinical assessment: in chorea, the involuntary movements are random; in dystonia, the movements are patterned; in tremor, the movements are rhythmic; in myoclonus, the movements are very brief, jerky and irregular; and in tics, the movements are suppressible and associated with an underlying urge sensation. This article gives an approach to diagnosing patients with ataxic and hyperkinetic movement disorders and discusses some common and important diagnostic associations.