Causes of Chorea among Older Adults

Introduction Movement disorders can be subdivided into two types: hypokinetic, such as parkinsonism, and hyperkinetic, characterized by an excessive amount of motor activity. The hyperkinetic disorders are further characterized as rhythmic or nonrhythmic. The prototypic rhythmic hyperkinetic movement disorder is tremor, while irregular (or nonrhythmic) hyperkinetic movement disorders include chorea, ballismus, athetosis, dystonia, tics, and myoclonus. Of the arrhythmic hyperkinetic movement disorders, chorea is one of the most common. The term chorea comes from the Greek word khoreia, which means “dancing.” It is characterized by continuous, unsustained, rapid, and random contractions. Chorea may affect the distal limbs, face, and trunk. When the movements are slow and more sinuous, the term athetosis is used. Very proximal flinging movements are referred to as ballismus. The History of Chorea The root of chorea can be traced to the Middle Ages, when, coincident with the Black Plague, “dancing mania,” as chorea was then known, erupted in central Europe. Victims formed circles and persisted to dance together in wild delirium for hours on end.1 During a second plague outbreak in 1414, St. Guy or St. Vitus and, in later epochs, St. Willibrord, were called upon to intercede.2 The mystic and reformer Paracelsus introduced the concept of chorea as a naturally occurring medical condition, chorea naturalis, in contradistinction to consciously or unconsciously based emotional origins.3 Sydenham followed with more medical details,4 but the relationship between streptococcal endocarditis and resultant chorea were appreciated in the 19th century, largely due to Charcot5 and his French colleagues. In 1872, George Huntington published a report of adultonset hereditary chorea,6 and, in 1896, the pathological changes of caudate atrophy and neuronal degeneration in Huntington’s disease were elegantly documented by Anton.1 The pathophysiology of chorea is illustrated in Figure 1.