CASE PRESENTATION A 76-year-old woman was seen for chorea and imbalance. On the background of good health, these problems were first noticed 6 years previously and had been slowly worsening. The patient had not noticed any significant cognitive symptoms nor had her family, but they did observe that she had more difficulty processing several mental tasks simultaneously. She had had several falls and was using a walker. She was not depressed. There was no history of drugs known to cause movement disorders, but one of the two neurologists she saw previously had started thioridazine for the chorea; in neither case was a diagnosis established. Magnetic resonance imaging (MRI) of the brain was interpreted as normal.