Hemiballism in a patient with parietal lobe infarction.

A 60-year-old man with a history of atrial fibrillation had an acute onset of ballistic movements of the left limbs with sensory extinction (video on the Neurology® Web site at www.neurology.org). The patient was treated with risperidone and anticoagulant; symptoms subsided 3 days later. Brain MRI showed acute infarction of the right posterior parietal lobe (figure 1) and SPECT revealed hypoperfusion in the right frontoparietal areas (figure 2).