Amantadine-induced myoclonus in a patient with progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) is a tauopathy that generally results in a hypokinetic disorder. Treatment is largely symptomatic, with some small studies indicating a benefit with dopaminergic therapy. Myoclonus is a hyperkinetic disorder that can be seen as part of later stage Parkinson's disease and in multiple system atrophy, but is rarely seen in PSP. Here we report a case of myoclonus precipitated by amantadine in a patient with PSP.