The clinical syndrome of PSP responds poorly to all available forms of therapy used in Parkinson's Disease (PD). Currently, no effective treatment exists. Coenzyme Q10 in high doses has been shown to be a beneficial therapy in PD and might possibly be a beneficial therapy for PSP. This study will compare the efficacy, safety and tolerability of Coenzyme Q10 versus placebo in patients with atypical parkinsonian syndrome, progressive supranuclear palsy (PSP).