To compare the efficacy, safety and tolerability of Coenzyme Q 10 versus placebo in patients with atypical parkinsonian syndromes corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) ).

Inclusion Criteria:

• Patients fulfilling the diagnostic criteria of PSP and CBD (above) and who were diagnosed within the past 5 years
• Age > 40
• Subjects receiving anticholinergics, amantadine, dopamine agonists, carbidopa/levodopa, eldepryl, or comtan must be on a stable dose for at least 30 days prior to baseline visit.
• Patients agreeable to participate in the study.

Exclusion Criteria:

• Prior or concurrent therapy with anticholinergics, amantadine,a dopamine agonist,carbidopa/levodopa or comtan within 30 days of the baseline visit.
• Parkinsons disease or any other atypical parkinsonism; Parkinsonism due to drugs.
• History of pallidotomy, thalamotomy, deep brain stimulation or fetal tissue transplant.
• Previous use of coenzyme Q10 within 60 days of the baseline visit.