This study will evaluate flortaucipir for brain imaging of tau in subjects with progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and healthy volunteers.

Inclusion Criteria:

Cognitively Healthy Volunteers

• Mini-mental state examination (MMSE) ≥ 28
• No history of cognitive decline or parkinsonian motor disorder

CBD and PSP subjects

• Able to walk 10 steps with minimal assistance
• MMSE ≥ 14 and ≤ 30
• Subject has a reliable study partner who agrees to accompany subject to visits and spends at least 5 hours per week with the subject

PSP subjects only

• Meet National Institute of Neurological Disorders and Stroke - Society for Progressive Supranuclear Palsy (NINDS-SPSP) probable or possible PSP criteria as modified for the Neuroprotection and Natural History Parkinson Plus Syndromes (NNIPPS) clinical trial

CBD subjects only

• Meets 2013 consensus criteria for possible or probable corticobasal degeneration, corticobasal syndrome (CBS) subtype

Exclusion Criteria:

All subjects

• Have evidence of structural abnormalities such as vascular disease, large strokes or severe white matter disease or other mass lesion on screening MRI
• Claustrophobia
• Current clinically significant cardiovascular disease or clinically significant abnormalities on screening electrocardiogram (e.g. corrected QT interval >450 msec)
• Have a history of risk factors for Torsades de Pointes (e.g. heart failure, hypokalemia, family history of long QT syndrome)
• Have a current clinically significant infectious disease, endocrine or metabolic disease, pulmonary, renal or hepatic impairment, or cancer
• Females of childbearing potential who are not surgically sterile, not refraining from sexual activity or not using reliable methods of contraception
• Have received or participated in a trial with investigational medications in the past 30 days
• Have had a non-study related radiopharmaceutical imaging or treatment procedure within 7 days prior to the study imaging session
• Have a history of neuroleptic use for a prolonged period of time or within the past 6 months

PSP and CBD subjects

• Have evidence of amyloid deposition
• Meet National Institute on Aging-Alzheimer's Association criteria for probable Alzheimer's Disease
• Have any other neurological condition other than CBS or PSP that could account for cognitive or motor deficits
• Serum or plasma progranulin level less than one standard deviation below the normal subject mean for the laboratory performing the assay
• Have a high-risk family history suggestive of tar DNA binding protein (TDP)-43 pathology or known mutations