Progressive supranuclear palsy (PSP) is a late-onset neurodegenerative disease involving the gradual deterioration and death of specific volumes of the brain. The condition leads to symptoms including loss of balance, slowing of movement, difficulty moving the eyes, and cognitive impairment. PSP may be mistaken for other types of neurodegeneration such as Parkinson's disease, frontotemporal dementia and Alzheimer's disease. The cause of the condition is uncertain, but involves the accumulation of tau protein within the brain. Medications such as levodopa and amantadine may be useful in some cases. PSP affects about six people per 100,000. The first symptoms typically occur at 60¨C70 years of age. Males are slightly more likely to be affected than females. No association has been found between PSP and any particular race, location, or occupation.

Reference
Wiki: Progressive superanuclear palsy