Progressive supranuclear palsy

Progressive supranuclear palsy (PSP) is a late-onset neurodegenerative disease involving the gradual deterioration and death of specific volumes of the brain, linked to 4-repeat tau pathology.^[1][2][3] The condition leads to symptoms including loss of balance, slowing of movement, difficulty moving the eyes, and cognitive impairment.^[1] PSP may be mistaken for other types of neurodegeneration such as Parkinson's disease, frontotemporal dementia and Alzheimer's disease. It is the second most common tauopathy behind 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.^[1]

PSP was first officially described by Richardson, Steele, and Olszewski in 1963 as a form of progressive parkinsonism.^[4] However, the earliest known case presenting clinical features consistent with PSP, along with pathological confirmation, was reported in France in 1951.^[5] Originally thought to be a more general type of atypical parkinsonism, PSP is now linked to distinct clinical phenotypes including PSP-Richardson's syndrome (PSP-RS), which is the most common sub-type of the disease.^[6] As PSP advances to a fully symptomatic stage, many PSP subtypes eventually exhibit the clinical characteristics of PSP-RS.^[3]

PSP, encompassing all its phenotypes, has a prevalence of 18 per 100,000, whereas PSP-RS affects approximately 5 to 7 per 100,000 individuals.^[1][3] The first symptoms typically occur at 60–70 years of age. Males are slightly more likely to be affected than females.^[1] No association has been found between PSP and any particular race, location, or occupation.^[1]