Prediagnostic Phase of Progressive Supranuclear Palsy in a Longitudinal Epidemiological Study of Dementia and Aging.

A 63-year-old previously healthy man participated in a longitudinal epidemiologic study of dementia and aging. Although he initially showed no subjective symptoms and a normal motor function, verbal fluency test scores gradually declined, and progressive atrophy of the frontal lobes was observed on magnetic resonance imaging of the head. At 71 years old, progressive supranuclear palsy (PSP) was diagnosed after supranuclear gaze palsy, and gait disturbance developed. This longitudinal epidemiological study suggests that verbal symptoms and mild frontal lobe atrophy may be evident in the premotor phase of PSP.