The phenotypic spectrum of progressive supranuclear palsy.

Traditionally, the clinical picture of progressive supranuclear palsy (PSP) was defined by early postural instability with falls, supranuclear vertical gaze palsy, symmetric akinesia and rigidity, frontal and subcortical dementia, and pseudobulbar palsy, leading to death after a mean disease duration of approximately six years. A definite diagnosis of PSP depends on neuropathological confirmation. In recent years, clinico-pathological studies have drawn attention to various "atypical" clinical manifestations of PSP. In these, a clinical diagnosis of PSP is delayed or never accomplished. Comprehensive understanding of the natural history of PSP is required to permit an early and accurate diagnosis. Based on current evidence, this review provides an update on the clinical spectrum of PSP.