Progressive supranuclear palsy

**Definition:** Progressive supranuclear palsy (PSP) is a late-onset neurodegenerative disease characterised by supranuclear gaze palsy, postural instability, progressive rigidity, and mild dementia. Five clinical variants have been described with clinicopathological correlations: Classical PSP (Richardson's syndrome), and four atypical variants of PSP including PSP-Parkinsonism (PSP-P), PSP-Pure akinesia with gait freezing (PSP-PAGF), PSP-corticobasal syndrome (PSP-CBS), and PSP-progressive non fluent aphasia (PSP-PNFA).