J. Clifford Richardson and 50 years of progressive supranuclear palsy.

OBJECTIVE: To trace the historical events leading to Richardson's clinical description of progressive supranuclear palsy (PSP) in the context of subsequent observations of its clinical heterogeneity and pathologic overlap with other tauopathies.
BACKGROUND: Fifty years ago, Canadian neurologist J. Clifford Richardson identified patients in Toronto with a syndrome of supranuclear vertical gaze palsy, pseudobulbar palsy, axial rigidity-in-extension, and cognitive impairment. In his seminal description, Richardson predicted that further clinicopathologic observations would broaden the clinical syndrome and that this was unlikely to be a disorder restricted to the Toronto region.
METHODS: The recollections of two of Richardson's contemporaries and archival material from his time were used as primary materials. Publications that follow the evolution of his observations were examined.
RESULTS: Recent factor analysis of pathologically verified PSP cases has confirmed the accuracy and uniformity of the original classic clinical description of PSP and vindicated Richardson's prediction of clinical variants. Most notably, a presentation with Parkinson syndrome and absent gaze palsy has been identified, with less severe PSP-tau pathology.
CONCLUSIONS: In recognition of his seminal observations, we propose that the classic clinical presentation of PSP-tau pathology be renamed Richardson's disease, and that the commonest clinical variant be termed PSP-parkinsonism.