Clinical features and criteria for the diagnosis of progressive supranuclear palsy

The neurofibrillary tau pathology of progressive supranuclear palsy (PSP) has been associated with a number of different clinical syndromes that all ultimately lead to death and disability within 6-10 years. In 1964, Steele, Richardson and Olszewski predicted that the classic clinical syndrome they had described was specific to the topographic distribution of PSP-tau neurodegeneration and that other clinical syndromes may occur if other brain regions were affected. The spectrum of clinical disease related to PSP-tau pathology is indeed broader than 40 years ago. In addition to the classic form of PSP (Richardson's syndrome), a number of clinical variants caused by the same neurodegenerative process have been identified. These include PSP-Parkinsonism, PSP-corticobasal syndrome, PSP-pure akinesia with gait freezing and PSP-progressive nonfluent aphasia. Here we review the clinical pictures of these syndromes and propose practical diagnostic guidelines to aid the clinician in tackling the challenges presented by the multifaceted condition of PSP-tau pathology.