Progressive supranuclear palsy is a late-onset degenerative disease of the central nervous system characterized by balance difficulties, vertical gaze palsy, dysarthria, dysphagia, and axial dystonia. Pathologic findings include neurofibrillary degeneration of extrapyramidal neurons. It remains an intractable and underrecognized neurodegenerative illness with a median survival of only 7 years. However, patients will benefit from accurate, early diagnosis that allows them to understand the prognosis, to avoid unnecessary tests and useless treatments, and to avail themselves of disease-specific support services. Advances in understanding the tau protein aggregation and mitochondrial dysfunction of progressive supranuclear palsy and the toxic and genetic insults underlying them are accruing swiftly. In this article, the author describes the subtypes of progressive supranuclear palsy as well as advances in pathology, imaging, and genetics of the disorder.
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• Ophthalmoparesis, especially downgaze impairment, is a classic clinical feature of progressive supranuclear palsy that may appear later in the course of the disorder.
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• Slowing of downward saccades appears earlier in the clinical course of progressive supranuclear palsy.
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• Multiple subtypes of progressive supranuclear palsy have been identified, including the classic Richardson syndrome, progressive supranuclear palsy-parkinsonism (PSP-P), or pure-akinesia-with-gait-freezing (PAGF).
Historical note and terminology
The first complete clinicopathologic description of progressive supranuclear palsy was published in 1964 (139). However, there were 13 earlier clinical cases in the literature, 6 with autopsy (18). Some of these antedate the 1920s epidemic of postencephalitic parkinsonism, suggesting that progressive supranuclear palsy is not a variant of that condition despite their pathological similarity (19). The meticulously described motor disorder of a character in an 1857 Dickens novel is a convincing picture of progressive supranuclear palsy (81). Since the early 1960s when many astute movement disorder specialists were unable to recall having seen progressive supranuclear palsy, this disorder has become commonly recognized at movement disorder referral centers, comprising 4% to 5% of their cases of parkinsonism (42).
Monographs (86; 18) and a layperson's guide (40) are available. Lay organizations were founded in the United States in 1990 (The Society for Progressive Supranuclear Palsy) and in Europe in 1994 (The Progressive Supranuclear Palsy (PSP-Europe) Association).