Mandatory features - all of the following:
(1) progressive clinical course
(2) vertical supranuclear palsy with abnormalities in downward gaze
(3) severe postural instability AND unexplained falls
Diagnosis requires the absence of all of the following (which are intended to exclude other parkinsonian disorders):
(1) focal neurological findings
(2) focal lesion on imaging studies
(3) early cortical dementia (amnesia with either aphasia, apraxia or agnosia)
(4) alien hand syndrome
(5) unilateral dystonia
(6) non-iatrogenic dysautonomia
(7) early or prominent cerebellar signs
(8) hallucinations
(9) history of encephalitis
PSP may be confused with other disorders such as diffuse Lewy body dementia, multiple system atrophy, and corticobasal ganglionic degeneration.
Performance:
• The sensitivity is low (57%).
• The positive predictive value is 85%.
