Kaat LD, Boon AJW, Kamphorst W etal.,Frontal presentation in PSP. Neurology 2007; 69:723-729
Diagnostic accuracy is poor (70 % initial misdiagnosis, 20 % terminal misdiagnosis). International criteria include falls in first year and vertical supranuclear palsy. PSP parkinsonism is a phenotype with assymmetric onset, tremor, levodopa response and longer disease duration. (see Williams DR et al. Brain 2005). A different phenotype of PSP is behavioral changes with impaired executive functions that may overlap FTD.
Clinical signs that were significant were abnormal score on the Thurstone (word fluency) with results often less than 3 or 5; applause sign in 72 % (http://neurologyminutiae.blogspot.com/search?q=applause+sign), and 85 % were abnormal when detailed cognitive evaluation was performed. These included especially abnormal executive functions, mental slowing, memory disturbance and change in personality.
Unreliable: dyskinesia, cortical sensory loss, dystonia and and cerebellar signs (all
< 3 %). The most common misdiagnosis was FTD. Urge incontinence was both significantly higher (2x) than PD and with increased mortality, as was older age. Phenotype did not affect survival. Both had median survival around 8 years. Article suggests importance of Thurstone and personality changes (applause sign) increase the sensitivity of diagnosis.