Clinical features differentiating patients with postmortem confirmed progressive supranuclear palsy and corticobasal degeneration

Progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) ar e often clinically confused with each other because they share a rapid dise ase progression parkinsonism that responds poorly or transiently to levodop a therapy, and associated signs (e.g., ocular abnormalities, pyramidal sign s and cognitive involvement). To improve the accuracy in diagnosing these d isorders, this study examined the clinical features of 51 patients patholog ically diagnosed with PSP and CBD. Logistic regression analysis identified two sets of predictors (models) for CBD patients, one consisting of asymmet ric parkinsonism, cognitive disturbances at onset and instability and falls at first clinic visit, and the other one of asymmetric parkinsonism, cogni tive disturbances at symptom onset and speech disturbances. While PSP patie nts often had severe postural instability at onset, symmetric parkinsonism, vertical supranuclear gaze palsy, speech and frontal lobe-type features, C BD patients presented with lateralized motor (e.g., parkinsonism, dystonia or myoclonus) and cognitive signs (e.g., ideomotor apraxia, aphasia or alie n limb). On the other hand, CBD patients presenting with an alternate pheno type characterized by early severe frontal dementia and bilateral parkinson ism were generally misdiagnosed. PSP patients without vertical supranuclear gaze palsy were misdiagnosed. Recognizing the features which differentiate these disorders and the less obvious disease presentations as well as deve loping an increased index of suspicion will improve the diagnostic accuracy of these disorders.