accuracy of clinical diagnosis of progressive supranuclear palsy we assessed the accuracy of clinical diagnosis of progressive supranuclear palsy psp steelerichardsonolszewski disease and the validity of existing sets of clinical diagnostic criteria for psp see appendix using neuropathologically examined cases from the queen square brain bank for neurological disorders diagnosis of psp was made by 40 different physicians and 60 cases clinically diagnosed as psp when last assessed in life were studied in 47 cases 78 the diagnosis of psp was confirmed pathologically falsepositive diagnoses included parkinsons disease with significant additional cortical lewy body n 3 or alzheimer n 1 pathology multiple system atrophy n 4 and corticobasal degeneration picks disease motor neurone disease cerebrovascular disease and a sporadic case of frontotemporal dementia and parkinsonism linked to chromosome 17 1 case each most cases of psp were diagnosed accurately by neurologists at the final assessment although application of national institute of neurological disorders and the society for psp possible category marginally improved the accuracy of initial clinical diagnosis none of the existing operational criteria could significantly improve accuracy of the final clinical diagnosis