Natural history and clinical features of progressive supranuclear palsy: a clinical study.

Progressive supranuclear palsy (PSP or Steele-Richardson-Olszewski syndrome) is one of the most-common types of atypical parkinsonism. To characterize the natural history and the clinical features of PSP, we reviewed the records of 25 patients followed in our clinic since 1991, with a clinical diagnosis of PSP according to NINDS and Golbe criteria. Progressive onset of early bilateral bradykinesia and postural instability with falls during the 5th decade strongly support the diagnosis of PSP in our patients. Pseudobulbar symptoms are very common at onset and during the course of the illness.