Cognitive and behavioral aspects of PSP since Steele, Richardson and Olszewski's description of PSP 40 years ago and Albert's delineation of the subcortical dementia 30 years ago

Although researchers are now familiar with progressive supranuclear palsy ( PSP) and its characteristic subcortical dementia, this was not the case prior to seminal descriptions by Steele, Richardson, Olszewski and Albert. In fact, the first three authors identified this disorder, and the last one introduced the classification of the dementias according to the anatomical involvement. This paper is in honor of their contributions, and will also outline the changes that have occurred since their seminal works.