Cognitive deficits in the Steele-Richardson-Olszewski syndrome (progressive supranuclear palsy).

Clinical examination of 33 consecutive newly diagnosed cases of Steele-Richardson-Olszewski syndrome revealed evidence of cognitive impairment in 20. Eighteen of the 27 right handed patients who underwent neuropsychological assessment had intellectual impairment (mild in nine and marked in nine patients). The pattern of abnormalities was similar to but more severe than those previously reported in Parkinson's disease, with particular difficulties in carrying out tests which are believed to be sensitive to frontal lobe dysfunction.