Characterizing behavioral and cognitive dysexecutive changes in progressive supranuclear palsy

Frontal lobe dysfunction is a prominent feature of many neurological disorders. Early diagnosis may be enhanced by establishing a profile of cognitive, behavioral, and emotional change. Traditional psychometric assessment focuses on cognitive dysfunction and fails to identify behavioral changes, particularly those associated with orbitofrontal dysfunction. We examined progressive supranuclear palsy (PSP), a prototypical subcortical dementia with frontal features, using commonly available neuropsychological measures and a modification of the Katz Adjustment Scale-Relatives (KAS-R), an instrument first developed to assess dysexecutive changes in head-injured patients. Executive tests identified deficits in reasoning, planning, set shifting, verbal fluency, information processing speed, and response initiation. On the KAS-R, changes in apathy, social withdrawal, and independence were observed, with little change in belligerence, social irresponsibility, uncooperativeness, obstreperousness, anxiety, and depression. The results show the potential utility of this instrument in characterizing behavioral and emotional changes associated with frontal lobe dysfunction in neurodegenerative disease.