Utility of Frontal Assessment Battery in detection of neuropsychological dysfunction in Richardson variant of progressive supranuclear palsy.

Progressive supranuclear palsy is characterized by motor, cognitive and behavioral features. In Richardson's syndrome of PSP (PSP-RS) executive dysfunction is quite prominent. Frontal Assessment Battery (FAB) is one of the most popular screening tests in the differential diagnosis of bradykinetic rigid syndromes. The study aimed at analyzing FAB subscores in relation to neuropsychological assessment results. Twenty patients with PSP-RS (12 with probable and eight with possible diagnosis) participated in the study. Sixteen PSP-RS patients scored below 15 on FAB. Among four patients having scored above cut-off (12 points) on FAB, two demonstrated both executive and language deficits, while the other two presented with only selective executive deficits on comprehensive neuropsychological evaluation. FAB is a useful screening measure in PSP, but it may not detect subtle executive deficits. Moreover, language performance seems to contribute significantly to FAB scores. Thus, FAB should be treated as "frontal" rather than "executive" screening task, in line with its name.