Frontal assessment battery and differential diagnosis of frontotemporal dementia and Alzheimer disease

Background: The different distribution of pathologic features in frontotemporal dementia (FTD) and Alzheimer disease (AD) predicts a predominant dysexecutive syndrome in FTD. The Frontal Assessment Battery (FAB) has previously been validated in diseases associated with a frontal lobe dysfunction. Objective: To evaluate the sensitivity of the FAB to differentiate FTD and AD. Design: Comparison study. Setting: Memory Clinic of the Salpetriere Hospital, Paris, France. Patients: Twenty-six patients with FTD and 64 patients with AD. Main Outcome Measures: Comparison of FAB and Mini-Mental State Examination (MMSE) scores between patients with FTD and those with AD. Results: The mean +/- SD FAB scores significantly differed between patients with FTD (7.6 +/- 4.2) and those with AD (12.6 +/- 3.7) (P<.001), but not MMSE scores. The FAB correctly identified 78.9% of the patients. These results were maintained in a subgroup of mildly demented patients (MMSE score, greater than or equal to 24). In these patients, a cutoff score of 12 on the FAB was optimal to differentiate both disorders (sensitivity, 77%; specificity, 87%). Conclusions: The FAB takes less than 10 minutes to administer and provides an objective measure to distinguish FTD from AD in mildly demented patients.